Thursday, September 27, 2012

The CO2 Tipping Point Not Yet Reached- Oceans and Vegetation Absorb More Carbon

The International Energy Agency, IEA, estimates that world CO2 emissions from fossil fuel combustion rose by 1 billion metric tons in 2011, a 3.2 % increase over 2010 to reach 31.6 billion metric tons (34.83 billion tons). In 2011 the top four world generators of CO2 emission from fossil fuels were in descending order China, the United States, the European Union and India who edged out Russia to take the number four slot. China contributed almost three quarters of the global increase, with its emissions rising by 720 million metric tons, or 9.3% to 8.46 billion metric tons of CO2, primarily due to higher coal consumption to produce electricity. Increases in the CO2 emission from fossil fuel combustion in 2012 is likely to be less since electricity use in China is up only 1% this year.

Nonetheless, the world CO2 emissions continue to increase. IEA not only collects data it also makes progress reports, and makes recommendations for implementing carbon dioxide controls worldwide to preventing the world from reaching the “Tipping Point” where global temperatures cannot be held within 2°C above pre-industrial levels. Initially, the climate science establishment thought the Tipping Point would be reached when world CO2 emissions from burning fossil fuel reached 32.6 billion metric tons of CO2 annually and global CO2 concentrations reached 450 parts per million. The “Tipping Point” was the 450 Scenario which limits global warming to 2 degrees by limiting concentration of greenhouse gases in the atmosphere to around 450 parts per million of CO2. We are currently very close to the 32.6 billion metric tons (just 1 billion metric tons above 2011 levels and the amount the world emissions increased last year.) However, though the atmospheric concentrations of CO2 continue to rise, the National Oceanic & Atmospheric Administration, NOAA, reports that CO2 concentrations have risen just 2.33 parts per million to 392.41 parts per million from August 2011 to August 2012.

Despite sharp increases in carbon dioxide emissions from burning fuel the level of carbon dioxide in the atmosphere has not increased as quickly. There appears to be a buffer provided by Earth’s vegetation and oceanswhich continue to soak up about half of the carbon dioxide emissions each year (though of course impact on marine ecology should be of concern) according to arecently published study led by the University of Colorado at Boulder. The study, led by Dr. Ashley Ballantyne, looked at global CO2 emissions reports from the past 50 years and compared them with rising levels of CO2 in Earth’s atmosphere during that time. The results showed that while CO2 emissions had quadrupled, natural carbon “sinks” that sequester the greenhouse gas doubled their uptake of CO2 in the past 50 years, potentially lessening the warming impacts on Earth’s climate.

The study showed global CO2 uptake by Earth’s sinks essentially doubled from 1960 to 2010, although increased variations from year-to-year and decade-to-decade suggests some instability in the global carbon cycle. According to the study, CO2 uptake by Earth’s land and oceans decreased in the 1990s (when most of the climate models were developed), followed by increased CO2 sequestering by the planet from 2000 to 2010. “Seeing such variation from decade to decade tells us that we need to observe Earth’s carbon cycle for significantly longer periods in order to help us understand what is occurring,” said Dr. Ballantyne. Marine Biologists are deeply concerned about the impact of increasing uptake of CO2 by the world’s oceans. Dissolved CO2 in the ocean forms carbonic acid making the oceans more acidic and damaging coral, the fundamental structure of coral reef ecosystems that harbor 25% of the world’s fish species.Take a look at the article in Nature (if you want to spend the money).

Monday, September 24, 2012

Using Up the Ogallala- The Groundwater Footprint of the U.S.

The High Plains aquifer commonly known as the Ogallala aquifer (because the Ogallala formation makes up about three quarters of the aquifer) became news and burst into public awareness due to the protests associated with the Keystone XL Pipeline. The Keystone XL Pipeline has been very controversial. Most of the environmental controversy has focused on the porous soils of the Sandhills and fears of a possible oil leak into the Ogallala aquifer which is one of the nation's most important agricultural aquifers. Moving the pipeline away from the aquifer or piping the Canadian oil through British Columbia should mitigate concern for contamination to the Ogallala, but oil leaks are a minor problem. Really, the oil does not move quickly or spread easily through the sedimentary deposits of the High Plains aquifer. There is a much bigger threat to the Ogallala; the aquifer is being depleted because the groundwater within it is predominately non-renewable. This groundwater aquifer that spans and estimated 174,000 square miles is the primary source of water for the High Plains. This was open range land until the groundwater from the aquifer was used to turn the range land into irrigated crops. However, according to John Opie in “Ogallala: Water for a Dry Land” this is essentially fossil water that was generated 10,000-25,000 years ago by the melting of the glaciers of the Rockies.
Water level declines in the High Plains Aquifer since 1958 

The High Plains aquifer is the most intensively used aquifer in the United States and 97% of the water is used for irrigation. Groundwater withdrawals from the High Plains aquifer represent about 20% of all groundwater withdrawals within the United States and have turned the dry range land in the center of the country into the breadbasket of the world. There are only about 2.5 million people living within the High Plains aquifer. With the grains we grow and export we are exporting our water reserves and possibly the future of the region. The High Plains aquifer is being depleted (and contaminated) by irrigation. In the central and southern High Plains water levels have fallen from 50 to more than 150 feet primarily in parts of Kansas, Oklahoma, New Mexico and Texas.  

In  the past year Drs. Tom Gleeson, Yoshihide Wada, Marc F.P. Bierkens and Lodovicus P.H. van Beek each a distinguished voice in groundwater research have pulled together to try to popularize the concept of Groundwater Footprint in order to focus attention on the sustainability of groundwater use. While I think the “global groundwater footprint” is not particularly useful beyond seeing how important groundwater use is globally, their groundwater footprint concept may end up being a very powerful tool. Water is regional and while the authors of “Water Balance of Global Aquifers Revealed by Groundwater Footprint” point out that some groundwater consumption can be transferred to an adjacent aquifer (they use the Upper and Lower Ganges aquifers in India as their example) more often water use and recharge are a dictated by local conditions. An excess of water along the Amazon basin is not particularly useful to Saudi Arabia. However, the authors measurement of “groundwater footprint” is really a measure of groundwater sustainability. A groundwater footprint is a simplified tool to see the water balance between recharge and use of an aquifer and could be used to include groundwater sustainability in developing water, economic and agriculture policies using the virtual water and water footprint analysis. If the water use is not sustainable, then ultimately we are not sustainable.

Groundwater footprint, as the authors point out, could be used with the satellite-based Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) to quantify groundwater depletion. Researchers at the University of California, Irvine, the University of Texas, and the Hydrological Sciences Branch at NASA GSFC have worked in partnership to apply GRACE and GLDAS to real world groundwater monitoring. As these tools develop, the groundwater footprint could end up being an intuitive management tool. The authors found that 80% of the world’s aquifers are not being depleted, but that of the 20% that are being depleted are being depleted at such a vast rate that the global average footprint is of unsustainable groundwater use. In the United States the High Plains and the Central Valley aquifers are being depleted. We as a nation need to examine our agricultural policies and incentives, even our energy policies (corn for ethanol is squandering 40% of the corn crop and the non-renewable water in it to dilute gasoline) and the way we value and price water to ensure that we will have food in the future. 

Thursday, September 20, 2012

The Costs and Savings from Energy Efficiency Projects for the Home

Last Monday in the Wall Street Journal was an article “The Economics of Installing Solar Power.” They had a lovely chart with costs and returns that had virtually nothing resembling the actual costs and savings of my solar photovoltaic system. Though the costs of solar panels have gone down considerably since I purchased my system, and I discovered that solar panel installation costs less in San Francisco than Virginia and I assume cost less in urban centers than in rural areas. Nonetheless, the chart in the Wall Street Journal made me feel terrible, the cost of the fictional solar systems in the Wall Street Journal were all $5,500 a Kilowatt (KWh). Nonetheless, payback period is entirely dependent on the cost of electricity, rebates and incentives. Depending on how I continue to play the incentive game, my payback period could potentially fall in line with the fictional systems in the Wall Street Journal.

Right now (and for the past few years) electricity costs me $0.115 a Kilowatt. No matter how you look at it solar power costs more than the eleven and a half cents a kilowatt that NOVEC (Northern Virginia Electric Cooperative) is charging for residential power. The payback without tax credits and rebates would exceed the life of the system regardless of how good or bad a deal I got. In addition, my solar photovoltaic system cost way more on a per Kilowatt basis than the system cost they used. Prices have really come down on solar panels, but I do wonder if their costs include permits, plans and engineering, as well as the costs to change the electric panels and repair and seal the walls. The Wall Street Journal priced solar at $5,500 per KWh. The 5 KWh systems in the Journal have a listed cost of $27,500 while my installed cost was $58,540 for 7.36 KWh DC. Sizing their system up to my system size proportionally would be a cost of $40,480, but my cost included $1,500 for permits, plans and engineering. Nonetheless, you could probably install the same system today (even on the edge of nowhere) for $15,000- $18,000 less so even without the state of Virginia rebate the first year cost would be the less than my cost. 

My lifetime to date energy production

The actual cost of a solar photovoltaic system is really based on rebates, tax incentives and utility subsidies. Virginia no longer has rebates available and does not have any utility subsidies or solar renewable energy requirement, but I managed to snag a rebate when they were available and register my system in Washington DC before their market rules changed. My system was grandfathered when the market was closed. The Solar Renewable Energy Credits or SRECs are worth about $290 each right now (though I have sold them for between $95 and $350). Each SREC is a credit for each megawatt of electricity that is produced and used by me. SRECs have value only because some states have Renewable Portfolio Standards, RPS, which require that a portion of energy produced by a utility be produced by renewable solar power. Utilities in some states can fulfill that requirement by buying SRECs from solar installation owners and utilities in Washington DC are buying mine. As long as the market is not oversupplied (as is Pennsylvania) and there is a financial penalty for not meeting the solar carve out, then I can make more money selling SRECs than I save on the power I produce. With any luck I will be able to sell enough SRECs to get my payback period into the 10-15 year range. Energy savings from solar power are the most expensive no matter how you look at it.

A significantly shorter payback was from upgrading my heat exchanger. This past July I replaced my air heat pump with a new efficient system, replaced the ducting system in my attic and installed an attic fan and gable vent. The result is improved comfort and a $77 a month reduction in my electric bill during the summer cooling season and I assume an equivalent reduction in the winter bill. However, there are generally 3-4 months a year that I do not run the heating or cooling system so my annual savings will be closer to $600-$700 a year. That is about half the savings from my solar panels at fraction of the cost and I get a cooler, more comfortable home.

Though I had always assumed that when the time came I would replace my heat pump with a geothermal heat pump, that’s not what I ended up doing. After considerable research and getting several estimates I replaced my air heat pump with another air heat pump, a more efficient one, and re-ducting the attic to create a more efficient and effective system. The costs of installing a geothermal system in my existing home far exceeded the benefits. Based on the estimates I received the cost to reconfigure my finished basement ($5,000-$10,000) and install either a vertical coil or standing column well ($12,000-$18,000) on top of the cost of the heat pump and upgraded ducting combined with technical difficulties (a daylight basement and fractured rock system with no overburden), and the potential I might impact the drinking water aquifer or damage my garden ended my plans to retrofit a geothermal unit into my existing home. Instead I installed a more efficient and powerful heat pump, redesigned the ducts in my attic, and installed an attic fan. The result was heaven- a master bedroom that could hold 71 degrees at the heat of the day on a 100 degree day and the bedroom over the garage that in the past always was 10 degrees hotter than the master bedroom in summer and 10 degrees colder in winter was within 1 degree of the master bedroom and my electric bill fell by more than $77 for the month of July. (The decrease was about the same year to year or June to July.)

First of all my air heat pump like most is a split heat-pump systems consisting of two parts: an indoor (blower) unit and an outdoor (condensing) unit. Both units are designed to work together. Air Heat-pump systems manufactured today, by law, must have a seasonal energy efficiency ratio (SEER) of 13 or higher. Seasonal Energy Efficiency Rating (SEER) or Heating Seasonal Performance Factor (HSPF) for heat pump systems are the efficiency ratings on heat pumps, the higher the SEER/HSPF, the more efficient the equipment. The SEER is measured in average Btu output over the season divided by the watt hours and is the standard measure of energy use efficiency. Generally, the higher the SEER/HSPF of a unit, the higher the initial cost and lower the operating cost.

My old heat pump was a 3.5 ton with a SEER of 12 and a HSPF less than 8. Once the temperature reached 90 degrees in Virginia the heat pump ran continuously and could not keep the master bedroom or the bedroom over the garage cool. The master bedroom struggled to stay below 78 degrees and the bedroom over the garage was always 10 degrees warmer despite additional insulation. The old system was only 8 years old when the coil failed, but replacing the coil ($2,500) seemed like throwing good money after bad. We decided to do it right. After getting several bids and weighing my options, I had Randy Hayes and his boys (Hayes Heating and Air Conditioning) install a 4 ton Carrier Infinity 19 seer heat pump model #25HNB948, its matched multiple speed air handler and a programmable thermostat. The high efficiency two-stage heat pump allows me to oversize the unit slightly so that it can handle the hottest days without sacrificing optimal performance on more temperate days so the old rule that if a system is oversized, the system will cycle on and off too frequently, greatly reducing its ability to control humidity and its efficiency is no longer strictly true. I rounded up from base line Manual J to get the 4 ton.

In addition we (Randy and his boys) removed the old sagging flexible ducts and installed two new galvanized steel trunk lines (one to each side of the house) with 3 inch reflective duct wrap and tied the new flex lines into the existing vent boots with as little sag as possible (thanks to Randy’s middle son) using silver flexible ducts insulated with R-8. We minimized the amount of flexible ducting in the attic using as much galvanized ducting as was feasible (at an additional cost of $3,000, but the galvanized portion of the ducting will last longer and in all real world tests gives better air flow). Flexible ducts consist of three layers an inner core of a metal helix encased in a foil film, an insulation layer and the outer vapor barrier jacket. While fully extended properly installed flexible duct can be as good at maintaining air pressure as a galvanized steel duct, performance deteriorates as the ducts sag.

In the real world there is some degree of sag even in good installations and it tends to increase over time. In poor installations (like mine was) there were sharp bends and excess lengths snaked all over the attic in a daisy chain of connection using fiberglass plenums. This caused the inner layer of the flexible duct to crumple (it is a soft spring) and the helix pop out. Instead of smooth circular tube the flexible duct turned into a bumpy pathway for the air that caused turbulent flow and very significant pressure drop from the beginning to the end of the duct. In my case, there was almost no air flow in the bedroom over the garage (the room furthest from the air blower). The reason the drop was so great is that the ducts operate at very low pressure and small resistance due to friction can have a very big impact on flow. The old ducts were also R-6 insulation and black collecting more heat. Now I have conditioned air flowing into the bedroom over the garage and you can feel the cool air come out of the duct.

Finally to help the whole system work well, we added another gable vent (on the south facing gable) and a temperature controlled attic fan in the east gable. The result was that fabulous feeling of luxury (during the test period) of lying in bed in the middle of the day on a 100 degree Sunday and pulling the covers up because it’s cold. After a week of freezing out the bedroom at all times of the day and night, we settled back at a more reasonable temperature, but still reduced our energy use by about 670 KWh for the month. Total cost $16,300 for everything-heat pump, ducting, attic fan, installation, removal of the old equipment and cleanup. Part of the cost was simply to have heating and air conditioning, part for improved comfort and the rest for energy savings.

So, I did not get a geothermal heat pump, but I am more than satisfied with the cost savings and comfort improvement of my new air heat pump over the old one. The geology of my property was not ideally suited for a horizontal coil, too many rocks. The water table is shallow (under a hundred feet). My septic field and 56 new trees were in the way of the drill rig needed for a vertical loop or standing column well, and the location of my ducting and blower were not easily accessible to a new well without digging up the driveway, patios and/or garage or moving all the utilities in the house. For another house geothermal could be an easier or better solution. I had not thought through the requirements of geothermal when I purchased the house and finished the entire basement.

Finally, the first energy project I did and you should too, was to seal and insulate the house. Heating and cooling account for 50% to 70% of the energy used in the average American home. Inadequate insulation and air leakage through ducts, walls and roofs are the major sources of wasted energy in most homes (see upgrading my ducting above). Though, my house was built in 2004 the insulation and thermal properties were not optimal. I turned to the Building Envelop Research of the Oak Ridge National Laboratory for guidance. The Oak Ridge National Laboratory performs their Building Envelop Research for the US Department of Energy, DOE, and publishes their guidance in their “Insulation Fact Sheet,” which is available on the blog home page and through this link. Insulation and sealing was the most cost effective project I had done. Despite having it professionally done the payback was under 4 years in straight energy savings.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

Monday, September 17, 2012

Recycled Water in Fairfax, Virginia

All the water that ever was or will be on earth is here right now. More than 97% of the Earth’s water is within the in oceans. The remaining 2.8% is the water within the land masses, as groundwater, rivers, streams, lakes, and within the ice caps and glaciers (over 77% of fresh water is currently frozen). Only a fraction of water falls as rain each year to make the rivers flow, recharge lakes and groundwater. The water on earth never rests, it is constantly moving within the hydrologic cycle along various complex pathways and over a wide variety of time scales. Water moves quickly through some pathways -rain falling in summer may return to the atmosphere in a matter of hours or days by evaporation. Water may travel through other pathways for years, decades, centuries, or more. As the demand for water grows in our population centers, we are straining to meet the demand. Even in generally water rich areas there are limits to the availability of water and United States has slowly and quietly begun to address the availability of water by recycling the water.

Direct water recycling is reusing treated wastewater for beneficial purposes such as agricultural and landscape irrigation, industrial processes, toilet flushing, and replenishing a ground water basin (referred to as ground water recharge) and less commonly returning the water directly to reservoirs. Since 1978, the upper Occoquan Sewage Authority has been discharging recycled water into a stream above Occoquan Reservoir, one of the two potable water supply sources for Fairfax County, Virginia. Recycled water has been part of the Occoquan supply for 34 years and chances are if you are in Fairfax, parts of Prince William and Loudoun counties you have been regularly drinking recycled water. Noman M. Cole, Jr., a very forward thinking engineer, developed the Occoquan Watershed Policy in 1971. This policy was the acknowledgment that to continue supplying the region with drinking water, the Occoquan Reservoir would be used both for wastewater disposal and public water supply. To do this and protect public health the Occoquan Watershed Policy not only specified the type of waste treatment practices that would have to be adopted on a basin-wide scale, but it provided for an on-going program of water quality monitoring to measure the success (or failure) of the waste water treatment. This resulted in the construction of the Upper Occoquan Service Authority, UOSA, advanced wastewater treatment plant with tertiary treatment to replace the eleven small secondary treatment plants.

Wastewater treatment within the basin would have three stages of treatment, primary, secondary and tertiary or advanced treatment.  Primary Treatment consists of sedimentation and screening of large debris using screens and large settling tanks. Until 1960’s primary treatment was the only form of sewage treatment in most places. Secondary treatments usually include biological and/or chemical treatment. One of the most common biological treatments is the activated sludge process; in which primary wastewater is mixed with bacteria that break down organic matter and cleans the water. Oxygen is pumped into the mixture. A clarifying tank allows sludge to settle to the bottom and then the treated wastewater moves on for tertiary treatment. Coagulation, filtration and disinfection take place in tertiary treatment. A coagulant is added, UOSA uses the high-lime process to reduce phosphorus to below 0.10 mg/L. This process also serves as a barrier to viruses, captures organics leaving secondary treatment, and precipitates heavy metals and other suspended particles. The UOSA permit requires total suspended solids, TSS, below 1 mg/L and chemical oxygen demand, COD, below 10 mg/L. To meet these stringent levels, multimedia filtration and activated carbon are used. Filtration removes organic matter, microorganisms and mineral compounds, and excess nutrients. The final barrier to pathogens is a chlorination and dechlorination process. UOSA uses sodium hypochlorite and sodium bisulfite. UOSA is has an expansion program underway to expand capacity to 54 million gallons a day, but according to 2012 Fairfax County disclosures, the plant currently operates closer to an average of just over 13 million gallons a day.

After disinfection the reclaimed water is released to the watershed cleaner than the rest of the river, according to Dr. Tom Gizzard ofthe Occoquan Watershed Laboratory. Financed by the wastewater treatment plants and Fairfax Water, the Occoquan Watershed Laboratory (OWL), was established by the Virginia Polytechnic Institute Department of Civil Engineering. The laboratory began its Fairfax operations in 1972, and has conducted comprehensive studies of receiving water quality, and effects of the waste water treatment effluents for 40 years. The current Director of the Laboratory is Dr. Tom Grizzard, professor of Civil Engineering at Virginia Polytechnic Institute and State University (Virginia Tech). When I spoke to Dr. Grizzard he pointed out that the water released into the Occoquan is “highly reclaimed wastewater” and not sewage effluent. There is a difference and Dr. Grizzard and the OWL staff make sure of it.

The Occoquan Watershed Policy is the oldest and largest reservoir augmentation program in the county and the second largest water recycling program in the country. The largest water recycling or reclamation program in the country and in the world belongs to the Orange County Water District and the Orange County Sanitation District jointly owned and developed the Groundwater Replenishment (GWR) system, the world’s largest water purification plant for groundwater recharge. The GWR System diverts secondary treated sewer water and purifies it through a series of tertiary treatments: microfiltration, reverse osmosis, ultraviolet disinfection and hydrogen peroxide. The cleaned water is returned to the groundwater basin to increase both the water supply and quality rather than discharging the treated sewer water to the ocean. The additional treatment of the wastewater is much cheaper that desalinization and makes the groundwater use sustainable-utilizing the groundwater basin as a reservoir.

In Fairfax County Virginia, water is withdrawn from the Potomac River and the Occoquan Reservoir and filtered, cleaned, disinfected and delivered as drinking water to the homes and businesses throughout the county (and in parts of Prince William and Loudoun Counties). Waste water from toilets, sinks, drains is collected by the sewer systems and six waste watertreatment plants that serve some portion of Fairfax County.  On average, Fairfax County uses 160 million gallons of drinking water per day from both the Corbalis plant and the Griffith plant drinking water plants. The combined total capacity of both plants is 345 million gallons/day. The drinking water systems are sized to deliver the peak demand on a 100 degree day when everyone is doing laundry and watering their lawns and everything else we do with water on hot summer days.  Most of that water (except what is used to irrigate landscaping) finds its way to a waste water treatment plant within the region. The wastewater processed in Fairfax County is fully treated and released into the river and streams of the Potomac watershed. (We will ignore the issues currently being addressed at Blue Plains.) To ensure the continuation of water supply during droughts, Fairfax is party to a low flow allocation agreement with the members of the Interstate Commission on the Potomac River Basin, ICPRB. In addition, Fairfax bought the rights to 14 billion gallons of water from the Jennings Randolph Reservoir. On an ongoing basis ICPRB coordinates Fairfax Water’s low flow water withdrawals between the Potomac and Occoquan. The Occoquan Reservoir contains 11 billion gallons that receives both natural river flow and about 13 million gallons of reclaimed water daily.
From Fairfax County

Noman M. Cole, Jr. Pollution Control Plant (named in honor of the engineer) is now engaged in a direct water recycling program, reusing treated wastewater for landscape irrigation and industrial processes. The Noman Cole plant releases its reclaimed water to Pohick Creek. Now the plant is engaged in the Water Reuse Project also known as the Purple Pipe Project, to directly reuse some of the water. (The pipes are colored purple to designate the water as non-potable.) The Purple Pipe project has completed the first phase of the project and is delivering 1.4-1.6 million gallons of fully treated waste water to the Covanta Fairfax, Inc. Resource Recovery Plant and Laurel Hill Golf Course via a recently constructed 5 mile purple pipeline, two large pumps, instrumentation and hypochloride disinfection. The Laurel Hill Golf Course will use the water to augment the on-site irrigation lake during the summer. Due to recent rains, the demand for water by the golf club is limited, but according to Michael McGrath the Director, Wastewater Treatment Division, Department of Public Works and Environmental Services, for Fairfax County, the Laurel Hills Golf Club can draw up to 27 million gallons a year of reclaimed water from the Noman Cole Plant. The Covanta Resource Recovery Plant is allowed to use up to 560 million gallons a year of Purple Pipe Water to irrigate the adjacent athletic fields and other purposes. The Noman Cole plant discharges and average of 45 million gallons a day to Pohick Creek, so this is just a small fraction of the daily flow.  The reclaimed water from Noman Cole makes up a significant flow to Pohick Creek so that there is a minimum environmental flow that should continue, but there is opportunity for growth in the Purple Pipe Project.

The project, which began in 2009, cost $16 million for the first phase (or about $600 per foot) with $6.5 million in funding coming from the federal stimulus funds through the American Recovery and Reinvestment Act, and the remainder was paid for by Fairfax county through a loan from the Virginia Department of Environmental Quality Clean Water Revolving Fund Loan Program. In the first partial year of operation the project will produce about 20,000 credits for Noman Cole Plant in the Virginia Nutrient Trading Program in addition to the reduced cost water. Nutrient trading programs provide wastewater treatment plants with flexible options for meeting and maintaining permitted nutrient load limits, but also could be used to meet the approximately 25% reduction in nutrients required under the federally mandated Chesapeake Bay TMDL. A nutrient credit is a reduction of one pound of nitrogen and worth (at the current time) $2. Though the first phase of the Purple Pipe Project will generate more credits next year, still at $2 per credit plus the price received for water and costs or $600 per foot there is virtually no way for Fairfax to utilize Purple Pipe to meet the TMDL goals or increase water supply without a significant rate increases for water and large volume users. If using reclaimed water is necessary for the region to maintain its quality of life, the cost of water will have to rise to cover the costs because we are already using all the cheap water.

The numbers break down like this: this project would have to produce cash flow of about $918,000 per year (rather than the projected under $200,000 for water and nutrient credits) to pay for the $16,000,000 cost at 3% interest (current AAA interest for 20 year bonds is above 3%) over 25 years.  (Though for this project the $6.5 million from the federal stimulus funds does not have to be repaid.) The Purple Pipe project is a very cool project, but at the current cost of water the capital costs are prohibitive. Or maybe, we've just had a glimpse of the marginal cost of water.

Thursday, September 13, 2012

The Doctor and His Septic System

I was waiting in a doctor’s exam room when he arrived with friendly banter about a sport I had no knowledge of due to lack of interest. I laughed and said he should try a topic I was interested in or knew something about. Kidding, I suggested we talk about groundwater or septic systems. He immediately launched into the horrifying story of how he operates his septic system and his concerns about its operation. He apparently had lived in his house for 15 years and never once pumped his septic tank. Instead he had two drain fields which he switched between every six months and dutifully poured septic system additives down the drain every month. He had been using some “granules” but now was pouring a “blue liquid” and was worried about the new liquid. He had no idea of the basics about septic system operation and maintenance, and no idea about what he had probably done to his system. The good news is that neither he, nor his neighbors are using the groundwater and he has adequate money to fix his system. So, this is for a certain wonderful doctor who shall remain nameless. (By the way, dear doctor, you can build a fabulous new alternative septic system for less than the cost of a new mid-range luxury sedan. That is the upper end of what fixing your problems will cost.)
Failing septic system from NCDH presentation

A typical septic system has four main components: a pipe from the home, a septic tank, a leach or drain field (alternative systems might have drip fields, sand mounds or peat tanks where a leach field is not possible or has failed), and the soil. The septic tank is a buried, watertight container typically made of concrete, fiberglass, or polyethylene. It holds the wastewater long enough to allow solids to settle out (forming sludge) and oil and grease to float to the surface (as scum). The septic tank also allows partial decomposition (by natural bacterial action) of the solid fecal matter. Compartments and a T-shaped outlet in the septic tank are intended to prevent the sludge and scum from leaving the tank and traveling into the leach field area. Some newer systems have screens and filters to keep solids from entering the leach field, but older systems typically do not. These filters and screens can become clogged and need to be cleaned out regularly to prevent septic sludge from backing up into the house.

Septic tank wastewater flows (by gravity or pump) to the leach field, where it percolates into the soil, which provides final treatment by natural soil filtration which removes harmful bacteria, viruses, and nutrients. Suitable soil is necessary for successful wastewater treatment. Microbes in the soil can digest or remove most human produced biological contaminants from wastewater before it eventually reaches groundwater. There are also Alternative systems (or AOSS) that have additional treatment tanks or components like peat moss tanks or sand filters to assist in the filtration process. For a septic system to work properly, the waste stream cannot contain too much solid material or scum. High quantities of solids in the waste stream will overwhelm the leach field. Initially, nitrogen and fecal bacteria will be released to the groundwater as the soil becomes saturated with solids and scum. Eventually the perforations in the pipes to the leach field through which waste water flows can become clogged and the waste may ultimately backup through the system into your home or surface in the yard.

To keep a septic system operating optimally, a septic tank must be pumped every few years to remove the scum and solid layers. Steady use of water throughout the day and water conservation should be practiced because too large a flow of waste water and the solids in the tank will be stirred up and not settle and be carried out to the drain field. Also, the drain field does not have an unlimited capacity. The more water your family uses, the greater the likelihood of problems with the septic system. Finally, you need to limit what goes down the drain to prevent bacterial die-off in the tank so that it will continue to function as designed. Die-off of the bacterial necessary for a septic system to perform properly has been seen in experiments where excessive amount of harsh household chemicals were added to the septic tank. As little as of 1.85 gallons of liquid bleach, 5.0 gallons of liquid Lysol cleaner, or 11.3 grams of Drano drain cleaner added to a 1,000-gallon septic tank have caused die-off of the bacteria in experiments. Other factors that can cause die-off include the excessive use of anti-bacterial agents, and, in certain cases, antibiotic medications taken by members of a household.

However, in normal use, you do not need to add a chemical or biological stimulator or an enhancer to a septic tank that is designed, operated, and maintained properly. The naturally occurring bacteria are already present within human fecal matter are adequate for the system to function properly. Contrary to popular belief, chemical additives, such as caustic hydroxides and sulfuric acid, should never be added to a septic system. Adding these chemicals will destroy the bacterial population in the septic tank, change the permeability characteristics of the soil absorption system, and may cause groundwater contamination.

Often, manufacturers of biological additives market their use to restore the bacterial balance in a septic tank on a monthly basis as part of a routine maintenance program. As mentioned above this is not necessary because these bacteria are already present in human feces. These kinds of additives are thought to be harmless to the functioning of a system. A lack of need has not stopped manufacturers from advertising their products. However, some studies indicate that enzymatic products might have the ability to reduce the amount of oil and grease in the septic tank, but the oil and grease flows out of the tank to the soil. The scum layer in a septic tank “holds” fats, grease, and floatables, preventing their escape to the drain field. Enzymatic products can “break up” this scum layer and increase its mobility, allowing it to enter the soil absorption system. So you save on pumping your septic tank and instead slowly destroy the functioning of your drain field.

Manufacturers’ claims that septic additives either eliminate the need for pumping of a septic tank or can restore permeability of the soil absorption system are entirely unsubstantiated according to Cornell University. No product has been demonstrated to allow a homeowner to escape regular septic tank pumping and maintenance, but can contribute to the premature failing of a soil absorption system. The drain field has a limited lifetime and capacity. After a few years, the solids that accumulate in the septic tank should be pumped out and disposed of at an approved location. If not removed, these solids will eventually overflow, accumulate in the drain field, and clog the pores in the soil and the openings in the pipes. While some clogging of soil pores occurs slowly even in a properly functioning system, excess solids from a poorly maintained tank or a tank where enzyme additives were used instead of pumping the tank can completely close all soil pores so that no wastewater can flow into the soil. The sewage effluent will then either back up into the house, flow across the ground surface over the drain field, or find another area of release in the septic system. If this happens, you may need to construct a new drain field on a different part of your lot or install an alternative treatment system like peat tanks or sand filters. Pumping the septic tank after the soil drain field has become completely clogged will not rejuvenate the system only alleviate the surfacing of waste water until the tank fills up again. I am intrigued by the idea that the Doctor’s alternating drain fields every six months might have slowed the clogging of the drain field by allowing it to rest for half of each year. Usually, a second leach field is installed when the primary field is failing and used this way when the second leach field developed problems also. 
From NC Department of Health presentation

In some cases where the drain field has become clogged and no longer can adequately absorb the wastewater, the toilets and sinks might not drain freely. A black residue may remain at the bottom of the toilet.  If the drain field can absorb the effluent, but no longer treat it, the sewage may contaminate the groundwater or surface water with fecal coliform bacteria and it could take a long time to identify that problem unless you and your neighbors are using the groundwater as a drinking water supply and test your water. Contaminated groundwater often looks and tastes just fine. If your drain field has become clogged, but is not backing up into your home there are several other signs: The ground near the drain field or other section of the septic system maybe wet or mushy, even during dry weather. The visible liquid in these wet areas is often dark (sometimes nearly black).The area around the failure may have a distinctive odor and flies are often attracted to the failure (especially in the hotter season). The lawn may grow greener in these areas. The grass is a brighter green over a failing drain field, distribution valve or other failed component.

While I know my doctor would never try to disguise a failing septic system in selling his home, not all people are as honorable. Before buying a home with a septic system, have it inspected by a licensed individual or Professional Engineer specializing in septic systems and knowledgeable about local geology and soils. If the property is also on well water thoroughly test the water quality, also. Though commercially available dyes and tracers can be used to confirm a suspected problem, they will not identify all septic system failures, due to the type of failure (releasing untreated waste water into the subsurface) or due to intentional masking of the problem. If you pump a septic tank it will take several days or more than a week (depending on the size of the tank and household) for water to be released to the drain field again. That is generally more than enough time for the wet areas of the yard to dry out and will keep the tracer dyes from being seen in the yard.

Commercially available dyes and tracers are best used to establish the flow path of wastewater and confirm a suspected problem. Dyes and tracers are most efficiently used to confirm cross-contamination of wells by nearby septic systems. They can be used to identify which of nearby septic systems is the source of a well contamination problem much less expensively than a DNA test on the waste bacteria (oh yeah, with enough money you can do that, too).  Tracking of sewage effluent in groundwater and surface water systems is complex and difficult to predict using dyes and tracers. Just because the dye or tracer does not appear does not mean that untreated sewage is not contaminating surface and groundwater systems or that a septic system is working properly.

Monday, September 10, 2012

The Water Footprint of Humanity

I have seen the statement that 90% of water used globally is used for agriculture, more and more frequently. This “new” statistic has replaced the often quoted World Health Organization statement that 80% of freshwater used is for irrigation. The WHO number is based on measurement of water withdrawals from rivers and groundwater for irrigation. The 90% number (it is actually 92%) is from a recent paper by Arjen Y. Hoekstra and Mesfin M. Mekonnen of the University of Twente in the Netherlands titled “The Water Footprint of Humanity.” They estimated the consumptive use of rainwater for agricultural production and add that amount of water to groundwater pumping and surface water diversion to examine the consumptive use of water for agriculture.  Thus, the 90% of water used globally refers to an estimate of how much irrigation water and rainfall water is consumed  by crops and agriculture in general.

The Water Footprint has no relationship to the rainwater available and does not relate in any way to the sustainability of surface and groundwater use patterns. In all countries the amount of water in agricultural products accounts for the largest proportion of water used. According to their methods agriculture accounts for 92% of the water footprint, industry 4.4% and domestic use (the water we drink and bath with) accounts for 3.6%.  I’m not at all sure that utilization of rainwater in watering crops a meaningful measurement of water use. It leaves unaddressed sustainability of water use, the importance of (or lack of importance of) the rainfall on woodlands, recharging of groundwater that is not being depleted, stormwater runoff and other rainwater uses. It almost implies an ownership of rainwater that falls in various lands. The purpose of the work was to develop a global water management tool, but does not address the complicated aspects of water that is at times renewable and other times not.

In an attempt to look at water beyond the watershed these two Dutch scientists in a series of studies have attempted to trace the concept they called the Water Footprint, by including data on rainwater use and volumes of water used for human and animal waste assimilation to track waters movement in water-intensive commodities as they move across the globe. By importing food, a country externalizes their water footprint.  The scientists identified the water content of various foods by estimates based on global precipitation, temperature, crop, and irrigation maps and the yield, production, consumption, trade and wastewater treatment statistics for nations. There are assumptions underlying this data on planting and harvesting dates per crop per region, feed composition per animal and country as well. In addition the scientists assumed that industrial water supply are spread according to population densities.

Arjen Y. Hoekstra and Mesfin M. Mekonnen then estimated the water content of all products and determined a trade balance with water content in a product as the measure. Using their methodology the major gross virtual water exporters are the United States, China, India, Brazil, Argentina, Canada, Australia, Indonesia, France and Germany. The scientists note that “all these countries are partially under water stress, which raises the question whether the …choice to consume the limited national (surface and groundwater) resources for export is sustainable and most efficient.” Good question. These scientists were trying to develop a way to look at the global dimension of freshwater resources to try to understand and ultimately solve the most pressing and urgent water problems, addressing the limits on the supply of and contamination of fresh water on the planet, and the ability of the planet to feed themselves. However, their operating framework ignores comparative advantage (French wine) and seems to suggest that water in agricultural products is not properly valued. However, they cannot actually determine what the country limit to agricultural production is because they have not addressed the limits of water supply, and unsustainable use of water.

Let’s look at this from another angle.  All the water on earth is over 4 billion years old. “It's one of the more astonishing things about water — all the water on Earth was … here when Earth was formed, or shortly thereafter…in the first 100 million years or so. There is, in fact, no mechanism on Earth for creating or destroying large quantities of water.” The quote above is from Charles Fishman’s book, The Big Thirst: The Secret Life and Turbulent Future of Water. All the water that ever was or will be on earth is here right now. More than 97% of the Earth’s water is within the in oceans. The remaining 2.8% is the water within the land masses. The land masses contain all the fresh water on the planet. Of the land surface water, 77% is contained in icecaps and glaciers and for all practical purposes is inaccessible in the short run, and on a warmer planet will not be stored in ice. The remaining fresh water is stored primarily in the subsurface as ground water with a tiny fraction of a percent of water is stored as rivers and lakes which are renewed by rainfall.

Only a fraction of water falls as rain each year to make the rivers flow, recharge lakes and groundwater. The water on earth never rests, it is constantly moving within the hydrologic cycle along various complex pathways and over a wide variety of time scales. Water moves quickly through some pathways -rain falling in summer may return to the atmosphere in a matter of hours or days by evaporation. Water may travel through other pathways for years, decades, centuries, or more—the groundwater stored in the Wasia aquifer in Saudi Arabia fell from the atmosphere as rain thousands of years ago. In the Middle East, in California, in India and throughout the planet we are using groundwater faster than it is being recharged. We are using up our stored water reserves to grow food and the water reserves are shrinking. So, that determining the water footprint in the way that Arjen Hoekstra and Mesfin Mekonnen have attempted does not convey the limited time that mankind can continue to use water in the way that we are using water now.  

As of 2010, 783 million people worldwide still relied on unimproved water sources (surface water from lakes, rivers, dams, or unprotected dug wells or springs) for their drinking, cooking, bathing and other domestic activities. In 2004 (the last year for which statistics were available), water, sanitation and hygiene was responsible for 1.9 million annual deaths from diarrhea. Most diarrhea deaths in the world (88%) are caused by unsafe water contaminated by human or animal waste, sanitation or hygiene. In addition, there are estimated to be as many as one billion hungry people in the world, some even in the United States.

The earth has a fixed amount of land and water. Water is complicated by the variability in weather and the variable length of different parts of the water cycle. Precipitation does not fall in the same amounts throughout the world, in a country, or even a region and varies from year to year. We are on a trajectory towards a world where ever increasing numbers of people will not have food security and will starve during drought years.  Farmers in the United States feed 20% of the world’s population on just 10% of the earth’s surface that is how we ended up the largest virtual water exporter. The U.S. agricultural sector is the most successful in the world, but will not be able to meet the world’s projected food demand and we may not want to mine groundwater in California to export Almonds. California might want to drink some of that water. Even if all the world’s farmers adopted conservation-based agricultural production techniques (emphasizing soil health) there are limits to what the earth can reliably produce each year. During a “good” period of temperature and rainfall in the most agriculturally productive areas and the most marginal areas the world’s population and demand for food will grow to exceed the average production and the next drought or the exhaustion of a groundwater aquifer will bring catastrophic consequences. It has always been the nature of man (see the Mayan Empire).

According to the Dutch scientists, over a fifth of the nations are net water importers, they have an external water footprint. Many highly water scarce countries (that can afford it)  are externally water dependent- Kuwait, Jordan, United Arab Emirates, Israel, Yemen, Malta, and Cyprus. Though, not all countries with a large external water footprint are water scarce. One of the interesting observations was that the Netherlands and United Kingdom are net importers of food and thus water.   Arjen Y. Hoekstra and Mesfin M. Mekonnen state “For governments in water-scarce countries such as in North Africa and the Middle East, it is crucial to recognize the dependency on external water resources and to develop foreign and trade policies…” to ensure a sustainable and secure import of water intensive commodities (food). It is not viable to irrigate crops with desalinated water.  According to the US Geological Survey it takes 20 gallons of water (on average) to grow one apple, 4,000 gallons of water to grow one bushel of corn, 11,000 gallons of water to grow one bushel of wheat, 15,000 gallons of water to raise a cow. The Dutch scientists finish by pointing out that China with  a relatively internal water footprint is leasing lands in Africa to secure their food supply and water resources outside their country.

Thursday, September 6, 2012

Maintaining 24/7 Water in America

From the American Water Works Association 2011

In most of our communities and cities we inherited the water infrastructure which was built by previous generations. This water storage, treatment, and distribution system delivers as much water as we want whenever we want it (under most circumstances). This amazing infrastructure to deliver 24/7 water was built beginning in the late 19th century and throughout much of the 20th century. We have barely thought twice about our water and have taken for granted the capital investment made by those previous generations. The water bill that most pay barely covers the cost of delivering the water and some repairs.  No infrastructure lasts forever and we have failed to properly maintain and plan for the orderly replacement of the water distribution systems. In the United States we have never experienced the need for pipe replacement on a large scale and have taken for granted what we were given. However, in our cities water mains are failing at an ever increasing rate.

The water distribution systems in most of our big cities have reached the end of their useful life. As documented by the U.S.Environmental Protection Agency Drinking Water Needs Survey and Assessment 2007  and the American Water Works Association, AWWA, report: “Buried No Longer:Confronting America ’s Water Infrastructure Challenge” a large proportion of US water infrastructure is approaching, or has already reached, the end of its useful life. The need to replace or rebuild the pipe networks that deliver water comes on top of other water investment needs, such as the need to replace water treatment plants, upgrade treatment technology to respond to emerging contaminants in our raw water supplies, replace storage tanks and on-going monitoring and compliance costs. The investment needs for our wastewater and stormwater systems will also have to be addressed for those systems are old as well.

According to the AWWA, restoring existing water systems as they reach the end of their useful lives and expanding them to serve a growing population will cost at least $1 trillion over the next 25 years in 2010 dollars, if we plan to maintain 24 hours per day on demand of water service for our country. The AWWA analysis includes investments that will be necessary to meet projected population growth, regional population shifts, and service area growth over that period. The EPA estimates that the twenty-year capital improvement needs for infrastructure investments necessary from 2007, through 2026, for the existing water systems to continue to provide safe drinking water to the public to be $335 billion assuming no growth in service area and no population shift. EPA’s “Clean Water and Drinking Water Infrastructure Gap Analysis,” actually estimated drinking water systems’ 20-year capital needs in the range of $204 billion to $590 billion with a point estimate of $335 billion, the always cited cost. The EPA costs exclude maintenance and replacement of dams and reservoirs because they are excluded from the EPA’s Drinking Water State Revolving Fund, DWSRF, funding. The smallest systems actually have the highest cost per person for pipe replacement because the residences are more spread out- there are more feet of pipe main per residence and the EPA’s data may be weakest in that category.

The EPA estimate for total national need of $335 billion in 2007 is comparable to the 2003 estimate of $331 billion (as adjusted to 2007 dollars). Indicating that no progress has been made in the long term replacement and during the period 2003-2007 only repairs seem to have been made.  Both the 2003 and 2007 EPA Assessments and the AWWA assessment clearly point to the nation’s water systems having entered a “rehabilitation and replacement era in which much of water utilities’ existing infrastructure has reached or is approaching the end of its useful life.” It is to be noted that no real progress has been made in water infrastructure replacement since 2007.

We are living with aging drinking water infrastructure, with increasing incidence of unplanned failures. We can continue to respond to water emergencies or, we can carefully prioritize and undertake drinking water infrastructure renewal investments to ensure that our water utilities can continue to reliably and cost-effectively support the public health, safety, and economic vitality of our communities. The choice is ours and will be made community by community. According to the EPA, water utilities in the United States is highly fragmented with approximately 52,000 water systems with 56% of that number serving populations of 500 or less. The large number of relatively small systems may not have the expertise to analyze a system and develop a replacement plan and may not have the financial capability to raise capital independently. However, smaller systems can more easily vote for capital surcharges and may be eligible under the DWSRF. The Safe Drinking Water Act, as amended in 1996, established the DWSRF to make funds available to drinking water systems to finance infrastructure improvements. The program emphasizes providing funds to small and disadvantaged communities and to programs that encourage pollution prevention as a tool for ensuring safe drinking water.

How will all this money be spent?  Transmission and distribution pipes, pumps and valves represent about 60% of the projected cost of replacement and rehabilitation. Although the least visible component of a water system, the buried pipes of a transmission and distribution network generally represent most of a system’s capital value. Even small rural systems may have several hundred miles of pipe. In larger cities, replacement or rehabilitation of even small segments of the extensive underground networks of water supply pipes can be very costly, due not only to the cost of construction but also the costs related to disruption to the city’s traffic and business. Replacement projects for water mains, valves and pumps present such challenges that they are typically only undertaken after failure driven by a utility’s need to continue providing potable water to its customers while preventing contamination of the water prior to delivery.

The rate at which water mains fail varies greatly by type of pipe, age of the pipe, water characteristics, soil characteristics, weather conditions, and construction methods. Some pipe materials have been found to degrade prematurely; galvanized pipe has turned out to be particularly susceptible to corrosion in certain soils, and unlined cast iron pipe is susceptible to internal corrosion. Asbestos cement pipe presents challenges to protect workers during pipe repairs. Currently, many water systems are using ductile iron or polyvinyl chloride pipe (PVC) for construction and replacement now. It remains to be seen how long this infrastructure will last.

The EPA estimates that 22% of the costs of water infrastructure rehabilitation will have to be spent on treatment and compliance.  Treatment facilities vary across systems depending on the quality of their source water and type of contamination present. Treatment systems can range from a simple chlorination for disinfection to a complete conventional treatment system with coagulation and flocculation, sedimentation, filtration, disinfection, laboratory facilities with computer automated monitoring and control devices. This also includes projects to remove contaminants that affect the taste, odor, and color of drinking water, but are otherwise harmless (or almost so). These costs may increase due to deterioration of source water quality.

Source water infrastructure is estimated at about 6%. This includes constructing or rehabilitating surface water intake pumps and pipes, drilled wells, and spring collectors. Drinking water comes from either ground water or surface water sources. Wells deliver groundwater. Rivers, lakes, and wells in karst terrain under the direct influence of surface water are considered surface water sources. A high-quality water supply can minimize the possibility of microbial or chemical contamination and may not require extensive treatment facilities. Many of the source water needs involve construction of new surface water intake structures or drilling new wells to obtain higher quality raw water to minimize the treatment costs.

The remaining 12% of water infrastructure needs are attributed to storage and miscellaneous other projects. Storage includes projects to construct, rehabilitate, or cover water storage tanks, but it excludes dams and raw water reservoirs because they are specifically excluded from DWSRF funding. A water utility cannot function without sufficient storage to provide adequate supplies of treated water to the public, particularly during periods of peak demand. This storage allows the systems to maintain the minimum positive pressure required throughout the distribution system to prevent the intrusion of contaminants into the (deteriorating) distribution networks which are not “water tight.”

Monday, September 3, 2012

Update on Endocrine Disruption in Water Supplies

From USGS paper cited below

Earlier this month Vicki Blazer of the U.S. Geological Survey published a new paper, “Indicators of Reproductive Edocrine Distruption in Fish in the Chesapeake Bay Watershed.” Dr. Vicki Blazer is a mairine biologist and researcher at the U.S. Geological Survey, USGS. Dr. Blazer received the American Fisheries Society 2010 Publications Award for her article investigating the mortality of fish in the Potomac River basin and is a fish biologist at the West Virginia Science Center studying the impact of contaminants of emerging concern in rivers and streams of the lifecycle and health of fish on the Chesapeake Bay and its tributaries. This paper is a summary of the most recent research (previously published) by the USGS and others on endocrine disruption in fish in the Chesapeake Bay watershed and the implications to our lives.

The Chesapeake Bay watershed feed the Chesapeake Bay, the largest and most productive estuary in the United States. It serves as a nursery ground for the fish and shellfish industry and protects the coast from storm surges and filters pollution. The estuary filters water that is carrying nutrients and contaminants from the surrounding watershed. The nutrients in proper balance bring fertility, but excess nutrient contamination to the Chesapeake Bay has caused degradation in the habitat and impact to fish and other animals. As a result, US EPA has taken control of the situation and has developed a new federally mandated TMDL (total maximum daily load) to try to restore the natural balance in the estuary by controlling nutrients in the local waters. The TMDL addresses pollution from phosphorus, nitrogen and sediment and allocates a pollution budget among the states which will decrease over time. However, according to Dr. Blazer, the fish (and other aquatic organisms) in the Chesapeake Bay watershed are being exposed to a complex mixture of chemicals that may have additive, synergistic or antagonistic effects.

In the Potomac River watershed, largemouth bass show signs of feminization (testicular oocytes and vitellogenin in males) but appear to be less sensitive than smallmouth bass to the effects of estrogenic compounds. The scientists discovered that the smallmouth bass have both a higher incidence of intersex (male fish with eggs) occurrence and a high incidence of skin lesions and large fish kills in the Potomac and James Rivers. Smallmouth bass may be the most sensitive indicator of environmental health in the Chesapeake Bay watershed. The smallmouth bass is a warning that should not be ignored, but the pollution problem they represent are beyond our understanding at this time. More work needs to be done.

Although feminization of male fish has most commonly been associated with exposure to human wastewater-treatment-plant effluent, the prevalence of male smallmouth bass with intersex characteristics is not consistently higher downstream from these point sources than upstream in the areas of the Potomac River watershed that were studied. It is not simply the residue of birth control pills in human waste. However, some additional biomarkers, such as the ratio of gonad weight to body weight and plasma vitellogenin concentrations in female bass, do appear to be adversely affected by the presence of wastewater-treatment plants upstream from the study site, but more is going on.

The sources of the endocrine-disrupting chemicals associated with intersex smallmouth bass appears to be BOTH effluent from wastewater-treatment plants and runoff from agricultural land, animal feeding operations, and urban/suburban land. All impacts of mankind. Other factors, including wastewater-treatment-plant effluent flow, number of animal feeding operations, and number of poultry houses were also associated with an increased intersex severity. Within the Potomac River basin the data showed that the higher the human population density the higher the incidence of intersex in the smallmouth bass. Also, the higher the percentage of agricultural land use density the higher incidence of intersex in smallmouth bass. The data appears to suggest beyond a certain density of agricultural land and/ or human population, the smallmouth bass population is impacted.

The USGS plans to work with the Chesapeake Bay Program to identify the chemicals that are causing the intersex, skin lesions and fish kills. The Chesapeake Bay Program intends to develop toxic contaminant reduction strategies to be added to the Chesapeake Bay TMDL by 2015. The impact on human life and the ecosystem of these and other emerging contaminants is not known, but now is the time to find out the impact from the substance we’ve been allowing to enter the waters of the earth. We need to determine the impact and fate of these micro pollutants before we implement the watershed cleanup plans to make sure we are implementing the right strategies for the health of the entire ecosystem which may include eliminating the use of certain chemicals and other actions.