Presentation on theme: "Water Quality & Testing Water quality is the physical, chemical and biological characteristics of water The vast majority of surface water on the planet."— Presentation transcript:
Water Quality & Testing Water quality is the physical, chemical and biological characteristics of water The vast majority of surface water on the planet is neither potable (fit for drinking) nor toxic (poisonous) – essentially, not good or bad Approximately ___% of the world’s population has no access to potable water 25
Water Quality No single property can tell whether water is polluted or not Review: What are some sources of water pollution?
Sources of Water Pollution Industrial discharge of chemical wastes and byproducts Discharge of poorly-treated or untreated sewage Surface runoff containing pesticides or fertilizers Slash and burn farming practice, which is often an element within shifting cultivation agricultural systems Surface runoff containing spilled petroleum products Surface runoff from construction sites, farms, or paved and other impervious surfaces Discharge of contaminated and/or heated water used for industrial processes Acid rain caused by industrial discharge of sulfur dioxide (by burning high-sulfur fossil fuels) Eutrophication by runoff containing detergents or fertilizers Underground storage tank leakage, leading to soil contamination, and hence aquifer contamination Inappropriate disposal of various solid wastes and, on a localized scale, littering Oil spills
Water Regulations The The Environmental Protection Agency Agency (EPA) regulates limits on the amount of certain contaminants in the water The The Food and Drug Administration Administration (FDA) limits contaminants in bottled water Drinking Drinking water, including bottled water, water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of these contaminants does not necessarily indicate that the water poses a health risk.
Categories of Water Tests Biological Microorganisms such as fecal coliform bacteria (Escherichia coli), Cryptosporidium, and Giardia lamblia Dissolved organics: Colored Dissolved Organic Matter (CDOM), Dissolved Organic Carbon (DOC) Bethic Macroinvertebrates: Mollusca (Snails) Ephemeropteroidea (Mayfly) Plecoptera (Stonefly) Trichoptera (Caddisfly) Chemical Dissolved Oxygen(DO) pH Biochemical oxygen demand (BOD) Chemical oxygen demand (COD) Nutrients, such as nitrogen and phosphorus Dissolved metals and metalloids (lead, Mercury (element),arsenic, etc.) Pesticides Heavy Metals Pharmaceuticals Hormone analogs Physical Electrical Conductivity (salinity) Color, Taste and Odor Turbidity (clarity) Total suspended solids (TSS) Nutrients, such as nitrogen and phosphorus Dissolved salts and elements (sodium, chloride, potassium, calcium, manganese, magnesium) Temperature
Temperature Determine types of organisms that can live in water Affects how much oxygen water can hold –Warm water holds less oxygen Thermal Pollution (increased water temperature) –decreasing oxygen supply –killing fish juveniles which are vulnerable to small increases in temperature –affecting ecosystem composition.
Dissolved Oxygen Measure of the amount of oxygen dissolved in water Measurement for outdoor bodies of water –More DO generally relates to “healthier” water (oxygen necessary for most aquatic species to breath) Related to Biochemical Oxygen Demand (BOD) –how fast biological organisms use up oxygen in a body of water
pH Potential of Hydrogen – measures hydrogen concentration in water 7.0 is neutral on scale of 0 – 14 Can affect how chemicals dissolve in water Representative pH values SubstancepH Hydrochloric Acid, 10M Lead-acid battery 0.5 Gastric acid 1.5 – 2.0 Lemon juice 2.4 Cola2.5 Vinegar2.9 Orange or apple juice 3.5 Tomato Juice 4.0 Beer4.5 Acid Rain <5.0 Coffee5.0 Tea or healthy skin 5.5 Urine6.0 Milk6.5 Pure Water 7.0 Healthy human saliva 6.5 – 7.4 Blood 7.34 – 7.45 Seawater 7.7 – 8.3 Hand soap 9.0 – 10.0 Household ammonia 11.5 Bleach12.5 Household lye 13.5
Nutrients Eutrophication, strictly speaking, means an increase in chemical nutrients (typically nitrogen and phosphorus) Resultant increase in primary productivity –excessive plant growth and decay Further impacts, including lack of oxygen and severe reductions in water quality and in fish and other animal populations.
Turbidity / Total Suspended Solids Amount of particulate matter in water Related to sediment, phytoplankton and nutrients in water Turbidity reflects matter visible to naked eye (measured with secchi disk) TSS collects dissolved material (filtered) measured as weight
Salinity Dissolved salt content in water Influences organisms that can live in that area Oceans are about 35 ppt or so Water salinity Fresh water Brackish water Saline water Brine < 0.05 % 0.05 - 3 % 3 - 5 % > 5 % < 500 ppm 500 - 30 000 ppm 30 000 - 50 000 ppm > 50 000 ppm
Heavy Metals Living organisms require trace amounts of some heavy metals, including iron, cobalt, copper, manganese, molybdenum, vanadium, strontium, and zinc – excessive levels can be detrimental to the organism. Other heavy metals such as mercury, lead and cadmium are toxic metals –they have no known vital or beneficial effect on organisms –their accumulation over time in the bodies of mammals can cause serious illness
Microorganisms E. coli (fecal coliform bacteria) can generally cause several intestinal and extra-intestinal infections Cryptosporidium is a protozoan pathogen and causes a diarrheal illness called cryptosporidiosis Giardia lamblia is a flagellated protozoan parasite that colonises and reproduces in the small intestine, causing giardiasis. Symptoms of include diarrhea, malaise, excessive gas, etc giardiasis