Lecture 12/13

relatively high levels of dissolved salts

relatively pure, with few dissolved salts - short supply of drinkable freshwater - groundwater (20%) and surface freshwater (1%)

release of matter of energy into the environment that causes undesirable impacts on the health and well-being of humans or other organisms largely caused by human actions

discrete locations of pollution -e.g factory, industry, sewer pipes, shipping

pollution from multiple cumulative inputs over a large area - e.g cities, farms, mining, logging

the land area surrounding a body of water over which water such as rain can flow and potentially enter that body of water

• nutrient pollution • sediment • thermal pollution • oil pollution • plastic pollution • toxic chemicals

occurs when symbiotic algae leave coral

fertilizers, farms, sewage, lawns, golf courses

• phosphate-free detergents • planting vegetation to increase nutrient uptake • treat wastewater • reduce fertilizer application

Harmful algal blooms= nutrients increase populations of algae that produce toxins

clear-cutting, mining, poor cultivation practices

algal species produce reddish pigments that discolour water - causes illness/death to wildlife/humans - economic losses to fishing industries and beach tourism

• better management of farms and forests • avoid large-scale disturbance of vegetation

• dramatically changes aquatic habitats • fish may not survive

warmer water holds less oxygen - dissolved oxygen decreases as temperature increases - industrial cooling heats water - removing streamside cover also raises water temperature colder water also causes problems - water at bottom of reservoirs is colder - when water is released, downstream water temperatures drop suddenly and may kill aquatic organisms

modify industrial processes to reduce thermal shock

• Most oil pollution from small sources: boat leakage/runoff from land natural leaks from the seabed • Oil spills coat and poison wildlife

• Governments have implemented more stringent regulations • Oil spills have decreased with greater oil industry compliance

• Plastic is non-biodegradable • drifts for decades • washes up on beaches • wildlife eat it or get entangled • Marine debris affects people • equipment / property damage • negative aesthetic impacts

• arsenic, lead, mercury, acid rain, acid drainage from mines • pesticides, petroleum products, pharmaceuticals, synthetic organic chemicals

• poisoning animals and plants • altering aquatic ecosystems • affecting human health

• modify industrial processes • modify our purchasing decisions • legislating / enforcing stringent regulations of industry

• from coal combustion and other industrial sources (mining, paper) • Examples: Minimata Japan (1956) and Grassy Narrows First Nation Ontario (1970s) • bioaccumulates/ biomagnifies in food web • dangerous to young children, pregnant or nursing mothers – neurological effects • avoid eating swordfish, shark, albacore tuna • eat seafood low in mercury (catfish, salmon, canned light tuna)