Nitrates in the Conodoguinet Creek

Created By: Megan Alley, Brian Altman, Shaun Lawson, Randy Pajovich, and Kevin Riley

Conodoguinet Creek

Conodoguinet comes from an Indian word meaning "A long way with many bends". The creek was rightly named this for its twisting and bending path. The Conodoguinet Creek is approximately 90 miles long and flows east into the Susquehanna River. The creek drains an area of 470 sq miles that is occupied by both agricultural and developed land.

Map of Conodoguinet Creek

There are 33 permitted point source discharges into the Conodoguinet Creek. Water tested from wells in Cumberland county and in the Carlisle area near the Condoguinet Creek have nitrate concentrations that are among the highest in the nation, frequently exceeding 10 mg/L, and USGS surveys have identified the Conodoguinet Creek as having one of the highest delivery yields of nitrogen to its mouth--the Susquehanna river, and therefore to the Chesapeake Bay, which suffers heavily from excessive nutrient runoff of chemicals such as nitrogen and phosphorus.

Water Pollution

Water pollution is the contamination of water bodies such as lakes, rivers, oceans, and groundwater caused by human activities, which can be harmful to living things that live in or use the water. Contamination of water by humans, especially surface water, is often by sewage effluent, fertilizer runoff, and industrial chemical discharge. The EPA separates water pollution sources into two categories: Point Source and Non-Point Source pollutants. Point Source: water pollution are from locations such as sewage treatment plants, factories, and ships. Non-Point Source: water pollution primarily comes from agricultural run-off, mining sites, and paved roads. Both the Conodoguinet Creek and the waters it is a tributory to, the Susquehanna River and the Chesapeake Bay, have been suffering drastically from oversedimentation and excessive nutrient runoff from places such as sewage plants and farms that overfertilize watersheds, causing huge spikes in certain species of plant life at the cost of dozens of others. One of the key nutrients at the heart of this problem is nitrates.

Nitrates

What are nitrates?:

Nitrates are Nitrogen-Oxygen chemical units. The primary sources of organic nitrates come from human sewage and livestock manure. The primary inorganic sources of nitrates are potassium nitrate and ammonium nitrate both of which are widely used as fertilizers. Nitrate compounds are very soluble in water and mobile in the environment. Nitrates migrate to ground water which is often used as utility or drinking water. They do not evaporate naturally in water. The only way nitrates can be removed from water is if they are consumed by living organisms or treated at a water treatment center. Human activities have increased environmental nitrate concentrations, with agriculture being the major source.

Nitrate Ion

Health Effects of Nitrates

Short-term and Long-term exposure can cause serious health effects to humans and the environment. Standards and regulations have been set by the Environmental Protection Agency (EPA).

Human Health Effects

Short-term Exposure

Excessive levels of nitrate in drinking water, even over a short period of time, has caused serious illness and sometimes even death in both adults and infants. The most common serious illness in infants is due to the conversion of nitrate to nitrite once the chemical has entered the body. This interferes with the oxygen-carrying capacity of human blood and as the nitrite connects with the red-blood cells it slowly depletes the amount of oxygen able to enter the body which causes suffocation. This condition is known as methemoglobinemia. Symptoms include shortness of breath and blueness of the skin. In infants this condition is called "Blue Baby Syndrome". Primarily for this reason it is recommended that baby formula be prepared with water of less than 50 mg/L nitrate and baby food focus on low-nitrate foods such as peas and brussels sprouts (about 1 ppm nitrate each) and avoid high-nitrate foods such as carrots, potatoes (23 ppm each), and spinach (121 ppm).

Long-term Exposure

Once again nitrates are most harmful after entering the body because of their conversion to nitrites. Long term exposure can cause serious illness and has lead to death. Conditions include diuresis, increased starchy deposits, and hemorrhaging of the spleen.

Nitrate Derivatives as possible Carcinogens

Nitrates and their common ionic complement nitrate are thought to be carcinogenic, however the ability for nitrite to combine with secondary amides, amines, and carbamates into suspected carcinogens, most notably N-nitroso compounds, has been noted in several non-human mammals. N-nitroso compounds were found to be carcinogens able to cross the placental barrier in several animal tests, regardless of the method of exposure to N-nitrosos. However, human epidemiological studies have yielded mixed results; studies of high-nitrate water supplies in Denmark and Colombia found positive correlation between nitrate concentration and stomach cancer, while the U.K. and other nations showed no correlation between nitrates and cancer incidence. Currently nitrate is not regulated as a carcinogen by the U.S. E.P.A., but it is under review for further research.

Environmental Health Effects

High nitrate levels in water often lead to eutrophication which in turn leads to excessive plant growth, usually in the form of algae. High plant growth is the cause for low oxygen levels in water, this often leads to decreased populations in biodiversity. It can also lead to the death of aquatic creatures such as fish. Nitrates do not evaporate therefore they remain in the water until consumed by plants or other organisms. Nitrates from the Conodoguinet flow into the Susquehanna River which flow into the Chesapeake Bay. Because of increased nitrate levels phytoplankton growth increases resulting in insufficient sunlight for seagrasses to grow. When the phytoplankton die they sink to the bottom where they are decomposed by aerobic bacteria which deplete the oxygen levels at the bottom of bay.

Algal Bloom

Nutrient Loading

Nutrient Loading is when the nutrient cycle is effected by outside additional artificial nutrients, mainly created by humans. These nutrients are mainly nitrates and come from fertilizers and usually end up in "aquatic systems". The abundance of nutrients results in excessive growth of algae which disrupts the underwater ecosystem.

Algal Blooms

Occur when there is an abundance of algae in a underwater ecosystem. The overgrowth of algae is usually caused by eutrophication which is when chemicals such as nitrates and phosphorus are added into an ecosystem from an unnatural source such as fertilizer runoff. The algae that is a result of an excess of nitrates and phosphorus is usually blue-green algae, which is actually a bacteria. The algae feed on plants which they are aiding in killing, and their population greatly increases. The algae population often becomes so large that it can be seen on the waters surface. The bacteria become so great in number that they use the majority, if not all of the oxygen in a specified area creating dead zones in which no organisms can survive.

Point Source Pollution

Point Source pollution is any source that is responsible for the discharge of pollutants. The Conodoguinet Creek has been largely affected by point source pollution. The point sources of pollution that are contaminating the Conodoguinet Creek the worst are sewage treatment plants, factories, livestock facilities and transportation corridors. Pennsylvania requires that point source pollutions obtain permits before they are allowed to discharge any waste. There are thirty-three permitted point source pollutants on the Conodoguinet creek.

Point Source vs. Non-Point Source Pollution

Waste Loads

There are six sewage treatment plants located on the Conodoguinet Creek that are continuously releasing treated sewage into the Creek. In the past this did not raise any problems however recently there has been a population increase in the surrounding area of the Conodoguinet Creek. The population has increased by 20,000 in the past ten years and is continuing to increase. This is a problem because with more people comes more waste and larger waste loads causing more work for the sewage plants; for example, the Carlisle water plant located just outside the borough was originally constructed in 1949, and expanded in 1965 to a capacity of processing 6 million gallons per day. From 1993 to 1995, Carlisle paid $7.5 million to expand the plant's capacity to 9 million gallons per day, though Carlisle is only permitted to withdraw 7 million gallons per day from the Conodoguinet Creek.

These treatment plants are not all equipped with up to date materials to efficiently sort through larger amounts of wastes, allowing more nutrients to seep through the treatment process and release into the Conodoguinet Creek. Along with the increase in population, warehouses and industries are continuing to be built. Most factories and warehouses transport their waste to sewage treatment plants, therefore with the continuance of building comes an increase in large waste loads. These large waste loads are causing an increase in the number of nitrates released into the Conodoguinet Creek.

Transportation Corridors

There are numerous transportation corridors that surround the Conodoguinet Creek because of the high level of traffic in the surrounding area. The major highways and roads such as route 81, 581, and 114 cross over the creak at certain points. Transportation corridors are of high protection priority because of the possibility of spills into the Conodoguinet Creek. These transportation corridors can result in large chemical spills that leak into the creek. It is of high priority because of the high traffic of tractor-trailers and cars in the surrounding area. There are also railroads, which are of high priority because of the possibility of a spill. Railroad cars especially tankers provide the chance of a spill or leak which release chemicals into the creek causing an increase in nitrates and other nutrients.

Effects

Point source pollutions located on the Conodoguinet Creek are creating an abundance of nitrates and other nutrients in the Creek. The pollution has a larger impact on the lower areas of the creek because the pollution flows down river and gathers. This is where the most nutrients can be found. The abundance of nutrients that is coming from point source pollutants causes various problems for the Creek such as the death of fish and unhealthy drinking water. If this problem continues bigger problems will arise and cause more trouble for the surrounding area of the Conodoguinet Creek.

Non-Point Source Pollution

Non-point source pollution is caused by the runoff of rain or melting snow, which collects pollutants as they move through the ground and migrate into a water source. There are many types of pollutants that the runoff picks up as it moves through the ground. There are many sources for non-point source pollutants. These main sources include, agricultural practices, urban runoff, energy production, sediment from improperly managed construction sites, stream banks, and crop and forest lands, salt from irrigation practices, bacteria and nutrients form livestock, pet waste, and malfunctioning septic systems.

Non-Point Source Pollution

-Agricultural Practices: Approximately 60% of the watershed is agricultural, almost 200,000 acres of cropland, pasture, and hayfield, most of which underutilize Best Management Practices. As such, both the Carlisle Borough and the Susquehanna River Basin Commission have noted agriculture as the single most significant contributor to nitrate pollution in the Conodoguinet area, followed generally by urban runoff. Non-point source pollution (which include nitrate pollution) in agriculture includes: pesticides,herbicides,fertilizer, erosion, animal feeding operations, irrigation, and nutrient runoff. All of these issues have been listed and implemented under the National Management Measures to Control Non-Point Pollution from Agriculture. Approximately 60% of the land immediately surrounding the Conodoguinet Creek is pasture, row crop, or hayfield, all of which are strong non-point contributors due to insufficient use of Best Management Practices and education. Stronger buffers of riparian zones to help collect some of the pollutants would help reduce the amount of pollutants entering the Conodoguinet, acting as natural filters.

Agricultural Pollution

-Bacteria and Nutrients from Livestock: Livestock live in confined areas which causes waste to collect in that area. Farms that do not properly manage this waste are harming the environment because runoff is carrying the bacteria and nutrients from the animals waste into water sources. Agricultural lands and farms surround much of the Conodoguinet Creek. One of the main issues with the nitrate levels in the Conodoguinet Creek is due to livestock manure and agricultural pollution.

-Urban Runoff: Water running off impervious surfaces including roads, parking lots, rooftops, sidewalks, or any developed land tend to pick up gasoline, motor oil, heavy metals, and trash, as well as fertilizers and pesticides from lawns, which have heavy amounts of nitrates. Inability to educate and provide alternatives to consumers attempting to wash their cars or dispose of household chemicals and motor oils are often cited as key factors in the problem, although one document put out by the Carlisle Borough blames the problem more generally on development and (sub)urbanization as the human population dependent on the watershed grows in size. This problem is particularly difficult for local government to tackle without impeding its own interests, and as new water treatment plants can process out most of the runoff, the runoff only impacts raw water quality, which remains spotty and frequently threatened. However, this is a large problem as large trucking facilities and warehouses along with nearby highways (U.S. Route 11) all drain into the Conodoguinet watershed, most of them lacking sufficient buffers or simply going through stormwater drains directly into tributaries.

-Sediment from Improperly Managed Construction Sites, Stream Banks, and Crop and Forest Lands If managed improperly, rain and melting snow cause pollutants (including nitrates, anthropologically formed from mainly from nitrogen combusting in petrol) Creating riparian buffers is one way to help control and manage this runoff.

-Malfunctioning Septic Systems: Largely rural and agrarian, approximately 7.1% of Conodoguinet Creek watershed inhabitants use on-site septic tank systems. When septic tanks malfuntion, human waste can leak into the environment and rain water could cause the nitrates from the waste to pollute near by streams. For this reason regular examinations and pumpings of septic systems are recommended.

Current Regulations on Nitrates in Conodoguinet Creek

Currently the amount of nitrates in the Conodoguinet Creek are regulated by the EPA's Safe Water Drinking Act and the Clean Water Act.

Safe Water Drinking Act:

Under the Safe Water Drinking Act the EPA has set standards on chemicals in treated drinking water. The standards were set by the EPA because excessive amounts of some chemicals do or may cause health effects when consumed. The levels that the EPA sets, which they believe are appropriate standards for chemical levels are called Maximum Contaminant Level Goals (MCLG). The MCLG levels are non-enforceable, however the EPA does have Maximum Contaminant Levels (MCL) that are based on the MCLG, and are enforceable Under the Safe Water Drinking Act the Conodoguinet Creek is mandated to have nitrate levels no higher than 10 parts per million after being treated by the water treatment plant. The problem with this is not that the treatment plant is not doing their job correctly, but often well water around the Creek tests at nitrate levels above 10ppm. The nitrate levels in the well water often tests above 10ppm because of runoff from point source and non-point source pollutants. The well water is not regulated under the Safe Water Drinking Act.

Clean Water Act:

The foundation of the clean water act was originally created in 1948 under the name of the "Federal Water Pollution Act". In 1972 it was revised and expanded, and then in 1977 amendments were made which earned it the the name the "Clean Water Act". The Clean Water Act has made it unlawful to discharge any pollutant from a point source into any navigable water sources unless a permit is attained. Under this law, the Environmental Protection Agency (EPA) has regulated point source emissions by implementing pollution control programs. The EPA's national pollutant discharge elimination system (NPDES), is the permit program that regulates discharges from point sources.

Link to clean water act: http://epw.senate.gov/water.pdf

Clean Water Act programs:

The Clean Water Act programs help control nitrate levels in the Conodoguinet Creek.

-National Pollution Discharge Elimination System (NPDES) Program

This program seeks to protect the health of the nations water sources by regulated point source polluters. The NPDES regulates approximately 15,000 publicly owned water treatment plants and about 85,000 industrial polluters. This program distributes permits, lasting five years long, that are distributed to single dischargers or group discharges. To obtain a permit the discharger must be able to control the pollution discharged, monitor emissions, and report discharges. As of the NPDES is able to distribute permits in 44 states and one territory also they are able to enforce compliance to the mandated standards by the EPA.

-The NPDES has four main subprograms under the name, wet weather enforcement programs. These subprograms are used to regulate discharges from wet weather such as runoff or rain. The four main subprograms of NPDES consist of the Combined Sewer Overflow Program (CSO), Storm Water Program, Concentrated Animal Feeding Operations Program (CAFO), and Sanitary Sewer Overflow Program (SSO).

Conodoguinet Creek

-Combined Sewer Overflow Program

These are a combined sewer system that allow industrial waste, human waste, and rain water runoff, to go through the same pipe. Most of the time these pipes lead to sewage treatment plants. However, during times of heavy rainfall the sewage plant that the pipes lead to sometimes overflow and the waste water is directly discharged to the water source without being treated. Because the waste water is not treated and is going directly to the discharge water source this is a major source of pollution. To ensure that communities with CSO's meet the CWA, the EPA created the CSO policy in 1994. This policy provides guidelines to communities with CSO so that they can meet the standards of the CWA in a efficient manner.

Link to CSO policy-http://www.epa.gov/npdes/pubs/owm0111.pdf

-Storm Water Program

This program regulates storm water discharge from three different areas which include municipal separate storm sewer systems, construction activities, and industrial activities. These three different areas may be required to attain a permit depending on the size of their operations. With storm water runoff being considered a point source for pollution, discharging it into a stream requires a permit under the NPDES. To receive a permit the operator of the runoff system must show that they are able to treat and regulate the storm water runoff. The EPA has created guidelines to help operators do the best they can in regulating storm water runoff. Also best management practices (BMP's) such as the National Menu of BMPs and the Urban BMP Performance Tool were also created to help operators meet the EPA's standards.

Link to EPA's storm water regulation page-http://cfpub.epa.gov/npdes/home.cfm?program_id=6

-Concentrated Animal Feeding Operations Program

CAFO's are simply Animal Farm Operations (AFO's) that are certified by that EPA. AFO are difined by the EPA as "agricultural operations where animals are kept and raised in confined situations. AFOs congregate animals, feed, manure and urine, dead animals, and production operations on a small land area. Feed is brought to the animals rather than the animals grazing or otherwise seeking feed in pastures, fields, or on rangeland." To be a certified by the EPA as a CFAO, an AFO must first meet the EPA definition of a AFO and second it must meet the one of the regulatory definitions of large CAFO, medium CAFO, or small CAFO.

Link to Regulatory Definition of large CAFO, medium CAFO, and small CAFO-http://www.epa.gov/Region7/water/cafo/index.htm

-Sanitary Sewer Overflow Program

SSO are when a sewage treatment plant overflows and and the overflow is that is untreated is discharged in to the water source. There are various causes of SSO including malfunctioning facilities, bad weather, or mismanagement of operations. The water that overflows can not only pollute out water sources, it can also back up into a houses basement, which also can effect the health of people. To help avoid SSO's, the EPA requires permits for sewage treatment plants to discharge treated water. To aquire a permit a plant must meet EPA standards that show that they are doing what they can to avoid SSO's.

-Pretreatment Program-

The Pretreatment program has two main purposes. The first purpose is to stop the introduction of new pollutants that will harm the plant operations and to stop pollutants from going untreated, from publicly owned treatment works (POTW). The second purpose is to improve the opportunity that POTW’s have to reuse wastewaters and sludge that are generated form their plants. The federal, state, and local governments work together to ensure that these two purposes are met. The industries pre-treat their waste discharged into sewage treatment plants. The pretreatment program saves the local sewage systems from millions of dollars in investments of upgrades in facilities because industries pre-treat their discharges.

Link to pretreatment regulations for PA-http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=2f4c44d9fa1bf64016d209d1543dd5cc&rgn=div5&view=text&node=40:28.0.1.1.4&idno=40

-Biosolid and Sludge Program-

The Biosolid and Sludge program was created to regulate the use and disposal of sewage sludge. This was done through part 503 regulation of the CWA. This program applies to the disposal of biosolids and sludge in land disposal, surface disposal, incineration, and landfills. In each of these methods there are standards that must be met such as meeting requirements, limiting pollution, operating up to standards, record keeping and then reporting records.

Link to Biosolid and Sludge Program regulations for PA-http://www.pacode.com/secure/data/025/chapter271/subchapJtoc.html

-Wetlands Dredged and Fill Material Program-

This program created under section 404 of the CWA, mandates that waste is not discharged into wetlands and other water sources unless a permit authorizes it. The Army Corps of Engineers must authorize the permit. Because wetlands are such an important part of the environment permits are strictly given out. The EPA and Army Corps of Engineers agreed that in terms of enforcement they should focus on discharge that is not allowed by permit.

Link to CWA section 404 that sets the regulation laws-http://www.epa.gov/owow/wetlands/regs/sec404.html

-Oil and Hazardous Substances Spills Program-

This program was created from section 311 of the CWA. The focus of this program is a joint effort by the EPA and U.S. Coast Guard to deal with pollution from oil and other hazardous substances. Through this program the EPA and U.S. Coast Guard are able to prepare and act in the case of an oil spill or other hazardous spills that will affect U.S. water sources. The EPA and U.S. Coast Guard are able to enforce penalties in the event that an oil spill or other hazardous substances spill. Penalties are enforced for spills of oil and hazardous substances and also for violating methods used for prevention and responses to spills. The penalty in the case of a spill of oil and hazardous substances are $1,100 per barrel of substance and for violating prevention and response methods the penalty could amount to $27,500 per day.

Solutions:

Enforced regulations

The regulations of the Biosolid and Sludge Program created from the CWA has many strict regulations. These regulations make using biosolids as a fertilizer a very good practice; however there are some regulations within this program that could be stricter to better regulate nitrates going into the Conodoguinet Creek. The first regulation that could be made stricter is that farmers have to be a certain distance from a water source, including wells, to be able to use biosolids for fertilizer. If this regulation were to be made stricter much of the problems from nitrates going through the ground and then making there way to the Conodoguinet Creek would be gone. A suggestion to help reduce nitrate pollution would be to make it mandatory that farmers be a required distance from water sources so that only a limited and manageable amount of nitrates reach the the Conodoguinet Creek. Another regulation that could be made stricter is how much biosolids are used as fertilizer per acre for farming. Although there are strict regulations to control amounts of biosolids that go on fields, these regulations are either not followed by the farmers, or the regulations themselves allow to much fertilizer. The first problem could be addressed through education of the farmers. This idea will be discussed more in-depth in the following paragraph. The second problem could be addressed through even stricter regulation with strong enforcement and penalties. The amount of fertilizer a farmer receives should be based not only on how much land it is being used for but for the specific type of crop.

Education for Non-Point Source Polluters

Much of the time policies and regulations on farmers and the amount of fertilizer they are allowed to use are set at levels that are beyond what is actually needed for their crops. Through education farmers would no longer be using unnecessary amounts of fertilizer on their crops. Not only would this save money for the farmers because they are using less fertilizer, they would also be damaging the Conodoguinet Creek less because of the reduced amounts of nitrates going into the creek through runoff. The Department of Environmental Protection (DEP) already does educate farmers on what they should be doing, however with the current condition of the Conodoguinet Creek it leads one to believe maybe more education is needed. To make sure the farmers are fully understanding what they should be implementing in their farming practices, the government could make it mandatory for farmers to pass a “farmers test” every few years. By making it mandatory it forces the farmers to be educated about nitrates and the damages they cause, but also by having a mandatory test every few years it will insure the farmers stay updated on how they can reduce the amount of nitrates they place on the environment. An incentive for farmers to pass the test could be that the government makes it mandatory to pass the test if you want to sell your crops to the public.

Another way for non-point source polluters to control the amount of pollutants entering the stream would be by creating stronger buffering systems. Planting shrubs, tree lines, and other buffering systems will help manage the amount of nitrates and other harmful pollutants that enter the stream.

Agricultural Best Management Practices

Following the completion of a watershed assessment and cost estimate of agricultural nutrient and sediment controls conducted by the Cumberland County Conservation District in the early 1990s, the district gained the cooperation of many farmers and landowners for installing agricultural Best Management Practices (BMPs) to reduce nitrate runoff, among other goals. Many farmers have participated in incentive programs for nutrient and animal waste management and conservation planning; however, the EQIP initiative of the U.S. Natural Resource Conservation Service, the organization that was funding, organizing, and providing technical support to this initially encouraging program, had its funding cut rather badly during the Bush administration and later under President Obama. Applications for grants to control nutrient and waste runoff in the Conodoguinet watershed are therefore a recommended goal of watershed organizations and conservation districts.

Several interesting and successful initial grants under the EPA Clean Water Act Section 319 have included: • $40,112 (FY2002) to Cumberland County Conservation District to implement agricultural best management practices (BMPs) on farms in the Bulls Head Branch watershed. • $387,525 (FY2001) (BMPs) on selected farms within impaired reaches of Conodoguinet Creek tributaries to reduce the amount of nutrients and sediment entering Conodoguinet Creek. BMPs include manure storages, roof runoff, field conservation practices and stream bank protection. • $205,000 (FY2001) to Franklin County Conservation District to implement best management practices (BMPs) on selected farms within impaired reaches of Conodoguinet Creek tributaries to reduce the amount of nutrients and sediment entering Conodoguinet Creek. BMPs will include manure storage structures, barnyard runoff control, sediment basins, filter areas, and nutrient management assistance.

Potential benefits of incentive-based BMP reform are numerous and diverse, as there is much room for improvement. Streambank stabilization and fencing will likely reduce nitrate and sediment loads by slowing erosion. Fencing will keep livestock out of the stream and build up riparian zones to trap sediment and nitrogen, while contour farming and grass waterways can reduce storm runoff. Manure management practices should also be implemented on cattle farms to reduce runoff of manure from animal feeding and milking areas.

Education for Point Source Polluters

Education could also be used to teach industries about how they can use different materials that are less harmful towards the environment, upgrade their facilities to cause less environmental damage, and how in taking these steps in the long run may help their facility run more efficiently and save money.

Technological Advances

Currently the Carlisle sewage treatment plant is constructing a new technological advancement that will allow them to have zero nitrate emissions. The new technology in this facility allows the nitrates to go through a process known as denitrification. Denitrification is the process in which nitrates (NO3) are returned to the atmosphere in their original form of N2 and NO2. With this ability the sewage treatment plant can now remove nitrates through denitrificaiton instead of sending the nitrates away in the form of biosolids or emitting them into the Conodoguinet Creek.

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Image: Point source vs. non point source: http://connecticutwatertrails.com/CWTA%20-%20Connecticut%20Water%20Trails%20and%20Water.jpg(accessed 12/3/2009)

Image: PA Department of Environmental Protection;Biosolids: www.depweb.state.pa.us/biosolids/site/default.asp

Image: Conodoguinet Creek Picture: 400 x 300 - 47k - jpg - 4.bp.blogspot.com/.../s400/29+(Medium).JPG (accessed 12/3/2009)

Image: Algal Bloom Picture: http://plants.ifas.ufl.edu/guide/bloom1.jpg (accessed 12/3/09)