Water Pollution – Sources and Effects Sources Pollution Point sources Discharge directly into receiving waters Easier t

1. Water Pollution – Sources and Effects • Sources • Pollution • Point sources • Discharge directly into receiving waters • Easier to characterize and regulate than NPS’s • Non-point sources • Pollutants from diffuse sources • May vary regionally and seasonally • Ex – Chloride from salting streets in winter • Challenging to regulate (TMDL) • Pollutants • Priority (120) & Non-priority (47) – EPA • Standards • Criteria maximum concentrations • Criterion continuous concentration

2. Water Pollution – Sources and Effects • Sources • Other factors • Factors besides anthropogenic chemical pollutants can degrade water quality • Removal of adjacent vegetation • Destabilization of shoreline • Removal of shade destabilizes temperatures • Siltation • Increased turbidity  reduced vision, photosynthesis • Burial of organisms, filling of water body • Alteration of drainage patterns • Damming, dredging, channelization • Changes flow speed, volume, predictability • Deforestation within the watershed • Affects chemistry, flow patterns, sediment load • Leaching of chemicals from natural deposits • Salts, nutrients, metals • Warm weather • Raises temperatures, reduces oxygen solubility, may dry up • Natural organic chemicals • Tannic acids from decaying leaves  brown water, low pH • Interfere with designated beneficial uses • Different beneficial uses for different water bodies  different factors of interest, different methods for remediation

3. Water Pollution – Components • Oxygen-Depleting Substances • Pollutants may lower O2 concentrations directly or indirectly • Usually biodegradable (organic wastes) • Reduced O2 levels can influence species composition in a water body • Ex – salmon and trout are sensitive to O2 levels • Low O2 levels also favor survival of anaerobic bacteria, many of which produce noxious gases (H2S, CH4) • Examples • Sewage (including animal and plant materials) • Agricultural waste (leaves, plant debris) • Manure • Food processing wastes • Toxic wastes can kill aquatic organisms, leading to O2 depletion by decomposing bacteria • Warm temperatures exacerbate O2 depletion • Reduce solubility of oxygen • Accelerate bacterial decomposition rates

4. Water Pollution – Components • Infectious Agents • Pathogenic bacteria • Common components of animal wastes • Can produce outbreaks of typhoid, cholera, salmonellosis, infectious hepatitis, dysentery (affect billions of people) • Examples • Giardia causes swimmer’s itch by irritating skin but can cause intestinal problems internally • Cryptosporidium contaminated Milwaukee water supply in 1993 • More than 400,000 people with symptoms and 100+ deaths • Cysts passed through filtration in water treatment system and went undetected • Very difficult to scan water bodies for all potential pathogens (problem: lag time b/w test & results) • Use of indicator organisms (coliform bacteria, enterococci) • Possible sources (source identification challenging) • Municipal sewage – Inadequately treated or spilled • Stormwater drains • Septic systems • Runoff from livestock pens • Sewage from recreational vehicles (boats, campers)

5. Water Pollution – Components • Toxic Organic Chemicals (TOCs) • Usually synthetic chemicals • Persistent organic pollutants (POPs) • Polychlorinated biphenyls (PCBs) • Polycyclic aromatic hydrocarbons (PAHs) • Dioxins • Herbicides, pesticides (Ex: chlordane, DDT) • Characteristics • Bioavailable – readily assimilated • Lipid soluble – incorporated into lipid deposits • Bioaccumulate – concentrations increase with time and exposure • Biomagnify – concentrations increase through food web • Tend to be resistant to degradation • Facilitates wide dispersal • Long residence times (persistence) • Ex – DDT near White Point • Effects – Poorly understood for most compounds • CNS damage • Liver damage • Birth defects

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8. Water Pollution – Components • Toxic Organic Chemicals (TOCs) • Usually synthetic chemicals • Persistent organic pollutants (POPs) • Polychlorinated biphenyls (PCBs) • Polycyclic aromatic hydrocarbons (PAHs) • Dioxins • Herbicides, pesticides (Ex: chlordane, DDT) • Characteristics • Bioavailable – readily assimilated • Lipid soluble – incorporated into lipid deposits • Bioaccumulate – concentrations increase with time and exposure • Biomagnify – concentrations increase through food web • Tend to be resistant to degradation • Facilitates wide dispersal • Long residence times (persistence) • Ex – DDT near White Point • Effects – Poorly understood for most compounds • CNS damage • Liver damage • Birth defects

10. Water Pollution – Components • Toxic Organic Chemicals (TOCs) • Usually synthetic chemicals • Persistent organic pollutants (POPs) • Polychlorinated biphenyls (PCBs) • Polycyclic aromatic hydrocarbons (PAHs) • Dioxins • Herbicides, pesticides (Ex: chlordane, DDT) • Characteristics • Bioavailable – readily assimilated • Lipid soluble – incorporated into lipid deposits • Bioaccumulate – concentrations increase with time and exposure • Biomagnify – concentrations increase through food web • Tend to be resistant to degradation • Facilitates wide dispersal • Long residence times (persistence) • Ex – DDT near White Point • Effects – Poorly understood for most compounds • CNS damage • Liver damage • Birth defects

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13. Water Pollution – Components • Toxic Organic Chemicals (TOCs) • Usually synthetic chemicals • Persistent organic pollutants (POPs) • Polychlorinated biphenyls (PCBs) • Polycyclic aromatic hydrocarbons (PAHs) • Dioxins • Herbicides, pesticides (Ex: chlordane, DDT) • Characteristics • Bioavailable – readily assimilated • Lipid soluble – incorporated into lipid deposits • Bioaccumulate – concentrations increase with time and exposure • Biomagnify – concentrations increase through food web • Tend to be resistant to degradation • Facilitates wide dispersal • Long residence times (persistence) • Ex – DDT near White Point • Effects – Poorly understood for most compounds • CNS damage • Liver damage • Birth defects

14. Water Pollution – Components • Other Chemicals and Minerals • Acids and acidifying compounds • Many originate in the atmosphere (sulfuric acid, nitric acid) or from runoff passing through mine tailings • Aquatic organisms generally intolerant of low pH • Effects • Irritates gills of fishes and crustaceans and interferes with gas exchange • Irritates slime layer of fishes (reduces resistance to pathogens) • Erodes shells of aquatic mollusks and arthropods • Impedes ability of crustaceans to recalcify after molting • Facilitates release of toxins bound to particles in sediments

16. Water Pollution – Components • Other Chemicals and Minerals • Acids and acidifying compounds • Many originate in the atmosphere (sulfuric acid, nitric acid) or from runoff passing through mine tailings • Aquatic organisms generally intolerant of low pH • Effects • Irritates gills of fishes and crustaceans and interferes with gas exchange • Irritates slime layer of fishes (reduces resistance to pathogens) • Erodes shells of aquatic mollusks and arthropods • Impedes ability of crustaceans to recalcify after molting • Facilitates release of toxins bound to particles in sediments

17. Water Pollution – Components • Other Chemicals and Minerals • Nutrients • Nitrates, nitrites, phosphates • Common sources • Crop and lawn fertilizers • Manure • Sewage • Detergents containing phosphates and nitrates • Excessive nutrient loading  eutrophication • Effects • Plant growth can clog waterways (ecology, navigation) • Plants can interfere with recreation (swimming, boating) • Algal growth can impede submerged plant growth • Nighttime oxygen depletion • Nitrate  methemoglobinemia (blue baby syndrome) • Nutrients can be difficult to control once in a system • Recycling and regeneration • Eutrophied water bodies can recover if sources are removed • Ex – Lake Washington