Pentachlorophenol in fish

Kobayashi, K. 1978. Metabolism of pentachlorophenol in fishes. Pages 89-105 in K.R. Rao (ed.). Pentachlorophenol Chemistry, Pharmacology, and Environmental Toxicology. Plenum Press, New York. 

Larsson, P., G. Bremle, and L. Okla. 1993. Uptake of pentachlorophenol in fish of acidified and nonacidified lakes. Bull. Environ. Contam. Toxicol. 50 653-658. 

Kobayashi, H. Metabolism of pentachlorophenol in fish, in Pesticide andXenobiotic Metabolism in Aquatic Organisms, ACS Symposium Series 99 (Washington, DC American Chemical Society, 1979). 

Figure 8.4. Metabolic pathways for pentachlorophenol in fish. (From Kobayashi, 1978.)...

TCP), and pentachlorophenol (PCP), in order of abundance. Minor amounts of other trichlorophenols and dichlorophenols may also be present, as well as recalcitrant polychlorinated phenoxyphenols (PCPPs) and PCDD/Fs as impurities [75, 76]. In Finland, approximately 30,000 tons of CP products were used between 1934 and 1988, when they were banned because of their potential toxicity to humans and the environment [77, 78]. The careless manufacturing and application of wood preservatives together with the lack of suitable waste disposal caused massive contamination of river sediments and sawmill sites. For example, the river Kymijoki in southern Finland was identified as the largest source of dioxins accumulating in fish in the entire Baltic area. Similar products were used in other European countries, especially Nordic countries with a large forestry industry, such as Sweden [79]. 

McKim, J.M., P.K. Schmieder, R.W. Carlson, and E.P. Hunt. 1987. Use of respiratory-cardiovascular responses of rainbow trout (Salmo gairdneri) in identifying acute toxicity syndromes in fish. 1. Pentachlorophenol, 2,4-dinitrophenol, tricaine methanesulfonate and 1-octanol. Environ. Toxicol. Chem. 6 295-312. 

Stehly, G.R. and W.L. Hayton. 1988. Detection of pentachlorophenol and its glucuronide and sulfate conjugates in fish bile and exposure water. Jour. Environ. Sci. Health B23 355-366. 

Figure 8. The bioconcentration ratios of chlorophenols in goldfish at 1 h exposure to their media as a function of the difference between pH and pKa. 4-CP 4-chlorophenol, 2,5-DCP 2,5-dichlorophenol, 3,5-DCP 3,5-dichlorophenol, 2,4,6-TCP 2,4,6-trichlorophenol, PCP pentachlorophenol, 2-CP 2-chlorophenol, 3-CP 3-chlorophenol, 2,4-DCP 2,4-dichlorophenol, 2,3-DCP 2,3-dichlorophenol, 2,4,5-TCP 2,4,5-trichlorophenol, 2,3,4,6-TCP 2,3,4,6-tetrachlorophenol, 2,6-DCP 2,6-dichlorophenol. Reprinted from [185] Water Res., 29, Kishino, T. and Kobayashi, K. Relation between toxicity and accumulation of chlorophenols at various pH, and their absorption mechanism in fish , pp. 431-442. Copyright (1995), with permission from Elsevier...

However, PCP is the second heaviest used pesticide in the United States, although it has been mostly used for the purpose of wood preservation(1). Under such circumstances, an international symposium on "Pentachlorophenol" convened by K. Ranga Rao(University of West Florida) was held in Pensacola, Florida, June 27-29, 1977, concerning the chemistry, pharmacology, and environmental toxicology of PCP. At the symposium, I presented a paper(2) on the metabolism of PCP in fishes, mostly reviewing the works on the absorption, excretion and detoxification of PCP in fish and shellfish, which were done in our laboratory. 

The presence of high levels of pentachlorophenol in mammalian blood is well-known. The fact that as many as 120 or more phenolic OHS are present in both human and fish (salmon) blood demonstrates, in addition to lipid rich tissues, the potential importance of blood for the accumulation of environmental contaminants or their metabolites. Phenolic OHS are not strongly accumulated... 

Marked differences in the effect of temperature on the toxicity of pentachlorophenol to rainbow trout have been observed (Hodson and Blunt 1981), and early life-cycle stages were more adversely affected in fish exposed to a cold-water regime (6°C) than with those exposed to a warm-water regime (10°C). These results could have serious implications for natural populations exposed to pentachlorophenol during low temperatures when spring egg development occurs. 

McKim and associates (1986) have conducted aquatic toxicokinetic studies using " C-labeled pentachlorophenol in rainbow trouts. At sublethal doses and over its 65-hour half-life period, about 50% was eliminated over the gills, 30% in the feces and bile, and 20% in the urine. It was found that pentachlorophenol and its metabolites were rapidly eliminated from the bodies of fish. 

FISH is also suitable for revealing the spatial distribution of certain populations. For example, the Desulfitobacterium frappieri PCP-1 used for the anaerobic degradation of pentachlorophenol in an anaerobic upflow sludge bed (UASB) system was found to densely colonize the outer biofilm layer as revealed by FISH [124]. 

Levels of pentachlorophenol in the soil decrease through biodegradation and in the air, by photodegradation. PCP has a high adsorption coefficient 3000 to 4000) and it is therefore strongly adsorbed to the soil particles and sediments. It will also bioconcentrate to a small extent in fish and animals. It is also known to volatilize from water surfaces and soil. The environmental fate of pentachlorphenol is shown in Fig. 38.6. 

Kobayashi, K., S. Kimura, and E. Shimizu. 1977. Studies on the Metabolism of Chlorophenols in Fish—IX. Isolation and Identification of Pentachlorophenols- -glucuronide Accumulated in Bile of Goldfish, Bulletin of Japanese Society of Scientific Fisheries, vol. 43, pp. 601-607. 

Kobayashi, K., Kimura, S. and Shimizu, E. 1977. Studies on the metabolism of chlorophenols in fish - IX. Isolation and identification of pentachlorophenol-/3-glucuronide accumulated in bile of goldfish. Bull. Jap. Soc. Sci. Fish. 43 601-607. 

The decomposition of benzene and naphthalene and its homologues by microorganisms has already been discussed earlier. The metabolizing mechanisms of naphthalenes in fish have been well studied [47, 49]. Decomposition products of chlorobenzene in daphnia, mosquitos, snails and fishes are the polar compounds chlorophenol and chloro-o-dihydroxybenzene amongst other compounds, those of nitrobenzene aniline, acetanilide, aminophenols and nitrophenols and those of hexachlorobenzene pentachlorophenol and unknown compounds [71]. Bromoben-zene is deactivated to the toxic bromophenol [217]. In the case of man and land mammals, studies have concentrated on the metabolism of benzene, toluene, xylenes and styrene, which are also significant in occupational medicine [12, 13, 136, 195, 196, 215-217], A comparison of the metabolism of benzene into phenol in various animal species with the aid of microsomal preparations of the lungs or liver yielded vast differences. However, it is possible for benzene, in part, to inhibit or prevent its own metabolism [218]. 

The Level I calculations for environmental pHs of 5.1 and 7 suggest that if 100,000 kg (100 tonnes) of pentachlorophenol (PCP) are introduced into the 100,000 km2 environment, most PCP will tend to be associated with soil. This is especially the case at low pH when the protonated form dominates. Very little partitions into air and only about 1% partitions into water. Soil contains most of the PCP. Sediments contain about 2%. There is evidence of bioconcentration with a rather high fish concentration. Note that only four media (air, water, soil and bottom sediment) are depicted in the pie chart therefore, the sum of the percent distribution figures is slightly less than 100%. The air-water partition coefficient is very low. As pH increases, dissociation increases and there is a tendency for partitioning to water to become more important. Essentially, the capacity of water for the chemical increases. Partitioning to air is always negligible. 

Pentachlorophenol was found at high concentrations in all samples of sediments, waters, and biota collected near industrial facilities that used PCP as a wood preservative (Niimi and Cho 1983 Oikari and Kukkonen 1988) (Table 23.3). Fish can bioconcentrate PCP from water up to 10,000 times (Fox and Joshi 1984). However, similar concentrations were measured in blue mussel, Mytilus edulis (Folke and Birklund 1986), and softshell clam, Mya arenaria (Butte et al. 1985), from the vicinity of PCP-contaminated wastewater discharges as well as from more distant collection sites. Thus, PCP bioaccumulation in marine bivalve molluscs does not appear to be dose related. 

Pentachlorophenol was most toxic and most rapidly metabolized in aquatic environments at elevated temperatures and reduced pH. Adverse effects on growth, survival, and reproduction of representative sensitive species of aquatic organisms occurred at PCP concentrations of about 8 to 80 pg/L for algae and macrophytes, about 3 to 100 pg/L for invertebrates (especially molluscs), and <1 to 68 pg/L for fishes, especially salmonids. Fatal PCP doses for birds were 380 to 504 mg/kg BW (acute oral), >3850 mg/kg in diets, and >285 mg/kg in nesting materials. Adverse sublethal effects were noted at dietary levels as low as 1.0 mg/kg ration. Residues (mg/kg fresh weight) in birds found dead from PCP poisoning were >11 in brain, >20 in kidney, >46 in liver, and 50 to 100 in egg. 

Anderson, R.S. and L.L. Brabacher. 1992. In vitro inhibition of medaka phagocyte chemiluminescence by pentachlorophenol. Fish Shellfish Immunol. 2 299-310. 

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