ABSTRACT

Surface water and groundwater may become contaminated with hazardous compounds as a con sequence of natural and human activities. Pollutants of concern are both inorganic (heavy metals, radionuclides, nitrogen, phosphorous, etc.) and organic compounds (fuels, solvents, explosives, pesticides, herbicides, chemical and petrochemical compounds, etc.).1 Organic pollutants are mostly man-made and xenobiotic to organisms. They are released into the environment via spills, military activities, agriculture, industry, wood treatment, and so on. Inorganic pollutants occur as natural elements in the earth’s crust or atmosphere, and human activities such as mining, industry, traf c, agriculture, and military activities promote their release into the environment.2 Heavy metals and nutrients such as nitrogen and phosphorous are the inorganic pollutants of major concern worldwide.3-5

The release of heavy metals into the environment presents a serious threat. Over recent decades, the annual worldwide release of heavy metals reached 22,000 T for cadmium, 939,000 T for copper, 783,000 T for lead, and 1,350,000 T for zinc.3 Because of their high solubility in the aquatic environments, heavy metals can be absorbed by living organisms and enter the food chain.6 Exposure to high levels of these metals has been linked to cytotoxic, mutagenic, and carcinogenic effects on

human health and wildlife.7 As a consequence, their elimination from contaminated waters has become a major topic of research in recent years.8