The Clean Water Actdefines “pollution” as the “man-made or man-induced alteration of the chemical, physical, biological, or radiological integrity of water.” More general pollution includes any alteration in the character or quality of the environment, or any of its components, that renders it harmful or less suited for certain uses.
Point Pollutioncomes from an identifiable source such as an industrial discharge pipe, an underground storage tank, sewage treatment plants or even agricultural feed lots and manure storage areas.
Non-Point Pollutiondoes not originate from one specific location, and it often discharges over a wide area of land. For example, as rain water flows across lawns, farms, streets, parking lots, and other surfaces, it carries salt, pesticides, fertilizers, oil, grease, and many other pollutants to nearby waterways. The source of any one pollutant cannot be identified.
5 Major Pollution Catagories
Pathogenic Organismsare disease-causing organisms that are found in human intestines and, therefore, are found in human waste. These organisms cause a variety of diseases, and can be contracted when people drink water containing a sufficient number of these pathogens, which cause infection. Since the disease- causing organisms are difficult to measure in the laboratory, non-pathogenic bacteria – which can be easily detected- are measured to determine the quality of the water. These bacteria are called fecal coliforms. Fecal coliforms are harmless inhabitants of the human intestine and are present in great abundance when waters have been contaminated with sewage. When high levels of fecal coliforms are detected, there is a high probability that pathogenic organisms are also present.
Oxygen Demanding Substances. Oxygen is required by most living things, including organisms that live in the water such as fish, insects, microscopic animals, and bacteria. Oxygen is also needed for the decay of organic matter. Decay is the process in which bacteria and microscopic animals break down and consume organic material such as flesh, leaves, or fecal matter. The amount of oxygen needed for the decay process is call the biochemical oxygen demand, or BOD. When given as a concentration, such as parts per million, it is a measure of the oxygen that is needed in a given volume of water for the decay process to occur. When large amounts of organic waste material enter surface waters, bacteria multiply, and decay can occur at a rapid rate. This can deplete the oxygen in the surrounding water to levels below that which is needed by living organisms. Organic wastes can come from human and animal sewage, agricultural practices, food processing, wood and paper mills, and numerous other sources.
All living organisms requireNutrientsfor growth. However, when nutrients are present in abundance in surface waters, nuisance or excessive growth of aquatic organisms, such as algae, can occur. When the excess vegetation decays, it uses and removes the dissolved oxygen from the water being decomposed by bacteria, resulting in high levels of BOD (biochemical oxygen demand). The nutrients of greatest concern are phosphorus and nitrogen. Both are naturally present in surface waters and both are present in abundance in wastewaters. Of the two – phosphorus is naturally in the shortest supply. When additional phosphorus is available, the growth rates of vegetation increases significantly. This can produce nuisance growths of algae and can cause changes in the species composition of aquatic plant and animal communities. It can also accelerate the eutrophication processes. Eutrophication is generally associated with increasing plant growth and the slow filling of lakes with sediment and organic materials. Nitrogen, on the other hand, often occurs in the form of ammonia and is a common constituent of sewage because it is a byproduct of the decay of organic material.
Suspended solidsare particulate material suspended in water, making it cloudy or turbid. The matter can be composed of sediment particles such as clay or sand, or of organic material such as decaying plant or animal matter. Matter such as organic material, phosphorus, heavy metals and some toxic substances tend to adhere to suspended solids. As a result, suspended solids have various adverse effects on water. Some heavy metals, most notably lead and a majority of the carbon-based toxic substances such as pesticides and polychlorinated biphenyls (PCB’s) tend to adhere strongly to sediment particles in the water. In this way, they can be easily transported from one site to another. However, they can also be removed from the water column by settling.
Toxic Substancesinclude heavy metals and organic chemicals used in manufacturing and agricultural practices. When present in water – even in very small amounts – these materials can produce a variety of serious human and environmental problems. Furthermore, many toxic substances do not break down or decay quickly in the environment. There are currently 17 toxic metals of particular environmental concern:Ag silver, As arsenic, Bi bismuth, Cd cadmium, Co cobalt, Cu copper, Hg mercury, Ni nickel, Pb lead, Pd palladium, Pt platinum, Sb antimony, Se selenium, Sn tin, Te tellurium, Tl thallium, Zn zinc.
What are PBTs?Persistent, Bioaccumulative, Toxic substances, or PBTs, are chemical pollutants that raise special challenges for our society because of their unique properties that require special attention.
PBTs are persistent.PBTs are chemicals that last a long time in the environment. In other words, either they do not break down into safer components, or they do not break down as easily or as quickly as non-PBT chemicals. They may even go undetected for a long period of time because their initial concentrations are so small, yet they can build up to harmful levels in humans, other organisms, and the environment.
PBTs bioaccumulate.Animals and people accumulate PBTs in their bodies, primarily from the food they eat, but also from inadvertent ingestion and inhalation of soil and dust. As these chemicals move up the food chain, they increase in concentration to levels that may be harmful to human, wildlife, and ecosystem health. Regardless of an individual’s eating habits, we as humans reside at the top of the food chain and are most at risk for increased PBT concentrations in our bodies and the adverse health effects that they cause.
PBTs are toxic.PBTs are toxic substances that can cause a wide range of adverse health effects in fish, wildlife, and humans. They have been linked to nervous system, reproductive, and developmental problems, immune-response suppression, cancer, and endocrine disruption.
Previous Uses: Commercial use of PCBs began in 1929 and was widespread. The manufacturing of PCBs (or PolyChlorinated Biphenyls) was stopped in 1977 (in the United States). Major uses of PCBs included: insulation for electrical cables and wires, coolants and lubricants, and in the production of electrical condensers.
Health Concerns: PCBs are considered to be probable human carcinogens based on its association with liver tumors in laboratory rats. Recent EPA documents have termed the findings of some human studies as “suggestive” of an association between human cancer and PCB exposure. PCBs are also associated with immunological effects in animals and some developmental effects in humans. People who have been exposed to PCBs for a long time have problems such as irritation of the nose and lungs, and skin irritations consisting of acne and rashes.
Ecological Effects: PCBs are another example of a highly persistent, highly lipophilic organochlorine contaminant. The degree of chlorination plays a role in the toxicity of PCBs to fish and wildlife. The higher chlorinated congeners appear to be less toxic to aquatic organisms but more toxic to birds and mammals. Birds appear to be more resistant to the acute toxicity of PCBs when compared to mammals, but are susceptible to the reproductive effects. Sublethal effects of PCB exposure include skin lesions, wasting syndrome, immunotoxicity, reproductive toxicity, genotoxic and epigenetic effects. Growth disorders and delayed reproduction and reproductive impairment are also linked to PCB exposure.
Fishing is a great Wisconsin tradition. So is eating your catch. However, some fish may take in contaminants from the water that they live in and the food that they eat. Some of these contaminants will eventually build up in fish and in humans to levels that can pose a health risk.
Mercury and PCBs are the contaminants of greatest concern in Wisconsin’s fish. To reduce people’s exposure to these contaminants, the WDNR provides advice to help you choose what fish and how much to eat. This information is not intended to discourage you from eating fish, but should be used as a guide to eating fish low in contaminants.
Some fish contain elevated levels of contaminants as a result of historical and, in some cases, ongoing pollution by humans. Small organisms absorb these contaminants in the water and, in turn, are eaten by small fish. Big fish eat small fish and, in this way, the contaminants accumulate up the food chain so that top level predators, such as walleye and bass, contain the highest amounts of contaminants.
Since the 1970’s, the state has aggressively tested fish from Wisconsin’s waters and now fish consumption advisories for specific waterbodies are issued when the fish are found to contain contaminants at levels that may pose health risks to people who eat fish.
For information about fish advisories please visit theWDNR.