Thursday, May 26, 2016

Finally, Chemical Safety Act Set to Pass

On Tuesday, May 24th by a vote of 403-12 the U.S. House of Representative passed the Frank R. Lautenberg Chemical Safety for the 21st Century Act. This bill amends the Toxic Substances Control Act (TSCA), a 1976 law that provides the U.S. Environmental Protection Agency (EPA) with the limited authority they have to require reporting, record-keeping, testing, and restrictions on chemical substances, mixtures and compounds. Both the House and Senate passed different versions of this bill last year that have now been reconciled. The current version of the bill goes to the U.S. Senate where it is expected to pass this week.

Chemicals are everywhere, they exist in pharmaceuticals, household products, personal care products, plastics, pesticides, industrial chemicals, human and animal waste; they are in short, all around us. These chemicals include organics, inorganic, polymers, and UVCBs (chemical substances of Unknown or Variable composition, Complex reaction products, and Biological materials). Yet, very few of these chemicals have been evaluated for health risks under the existing TSCA law because the EPA can only require testing for existing chemicals when there is evidence of harm and this became a sort of Catch 22: you can’t require testing unless there is evidence of harm and you can’t prove evidence of harm without testing. Under TSCA, if a chemical is on the TSCA Inventory of over 80,000 chemicals, the substance is considered an "existing" chemical.

The Frank R. Lautenberg Chemical Safety for the 21st Century Act would require the EPA to test chemicals using "sound and credible science" and impose regulations if they are shown to pose a health risk. The bill revises TSCA to create a safety standard to ensure that no unreasonable risk of harm to health or the environment will result from exposure to a chemical under the conditions of use. The standard includes the protection of potentially exposed or susceptible populations, but does not take cost or other non-risk factors into consideration. The bill repeals the requirement that the Environmental Protection Agency (EPA) apply the least burdensome means of adequately protecting against unreasonable risk from chemicals.

In addition, the bill revises the EPA's authority to require the development of new information about a chemical by establishing a risk-based screening process. By deadlines specified in the bill, the EPA must designate a certain number of existing chemicals as high- or low-priority for safety assessments and determinations and conduct safety assessments and determinations for high-priority chemicals.

The bill requires that the EPA prevent the manufacture, processing, use, distribution, or disposal of a new chemical, or a significant new use of an existing chemical, if the chemical is not likely to meet the safety standard, or additional information is necessary to make a safety determination. The bill requires manufacturers and processors to pay fees to defray the costs of this bill and establishes the TSCA Implementation Fund to receive such fees.

Out of thousands upon thousands of chemicals in commerce today, very few have been fully evaluated for potential health effects. Until recently when screening assays became available it was impossible. Now, with the analytical tools of the 21st century this has changed. Scientists can now use screening assays to evaluate the potential health effects of thousands of chemicals to choose the ones to look at further to consider regulating. This screening uses automated methods that allow for a large number of chemicals to be rapidly evaluated for a specific type of biological activity.

In anticipation of this regulation, EPA in conjunction with the National Institutes of has been trying to improve the data generated from the automated screening technology to incorporate chemical metabolism. Current technology would miss chemicals that are metabolized to a more toxic form in the body where impact could be magnified. EPA is working with the science community to find new ways to incorporate physiological levels of chemical metabolism into screening assays. Using both prestige and modest cash awards the EPA announced a new challenge that will award in total up to $1 million to improve the data generated from automated chemical screening technology used for toxicity testing

Monday, May 23, 2016

What We Found in the Water Wells of Prince William County in 2016


As part of the Virginia Household Water Quality Program the Virginia Cooperative Extension (VCE) holds an annual subsidized drinking water clinics for well owners. This year samples were analyzed for: iron, manganese, nitrate, lead, arsenic, fluoride, sulfate, pH, total dissolved solids, hardness, sodium, copper, total coliform bacteria and E. Coli bacteria at a cost of $55 to the well owner. These 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 we found in the 65 private wells tested in Prince William County in 2016.

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, 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. Primary standards are ones that can impact health and from the tested substances include: coliform bacteria, E. coli bacteria, nitrate, lead, and arsenic.

As in last year, the 2016 Prince William County water clinic found that almost a quarter of the wells tested present for coliform bacteria-this was a lower percentage than the overall program finds. 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.

None 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 work 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 65 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.

In years past the water clinic has found almost 20% of wells tested positive for lead. This year we had 13.8% of homes have first flush lead levels above the SDWA maximum contaminant level of 0.015 Mg/L. After the first flush 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, all but one case lead were the concentrations negatively correlated with pH values. Houses built before 1988 when the ban on lead went into effect and had low pH water had 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. It is important to note that elevated lead concentrations were still observed in homes built after 1988 and in one home with normal pH and built after 2000.

Iron and manganese are naturally occurring elements commonly found in groundwater in this part of the country. 9.2% of the wells tested exceed the iron standard and 1% 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 are easily 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, 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. 21.5% of the wells tested were found to have acidic water this year. High pH levels are not natural to groundwater and typically result from salt water intrusion or over treatment with water softening system and/acid neutralizing systems. There was one home where this turned out to be the case.

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, 22% of the wells had hard water exceeding that level. This year we had a well test at 346.8 mg/L, but overall on 15.4% 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.

For the second time this year we found a well 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 Prince William County. Arsenic can also be an indication of industrial or pesticide contamination and further testing should be done. 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, iron oxide filter system, or maybe a water softening system.

Thursday, May 19, 2016

Groundwater of Prince William County

from USGS
About 25 years ago the U.S. Geological Survey studied the groundwater systems within Prince William County, Virginia. The following is based on that report.

Private wells draw their water from groundwater. Geology, climate, weather, land use and many other factors determine the quality of the groundwater. 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.

The quantity and quality of ground water in Prince William County varies across the county depending on the geologic and hydrogeologic group you are in. The rocks in the Blue Ridge, Piedmont, and Coastal Plain contain minerals that are resistant to weathering, and the ground water tends to be acidic having low concentrations of dissolved constituents. Generally, ground water is soft (slightly acidic) to moderately hard in the Blue Ridge, Piedmont, and Coastal Plain and soft to very hard in the Culpeper Basin. Hydrogeologic group A is within the Blue Ridge formation; hydrogeologic groups B, B1, and C are in the Culpeper Basin; hydrogeologic groups D and E are in the Piedmont; and hydrogeologic group F includes unconsolidated material of the Coastal Plain and overburden in the other provinces.

Hydrogeologic group A underlies the northwestern part of Prince William County on Bull Run Mountain, which is part of the Blue Ridge geologic province, and consists of Early Cambrian metasedimentary rocks. Because of the thin to absent cover of overburden, ground-water storage predominantly is in the fractures in the bedrock. Areas underlain by Quaternary mountain-wash deposits along the base of Bull Run Mountain may have ground water stored in these deposits.

Hydrogeologic group B underlies the western part of Prince William County and consists of sedimentary rocks of the Culpeper Basin. The predominant rock types are conglomerates, sandstones, siltstones, shales, and argillaceous limestones. Rocks within hydrogeologic group B tend to have moderate to excellent water-bearing potential because it is a fractured rock system with very little overburden. The highest reported yields in the county are from wells located in this hydrogeologic group B and this is where I bought a house. The downside is that the hydrogeologic group is susceptible to contamination- the fractures that carry water can easily spread a contaminant and without adequate overburden spills could flow to depth through a fracture.

Hydrogeologic group B1 is a subset of group B with similar rock types, structure, and water-bearing potential; except that B1 is beneath group B at 500 feet below grade and evaporitic minerals tends to increase at depths. The predominant mineral is gypsum (CaSO4) though it does not appear to impact taste.

Hydrogeologic group C, which is interspersed throughout the area of groups B and Bl, in the western part of the County, consists of igneous rocks (basalt and diabase) of the Culpeper Basin. The rocks of group C are Early Jurassic in age. The predominant rock types are basalt, sandstone, siltstone, diabase, hornfels, and granofels. Rocks within hydrogeologic group C tend to have generally poor water-bearing potential because of the wide spacing between fractures, mineralization of fractures, and random fracture orientations. In other words, unless you hit a good fracture, you are likely to have a dry well and these wells tend to become mineralized and loose flow over time. The best wells are in the basalt.

Hydrogeologic group D is located within the Piedmont formation and consists of three igneous plutons in the eastern part of Prince William County: the Goldvein, Lake Jackson, and Occoquan Plutons. Rocks within hydrogeologic group D tend to have moderate water-bearing potential and ground-water storage tends to be predominantly in the overburden. Wells in this area are most susceptible to drought and tend to be slightly acidic.

Hydrogeologic group E is also in the Piedmont formation in the eastern part of the county, and consists of metasedimentary, metavolcanic, 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. Similar to the rocks of hydrogeologic group D, ground-water storage tends to be predominantly in the overburden. Some of the poorest yielding wells are located in this hydrogeologic group.

Hydrogeologic group F is an approximately 5 mi in width, at the very eastern edge of Prince William County. This area is east of the Fall Zone in the Coastal Plain. The geology consists predominately of sand, silt, clay, lignite, gravel, soil, and weathered bedrock. Because of the sand and gravel this area tends to have very good to excellent water-bearing potential and wells in the Potomac Formation of the Coastal Plain tend to have high yields. There is a possible interconnection between the aquifers and the Potomac River.

Generally speaking, the groundwater in the county is recharged in elevated areas between stream valleys and channels and discharges to streams and estuaries. The paths and duration of groundwater flow are different between consolidated rocks and unconsolidated material. Groundwater in the consolidated rocks flows through the system of fractures following a circuitous path before discharging to a stream or estuary. In unconsolidated material, ground water generally follows a direct path from the recharge area to the discharge area. Well yields tend to be highest in the rocks of hydrogeologic groups B and B1, which can be attributed to the closely spaced fractures, joints, and bedding-plane of this fractured rock system. This area is most likely to produce a reliable and water rich well. Well yield in hydrogeologic group C range widely with the best yield coming from the basalt..



Monday, May 16, 2016

Private Wells and Health Risks in Your Drinking Water

Private wells do not fall under the regulatory authority of the U.S. Environmental Protection Agency (EPA) or the Safe Drinking Water Act. In the past it was always assumed that groundwater that supplies private wells is fairly safe and clean. However, recent research by the U.S. Geological Survey and studies of water borne disease outbreaks associated with untreated groundwater have found that private wells, springs and cisterns are a potential source of elevated health risk. In addition, while waterborne disease outbreaks overall have fallen since 1971, the waterborne disease outbreaks in private well systems continues to increase relative to public systems.
This is of concern because according to the EPA, approximately 15% of U.S. households, more than 47 million people get their drinking water from private wells and springs.

Preliminary efforts to survey water quality in private systems in limited studies in Pennsylvania, Wisconsin and Virginia report that 23−58% of wells tested in their studies exceed at least one safe drinking water act health-based standard. However, since 2010 Virginia has been operating the subsidized well water testing clinics as part of the Virginia Household Water Quality Program testing wells throughout Virgininia. The goal of the Virginia Household Water Quality Program is to educate well owners, improve the water quality and protect the health of Virginians with private water supplies, such as wells, springs and cisterns. In 60 of Virginia’s 95 counties more than half the households rely on private wells, springs, and cisterns. In total there are more than 1,500,000 households in Virginia with private water supplies.

The Virginia Cooperative Extension obtained a grant from the U.S. Department of Agriculture’s Cooperative Research Education and Extension Service to restart the Virginia Household Water Quality Program originally launched in 1989. Working with the researchers at Virginia Tech the program has used the data they have collected to identify characteristics in wells within counties and throughout the Commonwealth. In the 2012 clinics analysis for lead and copper were added. Participation in the drinking water clinics is voluntary and though the analysis is subsidized, participants are still charged a fee, currently $55. Homeowners who wish to participate have to hear about the clinic, show up for two meetings, purchase a water sampling kit with instructions and are asked to fill out a questionnaire about system characteristics, perceived water quality and household demographics and drop off their samples on time on the scheduled day. Typically, better educated and more affluent households participate.

The scientists at Virginia Tech have used the data from the 2012 clinics and targeted additional field study to examine, lead in drinking water from private wells. The following information is from their recent paper cited below.
Of the 2,146 samples taken in an 18 month period from spring 2012 to fall 2013, 58% of the wells sampled exceeded at least one Maximum Contaminant Level (MCL) from the EPA’s safe drinking water act’s levels though only 14 of the 82 parameters were tested. Bacterial contamination was the most common issue, with 46% of systems testing positive for total coliforms with 10% having E. coli present. The most common treatment systems were water softeners which are used to treat hard water, elevated iron and manganese which were found to be less prevalent that water softener sales would indicate.

Using the action level for lead and copper as a threshold, 19% of the tested systems had elevated lead concentrations (15 μg/L) and 12% had elevated copper concentrations (1.3 mg/L) in the first draw. Lead leaches into water primarily as a result of corrosion of plumbing and well components. Corrosion control techniques such as adjusting pH or alkalinity that are commonly used in public systems are not common in private wells where the decision to install and maintain treatment is solely the prerogative and responsibility of the homeowner. As a result, though 26% of the private wells had pH outside the neutral range of 6.5-8.5 (and 89% of these were below 6.5), only 5% of private well systems had acid neutralizers installed to control pH and corrosion within the home and 3% had reverse osmosis units that could remove lead among other contaminants. 

The scientists did not find a correlation between self-reported well depths and lead concentrations, but lead concentrations were negatively correlated with pH values. The lower the pH (more acidic the water) the higher the lead concentrations found. Houses built before 1988 when the ban on lead went into effect had higher lead concentrations; however, it is important to note that elevated lead concentrations were still found in homes built after 1988. The scientists attributed this to the presence of lead in brass fixtures and faucets. If that is correct, then with the ban on lead containing materials in the Reduction of Lead in Drinking Water Act, lead release from brass components should be reduced in the future.

For most of the private well supplied systems sampled in this study, flushing for 5 minutes reduced lead concentrations below 15 μg/L. However, 2% of households experienced an increase in lead concentrations with flushing suggesting that there may be other components within the well and plumbing system that release lead and/or particulate lead and may have been mobilized. To develop effective remediation and prevention additional work must be done to increase our understanding of the mechanisms of lead release in well systems. Brass fittings and components within the well might be the source of soluble or particulate lead.

Pieper, Kelsey J.; Krometis, Leigh-Anne H. ; Gallagher Daniel L; Berham, Brian L.; and Edwards, Marc; Incidence of waterborne lead in private drinking water systems in Virginia; Journal of Water and Health; 13.3 2015. Pages 897-907.

Thursday, May 12, 2016

Brood V of the 17 Year Cicadas are Emerging in the Mid-Atlantic Region


Many call periodical cicadas "17-year locusts" or "13-year locusts", but they are not the locusts of the Egyptian Exodus, which are actually a type of migrating grasshopper. However, if you live in the area if this year’s emergence, when the 17 year cicadas arrive in the next several days it may indeed feel like a plague. In Virginia there are seventeen broods of the 17-year cicada and thirteen broods of the 13-year cicada. Every year they will emerge somewhere in the state, but unlike 2013 this one is modest in the Commonwealth. This citizen scientists in Maryland have already reported the emerging brood called Brood V, and though I am out of the “designated area” I saw a couple this morning.

Some counties in Virginia have several broods that impact all or part of the county. The 2013 emergence was huge in this region and impacted Loudoun, Prince William, Fairfax and Fauquier. The Magicicada Brood V that is emerging this year is much smaller in this region.

The 17 year periodical cicadas or Magicicada adults have black bodies, red eyes and orange wing veins, with a black "W" near the tips of the forewings. They look much scarier than they are in reality- they are mostly harmless and are a favorite of amateur entomologists. The annual Cicada or dog day cicada are related to the periodical cicada. As their name implies appear every summer during the long, hot dog days of July and August. Those cicadas have two- to five-year life cycles, but their broods overlap and some appear every summer. That is not the Cicadas that are now emerging from the ground.
from VA Tech


Right now mature nymphs are emerging from the soil and climbing onto nearby vegetation and other vertical surfaces. They then molt to the winged adult stage. The emergence is tightly synchronized, with most adults appearing within a few nights. Adult cicadas live for only two to four weeks. When the 17 year periodical cicadas emerge the density can be shocking and noisy. It is common to have tens to hundreds of thousands of periodical cicadas per acre, but there are records of up to a million and a half periodical cicadas. Half of the cicadas are “singing.” Male cicadas sing quite loudly by vibrating membranes on the sides of their abdominal segment. Male songs and choruses are a courtship ritual to attract females for mating. The males’ choruses have been known to drive people to distraction-stay inside with the windows closed and if need be use a fan for white noise- it will be over soon. After mating, females lay their eggs in narrow young twigs slicing into the wood and depositing up to 400 eggs in total for each female in 40 to 50 locations each.

It is the egg laying that does most of the damage associated with periodical cicadas. Cicada eggs remain in the twigs for six to ten weeks before hatching. The nymphs do not feed on the twigs. The newly hatched, ant-like nymphs fall to the ground where they burrow 6 to 18 inches underground to feed on roots. Mature trees and shrubs usually survive even dense emergences of cicadas without long term damage, possibility even benefiting from pruning some lower twigs and braches. However, in the summer of a large emergence like 2013 around here many deciduous trees turn brown due to the breakage and death of peripheral twigs caused by the females laying their eggs and the emergence of the nymphs. Only young trees are usually permanently damaged and that is because so much of these trees are small twigs and branches. In 2013 I planted too early and lost a few new trees.

Apparently because of their long life cycles and the synchronization of their emergence, periodical cicadas do not have natural population control by predators, even though everything from birds to spiders to snakes to dogs eats them opportunistically when they do appear. The massive emergence is believed to overwhelm predators and most of the periodical cicadas survive to mate and reproduce that is the whole point of the emergence. Cicadas are not poisonous and do not have a stinger. Their survival and expansion strategy is based purely on numbers.

Monday, May 9, 2016

Coal Ash Water Treatment Begins at Possum Point


This morning, May 9th 2016 Dominion Power was scheduled to begin operation of the $35 million portable Water Treatment Plant at Possum Point. If you recall, Dominion Power has been moving forward with a plan to “close in place” 3.7 million cubic yards of coal ash under the recently finalized U.S. EPA Coal Ash regulation. The plan for Possum Point is to consolidate all of the on-site coal ash into one impoundment. There is estimated to be 3.7 million cubic yards of coal ash. Dominion has collected more than 1 million cubic yards of ash from four smaller ponds, put them in a 120-acre pond that already contains 2.6 million cubic yards of coal ash that they will dewater. Ultimately, the pond will be capped with an impermeable membrane to prevent future infiltration of rain.

These coal ash ponds have been open to the elements and taking on water for decades. Trace contaminants and metals in the coal ash may have already leached into the groundwater, Quantico Creek and Potomac. The State Water Control Board and Virginia Department of Environmental Quality (DEQ) are the regulating agencies that oversee the dewatering of the ponds, though the U.S. EPA maintains authority to review applications and permits for "major" discharges, a distinction based on discharge quantity and content. In January 2016 DEQ and the Water Control Board approved the modifications to Dominion’s Virginia Pollutant Discharge Elimination System (VPDES) Permit allowing the treatment and subsequent discharge of the coal ash waters to Quantico Creek, which flows into the Potomac River.

from Dominion Power


The water treatment process begins with aeration. Water is pumped from one of the coal ash ponds into an aerator. Adding oxygen to the water helps the treatment process by separating coal ash particulates in the water.

Chemicals are added to the water, to adjust the pH cause the coal ash sediment to coagulate. The pH is a measure of acidity in the water. Decreasing the acidity of the water encourages particles in the water to settle and polysaccharides act as a coagulant. The chemicals allow the coal ash sediment to bond to form a mass that can be easily removed from the water.

The water is passed through a series of ever finer filters called Geotubes, to remove the particles. Water then flows into a Geotube that separates coal ash sediment from the water and removes them. The water moves onto the next Geotube in the series until all the sediment has been removed. Dewatered sediment from the Geotubes will be hauled away by truck and properly disposed of. Following this filtration the water flows into sand filters where more coal ash sediment is trapped.

Then the water is tested and pumped into holding tank where it will be held until the test results are confirmed. If certain constituents remain at or near trigger levels, then the enhanced treatment will be is used to remove them. The water will be pumped back from the holding tank into a large series of tanks where a process called “weak acid cation exchange” occurs, and the water is treated again.

Because they decreased the acidity of the water at the start of the treatment process, it may need to be readjusted to levels that are safe for the river. After the testing process is complete and the water is tested and confirmed to be safe for the environment, aquatic life and the community, the water will be released into Quantico Creek.

GAI Consulting will collect samples of the filtered water every hour. Pace Analytical Services will then analyze the samples. Dominion will be posting the test results on their web site so that you can monitor the remediation process if you are so inclined at www.dom.com/coalash .
from Dominion Power Richmond cleanup


It will take a 11-12 months to treat the water in the ponds. Dominion Power’s plan is to move the remaining 200,000 cubic yards of coal ash from ponds A, B, C, and E to Pond D once the dewatering process is complete. Then the ponds will be covered with high density polyethylene caps, commonly known as a clay caps followed by two feet of soil and vegetation on top of the caps. All five ponds will be monitored for groundwater leaks following the closures. Pond D, the only pond that will still contain coal ash will be monitored for 30 years.

Thursday, May 5, 2016

Antibiotic Resistance and the Last Line of Defense

Last December in an article published in the Lancet it was reported that E. coli bacteria worldwide are sharing a gene that confers resistance to an antibiotic called colistin one of the rarely used so called last resort antibiotics in the polymyxin family. Until now antibiotic resistance had developed as a result of chromosome mutation, not gene transfer. Now, antibiotic resistance was observed and documented as a result of a gene transfer. This was discovered during a routine surveillance project on antimicrobial resistance in E. coli bacteria from food animals in China where a major increase of colistin resistance had been observed. They found that an E coli strain that had colistin resistance could be transferred to another strain. Though viruses had been known to transfer properties this way, it had not been observed in bacteria.

The researchers believe that their finding of a colistin resistance that is transmissible among bacteria will result in rapid transmission of the resistance and the progression of extensive drug resistance to pan-drug resistance- meaning there is no effective treatment available. This is a frightening prospect of potential global significance. The consequences of this resistant gene spreading will result in increased deaths.

Although in modern, well-funded healthcare systems, obtaining access to second and third-line treatments may not be an issue, mortality rates for patients with infections caused by resistant bacteria are significantly higher, as are their costs of treatment. And we are seeing in parts of Europe and the United States an increasing number of patients in intensive care units, haematology units and transplant units who have pan-resistant infections. The death toll from resistant bacteria in the United States, Great Britain and Europe is estimated at 50,000 per year, but is for cast to grow by a power of 10 by 2050.

Antibiotics were discovered in the early part of the 20th century and went on to revolutionize healthcare, becoming the bedrock of many of the greatest medical advances of the 20th century. Common yet frequently deadly illnesses such as pneumonia and tuberculosis (TB) could be treated effectively. A small cut no longer had the potential to be fatal if it became infected, and the dangers of routine surgery and childbirth were vastly reduced. But bacteria and other pathogens have always evolved so that they can resist the new drugs that medicine has used to combat them. Resistance has increasingly become a problem in recent years because the pace at which we are discovering novel antibiotics has slowed drastically, while antibiotic use is rising. Massive amounts of antibiotics are routinely used prophylactically in agriculture, and to increase weight gain in farm animals.

Colistin was developed in the 1950s, one of a class of compounds called polymyxins. It is known as a last resort drug — physicians avoid using it when possible — because it tends to damage patients’ kidneys. As a consequence, bacteria have been slow to develop resistance to colistin, compared to other antibiotics, and it has become in many cases of resistant bacteria the last line of defense. In the China study polymyxin resistance was shown to be entirely due to the plasmid-mediated MCR-1 gene.

In December it was believed that MCR-1 was confined to China, but now a new study published on April 28th 2016 found that MCR-1 is present in South America where colistin resistance was investigated in 4,620 Enterobacteriaceae isolated from human, animal, food and environmental samples collected from 2000 to 2016. Enterobacteriaceae are a large family of bacteria that includes such pathogens as Salmonella, E. coli, Yersinia petis, Klebsiella and Shigella and others. They found that MCR-1-positive Enterobacteriacae have been emerging in South America since at least 2012. This finding supports a previous report on the possible acquisition of MCR-1-harbouring E. coli by European travelers visiting Latin American countries.

The rapid pace that other mechanisms of drug resistance spread indicates that, with the transmissible colistin resistant gene, progression of Enterobacteriaceae from extensive drug resistance to pan-drug resistance is inevitable and will ultimately become global. The discovery of the emergence of transmissible resistance in the form of MCR-1 is a finding of global significance. Wash your hands, keep outdoor shoes, clothing and backpacks in the mudroom and away from the rest of the house.