1. Pollution • Materials with harmful impacts on the natural environment

2. Pollution Pathways

3. Point Sources

4. Non-point Source

5. Decay and Decomposition • Biodegradation • Radioactive Decay • Chemical reactions

6. Bioconcentration • Bioaccumulation • Contaminants are retained and concentrated in tissues of organisms • Biomagnification • Concentration of the contaminant increases up the food chain

7. Residence Time Average length of time a substance remains in a particular reservoir Inlet Stream Outlet Stream Lake Dissolution Precipitation Sedimentation

8. Sediment Pollution • Contamination of sediment by hazardous substances • Sediment itself acts as a pollutant • Siltation

9. Water Quality • Water quality depends on intended use • Standards vary with political jurisdiction • Standards reflect • immediate health risks • long term health risks • ascetic • analytical technology

10. Natural Influences • Common constituents of freshwaters • Ca, Na, K, Mg, Cl, SO4=,HCO3- • Composition of water depends on rock type • toxic elements can occur naturally • Flow rates can affect concentrations • higher concentrations at low flow

11. Types of Pollutants • Organic Matter (Oxygen-demanding waste) • Infectious Agents • Nutrients • Toxic Substances • Acidic and Caustic Effluents • Thermal Pollution • Suspended Solids

12. Organic Contaminants High Dissolved O2 Low Biochemical Oxygen Demand Stream Discharge Plume Sewage Plant

13. Eutrophication • High biological activity resulting from increased input of nutrients or organic matter with the ultimate development of a decreased volume of the lake • A natural stage in the life cycle of lakes • Can be accelerated by human activity cultural eutrophication

14. Toxic Substances • Chlorinated organic compounds • DDT, Dioxins, PCB • Heavy Metals • Cd, Pb, Sn, Hg • Hydrocarbons • benzene, PAH

15. Groundwater Pollution

16. leaks from storage tanks leaks from landfills seepage from septic systems accidental spills seepage from spray irrigation Leakage and seepage from mine spoils piles and tailings improper operation of injection wells infiltration of urban, industrial, and agricultural runoff Groundwater Pollution Sources

17. Advection Water Flow

18. Retardation • Retardation Factor • Retarded by • Dispersion • Sorption • Biodegradation

19. Dispersion

20. Sorption

21. Non-Aqueous Liquids Organic Liquid Water Water Organic Liquid Light Non- Aqueous Phase Liquid Dense Non- Aqueous Phase Liquid

22. LNAPL Oil Vadoze Zone Plume Saturated Zone Bedrock

23. DNAPL Trichloroethylene TCE Vadoze Zone Saturated Zone Plume Bedrock

24. Decontamination • Passive Remediation • Active Remediation • Extraction wells • Vapor extraction • Bioremediation -biostimulation • inject chemicals