Water Pollution Based on presentation from manskopf.com, Environmnaental Science Course Introduction to Environmental Health Eric Amster MD, MPH

Overview Identify common sources of water pollution. Discuss common routes of exposure and related health effects of aquatic toxins

Key Ideas What are major types and effects of water pollution? How do we measure water quality? Point versus Nonpoint sources What are the major sources of pollution?

What is water pollution? Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired usage.

What is water pollution? WHO: 3.4 million premature deaths each year from waterborne diseases 1.9 million from diarrhea U.S. 1.5 million illnesses

What is water pollution? Infectious Agents: bacteria and viruses often from animal wastes Oxygen Demanding Wastes: organic waste that needs oxygen often from animal waste, paper mills and food processing. Inorganic Chemicals: Acids and toxic chemicals often from runoff, industries and household cleaners

What is water pollution? Organic Chemicals: oil, gasoline, plastics, detergents often from surface runoff, industries and cleaners Plant Nutrients: water soluble nitrates, ammonia and phosphates often from sewage, agriculture and urban fertilizers Sediment: soils and silts from land erosion can disrupt photosynthesis, destroy spawning grounds, clog rivers and streams

Routes of Water Pollution Industrial effluent

Routes of Water Pollution Industrial effluent Urban runoff

Routes of Water Pollution Industrial effluent Urban runoff Groundwater contamination

Point and Nonpoint Sources NONPOINT SOURCES Urban streets Suburban development Wastewater treatment plant Rural homes Cropland Factory Animal feedlot POINT SOURCES Fig p. 494

How do we measure water quality Bacterial Counts: Fecal coliform counts from intestines of animals None per 100 ml for drinking >200 per 100 ml for swimming Sources: human sewage, animals, birds, raccoons, etc. See table 22-2 on page 493 for diseases transmitted by contaminated drinking water.

How do we measure water quality Dissolved Oxygen: BOD Biological Oxygen Demand…the amount of oxygen consumed by aquatic decomposers Chemical Analysis: looking for presence of inorganic or organic chemicals Suspended Sediment water clarity

Freshwater Stream Pollution Flowing streams can recover from moderate level of degradable water pollution if their flows are not reduced. Natural biodegradation process Does not work if overloaded or stream flow reduced Does not work against non biodegradable pollutants

Two Worlds Developed Countries Israel and other developed countries sharply reduced point sources even with population and economic growth Nonpoint still a problem Toxic chemicals still problem

Two Worlds Developing Countries: Serious and growing problem Half of world’s 500 major rivers heavily polluted Sewage treatment minimal $$$ Law enforcement difficult 10% of sewage in China treated Economic growth with little $$$ to clean up

Biomagnifications of PCBs in an aquatic food chain

Groundwater Why is groundwater pollution a serious problem? What is the extent of the problem? What are the solutions?

Groundwater Groundwater can become contaminated No way to cleanse itself Little dilution and dispersion Out of sight pollution Prime source for irrigation and drinking REMOVAL of pollutant difficult

Groundwater Pollution: Causes  Low flow rates  Few bacteria  Cold temperatures Coal strip mine runoff Pumping well Waste lagoon Accidental spills Groundwater flow Confined aquifer Discharge Leakage from faulty casing Hazardous waste injection well Pesticides Gasoline station Buried gasoline and solvent tank Sewer Cesspool septic tank De-icing road salt Unconfined freshwater aquifer Confined freshwater aquifer Water pumping well Landfill  Low oxygen Fig p. 502

Groundwater Pollution Prevention  Monitor aquifers  Leak detection systems  Strictly regulating hazardous waste disposal  Store hazardous materials above ground  Find less hazardous substitutes

Ocean Pollution Oceans can disperse and break down large quantities of degradable pollution if they are not overloaded. Pollution worst near heavily populated coastal zones Wetlands, estuaries, coral reefs, mangrove swamps 40% of world’s pop. Live within 62 miles of coast

Ocean Pollution Large amounts of untreated raw sewage (viruses) Leaking septic tanks Runoff Algae blooms from nutrients Dead zones NO DO Airborne toxins Oil spills

Drinking Water Quality  Maximum contaminant levels (MCLs)  Purification of urban drinking water  Bottled water  Protection from terrorism  Purification of rural drinking water

Purification of rural drinking water There can be simple ways to purify water: Exposing to heat and UV rays Fine cloths to filter water Add small amounts of chlorine