Toxaphene bioaccumulation

Toxaphene is a very stable, persistent, solid compound that requires decades to break down into different components. In fact, nearly 45% of the toxaphene applied to the soil in 1951 was detected 20 years later. Toxaphene has very low solubility in water, but in organic solvents, it is miscible. Toxaphene is very volatile and quickly changes to vapor, which transmigrates in the atmosphere to very long distances. Reports indicate that toxaphene bioaccumulates, rapidly breaks down in the intact body of animals, and eventually discharges out.68... 

Chlorinated micropoUutants are harmful for man and environment due to their toxicity, persistence, and bioaccumulation. Persistent compounds are very stable and difficult to get metabolized and mineralized by biological and chemical processes in the environment, and as a result, they have become ubiquitous in water, sediments, and the atmosphere bioaccumulation is the result of the lipophilicity of these compounds. Polychlorinated dibenzodioxins and -furans (PCDD/F) are not produced purposely like many of other chlorinated technical products, such as chlorinated biocides DDT, lindane, and toxaphene. The production and use of persistent organic pollutants (POPs), the dirty dozen has now been banned worldwide by the Stockholm protocol. It should be mentioned that about 3000 halogenated products have now been isolated as natural products in plants, microorganisms, and animals," but the total amount of these products is much smaller compared to xenobiotics. 

Lindane (gamma-hexachlorocyclohexane) is one of the last of the old style organochlorine pesticides still in use. Use of organochlorines such as DDT, aldrin, dieldrin, heptachlor, and toxaphene is restricted or banned in many countries because of their persistence in the environment, bioaccumulation, and toxicity. Lindane was first isolated in 1825 along with other similar compounds, but its deadly effects on insects were not recognized until the 1940s. 

Toxaphene Pesticide - organochlorine - bioaccumulates - extensively used on US cotton crops from 1 947 to 1 980 Manufacture and use prohibited in the US... 

The Binational Toxics Strategy between the USA and Canada has identified 12 bioaccumulative substances (referred to as Level-1 substances) having significant persistency and toxicity to the Great Lakes system, with the goal of reducing the sources of these substances to achieve naturally occurring levels [23]. Six of the 12 Level-1 substances are OC pesticides aldrin/dieldrin, chlordane, DDT, HCB, mirex, and toxaphene. Several other OC pesticides, such as endrin, heptachlor/heptachlor epoxide, hexachloro-cyclohexanes, tetra- and penta-chlorobenzenes, and pentachlorophenol, have been identified as Level-2 substances. 

Keywords Toxaphene Chlorobornanes Persistence Deposition Bioaccumulation... 

Log bioaccumulation factor = concentration in lake trout (lipid weight) concentration in water. Toxaphene water concentrations from Swackhamer et al. [65] except for Muir et al. [74], PCB water concentrations from Pearson et al. [146] for Lake Michigan and Swackhamer [141] for Lake Superior... 

Fig. 14 Bioaccumulation factor (BAF) in Lake Superior lake trout versus octanol-water partition coefficient (.Kow) for 19 toxaphene congeners plus B9-715 and B10-1010 [74], Results for 6 congeners (P31, B8-1413, B9-1679, B9-1046, B9-715 and B10-1010) were estimated assuming water concentrations at the detection limit. The coefficient of variation r2 = 0.35 P< 0.01...

Fisk, A T., Bosenberg, B., Cymbalisty, C.D, Stem, G.A., Muir, D.C.G. (1999) Octanol/water partition coefficients of toxaphene congeners determined by the slow-stirring method. Chemosphere 39, 2549-2562 Fisk, AT., Norstrom, R.J., Cymbalisty, C.D, Muir, D.C.G. (1998) Dietary accumulation and depuration of hydrophobic oiganochlo-rines bioaccumulation parameters and their relationship with the octanol/water partition coefficient. Environ. Toxicol. Chem. 17, 951-961. 

The question about the fate of toxaphene in the environment cannot be answered in a simple way. In the environment, only some toxaphene components remain unmetabolized and are accumulated in biota. This leads to a simpler toxaphene residue pattern compared to the technical mixture. In 1979, Saleh et al. studied the metabolism of B7-515 (P-32) and technical toxaphene with seven test animals. Both were metabolized the least in chicken and the most in monkeys [175]. Furthermore, the major toxaphene congeners present in the technical mixture are not the same as those found in environmental samples due to selective bioaccumulation/metabolization and abiotic degradation mechanisms (see Table 6). 

In general, only highly hydrophobic compounds have a potential to bioaccumulate [225]. Based on fugacity modelling, components with log Kow < 6 are not expected to bioaccumulate [226]. Using food chain models, Suedel et al. claimed that compounds with log Kow > 4.0 may have a potential to bioaccumulate in aquatic food webs [227]. One study estimated log Kow of technical toxaphene as 6.44 [3], while another study found a value < 5 [227]. Therefore, a categorization of toxaphene in terms of bioaccumulation is difficult. 

The fragment constant method [228] allowed the calculation for B7-1001, B8-1413 (P-26), and B9-1679 (P-50) of log Kow values of 6.2, 6.5, and 6.6, respectively [229]. Geyer et al. [230] estimated log Kow and bioconcentration factors (BCFs) for seven persistent toxaphene components. The log Kow ranged from 5.8 to 7.9, those for B8-1413 (P-26) and B9-1679 (P-50) were similar to those reported by Fisk et al. [229]. Log Kow values of individual toxaphene components which exceed the average log Kow of 6.44 for technical toxaphene should be particularly considered as candidates for bioaccumulation. 

In the last three decades, there has been considerable public concern about the presence of halogenated anthropogenic compounds in the environment because of their persistence, the bioaccumulation potential, and the health risks that they bring about [13]. Examples of members of this family of xenobiotics are polychlorinated biphenyls (PCBs), polychlorinated terphenyls (PCTs) and toxaphene. Polychlorinated biphenyls were described as ubiquitous, environmentally harmful substances more than 30 years ago [4j. In addition, the presence of PCBs and toxaphene in the environment has been extensively documented [5-7]. In contrast, litde attention has been paid to polychlorinated terphenyls, which are similar to PCBs in chemical characteristics and applications. In this chapter, we discuss different methods described in the literature for the analysis of PCTs and toxaphene using high resolution gas chromatography (HRGC) coupled to mass spectrometry (MS). 

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