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Effects of a chromated-copper-arsenate wood preservative on the bacterial degradation of pentachlorophenol.

The effect of a chromated-copper-arsenate wood preservative on the degradation of pentachlorophenol by Flavobacterium sp. strain ATCC 53874 was examined in liquid culture. Both a commercially available and a laboratory-prepared formulation were tested. Each increased the lag time required for measurable pentachlorophenol degradation and the time required for complete degradation to nondetectable levels. This response was noted at all pentachlorophenol concentrations examined (10, 25, 50, 75, and 100 micrograms.mL-1). The commercial formulation of chromated-copper-arsenate had the more significant impact on pentachlorophenol degradation. Inhibitory effects were evident at chromated-copper-arsenate component metal concentrations 0.1-0.5 mg.L-1. These levels are thousands of times below those used commercially.

Arsenates↗

Reproductive efficiency in mink (Mustela vison) treated with the pesticides lindane, carbofuran and pentachlorophenol.

Mink are carnivores of agroforestry fringe habitats and are exposed to pesticides that biomagnify within the food chain. Some pesticides are thought to disrupt reproductive and endocrine functions. In Expt 1, four groups of mink (n = 10) were fed either a control diet, or diets treated with lindane (1 mg kg-1 day-1), carbofuran (0.05 mg kg-1 day-1) or pentachlorophenol (1 mg kg-1 day-1) from before breeding until weaning. Mink were mated twice, at 7-8 day intervals. The treatments had no effect on the proportion of mink accepting the first mating; however, lindane and pentachlorophenol caused a decrease in the percentage of females accepting the second mating. Lindane and pentachlorophenol caused a decrease in whelping rate, although litter size was not affected. Carbofuran had no effect on fertility. Mink that mated only once had a lower whelping rate than mink that mated twice; therefore, it could not be determined whether the decreased whelping rates were due to the lack of a second mating or to increased embryo loss. In Expt 2, two groups of mink (n = 15) were fed a control diet or a diet treated with lindane (1 mg kg-1 day-1) from before mating until weaning. Mink were mated twice on two consecutive days. Lindane did not affect mating response at either mating. Whelping rate, but not implantation rate, was decreased by the lindane treatment. The proportion of embryos lost after implantation (implantation scars not represented by kits at whelping) was increased by the lindane treatment. In conclusion, both lindane and pentachlorophenol decreased fertility in mink, and the lindane effect was primarily a result of embryo mortality after implantation.

Animals↗

[Detection of pentachlorophenol in biomaterial using HPLC].

OBJECTIVE: To develop a method of detecting pentachlorophenol in biomaterial. METHODS: The samples were extracted by ether, and the characters of the high performance liquid chromatography (HPLC) method were studied. RESULTS: A method for the detection of pentachlorophenol in fish tissue samples was set up with the conditions of chromatography as follows: the compounds are separated on Hypersil ODS column(4.6 mm i.d. x 150 mm, 5 microns) and eluted with methanol which contains 2 g/L NH4Ac (20:80) using 305 nm as the detecting wavelength, the recovery of method being 76%, the linear range 0.042 microgram/g-1.344 micrograms/g, and the correlation coefficient 0.9994, the limit of quantification 0.014 microgram/g. Finally, pentachlorophenol was successfully detected in the fish tissue samples. CONCLUSION: The method has been proven useful in the forensic cases involved in the poisoning of pentachlorophenol.

Animals↗

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the in vivo and in vitro dechlorination of pentachlorophenol.

The metabolism of pentachlorophenol has been studied in the rat after pretreatments with phenobarbital, 3-methyl cholanthrene or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In addition to the previously identified metabolite, tetrachloro-p-hydroquinone, trichloro-p-hydroquinone has been identified in urine as a metabolite. The formation of the latter represents a type dechlorination different from that of the formation of tetrachlorohydroquinone. The inducing agents, 3-methylcholanthrene and TCDD have similar effects on the dechlorination and increase the formation of tetrachloro-p-hydroquinone more pronounced than does phenobarbital. In contrast to phenobarbital they also increase the formation of trichloro-p-hydroquinone and the total elimination of pentachlorophenol and its metabolites. The in vivo findings are supported by in vitro studies with microsomes from rats pretreated with phenobarbital or TCDD. Use of the inhibitor beta-diethylaminoethyl-diphenyl propylacetate (SKF 525-A) in vitro showed a more pronounced inhibition on microsomes from phenobarbital-treated rats than on microsomes from untreated or TCDD-treated rats. Gas chromatography-mass spectrometry have been used for the identification and quantification of pentachlorophenol and its metabolites.

Animals↗

Chronic toxicity of a pure and technical grade pentachlorophenol to Daphnia magna.

Chronic toxicity test procedures (static, with renewal) were used to determine the chronic toxicity of sublethal concentrations of a technical formulation of pentachlorophenol (PCP) and pure pentachlorophenol to Daphnia magna. Test organisms 48 +/- 12 h old were exposed for their entire lifespan (i.e., until death) to 0.01, 0.05, 0.1 and 0.5 mg technical PCP/L and 0.01, 0.087 and 0.1 mg pure PCP/L. Criteria used to assess chronic toxicity were mean time to appearance of the primiparous instar in the brood chamber, mean number of days to release of the first brood, mean number of broods produced per female, mean brood size per female, mean number of reproductive days, mean number of young produced per reproductive day per female and survivorship. Pentachlorophenol differentially affected maturation and reproduction but not survivorship or longevity. Mean number of broods produced per daphnid, length of the reproductive period, longevity and survivorship were insensitive criteria relative to mean time to appearance of the primiparous instar, time to release of first brood, brood size, and number of young produced per daphnid per reproductive day. Generally, there was little difference in toxicity of the three concentrations of pure PCP, for they significantly reduced mean brood size and rate of reproduction of young and significantly but differentially affected maturation. Technical PCP, at the highest concentration of 0.5 mg/L, significantly reduced mean brood size and the rate of production of young, and significantly delayed both time to appearance of the primiparous instar and release of the first brood. When differences in toxicity occurred, generally, pure PCP was more toxic than comparable concentrations of technical PCP. Although enhanced maturation was observed there was no compensatory reproduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Acute toxicity of pure pentachlorophenol and a technical formulation to three species of Daphnia.

The acute toxicity of a technical formulation of pentachlorophenol (PCP) and pure pentachlorophenol to three age classes of Daphnia magna, and adult D. pulex and D. galeata mendotae was determined by static toxicity tests. The influence of a number of factors on toxicity of PCP was also examined. The 48-hr LC50 estimates for adult daphnids of the three species exposed to pure PCP were 1.78, 4.59 and 0.51 mg/L, respectively, while those for the technical formulation were 2.57, 3.66 and 0.33 mg/L, respectively. There was little difference in toxicity between the technical and pure PCP; however, toxicity of both forms of PCP was influenced by duration of exposure, age (and/or size) and species of test organism and pH of the test solution. Pentachlorophenol caused a toxic response over a very narrow range of concentrations, with the greatest response occurring immediately between 0 and 24 hr. Pure PCP was equally toxic to all age classes of D. magna but susceptibility to technical PCP decreased with maturation. D. g. mendotae was ten times more sensitive than D. pulex to PCP. Pure PCP was significantly more toxic to D. magna at pH 5.5 than 7.0 with mean 48-hr LC50 values of 0.082 and 1.78 mg PCP/L, respectively. At 12 degrees C, the toxicity of both forms of PCP to D. g. mendotae and D. pulex did not differ significantly from that at 20 degrees C; however, technical PCP was significantly more toxic to D. magna at 12 degrees C for an exposure duration of 48 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

Cancer and occupational exposure to pentachlorophenol and tetrachlorophenol (Canada).

OBJECTIVE: The objective of this study is to assess the carcinogenicity of pentachlorophenol and tetrachlorophenol using data from the BC sawmill workers cohort study. METHODS: The cohort consisted of 27,464 men employed by 14 sawmills for 1 year or more between 1950 and 1995. Fatal (1950-1995) and incident (1969-1995) cancers were identified using national registries. Plant records and systematic interviews with senior employees were used to estimate dermal exposure. Comparisons were made with the general BC population and dose-response relationships were assessed using Poisson regression. RESULTS: There were 1,495 fatal cancer and 2,571 incident cancers. There were no large or statistically significant excesses of any of the specific cancers were observed compared to the general population. Internal analyses showed strong dose-response relationships for non-Hodgkin's lymphoma, multiple myeloma, and kidney cancer. These relationships were strongest when exposure was restricted to pentachlorophenol. The strength of the dose-response increased when exposure was lagged by 20 years. CONCLUSIONS: Dermal exposure to pentachlorophenol was associated with non-Hodgkin's lymphoma, multiple myeloma, and kidney cancer, but not with other cancers of a priori interest.

British Columbia↗

Alternating current studies of charge carrier transport in lipid bilayers. Pentachlorophenol in lecithin-cholesterol membranes.

Surface and interior electrical properties of lecithin-cholesterol bilayer membranes treated with the uncoupler pentachlorophenol have been determined on the basis of a.c. measurements over a wide range of frequencies (0.02 to 1000 kHZ). The method used depends on accurately determining the resistance of the aqueous solution in series with each individual membrane by extrapolating admittance data into infinite frequency. Loss tangent vs. frequency curves are corrected by subtracting out a loss contribution which is present in untreated membranes and is due, presumably, to dielectric relaxation. The results, which are useful below 100 kHZ, can be fitted to loss tangent curves computed for a three-element equivalent circuit consisting of frequency independent conductance-capacitance pairs, arranged in series to represent surface and interior properties of membranes. Interior conductances agree with net conductances obtained from d.c. measurements. The pH and concentration dependence of surface conductance is consistent with a scheme of transport in which a fixed number of surface binding sites are filled preferentially with neutral pentachlorophenol molecules, which in turn dissociate to supply protons to the aqueous phase. Surface capacitances range from 15 to 90 times that of interior capacitance and show a systematic increase with pentachlorophenol concentration at high pH, and a decrease with concentration at low pH.

Biological Transport, Active↗

The influence of sterols on pentachlorophenol-induced charge transfer across lipid bilayers studied by alternating current methods.

The frequency dependence of membrane admittance has been determined for a series of phosphatidylcholine/sterol/n-decane bilayers in the presence of an aqueous environment containing pentachlorophenol. Variations in the results among membranes can be related to differences in the kinetic parameters of a kinetic model of pentachlorophenol-induced charge transport by characterizing both measurements and model behavior in terms of a common equivalent circuit. The kinetic model assumes a three-layer structure for the membrane and immediate environment. Data from membranes formed with beta-hydroxysterols having a flat ring structure and an intact side-chain (cholestanol, cholesterol, 7-dehydrocholesterol), after correction for sterol-induced membrane thinning, suggest that these sterols affect charge translocation by altering both interior fluidity and surface dipolar fields. The effects almost cancel for the case of cholesterol. These sterols also affect interfacial processes, either by inhibiting proton exchange between the aqueous and lipid environments, or by suppressing the adsorption of pentachlorophenol anions. Stigmasterol, coprostanol and epicholesterol cause only minor alterations in both translocation and interfacial processes. None of the sterols investigated has a significant influence on the capacitance of the interfacial region.

Animals↗

Formation of pentachlorophenol as the major product of microsomal oxidation of hexachlorobenzene.

On incubation of [14C]-hexachlorobenzene with microsomes from livers of rats induced with hexachlorobenzene, the major product (80-90%) was pentachlorophenol. The only other detectable metabolite, tetrachlorohydroquinone (4-15%), was presumably formed from pentachlorophenol. A considerable amount of radioactivity (5-10% of the amount of extracted metabolites) was covalently bound to protein. Microsomes derived from male hexachlorobenzene--induced rats gave by far the highest conversion (approx. 1% of substrate). Microsomes from female hexachlorobenzene--induced rats were 3 times less efficient. Microsomes from untreated and 3-methyl-cholanthrene--treated animals gave less than 5% of the amount of pentachlorophenol formed by microsomes from hexachlorobenzene--induced male rats, while phenobarbital and aroclor 1254-induction resulted in formation of 51% and 34% respectively.

Animals↗

Use of pentachlorophenol as long-term inhibitor of sulfation of phenols and hydroxamic acids in the rat in vivo.

Inhibition of sulfation of the phenolic compound harmol (7-hydroxy-1-methyl-9H-pyrido[3,4-b]indole) by pentachlorophenol (PCP) was studied in the Wistar rat: PCP was administered in various ways to find a convenient method for long-term inhibition of sulfation. High doses of PCP or sodium pentachlorophenolate (NaPCP) in the diet (350 ppm) or NaPCP in the drinking water (1.4 mM) of Wistar rats for one week inhibited the sulfation of harmol by 30-45%. The plasma concentration of PCP in rats with NaPCP (1.4 mM) in their drinking water was highest (270 microM) in the period that the animals were kept in the dark and consumed food and water. This is explained by a rapid elimination: the elimination of PCP from plasma, after intravenous administration, showed a biphasic disappearance curve with half-lives of 2.17 and 7.24 hrs, respectively. This is much faster than in Sprague-Dawley rats. A log-linear correlation was found between the plasma concentration of pentachlorophenol and the inhibition of harmol sulfation. Although administration of NaPCP to rats in their drinking water inhibited the sulfation of harmol only by 45%, it inhibited the sulfation of the carcinogenic arylhydroxamic acid N-hydroxy-2-acetylaminofluorene by 70-75%.

Animals↗

Development of a standardized reproduction toxicity test with the earthworm species Eisenia fetida andrei using copper, pentachlorophenol and 2,4-dichloroaniline.

This article describes a standardized test method for determining the effect of chemical substances on the reproduction of the earthworm Eisenia fetida andrei. It is based on the existing guidelines for acute toxicity testing with earthworms, and for reasons of standardization the same artificial soil substrate and earthworm species were chosen as prescribed by these guidelines. After being preconditioned for one week in untreated soil, earthworms are exposed to the chemical substances for 3 weeks. The number of cocoons produced is determined, and cocoons are incubated in untreated artificial soil for 5 weeks to assess hatchability. Results are presented from toxicity experiments with pentachlorophenol, copper, and 2,4-dichloroaniline. For these compounds no-effect levels (NEL) for cocoon production were 32, 60-120, and 56 mg.kg-1 dry soil, respectively. Hatching of cocoons was influenced by pentachlorophenol (NEL, 10 mg.kg-1), but not by copper and dichloroaniline. Following exposure, earthworms were incubated in clean soil again to study the possibility of recovery of cocoon production. For copper and dichloroaniline earthworms did recover cocoon production to a level as high as the control level or even higher; in case of pentachlorophenol, cocoon production was still reduced after 3 weeks in clean soil.

Aniline Compounds↗

Acute toxicity of monochlorophenols, dichlorophenols and pentachlorophenol in the mouse.

Acute oral LD50 values were determined for 2-, 3-, and 4-chlorophenol, 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5 dichlorophenol and pentachlorophenol in male and female mice. LD50 values (mg/kg) ranged from 117 (females) and 177 (males) for pentachlorophenol to 2389 (females) and 2643 (males) for 3,5-dichlorophenol. It was found that 2-chlorophenol and 3-chlorophenol were considerably more toxic than the dichlorophenol series. Values for males and females were generally similar, the major differences being with pentachlorophenol and 2,5-dichlorophenol, where in both cases the female LD50 was lower.

Animals↗

Development of a solid-phase microextraction method for direct determination of pentachlorophenol in paper and board samples: Comparison with conventional extraction method.

A solid-phase microextraction (SPME) method has been developed for the determination of pentachlorophenol (PCP) in paper and board samples. The analytical procedure involves direct extraction of PCP from paper and board samples and determination by gas chromatography with electron capture detection (GC-ECD). Two kinds of commercially available fibres; 100 microm polydimethylsiloxane (PDMS), apolar, and 85 microm polyacrylate (PA), quite polar, were evaluated to determine the extraction efficiency of pentachlorophenol. Parameters affecting the extraction process, such as temperature and time, were studied. Moreover, time of desorption and the effect of addition of salt were also investigated. The optimized procedure was applied to the analysis of pentachlorophenol (PCP) in five samples of virgin and recycled paper and board. The PCP content was determined by GC-ECD. To evaluate the effectiveness of the proposed method, it was compared with conventional extraction method with liquid-liquid extraction and derivatization. Detection limit of 0.015 microg/g for PCP in paper was achieved with a RSD of 14%.

Chemical Fractionation↗

Pentachlorophenol association with fulvic acids from recycled wastes.

The apparent water solubility of pentachlorophenol was measured at pH=6 and at 25 degrees C in pure water, aqueous solutions of three salts (NaCl, KNO(3) and CaCl(2) at 0.010, 0.10 and 1.0M) and in aqueous solutions of three fulvic acids samples extracted from a natural soil (sFA), composted sewage sludge (csFA) and composted livestock's material (lsFA). A solubility enhancement method was developed for the measurement of partition coefficients (K(oc), L/kg organic carbon). Pentachlorophenol associates strongly with the fulvic acid samples and the calculated K(oc) were the following (averages and standard deviations): (sFA) (211+/-22) x 10(2), (csFA) (253+/-26) x 10(2), (lsFA) (235+/-10) x 10(2). For comparison purposes the K(oc) for pyrene were also calculated for the three FA samples and were the following: (sFA) (119+/-10) x 10(2), (csFA) (239+/-21) x 10(2), (lsFA) (92+/-10) x 10(2). The analysis of variance (one-way ANOVA) of the effect of the type of FA sample on the solubilization of pentachlorophenol and pyrene shows that this factor causes significant differences on the aqueous solubilization of these two organic substances.

Benzopyrans↗

Photocatalytic degradation of pentachlorophenol on TiO2 sol-gel catalysts.

The photocatalytic degradation of pentachlorophenol (PCP) in aqueous solution was investigated using TiO2 catalysts. The samples were prepared by the sol-gel method using different gelation pH and different calcination temperatures. The solids were characterized by specific surface area, X-ray diffraction, UV-Vis absorbance, FTIR and pentachlorophenol adsorption. The catalytic activity of the solids was evaluated in a conventional photoreactor at 298 K using 30 ppm of pentachlorophenol. It was found that the reaction follows a first-order reaction and the kinetic constant values change slightly with the pH of gelation and more significantly with the calcination temperature.

Adsorption↗

Pentachlorophenol and phenanthrene biodegradation in creosote contaminated aquifer material.

Contamination of the subsurface environment at the Libby Superfund Site, Montana, includes polycyclic aromatic hydrocarbons and f1p4achlorophenol due to accidental spills and improper disposal of wood preserving wastes. Biodegradation is a treatment technology gaining wide application in the treatment of hazardous waste sites. A microcosm study was conducted to evaluate the effect of temperature, sampling depth, nutrient addition, and oxygen on the biodegradation potential of phenanthrene and pentachlorophenol in aquifer samples using radiolabeled chemicals. Mineralization of phenanthrene reached 14% but was less than 1% for pentachlorophenol over the 56 day incubation period. Phenanthrene mineralization in microcosms at 10 degrees C was not significantly different from those at 20 degrees C. This may have been due to microbial community acclimation to lower temperatures at the site. Average volatilization was less than 2% for both phenanthrene and pentachlorophenol. After 56 days, most of the radiolabeled chemical was either solvent extractable or soil bound.

Biodegradation, Environmental↗

A test battery for the ecotoxicological evaluation of pentachlorophenol.

Experimental bioassays are currently used in ecotoxicology and environmental toxicology to provide information for risk assessment evaluation of new chemicals and to investigate their effects and mechanisms of action; in addition, ecotoxicological models are used for the detection, control and monitoring of the presence of pollutants in the environment. As a single bioassay will never provide a full picture of the quality of the environment, a representative, cost-effective and quantitative test battery should be developed. The effects of pentachlorophenol were studied using a battery of ecotoxicological model systems, including immobilization of Daphnia magna, bioluminiscence inhibition in the bacterium Vibrio fischeri, growth inhibition of the alga Chlorella vulgaris, and micronuclei induction in the plant Allium cepa. The inhibition of cell proliferation and MTT reduction were investigated in Vero cells. Neutral red uptake, cell growth, MTT reduction, lactate dehydrogenase leakage and activity were studied in the salmonid fish cell line RTG-2, derived from the gonad of rainbow trout. Pentachlorophenol was very toxic for all biota and cells. The system most sensitive to pentachlorophenol, was micronuclei induction in A. cepa, followed by D. magna immobilization, bioluminescence inhibition in V. fischeri bacteria at 60 min and cell proliferation inhibition of RTG-2 cells at 72 h. Inhibition of cell proliferation and MTT reduction on Vero monkey cells showed intermediate sensitivity.

Animals↗