On Monday representatives of the 28 European Union Countries voted to extend the license of the weed-killer glyphosate for the next five years. Glyphosate (N-phosphonomethylglycine), the active ingredient in the herbicide Roundup is manufactured by Monsanto (though the formulation is no longer under patent) and is the most popular herbicide in use today in the United States, and the European Union.
The news release issued by the European Union’s Brussels office stated that 18 countries had backed its proposal to renew the chemical’s license. Nine countries voted against and Portugal abstained, giving a “positive opinion” by the narrowest possible margin under rules requiring both a majority of countries but also the countries representing a majority of the European Union’s 500 million citizens.
The final vote came after two years of wrestling with the issue among the 28 member states in Brussels. Germany had abstained in previous votes, but finally backed a European Commission proposal supported by Spain and the still member United Kingdom against the wishes of France.
Glyphosate was labeled a probable carcinogen by the International Agency for Research on Cancer, IARC, which is the cancer research arm of the World Health Organization, which two yeas ago labeled five insect and weed killers including glyphosate potential carcinogens. It based its finding on “limited evidence” of carcinogenicity in humans and “sufficient evidence” in experimental animals. It said, among other things, that there was a “positive association” between glyphosate and blood cancers.
However, Aaron Blair, the epidemiologist from the U.S. National Cancer Institute who chaired the meeting that found glyphosate a potential carcinogen had seen important unpublished scientific data from research showing no evidence of a link between glyphosate and cancer. According to Reuters new service in a sworn deposition given in March of 2017 Aaron Blair said that the data if reported to the IARC would have altered their analysis and made it less likely that glyphosate would meet the agency’s criteria for being classed as “probably carcinogenic.”
Reuters reviewed court documents from an ongoing U.S. legal case against Monsanto and spoke to both Monsanto representatives, representative from the U.S. National Cancer Institute and Aaron Blair and reported: that Monsanto representatives told Reuters reporters that “the data was deliberately concealed by Blair, but provided no specific evidence of it being hidden.”
Aaron Blair “told Reuters the data, which was available two years before IARC assessed glyphosate, was not published in time because "there was too much to fit into one scientific paper. "
Thursday, November 30, 2017
Monday, November 27, 2017
Most of our Water Footprint is in Food
The water we use is our water footprint. When we think about our use of water, we think of our domestic use of water in our homes for drinking, food preparation, washing clothes and dishes, bathing , and flushing toilets, watering lawns and gardens or maintaining pools, ponds, hosing off patios and decks, washing cars and similar activities. However, most of our water footprint is the “virtual water” used to produce the food we eat, the products we buy and the energy we use.
Mankind uses a lot of water. According to a group of researchers in the Netherlands who have been studying, quantifying and mapping national water footprints since the beginning of this century, mankind uses 9,087 billion cubic meters of water each year. Most of the water use occurs in agricultural production an estimated 92% when utilization of rainwater is counted.
The first global study on the water footprints of nations was carried out by Hoekstra and Hung in 2002 and Hoekstra and Chapagain continued to refine the methods of assessing national water footprints with a series of studies in the following decade culminating in the “The Water Footprint Assessment Manual” by Arjen Y. Hoekstra, Ashok K. Chapagain, Maite M. Aldaya and Mesfin M. Mekonnen.
According to their methodology a water footprint has three components: green, blue and grey. The blue water footprint refers to consumption of fresh water resources (surface and ground water). The green water footprint is the amount of rainwater consumed, which is particularly relevant in crop production. The grey water footprint is an indicator of the degree of freshwater pollution and is defined as the volume of freshwater that is required to assimilate the load of pollutants based on existing ambient water quality standards.
In a study published in 2011 Drs. Hoekstra and Mekonnen determined that China, India and the United States are the countries with the largest total water footprints within their territory, with total water footprints of 1,207, 1,182 and 1,053 billion cubic meters of water per year, respectively. The researchers estimated that these countries account for 38% of water footprint of global production.
India is the country with the largest blue water footprint within its territory: 243 billion cubic meters per year. Irrigation of wheat is the process that takes the largest share (33%) in India’s blue water footprint, followed by irrigation of rice (24%) and irrigation of sugarcane (16%). China is the country with the largest grey water footprint within its borders: 360 billion cubic meters per year, which is 26% of the global grey water footprint.
The water footprint of the average global citizen was 1,385 m3/year. The average consumer in the United States has a water footprint of 2,842 m3/year, while the average citizens in China and India have water footprints of 1,071 m3/year and 1,089 m3/year respectively. Remember that the largest component of the water footprint of mankind is agriculture. According to the 2011 Hoekstra and Mekonnen study, cereal products account for the largest portion of the water footprint of the average global citizen (27%), followed by meat (22%) and milk products (7%).
Mankind uses a lot of water. According to a group of researchers in the Netherlands who have been studying, quantifying and mapping national water footprints since the beginning of this century, mankind uses 9,087 billion cubic meters of water each year. Most of the water use occurs in agricultural production an estimated 92% when utilization of rainwater is counted.
The first global study on the water footprints of nations was carried out by Hoekstra and Hung in 2002 and Hoekstra and Chapagain continued to refine the methods of assessing national water footprints with a series of studies in the following decade culminating in the “The Water Footprint Assessment Manual” by Arjen Y. Hoekstra, Ashok K. Chapagain, Maite M. Aldaya and Mesfin M. Mekonnen.
According to their methodology a water footprint has three components: green, blue and grey. The blue water footprint refers to consumption of fresh water resources (surface and ground water). The green water footprint is the amount of rainwater consumed, which is particularly relevant in crop production. The grey water footprint is an indicator of the degree of freshwater pollution and is defined as the volume of freshwater that is required to assimilate the load of pollutants based on existing ambient water quality standards.
In a study published in 2011 Drs. Hoekstra and Mekonnen determined that China, India and the United States are the countries with the largest total water footprints within their territory, with total water footprints of 1,207, 1,182 and 1,053 billion cubic meters of water per year, respectively. The researchers estimated that these countries account for 38% of water footprint of global production.
India is the country with the largest blue water footprint within its territory: 243 billion cubic meters per year. Irrigation of wheat is the process that takes the largest share (33%) in India’s blue water footprint, followed by irrigation of rice (24%) and irrigation of sugarcane (16%). China is the country with the largest grey water footprint within its borders: 360 billion cubic meters per year, which is 26% of the global grey water footprint.
The water footprint of the average global citizen was 1,385 m3/year. The average consumer in the United States has a water footprint of 2,842 m3/year, while the average citizens in China and India have water footprints of 1,071 m3/year and 1,089 m3/year respectively. Remember that the largest component of the water footprint of mankind is agriculture. According to the 2011 Hoekstra and Mekonnen study, cereal products account for the largest portion of the water footprint of the average global citizen (27%), followed by meat (22%) and milk products (7%).
Monday, November 20, 2017
What's in the Wells of Fairfax County 2017
What is tested for are mostly the naturally occurring contaminants and common sources of contamination: a poorly sealed well or a nearby leaking septic system, or indications of plumbing system corrosion. Though this is not an exhaustive list of potential contaminants, these are the most common contaminants that effect drinking water wells. The chart below shows what was found in the 75 samples tested in Fairfax County in 2017.
In order to determine if treatment is necessary, water test results should be compared to a standard. The standard we use is the U.S.EPA Safe Drinking Water Act (SDW) limits. Though private wells do not fall under the regulatory authority of the U.S. Environmental Protection Agency (EPA) or the Safe Drinking Water Act, the SDW act has primary and secondary drinking water standards that we use for comparison. Primary standards are ones that can impact health and from the tested substances include: coliform bacteria, E. coli bacteria, nitrate, lead, and arsenic. Secondary standards impact taste or the perceived quality of the water.
The 2017 Fairfax County water clinic found that over 37% of the wells tested present for coliform bacteria. Coliform bacteria are not a health threat itself, it is used to indicate other bacteria that may be present and identify that a well is not properly sealed from surface bacteria. The federal standard for coliform bacteria is zero, but the federal standard allows that up to 5% of samples can test positive for coliform during a month.
Two of the homes tested positive for E coli. Fecal coliform and E. coli are bacteria whose presence indicates that the water is contaminated with human or animal wastes. Disease-causing microbes (pathogens) in these wastes can cause diarrhea, cramps, nausea, headaches, or other symptoms. These pathogens may pose a special health risk for infants, young children, and those with compromised immune systems. However, people can drink water contaminated with fecal bacteria and not notice.
If your water is contaminated with coliform but not fecal coliform or E. coli, then you have a nuisance bacteria problem and the source may be infiltration from the surface from rain or snow melt. Typical causes are improperly sealed well cap, failed grouting or surface drainage to the well. Shock chlorinate the well, repack the soil around the well pipe to flow away from the well and replace the well cap. Then after the next big rainstorm retest the well for coliform. If it is still present then a long-term treatment should be implemented: using UV light, ozonation, or chlorine for continuous disinfection. These systems can cost up to $2,000 installed.
If you have fecal coliform in the well or E. coli, your well is being impacted by human or animal waste and you are drinking dilute sewage. If there is not a nearby animal waste composting facility, then you are probably drinking water from a failed septic system- yours or your nearest neighbors. To solve this problem you need to fix or replace the septic system that is causing the contamination, replace the well or install a disinfection and filtration system. Disinfection does not kill Giardia or Cryptosporidium, two microscopic parasites that can be found in groundwater that has been impacted by surface water or sewage. Both parasites produce cysts that cause illness and sometimes death.
Membrane filtration is the usual treatment for these parasites- a one micron membrane is required after disinfection and can be accomplished at home with a reverse osmosis system. The failing septic systems can often be identified by using tracer dyes. While continuous disinfection will work to protect you from fecal bacteria and E. coli, be aware that if your well is being impacted by a septic system, then the well water might also have present traces of all the chemicals and substances that get poured down the drain. Long term treatment for disinfection, and micro-filtration should be implemented: using UV light, ozonation, or chlorine for continuous disinfection, carbon filtration, and anything that is used for drinking should be further treated with a reverse osmosis systems or micro membrane system that works by using pressure to force water through a semi-permeable membrane. Large quantities of wastewater are produced by reverse osmosis systems and need to bypass the septic system or they will overwhelm that system creating more groundwater problems. Reverse osmosis systems produce water very slowly, a pressurized storage tank and special faucet needs to be installed so that water is available to meet the demand for drinking and cooking.
Nitrate can contaminate well water from fertilizer use; leaking from septic tanks, sewage and erosion of natural deposits. None of the wells in our group of 101 samples had nitrate levels above the MCL. The MCL for nitrate is 10 mg/L. Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill from blue-baby syndrome and, if untreated, may die. Symptoms include shortness of breath and a blue ting to the skin common in blue-baby syndrome. The NO3 dissolves and moves easily through soil which varies seasonally and over time as plants use up the nitrate over the summer. Testing in the spring will usually produce the highest levels. Nitrate may indicate contamination from septic tanks, but do not boil the water- boiling water reduces the water and actually INCREASES the concentration of nitrates. Reverse osmosis, or ion exchange is necessary to control the nitrate. None of the wells tested exceeded the MCL.
IThis year we had 9.3% of homes have first draw lead levels above the SDWA maximum contaminant level of 0.015 Mg/L. After the flushing the tap for at least one minute only one home had lead levels above the 0.15 mg/L level; however, many scientists do not believe that any level of lead is safe to drink over an extended period of time. In the homes that had elevated lead in the first draw, it tends to be negatively correlated with pH values and copper pipes. Houses built before 1988 when the ban on lead went into effect and have low pH water typically have higher lead concentrations. Lead leaches into water primarily as a result of corrosion of plumbing and well components, but can also result from flaking of scale from brass fittings and well components unrelated to corrosion and corrosion control techniques such as adjusting pH or alkalinity that are commonly used to neutralize aggressive water will not work in those cases. For most instances, though, a neutralizing filter and lead removing activated carbon filters can be used to remove lead. Recently, some home water treatment companies are offering in home treatment systems that neutralize the water and add orthophosphate other phosphate solution to coat the piping to prevent further corrosion. It should work, but I have never seen such a home system and am not aware of any testing.
Iron and manganese are naturally occurring elements commonly found in groundwater in this part of the country. 8.0% of the wells tested exceed the iron standard and 6.7% exceeded the manganese standard. At naturally occurring levels iron and manganese do not present a health hazard. However, their presence in well water can cause unpleasant taste, staining and accumulation of mineral solids that can clog water treatment equipment and plumbing and discolored water. The standard Secondary Maximum Contaminant Level (SMCL) for iron is 0.3 milligrams per liter (mg/L or ppm) and 0.05 mg/L for manganese. This level of iron and manganese can be detected by taste, smell or appearance. In addition, some types of bacteria react with soluble forms of iron and manganese and form persistent bacterial contamination in a well, water system and any treatment systems. These organisms change the iron and manganese from a soluble form into a less soluble form, thus causing precipitation and accumulation of black or reddish brown gelatinous material (slime). Masses of mucous, iron, and/or manganese can clog plumbing and water treatment equipment.
All systems of removing iron and manganese essentially involve oxidation of the soluble form or killing and removal of the iron bacteria. When the total combined iron and manganese concentration is less than 15 mg/l, an oxidizing filter is the recommended solution. An oxidizing filter supplies oxygen to convert ferrous iron into a solid form which can be filtered out of the water. Higher concentrations of iron and manganese can be treated with an aeration and filtration system. This system is not effective on water with iron/ manganese bacteria, but is very effective on soluble iron and manganese so you need to do further testing to determine what type of iron/manganese you have before you install a treatment system. Water softeners can remove low levels of iron and are widely sold for this purpose because they are very profitable, but are not recommended for just this purpose. Chemical oxidation can be used to remove high levels of dissolved or oxidized iron and manganese as well as treat the presence of iron/manganese (or even sulfur) bacteria. The system consists of a small pump that puts an oxidizing agent into the water before the pressure tank. The water will need about 20 minutes for oxidation to take place so treating before a holding tank or pressure tank is a must. After the solid particles have formed the water is filtered. The best oxidizing agents are chlorine or hydrogen peroxide. If chlorine is used, an activated carbon filter is often used to finish the water and remove the chlorine taste. The holding tank or pressure tank will have to be cleaned regularly to remove any settled particles.
The pH of water is a measure of the acidity or alkalinity. The pH is a logarithmic scale from 0 – 14 with 1 being very acidic and 14 very alkaline. Drinking water should be between 6.5 and 7.5. For reference and to put this into perspective, coffee has a pH of around 5 and salt water has a pH of around 9. Corrosive water, sometimes also called aggressive water is typically water with a low pH. (Alkaline water can also be corrosive.) Low pH water can corrode metal plumbing fixtures causing lead and copper to leach into the water and causing pitting and leaks in the plumbing system. The presence of lead or copper in water is most commonly leaching from the plumbing system rather than the groundwater. Acidic water is easily treated using an acid neutralizing filter. Typically these neutralizing filters use a granular marble, calcium carbonate or lime. If the water is very acidic a mixing tank using soda ash, sodium carbonate or sodium hydroxide can be used. The acid neutralizing filters will increase the hardness of the water because of the addition of calcium carbonate. The sodium based systems will increase the salt content in the water. Eight percent of the wells tested were found to have acidic water this year.
Water that contains high levels of dissolved minerals is commonly referred to as hard. Groundwater very slowly wears away at the rocks and minerals picking up small amounts of calcium and magnesium ions. Water containing approximately 125 mg/L can begin to have a noticeable impact and is considered hard. Concentrations above 180 mg/L are considered very hard. As the mineral level climbs, bath soap combines with the minerals and forms a pasty scum that accumulates on bathtubs and sinks. You either must use more soap and detergent in washing or use specially formulated hard water soap solutions. Hard water can be just a minor annoyance with spotting and the buildup of lime scale, but once water reaches the very hard level 180 mg/L or 10.5 grains per gallon, it can become problematic. One a well tested at 254.2 mg/L, but overall only 9.3% of homes tested had hard water. Given the number of homes with elevated sodium and our local geology, it is probably a reflection of the number of homes with water softeners.
Water softening systems are used to address the problem are basically an ion exchange system. The water softening system consists of a mineral tank and a brine tank. The water supply pipe is connected to the mineral tank so that water coming into the house must pass through the tank before it can be used. The mineral tank holds small beads of resin that have a negative electrical charge. The calcium and magnesium ions are positively charged and are attracted to the negatively charged beads. This attraction makes the minerals stick to the beads as the hard water passes through the mineral tank. Sodium is often used to charge the resin beads. Water softeners can be used to remove small amounts of other metals like iron and some forms of arsenic. As the water is softened, the sodium ions are replaced and small quantities of sodium are released into the softened water, thus the salty taste of softened water. When the water softening system is recharged the excess sodium solution carrying the calcium and magnesium is flushed to the septic system which may shorten the life of the drain field.
At the present time the EPA guidance level for sodium in drinking water is 20 mg/L. This level was developed for those restricted to a total sodium intake of 500 mg/day and does not necessarily represent a necessary level for the rest of the population. Based on taste of the water levels of sodium should be below 30 to 60 mg/L based on individual taste. Water softeners ten to cost around $4,500 installed. They are often sold to solve every water quality problem because they have some ability to remove other contaminants. The resin bed used will determine specific contaminant removal. Softened water can have a low pH and high levels of chloride, corrosion control problems and softening systems can encourage the growth of reducing bacteria. Water softening systems add sodium. Reverse osmosis systems and distillation systems remove sodium and are safe for household use, but addressing hard water by using vinegar to descale pots and dishwashers, regularly draining hot water heaters, and using detergents formulated for hard water might be a better solution for you if your water like mine is only modestly hard.
No wells were found that had arsenic exceeding the EPA MCL for drinking water of 10 ppm. While arsenic is a naturally occurring element found in soil and groundwater it is not typically found at significantly elevated levels in this geology. Arsenic can also be an indication of industrial or pesticide contamination. Arsenic can be very tricky to remove depending on its form and the other contaminants present. Possible solutions for elevated levels of naturally occurring arsenic are reverse osmosis system or iron oxide filter system.
In order to determine if treatment is necessary, water test results should be compared to a standard. The standard we use is the U.S.EPA Safe Drinking Water Act (SDW) limits. Though private wells do not fall under the regulatory authority of the U.S. Environmental Protection Agency (EPA) or the Safe Drinking Water Act, the SDW act has primary and secondary drinking water standards that we use for comparison. Primary standards are ones that can impact health and from the tested substances include: coliform bacteria, E. coli bacteria, nitrate, lead, and arsenic. Secondary standards impact taste or the perceived quality of the water.
The 2017 Fairfax County water clinic found that over 37% of the wells tested present for coliform bacteria. Coliform bacteria are not a health threat itself, it is used to indicate other bacteria that may be present and identify that a well is not properly sealed from surface bacteria. The federal standard for coliform bacteria is zero, but the federal standard allows that up to 5% of samples can test positive for coliform during a month.
Two of the homes tested positive for E coli. Fecal coliform and E. coli are bacteria whose presence indicates that the water is contaminated with human or animal wastes. Disease-causing microbes (pathogens) in these wastes can cause diarrhea, cramps, nausea, headaches, or other symptoms. These pathogens may pose a special health risk for infants, young children, and those with compromised immune systems. However, people can drink water contaminated with fecal bacteria and not notice.
If your water is contaminated with coliform but not fecal coliform or E. coli, then you have a nuisance bacteria problem and the source may be infiltration from the surface from rain or snow melt. Typical causes are improperly sealed well cap, failed grouting or surface drainage to the well. Shock chlorinate the well, repack the soil around the well pipe to flow away from the well and replace the well cap. Then after the next big rainstorm retest the well for coliform. If it is still present then a long-term treatment should be implemented: using UV light, ozonation, or chlorine for continuous disinfection. These systems can cost up to $2,000 installed.
If you have fecal coliform in the well or E. coli, your well is being impacted by human or animal waste and you are drinking dilute sewage. If there is not a nearby animal waste composting facility, then you are probably drinking water from a failed septic system- yours or your nearest neighbors. To solve this problem you need to fix or replace the septic system that is causing the contamination, replace the well or install a disinfection and filtration system. Disinfection does not kill Giardia or Cryptosporidium, two microscopic parasites that can be found in groundwater that has been impacted by surface water or sewage. Both parasites produce cysts that cause illness and sometimes death.
Membrane filtration is the usual treatment for these parasites- a one micron membrane is required after disinfection and can be accomplished at home with a reverse osmosis system. The failing septic systems can often be identified by using tracer dyes. While continuous disinfection will work to protect you from fecal bacteria and E. coli, be aware that if your well is being impacted by a septic system, then the well water might also have present traces of all the chemicals and substances that get poured down the drain. Long term treatment for disinfection, and micro-filtration should be implemented: using UV light, ozonation, or chlorine for continuous disinfection, carbon filtration, and anything that is used for drinking should be further treated with a reverse osmosis systems or micro membrane system that works by using pressure to force water through a semi-permeable membrane. Large quantities of wastewater are produced by reverse osmosis systems and need to bypass the septic system or they will overwhelm that system creating more groundwater problems. Reverse osmosis systems produce water very slowly, a pressurized storage tank and special faucet needs to be installed so that water is available to meet the demand for drinking and cooking.
Nitrate can contaminate well water from fertilizer use; leaking from septic tanks, sewage and erosion of natural deposits. None of the wells in our group of 101 samples had nitrate levels above the MCL. The MCL for nitrate is 10 mg/L. Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill from blue-baby syndrome and, if untreated, may die. Symptoms include shortness of breath and a blue ting to the skin common in blue-baby syndrome. The NO3 dissolves and moves easily through soil which varies seasonally and over time as plants use up the nitrate over the summer. Testing in the spring will usually produce the highest levels. Nitrate may indicate contamination from septic tanks, but do not boil the water- boiling water reduces the water and actually INCREASES the concentration of nitrates. Reverse osmosis, or ion exchange is necessary to control the nitrate. None of the wells tested exceeded the MCL.
IThis year we had 9.3% of homes have first draw lead levels above the SDWA maximum contaminant level of 0.015 Mg/L. After the flushing the tap for at least one minute only one home had lead levels above the 0.15 mg/L level; however, many scientists do not believe that any level of lead is safe to drink over an extended period of time. In the homes that had elevated lead in the first draw, it tends to be negatively correlated with pH values and copper pipes. Houses built before 1988 when the ban on lead went into effect and have low pH water typically have higher lead concentrations. Lead leaches into water primarily as a result of corrosion of plumbing and well components, but can also result from flaking of scale from brass fittings and well components unrelated to corrosion and corrosion control techniques such as adjusting pH or alkalinity that are commonly used to neutralize aggressive water will not work in those cases. For most instances, though, a neutralizing filter and lead removing activated carbon filters can be used to remove lead. Recently, some home water treatment companies are offering in home treatment systems that neutralize the water and add orthophosphate other phosphate solution to coat the piping to prevent further corrosion. It should work, but I have never seen such a home system and am not aware of any testing.
Iron and manganese are naturally occurring elements commonly found in groundwater in this part of the country. 8.0% of the wells tested exceed the iron standard and 6.7% exceeded the manganese standard. At naturally occurring levels iron and manganese do not present a health hazard. However, their presence in well water can cause unpleasant taste, staining and accumulation of mineral solids that can clog water treatment equipment and plumbing and discolored water. The standard Secondary Maximum Contaminant Level (SMCL) for iron is 0.3 milligrams per liter (mg/L or ppm) and 0.05 mg/L for manganese. This level of iron and manganese can be detected by taste, smell or appearance. In addition, some types of bacteria react with soluble forms of iron and manganese and form persistent bacterial contamination in a well, water system and any treatment systems. These organisms change the iron and manganese from a soluble form into a less soluble form, thus causing precipitation and accumulation of black or reddish brown gelatinous material (slime). Masses of mucous, iron, and/or manganese can clog plumbing and water treatment equipment.
All systems of removing iron and manganese essentially involve oxidation of the soluble form or killing and removal of the iron bacteria. When the total combined iron and manganese concentration is less than 15 mg/l, an oxidizing filter is the recommended solution. An oxidizing filter supplies oxygen to convert ferrous iron into a solid form which can be filtered out of the water. Higher concentrations of iron and manganese can be treated with an aeration and filtration system. This system is not effective on water with iron/ manganese bacteria, but is very effective on soluble iron and manganese so you need to do further testing to determine what type of iron/manganese you have before you install a treatment system. Water softeners can remove low levels of iron and are widely sold for this purpose because they are very profitable, but are not recommended for just this purpose. Chemical oxidation can be used to remove high levels of dissolved or oxidized iron and manganese as well as treat the presence of iron/manganese (or even sulfur) bacteria. The system consists of a small pump that puts an oxidizing agent into the water before the pressure tank. The water will need about 20 minutes for oxidation to take place so treating before a holding tank or pressure tank is a must. After the solid particles have formed the water is filtered. The best oxidizing agents are chlorine or hydrogen peroxide. If chlorine is used, an activated carbon filter is often used to finish the water and remove the chlorine taste. The holding tank or pressure tank will have to be cleaned regularly to remove any settled particles.
The pH of water is a measure of the acidity or alkalinity. The pH is a logarithmic scale from 0 – 14 with 1 being very acidic and 14 very alkaline. Drinking water should be between 6.5 and 7.5. For reference and to put this into perspective, coffee has a pH of around 5 and salt water has a pH of around 9. Corrosive water, sometimes also called aggressive water is typically water with a low pH. (Alkaline water can also be corrosive.) Low pH water can corrode metal plumbing fixtures causing lead and copper to leach into the water and causing pitting and leaks in the plumbing system. The presence of lead or copper in water is most commonly leaching from the plumbing system rather than the groundwater. Acidic water is easily treated using an acid neutralizing filter. Typically these neutralizing filters use a granular marble, calcium carbonate or lime. If the water is very acidic a mixing tank using soda ash, sodium carbonate or sodium hydroxide can be used. The acid neutralizing filters will increase the hardness of the water because of the addition of calcium carbonate. The sodium based systems will increase the salt content in the water. Eight percent of the wells tested were found to have acidic water this year.
Water that contains high levels of dissolved minerals is commonly referred to as hard. Groundwater very slowly wears away at the rocks and minerals picking up small amounts of calcium and magnesium ions. Water containing approximately 125 mg/L can begin to have a noticeable impact and is considered hard. Concentrations above 180 mg/L are considered very hard. As the mineral level climbs, bath soap combines with the minerals and forms a pasty scum that accumulates on bathtubs and sinks. You either must use more soap and detergent in washing or use specially formulated hard water soap solutions. Hard water can be just a minor annoyance with spotting and the buildup of lime scale, but once water reaches the very hard level 180 mg/L or 10.5 grains per gallon, it can become problematic. One a well tested at 254.2 mg/L, but overall only 9.3% of homes tested had hard water. Given the number of homes with elevated sodium and our local geology, it is probably a reflection of the number of homes with water softeners.
Water softening systems are used to address the problem are basically an ion exchange system. The water softening system consists of a mineral tank and a brine tank. The water supply pipe is connected to the mineral tank so that water coming into the house must pass through the tank before it can be used. The mineral tank holds small beads of resin that have a negative electrical charge. The calcium and magnesium ions are positively charged and are attracted to the negatively charged beads. This attraction makes the minerals stick to the beads as the hard water passes through the mineral tank. Sodium is often used to charge the resin beads. Water softeners can be used to remove small amounts of other metals like iron and some forms of arsenic. As the water is softened, the sodium ions are replaced and small quantities of sodium are released into the softened water, thus the salty taste of softened water. When the water softening system is recharged the excess sodium solution carrying the calcium and magnesium is flushed to the septic system which may shorten the life of the drain field.
At the present time the EPA guidance level for sodium in drinking water is 20 mg/L. This level was developed for those restricted to a total sodium intake of 500 mg/day and does not necessarily represent a necessary level for the rest of the population. Based on taste of the water levels of sodium should be below 30 to 60 mg/L based on individual taste. Water softeners ten to cost around $4,500 installed. They are often sold to solve every water quality problem because they have some ability to remove other contaminants. The resin bed used will determine specific contaminant removal. Softened water can have a low pH and high levels of chloride, corrosion control problems and softening systems can encourage the growth of reducing bacteria. Water softening systems add sodium. Reverse osmosis systems and distillation systems remove sodium and are safe for household use, but addressing hard water by using vinegar to descale pots and dishwashers, regularly draining hot water heaters, and using detergents formulated for hard water might be a better solution for you if your water like mine is only modestly hard.
No wells were found that had arsenic exceeding the EPA MCL for drinking water of 10 ppm. While arsenic is a naturally occurring element found in soil and groundwater it is not typically found at significantly elevated levels in this geology. Arsenic can also be an indication of industrial or pesticide contamination. Arsenic can be very tricky to remove depending on its form and the other contaminants present. Possible solutions for elevated levels of naturally occurring arsenic are reverse osmosis system or iron oxide filter system.
Thursday, November 16, 2017
New Study finds no Cancer Link to Glyphosate
A new study published last week in the Journal of the National Cancer Institute found no association between cancer and exposure to glyphosate, the active ingredient in the herbicide “Roupndup” and the most commonly used herbicide worldwide. In 2015, the International Agency for Research on Cancer classified glyphosate as “probably carcinogenic to humans,” noting strong mechanistic evidence and positive associations for non-Hodgkin lymphoma (NHL) in some epidemiologic studies; though previous evaluations had found no statistically significant associations with glyphosate use and any cancer,
This new study is part of the Agricultural Health Study which has been tracking the health of thousands of agricultural workers and pesticide applicators and their families in Iowa and North Carolina for over 20 years. The study was led by Laura Beane Freeman of the National Cancer Institute. The Agricultural Health Study has tracked and studied 54,251 pesticide applicators, 44,932 or 82.9% who had used glyphosate since the 1990’s.
The scientists studied of glyphosate use and cancer occurrence in this large group of pesticide applicators, and observed no associations between glyphosate use and overall cancer risk or with total lymphohematopoietic cancers, including NHL and multiple myeloma. However, the scientist found some evidence of an increased risk of acute myeloid leukemia (AML) for applicators, particularly in the highest category of glyphosate exposure compared with those who never used glyphosate. The fact that no other studies have reported an association between glyphosate and AML risk calls for cautious interpretation of the results. However, the observed pattern of increasing risk with increasing exposure and the lagged exposure of 10 or more years raises concern and the need for additional long term studies.
Today, Americans spray an estimated 180-185 million pounds of the weed killer, on their yards and farms every year. All the acute toxicity tests have indicated glyphosate is nearly nontoxic to mammals, but concern has been raised about long term exposure. The current findings are reassuring, but given the prevalence of use of this herbicide not only in the United States but worldwide, efforts should be undertaken to replicate these findings as soon as possible.
This new study is part of the Agricultural Health Study which has been tracking the health of thousands of agricultural workers and pesticide applicators and their families in Iowa and North Carolina for over 20 years. The study was led by Laura Beane Freeman of the National Cancer Institute. The Agricultural Health Study has tracked and studied 54,251 pesticide applicators, 44,932 or 82.9% who had used glyphosate since the 1990’s.
The scientists studied of glyphosate use and cancer occurrence in this large group of pesticide applicators, and observed no associations between glyphosate use and overall cancer risk or with total lymphohematopoietic cancers, including NHL and multiple myeloma. However, the scientist found some evidence of an increased risk of acute myeloid leukemia (AML) for applicators, particularly in the highest category of glyphosate exposure compared with those who never used glyphosate. The fact that no other studies have reported an association between glyphosate and AML risk calls for cautious interpretation of the results. However, the observed pattern of increasing risk with increasing exposure and the lagged exposure of 10 or more years raises concern and the need for additional long term studies.
Today, Americans spray an estimated 180-185 million pounds of the weed killer, on their yards and farms every year. All the acute toxicity tests have indicated glyphosate is nearly nontoxic to mammals, but concern has been raised about long term exposure. The current findings are reassuring, but given the prevalence of use of this herbicide not only in the United States but worldwide, efforts should be undertaken to replicate these findings as soon as possible.
Monday, November 13, 2017
Arsenic in Your Well Water
A new study from the U.S. Geological Survey and Centers for Disease Control and Prevention was released last month. The author estimates that about 2.1 million people in the U.S. may be getting their drinking water from private domestic wells considered to have high concentrations of naturally occurring arsenic, presumed to be coming primarily from rocks and minerals through which the water flows.
About 44 million people in the lower 48 states use water from domestic wells,” said Joe Ayotte, a USGS hydrologist and lead author of the study. Private wells are the dominant source of drinking water for people living in rural parts of the United States. In most of the U.S., domestic well water quality is not regulated; it is up to the well owner to understand the arsenic hazard and other water quality hazards and take steps to test their water and treat it if necessary. This study is a good reminder that prudent, routine testing of the water is an essential first step for these homeowners and their families.
Using water samples from more than 20,000 domestic wells, the researchers developed a statistical model that estimates the probability of having high arsenic in domestic wells in a specific area. The researcher used a standard of 10 micrograms of arsenic per liter -- the maximum contaminant level allowed for public water supplies and used it developed maps of the contiguous U.S. showing locations where there are likely higher levels of arsenic in groundwater, and how many people may be using it. They used that model in combination with information on the U.S. domestic well population to estimate the population in each county of the continental United States with potentially high concentrations of arsenic in domestic wells.
Much of the country is potentially impacted by arsenic and is a national public health concern. Some of the locations where the authors estimated the most people have high-levels of arsenic in private domestic well water include:
- Much of the West – Washington, Oregon, Nevada, California, Arizona, New Mexico
- Parts of the Northeast and Midwest – Maine, Massachusetts, New Hampshire, New Jersey, Maryland, Michigan, Wisconsin, Illinois Ohio, Indiana
- Some of the Atlantic southeast coastal states – Florida, Virginia, North Carolina, South Carolina
Like may other contaminants, high concentrations of arsenic in water do not effect taste or smell, the only way to know how much arsenic is in drinking water is to have it tested. Testing you well is the first step in ensuring the safety of your drinking water supply. After testing it may be necessary to treat the water to reduce or eliminating the health risks or concerns.
You may wish to consider water treatment methods such as reverse osmosis, ultra-filtration, distillation, or as a last choice ion exchange. Typically these methods are used to treat water at only one faucet. Though anionic exchange systems (water softeners) are whole house systems, they may not be the best choice. These systems use a physical/chemical process to exchange ions between a resin bed and water passing through. These systems can remove calcium carbonate, iron and manganese, and lower nitrate and arsenic levels. Specific contaminant removal is determined by the composition of the resin bed used. Other constituents in water can compete with arsenic for the resin sites reducing the systems effectiveness. Also, depending on your water chemistry, they may create other problems.
To understand the risk and to make progress on reducing exposure in a systematic way, we need better understanding of groundwater chemistry and estimates of the population affected by high arsenic concentrations and other contaminants. The work by the USGS and the Virginia Household Quality Program accumulates data and helps homeowners identify these risks.
Thursday, November 9, 2017
Neonicotinoids in Honey
In a recent study published in Science, Mitchell et al found that most honey sampled from around the world between 2012 and 2016 contained neonicotinoid pesticides at levels known to be neuroactive to bees. Neonicotinoid are currently the most widely used class of pesticides worldwide. The neonicotinoids are taken up by plants and contaminate the pollen and nectar. Neonicotinoids have been identified or suspected as a key factor responsible for the decline in bees.
During the winter of 2006-2007, a large number of bee colonies died out, losses at the impacted beekeeping operations were reported to be from 30% to 90%. While many of the colonies lost during this time period exhibited the symptoms from parasitic mites, many were lost, from unknown cause. The next winter, the number of impacted honey bee operations spread across the country. The phenomenon was termed Colony Collapse Disorder.
Over the past decade Colony Collapse Disorder has spread around the world. In 2012, 31% of the U.S. honey bee colonies were wiped out. The year before that it was reported as 21% of colonies lost. These losses if they continue could have a catastrophic impact on agriculture. One third of all food eaten in the United States requires honey bee pollination.
Recent field studies published this year in Science have found widespread contamination of agricultural land worldwide by neonicotinoid pesticides. These findings suggest that chronic low level exposure to neonicotinoids may be impacting bee colonies. Currently pesticide safety testing focuses on acute exposure risk not extremely low levels of chronic exposure. Neonicotinoids work by targeting the nicotinic acetylcholine receptors in the insect brain which are responsible for learning and memory. Acute activation of theses receptors by neonicotinoids causes seizure then neuron non-response.
During experiments carried out by Piroinen et al in 2016 it was found that low level neonicotinoid exposure causes neural dysfunction that limits a bee’s capacity to learn and remember. Chronic exposure resulted in reduced foraging ability (Gill et al 2012) and poor colony growth (Moffat et al 2015, 2016) and is believed to be a factor in Colony Collapse Disorder.
The vast majority of plants are pollinated by insects, and bees are responsible for the vast majority of pollination. Commercial agriculture uses honey bees raised to pollinate its crops. A Cornell University study estimates that the value of honey bee pollination in the United States is more than $14.6 billion annually.
In the current study, Dr. Mitchell found neonicotinoids in 75% of 198 honey samples collected from honey producers. In North America 86% of the samples had neonicotinoids detected. The concentrations found in honey are below the maximum residue level allowed for human consumption, but within the bioactive range for honey bees.
Although recording of pesticide use is required in the European Union and the United States (under the 1990 Farm Bill), it is not collected into a searchable database that would allow the finding of statistical correlation of pesticides used with human chronic diseases or ecosystem damage. Chronic low level exposure may be more damaging than we ever imagined. It is time to reexamine our assumptions and develop methods to measure impact from chronic low level exposure.
During the winter of 2006-2007, a large number of bee colonies died out, losses at the impacted beekeeping operations were reported to be from 30% to 90%. While many of the colonies lost during this time period exhibited the symptoms from parasitic mites, many were lost, from unknown cause. The next winter, the number of impacted honey bee operations spread across the country. The phenomenon was termed Colony Collapse Disorder.
Over the past decade Colony Collapse Disorder has spread around the world. In 2012, 31% of the U.S. honey bee colonies were wiped out. The year before that it was reported as 21% of colonies lost. These losses if they continue could have a catastrophic impact on agriculture. One third of all food eaten in the United States requires honey bee pollination.
Recent field studies published this year in Science have found widespread contamination of agricultural land worldwide by neonicotinoid pesticides. These findings suggest that chronic low level exposure to neonicotinoids may be impacting bee colonies. Currently pesticide safety testing focuses on acute exposure risk not extremely low levels of chronic exposure. Neonicotinoids work by targeting the nicotinic acetylcholine receptors in the insect brain which are responsible for learning and memory. Acute activation of theses receptors by neonicotinoids causes seizure then neuron non-response.
During experiments carried out by Piroinen et al in 2016 it was found that low level neonicotinoid exposure causes neural dysfunction that limits a bee’s capacity to learn and remember. Chronic exposure resulted in reduced foraging ability (Gill et al 2012) and poor colony growth (Moffat et al 2015, 2016) and is believed to be a factor in Colony Collapse Disorder.
The vast majority of plants are pollinated by insects, and bees are responsible for the vast majority of pollination. Commercial agriculture uses honey bees raised to pollinate its crops. A Cornell University study estimates that the value of honey bee pollination in the United States is more than $14.6 billion annually.
In the current study, Dr. Mitchell found neonicotinoids in 75% of 198 honey samples collected from honey producers. In North America 86% of the samples had neonicotinoids detected. The concentrations found in honey are below the maximum residue level allowed for human consumption, but within the bioactive range for honey bees.
Although recording of pesticide use is required in the European Union and the United States (under the 1990 Farm Bill), it is not collected into a searchable database that would allow the finding of statistical correlation of pesticides used with human chronic diseases or ecosystem damage. Chronic low level exposure may be more damaging than we ever imagined. It is time to reexamine our assumptions and develop methods to measure impact from chronic low level exposure.
Monday, November 6, 2017
Environment Impacts from the Kline Farm Development
Stanley Martin Homes wants to develop farm land owned by the Kline family at the intersection of Prince William Parkway and Libera Avenue. The Prince William County Planning Commission will hold a public hearing on a series of permit requests and zoning changes associated with this development on November 15th 2017 at 7 pm in the Board Chambers of the McCoart Administration Building, 1 County Complex Court, Prince William, VA 22192. If you have an opinion on whether the comprehensive plan and zoning should be amended as described below you should attend and make your voice heard or call you supervisor’s office.
Stanley Martin Homes wants a Comprehensive Plan Amendment (CPA) to change the long-range land use designation for the over 100. acres from CEC, Community Employment Center, and SRR, Semi-Rural Residential, to CEC with a Center of Community Overlay and with an expanded study area. These changes would allow Stanley Martin build 329 townhomes, 63 single-family homes and 400,000 square feet of commercial space and an elementary school. The properties in the development will be connected to public water from supplied by Prince William Public Service Authority and with surface water as the source supply. So, there will be no increase in the use of groundwater in the immediate area.
The Kline Farm property encompasses a bit more than 100 acres and is generally located south and southeast of the intersection of Prince William Parkway and Liberia Avenue, and north of Buckhall Road. The property is located in a transitional area of the county that is adjacent to the City of Manassas. North of the site and across the Prince William Parkway is the Prince William Commerce Center, still under development and will contain mixed retail/commercial/office uses, as well as the suburban residential neighborhood of Arrowood and the semi-rural residential neighborhood of Hyson Knolls to the northeast. East and southeast of the site is semi-rural residential communities and A-1 zoned property. To the west and northwest is the City of Manassas with existing retail service/commercial strip development. Southwest of the subject site is existing suburban residential development.
There are important environment concerns that need to be considered. Residents within the abutting Hynson Knolls community, homeowners bordering Buckhall Road and homes along Lake Jackson Drive rely on private wells for water and septic systems for wastewater disposal. In a “Preliminary Hydrogeological Assessment-Klein Site” prepared by SES/TrueNorth they do a preliminary look at whether the development of the site is likely to have an adverse impact on surrounding private wells and septic systems. The properties in the development will be connected to public water from supplied by Prince William Public Service Authority and with surface water as the source supply. So, there will be no increase in the use of groundwater in the immediate area.
The consultants only reviewed the existing well construction records dating back about 40 years when Hynson Knolls was first developed; existing published hydrology and geology work by the U.S. Geological Survey dating to 1990 and earlier; development of a theoretical groundwater budget and a fracture trace analysis of a 1978 photograph to determining the general flow of groundwater. No physical testing of the aquifer was performed and no recent data records were used.
Private wells draw their water from groundwater. Geology, climate, weather, land use and many other factors determine the quality and quantity of the groundwater available. Within Prince William County Virginia there are four distinct geologic provinces: (1) the Blue Ridge, (2) the Culpeper Basin, (3) the Piedmont, and (4) the Coastal Plain. The U.S. Geological Survey divides the four geologic provinces of the county into seven hydrogeologic groups based on the presence and movement of the ground water calling them groups: A, B, B1, C, D, E and F. About 27 years ago the U.S. Geological Survey studied the groundwater systems within Prince William County. You can review that report if you wish to see the entirety it is by Nelms and Brokman.
The consultants for Stanley Martin Homes identify the site as located within Hydrogeological Group E. The Klein Farm and vicinity are within a fractured bedrock aquifer in which groundwater availability and flow are controlled by fractures and joints within the rock. Hydrogeologic group E consists of metasedimentary, meta-volcanic, and other metamorphic rocks. Rocks within hydrogeologic group E tend to have poor to moderate water-bearing potential, and thin- to thick cover of overburden. Ground-water storage tends to be predominantly in the overburden which is typically relatively granular and porous. This is a water table aquifer separate from but hydraulically connected to the underlying bedrock aquifer. According to that USGS report by Nelms and Brockman, some of the poorest yielding wells are located in hydrogeologic group E.
The fracture trace analysis performed by Stanley Martin Homes consultant found a predominant west-northwest to east-southeast regional fracture orientation; however, there was a notable but less prominent southwest to northeast regional fracture orientation also present. The groundwater flow in Prince William county is generally to the east-southeast, but there is considerable variation and surprises in the flow as documented by monitoring at several cleanup sites in the county and suggested by the fracture analysis.
In developing the theoretical groundwater budget the Stanley Martin Homes consultant assumed that the groundwater recharge rate for the site was equivalent to the average groundwater recharge for Prince William County. This is unlikely to be true. Not only does the geology vary across the county with different water bearing and storage potential in the different hydrogeologic groups, but Prince William county is over 52% open space, including the Prince William Forest Park, the Manassas Battlefield Park, Quantico, and the Rural Crescent.
It appears that the USGS studies that determined an “average recharge” was based on took place at Cedar Run and Broad Run, not characteristic of the hydrogeologic group underlying Klein property and adjacent area. It is unlikely that this site in its current state recharges at the “average recharge rate for the County” and the actual recharge rate of groundwater underlying adjacent to this site needs to be determined.
Flux estimates of components of the hydrologic cycle can be made by creating a water budget in which the various components must balance. Such a water balance approach can be reasonably accurate when all of the terms in the budget can be calculated or reasonable estimated. This approach is appropriate for the scale of the entire Commonwealth, but not on a smaller scale like the Kline property and adjoining neighborhood. On a small local scale these estimates are not at all accurate or appropriate methods of determining groundwater adequacy or impact. Most accurate methods used to estimate recharge are highly dependent on local measurements in both space and time (Healy and Scanlon, 2010) this would need to be done for the Kline property and the surrounding neighborhoods to provide a high level of certainty that the availability, quality and sustainability of groundwater supplying the adjacent neighborhood wells would not be impacted .
This information is necessary to ensure that the neighbor’s water supply will not be impacted over time by the development. If the county comprehensive plan and zoning amendments go through it is essential that the neighbors be assured that their groundwater supply will be adequate to serve their wells into the future and not be depleted slowly over time.
Stanley Martin Homes has proffered to engage an environmental professional to perform a well yield and limited water quality test on any lawfully operating household water supply well for residential property located within 800 feet from the Kline property line to establish a baseline for the closest wells. Those well owners may request a re-evaluation of their well if a negative impact is suspected. If the impact is confirmed by the reevaluation then there is a procedure for the homeowner to request one of three forms of resolution within 30 days; repairing the well, drilling a new well or connecting the home to the public water system.
Sounds good; however, 800 feet which is effectively the first line of homes may not include enough area to ensure no impact. The U.S. EPA standard for determining impact is a much greater radius typically including 2.0 miles for class II a groundwater under the EPA’s Groundwater Protection Strategy. The scope to testing should be defined and include all primary and secondary contaminants regulated under the Safe Drinking Water Act. Finally, 30 days is too short to determine if a well can be repaired, identify and permit a new well site with the County Public Health Department , or determine if the home can be or should be connected to the public water supply. In addition, depletion of groundwater can be a very slow but real process and it might take years for homeowners to notice impact to their wells.
There are other concerns. There is a gas station planned for the development within 600 feet of a private drinking water well. To prevent fuel contamination of the aquifer the Sheets gas station planned for the Kline property development should have secondary containment, constant monitoring, double walled piping, tank and dispenser sumps to prevent leaks and spills and contain on the property any releases. If any of the other commercial sites or the school site will have underground fuel tanks they should be similarly equipped.
The Prince William County Watershed Management Branch found that the proposed amendment to the comprehensive plan and rezoning would negatively impact the protection of environment resources. They stated that retaining the SRR long range land use “will achieve notably greater preservation of existing land features, less impervious area and greater protection of environmental resources.” Mitigation of this impact needs to be included in the proposal for the site.
Finally, the U.S. Environmental Protection Agency, EPA, mandated a contamination limit called the TMDL (total maximum daily load for nutrient contamination and sediment) to restore the Chesapeake Bay and its watershed. About half of the 39,490 square mile land area of Virginia is drained by the creeks, streams and rivers that comprise the Chesapeake Bay watershed, including all of Prince William County.
This TMDL limits discharge of nitrogen, phosphorus and sediment from waste water treatment plants, agricultural operations, urban and suburban runoff, wastewater facilities, septic systems, air pollution and other sources in the county. To achieve this goal Virginia developed a remediation plan acceptable to the EPA called a Watershed Implementation Plan (WIP). We have reached the halfway point in the program and the EPA will evaluate the plan, goals and require a revision to meet the mandated targets. At the last evaluation point Virginia (including Prince William County) was notified that “EPA will maintain enhanced oversight for Virginia urban/suburban stormwater and will continue to monitor Virginia’s progress in closing the nutrients and sediment gap in the 2016-2017 milestone period.”
The increased nitrogen, phosphorus and sediment that will result from the change in use of the Kline property needs to calculated and accounted for. The impact of the Kline property development on the TMDL needs to be mitigated in another way if the Comprehensive plan and zoning are amended.
Stanley Martin Homes wants a Comprehensive Plan Amendment (CPA) to change the long-range land use designation for the over 100. acres from CEC, Community Employment Center, and SRR, Semi-Rural Residential, to CEC with a Center of Community Overlay and with an expanded study area. These changes would allow Stanley Martin build 329 townhomes, 63 single-family homes and 400,000 square feet of commercial space and an elementary school. The properties in the development will be connected to public water from supplied by Prince William Public Service Authority and with surface water as the source supply. So, there will be no increase in the use of groundwater in the immediate area.
The Kline Farm property encompasses a bit more than 100 acres and is generally located south and southeast of the intersection of Prince William Parkway and Liberia Avenue, and north of Buckhall Road. The property is located in a transitional area of the county that is adjacent to the City of Manassas. North of the site and across the Prince William Parkway is the Prince William Commerce Center, still under development and will contain mixed retail/commercial/office uses, as well as the suburban residential neighborhood of Arrowood and the semi-rural residential neighborhood of Hyson Knolls to the northeast. East and southeast of the site is semi-rural residential communities and A-1 zoned property. To the west and northwest is the City of Manassas with existing retail service/commercial strip development. Southwest of the subject site is existing suburban residential development.
There are important environment concerns that need to be considered. Residents within the abutting Hynson Knolls community, homeowners bordering Buckhall Road and homes along Lake Jackson Drive rely on private wells for water and septic systems for wastewater disposal. In a “Preliminary Hydrogeological Assessment-Klein Site” prepared by SES/TrueNorth they do a preliminary look at whether the development of the site is likely to have an adverse impact on surrounding private wells and septic systems. The properties in the development will be connected to public water from supplied by Prince William Public Service Authority and with surface water as the source supply. So, there will be no increase in the use of groundwater in the immediate area.
The consultants only reviewed the existing well construction records dating back about 40 years when Hynson Knolls was first developed; existing published hydrology and geology work by the U.S. Geological Survey dating to 1990 and earlier; development of a theoretical groundwater budget and a fracture trace analysis of a 1978 photograph to determining the general flow of groundwater. No physical testing of the aquifer was performed and no recent data records were used.
Private wells draw their water from groundwater. Geology, climate, weather, land use and many other factors determine the quality and quantity of the groundwater available. Within Prince William County Virginia there are four distinct geologic provinces: (1) the Blue Ridge, (2) the Culpeper Basin, (3) the Piedmont, and (4) the Coastal Plain. The U.S. Geological Survey divides the four geologic provinces of the county into seven hydrogeologic groups based on the presence and movement of the ground water calling them groups: A, B, B1, C, D, E and F. About 27 years ago the U.S. Geological Survey studied the groundwater systems within Prince William County. You can review that report if you wish to see the entirety it is by Nelms and Brokman.
The consultants for Stanley Martin Homes identify the site as located within Hydrogeological Group E. The Klein Farm and vicinity are within a fractured bedrock aquifer in which groundwater availability and flow are controlled by fractures and joints within the rock. Hydrogeologic group E consists of metasedimentary, meta-volcanic, and other metamorphic rocks. Rocks within hydrogeologic group E tend to have poor to moderate water-bearing potential, and thin- to thick cover of overburden. Ground-water storage tends to be predominantly in the overburden which is typically relatively granular and porous. This is a water table aquifer separate from but hydraulically connected to the underlying bedrock aquifer. According to that USGS report by Nelms and Brockman, some of the poorest yielding wells are located in hydrogeologic group E.
The fracture trace analysis performed by Stanley Martin Homes consultant found a predominant west-northwest to east-southeast regional fracture orientation; however, there was a notable but less prominent southwest to northeast regional fracture orientation also present. The groundwater flow in Prince William county is generally to the east-southeast, but there is considerable variation and surprises in the flow as documented by monitoring at several cleanup sites in the county and suggested by the fracture analysis.
In developing the theoretical groundwater budget the Stanley Martin Homes consultant assumed that the groundwater recharge rate for the site was equivalent to the average groundwater recharge for Prince William County. This is unlikely to be true. Not only does the geology vary across the county with different water bearing and storage potential in the different hydrogeologic groups, but Prince William county is over 52% open space, including the Prince William Forest Park, the Manassas Battlefield Park, Quantico, and the Rural Crescent.
It appears that the USGS studies that determined an “average recharge” was based on took place at Cedar Run and Broad Run, not characteristic of the hydrogeologic group underlying Klein property and adjacent area. It is unlikely that this site in its current state recharges at the “average recharge rate for the County” and the actual recharge rate of groundwater underlying adjacent to this site needs to be determined.
Flux estimates of components of the hydrologic cycle can be made by creating a water budget in which the various components must balance. Such a water balance approach can be reasonably accurate when all of the terms in the budget can be calculated or reasonable estimated. This approach is appropriate for the scale of the entire Commonwealth, but not on a smaller scale like the Kline property and adjoining neighborhood. On a small local scale these estimates are not at all accurate or appropriate methods of determining groundwater adequacy or impact. Most accurate methods used to estimate recharge are highly dependent on local measurements in both space and time (Healy and Scanlon, 2010) this would need to be done for the Kline property and the surrounding neighborhoods to provide a high level of certainty that the availability, quality and sustainability of groundwater supplying the adjacent neighborhood wells would not be impacted .
This information is necessary to ensure that the neighbor’s water supply will not be impacted over time by the development. If the county comprehensive plan and zoning amendments go through it is essential that the neighbors be assured that their groundwater supply will be adequate to serve their wells into the future and not be depleted slowly over time.
Stanley Martin Homes has proffered to engage an environmental professional to perform a well yield and limited water quality test on any lawfully operating household water supply well for residential property located within 800 feet from the Kline property line to establish a baseline for the closest wells. Those well owners may request a re-evaluation of their well if a negative impact is suspected. If the impact is confirmed by the reevaluation then there is a procedure for the homeowner to request one of three forms of resolution within 30 days; repairing the well, drilling a new well or connecting the home to the public water system.
Sounds good; however, 800 feet which is effectively the first line of homes may not include enough area to ensure no impact. The U.S. EPA standard for determining impact is a much greater radius typically including 2.0 miles for class II a groundwater under the EPA’s Groundwater Protection Strategy. The scope to testing should be defined and include all primary and secondary contaminants regulated under the Safe Drinking Water Act. Finally, 30 days is too short to determine if a well can be repaired, identify and permit a new well site with the County Public Health Department , or determine if the home can be or should be connected to the public water supply. In addition, depletion of groundwater can be a very slow but real process and it might take years for homeowners to notice impact to their wells.
There are other concerns. There is a gas station planned for the development within 600 feet of a private drinking water well. To prevent fuel contamination of the aquifer the Sheets gas station planned for the Kline property development should have secondary containment, constant monitoring, double walled piping, tank and dispenser sumps to prevent leaks and spills and contain on the property any releases. If any of the other commercial sites or the school site will have underground fuel tanks they should be similarly equipped.
The Prince William County Watershed Management Branch found that the proposed amendment to the comprehensive plan and rezoning would negatively impact the protection of environment resources. They stated that retaining the SRR long range land use “will achieve notably greater preservation of existing land features, less impervious area and greater protection of environmental resources.” Mitigation of this impact needs to be included in the proposal for the site.
Finally, the U.S. Environmental Protection Agency, EPA, mandated a contamination limit called the TMDL (total maximum daily load for nutrient contamination and sediment) to restore the Chesapeake Bay and its watershed. About half of the 39,490 square mile land area of Virginia is drained by the creeks, streams and rivers that comprise the Chesapeake Bay watershed, including all of Prince William County.
This TMDL limits discharge of nitrogen, phosphorus and sediment from waste water treatment plants, agricultural operations, urban and suburban runoff, wastewater facilities, septic systems, air pollution and other sources in the county. To achieve this goal Virginia developed a remediation plan acceptable to the EPA called a Watershed Implementation Plan (WIP). We have reached the halfway point in the program and the EPA will evaluate the plan, goals and require a revision to meet the mandated targets. At the last evaluation point Virginia (including Prince William County) was notified that “EPA will maintain enhanced oversight for Virginia urban/suburban stormwater and will continue to monitor Virginia’s progress in closing the nutrients and sediment gap in the 2016-2017 milestone period.”
The increased nitrogen, phosphorus and sediment that will result from the change in use of the Kline property needs to calculated and accounted for. The impact of the Kline property development on the TMDL needs to be mitigated in another way if the Comprehensive plan and zoning are amended.
Thursday, November 2, 2017
Emergency Disinfection of Your Well after the Flooding
Severe flooding can cause septic waste and even chemicals from
cars and factories can enter groundwater making it unsafe to drink for days or
even months depending on the extent of contamination and flow rate of
groundwater. Essentially, the water will have to clear itself through natural
attenuation (filtering by the soil and the contamination moving with the flow
of the groundwater). A well may not be a safe source of water after the flood,
but in all likelihood it will recover. Often all you need to do is flush the
well then disinfect it.
Be aware that waste water from malfunctioning septic tanks
or chemicals seeping into the ground can contaminate the groundwater for
several weeks if there was significant flooding. The first thing you need to do is respond to any
immediate problems and then test the water periodically to verify the continued
safety of drinking water.
Unless your well was submerged near a trucking depot, gas station or other industrial or commercial source of chemicals it is likely that torrential rains or flood waters have infiltrated your well and you have “dirty or brownish” water from surface infiltration. This is especially true if you do not have a sanitary cap on your well or have a well pit. Historically, it was common practice to construct a large diameter pit around a small diameter well. The pit was intended to provide convenient access to underground water line connections below the frost line. Unfortunately, wells pits tend to be unsanitary because they literally invite drainage into the well creating a contamination hazard to the water well system. It is most likely if your yard was flooded or your well submerged that you have some surface infiltration of water. In that case, chlorine shocking your well should disinfect your well and last at least 7-10 days.
Unless your well was submerged near a trucking depot, gas station or other industrial or commercial source of chemicals it is likely that torrential rains or flood waters have infiltrated your well and you have “dirty or brownish” water from surface infiltration. This is especially true if you do not have a sanitary cap on your well or have a well pit. Historically, it was common practice to construct a large diameter pit around a small diameter well. The pit was intended to provide convenient access to underground water line connections below the frost line. Unfortunately, wells pits tend to be unsanitary because they literally invite drainage into the well creating a contamination hazard to the water well system. It is most likely if your yard was flooded or your well submerged that you have some surface infiltration of water. In that case, chlorine shocking your well should disinfect your well and last at least 7-10 days.
If your water is brown, the first thing you should do is run your hoses (away from your septic system and down slope from your well) to clear the well. Run it for an hour or so and see if it runs clear. If not let it rest for 8-12 hours and run the hoses again. Several cycles should clear the well. What we are doing is pumping out any infiltration in the well area and letting the groundwater carry any contamination away from your well. In all likelihood the well will clear of obvious discoloration. Then it is time to disinfect your well. This is an emergency procedure that will kill any bacteria for 7 to 10 days.
After 10 days you need to test your well for bacteria to
make sure that it is safe. Testing the well for bacteria would determine if the
water were safe to drink. A bacteria test checks for the presence of total
coliform bacteria and fecal coliform bacteria. These bacteria are not normally
present in deeper groundwater sources. They are associated with warm-blooded
animals, so they are normally found in surface water and in shallow groundwater
(less than 20-40 feet deep). Most bacteria (with the exception of fecal and
e-coli) are not harmful to humans, but are used as indicators of the safety of
the water.
To disinfect a well you will need common unscented household bleach. For a typical 6 inch diameter well you need 2 cups of regular laundry bleach for each 100 foot of well depth to achieve about 200 parts per million chlorine concentration. You will also need rubber gloves, old clothes and protective glasses to protect you from the inevitable splashes, and don't forget a bucket to mix bleach with water to wash the well cap.
To disinfect a well you will need common unscented household bleach. For a typical 6 inch diameter well you need 2 cups of regular laundry bleach for each 100 foot of well depth to achieve about 200 parts per million chlorine concentration. You will also need rubber gloves, old clothes and protective glasses to protect you from the inevitable splashes, and don't forget a bucket to mix bleach with water to wash the well cap.
- Put on the old clothes and safety glasses
- Run your hoses from the house to the well
- Fill bucket with half water and half chlorine.
- Turn off power to the well
- Drain the hot water tank
- Remove well cap
- Clean well cap with chlorine and water solution and place in clean plastic bag
- Clean well casing top and well cap base using brush dipped in chlorine water
- Pull wires in the well aside if they are blocking the top of the well and clean them with a rag dipped in chlorine water mixture. Make sure there are no nicks or cuts in the wires.
- Put the funnel in the well top and pour in the chlorine and water mixture
- Now pour in the rest of the chlorine SLOWLY to minimize splashing
- Go back to the basement and turn the power to the well back on
- Turn on the hose and put it in the well
- Sit down and wait for about 45 minutes or an hour
- After 45 minutes test the well to make sure that the chlorine is well mixed
- Use the hose to wash down the inside of the well casing
- Turn off the hose
- Carefully bolt the well cap back in place
- Now go back into the house
- Fill your hot water heater with water
- Draw water to every faucet in the house until it tests positive for chlorine then flush all your toilets. Turn off your ice maker.
- Then do not use the water for 12-24 hours
- Set up your hoses to run to a gravel area or non-sensitive drainage area. The chlorine will damage plants
After 16 hours turn on the hoses leave them to run for the
next 6-12 hours. The time is dependent on the depth of the well and the
recharge rate. Deeper wells with a faster recharge rate take longer. If you
cannot run your well dry and it recharges faster than the hoses use water you
will need to keep diluting the chlorine. If you can run your well dry, you
might have to let it recharge and run the water off again to clear the
chlorine.
After about 6 hours of running the hoses begin testing the water coming out of the hose for chlorine. Keep running the hose and testing the chlorine until the chlorine tests below about 1 ppm.
- Drain the hot water heater again, open the valve to refill it and turn it back on
- Open each faucet in the house (one at a time) and let run it until the water tested free of chlorine. Be aware the hot water will sputter- big time- until all the air is out of the system. Flush all the toilets
- Change the refrigerator filter cartridge and dump all your ice and turn your ice maker back on.
It is important not
to drink, cook, bath or wash with this water during the time period it contains
high amounts of chlorine whose by products are a carcinogen. Run the water
until there is no longer a chlorine odor. Turn the water off. The system should
now be disinfected, and you can now use the water for 7 to 10 days when the
effects of the disinfection wear off. Hopefully, a single disinfection
will be enough.
Unlike public water systems, private systems are entirely unregulated; consequently, the well testing, and treatment are the voluntary responsibility of the homeowner. Virginia Master Well Owner Network (VAMWON). volunteers can help simplify understanding the components of a well and private drinking water system. The VAMWON volunteers and agents can provide information and resource links for private well owners and inform Virginians dependent on private water systems about water testing, water treatment, and system maintenance. You can find help in Virginia or my contact information through this link by entering Prince William County or my name in the search box. I am happy to answer emails.
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