Thursday, September 29, 2016

Genetically Modified by Government Standards

The changes in genetic science that have taken place in just the last few years have taken my breath away. In 2011 and 2013 new methods of genome editing appeared. Genome editing is the act of modifying, inactivating, replacing or removing a gene using and engineered protein to cut DNA at a precise location. The newest methods are called TALEN (Transcription Activator-Like Effector Nucleases) and CRISPR (Clustered Regulatory Interspaced Short Palindromic Repeats)/Cas9 systems.

This is not my field so I will leave the explanations to others, but these systems that can be ordered from a laboratory supply house have proved to be effective and reliable tools for tightly targeted genome engineering by cutting out or activating existing DNA. The CRISPR/Cas9 system has been hailed as a game changer for its simplicity to use and have proved to be an effective and reliable tools for genome engineering. However, the CRISPR technology is mired in intellectual property disputes. Ownership of TALENs is clearly defined and reportedly TALENs is can be better at hitting an exact location in the genome and making clean cuts in DNA. One of the co-inventors of TALENs is developing and extensive set of CRISPR tools for facilitating its use in plant laboratories.

In the United States these tools are being widely used to modify plants and crops to improve yield, make plant more drought resistant, blight and disease resistant, improved shelf life of produce, even produce soybeans with reduced trans fats in the oil. Surprisingly, the U.S. Department of Agriculture (USDA) has so far exempted plants altered by TALENS and CRISPER from being classified as “Genetically Modified, (GM).” The USDA’s existing rules on genetic modification focus on whether a plant contain “foreign” DNA from a plant pest or pathogen. These regulations were developed two decades ago when “gene guns” were used to insert new genes into plants. So far, the USDA has ruled that crops in which TALENs and CRISPR gene editing has eliminated DNA bases are not GM. No decision has yet been made on crops where TALENs and CRISPR methods have been used to introduce, replace or add genes.

Older techniques were crude, they relied on injecting a gene for a desired trait and hoping it would land at a spot on the genome where it could be active. Developing, testing and getting regulatory approval for a plant modified in this way could take decades and cost up to $100 million. This limited the development of genetically modified plants to large companies and commodity crops. The USDA exemptions for TALENs and CRISPR edited plants allows small companies to develop food products from gene edited plants.

The European Union has postponed its decision on whether or not to label TALENS and CRISPR edited plants as Genetically Modified or not. Canada labels all plants that have had a novel trait introduced by any method. The USDA has focused their rules on whether a plant contains “foreign” DNA. Scientists who favor plant modification argue that TALENs and CRISPR are merely a faster way to “bred” a desirable trait in a plant. They see the USDA standard is appropriate since TALENs and CRISPR leave no DNA behind so that the resulting plant should be indistinguishable from plants that with enough time could be naturally bred. However, is it honest to not label these plants, crops and the resulting food products as resulting from modified plants; or is the fact that mankind has been modifying plants using selective breeding for thousands of years make labeling moot? You decide.

DuPont (a company I once worked for) is a leader in the CRISPR area, with about 60 patents and applications and more than 30 published scientific articles. The company uses CRISPR in at least two distinct ways:
  1. DuPont Nutrition & Health uses the native CRISPR-Cas system to select, through what they describe as “a fully natural process,” bacteria that are immunized against bacteriophages. The natural immunization process does not involve gene editing technologies. The use of starter cultures containing such immunized bacteria ultimately improves the quality and safety of fermented dairy foods. 
  2. DuPont Pioneer utilizes CRISPR-derived tools for genome editing applications. The genome editing technology is capable of making exact changes to the DNA of many organisms. In plants, this editing capability can be applied to promote drought tolerance and disease resistance to protect plant health and increase crop yields. It also can eliminate food allergens and improve the nutrient composition of plant-derived oils.DuPont Pioneer plans a CRISPR altered version of its “waxy corn” that was deemed by the USDA to not be “genetically modified.”

Monday, September 26, 2016

Dry Weather Helps Lower Pollution in Chesapeake Bay

According to tributary measurements and computer modeling the amount of nitrogen, phosphorus and sediment pollution flowing into the Chesapeake Bay fell significantly between 2014 and 2015. The U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency’s Chesapeake Bay Program Office attribute this drop in pollution mostly to dry weather that produced below-normal river flows, but believe that regional efforts to reduce this pollution under the EPA mandated “pollution diet” also contributed to the reduction. Ongoing studies do show that “best management practices”—including upgrading wastewater treatment plants and reducing runoff from farmland—have lowered nitrogen, phosphorus and sediment in our regional waterways. However, the effect of weather is much stronger.

The Chesapeake Bay Program tracks nitrogen, phosphorus and sediment pollution in the Chesapeake Bay and its tributaries as it monitors the states’ performance under their plans to comply with the EPA mandate. According to data from the USGS and Chesapeake Bay Program between 2014 and 2015, total nitrogen loads fell from 290 million pounds to 217 million pounds. Phosphorus loads fell from 17.7 million pounds to 9.9 million pounds. Sediment loads fell from 7.2 billion pounds to 2.9 billion pounds.

That is a huge reduction and sounds great, but a lot of this improvement is due to a low lower than average rainfall. There is a direct relationship between rainfall and nitrogen, phosphorus and sediment pollution. The more and harder it rains the more soil and nutrients are washed into rivers. The USGS attempts to normalized the flow data before they look at the long term  trends in the data. However, "normalization" could distort the data if river flows are changing. The USGS monitors nitrogen, phosphorus and sediment loads entering the Chesapeake Bay from the nine largest rivers in the watershed. Together, pollution loads computed at all nine River Input Monitoring (RIM) stations reflect pollution loads delivered to the Bay from almost 80% of the watershed. They use an algorithm to estimate the total nitrogen, phosphorus and sediment loads delivered to the Bay in a given water year.

The long-term trends in nitrogen are improving at six of the nine monitoring stations, including those on the Susquehanna, Potomac, James and Rappahannock (the largest rivers in the watershed). Long-term trends in phosphorus and sediment, however, are more variable: phosphorus is improving at three monitoring stations and getting worse at five monitoring stations, while sediment is improving at three stations and degrading at four. It is puzzling why despite all the efforts by the Chesapeake Bay States that sediment and phosphorus are getting worse overall.

As Scott Phillips, Chesapeake Bay Coordinator, for the USGS, pointed out “While the lowered amount of pollution entering the Chesapeake Bay in 2015 is encouraging, the trends of nutrients and sediment over the last decade in the major rivers flowing into the Bay show mixed results. There will need to be improving trends in all of these rivers to support improvement in the Bay’s health.”

While continued improvements in water quality will take time, the EPA says the ecosystem is beginning to respond to protection and restoration efforts. Unfortunately, not fast enough for the regulators. In June, the EPA released its two-year milestone evaluations of how the states are progressing towards meeting the requirements of the “pollution diet.” The EPA mandate to the states calls for all needed pollution control measures to be in place by 2025, with measures that would achieve 60% of pollution load reductions in place by 2017. This is all measured by computer simulations which show that the states are behind. According the the EPA evaluation, measures are in place to achieve 31%of the nitrogen reductions, 81% of the phosphorus reductions and 48% of the sediment reductions necessary to reach the mandated targets.

Thursday, September 22, 2016

It's SepticSmart Week

This week is the U. S. Environmental Protection Agency (EPA) fourth annual SepticSmart Week to encourage the more than 26 million homeowners and communities with septic systems to properly maintain their septic systems.

When homeowners flush and don’t think about their home’s septic system, it can lead to system back-ups and overflows, surfacing sewage in your yard which can be expensive to fix, polluted local waterways, and risks to public health and the environment. Yet, Virginia like many states has struggled to get homeowners to consistently maintain their septic systems.

Homeowners fail to see or simply ignore signs that their septic systems may be failing, do not pump their tanks often enought and do not comply with inspection and maintenance regulation for alternative systems. While the Virginia Department of Health (VDH) holds meetings and struggles for solutions, the EPA launched the annual SepticSmart Week, to encourage homeowners to get “SepticSmart.”

The United States has made tremendous advances in the past 35 years to clean up our rivers and streams under the Clean Water Act by controlling pollution from industry and sewage treatment plants. In order to continue to make progress in cleaning up our rivers and streams EPA has turned their focus to controlling pollution from diffuse, or nonpoint, sources. Things like stormwater runoff and septic systems. According to EPA, these nonpoint source pollution are the largest remaining source of water quality problems. However, these are the most difficult sources of pollution to address, because eliminating them involves changing the behavior of millions of people. Unfortunately, we did not do enough to control pollution from diffuse, or nonpoint, sources- from our homes and living.

Non-point source contamination has always been under the oversight of the states, and the nature of the sources of this contamination make it very challenging for even state and local regulatory agencies to make any progress. More people need to understand their responsibility to control their own sources of nonpoint source pollution starting with the most basic maintenance and care of their septic systems.

Simply pumping out your septic tank would be a good start at reducing nonpoint pollution. EPA and the Virginia Department of the Environment (through the VDH) have struggled with the challenges of better management of septic systems. It is assumed that in Virginia a fairly rural state that at least a quarter of households use a septic system to treat their wastewater. Proper septic system care and maintenance is vital to protecting public health and preserving valuable water resources that provide drinking water to our rural residences and communities and the environment, but has been difficult to achieve.

Taking the steps recommended by the EPA for SepticSmart Week would be a great start at reducing nonpoint pollution of our waters. Homeowners can do their part by following these SepticSmart tips:

1. Protect It and Inspect It: In general, homeowners should have their traditional septic system inspected every three years and their alternative system inspected annually by a licensed contractor and have their tank pumped when necessary, generally every three to five years.
2. Think at the Sink: Avoid pouring fats, grease, and solids down the drain, which can clog a system’s pipes and drainfield.
3. Don’t Overload the Commode: Ask guests to only to put things in the drain or toilet that belong there. For example, coffee grounds, dental floss, disposable diapers and wipes, feminine hygiene products, cigarette butts, and cat litter can all clog and potentially damage septic systems. Flushable wipes are not flushable and do not break down in a septic tank.
4. Don’t Strain Your Drain: Be water efficient and spread out water use. Fix plumbing leaks, install faucet aerators and water-efficient products, and spread out laundry and dishwasher loads throughout the day and week. Too much water at once can overload a system if it hasn’t been pumped recently.
5. Shield Your Field: Remind guests not to park or drive on a system’s drainfield, where the vehicle’s weight could damage buried pipes or disrupt underground flow.

Monday, September 19, 2016

Rain, Storms, Sea Level Rise and Flooding

Earlier this summer, extremely high moisture content in the air combined with a very slow-moving tropical depression resulted in what a blogger at the NOAA (National Oceanic and Atmospheric Administration) described as an inland tropical storm. Rain over a weekend totaled over 30 inches in some areas. Louisiana is very low and flat so the flooding was wide spread and long lasting. Septic systems and sewer systems were inundated. We heard about the flooding, but not about the sewage in the flood waters.

This was followed by hurricane Hermine, though barely a category 1 hurricane, it brought 10 days of rain and overloaded sewer systems in St. Petersburg and the Gulf Coast of Florida. Officials in St. Petersburg had to release between 100 and 200 million gallons of only partially treated sewage and rainwater to the environment to protect public health by keeping the sewer systems from backing up into homes.

Every four years the American Society of Civil Engineers, ASCE, grades the infrastructure in the United States, from water mains, sewer systems and plants, power lines connected to homes and businesses and the electrical grid spanning the U.S.; the neighborhood streets and the national highway system, dams, rail roads, airports. Infrastructure is the foundation of our economy, connecting businesses, communities, and people, making us a first world country, but the ASCE tells us that our infrastructure is in sad shape.

In their last report the grade for drinking water infrastructure was a D. In many parts of the nation, much of the piping that delivers water to our homes and businesses is almost a century old, nearing the end of its useful life. The lead contamination to the drinking water in Flint, Michigan is just an example of the havoc a failing water system can bring. Interruption in water supplies is another problem. The government reports that there are an estimated 240,000 water main breaks per year in the United States. Assuming every pipe would need to be replaced, the cost over the coming decades could reach more than $1 trillion, according to the American Water Works Association (AWWA), though new technology is being demonstrated to reduce that cost and extend the life of older piping systems. Nonetheless, our water distribution system needs to be replaced not just broken water mains repaired.

The ASCE grade for wastewater was also a D. The ASCE estimates that $298 billion will be required over the next 20 years to maintain and upgrade the nation’s wastewater and stormwater systems. As in the water delivery systems pipes represent the largest capital need, three quarters of the costs. Fixing and expanding the network of pipes will reduce sanitary sewer overflows, combined sewer overflows, and other pipe-related issues like urban sinkholes. In addition, our waste water treatment plants do not have the capacity and in system storage to handle the additional flows from large storms while maintaining public health. These systems need to be expanded and improved.

Before the floodwaters in Louisiana had receded, NOAA weighed in and developed an analysis using the best readily available observational data and high-resolution global climate model simulations. The analysis was conducted by scientists from NOAA’s Geophysical Fluid Dynamics Laboratory, Princeton University, the Royal Netherlands Meteorological institute, and Climate Central’s World Weather Attribution project. It was based on methods, observations, and models that have been widely used before, but this analysis has not yet been peer-reviewed.

NOAA scientists found that heavy downpours along the Gulf Coast have increased since the middle of the last century, and that is consistent with what climate experts have predicted would happen as greenhouse gases warmed the planet: more water vapor in the air to fuel extremely heavy rain. The scientists performing the analysis concluded that warming due to greenhouse gases has made events like the one in August at least 40% more likely and 10% more intense than they were 100 or so years ago.

NOAA stated that due to past climate change and sea level rise (some not due to climate change) we can expect more frequent massive storms and hurricanes in the future in this part of the country. In addition, at the end of August a report from Zillow warned that rising sea levels may inundate more than 2 million homes in the coming decades. Our coastal cities and towns need to be prepared for storms and flooding. These events should be planned for.

Our nation is growing poorer. Our government spends about $3.8 trillion dollars a year while taking in only $2.4 trillion in income tax revenues. You can see all the cash flows in the chart below and it is not a pretty picture. With failing infrastructure, rising sea levels and more frequent storms, rather than repair and restore after each storm event and delay addressing our infrastructure deficiencies, we need to plan for the future. We need to think about abandoning the most vulnerable areas to the seas.

There are over 105 models of the planet and its climate, though the scientist keep refining the models and improving them, there remain simplifications, assumptions and things about our plant and how it responds to change that are unknown. Ignoring all that, the Intergovernmental Panel on Climate Change (IPCC) estimates it is necessary to keep total planetary emissions below 1,000 gigatonnes of CO2 equivalents by 2100 to have a global warming of between 1.3 degree Celsius to 3.9 degrees Celsius. Unfortunately, it seems certain that we will bust through that budget in the next 20 years even if all the promises under the Paris accord are met.

Though I’m not a big fan of the accuracy of many of the climate models, I have no doubt that climate is changing and sea level is rising at least here in Virginia. We need to prepare for the future our nation is going to face. While we as a nation still have the financial flexibility to make changes, we need to plan the future of our nation.
Note that the US borrows $583 billion beyond borrowings from SS

Thursday, September 15, 2016

The Brain’s Waste Removal System

The brain consumes over a quarter of an ounce of protein and more than one fifth of the total energy used by the body each day. The protein is not completely consumed and wastes must somehow be eliminated from the brain. Until just a couple of years ago, scientists believed that some sort of degradation of wastes took place in brain cells. However, now based on the work or Steven Goldman and Maiken Nedergaar both of the University of Rochester building on the work of others we now know that the brain has its very own waste elimination system.

In most of the body a system of fluid-carrying vessels, the lymphatic system eliminates protein waste from tissues. Drs. Goldman and Nedergaar discovered that the perivascual space in the brain is a neural lymphatic system that provides a conduit for cerebrospinal fluid. The scientists called the intricate system of vessels that snakes throughout the brain the glymphatic system, the brains lymphatic system. The brains blood vessels are surrounded by perivascular spaces. These are sleeves that surround every blood vessel. The outer wall of these sleeves consist of extensions from a specialized cell called astrocyte. These astrocytes are support cells within the neural network. Now we know that the end feet of these cells complexly surrounds the arteries, veins, capillaries and spinal cord that clear and allows for the transport of fluid throughout the brain.

The scientists used a chemical dye to stain the cerebrospinal fluid and microscopic techniques enabled them to see deep inside a live brain. They found that pulsations in the brain arterial system from the heart pumping blood drives the cerebrospinal fluid through the perivascular space through the area between brain cells and finally to the perivascular space around the veins to clear the waste from the brain. Using astrocytes as conduits, the cerebrospinal fluid moved through the brain tissue where it picked up the discarded proteins such as beta-amyloid peptides which are associated with Alzheimer’s disease.

In Alzheimer’s disease aggregates of beta-amyloid form plaques between brain cells that is believed to contribute to the disease process. The scientists found that in a healthy brain beta-amyloid is cleared from the brain by the glymphatic system. These proteins and potentially others associated with neurodegenerative diseases could build up is the glymphatic system were to malfunction.

In a series of studies using mice that they trained to sit still under the microscope while awake the scientists were able to study and compare the flows of cerebrospinal fluid in the glymphatic system in awake and asleep mice. It seems the mice grew bored and fell asleep and the scientists were able to watch while tracer chemicals moved through the glymphatic system and compare awake and asleep in the same mice . It turns out that the cerebrospinal fluid falls dramatically in awake animals and rose by more than 60%-90% while the mice were asleep. The scientists were able to prove that sleep is essential to protein waste removal in the brain.

Much more research needs to be done, but the scientists working in this area are beginning to understand what triggers the increased removal of beta-amyloid peptides. We are still a very long way from effective treatments for Alzheimer’s, beta-amyloid plaque buildup, or synucleain protein buildup associated with other neurodegenerative diseases, but you can start by making sure you get plenty of sleep. Many Alzheimer’s patients experience sleep disturbances long before their dementia becomes apparent. The scientists have speculated that the sleep disturbances may not be a side effect of Alzheimer’s, but a contributing factor to the disease.

Monday, September 12, 2016

Goose Creek

Goose Creek Reservoir was created by building a 20 foot high dam on Goose Creek in 1961. The reservoir was designed to hold 325 million gallons of water, but that was soon reduced by the buildup of silt. As water demand continued to grow, it was necessary to expand the water storage by building a second dam and reservoir on the same creek to provide an emergency 120 day supply of water.

Beverdam Creek Reservoir was finished in 1972 and added over 1,340,000 million gallons of water storage. As the watershed for Beaverdam Creek Reservoir is small, pumps allow it to pump water from Goose Creek to fill the reservoir. The reservoir was not designed to refill during times of drought, but to be the backup water supply when Goose Creek River flow got too low.

In January 2014, Loudoun Water acquired all the water infrastructure located in Loudoun County from the City of Fairfax, including Beaverdam Creek Dam and Goose Creek Dam. As the new reservoir owner, Loudoun Water assumed the responsibility to maintain and repair the dams to protect public safety, meet operational objectives and meet ecological needs for water. How Goose Creek is being used to meet water supply demands in Loudoun County has come into question. Until last year the Beaverdam Reservoir had always released water during dry periods in August and September and during droughts to maintain the flow in Goose Creek. However, according to the Loundoun Soil and Water Conservation District on September 9th of last year and again on September 27th Goose Creek ran dry during the day.
from LSWCD
When the City of Fairfax owned Beaverdam Creek Dam and Goose Creek Dam they pumped water out of the reservoir over a 24-hour shift at a relatively low rate. When Loudoun Water took over the operation of the dams they switched from a 24 hour pumping to a 12 hour pumping cycle. This shorter pumping cycle required a higher pumping rate and while Loudoun never allowed Goose Creek to go dry over a 24-hour period; on the 12-hour cycle, they were pumping more water than was freely flowing last September and the Creek ran dry during the pumping.

Various stakeholders held a series of meetings with Loudoun Water this past spring. What came out of the meetings is that Loudoun Water believed that they can cut off flow of Goose Creek, and are not responsible to supplement creek flow when it falls naturally. In meetings with the Conservation District Loudoun Water stated that the flow through Goose Creek is not Loudoun Water’s mission, rather their mission is water supply. Goose Creek is a state waterway and is regulated by Virginia’s Department of Environmental Quality (DEQ), and though DEQ requires a permit if average daily withdrawal of water exceed 10,000 gallons a day in any month, the regulation does not apply to them. The Beverdam Creek Dam and Goose Creek Dam reservoir operations were grandfathered under the regulations.

Loudoun Water is a state chartered Utility Company. It is a political subdivision of the commonwealth and not a department of Loudoun County. Loudoun Water is governed by a nine-member board who serve four-year terms and are appointed by the county’s Board of Supervisors. The company is funded by its customers water bills and it is required to spend money only its mission or delivering clean, safe water to its customers 24/7 and building and maintaining the infrastructure to do that. Loudoun Water was once primarily a wholesale customer of Fairfax Water, as the county has grown Loudoun Water has expanded rapidly to supplying 50 million gallons of water a day to customers, and faced new challenges.

Though, last spring Loudoun Water stated that the reason they switched to a 12-hour shift last summer was because staff needed to use a disinfectant in the water and that a 12-hour shift was necessary to keep the disinfectant active. This summer Loudoun Water switched back to operating the Goose Creek water plant 24 hours a day, which should allow them to operate at a lower pumping level during this month, the time when groundwater levels (which naturally supplement the creek are lowest). In addition, Loudoun Water plans to augment the flow in Goose Creek with water from Beaverdam Reservoir to keep Goose Creek flowing.

This appeares to be a significant change from Loudoun Water’s operating plans from last spring as reported by the Loudoun Conservation District. However, it may be that Loudoun Water has realized that if they were not withdrawing water from Goose Creek for water supply, the flow would always be adequate. Maintaining the natural resources including the river ecology of their essential resources is an essential portion of their mission. It appears that the operating philosophy of the Interstate Commission on the Potomac River Basin (ICPRB) has been incorporated into Loudoun Water’s management of Goose Creek.

The ICPRB manages the withdrawals of water from the Potomac River for all the utilities in the region while still maintaining a minimum flow in the river for sustaining aquatic resources. ICPRB allocates and manages water resources of the river through the management of the jointly owned Jennings Randolph Reservoir (built in 1981), Potomac River Low Flow Allocation Agreement (1978) and the Water Supply Coordination Agreement in 1982 which designated a section of the ICPRB as responsible for allocating water resources during times of low flow. These steps improved reliability of the water supply and ensured maintenance of in-stream flows to meet minimum aquatic habitat requirements.

Segments of Goose Creek are the subject of a plan to reduce bacterial contamination, and a government working group has been meeting to develop management measures to address the contamination. Loudoun Water has been working on the plan with the ICPRB, DEQ, Loudoun and Fauquier counties, the Soil and Water Conservation District, and other groups. In addition, Loudoun Water is currently engaged in building a new raw water intake in the Potomac River and a new raw water pumping station adjacent to the Leesburg Water Filtration Plant. These are scheduled to be operational in 2017. To help them meet future water demands though times of drought Loudoun Water will be able to store more than 8 billion gallons of water in quarries that are being acquired and converted to reservoirs.

Thursday, September 8, 2016

Don’t Use Coal Tar Based Sealcoat on Your Driveway

Sealcoat used in the central, southern, and eastern U.S. commonly contains coal-tar pitch. Polycyclic aromatic hydrocarbons (PAHs) escape from coal tar based sealcoat and other pavement materials when they are scraped, washed or blown by wind carried into stormwater and snow runoff. There is a concern that these chemicals may enter the nation’s water supply and through dust be ingested by children. At least seven of the two hundred PAHs are known to cause mutagenic/carcinogenic behavior in human cells. A recent study by scientists at Baylor University and the U.S. Geological Survey (USGS) found that living adjacent to a coal tar sealed driveways, roadways or playgrounds is associated with a significant increase in lifetime cancer risk. In addition, previous studies have found that PAHs carried by stormwater build up in the sediments of rivers streams and lakes and impact our water resources.

Coal-tar-based sealcoat usually contain 20-35% coal-tar pitch and contains from 50,000 to 100,000 milligrams per kilogram (or parts per million) PAHs which is about 1,000 times higher than PAH concentrations in asphalt-based sealcoat products used in the western states, and hundreds of times higher than PAH concentrations that appear in tire particles, used motor oil, or other urban sources.

Friction from car and truck tires grinds pavement sealcoat into small particles, which are incorporated into the dust on the pavement surface. Testing has shown that dust on coal-tar-sealed pavement contains PAHs at concentrations that are hundreds of times higher than those in dust on concrete or unsealed asphalt pavement. Not only is the transported dust carried by wind and stormwater to our waterways, but it is also carried on our clothes and shoes into our homes where it becomes part of the household dust.

Incidental ingestion is a pathway to exposure to many chemicals, especially for children. The USGS/ Baylor study focused on incidental ingestion of the seven cancer-causing PAHs. The scientists only looked at the concentration of the seven PAHs that have quantitative evidence of probable carcinogenic impact. They found that the average estimated lifetime dose for someone living adjacent to coal-tar-sealcoated driveway or road was 38 times greater than for someone living adjacent to unsealed asphalt pavement. About more than half of the exposure occurs before the age of six. The estimated lifetime cancer risk for someone who spends just the first 6 years of their life living adjacent to coal-tar-sealed pavement is about 25 times higher than urban background exposure.

In addition, in sediment studies in the eastern half of the U.S., the USGS found that of PAHs in stormwater ponds, and streams traceable to coal tar sealcoats ranging from 21% to 54%. While there are other active sources of PAH contamination such as wood fires, tires and vehicle emissions, coal tar sealcoat is one of the more easily preventable sources. In addition, safer substitutes are now available which are comparable in performance and price. Most highway departments have not used coal tar products on asphalt pavement for many years; and use is banned in part or all of 19 states, though not Virginia. You should avoid sealing your driveway with coal tar based sealcoats to protect our water resources and our children. Use instead asphalt-based sealcoat emulsions with the asphalt concentration (the binder) to be 25-30%. There are also no-PAH options including acrylic-based and agricultural oil-based sealcoats, and cement-based micro-layers; however, durability can be an issue with these products and they are not as readily available.

Monday, September 5, 2016

Zika Spraying Kills Bees

Recently, on August 26, 2016, the Dorchester County Department of Health and Environmental Control reported four confirmed cases of the Zika Virus in the Summerville area of Dorchester County, South Carolina. In order to combat the spread of mosquito borne Zika viruses the county decided to use aerial spraying to supplement their ground based mosquito spraying trucks and larvae control programs. Dorchester County sprayed a pesticide called Naled, a neurotoxin which kills adult mosquitoes and other insects. The aerial spraying killed millions of bees.

Prior to the aerial spraying on Sunday, August 28, from 6:30 AM to 8:30 AM, Dorchester County sent a notices on Friday, August 26 at 9:15 AM and sent a second notice on Saturday, August 27 at 8:48 PM to various media outlets and contacting registered beekeepers before beginning the operations. Unfortunately, not all beekeepers in the area were informed, they managed to overlook Flowertown Bee Farm and Supply in the town of Summerville. The spraying wiped out 2.3 million bees that were housed in 46 hives at their commercial bee operation.

Spraying Naled from the air has been previously used to cover areas that cannot be reached by truck. In a single year in Florida, more than 6 million acres were sprayed from the air with the chemical, according to a new brief from the Centers for Disease Control and Prevention (CDC), “Aerial treatment of areas with products that rapidly reduce both young and adult mosquitoes can help to limit the number of mosquitoes that carry the Zika virus. Repeated aerial applications of insecticide has reduced mosquito populations as a part of an integrated vector management program.” The agency even urged that the technique should be used to curb Zika in Puerto Rico.

Since the Dorchester County spraying killed honeybees, it probably also killed wild bees and other pollinators, Honeybee deaths are just easier to notice, because wild bees are mostly solitary. There are no pesticides that kill adult mosquitoes – known as adulticides – that are safe for bees. Even pyrethrin, which is produced from chrysanthemums, is known to be toxic to bees. A safer route would be to use larvicides, which kill mosquito larvae and are safer for bees.

Honey bees are already under stress. Colony Collapse Disorder (CCD) is threating both wild and managed pollinator populations in the United States and the rest of the world. Pollination is essential for fertilization and for plants to produce seeds and fruit. Without pollination there would be no fruits, no vegetable and no seeds. Though, grasses, conifers, and many deciduous trees are wind-pollinated, most flowering plants that we eat need birds and insects for pollination. CCD has wiped out millions upon millions of honeybees over the past two decades.

Thursday, September 1, 2016

DC Water Start Construction of Water Tank

Last week for the first time in 71 years DC Water has begun construction on a water storage tower. This tower is the last piece of the plan to equalize water pressure east of the Anacostia River and part of a larger program to equalize water pressure and maintain the water system throughout the District of Colombia.

Washington DC had fallen woefully behind in the maintenance and upgrade of its water distribution system. The EPA’s Safe Drinking Water Act regulations effectively only regulate the water treatment plant which in the cast of Washington DC is operated, maintained and upgraded as needed by the Army Corp of Engineers. DC Water is responsible for the water distribution system which is very old and not well maintained.

One of the long term problems has been poor water pressure, impaired water quality, system reliability, and ensuring adequate flows throughout the southern section of the existing Anacostia 1st high service area, DC Water planned years ago to improve pressure with a new pumping station, water tower and replacing the transmission mains. The pumping station was built in 2008, but the tower was delayed by the permitting and approval process.
The old water tower in 2009 from DC Water

The height of the water tower provides the pressure. One way that a water tower improves water pressure is by being tall. For every foot of height, water pressure increases 0.43 pounds per square inch (psi). A typical municipal water supply runs at between 50 and 100 psi. The height and size makes the water tower very visible and the impact on the views and the historical St. Elizabeth’s campus. The water tower needed to be located on the highest natural point adjacent to the current piping system feeds. The base of the tower is approximately 90 feet diameter and the top is 60 feet in diameter. Much of the delay can be attributed to the necessary process of impact studies and public hearings.
Consultants floated balloons to study impact of the new tower
The new St. Elizabeth’s water tower will be 170 feet tall and have an effective overflow elevation of 310 feet above sea level. This should increase water pressure by 22 psi for customers in the lower Anacostia area according to DC Water. The tank will have a volume of 2 million gallons in order to provide sufficient water storage during emergencies and to meet daily demand and cost $14,000,000 including all the costs associated with the site evaluations, hearings, public meetings and construction.