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Topic 4.4: Water Pollution Starter: 1) List as many sources of water pollution as you can think off. 2) Suggest how we could reduce each of these. Types of Water Pollution Anthropogenic or natural Anthropogenic pollution thegreatimmensity.org Red Tide Caused by algae bloom Types of Water Pollution Point and Non “Point Types of Water Pollution Organic or Inorganic Human and animal waste Gulf of Mexico animalradio.com Types of Water Pollution Direct or Indirect Dumping toxins into waterways Excess nitrates entering waterways blogs.ntu.edu.sg Possible Sources of Water Pollution Sewage (human & animal) Pesticides Industry Pathogens Nitrates (fertilizers) Phosphates (detergents) Heavy metals (industry) Oil spills Heat (thermal pollution from electrical stations) Radioactive waste Solid domestic waste (trash debris) Suspended particles (from erosion) Invasive species Possible Effects of Water Pollution Eutrophication Loss of biodiversity (species & habitat) Increase in disease from pathogens Bioaccumulation and biomagnification Disruption of breeding grounds, nesting sites Damage to coral reefs Damage to organisms (ingesting plastics) Measuring Water Pollution Direct Method pH Nitrates or ammonia Dissolved oxygen Conductivity (may indicate dissolved pollutants or heavy metals) Turbidity Fecal coliform test Measuring Water Pollution Indirect Method Biochemical Oxygen Demand (BOD) Amount of dissolved oxygen required for decomposers to aerobically break down organic matter into a given volume of water Measuring Water Pollution Indirect Method Biochemical Oxygen Demand (BOD) If enough oxygen is present, aerobic decomposers will continue unit all waste is consumed Measuring Water Pollution Indirect Method Biodegradation of organic material utilizes oxygen. There is a finite source of oxygen, and once it is used the water becomes anoxic. This leads to anaerobic decomposition which leads to the formation of methane, hydrogen sulphide and ammonia (toxic). Measuring Water Pollution Indirect Method Biochemical Oxygen Demand (BOD) DO should be measured the initial amount of oxygen in the sample Sample should be sealed and in the dark After 5 days a second DO reading should be recorded Calculate the change in oxygen levels Unpolluted, natural water has a BOD less that 5mg/L Measuring Water Pollution Indicator Species Organisms that show something about their environment by their abundance or scarcity These species are sensitive to changes in an environmental factor Measuring Water Pollution Indicator Species In Freshwater Ecosystems the following are often indicators of the water quality Frogs and Toads have permeable skin so are affected by water pollutants Mayfly larva indicate clean water Water louse indicate polluted water Sludgeworms indicate very polluted water Measuring Water Pollution Image from biology portfolio Indicator species and biotic index • Indicator species indicate whether there is pollution present or not. • Biotic index is an indirect measure of pollution. • Assessing the relative abundance of different organisms. Measuring Water Pollution Biotic Indices (ex Trent Biotic Index) Indirect measure of pollution Often used in conjunction with BOD as invertebrates are sensitive to decreases in oxygen demand Often used to compare 2 ecosystems or point source pollutants using Simpson’s diversity index Measures the effect of pollutants on biodiversity Eutrophication Occurs when excess nutrients enter an aquatic ecosystem Drastic increase in algae growth May happen in freshwater or oceans (red tide) Natural or anthropogenic Human influence by using fertilizers or detergents Dead Zones Red tides Algal bloom Phytoplankton Red species Produce toxins that kill fish and accumulate in shell fish – can make humans seriously ill Dealing With Pollution Dealing with pollution Research methods aimed at mitigating the effects of eutrophication and place them in one of the above categories. Then evaluate 3 of your methods. E.g. Ban or limit detergents with phosphate (phosphate are only needed in hard water areas). This could be difficult as you would have to get companies to agree to making two products, and would people accept their washing powder being not as effective .
