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Archives of Environmental Contamination and Toxicology (v.57, #3)
Application of Tryptophan Fluorescence to Assess Sensitizing Potentials of Chemicals by Thi-Thu-Phuong Pham; Tsunehiro Oyama; Toyohi Isse; Toshihiro Kawamoto (pp. 427-436).
There are too many chemical substances around our living space. However, the toxicity of most of them has not been reported, especially regarding their sensitizing potentials. We aimed to develop a simple in vitro method to quantitatively predict the sensitizing potentials of chemicals by measuring the fluorescence of chemical-human serum albumin (HSA) complexes. HSA was treated with test chemicals and then analyzed by tryptophan fluorescence and protein concentration measurement. Four commonly designated sensitizers, two possible sensitizers, and two nonsensitizers were examined using the tryptophan fluorescence assay. HSA fluorescence at 280 nm excitation and 340 nm emission was reduced by toluene 2,4-diisocyanate (TDI), dose dependently. The addition of TDI immediately reduced the fluorescence, and it was stable for 6 h to 21 days after treatment, with a slight decrease. The reduction of HSA fluorescence by chemicals was in the order: commonly designated sensitizers > possible sensitizers > nonsensitizers. Chemical treatment at 0.05 and 0.5 mM led to optimal separation among the three groups. o-Phthalaldehyde (OPA), which has not been evaluated regarding its sensitization potential by any of the authorized organizations, reduced HSA fluorescence as much as the commonly designated sensitizer at final concentrations of the chemical of 0.05 and 0.5 mM. According to our method, OPA is evaluated as a commonly designated sensitizer. The treatment of all test chemicals did not lead to marked differences in the total protein concentrations by either the Lowry or the Bradford method. The assay utilizing tryptophan fluorescence loss of HSA after chemical treatment is a promising method to evaluate the sensitizing potentials of chemicals.
Polychlorinated Biphenyls in the Atmosphere of an Urban City: Levels, Distribution, and Emissions by Laiguo Chen; Xiaochun Peng; Yumei Huang; Zhencheng Xu; Bixian Mai; Guoying Sheng; Jiamo Fu; Xinhua Wang (pp. 437-446).
Polychlorinated biphenyl (PCB) concentrations, profiles, and possible sources were determined in the atmosphere of Guangzhou, the largest city in south China. ∑PCB concentrations ranged from 160 to 2720 pg/m3, which is comparable with values found by similar studies in North America, Europe, and Asia. The highest PCB concentrations were found in the old industrial district, suggesting it to be the principal emission source. The most important PCB homologue group was tetra-PCB, followed by tri- and penta-PCB. The PCBs’ homologue composition differs from that found in Chinese transformer oils: Chinese PCB products (no. 1 PCB and no. 2 PCB), Aroclor1242, and Aroclor1254. However, it is similar in composition to that found in sediments and soils subjected to arbitrary disposal of used electronic appliances in this region. Our results suggest that volatilization from PCB-contaminated soils in the old urban center may be the major source of PCBs in the atmosphere of Guangzhou. Additional studies will be required to characterize the geochemical cycles of PCBs from the contaminated environmental “hot spots” during the typical subtropical climate conditions in the study regions.
Comparison of Organochlorine Pesticides Occurrence, Origin, and Character in Agricultural and Industrial Soils in Beijing by Yajuan Shi; Yonglong Lu; Tieyu Wang; Guang Wang; Wei Luo (pp. 447-455).
The origin and occurrence of organochlorine pesticides [OCPs; hexachlorocyclohexanes (HCHs) and 1,1,1-trichloro-2,2- bis(p-chlorophenyl) ethane (DDTs)] in the surface and profile of soils from former OCPs production areas were compared with those of agricultural plots in Beijing, China in order to identify their characteristics, assess the eco-toxicological risk, and provide management suggestions. The comparison indicated heavier contamination caused by the production, storage, and waste disposal than the application of OCPs. Concentrations of HCHs and DDTs in topsoils varied by several orders of magnitude among different land-use groups. The concentrations (ng/g dry soil, geometric means) of HCHs (1958.2) and DDTs (3998.2) in the topsoils of former OCPs production factories were significantly higher than those in agricultural soils. The residue of DDTs and HCHs accumulated only on the surface of agricultural soil, but at depths ranging from 0 to 400 cm for the OCPs plant and warehouse. β-HCH and p,p’-DDE dominated in the agricultural soils, whereas β-HCH, γ-HCH, p,p’-DDT, and p,p’-DDE were dominant in the industrial soils. The risk of examined OCPs in soils on human health was assessed in light of the Dutch and Canadian soil quality criteria, and the results indicated a high risk in the OCPs production factory area and the agricultural lands with large application. The results point to the need for urgent actions to evaluate long-term toxicity and preassessment for OCPs-related land-use management.
Antioxidant Enzyme Activity in Bacterial Resistance to Nicotine Toxicity by Reactive Oxygen Species by Tiejuan Shao; Haiping Yuan; Bo Yan; Zhenmei Lü; Hang Min (pp. 456-462).
We analyzed superoxide dismutase (SOD), catalase (CAT), and ATPase activities in the highly nicotine-degrading strain Pseudomonas sp. HF-1 and two standard strains Escherichia coli and Bacillus subtilis in an attempt to understand antioxidant enzymes in bacteria are produced in response to nicotine, which increases the virulence of the bacteria. Nicotine had different effects on different antioxidant enzymes of different bacteria. SOD plays a more important role in resistance to nicotine stress in E. coli than it does in CAT. Multiple antioxidant enzymes are involved in combating oxidative stress caused by nicotine in Pseudomonas sp. HF-1. The contribution of a particular antioxidant enzyme for protection from nicotine stress varies with the growth phase involved. The inhibition of ATPase in Pseudomonas sp. HF-1 at the stationary phase was enhanced with increasing nicotine concentration, showing a striking dose–response relationship. Nicotine probably affected the metabolism of ATP to some extent. Furthermore, different bacteria possessed distinct SOD isoforms to cope with oxidative stress caused by nicotine.
Genotoxic and Mutagenic Potential of Agricultural Soil Irrigated with Tannery Effluents at Jajmau (Kanpur), India by Mohammad Zubair Alam; Shamim Ahmad; Abdul Malik (pp. 463-476).
It is a common practice in India to irrigate agricultural fields with wastewater originating from industries and domestic sources. At Jajmau (Kanpur), India, tannery effluent is used for irrigation purposes. This practice has been polluting the soil directly and groundwater and food crops indirectly. This study is aimed at evaluating the mutagenic impact of soil irrigated with tannery effluent. Soil extracts were prepared using four organic solvents (dichloromethane, methanol, acetonitrile, and acetone) and tested with Ames Salmonella/microsome test and DNA repair-defective E. coli k-12 mutants. Gas Chromatography-mass spectrometric analysis of soil samples revealed the presence of a large number of organic compounds including bis(2-ethylhexyl)phthalate, benzene, 1,3-hexadien-5-yne, 2,4-bis(1,1-dimethyl)phenol, Docosane, 10-methylnonadecane, and many higher alkanes. The soil extracts exhibited significant mutagenicity with Ames tester strains. TA98 was found to be the most sensitive strains to all the soil extracts, producing maximum response in terms of mutagenic index of 14.2 (–S9) and 13.6 (+S9) in the presence of dichloromethane extract. Dichloromethane-extracted soil exhibited a maximum mutagenic potential of 17.3 (–S9) and 20.0 (+S9) revertants/mg soil equivalent in TA100. Methanol, acetonitrile, and acetone extracts were also found to be mutagenic. A significant decline in the survival of DNA repair-defective E. coli K-12 mutants was observed compared to their isogenic wild-type counterparts when treated with different soil extracts. PolA mutant was found to be the most sensitive strain toward all four soil extracts.
Effect of pH, EDTA, and Anions on Heavy Metal Toxicity Toward a Bioluminescent Cyanobacterial Bioreporter by Ismael Rodea-Palomares; Coral González-García; Francisco Leganés; Francisca Fernández-Piñas (pp. 477-487).
The bioavailability and therefore toxicity of a metal depends on the chemical species present in a particular environment. We evaluated the effect of a series of factors that could potentially modify metal speciation on the toxicity of Hg, Cu, Zn, and Cd toward a recombinant strain of the freshwater cyanobacterium Anabaena sp. PCC 7120 with cloned lux operon of luminescent terrestrial bacterium Photorhabdus luminescens. The strain, denoted as Anabaena CPB4337, showed a high constitutive luminescence with no need to add exogenous aldehyde. The tested factors were pH, EDTA (as organic ligand), and anions PO4 3–, CO3 2–, and Cl–. Chemical modeling and correlation analyses were used to predict metal speciation and link it with toxicity. In general, metal toxicity significantly correlated to the predicted metal free-ion concentration, although Zn–EDTA complexes and certain Hg chloro-complexes could also exhibit some toxicity to cyanobacteria. An interesting feature of metal toxicity to strain Anabaena CPB4337 was that low amounts of PO4 3– and CO3 2– increased metal toxicity; this effect could not be related to significant changes in metal speciation and could be attributed to a modulating effect of these anions on metal/uptake toxicity. The combination of toxicity studies that take into account a range of factors that might modulate metal toxicity with chemical modeling to predict changes in metal speciation might be useful for interpreting complex toxicity data. Finally, this cyanobacterial bioreporter, due to its ecological relevance as a primary producer, could be used as a tool for toxicity assessment in freshwater environments.
Use of Sugar Cane Vinasse to Mitigate Aluminum Toxicity to Saccharomyces cerevisiae by Ricardo Pinheiro de Souza Oliveira; Beatriz Rivas Torres; Mario Zilli; Daniela de Araújo Viana Marques; Luiz Carlos Basso; Attilio Converti (pp. 488-494).
Owing to its toxicity, aluminum (Al), which is one of the most abundant metals, inhibits the productivity of many cultures and affects the microbial metabolism. The aim of this work was to investigate the capacity of sugar cane vinasse to mitigate the adverse effects of Al on cell growth, viability, and budding, as the likely result of possible chelating action. For this purpose, Fleischmann’s yeast (Saccharomyces cerevisiae) was used in growth tests performed in 125-mL Erlenmeyer flasks containing 30 mL of YED medium (5.0 g/L yeast extract plus 20 g/L glucose) supplemented with the selected amounts of either vinasse or Al in the form of AlCl3 · H2O. Without vinasse, the addition of increasing levels of Al up to 54 mg/L reduced the specific growth rate by 18%, whereas no significant reduction was observed in its presence. The toxic effect of Al on S. cerevisiae growth and the mitigating effect of sugar cane vinasse were quantified by the exponential model of Ciftci et al. (Biotechnol Bioeng 25:2007–2023, 1983). The cell viability decreased from 97.7% at the start to 84.0% at the end of runs without vinasse and to 92.3% with vinasse. On the other hand, the cell budding increased from 7.62% at the start to 8.84% at the end of runs without vinasse and to 17.8% with vinasse. These results demonstrate the ability of this raw material to stimulate cell growth and mitigate the toxic effect of Al.
Agricultural Pesticides in Mississippi Delta Oxbow Lake Sediments During Autumn and Their Effects on Hyalella azteca by Richard E. Lizotte Jr.; Scott S. Knight; Charles T. Bryant; Sammie Smith Jr. (pp. 495-503).
Agricultural pesticide contamination of sediments from five Mississippi Delta oxbow lakes and their effects and bioavailablity to Hyalella azteca were assessed during a low-application season—autumn. Three reference oxbow lakes were located in the White River National Wildlife Refuge (WRNWR), Arkansas and two impaired lakes, according to the US Environmental Agency Sect. 303 (d) Clean Water Act, were located in Mississippi. Surface sediment (top 5 cm) was collected at three sites within each lake and analyzed for 17 current and historic-use pesticides and metabolites. Chronic 28-day H. azteca sediment bioassays and pesticide body residue analyses were completed to determine the degree of biological responses and bioavailability. The greatest number of detectable pesticides in WRNWR and 303 (d) sediment samples was 9 and 12, respectively, with historic-use pesticide metabolite, p,p′-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] ubiquitous. No significant (p > 0.05) differences in animal survival were observed among sites. Animal growth was significantly (p < 0.05) less at only one site in a 303 (d)-listed lake (Macon Lake). Only six pesticides were observed in H. azteca with current-use pesticides detected at three sites; historic-use pesticides and metabolites detected at 11 sites. Animal body residues of a historic-use pesticide (dieldrin) and metabolite (p,p′-DDE) were associated with observed growth responses. Results show limited current-use pesticide contamination of sediments and H. azteca body tissues during autumn and that historic-use pesticides and metabolites are the primary contributors to observed biological responses.
Identification and Characterization of Freshwater Algae from a Pollution Gradient Using rbcL Sequencing and Toxicity Testing by Phil M. Novis; Cornelia Halle; Belinda Wilson; Louis A. Tremblay (pp. 504-514).
One approach in toxicity testing using microalgae is to assess the modulation of light energy absorbed as a result of exposure to contaminants. In this study, four strains of microalgae were isolated to obtain a variety of taxa for testing from sites receiving various levels of environmental stressors around Christchurch, New Zealand. The strains were characterized by partially sequencing rbcL, a routinely used gene in plant phylogenetics with a large existing database of strains. Based on morphological observation and gene sequences, the strains were identified as Chlorella sp., Neochloris sp., and Choricystis minor. The isolates were exposed to the herbicide glyphosate and the metal zinc, and their responses were measured using the ToxY-PAM system. Chlorella sp. was the most sensitive. Two strains of Choricystis minor were isolated from different ponds in an effluent gradient at a sewage treatment plant. Analysis of variance indicated that the isolate from the least contaminated pond was more sensitive to zinc (although regression analysis did not show this result). This suggests that the selective pressure exerted on algal strains by a contamination gradient over short a distance is detectable by both genetic and physiological methods, with implications for sourcing appropriate indicator organisms from the environment.
Growth and Elemental Accumulation of Plants Grown in Acidic Soil Amended With Coal Fly Ash–Sewage Sludge Co-compost by Jonathan W. C. Wong; Ammaiyappan Selvam (pp. 515-523).
A greenhouse experiment was conducted to evaluate the growth and heavy-metal accumulation of Brassica chinensis and Agropyron elongatum in 10 and 25% ash–sludge co-compost (ASC)—amended loamy acidic soil (pH 4.51) at two different application rates: 20% and 40% (v/v). Soil pH increased, whereas electrical conductivity decreased with the amendment of ASC to soil. Bioavailable Cu, Zn, and Mn contents of ASC-amended soil decreased, whereas Ni, Pb, and B contents increased. Concentrations of bioavailable Cu, Zn, and Mn in sludge compost (SC)–amended soils were 5.57, 20.8, and 8.19 mg kg−1, respectively. These concentrations were significantly lower than those in soil receiving an application rate of 20 or 25% ASC as 2.64, 8.48, and 5.26 mg kg−1, respectively. Heavy metals and B contents of the composting mass significantly increased with an increase in ASC application rate from 20 to 40% (6.2 to 16.6 mg kg−1 for 10% ASC- and 9.4 to 18.6 mg kg−1 for 25% ASC-amended soil. However, when the ash content in co-compost increased from 10 to 25% during composting, bioavailable heavy-metal contents decreased. However, B contents increased with an increase in ash content. Addition of co-composts increased the dry-weight yield of the plants, and this increase was more obvious as the ash amendment rate in the co-composts and the ASC application rate increased. In case of B. chinensis, the biomass of 2.84 g/plant for 40% application of 25% ASC was significantly higher than SC (0.352 g/plant), which was 40% application of 10% ASC (0.434 g/plant) treatments. However, in A. elongatum, the differences between biomass of plants grown with 10% (1.34–1.94 g/ plant) and 25% ASC (2.12–2.21 g/plant) were not significantly different. Furthermore, there were fewer plant-available heavy metals in 25% ASC, which decreased the uptake of heavy metals by plants. ASC was favorable in increasing the growth of B. chinensis and A. elongatum. The optimal ash amendment to the sludge composting and ASC application rates were at 25 and 20%, respectively.
Cadmium Toxicity and Uptake by Mats of the Freshwater Diatom: Navicula pelliculosa (Bréb) Hilse by Elaine C. Irving; Donald J. Baird; Joseph M. Culp (pp. 524-530).
Contaminant uptake by algae, and its subsequent toxicity, has important ramifications for aquatic biomonitoring and environmental risk assessment. To study the effects of cadmium on diatom mats, a series of experiments was undertaken. These investigated the sensitivity of Navicula pelliculosa mats to cadmium, uptake of cadmium across a range of exposure concentrations, influence of mat biomass and thickness on uptake, and cadmium uptake by mats over time. Diatom mat formation proved to be sensitive to cadmium exposure, with a 96-h EC50 of 31 μg/L. The rapid uptake of cadmium over 15 min was a linear function of exposure concentration and was not significantly affected by mat thickness. Cadmium uptake over time was also a linear function of exposure concentration for time periods up to 5 h. Linear uptake was likely due to the availability of algal binding sites as cadmium ions diffused through the diatom mats. Internal high-pH microenvironments may also have influenced uptake, through cadmium precipitation or enhanced adsorption within the mats. The lack of a significant relationship between mat biomass and uptake could be explained by the static water exposure conditions. Other studies have shown that cadmium uptake by algal mats was only significantly affected by biomass under flowing water conditions. Flowing water appeared to facilitate the diffusion of cadmium ions through the algal mats. Our research demonstrates the propensity of diatom mats to adsorb cadmium to achieve concentrations that could inhibit macroinvertebrate grazing. Overall, these findings contribute to a greater understanding of cadmium bioavailability in aquatic ecosystems and to the further development of benthic algae as an effective biomonitoring tool.
Accumulation and Chronic Toxicity of Uranium Over Different Life Stages of the Aquatic Invertebrate Chironomus tentans by Jorgelina R. Muscatello; Karsten Liber (pp. 531-539).
Limited data are available on the effects of uranium (U) exposures on benthic macroinvertebrates, something that would be needed before national or provincial water quality guidelines could be developed. The goal of this study was to evaluate chronic U toxicity and accumulation in the aquatic invertebrate Chironomus tentans. Test organisms were exposed to three aqueous U concentrations (40, 200, and 1,000 μg/L) and an untreated control. Larval growth, adult emergence, and U tissue concentrations at different life stages were evaluated. The measured no-observed-effect concentration (NOEC) and lowest-observed-effect concentration (LOEC) for growth of C. tentans larvae after 10 days of U exposure were 39 and 157 μg/L, respectively. At U concentrations >157 ug/L, there was reduced larval growth of 30% to 40%, which corresponded to reduced adult emergence of 40% to 60%. Despite significant delays in time to adult emergence, there were no significant effects on reproductive output of successfully emerged adults. The F1 generation C. tentans larvae that were never directly exposed to U, but originated from adult males and females exposed to U during their immature life stages, displayed a significant decrease in 10-day growth that was similar to that observed for the F0-exposed larvae. This suggests that the environment of the parental generation can significantly influence the development of the next generation through environmentally induced parental effects. Uranium accumulated in C. tentans immature stages was partially excreted during molting and metamorphosis to the adult stage. However, the elimination of U was not complete and some was still measured in adult midges. Consequently, a minor transfer of U from the aquatic to the terrestrial environment could be expected to occur.
Assessment of the Environmental Quality of French Continental Mediterranean Lagoons with Oyster Embryo Bioassay by F. Galgani; J. Senia; J. L. Guillou; T. Laugier; D. Munaron; B. Andral; B. Guillaume; E. Coulet; P. Boissery; L. Brun; M. C. Bertrandy (pp. 540-551).
In order to better understand environmental disturbances in the French coastal Mediterranean lagoons, we used an ecotoxicological approach based on the measurement of the toxicity of the sediments using oyster embryo bioassay that provides a basis for assessing the effects on the fauna of contaminants adsorbed on the sedimentary particles. The study covers all of the main lagoons of the French Mediterranean coasts of Languedoc Roussillon, Camargue, and Provence (Berre and Bolmon lagoons), where 188 stations were sampled. The toxicity tests provide evidence of variable levels of toxicity in sediments. Contaminated lagoons such as La peyrade, Le canet, and Ingrill and locally affected lagoons such as Bages–Sigean, Vaccares, Bolmon, and Berre have sampling stations with 100% of larval abnormalities during 24-h development. In all of the lagoons, the toxicity was mainly located close to local harbors and rivers. Salses Leucate (Languedoc roussillon) lagoon was found very clean, with no important toxicity. The results are discussed in terms of environmental disturbances of the coastal lagoons and with regard to the long-term monitoring of the impact of contaminants on the coastal environment.
Perfluoroalkyl Acids in Marine Organisms from Lake Shihwa, Korea by Hoon Yoo; Nobuyoshi Yamashita; Sachi Taniyasu; Kyu Tae Lee; Paul D. Jones; John L. Newsted; Jong Seong Khim; John P. Giesy (pp. 552-560).
To our knowledge, this is the first report of concentrations of perfluorooctanesulfonate (PFOS) and other perfluoroalkyl acids (PFAs) in marine organisms from the industrialized region of Korea. Concentrations of eight PFAs were determined in three species of fish (mullet, shad, and rockfish) and three species of marine invertebrates (blue crab, oyster, and mussel) from Lake Shihwa, Korea. This is an area in which relatively great concentrations of PFAs in water and in adjacent industrial effluents have been reported. PFOS was the dominant PFA in marine organisms and most PFOS concentrations were greater than the sum of all other PFAs. The mean concentrations of PFOS were 8.1 × 10 and 3.6 × 10 ng/g, wet weight in liver and blood of fish, respectively. Perfluorocarboxylic acids (PFCAs) were also found in fish, but their concentrations were 10-fold less than those for PFOS. Of the PFCAs measured in fish, concentrations of the longer-chain perfluoroundecanoic acid (PFUnA) were the greatest. Concentrations of PFOS in soft tissues of blue crabs decreased as a function of distance from the shore where inputs from the industrialized areas are discharged into Lake Shihwa. PFOS was the only PFA detectable in mussels and oysters with a mean of 0.5 ± 0.2 and 1.1 ± 0.3 ng/g, wet weight, respectively. Concentrations of PFUnA were positively correlated with perfluorodecanoic acid (PFDA) in both the liver and blood of fish, which suggests a common source of these two PFCAs in this area. Hazard quotients developed for fish species were all less than 1.0 for fish collected in Lake Shihwa.
Phase I Enzyme Induction in Girardinichthys viviparus, an Endangered Goodeid Fish, Exposed to Water from Native Localities Enriched with Polychlorinated Biphenyls by Armando Vega-López; F. Alejandro Jiménez-Orozco; Luís A. Jiménez-Zamudio; Ethel García-Latorre; M. Lilia Domínguez-López (pp. 561-570).
The present study examines the induction of mixed-function oxidase (MFO) enzymes, including CYP content CYP1A (EROD) activity and alcohol dehydrogenase activity (ADH), in an endemic Mexican fish species, the black-fin goodeid Girardinichthys viviparus, exposed to the water of two localities, Lake Texcoco (LTX) and Lake Zumpango, and to the same matrices enriched in polychlorinated biphenyls (PCBs) to simulate the potential toxic effects of sublethal increases in these xenobiotics. Fishes of both sexes born in the laboratory were exposed for 1, 2, 4, 8, and 16 days. Water from the two types of localities of the black-fin goodeid contains MFO inducers. Of the two, the most contaminated is LTX water, which also contains PCBs. EROD activity was higher in all treatments with female compared with male fish. This suggests greater metabolic compromise in female fish as a response to damage caused by these xenobiotics. In this species, CYP induction displayed two patterns that were not always concurrent with higher CYP1A activity. In the enriched matrix system, biotransformation processes were notably altered. Increased ADH may indicate that this enzyme is involved in the biotransformation of PCBs and their metabolites, particularly in male fish, and provides at least a part of reductive power required by the MFO enzymes; however, specific studies are needed to clarify this point.
Influence of the Route of Exposure on the Accumulation and Subcellular Distribution of Nickel and Thallium in Juvenile Fathead Minnows (Pimephales promelas) by Dominique Lapointe; Patrice Couture (pp. 571-580).
In this study, we examine the relative contribution of water and live prey (Tubifex tubifex) as sources of nickel (Ni) and thallium (Tl) in juvenile fathead minnows (Pimephales promelas). Overall, both water and prey were important sources of metals for our fish, although only approximately 35% of the metal estimated available for trophic transfer in the prey was assimilated. We also investigated the influence of exposure route on the subcellular distribution of these two metals. Once assimilated, most of the Ni was found in the granules, debris, and heat-stable protein (HSP), regardless of the route of exposure. Thallium was also mostly located in granules, debris, and HSP, and fish exposed from both water and prey had a higher proportion of Tl bound to the HSP compartment compared to control fish. Our results, obtained using environmentally relevant concentrations, suggest the presence of regulation mechanisms for both metals. Nevertheless, we measured increased metal concentrations in potentially metal-sensitive subcellular fractions when fish were exposed from water and diet simultaneously compared to a single route of exposure, suggesting that exposure to Ni and Tl from both routes could represent a risk of toxicity.
Comparison of Arsenic and Antimony Contents in Tissues and Organs of Brown Trout Caught from the River Presa Polluted by Ancient Mining Practices and from the River Bravona in Corsica (France): A Survey Study by J. Foata; Y. Quilichini; J. Torres; E. Pereira; M. M. Spella; J. Mattei; B. Marchand (pp. 581-589).
The present study evaluates the concentrations of arsenic (As) and antimony (Sb) in the intestine, liver, muscle, gonads, gills, and kidney of Salmo trutta subsp. from the Presa River in Corsica (France; n = 10), which crosses an abandoned arsenic mine, and from the Bravona River (reference site; n = 10). Both metalloids were analyzed by means of ICP-MS. The relationships between fish size (length and weight) and metalloid concentrations in their tissues were investigated by linear regression analysis. In all fish samples concentrations of As and Sb (expressed as micrograms per gram fresh weight) were highest in the kidney. Lowest Sb concentrations were found in the muscle, whereas lowest As concentrations were found in the gonads of S. trutta. Two organotropisms were revealed: one for As—kidney (21.4656) > intestine (3.9535) > gills (3.0404) > liver (1.1743) > muscle (0.9976) > gonads (0.8081); and the other for Sb—kidney (0.70067) > gills (0.6181) > intestine (0.2576) > gonads (0.1673) > liver (0.9625) > muscle (0.0753). Results of linear regression analysis in most cases showed a significant negative correlation between metalloid concentration and fish size. Highly significant (p < 0.05) negative correlations were found between fish length and As concentration in the gonads, as well as between fish length and Sb concentrations in the gills. Arsenic concentrations in female fish were significantly higher than those in males in the kidney, gonads, gills, and liver. The same results were found for Sb, except in the liver, where the tendency was reversed.
Behavioral Response and Kinetics of Terrestrial Atrazine Exposure in American Toads (Bufo americanus) by S. I. Storrs Méndez; D. E. Tillitt; T. A. G. Rittenhouse; R. D. Semlitsch (pp. 590-597).
Amphibians in terrestrial environments obtain water through a highly vascularized pelvic patch of skin. Chemicals can also be exchanged across this patch. Atrazine (ATZ), a widespread herbicide, continues to be a concern among amphibian ecologists based on potential exposure and toxicity. Few studies have examined its impact on the terrestrial juvenile or adult stages of toads. In the current study, we asked the following questions: (1) Will juvenile American toads (Bufo americanus) avoid soils contaminated with ATZ? (2) Can they absorb ATZ across the pelvic patch? (3) If so, how is it distributed among the organs and eventually eliminated? We conducted a behavioral choice test between control soil and soil dosed with ecologically relevant concentrations of ATZ. In addition, we examined the uptake, distribution, and elimination of water dosed with 14C-labeled ATZ. Our data demonstrate that toads do not avoid ATZ-laden soils. ATZ crossed the pelvic patch rapidly and reached an apparent equilibrium within 5 h. The majority of the radiolabeled ATZ ended up in the intestines, whereas the greatest concentrations were observed in the gall bladder. Thus, exposure of adult life stages of amphibians through direct uptake of ATZ from soils and runoff water should be considered in risk evaluations.
Perchlorate Exposure Induces Hypothyroidism and Affects Thyroid-Responsive Genes in Liver But Not Brain of Quail Chicks by Yu Chen; F. M. Anne McNabb; Jill C. Sible (pp. 598-607).
Ground-dwelling birds in perchlorate-contaminated areas are exposed to perchlorate ion, a known thyroid disruptor, and might be vulnerable to the developmental effects of perchlorate-induced hypothyroidism. We hypothesized that perchlorate-induced hypothyroidism would alter the expression of thyroid-responsive genes involved in thyroid hormone (TH) regulation and in the development of target organ function. Japanese quail chicks were exposed to 2000 mg/L ammonium perchlorate in drinking water for 7.5 weeks beginning on day 5 posthatch. Hypothyroidism was evident after 2 weeks of exposure as lower plasma THs and lower TH content in exposed chicks than in controls. The degree of hypothyroidism was increased at 7.5 weeks, as indicated by significant thyroid gland hypertrophy and sustained changes in thyroid function. After 2 weeks of exposure, hypothyroidism increased type 2 5′-deiodinase (D2) mRNA level and decreased Spot 14 (SP14) mRNA level in the liver, whereas D2 mRNA and RC3 mRNA levels in brain were not affected. After 7.5 weeks of exposure, mRNA levels in the exposed group did not differ from those in controls in either the liver or brain, suggesting the responsiveness of these genes to THs decreased during development. These results suggest that the brain, but not the liver, was protected from the effects of hypothyroidism, probably by changes in D2 activity at the protein level and/or regulation of TH entry and exit from the brain. We concluded that perchlorate exposure caused hypothyroidism in young Japanese quail and affected the expression of thyroid-responsive genes during early posthatch development.
Development and Use of Real-Time Reverse Transcription-Polymerase Chain Reaction Assay to Quantify Cytochrome P4501A1 Expression in American Mink by Nirmal K. Roy; Steve Bursian; David T. Mayack; Isaac Wirgin (pp. 608-615).
The distribution of natural populations of American mink is restricted to locales that are in proximity to aquatic ecosystems. Because of the lipophilicity and persistence of polychlorinated biphenyls (PCBs) and reliance of mink on aquatic-based diets, mink at contaminated locales often bioacccumulate high levels of PCBs. In addition, in controlled laboratory studies, mink are highly sensitive at reproductive and developmental end points to the toxic effects of environmental PCB mixtures. It is believed that most, if not all, toxic effects of PCBs occur through activation of the aryl hydrocarbon receptor (AHR) pathway. Transcription of cytochrome P4501A1 (CYP1A1) by PCBs is also mediated through activation of AHR. Thus, levels of CYP1A1 mRNA provide a quantitative assay of exposure to and early biologic effect of PCBs on mink and may be predictive of toxicity at higher levels of biologic organization. We developed polymerase chain reaction (PCR) primers to amplify CYP1A1 as well as identified a housekeeping gene from mink cDNA. We used real-time reverse transcription-PCR to quantify and compare levels of hepatic CYP1A mRNA among groups of ranched mink kits and juveniles, which were fed diets or exposed in utero to fish that were low in PCBs (Atlantic herring) or to diets that were contaminated with three different levels of PCBs (carp) from Saginaw Bay, Lake Michigan. We found significant differences in CYP1A1 mRNA expression between mink fed the control diet and those fed a PCB-contaminated carp diet at all three treatment levels and exposure times. CYP1A1 mRNA was significantly induced 5.3- to 6.6-fold and 3.7- to 4.7-fold at 6 and 27 weeks, respectively. In previous studies, dietary exposures to PCB-contaminated carp were shown to cause mild to moderate lesions in the mandible and maxilla of these animals. This study demonstrates that hepatic CYP1A1 mRNA may be a sensitive biomarker of exposure of mink to environmentally relevant levels of PCBs and may be predictive of their effects in natural populations.
Persistent Organochlorine Compounds in Human Milk Collected in Croatia Over Two Decades by B. Krauthacker; A. Votava-Raić; S. Herceg Romanić; D. Tješić-Drinković; Do. Tješić-Drinković; E. Reiner (pp. 616-622).
The distribution and time trend of organochlorine pesticide (OCP), polychlorinated biphenyl (PCB), and polychlorinated dibenzo-p-dioxin/polychlorinated dibenzofuran (PCDD/PCDF) concentrations in human milk samples from Croatia collected in 1981–2003 are presented. Between 1981/1982 and 1987/1989, the concentrations of HCB, β-HCH, DDE, and total PCBs decreased about 50%, while for the last decade, the concentrations have been decreasing very slowly. In 2002/2003 the range of PCB congeners and OCPs was from below the limit of determination to 332 ng g−1 milk fat. PCDD/PCDF concentrations in human milk samples collected in 1981–2000 ranged between 5.2 and 26.7 pg I-TEQ g−1 milk fat and showed a decreasing trend.
Urinary Paranitrophenol, a Metabolite of Methyl Parathion, in Thai Farmer and Child Populations by Parinya Panuwet; Tippawan Prapamontol; Somporn Chantara; Prasak Thavornyuthikarn; Roberto Bravo; Paula Restrepo; Robert D. Walker; Bryan L. Williams; Larry L. Needham; Dana B. Barr (pp. 623-629).
Human exposure to methyl parathion can be assessed by measuring the concentration of its metabolite paranitrophenol (PNP) in urine. Our biologic monitoring study in Chiang Mai, Thailand, measured PNP and dialkylphosphate metabolites (i.e., dimethylphosphate [DMP] and dimethylthiophosphate [DMTP]) of methyl parathion in urine samples collected from 136 farmers (age 20 to 65 years) and 306 school children (age 10 to 15 years) in 2006. Participants came from two topographically different areas: one was colder and mountainous, whereas the other was alluvial with climate fluctuations depending on the monsoon season. Both children and farmers were recruited from each area. Despite methyl parathion’s prohibited use in agriculture in 2004, we detected PNP in >90% of all samples analyzed. We applied a nonparametric correlation test (PNP vs. DMP and DMTP) to determine whether the PNP found in most of the samples tested resulted from exposures to methyl parathion. DMP (Spearman’s rho = 0.601 [p = 0.001] for farmers and Spearman’s rho = 0.263 [p <0.001] for children) and DMTP (Spearman’s rho = 0.296 [p = 0.003] for farmers and Spearman’s rho = 0.304 [p<0.001] for children) were positively correlated with PNP, suggesting a common source for the three analytes, presumably methyl parathion or related environmental degradates. Although we found a modest correlation between the metabolites, our findings suggest that despite the prohibition, at least a portion (approximately 25% to 60%) of the PNP detected among farmers and children in Thailand may be attributed to exposure from continued methyl parathion use.