I. Water Pollution – Sources and Effects

B. Sources2. Other factors

• Factors besides chemical pollutants can degrade water qualitya. Removal of adjacent vegetation

• Destabilization of shoreline• Removal of shade destabilizes temperatures

b. Siltation• Increased turbidity vision, photosynthesis• Burial of organisms, filling of water body

c. Alteration of drainage patterns• Damming, dredging, channelization• Changes in vegetation cover in watershed• Changes flow patterns, predictability, chemistry, sediment load

d. Leaching of chemicals from natural sources (geogenic, biogenic)• Salts, metals (Ex: As), nutrients (Ex: P), acids (Ex: tannins)

e. Warm weather• Raises temperatures, reduces oxygen solubility, may dry up

3. Interfere with designated beneficial usesI. Different beneficial uses for different water bodies different factors of

interest, different methods for remediation

II. Water Pollution – Components

A. 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 sensitive to O2 levels

• Low O2 levels also favor survival of anaerobic bacteria, many of which produce noxious gases (H2S, CH4)

• Examples1) Sewage (including animal and plant materials)2) Agricultural waste (leaves, plant debris, manure)3) 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

II. Water Pollution – Components

B. 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)1) Municipal sewage – Inadequately treated or spilled2) Stormwater drains3) Septic systems4) Runoff from livestock pens5) Sewage from recreational vehicles (boats, campers)

II. Water Pollution – Components

C. 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

Time Magazine - 1947

Beach on Long Island, NY - 1945

II. Water Pollution – Components

C. 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

II. Water Pollution – Components

C. 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

http://www.epa.gov/region9/superfund/pvshelf/images/ddtconcbig.gif

II. Water Pollution – Components

C. 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