This paper was written as part of the 2004 Alaska Ocean Sciences Bowl high school competition. The conclusions in this report are solely those of the student authors.
Up the Creek Without a Paddle: Home Septic Systems in the Matanuska-Susitna Borough
Table of Contents
Residential development is the most important challenge facing our community and the coastal ecosystem supporting that community. The Matanuska-Susitna Borough (MSB) is the fastest growing community in Alaska, with a population increase of almost 10% in the last two years. We believe that the biggest pollution problem facing our coastal community is septic system leakage from home septic systems. Ground and surface water contamination will increase with the population increase.
Biomagnification is the word scientists use to explain why animals that eat other animals have higher levels of contaminants than animals that eat plants. Some contaminants are persistent, once they are in the animal's body, they stay there for a long time. So when smaller animals are eaten by bigger animals, all the contaminants stored in their tissues are then passed on to the bigger animal.
Pollution from septic systems is transported both from surface run-off and from leakage into the area's shallow depth aquifers. There are currently no borough requirements for regular testing for water quality for small homeowners. Surface water is usually considered more susceptible to contamination than groundwater.
Our local risk assessment study and plan is three pronged:
The Matanuska Sustina Borough (MSB) is 25,260 square miles in size (about the size of West Virginia). Of those 25,260 square miles, 24,682 square miles is land, and 578 square miles is covered by water, and it includes 413 miles of coastline. The coastal zone district of the MSB includes 4,149 square miles, following the major rivers and waterways up to an elevation of 1000' (Tour Alaska's Coast, 1998). According to Ken Hudson, the Matanuska Susitna Borough's coastal planner and the head of the MSB code compliance department, 90% of the population of the MSB lives between the communities of Big Lake and Palmer, along the road corridor, which follows the natural contours of the major river systems in the area. Hudson believes that the biggest challenge facing our area is balancing the growing population pressure with land use, and the most important contaminant problem facing our community is leakage from home septic systems into nearby stream systems and the shallow aquifer groundwater table (Hudson, pers. com.).
The borough contains the rich farmlands of the Matanuska-Susitna River valleys, created by till from retreating glaciers. It also includes portions of the Alaska Range, part of the Chugach Mountains, and almost all of the Talkeetna and Clearwater Ranges. The Susitna River drainage is one of the top salmon producing areas in the state. In Alaska, the leading export of resources was fish, a total of $1.231 billion in 1996 , which exceeds the value of petroleum exports, which totaled $762 million in 1996. Protecting resources from contamination should be a high priority for the borough and the state. The economic base of the MSB is diverse. It serves as a bedroom community for people employed in Anchorage (Alaska in Maps, 1999).
Alaska is one of the least populated states in the nation, but these demographics are changing, especially in the MSB (Table 1). In 1990, the total population of Alaska was 550,043, and the population of the MSB was 39,683. In 2000, the population total for the state was 626,932, and in the MSB, the population was 59,322. The increase in state population between 1990 and 2000 was 14%, and the increase in population in the MSB during that same time was 49.5%. Between 2000 and 2002, the population in the MSB increased by 8.9%, while the increase for the state as a whole was only 2.6% (http://www.ers.usda.gov/Data/Population/). The MSB is the fastest growing population center in the state, and one of the fastest growing population areas in the US. State labor economist Neal Fried said the MSB's best economic indicator remains its population growth.
"Between 1990 and 2002, Anchorage grew by about 19%. That's healthy growth. Meanwhile, Wasilla grew 57%, Palmer grew by 80%, and Houston grew by 84%. That's phenomenal growth" (Alaska Journal of Commerce, 2003). This is a staggering increase by percentage, and certainly a cause for environmental concern if population growth is not managed wisely.
If you own a home in Alaska, chances are that you own a septic system. A septic system is an effective method of household wastewater treatment. In addition, it is cost effective and easy to maintain. While one in four homes in the United States is on a septic system, the number is much higher in Alaska. Well-built systems can last 20 years or more when properly maintained (Figure 2).
Septic system failures are a major source of groundwater pollution, cause waterborne illnesses, such as dysentery and hepatitis, and are expensive for a homeowner to replace or repair. Groundwater pollution is often difficult to detect and to control. Problems with septic systems are worsened when communities that rely on subsurface disposal systems also depend on private wells for drinking water Groundwater moves slowly, but constantly, through cracks and crevices in the rock and pores in the soil. As the water moves, it picks up any pollutants with which it comes into contact. Since the water moves slowly, the pollutants might not be detected until it reaches your well and by then the problem may cover other community wells. In some cases, the water might be impossible to disinfect.
As many as one half of all septic tanks in operation are not functioning correctly (http://www.cee.vt.edu/program_areas/environmental/teach/gwprimer/gwprimer.html). When the soil capacity to absorb sludge is exceeded, wastewater from drain lines make their way to the surface and water runoff from rain can then contaminate surface waters and even improperly sealed wells down gradient. Pollutants from the drain field can also move through the soil too quickly and potentially contaminate groundwater. This problem can be compounded where aquifers are shallow, like many aquifers in the MSB.
Proper maintenance of your home septic system is critical to protecting your well water, and the surface waters around you. Knowing what NOT to put down your toilet is important. The following items can overtax and/or destroy the natural processes within your septic system. Do not dump household wastes such as coffee grounds, tampons, dental floss, cigarette butts, disposable diapers, condoms, kitty litter, fat, grease or oil, sanitary napkins, or paper towels. Do not dump any hazardous chemicals such as: paints, waste oils, varnishes, photographic solutions, thinners, or pesticides.
All homeowners should follow the maintenance guidelines from the Alaska Department of Environmental Conservation (ADEC) for optimum life from their home septic systems:
Groundwater contamination results not from the discharge of contact water, but from the leakage of this water from septic leach fields. Leakage increases over time, moreover, as systems get older and develop problems. Cracks can develop from above or below ground stress, deterioration, biological degradation, or by root intrusion. Wastewater can then infiltrate into the soil or groundwater through these cracks and contaminate the surrounding area. Contamination can also occur by sewer overflow.
Human feces are comprised of a significant portion of bacteria. The bacteria originated in the human gastrointestinal tract, which includes the stomach, small intestine and large intestine. The bacterial population found in the stomach is consisted mainly of lactobacilli and yeasts.
Bacteria can produce acids that can "eat" away the holding systems. Anaerobic chemoheterotrophs (use organic compounds as an energy source in absents of oxygen) and aerobic chemolithotrophs (obtain energy by oxidizing ammonia, nitrite, reduced sulfur compounds, and iron or manganese oxides) can cause acidic conditions in septic systems. Most of the acidic conditions occur in sanitary sewers. Corrosion in concrete sewer pipe is caused by the anaerobic production of hydrogen sulfide, which is then absorbed in the condensation on the walls above the water level. The aerobes then oxidize the reduced sulfur to sulfate, which forms sulfuric acid. The sulfuric acid then attacks and erodes the concrete usually to the outside soil. As the acid eats away the concrete, small stress fractures can be created and can result in the shattering of the pipe. Infiltration of wastewater into the soil and possibly the groundwater can then occur.
Excessive Biological Oxygen Demand (BOD) in sewage fluids may enhance anaerobic conditions in groundwater areas and cause significant contamination and water quality problems (http://k12science.ati.stevens-tech.edu/curriculum/waterproj/bod.shtml).
Domestic sewage, in itself, contains a complex mixture of inorganic compounds which are potentially harmful to groundwater quality. Major constituents include nitrogen and phosphorus which, in excessive concentrations, present a great threat to groundwater quality. Potentially toxic metals, such as lead, copper, tin, iron, zinc and manganese may be found in high concentrations from human wastes and also occur from deterioration of household pipes.
Once the wastewater has infiltrated into the soil, the groundwater can transport the contaminants through several different mechanisms: (Figure 3)
Adsorption-the separation of organic contaminants from the soluble phase onto the soil matrix. The contaminants move through the soil matrix and some of the contaminant's particles "adhere" to soil particles. Most contaminants that are absorbed are hydrophobic in nature. The more hydrophobic the contaminant is then the less soluble it is in water.
Advection—the movement of contaminants that move along with the bulk flow at the seepage velocity in porous media. The seepage velocity is the same as that of the average linear velocity of a contaminant. The groundwater usually moves in the horizontal direction, and carries the bulk of contaminant down gradient from the source of pollution.
Biodegradation—the transformation of certain organic compounds to simple CO2 and water in the presence of microbes in the subsurface. The transformation is a biochemical process that deals with electron acceptors and donors. In aerobic environments the organic contaminant is the electron donor and oxygen is the electron acceptor. This means that when the organic compound comes into contact with oxygen, oxygen gains electrons and the organic compound is reduced (loses electrons).
Diffusion—molecular mass-transport process in which solutes move from areas of a higher gradient to areas of a lower gradient. Mass-transport can also occur due to differences in energy levels (higher to lower).
Dispersion—mixing process caused by differences in groundwater and contaminant velocity in the porous media.
Many methods of remediation exist and include chemical, physical, and biological treatments. Physical treatment involves using barriers and surface water controls. Barriers used include slurry walls, grouting curtains, sheet piling, and passive interceptor systems. Surface water controls are used to minimize the infiltration of surface water/precipitation to the groundwater. Chemical treatment is done by using the following processes: neutralization, ion exchange, redox reactions, and precipitation. Biological treatment uses microorganisms that may be contained in activated sludge or anaerobic digesters.
Alaska has the greatest ground water resources of any state in the United States. Ground water resources are used for most domestic needs around the state. Ground water supply aquifers range from extremely small thaw bulbs in permafrost to large regional aquifers. The extensive permafrost development around the state provides challenges to the development of ground water resources. In many parts of Alaska, steep topography limits the size of most aquifers, preventing large scale.
Fecal coliform bacteria, sediment, and petroleum products are the primary pollutants of surface waters in Alaska. When there is a septic runoff, the groundwater is affected heavily, and in some instances more than just the ground water. When the sewage gets into the groundwater, it moves with the water, and in some cases it can come back into your home affecting your health, however in other situations it can affect the entire food chain (http://www.who.int/docstore/water_sanitation_health/wqmonitor/ch04.htm).
Sewage contaminants can bioaccumulate in the food chain, and damage natural resources and one of Alaska's primary income sources. Spawning salmon pick up lipids in the water to give them energy to swim upstream and spawn. If the water were contaminated, the lipids that the salmon pick up would carry small degree of that sewage, and as the salmon move on they pick up more lipids, hence more sewage in their system. When the salmon spawn and lay eggs, some of that pollution is passed on in the eggs, so anything that eats those eggs then gets a degree of pollution. For example, stream trout, or grayling, and in them the bacteria doubles until they die or are consumed by birds or even humans. When that happens the consumer gets polluted to a higher degree than the fish. What about the dying salmon? Well all those eagles that come to feed on the carcasses get polluted as well. So what started as a simple sewage leak has moved from the water to the salmon, and from the salmon to the eagles, trout, and grayling, then to anything else that comes across a dead carcass that was polluted, could be anything from mice to a fox, and eventually it comes back to us (Figure 4).
Eventually, the leakages from septic systems will get in to the rivers and streams and flow down into the wetlands. Wetlands are a breeding place for all types of animals, and they are also drain out into the oceans, dumping all of the pollutants into the oceans.
When sewage comes in contact with humans, it can be very harmful. Sewage can contain viruses like hepatitis, cholera, typhoid, and Salmonellosis among others. E. Coli is the easiest bacteria to test for, it is common in human and animal feces, and is a good indicator that water is contaminated by some source of sewage. While most strains of E. Coli are relatively harmless, it's presence in water can indicate more serious contaminants that are more difficult to test for directly (http://www.moldlab.com/sewage_screen.htm).
There are five types of hepatitis; hepatitis A, B, C, D, and E. All five types of hepatitis are viral liver diseases of which there are only vaccines for A and B. Good hygiene and sanitation are good preventatives of hepatitis. Some of the symptoms of hepatitis are jaundice (yellowing of the skin), fatigue, abdominal pain, nausea, diarrhea, fever, loss of appetite, vomiting, joint pain, and dark urine. Once you have had hepatitis A you can not get it again. There is a 2 week to 6 month incubation period for hepatitis. Hepatitis A and E are found in the feces of people with hepatitis A or E. Hepatitis B, C and D are found in the blood or body fluids in an infected person.
For hepatitis A, there is no chronic, long-term, infection and about 15% of people infected with HAV will have prolonged or relapsing symptoms over a 6-9 month period. For hepatitis B, chronic infection occurs in 90% of infants infected at birth, 30% of children infected at age 1-5 years of age and in 6% of people infected after five years of age. Death from chronic liver disease occurs in 15-25% of chronically infected people. For hepatitis C, chronic infection is in 75-85% of infected people. Chronic liver disease is in 70% of chronically infected persons. Less than 3% of people infected with hepatitis C die from chronic liver disease. Hepatitis C is also the leading sign for the need of a liver transplant. Hepatitis D coexists with the Hepatitis B vaccine only. Hepatitis D can become chronic and have high a risk of liver disease.
Cholera is a diarrheal illness that is caused by an infection in the intestine. It is caused by the bacterium Vibrio cholerae. There are times that the infection is severe but mainly the infection is mild or without symptoms. About one in twenty people who are infected with cholera have severe cholera. The symptoms of severe cholera are copious watery diarrhea, vomiting and leg cramps. In the people with severe cholera, the loss of body fluids can lead to dehydration and shock. If severe cholera is not treated, the infected person could die within hours.
A person may be infected by cholera by drinking water or eating food that has been contaminated with the cholera bacterium. Cholera is spread rapidly in areas with insufficient management of sewage and drinking water.
Salmonella typhi resides only in humans. People with typhoid fever, have the bacteria in their bloodstream and intestinal tract. There are some people, known as carriers, who recuperate from the typhoid fever but continue to carry the bacteria. The ill people and the carriers give off S. Typhi in their stool.
You can get typhoid fever if you come in contact with food or drink that has been (or is) near sewage-contaminated water. Typhoid fever is more relevant in areas of the world where people don't usually wash their hands and water is likely to become contaminated. Once S. Typhi bacteria are in the body, they increase in numbers and stretch into the bloodstream. The reactions of the body include fever with a temperature of 103°F to 104°F, the body may become weak, there may be pains in the head and stomach, there could also be a loss of appetite. In some cases, people have had a rash of flat, rose-colored spots.
The bacteria called salmonella cause salmonellosis. The symptoms of salmonellosis are diarrhea, fever, and abdominal cramps. These symptoms usually start around 12 to 72 hours after the infection. In some cases, the diarrhea is so severe that the person is hospitalized. In these cases, the infection may have spread from the intestines to the blood stream and then to other sites in the body. Unless the person is given antibiotics soon after the infection, death can occur. People who are elderly, infants, and those with an impaired immune system are more likely to have a severe illness.
Salmonellosis can usually resolve itself in 5-7 days. It often does not need treatment. The times that the patient would need treatment is when they become dehydrated or the infection spreads from the intestines. People with severe diarrhea may need to be rehydrated, sometimes with intravenous fluids. When the infection spreads from the intestine, then antibiotics can be used. Some of the antibiotics that might be used are ampicillin, gentamicin, trimethoprim/sulfamethoxazole or ciprofloxacin. Some of the salmonella bacteria have become opposed to antibiotics (http://www.cdc.gov/).
Groundwater is the source of drinking water for about 50% of Alaska's total population, and about 90% of the rural population (http://www.state.ak.us/dec/deh/dww/pdf/groundwater.pdf). Protecting groundwater aquifers from sources of contamination should be a high priority for all Alaska residents. Alaskans use about 60 million gallons of water daily, 30 million gallons from groundwater, and about 30 million gallons from aboveground sources (http://www.state.ak.us/dec/acwa/brochure/acwa.pdf).
Properly maintained septic systems are a key component for reducing possible points of contamination. Educating the public in how to install and maintain their septic system is a key component for our plan to reduce contaminants in our area. The majority of private homes in the MSB operate on some type of home septic system. The well and septic system is a valuable part of the homeowners property, and we will encourage people to become educated about how to properly maintain their home systems. A recent scandal in the MSB highlighted the problems that the borough's lack of mandatory testing of septic installations by the ADEC. A contractor built hundreds of faulty installations for local homeowners, then absconded with their money. With no oversight by the ADEC of installation of septic systems and wells, the problem was not recognized until the septic systems backed up either into the house itself, or actually came up to the surface (http://www.ktuu.com/archives/html/modules.php?name=News&file=article&sid=2518 ). The ADEC already has published guidelines on proper maintenance of home septic systems. Having homeowners vested in maintaining systems that are currently operating properly, and replacing faulty systems will be the primary focus for reducing the contaminant source to our local area.
The primary concern we have in the MSB is the increasing density of housing in areas that may not have adequate drainage soils for a home septic system and septic systems located to close to surface water. Valuable residential properties tend to be around water sources, including rivers, lakes, wetlands and streams where there is a more likely pathway for contaminants to flow through the soils and into the water systems if sufficient set-backs are not in place and enforced. Faulty systems can also back up contaminants to the surface, and rainwater will wash the effluent down into surface waters. Currently, there is no mandatory well and septic testing system in place in the MSB. Most bank lenders, however, do require a well and septic system check before financing will be provided for home loans. Drain fields in home septic systems can become faulty if not properly maintained. Periodic testing of well water is the best way to monitor if contaminants are getting into aquifers and drinking water.
To reduce contaminant sources to aquifers, we can start by testing well water and septic systems in high risk source areas, such as large subdivisions. ADEC already has a data base of well water test results that can be compiled on a geographic information system (GIS) for mapping areas of concern. GIS information can be compared with currently known aquifer systems to look for patterns of contamination. After we compile information on what kind of septic systems cause the most problems, we can ask that residents to bring their systems up to a code that works for that area, or switch to a public water and sewer system. As the population grows, public water and septic systems will likely become the norm for the MSB. Currently, the Department of Environmental Conservation (DEC) mandates public well and septic systems for properties with insufficient acreage to support a typical home septic system. (The Updated Plain English Guide to Alaska Drinking Water and Wastewater Regulations). Current regulations require 100' setbacks from above ground water sources and well and drinking water sources, other regulations may apply, depending on subsurface soil types and ground conditions (18 ACC 72 Wastewater Disposal). According to Mr. Hudson, many older properties do not even meet these minimal requirements (Hudson, pers. com.).
Our plan would be to phase in eventual periodic testing of ALL drinking water systems in the Borough, and to follow up with remediation for any areas that test positive for well water contamination of any kind. Testing well water is very inexpensive. Follow-up testing for septic system problems is more costly, but necessary if contamination is found. The serious human health risks and environmental risks for drinking water contamination are a sufficient mandate for this plan.
Many local lakes already have monitoring systems in place for water quality. We are networking with the Wasilla Soil and Water Conservation Service (ASWCA), an agency attached to the US Department of Agriculture, to determine where to set up monitoring stations to collect water quality data for streams. We have set up points above and below large subdivisions, at main road crossings, and at the headwater and the mouth of Wasilla Creek to monitor for contaminants. AWCA has agreed to supply testing equipment and training for a preliminary baseline study, and then to follow up with their citizen monitoring program to continue to monitor areas that show possible problems. Fecal Coliform, Nitrate (NO3), Nitrite (NO2), Chlorides, and Phosphates are common pollutants from septic leakage. If Wasilla Creek is determined to have a significant contamination problem, we will nominate the creek for inclusion to the Alaska Clean Water Action (ACWA) as a "stream in need of study", which can provide access to additional funding for further study of the waterway (http://info.dec.state.ak.us/awq/awca/waterbody/acwa1_interface/Results/submission_form.asp).
In summary, we believe that taking a proactive stance in having homeowners monitor their own systems, educating the public about proper maintenance, and phasing in ADEC regulation of well and septic systems will reduce the contaminant source for septic pollution in the MSB. Setting up a system to test and monitor wells to detect groundwater pollution will pin-point areas that need further testing or remediation. Continuing to monitor lakes, and doing a baseline study of critical areas of local streams will provide the basis for determining where possible sources of contamination are present, and provide a means to further reduce the source. It would only cost the home owner $25.00 a year to test their well water, and the information found through well water testing can be used to keep an eye out for septic tank leakages. This three fold process is cost effective, and is also necessary in order to protect our local waters for future use and enjoyment.
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