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Archives of Environmental Contamination and Toxicology (v.35, #4)

Monitoring and Mass Budget for Mercury in the Everglades Nutrient Removal Project by C. J. Miles; L. E. Fink (pp. 549-557).

The Everglades Nutrient Removal Project (ENRP) is a 1,545-ha prototype wetland constructed to test a larger system of stormwater-treatment areas that is being used to remove agricultural nutrients and help restore the remnant Everglades. Concerns that the ENRP may lead to mercury bioaccumulation as observed in other newly created reservoirs resulted in an effort to construct a mercury mass budget and measure bioaccumulation in aquatic organisms. For the first 2 years of operation, total mercury (THg) and methylmercury (MeHg) concentrations in water decreased significantly a short distance into the ENRP, probably through particle settling. During both years, THg concentrations in largemouth bass were about 0.1 μg/g throughout the ENRP while the adjacent Water Conservation Area bass were at or above the state health advisory level of 0.5 μg/g. THg levels in mosquitofish were lower than levels found in bass, and mosquitofish mercury concentrations in the interior of the ENRP were significantly lower than the inflow and outflow sites. The major THg pool was the sediment while less than 1% the total mass was stored in vegetation, water, and fish. The major MeHg pool also was the sediment but vegetation, water, and fish were significant fractions. Mass budget estimates showed the inflow pump and rainfall to be the major sources of THg, while the outflow pump was the major output. The inflow pump was the major source of MeHg while the outflow pump was the major output. Evasion of elemental mercury estimated by the stagnant-film model indicated a minor loss, but field measurements over cattails suggested that evasion may be the major pathway. When all inputs and outputs were considered, the ENRP removed about 70% of the THg and MeHg masses in the first 2 years of operation.

Organotin Compounds in Water, Sediment, and Biological Samples from the Port of Osaka, Japan by H. Harino; M. Fukushima; Y. Yamamoto; S. Kawai; N. Miyazaki (pp. 558-564).

Butyltin (Bts) and phenyltin compounds (Pts) were measured in water, sediment, plankton, and mussels collected from eight stations in the harbor area of the Port of Osaka in 1996, and were compared with those of Otsuchi Bay. The levels of tributyltin (TBT) compounds in all samples from the Port of Osaka were slightly high in marinas and mooring areas of small and medium-hull vessels. Of total Bts, the ratio of TBT was under 50% in water and was dominant in sediment, plankton, and mussels. Triphenyltin (TPT) compounds in water were not detected. TPT was present at lower levels than TBT in sediment, plankton, and mussels. Of total Pts, monophenyltin (MPT) compounds and diphenyltin (DPT) compounds represented a high proportion in sediment, while TPT was dominant in plankton and mussels. The concentrations of TBT in water from the Port of Osaka were lower than those from Otsuchi Bay, however TBT concentrations in sediment, plankton, and mussels from the Port of Osaka were higher than those from Otsuchi Bay. The difference of TBT concentration among stations in the Port of Osaka was slight. In contrast, the levels of TBT in Otsuchi Bay were markedly higher at a station near the shipyard. Though TPT in water from the Port of Osaka was not detected, trace amounts of TPT was found in seawater from Otsuchi Bay. The levels and detected frequencies of TPT in sediment, plankton, and mussels from the Port of Osaka were lower than in those from Otsuchi Bay. The partition coefficients of Bts to sediment, plankton, and mussels from the Port of Osaka were higher than those of dibutyltin (DBT) compounds and MBT and those of TBT to plankton and mussels were higher than those in sediment. The partition coefficients of TBT to sediment and biological samples from the Port of Osaka were higher level than those in Otsuchi Bay.

Selection of an Aquatic Indicator Species to Monitor Organic Contaminants in Trophically Simple Lotic Food Webs by G. J. Scrimgeour; D. Wicklum; S. D. Pruss (pp. 565-572).

A four-step procedure was used to identify an aquatic macroinvertebrate with which to monitor organic contaminant burdens in trophically simple lake food webs of Alberta, Canada. We identified leeches (Oligochaeta: Hirudinea) as the potential indicator assemblage (Step 1), and then documented their abundance and distribution in 16 lakes to identify a species-level bioindicator (Step 2). The latter two steps involved identifying the number and level of organic contaminants within the indicator species (Step 3) and a comparison with other taxa within the food web (Step 4). The majority of lakes within the watershed contained seven to nine leech species with individuals of Nephelopsis obscura being one of the most abundant and widely distributed species that is sufficiently large to allow for rapid collection of sufficient biomass for organic contaminant analyses. Concentrations of organic contaminants in leeches from 22 sites and in sediments (two lakes) within the watershed were low, and in the majority of cases less than analytical detection levels (i.e., 0.05 μg/kg wet weight). Nevertheless, leech tissues contained trace amounts of a fungicide (i.e., hexachlorobenzene) and four pesticides including: pp′-DDE, pp′-DDD, representing intermediate and final breakdown products of pp′-DDT, a-HCH (i.e., hexachlorocyclohexane) and g-HCH (Lindane). Concentrations of these contaminants did not differ significantly between leeches collected from lakes within a national park compared to areas outside the park that may have been more vulnerable to loadings of contaminants from industrial and agricultural sources. Lastly, we compared organic contaminant concentrations in N. obscura with Gammarus lacustris and Brook's stickleback, Culaea inconstans (Gasterosteidae). Organic contaminant concentrations in N. obscura were similar or higher than those present in G. lacustris and C. inconstans. Eight organic contaminants were found in N. obscura, whereas, C. inconstans and G. lacustris contained only three and four, respectively. The fact that N. obscura typically contained higher concentrations and greater numbers of detectable compounds suggest that it is a suitable indicator of organic contamination. While current levels of organic contaminants in the Beaver Hills watershed are low, despite the intense agriculture and industrial activities, they should be monitored to act as an early warning indicator of ecosystem degradation.

Sediment Toxicity Evaluation for Hexachlorobenzene: Spiked Sediment Tests with Leptocheirus plumulosus, Hyalella azteca, and Chironomus tentans by P. C. Fuchsman; T. R. Barber; P. J. Sheehan (pp. 573-579).

Hexachlorobenzene (HCB) is a hydrophobic organic chemical that has shown a lack of toxicity in aquatic tests at concentrations up to and exceeding the solubility limit. The equilibrium partitioning approach to deriving sediment quality benchmarks, which assumes that toxicity can be predicted based on contaminant concentrations in interstitial water, predicts that HCB will not produce direct toxicity to benthic invertebrates as a sediment contaminant. However, the potential for toxicity due to direct exposure to sediment-adsorbed HCB has not been thoroughly established. This study evaluated the survival and growth of the estuarine amphipod Leptocheirus plumulosus, the freshwater amphipod Hyalella azteca, and the midge Chironomus tentans (freshwater) following 10-day exposure to sediment spiked with a range of HCB concentrations. H. azteca was tested under both freshwater and estuarine (10 ppt salinity) conditions. No significant toxicity was observed for any test species at the highest test concentration (60 mg/kg normalized to 1% organic carbon). Minimum detectable differences were less than or equal to 20% for three of eight test endpoints. The observed results add to the available weight of evidence indicating a limited potential for HCB-related sediment toxicity to benthic invertebrates.

Environmental Effects of Sodium Acetate/Formate Deicer, Ice Shear™ by S. S. Bang; D. Johnston (pp. 580-587).

The environmental impacts of Ice Shear™, an alternative highway deicer, have been evaluated using standard laboratory tests; biochemical oxygen demand (BOD) tests, chemical oxygen demand (COD) tests, acute rainbow trout bioassays, and phytotoxicity tests were used. Ice Shear consists of equimolar sodium acetate and sodium formate. The organic matter of the deicer can be readily degraded microbiologically in the natural environment with a slow rate of degradation at lower temperatures but an increased rate at higher temperatures. At elevated temperatures, highway runoffs of the deicer may reduce the level of dissolved oxygen in the receiving waters to cause an adverse impact. However, the apparent activation energy calculated for the BOD rate of Ice Shear is low (8.78 kcal mole⁻¹), indicating that the temperature variation may not significantly influence the biodegradation of the deicer compound. Ice Shear appears relatively harmless to aquatic animals, showing a high 96-h LC₅₀ value (16.1 g/L) derived for rainbow trout (Oncorhynchus mykiss). Ice Shear causes minimal toxicity to representative roadside vegetation; herbaceous (e.g., sunflowers, beans, and lettuce) and woody (e.g., pine seedlings) plants. Rather, the deicer at low concentrations (less than 2 g/kg soil) seems to work as a fertilizer, promoting the yield of biomass. The test results indicate that Ice Shear poses minimal environmental disturbance in both aquatic and terrestrial ecosystems.

Interference by Carbohydrate Substrates, Flavonoids, and Monosaccharide Derivatives on Bacterial β-D-Glucuronidase Assays by A. Mariscal; J. Gómez-Aracena; M. C. Varo; J. Fernández-Crehuet (pp. 588-593).

Most commercially available test kits for water and foodstuffs use β-galactosidase activity for coliforms and β-glucuronidase activity for Escherichia coli. We tested the effects on the β-glucuronidase activity of E. coli W3110 of substances usually present in foods and several synthetic pharmaceutical compounds. Thirteen substances were tested: three carbohydrates, four flavonoids, five monosaccharide derivatives, and dimethyl sulphoxide. In a minimum medium without any other carbon source, glucose (0.1 mM), quercetin (0.1 mM), silymarin (10 mg/L), D-gluconic acid (0.01 mM), D-gluconic acid lactone (0.01 mM), isopropyl-β-D-thiogalacto pyranoside (1 mM), p-nitrophenyl β-D-glucuronide (1 mM), and DMSO (1 M) completely inhibited E. coli glucuronidase activity at the above concentrations. However, the following compounds stimulated E. coli glucuronidase activity within the ranges of concentrations shown: glucose (0.0001–0.01 mM), lactose and sucrose (>0.1 mM), D-saccharic acid 1,4 lactone (0.0001–0.1 mM), p-nitrophenyl β-D-glucuronide (0.001–0.01 mM) and DMSO (2–500 mM). In a rich culture medium that contained other carbon sources (lauryl tryptose broth) E. coli glucuronidase activity in the presence of the extra nutrients was unaffected by the test substances and therefore, under normal conditions in water or foods, they should not interfere with E. coli assays based on measurements of β-glucuronidase activity.

Trace Metals and Variations of Antioxidant Enzymes in Arctic Bivalve Populations by F. Regoli; H. Hummel; C. Amiard-Triquet; C. Larroux; A. Sukhotin (pp. 594-601).

In the framework of an INTAS project, arctic populations of the clam Macoma balthica were collected from seven stations (Mezen, Khaypudyr, Pechora 3, Pechora 5, Dvina, Keret 1, and Keret 2) in the White Sea and Pechora Sea. The main objectives of this research were to define baseline concentrations of trace metals (As, Cd, Cr, Cu, Fe, Mn, Pb, Zn) in M. balthica and to evaluate antioxidant responses as biomarkers of anthropogenic stress in these organisms. The antioxidant parameters examined included the levels of glutathione and the activities of several glutathione-dependent and antioxidant enzymes: glyoxalase I and glyoxalase II (EC 4.4.1.5 and EC 3.1.2.6), glutathione S-transferases (EC 2.5.1.18), glutathione reductase (EC 1.6.4.2), glutathione peroxidases (EC1.11.1.9 and EC 2.5.1.18, respectively, for Se-dependent and Se-independent forms), superoxide dismutase (SOD, EC 1.15.1.1), and catalase (EC 1.11.1.6). Organisms revealed enhanced concentrations of lead in both Keret stations, Khaypudyr, and Mezen, and high levels of copper in Keret and cadmium in Khaypudyr. At the biochemical level, organisms from Pechora 3, Pechora 5, and Dvina were not statistically different, whereas those from Mezen and Khaypudyr exhibited higher activities of superoxide dismutase, glutathione peroxidase, and glyoxalase II. Catalase levels were lower in Mezen and Khaypudyr. More heterogeneous were the responses of glyoxalase I and glutathione S-transferases, while no significant differences among the stations were observed for glutathione reductase. Multiple regression analyses revealed significant positive relationships between the main antioxidant enzymes (glutathione peroxidases, superoxide dismutase, glyoxalase I, and glyoxalase II), and confirmed the exception of catalase, which, when significant, was negatively correlated with the other parameters. The results support the suitability of antioxidant responses as biomarkers of pollutant exposure and/or toxicity for arctic biomonitoring programs even though only moderately polluted sites were sampled.

Glutathione, Glutathione-Related Enzymes, and Catalase Activities in the Earthworm Eisenia fetida andrei by M. Saint-Denis; F. Labrot; J. F. Narbonne; D. Ribera (pp. 602-614).

The aim of this work was to provide basic data on the antioxidant defences in the annelid Eisenia fetida andrei (E. f. a.). Methods for measurement of three antioxidant enzymes—catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GR)—and of glutathione-S-transferase (GST) were optimized. GPX activity differed according to the substrate used: cumene hydroperoxide (CUOOH) or hydrogen peroxide (H₂O₂). The effects on the enzyme activities of storage up to 2 months at −80°C, −20°C, and +4°C were evaluated. The subcellular distribution (in cytosol, mitochondrial, and microsomal fractions) was examined. The properties and subcellular distribution of the enzymes and glutathione were also characterized in dissected tissues and body fluids. The GR activity decreased at −80°C and was the only one not stable at this temperature. The four enzymes were localized mainly in the cytosolic fraction. CAT distribution was unusual as it was not associated with peroxisomes, its properties being consistent with a catalase-peroxidase, rather than a true catalase. However, this result could also be an artifact linked to the use of an inappropriate method to obtain the fractions. Our observations indicate the presence of a distinct cytosolic selenium-dependent GPX (Se-GPX), and of a possible microsomal Se-GPX. A strong non–Se-GPX activity was measured in the CF and CL, which could be linked to the peroxidase activity of fetidins secreted by coelomocytes and with the ROS production of these cells. This study seems to indicate that E. f. a. is well equipped for the metabolism of electrophilic and pro-oxidants through glutathione.

Effects of Boron and Nitrate on Hatching Success of Amphibian Eggs by M. M. Laposata; W. A. Dunson (pp. 615-619).

As part of a land-application wastewater disposal system in central Pennsylvania, vernal ponds are commonly exposed to wastewater effluent containing high levels of boron and nitrate. We examined the individual effects of these compounds on the eggs of amphibians breeding in these ponds. Wood frog (Rana sylvatica), Jefferson salamander (Ambystoma jeffersonianum), spotted salamander (A. maculatum), and American toad (Bufo americanus) eggs were exposed to boron (0, 50, and 100 mg L⁻¹) and nitrate (0, 10, 25, and 40 mg L⁻¹) under laboratory conditions. There was no difference in the hatching success or proportion of deformed larvae among the four nitrate levels in any of the species. High boron concentrations reduced the hatching success of B. americanus and produced more deformed offspring in R. sylvatica, A. jeffersonianum, and A. maculatum. Deformed R. sylvatica and A. jeffersonianum hatchlings displayed a “curling defect” in which the larvae had a crescent body shape and expressed difficulty in swimming. A. maculatum larvae from high boron treatments displayed a different abnormality, possibly because of longer times to hatching, characterized by a swelling of the thoracic region and altered gill morphology. Although the concentrations of boron and nitrate tested were within the range measured in wastewater effluent, maximum levels of boron and nitrate in breeding ponds were only 1.5 mg L⁻¹ and 26.7 mg L⁻¹ respectively, likely due to rainwater dilution and biological and chemical processes reducing the levels of these compounds in vernal ponds. Nonetheless, these studies are the first to examine the effects of boron and nitrate on amphibian egg hatching success, and to demonstrate that elevated boron concentrations can detrimentally affect the development of amphibian embryos.

Contaminants in Ospreys from the Pacific Northwest: I. Trends and Patterns in Polychlorinated Dibenzo-p-Dioxins and -Dibenzofurans in Eggs and Plasma by J. E. Elliott; M. M. Machmer; C. J. Henny; L. K. Wilson; R. J. Norstrom (pp. 620-631).

Osprey (Pandion haliaetus) eggs were collected from 1991 to 1997 at nests (n = 121) upstream and downstream of bleached kraft pulp mills and at reference sites in the Fraser and Columbia River drainage systems of British Columbia, Washington, and Oregon. Blood samples were collected from nestling ospreys during the 1992 breeding season on the Thompson River. Samples were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs) and -dibenzofurans (PCDFs). Mean concentrations of 2,3,7,8-TCDD were significantly higher in eggs collected in 1991 at downstream compared to upstream nests near pulp mills at Kamloops and Castlegar, British Columbia. There were no significant temporal trends in 2,3,7,8-TCDD, -TCDF or other measured compounds at a sample of nests monitored between 1991 and 1994 downstream of the Castlegar pulp mill, despite changes in bleaching technology (CIO₂ substitution). However, by 1997 concentrations of 2,3,7,8-TCDD and -TCDF were significantly lower than previous years in nests sampled downstream at both Castlegar and Kamloops. An unusual pattern of higher chlorinated PCDDs and PCDFs was found in many of the osprey eggs collected in this study, and considerable individual variation in the pattern existed among eggs from the same site. For example, eggs from four different nests at one study area (Quesnel) on the Fraser River had concentrations of 1,2,3,4,6,7,8-HpCDD ranging from <1 to 1,100 ng/kg and OCDD from <1 to 7,000 ng/kg wet weight. Higher mean concentrations of HpCDD and OCDD were found in eggs from the Thompson River, a tributary of the Fraser, compared to the Columbia River, and concentrations were generally higher at nests upstream of pulp mills. In plasma samples, 1,2,3,4,6,7,8-HpCDD and OCDD were the main compounds detected, with no significant differences measured between samples upstream versus downstream or earlier versus later in the breeding season. Use of chlorophenolic wood preservatives by lumber processors was considered the main source of higher chlorinated PCDD/Fs throughout the systems, based on patterns of trace PCDFs in eggs and significant correlations between egg concentrations of pentachlorophenol and both HpCDD (r = 0.891, p < 0.01) and OCDD (r = 0.870, p < 0.01).

Influence of Heavy Metal Exposure During Different Phases of the Ontogeny on the Development of Pied Flycatchers, Ficedula hypoleuca, in Natural Populations by N. E. I. Nyholm (pp. 632-637).

Distribution of 14 Elements in Tissues and Organs of Oceanic Seabirds by E. Y. Kim; R. Goto; S. Tanabe; H. Tanaka; R. Tatsukawa (pp. 638-645).

The concentrations of 14 trace elements (Li, V, Mn, Co, Cu, Zn, Se, Rb, Sr, Ag, Cd, Cs, Pb, and Hg) were determined in tissues and organs of three species and in the liver of 11 species of seabirds. Comparatively high concentrations of Li, Co, Sr, and V were found in the femur. Cd, Se, Cu, and Mn concentrations were relatively higher in the kidney than in other tissues and organs. Rb, Cs, and Pb concentrations were rather uniform among tissues. Concentrations of essential elements such as Mn, Cu, and Co were comparable among seabird species, except high Cu concentrations in northern giant petrel. Among nonessential elements, concentrations of Cd and Hg were variable according to seabird species. Pb levels were low in all the species. High Se levels (100 μg/g dry weight) were found in the liver of black-footed albatross and grey petrel. There were significant positive correlations between Se and Cd concentrations in three species and between Se and Hg in black-footed albatross, suggesting that Se has an antagonistic action on the toxic effects of Cd and Hg. Concentrations of Li, V, Ag, and Cs were usually low (less than 1 μg/g dry weight).

Lack of Developmental and Reproductive Toxicity of 2,3,3′,4,4′-Pentachlorobiphenyl (PCB 105) in Ring-Necked Pheasants by M. W. Hornung; L. Miller; B. Goodman; M. J. Melancon; R. E. Peterson (pp. 646-653).

Mono-ortho PCBs are global contaminants of wildlife with the potential to produce toxicity by an aryl hydrocarbon receptor (AhR)–mediated mechanism. To determine the potency of 2,3,3′,4,4′-pentachlorobiphenyl (PCB 105) for producing reproductive and developmental toxicity, adult ring-necked pheasant hens (Phasianus colchicus) were orally dosed with 0, 0.06, 0.6, or 6 mg PCB 105/kg hen/week for 10 weeks to achieve cumulative doses of 0, 0.6, 6, or 60 mg PCB 105/kg hen after which hens were bred with untreated roosters once per week for 8 weeks. Except at week 6 of the egg-laying period when cumulative egg production in the 6 mg PCB 105/kg hen group was greater than controls, fertilized egg production was not significantly different between treatment groups. Embryo mortality and chick mortality were not significantly different between treatment groups. Total body and heart weights of all chicks 1 day posthatch (dph) were not different between groups, however, liver weights of chicks from the 60 mg/kg treatment group were greater than controls at 1 dph. The first chick to hatch from each hen was reared to 21 dph and among these birds, the total body, liver, and heart weights were not different between groups. There were no dose-related malformations of the beak or limbs, and no signs of subcutaneous edema, ascites, or pericardial edema in chicks at 1 or 21 dph. Hepatic microsomal monooxygenase activities [ethoxyresorufin-O-dealkylase (EROD), benzyloxyresorufin-O-dealkylase (BROD), and methyloxyresorufin-O-dealkylase (MROD)] were significantly elevated in chicks at 1 dph from hens given a cumulative PCB 105 dose of 6 mg/kg and in chicks at 21 dph from hens given a cumulative PCB dose of 60 mg/kg. These results indicate that a cumulative PCB 105 dose up to 60 mg/kg hen does not decrease the production of fertilized eggs or increase embryo or chick mortality in ring-necked pheasants, but does increase chick hepatic monooxygenase activity.

Studies of Bioaccumulation and Biotransformation of PCBs in Mustelids Based on Concentration and Congener Patterns in Predators and Preys by P. E. G. Leonards; S. Broekhuizen; P. de Voogt; N. M. Van Straalen; U. A.Th. Brinkman; W. P. Cofino; B. van Hattum (pp. 654-665).

Bioaccumulation of non-, mono-, and di-ortho–substituted chlorobiphenyls (CBs) was investigated in four species of mustelids (weasel, stoat, polecat, and otter) and their preys, from a restricted area in the northern part of The Netherlands. Diets of these mustelids ranged from terrestrial (weasel, stoat, and polecat) to aquatic (otter). Diet-specific biomagnification factors (BMFs), CB in diet relative to CB in mustelids, were calculated for the sum of 28 congeners (ΣCB), for the sum of the toxic equivalent concentration (ΣTEQ) and on an individual congener basis. Biotransformation was studied in relation to structural CB properties (vicinal H-atom substitution). In addition, the methylsulphonyl CB-metabolites were determined. The concentration of ΣCB on lipid weight basis increased in the order weasel < stoat < polecat < otter. On the basis of ΣTEQ, the order changed to weasel < polecat < stoat < otter. Most of the differences in BMFs between the CBs could be explained by the vicinal H-atom structure-activity rules. For all mustelids, the lowest BMFs were found for congeners with vicinal H-atoms in the meta, para position. Indications were found that all mustelid species can metabolize these congeners. For some of the CBs, their methylsulphonyl-CB metabolites were determined and found to be present in concentrations up to 350-fold higher than those of the parent compounds. In addition, the non-ortho CBs 126 and 169 are selectively retained in the liver of weasel, stoat, and otter. These CBs had the highest BMFs of all congeners. However, rather surprisingly, in polecat the highest BMFs were found for di-ortho–substituted CBs. This animal was able to metabolize all congeners with vicinal H-atoms in the ortho and meta position (non- and mono-ortho CBs). The information concerning the differences in bioaccumulation of CBs for closely related mustelid species increased the understanding of reported differences in PCB toxicity between mink and ferrets, and suggest that weasel, stoat, and otter are at least as sensitive to CBs as are mink, while polecats are less sensitive. As otter is exposed to much higher concentrations of CBs trough their diet than weasel and stoat, the toxic threat of CBs will be the greatest for this animal.

Species and Organ Dependence of PCB Contamination in Fish, Foxes, Roe Deer, and Humans by G. Bachour; K. Failing; S. Georgii; I. Elmadfa; H. Brunn (pp. 666-673).

According to previous experimental results, PCBs are deposited in muscle fat in animals and in humans, although they also reach the brain, the liver, and the lungs. The aim of the present study was to determine the concentrations of the so-called “indicator PCBs” (PCB nos. 28, 52, 101, 138, 153, 180), as described by the German ordinance for maximum concentrations of contaminants in foodstuffs, in muscle tissue, liver, and brain of four different species: fish, fox, roe deer, and humans, all exposed to PCBs directly in their environment. Potential target organs for the accumulation of these congeners were also to be identified. Furthermore, the organs or tissues were to be identified in which PCBs are accumulated, and unusual patterns of accumulation or breakdown of particular PCBs, for example the “dioxin-like PCBs” (coplanar PCBs) determined. For humans, the lungs were also included in these studies. Statistical comparison of PCB concentrations in samples from wild animals and humans showed that in spite of its relatively high fat concentration, brain tissue in all of the species examined (with the exception of fish) appeared to be better protected against accumulation of PCB than liver or muscle tissue. This protection may be the result of the blood-brain barrier, as witnessed by the relatively uniform concentration of PCBs throughout the various organs of fish, since the blood-brain barrier of fish is considerably less efficient than that of mammals. No peculiarities were found in regard to distribution of the coplanar PCBs over the other congeners in this study. This applies to the brain and other organs or tissues of the four species that were examined. Accumulations of PCBs and coplanar PCBs in the liver were only found in fox and roe deer. In contrast, humans were found to have accumulations of the high-chlorinated biphenyls studied here as well as PCB no. 118 in muscle tissue fat and not in the liver. Unexpectedly, low-chlorinated biphenyls were found to accumulate in the human lung. The results of this study show that the lung represents a target organ for the accumulation of potentially metabolically activated low-chlorinated biphenyls, indicating that the possible biological effects of PCBs on the lungs will need to receive more attention in the future.

Hexachlorocyclohexane and Its Isomers: Regional Brain Levels in the Rat After Dermal Exposure by R. Kumar; N. Pant; S. P. Srivastava (pp. 674-679).

In the present study the distribution of hexachlorocyclohexane (HCH) and its isomers in the brain of rats given dermal exposure of this pesticide have been investigated using a gas liquid chromatographic technique. The male Druckery rats were given dermal exposure of HCH 50 or 100 mg/kg body weight/day in 0.2 ml acetone for the period of 60 or 120 days. The results reveal that an appreciable quantity of HCH and its isomers alpha, beta, gamma, and delta accumulate in a dose- and time-dependent manner in different regions of the brain, which may adversely affect the specific physiological function of these brain regions.

Bioavailability of PCBs to Male Laboratory Rats Maintained on Litters of Contaminated Soils: PCB Burden and Induction of Alkoxyresorufin O-Dealkylase Activities in Liver and Lung by M. O. Fouchécourt; P. Berny; J. L. Rivière (pp. 680-687).

Male rats from the Sprague-Dawley laboratory strain were maintained in the laboratory during 3 days and 1 night on litters containing a reference soil and different amounts of a soil, mainly polluted by PCBs (207 ppm expressed in Aroclor® 1254; SIII soil). Two categories of biomarkers of exposure were measured in both liver and lung of these rats: PCB burdens and activities of microsomal liver and lung cytochrome P450–dependent mono-oxygenases, namely ethoxy-, pentoxy-, and benzoxy-resorufin O-dealkylase activities (EROD, PROD, and BROD, respectively). PCB burdens in liver and lung of rats exposed to SIII soil were 1,845 and 241 ppb, respectively (expressed in Aroclor® 1254 equivalents). EROD, PROD, and BROD were significantly induced in the liver of rats exposed to SIII soil, while only EROD activity was induced in the lung. Induction of hepatic EROD activity was ∼3- to 5.4-fold; pulmonary EROD activity was induced by 9- to 12-fold. In the lung, PROD and BROD activities were inhibited. When rats were exposed to SIII soil diluted with various amounts of standard ISO soil, a nearly linear dose-response relationship was found between the level of PCBs in the litter and EROD activity in both liver and lung. A nonlinear dose-response relationship exists with hepatic BROD activity; no dose-response relationship was observed with hepatic PROD and pulmonary PROD and BROD activities. EROD activity measurement in both liver and lung of rats maintained on a litter of PCB polluted soil was used to assess the bioavailability to mammals of PCBs.

Technical Hexachlorocyclohexane Use Trends in China and Their Impact on the Environment by Y. F. Li; D. J. Cai; A. Singh (pp. 688-697).

Trends in production of technical HCH (BHC: 1,2,3,4,5,6-hexachlorocyclohexane) in China have been surveyed from 1952 to 1983, when the Chinese government banned the use of this pesticide. While the total 4.46 million metric tons produced during this period make China by far the biggest producer and user of technical HCH, Japan consumed the largest accumulated average amount of this insecticide over arable land (84 t/kha for Japan versus 44 t/kha for China). The relationship between technical HCH production/usage trends and their impact on the environment has been studied. The similarity between total HCH isomer concentrations in Chinese environmental compartments in the beginning of 1980s and those in Japanese in the beginning of 1970s indicates the linkage between the average accumulated usage of technical HCH and the magnitude of contamination in the environment by this organochlorine insecticide. According to data from a national monitoring program on food contamination by organochlorine pesticides, residues of total HCH in foodstuffs in China decreased by about five times in rice, 127 times in fish, 32 times in poultry eggs, and 32 times in meat between 1978 and 1992.

Efficiency of Safety Measures Applied to a Manual Knapsack Sprayer for Paraquat Application to Maize (Zea mays L.) by J. G. Machado-Neto; T. Matuo; Y. K. Matuo (pp. 698-701).

The objectives of the present study were to evaluate the safety of mixer/loaders and applicators of paraquat to maize crop by knapsack sprayers and to determine the efficacy of safety measures applied to the sprayers. Potential dermal exposure (PDE) was evaluated in 22 worker body parts. The Cu²⁺ cation of a copper-based fungicide was used as tracer in the spray solution. Sanitary pads and cotton gloves were used to collect the pesticide solution on the sampled body parts. It was observed that paraquat application in front of the applicator's body (0.5 and 1.0 m lance) is unsafe because PDE was 1,979.8 ml/day (for 0.5 m lance) and 1,290.4 ml/day (for 1.0 m lance) and needs 50–80% and 37–69% control of PDE respectively. Control can be achieved by the use of protective garment on the legs and feet only, which received 92–93% of the PDE. Switching the spray nozzle to the back of the operator reduced the PDE by 98% and was sufficient to make working conditions safe, while maintaining the efficiency of application and making the work lighter and more comfortable. Mixer/loaders received 86% of the PDE to the hands and the work condition was safe (MOS > 1), however impermeable gloves could be used as a further safety measure.

Twenty-Five Years of Surveillance for Contaminants in Human Breast Milk by A. G. Craan; D. A. Haines (pp. 702-710).

To monitor the exposure of Canadian populations, Health Canada has carried out six major surveys of breast milk contaminants, beginning in 1967. In these national surveys, breast milk was collected from nursing mothers at various times in their nursing period, and the concentrations of chlorinated hydrocarbons were measured. There was a downward trend from 1967 to 1992, in the concentrations of organochlorine (OC) pesticides and polychorinated biphenyl hydrocarbons (PCBs). This regression was observed for samples across Canada, except for a sharp isolated increase in 1982 for the Quebec Province. As the disappearance curves of the chemicals surveyed follow the same pattern for both Ontario and Canada, a similar decline could be expected of OC concentrations in human breast milk in the Great Lakes Basin.

Estimation of Target Hazard Quotients and Potential Health Risks for Metals by Consumption of Seafood in Taiwan by B.-C. Han; W. L. Jeng; R. Y. Chen; G. T. Fang; T. C. Hung; R. J. Tseng (pp. 711-720).

The purpose of this paper is to describe the impact of metal pollution on the main seafood and assess the potential health risk from consuming the contaminated seafood in Taiwan. The results of geometric mean (GM) metal concentrations in various seafood showed that the copper, zinc, and arsenic concentrations in oysters were significantly (p < 0.001) higher than those in the other seafood by about 1,057, 74.3, and 56.2 times, respectively. The green color found in the oysters was due to high GM copper and zinc concentrations of 909 (ranging from 113–2,805) and 1,293 (ranging from 303–3,593) μg/g dry wt, respectively. In addition, using a maximum consumption rate of 139 g/day of oysters for individuals, calculations yield target hazard quotients (daily intake/reference dose) of below 1 for cadmium and mercury and high values of 1.61, 9.33, and 1.77 for inorganic arsenic, copper, and zinc in adults, respectively. The various lifetime cancer risks for inorganic arsenic (maximum exposed individuals risk ranging from 9.93 × 10⁻⁶ to 3.11 × 10⁻⁴) might be caused by consuming different seafood in Taiwan. The highest risk estimate for inorganic arsenic was 5.10 × 10⁻⁴ for consumption of oysters by Machu Islands residents. The long-term exposure of metals through consumption of oysters, especially for some high-risk groups, could be dangerous. Taking inorganic arsenic for example, a 10⁻⁶ upper limit on lifetime risk as the health protection standard would require maximum oyster residue levels of approximately 0.0076–0.056 μg/g wet wt, for consumption rates of 139–18.6 g/d. In the light of known risks to public health, the government should issue an immediate warning to the public to refrain from eating all seafood harvested from the Taiwan coastal areas, especially the Hsiangshan area and the Machu Islands.

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Archives of Environmental Contamination and Toxicology (v.35, #4)

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Archives of Environmental Contamination and Toxicology (v.35, #4)