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PubMed2001

The immunochemical detection of stress proteins in activated sludge exposed to toxic chemicals.

The heat shock protein, GroEL, was found to be induced in activated sludge cultures exposed to perturbations of chemicals (cadmium, pentachlorophenol, and acetone) or heat stress. In laboratory activated sludge reactors, GroEL was rapidly induced (within minutes) in the presence of 5 mg/l or greater total cadmium. At 5 mg/l cadmium, however, moderate to insignificant changes in activated sludge process performance indicators [effluent suspended solids concentration, chemical oxygen demand (COD) removal, and specific oxygen uptake rate] were observed. As total cadmium concentrations increased above 5 mg/l, there was a significant and consistent increase in effluent volatile suspended solids concentrations from activated sludge sequencing batch reactors relative to unstressed controls. These results indicate that stress proteins may serve as sensitive and rapid indicators of mixed liquor toxicity which can adversely impact treatment process performance, but that GroEL may not be a good candidate protein for this purpose.

Blotting, Western↗
PubMed2003

Simulation of bioremediation of chlorophenols in a sandy aquifer.

Bioremediation of consecutive spills of phenol, 2-chlorophenol (2-MCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlororphenol as single pollutants was investigated in eight pilot plant scale sand columns system (100 cm l, 6 cm ID), simulating the conditions, which could be created in the saturated zone of a pristine aquifer following an accidental spill. Bioremediation in this study consisted of re-circulating local groundwater through the polluted site in a controlled manner following a closed-loop configuration. Intrinsic microbial development was enhanced by adding the necessary nutrients. Consecutive accidental spills of 480-mg phenol/kg soil; 140-mg 2-MCP/kg; 14-mg 2,4,6-TCP/kg soil and 17-mg pentachlorophenol (PCP)/kg soil under saturated conditions and a continuous specific discharge of 0.56 cm min(-1) were simulated. Degradation curves demonstrated first-order kinetics. Biodegradation rates (k1) were influenced by consecutive exposures. Calculated rate constants for biodegradation for sole substrate experiments were in the range of 0.06-0.15 day(-1), 0.21-1.20 day(-1), 0.04-2.28 day(-1) and 0.01-0.03 day(-1) for phenol, 2-MCP, 2,4,6-TCP and PCP, respectively. The acclimation of the aquifer to simulated consecutive accidental spills was found to be directly proportional to the cumulative load of each single chlorophenol. A relationship between the octanol water partitioning (Kow) values and the experimental degradation rates (k1) was found.

Biodegradation, Environmental↗
PubMed2001

No enhancement in bioconcentration of organic contaminants by low levels of DOM.

The aim of the present work was to systematically study the effect of low concentrations of dissolved organic matter (DOM) on the bioconcentration of organic contaminants, in order to show whether the phenomenon of enhanced bioconcentration factors (BCFs), that has been reported in the literature, is generally found at low levels of DOM or if BCF enhancements are more likely due to a random scatter in the experimental data. The first part of the study tested the hypothesis that low levels of DOM affect the uptake kinetics of organic contaminants, leading to transient enhancements of BCFs, relative to DOM-free controls, which could have been reported as BCF enhancements in short-term studies. We found that the presence of low concentrations of two different types of DOM consistently decreased the bioconcentration of benzo[a]pyrene (BaP) in the water flea Daphnia magna at all exposure times (1-24 h), and that no transient BCF enhancements occurred. The second part of the study systematically investigated if low concentrations of DOM from a wide range of different aquatic systems can cause enhancements in the bioconcentration of organic contaminants. Water fleas were exposed to combinations of four different organic contaminants (BaP, tetrachlorobiphenyl, pentachlorophenol and naphthalene) with low concentrations of 12 different types of DOM that had been collected from various regions throughout Europe. In several of the DOM treatments, we found mean BCFs being higher than mean BCFs in the controls (especially for naphthalene). This shows that the experimental setup used in this study (and similarly in previous studies) can produce seeming BCF enhancements at low concentrations of DOM. However, statistical analyses showed that treatment means were not significantly different from control means. Thus, this systematic study suggests that the BCF enhancements that have been reported in the literature are more likely the result of random, experimental variations than the result of a systematic enhancement of bioconcentration.

Animals↗
PubMed2001

Dioxin and dioxin-like PCB impurities in some Japanese agrochemical formulations.

The profile and amount of dioxin impurity in agrochemicals were studied through detailed analysis of historic Japanese formulations. The chemicals analyzed include pentachlorophenol (PCP), 2,4,6-trichlorophenyl-4'-nitrophenyl ether (chloronitrofen, CNP), 2,4-dichlorophenyl-4'-nitrophenyl ether (nitrofen, NIP), tetrachloro-iso-phthalonitrile (chlorothalonil, TPN), 2-methyl-4-chloro-phenoxyacetic acid (MCP) and 2,4-dichlorophenoxyacetic acid (2,4-D). Among the six, two herbicides, PCP and CNP, produced during the 1960s and 1970s, contained very high concentrations of PCDD/DFs and TEQ. Others contained relatively low concentrations of PCDD/DFs. Dioxin-like PCB concentrations in all chemicals studied were low and their contributions to TEQ were negligible. The total dioxin emissions from the use of agrochemicals in Japan during the past 40 years (1955-1995) were estimated to be about a few hundred thousand kg of PCDD/DFs and 250 kg of WHO-TEQ from PCP and 190 x 10(3) kg of PCDD/DFs and 440 kg of WHO-TEQ from CNP. The major dioxin congeners present in PCP formulations were highly chlorinated PCDD/DFs that can be formed by the coupling of PCP and/or 2,3,4,6-tetrachlorophenol, and those in the CNP formulations were tetra- to hexa-chlorinated PCDD/DFs that can be formed from 2,4,6-trichlorophenol and/or 2,3,4,6-tetrachlorophenol.

Agriculture↗
PubMed2001

Evaluation of TCDD biodegradability under different redox conditions.

Polychlorinated dibenzo-p-dioxins have been generated as unwanted by-products in many industrial processes. Although their widespread distribution in different environmental compartments has been recognized, little is known about their fate in the ultimate environment sinks. The highly stable dioxin isomer 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been called the most toxic compound known to man. In this laboratory microcosm study, TCDD bioavailability was evaluated under five reduction/oxidation (redox) conditions including aerobic biodegradation, aerobic cometabolism, methanogenesis, iron reduction, and reductive dechlorination. Activated sludge and aquifer sediments from a TCDD and a pentachlorophenol (PCP) contaminated site were used as the inocula. Acetate, sludge cake, and cane molasses were used as the primary substrates (carbon sources) in cometabolism and reductive dechlorination microcosms. After a 90-day incubation period, microcosms constructed under reductive dechlorination conditions were the only treatment showing promising remediation results. The highest TCDD degradation rate [up to 86% of TCDD removal (with an initial concentration of 96 microg/kg of soil)] was observed in the microcosms with anaerobic activated sludge as the microbial inocula and sludge cakes as the primary substrates. Except for reductive dechlorination microcosms, no significant TCDD removal was observed in the microcosms prepared under other conditions. Thus, application of an effective primary substrate to enhance the reductive dechlorination process is a feasible method for TCDD bioremediation. Bioremediation expense can be significantly reduced by the supplement of some less expensive alternative substrates (e.g., sludge cakes, cane molasses). Results would be useful in designing a scale-up in situ or on-site bioremediation system such as bioslurry reactor for field application.

Bacteria, Aerobic↗
PubMed2001

Polychlorinated dibenzo-p-dioxins and dibenzofurans in plywood combustion gas.

Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/DF) levels in plywood combustion gas were investigated for the effects of ammonium chloride (NH4Cl) and paint. For combustion systems in which neither NH4Cl nor paint were present in the plywood samples, total amounts of PCDD/DFs in the combustion gas were in the order of 35-529 ng/Nm3, and were higher in the systems with softwood trees than broadleaf ones, depending on the Cl concentrations. For the systems with added NH4Cl and no paint, and those without NH4Cl but were painted, higher PCDD/ DF rates were observed at combustion temperatures of 270 degrees C and 500 degrees C, respectively. However, for the systems with both NH4Cl and paint, their amounts in the range of 0.6-13 ng/Nm3 were the lowest in all systems. The PCDD/DF abundance profiles were similar to their patterns in pentachlorophenol (PCP). Furthermore, it was found that the 2,3,7,8-chlorine substituted penta- and hexa-CDDs contributed more than other 2,3,7,8-chlorine substitutes to toxicity equivalency (TEQ).

Air Pollutants↗
PubMed2001

Congener-specific characterization of PCDDs/PCDFs in atmospheric deposition: comparison of profiles among deposition, source, and environmental sink.

In order to examine the input of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs) from various airborne sources to environmental sinks, the atmospheric deposition of congener-specific PCDDs/PCDFs was investigated. Homologue and congener profiles of atmospheric depositions were compared with those of sources and environmental sinks to identify the relationship among atmospheric depositions, sources, and environmental sinks. Moreover, factor analysis was used to detect similarities, differences, and relationships of the variations in deposition fluxes among congeners within the same and different homologues. The results showed that the congener profiles of the atmospheric depositions were primarily determined by those of combustion emissions. Several congeners in some specific samples showed higher proportions within each homologue compared with representative depositions. This result can be partly explained by the influence of impurities in herbicides, 1,3,5-trichloro-2-(4-nitrophenoxy) benzene (CNP) and pentachlorophenol (PCP). The congener profiles of combustion emissions, representative depositions, and urban soils were very similar although their homologue profiles varied. This implied that PCDDs/PCDFs in the urban soils originate from the deposition of combustion emissions and that all congeners within each homologue behave identically in air and soil. Although the congener profiles of the representative depositions were different from those of the sediments in Tokyo Bay and the soil of a paddy field, the combination of congener profiles of the representative depositions and of the impurities in herbicides. CNP and PCP, can explain the congener profiles of the sediments and the paddy field. This study showed that congener-specific data are useful for source identification.

Agriculture↗
PubMed2002

Time-dependent toxicity in the long-term inhibition assay with Vibrio fischeri.

The significance of the duration of exposure for the detection of toxicity was evaluated in a 24 h long-term bioluminescence inhibition assay with Vibrio fischeri. Bioluminescence was measured over the time course of 24 h using microplates. The undisturbed luminescence of controls in this assay exhibited characteristic dynamics: a decrease within a period of 12 h with minimal luminescence followed by a continuous increase of luminescence beyond the starting value. To evaluate the toxic influence of compounds chosen to reflect immediate and delayed toxicity to V. fischeri, the bioluminescence was measured for 24 h at 30 min intervals. Luminescence inhibition patterns were recorded for subdinoseb, pentachlorophenol and 2,4,5-trichlorophenol) and for substances causing delayed toxicity (chloramphenicol, nalidixic acid and phosphomycin). The toxic influence of substances with immediate toxicity was observed directly after application, whereas the toxicity patterns of substances with delayed toxicity developed specifically over the time according to the different involved mechanisms of action. It is concluded that knowledge about time to toxicity in bioassays is necessary in order to identify suitable test endpoints as well as to recognize potential hazards related to time-dependent toxicity.

Luminescent Measurements↗
PubMed2002

Persistent organochlorine pollutants in human serum of 50-65 years old women in the Flanders Environmental and Health Study (FLEHS). Part 1: Concentrations and regional differences.

In 1999, a campaign of the Flemish Ministry of Health, Belgium was set up to assess pollutant concentrations and related health effect biomarkers in humans living in two regions of Flanders. The study was called the 'Flemish Environment and Health Study' (FLEHS). One of the goals was to measure present concentrations of persistent organochlorine pollutants in a Flemish population and to compare values obtained from pooled and individual serum samples. Concentrations of selected organochlorine pesticides, polychlorinated biphenyls (PCB) and polychlorinated dibenzo-p-dioxins (PCDD) and furans (PCDF) were measured by gas chromatography-mass spectrometry. TEQ values were also assessed by Chemical-Activated LUciferase gene eXpression (CALUX) bioassay. The study population consisted of 200 women between 50 and 65 years living in two areas of Flanders, Belgium. Because of the large volumes serum needed for all measurements, the concentrations of organochlorines were measured in 47 pooled serum samples originating from these women. The concentrations of the indicator PCBs (359.8 ng/g fat) and organochlorine pesticides (hexachlorobenzene, p,p'-dichlorodiphenyldichloroethylene, p,p'-dichlorodiphenyl-trichloroethane, lindane and pentachlorophenol), were comparable to those found in other European countries. The concentrations of PCDD/PCDFs showed another picture. With a median value of 48 pg WHO-TEQ/g fat, the women had 2-fold higher levels than a comparable age group from Germany examined in 1996. The mean total WHO-TEQ including PCDD/F, non-ortho and mono-ortho PCBs was 72.7 pg WHO-TEQ/g fat, whereas the CALUX-TEQ mean value was only 35.0 pg TEQ/g fat. In order to assess the pooling procedure, indicator PCBs and CALUX-TEQs were measured in all 200 individuals that were integrated in the pools. The measured values were comparable to the pool results: 390.0 ng/g fat and 41.6 pg TEQ/g fat respectively. It was concluded that pooling of serum samples offers the possibility to measure exposure in the whole study population on a more cost-effective way. However, because of statistical power loss and no possibility of confounder adjustment, pooling is not the most effective way to study regional differences.

Aged↗
PubMed2003

Source and behavior analyses of dioxins based on congener-specific information and their application to Tokyo Bay basin.

Identification of pollution sources and estimation of their contribution to dioxin pollution are important for taking better countermeasures against such sources. The information based on seventeen 2,3,7,8-chlorine-substituted congeners and 10 homologues is usually not sufficient for source identification. The usefulness of detailed congener-specific information of tetra- to octachlorinated polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans was examined by principal component analysis and compared with conventional dioxin information. It was revealed that congener-specific information was far more effective for source identification than conventional information. For source apportioning, it was shown that multiple regression analysis with detailed source congener profiles could be carried out successfully when calculations were performed for individual homologues. This was because of the large variation in homologue composition in source dioxin profiles in addition to the difference in environmental behavior among the homologues. The newly proposed methods for statistical analysis were applied to the estimation of dioxin mass balance in Tokyo Bay basin. It was found that Tokyo Bay sediment core contained dioxins from three major sources: combustion, pentachlorophenol (PCP), and chloronitrophen (CNP). PCP and CNP contained large amounts of dioxin as impurity and were used extensively as paddy field herbicides in Japan in the past. The total dioxin load from the two herbicides to the basin during the past 45 years (1951-1995) was estimated to be five times larger than that from combustion source in terms of toxic equivalents (WHO-TEQ). However, in the surface sediment of the bay, the contribution from the herbicides was nearly equal to that from combustion. The herbicide contribution peaked during the 1960s and 1970s and gradually decreased thereafter.

Agriculture↗
PubMed2003

The evaluation of the equilibrium partitioning method using sensitivity distributions of species in water and soil.

The equilibrium partitioning method (EqP-method) can be used to calculate soil quality standards (expressed in mg/kg) from aquatic quality standards (expressed in microg/l) using a partitioning coefficient. The validity of this application of the EqP-method was studied comparing aquatic with terrestrial toxicity data. The data set collected for deriving environmental quality standards in the Netherlands, was used for this study. For 10 organic substances (chlorpyrifos, atrazine, carbofuran, pentachlorophenol, chlordane, aldrin, trichlorobenzene, heptachlor, trichlorophenol and trichloroethene) and for 8 metals, sufficient data were available. The aquatic toxicity data were multiplied by the partitioning coefficient in order to obtain aquatic data expressed in mg/kg. For some compounds the terrestrial toxicity data were significantly higher than the aquatic data but for other compounds it was the other way around. These differences indicate that the EqP-method can give significant over-or underestimations, due to inaccurate partitioning coefficients or differences in species sensitivities. These over- or underestimations can have an impact on the setting of environmental quality standards which are based on the hazardous concentration 5% (HC5) values. The uncertainty in the calculation of HC5 values attributed to the use of the EqP-method, was quantified. The HC5 values derived using the EqP-method were in 5% of the cases more than 20 times higher than the corresponding HC5 values that were derived directly from soil toxicity tests. Despite of this uncertainty the use of the EqP-method can still be advocated for setting soil quality guidelines when only a very limited number of terrestrial toxicity data are available.

Animals↗
PubMed1997

Pattern analysis of the variation in the sensitivity of aquatic species to toxicants.

Our aim in this study was to identify groups of species showing a similar pattern in their sensitivity to toxicants and to relate the patterns to the mode of toxic action and biological species characteristics. A data matrix was composed of acute toxicity data for 26 aquatic species and 21 compounds. Most of the variation in the toxicological data was due to differences in toxicity of compounds and not intrinsic differences between species, so that practically every species can be used to order compounds with respect to average toxicity. Compounds with high overall toxicity also had large interspecies variation in sensitivity. The toxicity of non-polar narcotics correlated well with the log Kow. Compounds with a specific or reactive mode of action were more than a factor 10 toxic than predicted by their log Kow. Patterns in species sensitivity were more diffuse because only part of the variance in species sensitivity could be explained. Fishes and amphibians were more sensitive to dieldrin, lindane and pentachlorophenol than were invertebrates. Among the arthropods, the Phyllopoda (daphnids) were the most sensitive species. They were very sensitive to aniline, the heavy metals, malathion and parathion.

Analysis of Variance↗
PubMed1998

Lipid-containing semipermeable membrane devices (SPMDs) as concentrators of toxic chemicals in the lower Fraser River, Vancouver, British Columbia.

Semipermeable membrane devices (SPMDs) were deployed in the water column and in the sediments of the Lower Fraser River (B.C., Canada) to compare the levels and the congener profiles of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and non-ortho-chlorinated biphenyls (N-o,o1-PCBs) against those sampled by an Infiltrex resin column water sampler. Also the relationship between what was present in the ecosystem as sampled by SPMDs and what was accumulated in the tissue of resident benthic-feeding fish was explored. Only the lipid portion of the SPMDs was prepared for analysis, due to some technical difficulties in cleaning the polyethene tubing. The calculated water concentrations as obtained from the SPMD experiments were similar to those obtained by using the Infiltrex sampler. The PCDD/F congener distribution pattern shows multiple source inputs from pulp mill, pentachlorophenol formulations, and combustion. The fish tissue data showed similar congener profiles to those obtained from the SPMDs.

Animals↗
PubMedDate not supplied

Origin attribution of polychlorinated dibenzo-p-dioxins and dibenzofurans in sediment and soil from a Japanese freshwater lake area through congener-specific data analysis.

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in sediment and soil from a freshwater lake area were congener-specifically determined. The obtained data were examined to estimate the major origins of these compounds, with the aid of principal component analysis (PCA). Four major principal components (PCs) were obtained, and three of them were attributed to PCDDs/PCDFs in the atmosphere, in a diphenyl ether herbicide and in pentachlorophenol, based on congener-specific comparisons with references. One PC remained unattributed. These four were interpreted as the major origins of PCDDs/PCDFs in the area. The relative influence of the origins was also investigated.

Agriculture↗
PubMed1998

Comparative sensitivity of 20 bioassays for soil quality.

Increasing evidence suggests that the use of a single bioassay will never provide a full picture of the quality of the environment. Only a test battery, composed of bioassays of different animal and plant species from different trophic levels will reduce uncertainty, allowing an accurate assessment of the quality of the environment. In the present study, a test battery composed of 20 bioassays of varying biological endpoints has been compared. Apart from lethality and reproductive failure in earthworms, springtails, nematoda, algae and vascular plants, these endpoints also included bioavailibility of metals (bacteria), heat-shock induction (nematodes, algae), DNA damage (bacteria, earthworm, vascular plants), beta-galactosidase (Daphnia) and esterase activity (algae) and a range of immunological parameters (earthworm). Four chemicals (cadmium, phenol, pentachlorophenol and trifluralin)--each representing a different toxic mode of action--were applied in a dilution series (from 1 mg/kg up to 1000 mg/kg) onto OECD standard soil. The tests have been performed both on these artificially contaminated soil samples and on aqueous extracts subsequently obtained from these soils. The results show that the immunological parameters and the loss of weight in the earthworms were among the most sensitive solid-phase assays. Esterase inhibition and heat-shock induction in algae were shown to be extremely sensitive when applied to soil extracts. As previously shown at the species level, no single biological endpoint was shown to be the most sensitive for all four modes of toxic action.

Animals↗
PubMed1999

Degradation of phenolic and chloroaromatic compounds by Coprinus spp.

Three species of Coprinus: C. sp, C. cinereus and C. micaceus were compared on solid media for some aspects of their physiological behaviour and cultural requirements (temperature, pH, substrate). Constitutive extracellular enzymatic activities were also determined. The Coprinus spp. exhibited different physiological and cultural features. Cultures of the 3 Coprinus species in synthetic liquid medium showed an efficient degradation of phenolic lignin model compounds (catechol, ferulic acid, guaiacol, phenol, protocatechuic acid syringic acid and vanillic acid) and pentachloronitrobenzene, while pentachlorophenol was not metabolized after 5 days perhaps because of a strong adsorption on mycelial biomass. It was suggested that phenoloxidases were not necessarily required for the metabolization of these compounds. Coprinus species may share a common degrading system for monomeric phenolic and chloroaromatic compounds.

Benzene↗
PubMed2000

Estimation of dioxin emission from fires in chemicals.

The formation of the 17 toxic 2,3,7,8-substituted PCDDs and PCDFs during combustion of selected chemicals were measured by high-resolution GC/MS. The 16 chemicals studied were commonly used chlorinated pesticides, industrial chemicals, and PVC. In a series of experiments carried out in a DIN 53,436 furnace, 2.5 g of these compounds were burned at 500 degrees C and 900 degrees C, respectively. The resultant yields ranged from 740 ng ITEQ/g for pentachlorophenol, to below 0.01 ng ITEQ/g for PVC and dichlobenil. The results show that some chemicals generate PCDD/F in very high--possibly dangerous--amounts during burning, whereas others generate insignificant amounts. The influence of scale were studied for chlorobenzene and 4-chloro-3-nitro-benzoic acid in additional experiments, carried out in a cone calorimeter burning 20 g substance, and in ISO 9705 room test burning about 50 kg. A good agreement between the results for large and small scale indicated that formation of PCCD/F during a fire may be estimated from laboratory experiments. This suggest laboratory test may be used to screen for chemicals posing a hazard for release of PCDD/F during fires.

Benzofurans↗
PubMed2000

Bioassays with Vibrio fischeri for the assessment of delayed toxicity.

The standardized bioluminescence assay with Vibrio fischeri underestimates the aquatic toxicity of chemicals which interfere with metabolic pathways supporting long term processes like growth and reproduction due to its short incubation time (30 min). Therefore this short term assay was compared with two alternative bioassays with prolonged incubation times using the same test organism: the growth inhibition assay (7 h) and the long term bioluminescence assay (24 h). Two sets of compounds were selected to reflect acute and delayed toxicity. The first group comprised pentachlorophenol, dodecylpyridiniumbromide and 3,4-dichloroaniline and the second nalidixic acid, chloramphenicol and streptomycinsulfate. The effects of compounds with acute toxicity are determined with similar sensitivity in all bioassays. Substances with delayed toxicity show only minor or no toxicities in the standardized short term bioassay but severe effects in both long term bioassays independent of the parameter used. It is concluded that the standardized short term bioluminescence assay exhibits serious limitations for the assessment of aquatic toxicity. The long term bioassays, however, may help to overcome these limitations.

Biological Assay↗