Chlorinated organic pollutants

Polychlorinated Dibenzo-p-dioxins (KDDs) and Dibenzofurans (PCDFs) 

PCDDs and PCDFs constitute a class of ubiquitous pollutants with aromatic structure, high chemical stability and extremely poor water solubility. They can occiu in the form of 75 PCDD congeners and 135 PCDF congeners (Table 1). At present, most PCDD and PCDF soinces are well characterized. These sources include chemical, thermal, photochemical and enzymatic reactions. Combustion processes, mainly incineration plants such as municipal solid waste incinerators, clinical waste incinerators and industrial waste incinerators are known to be some of the most important sources responsible for the presence of these contaminants in the environment. Soils and sedi- 

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As illustrated in Fig. 7. in micellar-enhanced iiltrafil-tration, surfactant is added to water at concentrations well above the CMC. Dissolved organic solutes (e.g., chlorinated organic pollutants) and multivalent ionic solutes... 

Scientists have also looked at the consequences of birds ingesting contaminated plastic. The results of these tests can be difficult to interpret because the birds natural prey can also contain hydrophobic contaminants. Three studies have examined the bioaccumulation of chlorinated organic pollutants in marine birds known to have ingested plastic. The earliest report dates back to 1988. In that study, multivariate analyses were used to assess... 

The methods, which allow in one procedure of analysis to overcome, for example, most pesticides which are used in agricultural practice in the present time, get development and introduction in practice. The contribution of the Ukrainian scientists in field of chromatographic analysis of Persistent Organic Pollutants (POPs, chlorinated hydrocarbons, PCB s) and supertoxicants, such as PCDDs, is estimated. 

An appreciation of the extent to which invertebrate species may be exposed to such chemicals comes from considering the effects of complex mixtures. In the North Atlantic ecosystem alone, hundreds of pollutant chemicals have been identified. These include metals, synthetic and chlorinated organics and polycyclic aromatic hydrocarbons. Over 300 aromatic hydrocarbons have been detected in some regions of the Chesapeake Bay, and high concentrations of PCBs have been... 

Sediment pollution. The concentrations of pollutants in the dated sediment cores have been determined in our laboratory by atomic absorption spectrophotometry (AAS). Donazzolo et al. (15) and Pavoni et al. (16) reported mainly heavy metal concentrations. Marcomini et al. (17) and Pavoni et al. (18) discussed the concentration profiles of organic pollutants such as chlorinated hydrocarbons and polycyclic aromatic hydrocarbons. 

Hydrocarbons. In other publications the historical trend of organic pollutant concentrations, namely polychlorinated biphenys (PCBs), chlorinated pesticides DDT and metabolites DDE, DDD, and polycyclic aromatic hydrocarbons (PAHs), have been reconstructed. For this purpose the sediments of the core sampled in the Lagoon area close to the industrial district were employed (16,17). 

There is a vast range of aqueous organic pollutants with a wide toxicity profile. Some, e.g. polychlorinated biphenyls, certain herbicides, fungicides and pesticides, and organo-mercury compounds, are persistent and may bioaccumulate in the food chain. Trace contaminants such as sodium chloride, iron and phenols (especially if chlorinated) may also impart a taste to water. Typical consent levels for industrial discharges are provided in Table 13.10. 

The pulp and paper industry is the largest industrial process water user in the U.S.5 In 2000, a typical pulp and paper mill used between 15,140 and 45,420 L (4000 to 12,000 gal) of water per ton of pulp produced. 1 2 3 4 General water pollution concerns for pulp and paper mills are effluent solids, biochemical oxygen demand (BOD), and color. Toxicity concerns historically occurred from the potential presence of chlorinated organic compounds such as dioxins, furans, and others (collectively referred to as adsorbable organic halides, or AOX) in wastewaters after the chlorination/ extraction sequence. With the substitution of chlorine dioxide for chlorine, discharges of the chlorinated compounds have decreased dramatically. 

HC1 is an acidic gas that forms when chlorinated organic compounds in hazardous wastes are burned. An incinerator burning hazardous waste cannot emit more than 1.8 kg of HCl/h or more than 1% of the total HC1 in the stack gas prior to entering any pollution control equipment, whichever is larger. 

The photocatalytic activity of ZnO nanomaterials for the degradation of some organic pollutants in water [173] (e.g., dyes [174]) was explored by several groups to achieve environmental benefits. Recent studies have indicated that ZnO can be used under acidic or alkaline conditions with the proper treatment [175,176]. ZnO nanomaterials were used as photocatalysts for the degradation of phenol [177] and chlorinated phenols such as 2,4,6-trichlorophenol [178]. ZnO nanomaterials were also used for the degradation of Methylene Blue [179], direct dyes [180], Acid Red [181], and Ethyl Violet [182],... 

Fig. 5. Relationship between the distribution (partition) coefficient on dimethyl dihydrogenated tallow montmorillonite for a range of non-ionic organic pollutants and their corresponding solubility in water. BHC is benzene hexachloride, the y-isomer of which is known as lindane aroclor 1232 and aroclor 1252 denote mixtures of polychlorinated biphenyls containing about 32 and 52% chlorine, respectively. After Beall (2003).

Kowalska M, Gtiler H, Cocke DL (1994) Interactions of clay minerals with organic pollutants. Sci Total Environ 141 223-240 Kukkadapu RK, Boyd SA (1995) Tetramethylphosphonium-smectite and tetramethylammonium-smectite as adsorbents of aromatic and chlorinated hydrocarbons - effect of water on adsorption efficiency. Clays Clay Miner 43 318-323... 

Grob et al. [220-223] have carried out very detailed and systematic studies of the closed-loop gas stripping procedure and applied it to the determination of xg/l of 1-chloroalkanes in water. Westerdorf [224] applied the technique to chlorinated organics, and aromatic and aliphatic hydrocarbons. Waggot and Reid [225] reported that a factor of major concern in adapting the technique to more polluted samples is the capacity of the carbon filter, which usually contains only 1.5-2 mg carbon. They showed that the absolute capacity of such a filter for a homologous series of 1-chloro-n-alkanes was 6 xg for complete recovery. 

Dioxin-like compounds are known to be one of the most harmful persistent organic pollutants of the chlorine based compounds. Dioxins are repeatedly synthesized and decomposed by complicated mechanisms and temperature changes at different locations in municipal solid waste incineration processes and the final streams discharged are commonly exhaust gas and incineration ash. Dioxins in different discharge types and compositions of effluents could be affected by incineration conditions such as temperature, feeding and discharging methods and incinerator type [47]. 

Galanopoulou S, Vgenopoulos A, Conispoliatis N (2005) DDTs and other chlorinated organic pesticides and polychlorinated biphenyls pollution in the surface sediments of Keratsini harbour, Saronikos gulf, Greece. Mar Pollut Bull 50(5) 520-525... 

The Ebro catchment is the largest river basin in Spain. It covers an area of 85,362 km2 (http //www.chebro.es) and receives the potential influence of three million people. It suffers a considerable ecological impact from different industrial activities located predominantly in the last third of its course. These activities result on the release to the Ebro River and to some of its tributaries of Tm quantities of chlorinated organic compounds, PBDE and other brominated flame retardants, mercury, and other metals. In addition, intensive agricultural practices, mainly concentrated in the last 30 km of the river course and in its Delta, imply the use of large quantity of pesticides and fertilizers. In this paper, we review physiological effects of these pollutants in resident fish and shellfish populations and provide a general picture of the health status of the low course of the Ebro River. 

Chlorinated organic compounds are notoriously persistent and are therefore prominent on the list of priority pollutants. However, this is not always the case,... 

Accelerated solvent extraction is a new technique for the extraction of a range of organic pollutants from soils and related material. The technique is based on the use of a solvent or combination of solvents to extract organic pollutants at elevated pressure and temperature from a solid matrix. The range of organic pollutants for which the technique is proposed includes semivolatile compounds, organochlorine pesticides, organophosphorus pesticides, chlorinated herbicides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons [53-56],... 

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