Water Pollution

1. Water Pollution By C. KohnAgricultural Sciences,Waterford WI

2. Aquatic Ecosystems • Aquatic ecosystems include oceans, lakes, rivers, streams, estuaries, and wetlands. • These ecosystems are easily distressed by pollution. • Surface water ecosystems are those found in rivers, wetlands, and lakes. • All precipitation eventually finds its way into a surface water ecosystem. • The area of land from which a body of water gets its water is known as a watershed. • Surface water ecosystems are critical to the survival of other kinds of ecosystems found on dry land. beavercountyconservationdistrict.org

3. Surface Water Ecosystems • Surface water ecosystems are vital for land-based animals. • Wildlife depends upon surface water ecosystems for food, shelter, and breeding. • They also can provide much needed water for birds and wildlife. • Surface water ecosystems are also important to the watershed connection. • They capture rainwater as it flows over the ground, reducing erosion and flooding. • By holding stormwater, ponds allow nutrients and other chemicals to be filtered from the water by plants and animals before it moves into rivers and lakes. • Source: http://www.marine.usf.edu/pjocean/packets/f00/nwq1.pdf

4. How Aquatic Ecosystems Work • Plants are vital to a functioning aquatic ecosystem. • At the base of the food chain are small aquatic algae called phytoplankton. These algae use sunlight to convert CO2 and H2O into sugar. • Tiny animals in the water, called zooplankton, use phytoplankton as a food source. • Zooplankton are consumed by aquatic insects called macroinvertebrates. • Larger animals such as fish, use zooplankton and macroinvertebrates as a food source. • Source: http://www.marine.usf.edu/pjocean/packets/f00/nwq1.pdf tutorvista.com

5. Aquatic Ecosystem Health • Discussion: How can you tell if a body of water is healthy? • What signs indicate whether or not an aquatic ecosystems is affected by a disturbance? • Visible signs of pollution, odor, dead fish, and poor taste (for drinking water) are all signs that a body of water has been affected by a disturbance. • Often, indications of pollution are much more subtle and require more testing than simply observing the water. • When determining if a body of water is affected by a pollutant, we cannot wait until the signs of are obvious and visible before we take action. • To wait this long could put the aquatic ecosystem at risk of irreparable damage. • Sometimes signs of a pollutant are not obvious even at dangerous levels. • For example, we cannot see, smell, or taste toxic levels of mercury. svsu.edu

6. Water Pollution • Pollution is defined as the introduction of a substance into a natural environment that causes instability, disorder, or harm to the ecosystem • Aquatic pollutants can be divided into two categories: • Point Source Pollution – this is pollution that originates from a single source • This could be a factory, failing sewage treatment plant, or a damaged sewer pipe. • Non-point Source Pollution – this is pollution that cannot be traced to a specific point because it comes from many individual places over a large, widespread area. • Agriculture is the largest source of non-point water pollution. • Parking lots, suburban lawns, and roads also are common sources of non-point pollution. azine.noaa.gov

7. Biomagnification • Some pollutants are more of a concern because of the process of biomagnification. • Biomagnification: the process in which pollutants become more and more concentrated in living tissue. • Biomagnification enables a pollutant that is found in small amounts in the environment to become highly concentrated in the tissues of large organisms. • This can cause those organisms to become adversely affected by what may seem like a small problem in the environment. web.bryant.edu

8. Biomagnification • Biomagnification occurs because the pollutant will become stored in the bodily tissue of every organism that consumes it. • A toxin will first be absorbed in small amounts by phytoplankton. • Species at the bottom of the food chain (like zooplankton & aquatic insects) will eat large amounts of this phytoplankton. • Small fish will eat large amounts of these zooplankton & macroinvertebrates (insects), and these small fish will be eaten by larger game fish.

9. Biomagnification • Biomagnification increases with every step in the food chain. • Macroinvertebrates & zooplankton will eat many, many phytoplankton. • Many of these insects, which have eaten many, many phytoplankton, will be eaten by small fish. • All of the pollutants absorbed by the phytoplankton were trapped in the tissue of the insects and are now in the bodies of the fish. • All of the pollutants trapped in these fish will become trapped in the bodies of larger fish and other large predators (including mammals, birds, and humans). mhhe.com

10. Biomagnification • Three characteristics are necessary in order for a pollutant to biomagnify: • 1. The pollutant must be long-lived– if the pollutant breaks down too quickly, it would pass out of the tissue of living organisms • 2. The pollutant must be concentrated in organisms at the base of the food chain – usually biomagnification starts with a photosynthetic organism or an animal that is widely consumed by other animals. • 3. The pollutant must be fat-soluble– this allows it to be stored in the tissue of living organisms. • Water soluble substances are passed out of animal bodies when they urinate. • Only fat soluble substances can be stored in the body and accumulate.

11. Biomagnification • Each time a toxin goes up a level in the food chain, it becomes more and more concentrated in the tissues of living organisms. • Because humans are at the top of the food chain and live long lives, we are most susceptible to fat-soluble toxins. • These are toxins that are able to be stored for long periods of time in body fat and tissue.

12. Biomagnification • Many pollutants that biomagnify interrupt the ability of an organism’s body to function. • Lead, mercury, and heavy metals all can biomagnify and can cause nervous problems, infertility, and birth defects. • Hunters should never use lead-based ammunition, and lead sinkers should never be used by fishermen because of these concerns. • This may not seem like a big deal because the amount of lead lost by these objects may seem small and insignificant. • However, even a small amount of lead will bioaccumulate over time (such as in this bald eagle dying of lead poisoning). raptoreducationgroup.blogspot.com

13. Mutagenic Pollutants • Other pollutants can be mutagenic and interfere with a living organism’s DNA. • DNA is basically the instruction manual for a living organism’s cells. • When a mutagenic pollutant is present, it can interfere with the instructions given by DNA, causing birth defects, cancer, and other adverse health effects. • If the instructions for your cells to operate are changed, your cells will not function normally. • This is exactly how a mutagen and can cause tumors, infertility, developmental problems, and other serious issues in both humans and animals (such as the 5th leg on this frog). cgee.hamline.edu

14. PCBs • PCBs are a good example of a mutagenic pollutant. • They were used because they were not flammable, were very chemically stable, did not melt easily, and were great insulators for electrical wiring. • They were widely used in paints, plastics, rubber products, dyes, and many other industrial applications. • PCB’s were manufactured from 1929 until they were banned in 1979. • Despite being banned in 1979, PCBs still enter the environment due to improper disposal of old equipment, leaking hazardous waste sites, and the burning of wastes. • Once released, PCBs break down very slowly and are easily carried all around the world by rain, snow, and water. chem.unep.ch

15. PCBs • If ingested in high enough levels, PCBs can cause cancer, weaken the immune system, reduce birth weights, lower fertility, and cause neurological problems. • PCB levels in top predators such as bald eagles, lake trout and humans can be millions of times those found in surface water. • Every time a large predator consumes their prey, they increase the concentration of toxins in their bodily tissue if they are in an area affected by biomagnification. • As a student in Wisconsin, you too are a large predator in an area such as this!

16. PCBs • Because PCBs can be stored in body fat, they stay can build to harmful levels over time. • This can have a major impact on children because they are still developing. • This is why children and pregnant women are advised to minimize their consumption of large fish. • 30 years after they were banned, PCB’s are a major concern even today. • E.g. as recently as October 19th, 2009 dredging of the Fox River in Green Bay was halted to prevent the spread of PCBs. • However, if the Fox River cannot be dredged so that ships can easily pass through, it may seriously affect the 650 jobs and $75 million that shipping on this river contributes to Green Bay. • The impacts of water pollution are economic as well as environmental and health-related.

17. Eutrophication • A substance does not have to be toxic or mutagenic to be a pollutant. • Fertilizers are a major source of water pollution and are not nearly as toxic or mutagenic as some more commonly known pollutants. • Agricultural fertilizers are a concern because they can cause an ecological problem that other pollutants cannot – eutrophication • Eutrophication is the process in which the levels of water nutrients become too high, eventually causing dissolved oxygen levels in the water to become too low.

18. Eutrophication • The process of eutrophication involves a complex series of steps. • In a way, eutrophication is sort of like a set of falling dominoes. • When dominoes fall, it is because of a chain reaction, with one domino causing the fall of another. • Similarly, high levels of nutrients cause oxygen levels to become too low due to a serious of steps and interactions. • These steps can seem unrelated but can ultimately cause the destruction of an aquatic ecosystem.

19. Eutrophication • Step 1: The levels of nutrients become too high. • This could occur for a number of reasons but is most commonly caused by runoff. • For example, if fertilizer is spread on a field, rain water may carry soil and the fertilizer’s nutrients into a nearby body of water. • This will raise the levels of nitrogen and phosphorus. • These nutrients stimulate plant growth. • Excessive nutrient levels can come from a variety of sources including… • Over-fertilized fields • Poorly built feedlots • Over-fertilized yards and lawns • Overwhelmed sewage treatment plants

20. Eutrophication • Step 2: The nutrients from the fertilizer cause plants and algae to grow rapidly and excessively. • Fertilizers work in water just like they do in land. • Step 3: The rapid growth of algae enables a thick mat of algae to form on the surface of the water. • Light cannot penetrate this mat of algae. • Because there is no light, plants cannot photosynthesize under the water. • Because plants can’t photosynthesize, they can’t produce oxygen, and oxygen levels begin to drop.

21. Eutrophication • Step 4: Plants without light begin to die. Algae, with its short lifespan, also begins to die. • As these organisms die, they decompose. • The process of decomposition requires oxygen • As decomposition increases, oxygen levels continue to decrease. • With two factors reducing oxygen (low light and high decomposition), dissolved oxygen levels in the water begin to drop to dangerously low levels. • Step 5: Low levels of oxygen reduce many kinds of desirable organisms, including game fish and the macroinvertebrates(insects) they prey upon. • The balance of the food web is upset by the loss of these species.

22. Eutrophication • The aquatic ecosystem becomes less and less suitable for native species. • To make matters worse, the risk of invasive species (including carp and invasive species of cattails) increases as native species decrease. • The invasive species are often more competitive in low-oxygen conditions and out-compete the native species. • As plant matter accumulates (due to the explosive growth caused by high nutrient levels), these aquatic ecosystems become shallower over time. • This too reduces the ability of that habitat to sustain native species.

24. Definition of an aquatic ecosystem • Definition of a watershed • What is the base of the food chain in an aquatic ecosystem? • Difference between point and non-point source pollution? • What is the process of biomagnification and how does it work? • What is the process of eutrophication and how does it work? • What is a mutagenic pollutant? How do mutagens harm living organisms? • What is a PCB and why is it a problem? • Why should hunters and fishermen avoid lead-based products? • What are the causes of eutrophication and how do they cause this problem? • How does eutrophication lower oxygen levels?