An Overview of the Persistent Organic Pollutants in the Freshwater System

Ecological Water Quality -Water Treatment and Reuse 456 about the organic contaminants in the freshwater system.After introducing the issue of fresh water pollution in the second section, we shall intensely focus on different aspects of contamination of fresh water by persistent organic compounds in section three.In this section, we shall describe the categories of organic compounds which contribute to fresh water contamination with their sources, fate and effects.This section will also include a review of detection techniques available for the detection of organic contaminants in the freshwater system.The section will be concluded with two sub sections -one highlighting our understanding of the natural assimilation of persistent organic contaminants through normal aquatic ecological processes and the other focusing on the techniques that we have at our discretion for the removal of such contaminants from water in order to purify water.Different conventions and protocols are in place to reduce and control the issue of organic contamination of water.Before concluding the chapter, we shall try to shed some light on the current status of such protocols and conventions regarding organic contamination of fresh water. Pollution and contamination of fresh waterContamination of fresh water is a natural process; in the passage of the normal cycling of water through the water cycle, during precipitation, different organic substances of varied origins, both soluble and insoluble, get transported into fresh water streams.Among the natural contributors of organic contaminants, volcanic eruption, forest fires, natural decomposition of organisms, are substantial sources [4].Organic substances of biological origin also result from either excreta or wastes from of living organisms, from municipal waste decomposition, etc.Among the dissolved organic substances in water, humic and fulvic substances, polycyclic aromatic hydrocarbons (PAHs), halogenated aromatic and aliphatic hydrocarbons, phthalate esters are the major classes [12].However, the input of organic contaminants from natural sources does not increase the way they are increasing from anthropogenic sources.Human activities are increasing the consumption of the already known organic compounds all over the world for meeting diverse needs while organic pharmaceuticals, pesticides, paints and coloring materials, cosmetics, etc with novel properties are synthesized every day for many purposes.Consequently, the quantity and diversity of anthropogenic organic contaminants that enter the fresh water system and polluting it are accumulating.According to a recent study [6] on the presence organic contaminants in untreated drinking water sources in USA, for surface sources, natural sterol -cholesterol, herbicide -metolachlor, nicotine metabolite -cotinine, natural plant sterol -βsitosterol and caffeine metabolite -1,7-dimethylxanthine were the five most frequently detected organic contaminants.In ground water sources, solvent -tetrachloroethylene, pharmaceutical -carbamazepine, plasticizer -bisphenol-A, caffeine metabolite -1,7dimethylxanthine, and fire retardant -tri (2-chloroethyl) phosphate were the five respective major contaminants.However, they could not establish any specific seasonal trends in the distribution patterns of contaminants. Organic contaminants in freshwater systemIn recent decades there has been escalating concern about the potential effects of the occurrence of a diverse array of organic contaminants in the fresh water system on the www.intechopen.com