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Archives of Environmental Contamination and Toxicology (v.62, #1)

Bioavailability of Copper and Zinc in Mining Soils by Ben A. Smith; Bruce Greenberg; Gladys L. Stephenson (pp. 1-12).

The soil-contact exposure pathway can be the main driver of ecological risk assessments. There is currently no standard method to measure bioavailability of metals in soil to ecological receptors, yet the influence of metal bioavailability on toxicity has been known for decades and is a major factor influencing risk to ecological receptors. Bioavailability is to a large degree governed by varying soil characteristics within and among sites, yet ecological screening benchmarks are often derived on a total-concentration basis. We compared a calcium chloride (CaCl₂) extraction, cyclodextrin extraction, simulated earthworm gut (SEG) test, earthworm kinetic bioaccumulation test, and metal residues in plant tissues with a battery of invertebrate and toxicity tests using mining soils consisting of high organic-matter content cocontaminated with copper (Cu) and zinc (Zn). Earthworm (Eisenia andrei) tissue concentrations of Cu and Zn were regulated and were not predictive of invertebrate toxicity. All chemical measures of bioavailability correlated with several biological responses; however, CaCl₂-extractable Cu and SEG-extractable Cu and Zn best predicted effects to E. andrei. Total Cu concentrations in soil best correlated with effects to plants. Overall, a chemical measure was the best predictor of toxicity to each organism compared with biological measures, although the exact measure was dependent on organism and end point. Chemical-extraction techniques provide relatively quick, inexpensive indicators of essential metal bioavailability compared with biological measures; however, no single measure was indicative of all effects to all organisms.

A Multidisciplinary Approach for Assessing the Toxicity of Marine Sediments: Analysis of Metal Content and Elutriate Bioassays Using Metal Bioavailability and Genotoxicity Biomarkers by Stefania Frassinetti; Emanuela Pitzalis; Marco Carlo Mascherpa; Leonardo Caltavuturo; Elisabetta Morelli (pp. 13-21).

The goal of this article is to verify the applicability of two different biological assays for studying a coastal area that is subject to anthropogenic inputs. Phytochelatins in the marine diatom Thalassiosira weissflogii were used as a biomarker of metal bioavailability. The frequency of genetic damage in the sensitive D7 strain of the yeast Saccharomyces cerevisiae was used to estimate the mutagenic potential. Biological assays were carried out using sediment elutriates. Sediments were collected at three selected sites located in the Gulf of Follonica (Tuscany, Italy), during a 2-year sampling period: Cala Violina (reference site) and the mouths of the rivers Pecora and Cornia, named sites V, P and C, respectively. The chemical characterization of each site was determined in terms of metal concentrations (As, Cd, Cr, Cu, Ni, Pb), measured in 11 sediment samples for each site. The results showed that metal concentrations in sediments from sites C and P were 2–10 times higher than the reference values (site V, year 2004). In addition, we found generally higher metal concentrations in the 2007 sediments than in the 2008 ones, including those of site V, due to the occurrence of an unexpected pollution event. This enabled us to obtain a pollution gradient to validate the proposed bioassays. In fact, the bioassays showed a potential biological hazard in the 2007 elutriates. Significant mutagenic effects were found in samples exhibiting higher concentrations of Cd and Cr. The induction of phytochelatins in T. weissflogii correlated positively with the Cd concentration in the elutriates.

Bioaccumulation and Effects of Metals Bound to Sediments Collected from Gulf of Cádiz (SW Spain) Using the Polychaete Arenicola marina by Judit Kalman; Inmaculada Riba; Angel DelValls; Julian Blasco (pp. 22-28).

A short-term whole-sediment test using the polychaete Arenicola marina was conducted under laboratory conditions to assess the bioavailability of metals bound to sediments collected from 12 sites of the Gulf of Cádiz. To achieve this objective, the rate of increase of metal bioaccumulation and the induction of a typical biomarker, metallothioneinlike proteins (MTLPs) were determined. Results of the multivariate analysis showed associated metal-rich sediments, increased rate of Cu and Zn accumulations, but lower toxicity with an increased MTLP induction, whereas sedimentary Ni and Co concentrations were related to higher toxicity to lugworms, although it might be caused by other contaminants present in these sediments. The linear kinetic approach was shown to be valid in certain circumstances, but more validation studies of this parameter are required before it can be recommended for use in evaluating metal bioavailability in sediments.

Seasonal Changes of Macroinvertebrate Communities in a Stormwater Wetland Collecting Pesticide Runoff From a Vineyard Catchment (Alsace, France) by Sylvain Martin; Aurélie Bertaux; Florence Le Ber; Elodie Maillard; Gwenaël Imfeld (pp. 29-41).

Agricultural land use may influence macroinvertebrate communities by way of pesticide contamination associated with agricultural runoff. However, information about the relation between runoff-related pesticides and communities of benthic macroinvertebrates in stormwater wetland that receive agricultural runoff does not currently exist. Here we show changes in macroinvertebrates communities of a stormwater wetland that collects pesticide-contaminated runoff from a vineyard catchment. Sixteen runoff-associated pesticides, including the insecticide flufenoxuron, were continuously quantified at the inlet of the stormwater wetland from April to September (period of pesticide application). In parallel, benthic macroinvertebrate communities, pesticide concentrations, and physicochemical parameters in the wetland were assessed twice a month. Twenty-eight contaminated runoffs ranging from 1.1 to 114 m³ entered the wetland during the study period. Flufenoxuron concentrations in runoff-suspended solids ranged from 1.5 to 18.5 μg kg⁻¹ and reached 6 μg kg⁻¹ in the wetland sediments. However, flufenoxuron could not be detected in water. The density, diversity, and abundance of macroinvertebrates largely varied over time. Redundancy and formal concept analyses showed that concentrations of flufenoxuron, vegetation cover, and flow conditions significantly determine the community structures of stormwater wetland macroinvertebrates. This study shows that flow conditions, vegetation cover, and runoff-related pesticides jointly affect communities of benthic macroinvertebrates in stormwater wetlands.

Partitioning Characteristics of Perfluorooctane Sulfonate Between Water and Foods by Feng Xiao; Matt F. Simcik; John S. Gulliver (pp. 42-48).

As a persistent, bioaccumulative, and toxic organic pollutant, perfluorooctane sulfonate (PFOS) has been found ubiquitously in the environment, including in tap water. For the first time, we studied PFOS sorption from water to foods (nine commonly consumed vegetables, three meats, and cereals) at two temperatures to estimate the daily intake of PFOS attributable to cooking and food preparation. The values of the food water-distribution coefficient (K _F/W, l/kg) of PFOS ranged from 7 to 19 l/kg for most vegetables and from 19 to 38 l/kg for meats. Celery exhibited the highest affinity toward PFOS (K _F/W = 39.8 ± 3.4 l/kg), whereas onions showed the lowest affinity toward PFOS (K _F/W = 1.1 ± 0.4 l/kg). Adding table salt (sodium chloride) greatly increased PFOS sorption in most foods, except for celery and meats. The results indicate that human exposure to PFOS could result from the sorption of PFOS from water to food during food preparation, especially when using table salt. The average daily intake of PFOS through this route was estimated. Furthermore, raw and unprocessed foods (vegetables, meats, and cereals) bought from farmers’ markets and grocery stores were basically free of PFOS and other long-chain perfluoroalkyl acids.

Toxicity of Polyfluorinated and Perfluorinated Compounds to Lettuce (Lactuca sativa) and Green Algae (Pseudokirchneriella subcapitata) by Guanghui Ding; Marja Wouterse; Rob Baerselman; Willie J. G. M. Peijnenburg (pp. 49-55).

Recently, polyfluorinated and perfluorinated compounds (PFCs) have been detected in most surface waters around the world. Because some PFCs are persistent and tend to accumulate in surface waters, their potential adverse effects to aquatic organisms have received increasing attention. Nevertheless, currently available toxicity information is limited. The aim of this study was to evaluate the toxicity effects of seven PFCs on root elongation of lettuce (Lactuca sativa) and photosynthesis of green algae (Pseudokirchneriella subcapitata). It was found that the toxicity profiles of both species tested were similar and had good relations with the fluorinated carbon-chain length of the PFCs investigated. One of the compounds tested, perfluorobutanoic acid, was found to be more toxic than expected in the algae test, which may be related with acidification of the test solution. It was concluded that because short-chained PFCs are becoming the predominant PFC pollutants in surface waters, their long-term toxicity and mixture toxicity with other PFCs should be studied in greater detail.

The Influence of Lead on Different Proteins in Gill Cells From the Freshwater Bivalve, Corbicula fluminea, From Defense to Repair Biomarkers by Caroline T. Rocha; Marta M. Souza (pp. 56-67).

The objective of this study was to evaluate the influence of lead (Pb) on regulatory proteins linked to mechanisms of animal adaptation to polluted environments (using in vivo and in vitro tests) and to validate the in vitro assay as a tool for environmental assessment. Specimens of the bivalve Corbicula fluminea were exposed to nominal concentrations of Pb 5 mg l⁻¹ for 96 h. Isolated gill cells were exposed to three concentrations (1, 10, and 100 μM) for 5 h. Metal toxicity was evaluated by cell viability (trypan blue exclusion). We also analyzed Na⁺/K⁺ adenosine triphosphatase (ATPase) and carbonic anhydrase activity. Additionally, the multixenobiotic-resistance (MXR) phenotype was evaluated by the accumulation of rhodamine B (RB). Immunolabeling was used to quantify the expression of P-glycoproteins (C219) and proteins involved in ion transport, water movement, and cellular repair using antibodies against Na⁺/K⁺ ATPase, aquaporin 1, and heat-shock protein 70 (Hsp70). Pb was shown to be toxic in both in vivo and in vitro tests, in which cellular viability significantly decreased by approximately 25%. Cellular viability in the in vivo assays was determined by gill cell isolation after the entire animal was exposed to Pb. We observed that Na⁺/K⁺ ATPase activity was inhibited by 70%. Also, the expression of the MXR phenotype significantly increased in our in vivo tests. A statistically significant difference was observed in the expression of all proteins in the in vitro assays, whereas only Hsp70 increased in vivo. Employing these analyses, we could validate the sensitivity of the in vitro tests and can propose our in vitro model as a possible tool for environmental assessment.

Butyltin Compounds and Imposex Levels in Ecuador by Ítalo Braga Castro; Maria Fernanda Arroyo; Patrícia Gomes Costa; Gilberto Fillmann (pp. 68-77).

The first appraisal of butyltins (BT) contamination linked with imposex incidence in the Pacific coast of South America was performed in the current study. Imposex occurrence was analyzed in three muricid species (Thais biserialis, T. brevidentata, and T. kiosquiformis) distributed along 14 sites from the coastal areas of Ecuador. All studied muricids species showed imposex, which was observed in 11 out of 14 sites. The highest imposex levels were observed in T. kiosquiformis collected inside the Gulf of Guayaquil [relative penis length index (RPLI) 9.0–40.7], whereas RPLI values for T. biserialis and T. brevidentata ranged from 4.0 to 26.1 and 0.0 to 1.9, respectively. Additionally, BT compounds [tributyltin (TBT), dibutylin (DBT), and monobutylin (MBT)] were determined in surface sediments collected in 6 of the sites (main harbor areas), and values ranged between 12.7 and 99.5 ng Sn g⁻¹ (dry weight) for TBT, 1.8 and 54.4 ng Sn g⁻¹ for DBT, and 44 and 340 ng Sn g⁻¹ for MBT. Although BT degradation indexes suggested an aged input of TBT, the high imposex levels detected in the current study suggest that international restrictions on TBT based antifouling paints were still not effective in Ecuador. Considering that the southern coast, especially nearby harbors inside the Gulf of Guayaquil, have shown to be contaminated by BTs, a combination of T. kiosquiformis and T. biserialis (the most sensitive species) can be used for future biomonitoring of Ecuador coastal areas.

Sodium Fluxes in Tamoatá, Hoplosternum litoralle, Exposed to Formation Water from Urucu Reserve (Amazon, Brazil) by Bernardo Baldisserotto; Luciano O. Garcia; Ana Paula Benaduce; Rafael M. Duarte; Thiago L. Nascimento; Levy C. Gomes; Adriana R. Chippari Gomes; Adalberto L. Val (pp. 78-84).

Formation water (produce water or oil field brine) from oil and gas production usually has high concentrations of soluble salts and metals. The objective of this study was to examine the effect of formation water from Urucu Reserve, Amazon, on whole-body uptake and internal distribution of newly accumulated Na⁺ in juvenile tamoatá, Hoplosternum litoralle. Groups of fish were submitted to nine treatments for 3 h in 400-ml chambers: control (well water), 5% formation water, and well water with respective concentrations of 5% formation water of Ca²⁺, Fe, Mn, Ba²⁺, Fe + Ca²⁺, Mn + Ca²⁺, and Ba + Ca²⁺ added. Specimens of tamoatá exposed to 5% formation water presented a very high Na⁺ influx, probably due to the high Na⁺ levels in this water. Waterborne Fe and Mn stimulated Na⁺ influx, but Fe increased Na⁺ efflux, causing Na⁺ loss. Waterborne Mn, on the other hand, decreased Na⁺ efflux, reducing Na⁺ loss by this species. Waterborne Ca²⁺ also affected Na⁺ influx but had no significant effect on net Na⁺ fluxes. These results demonstrated that spilling of formation water in ion-poor Amazon rivers would dramatically disrupt osmoregulatory balance of tamoatá and probably other Amazon fish species, impairing their survival and reduce biodiversity.

Occurrence of Halogenated Contaminants in Fish from Selected River Localities and Ponds in the Czech Republic by Petra Hrádková; Jana Pulkrabová; Kamila Kalachová; Veronika Hloušková; Monika Tomaniová; Jan Poustka; Jana Hajšlová (pp. 85-96).

The occurrence of organohalogenated compounds including major persistent chlorinated pollutants, such as polychlorinated biphenyls (PCBs) and DDT and its metabolites, brominated flame retardants (BFRs), represented by polybrominated diphenylethers (PBDEs) and hexabromocyclododecane (HBCD), together with currently widely discussed perfluorinated compounds (PFCs), mainly perfluorooctane sulfonic acid was monitored in several fish species collected from Czech rivers. Eleven sampling locations in highly industrialized areas were chosen. In addition, wild species of 14 farmed fish (grown in dedicated ponds) were also analysed. With respect to the contamination in different areas, chlorinated chemicals were dominant. PCBs and DDTs ranged from 4.8 to 211 and 2 to 791 μg/kg wet weight, respectively. Concentrations of BFRs and PFCs were significantly lower and ranged from 0.6 to 10.2 and 0.9 to 62 μg/kg wet weight, respectively. The highest levels of target analyte groups were found in fish muscle tissue in localities situated on the lower part of the Elbe River: Levels of DDT, HCB, PBDEs, and perfluorooctane sulfonic acid (PFOS) were as high as 791, 77.6, 14.4 and 193 μg/kg wet weight, respectively, in Usti nad Labem and in the sample originated from the confluence of Elbe with Bilina River; a sum of PCBs at a level of 211 μg/kg was detected.

Tissue Biochemical Alterations of Cyprinus carpio Exposed to Commercial Herbicide Containing Clomazone Under Rice-Field Conditions by Roberta Cattaneo; Bibiana Silveira Moraes; Vania Lucia Loro; Alexandra Pretto; Charlene Menezes; Gerson Meneghetti Sarzi Sartori; Bárbara Clasen; Luis Antonio de Avila; Enio Marchesan; Renato Zanella (pp. 97-106).

Field and laboratory experiments were performed to evaluate toxicological responses of Cyprinus carpio exposed to the commercial herbicide clomazone (500 mg l⁻¹). Fish were exposed to 0.5 mg l⁻¹ of the formulated herbicide for 7, 30, and 90 days. Fish were exposed to clomazone in field conditions (7, 30, or 90 days trapped in submersed cages together with rice crops) and in laboratory conditions where the fish were placed in 45-l tanks with tap water only for 7 days. Fish exposed for 7, 30, or 90 days showed no alterations in acetylcholinesterase (AChE) activity under field conditions. Under laboratory conditions, decreased muscle AChE activity was observed only after 7 days of exposure. During the same evaluation period (7 days), oxidative stress parameters changed under both field and laboratory conditions; however, metabolic parameters were altered only under field conditions. Disorders in oxidative stress parameters and metabolism were evident in different tissues up to day 90 after treatment. These overall results show that AChE activity changed only under laboratory conditions. Oxidative stress, along with metabolic parameters, may be good indicators of herbicide contamination in C. carpio under rice-field conditions.

Exposure to a Commercial Glyphosate Formulation (Roundup^®) Alters Normal Gill and Liver Histology and Affects Male Sexual Activity of Jenynsia multidentata (Anablepidae, Cyprinodontiformes) by Andrea Cecilia Hued; Sabrina Oberhofer; María de los Ángeles Bistoni (pp. 107-117).

Roundup is the most popular commercial glyphosate formulation applied in the cultivation of genetically modified glyphosate-resistant crops. The aim of this study was to evaluate the histological lesions of the neotropical native fish, Jenynsia multidentata, in response to acute and subchronic exposure to Roundup and to determine if subchronic exposure to the herbicide causes changes in male sexual activity of individuals exposed to a sublethal concentration (0.5 mg/l) for 7 and 28 days. The estimated 96-h LC₅₀ was 19.02 mg/l for both male and female fish. Gill and liver histological lesions were evaluated through histopathological indices allowing quantification of the histological damages in fish exposed to different concentrations of the herbicide. Roundup induced different histological alterations in a concentration-dependent manner. In subchronic-exposure tests, Roundup also altered normal histology of the studied organs and caused a significant decrease in the number of copulations and mating success in male fish exposed to the herbicide. It is expected that in natural environments contaminated with Roundup, both general health condition and reproductive success of J. multidenatata could be seriously affected.

Cadmium Accumulation and Antioxidant Responses in Sparus aurata Exposed to Waterborne Cadmium by T. Cirillo; R. Amodio Cocchieri; E. Fasano; A. Lucisano; S. Tafuri; M. C. Ferrante; E. Carpenè; G. Andreani; G. Isani (pp. 118-126).

Cadmium (Cd), a nonessential trace element, is rapidly accumulated by most living organisms and subsequently exerts its toxicity at different molecular levels. This study exposed gilthead sea bream (Sparus aurata) to waterborne 0.1 mg/l Cd for 11 days and investigated the Cd accumulation pattern, lipid oxidation, and response of antioxidant defences. At the end of the experiment, mean Cd concentrations in gills and liver, the organs most prone to metal accumulation, were 209.4 and 371.7 ng/g ww, respectively. Muscle did not show any Cd retention during the 11 days of exposure. In liver, the cytosolic fraction of the metal was chelated into the nontoxic form by metallothionein (MT), a specific Cd-inducible protein. Zn and Cu concentrations were not influenced by Cd exposure. Glutathione (GSH) concentrations and the antioxidant enzyme activities of GSH reductase and GSH peroxidase showed an overall decreasing trend. In addition, lipid and aqueous hydroperoxide levels did not show any significant variation. Oxidative stress indirectly generated by Cd seems to be compensated for by the different biochemical systems tailored to decrease cellular damage. In particular, the negative effects of Cd accumulation in tissues were probably counteracted by the induction of MT.

Proteomic Analysis of Hepatic Tissue in Adult Female Zebrafish (Danio rerio) Exposed to Atrazine by Yuanxiang Jin; Xiangxiang Zhang; Dezhao Lu; Zhengwei Fu (pp. 127-134).

Atrazine (ATZ), the most common herbicide, is a frequently observed contaminant in freshwater ecosystems. In the present study, two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization tandem time-of-flight-mass spectrometry, combined with histopathological analysis, were used to detect the hepatic damage in adult female zebrafish (Danio rerio) exposed to ATZ. More than 600 hepatic protein spots were detected in each gel with silver staining, and most of the proteins ranged from 20 to 70 kD and pH 4–9. Through comparison and analysis, 7 proteins were found to be upregulated >2-fold, whereas 6 protein spots were downregulated >2-fold after 10 and 1000 μg/l ATZ exposures for 14 days, which had caused histological effects in zebrafish livers. We found that these changed proteins were associated with a variety of cellular biological processes, such as response to oxidative stress, oncogenesis, etc. The results demonstrated that ATZ comprehensively influenced a variety of cellular and biological processes in zebrafish. The information presented in this study will be helpful in fully understanding the mechanism of the potential effects induced by ATZ in fish.

Mercury in Tadpoles Collected from Remote Alpine Sites in the Southern Sierra Nevada Mountains, California, USA by David F. Bradford; Joanna L. Kramer; Shawn L. Gerstenberger; Nita G. Tallent-Halsell; Maliha S. Nash (pp. 135-140).

Amphibians in alpine wetlands of the Sierra Nevada mountains comprise key components of an aquatic–terrestrial food chain, and mercury contamination is a concern because concentrations in fish from this region exceed thresholds of risk to piscivorous wildlife. Total mercury concentrations were measured in whole tadpoles of the Sierra chorus frog, Pseudacris sierra, two times at 27 sites from high elevations (2786–3375 m) in the southern Sierra Nevada. Median mercury concentrations were 14 ng/g wet weight (154 ng/g dry weight), which were generally low in comparison to tadpoles of 15 other species/location combinations from studies that represented both highly contaminated and minimally contaminated sites. Mercury concentrations in P. sierra were below concentrations known to be harmful in premetamorphic tadpoles of another species and below threshold concentrations for risk to predaceous wildlife. Concentrations in tadpoles were also lower than those observed in predaceous fish in the study region presumably because tadpoles in the present study were much younger (1–2 months) than fish in the other study (3–10 years), and tadpoles represent a lower trophic level than these fish. Mercury concentrations were not related to distance from the adjacent San Joaquin Valley, a source of agricultural and industrial pollutants.

Hormesis Associated with a Low Dose of Methylmercury Injected into Mallard Eggs by Gary H. Heinz; David J. Hoffman; Jon D. Klimstra; Katherine R. Stebbins; Shannon L. Kondrad; Carol A. Erwin (pp. 141-144).

We injected mallard (Anas platyrhynchos) eggs with methylmercury chloride at doses of 0, 0.05, 0.1, 0.2, 0.4, 0.8, 1.6, 3.2, and 6.4 μg mercury/g egg contents on a wet-weight basis. A case of hormesis seemed to occur because hatching success of eggs injected with 0.05 μg/g mercury (the lowest dose) was significantly greater (93.3%) than that of controls (72.6%), whereas hatching success decreased at progressively greater doses of mercury. Our finding of hormesis when a low dose of methylmercury was injected into eggs agrees with a similar observation in a study in which a group of female mallards was fed a low dietary concentration of methylmercury and hatching of their eggs was significantly better than that of controls. If methylmercury has a hormetic effect at low concentrations in avian eggs, these low concentrations may be important in a regulatory sense in that they may represent a no-observed adverse effect level (NOAEL).

Copper Pellets Simulating Oral Exposure to Copper Ammunition: Absence of Toxicity in American Kestrels (Falco sparverius) by J. Christian Franson; Lesanna L. Lahner; Carol U. Meteyer; Barnett A. Rattner (pp. 145-153).

To evaluate the potential toxicity of copper (Cu) in raptors that may consume Cu bullets, shotgun pellets containing Cu, or Cu fragments as they feed on wildlife carcasses, we studied the effects of metallic Cu exposure in a surrogate, the American kestrel (Falco sparverius). Sixteen kestrels were orally administered 5 mg Cu/g body mass in the form of Cu pellets (1.18–2.00 mm in diameter) nine times during 38 days and 10 controls were sham gavaged on the same schedule. With one exception, all birds retained the pellets for at least 1 h, but most (69%) regurgitated pellets during a 12-h monitoring period. Hepatic Cu concentrations were greater in kestrels administered Cu than in controls, but there was no difference in Cu concentrations in the blood between treated and control birds. Concentration of the metal-binding protein metallothionein was greater in male birds that received Cu than in controls, whereas concentrations in female birds that received Cu were similar to control female birds. Hepatic Cu and metallothionein concentrations in kestrels were significantly correlated. Histopathologic alterations were noted in the pancreas of four treated kestrels and two controls, but these changes were not associated with hepatic or renal Cu concentrations, and no lesions were seen in other tissues. No clinical signs were observed, and there was no treatment effect on body mass; concentrations of Cu, hemoglobin, or methemoglobin in the blood; or Cu concentrations in kidney, plasma biochemistries, or hematocrit. Based on the parameters we measured, ingested Cu pellets pose little threat to American kestrels (and presumably phylogenetically related species), although the retention time of pellets in the stomach was of relatively short duration. Birds expected to regurgitate Cu fragments with a frequency similar to kestrels are not likely to be adversely affected by Cu ingestion, but the results of our study do not completely rule out the potential for toxicity in species that might retain Cu fragments for a longer time.

Liver Injury and Its Molecular Mechanisms in Mice Caused by Exposure to Cerium Chloride by Haiquan Zhao; Jie Cheng; Jingwei Cai; Zhe Cheng; Yaling Cui; Guodong Gao; Renping Hu; Xiaolan Gong; Ling Wang; Fashui Hong (pp. 154-164).

Cerium has been demonstrated to damage liver of mice, but very little is known about the molecular mechanisms underlying the mouse liver apoptosis. In order to understand the liver injury induced by intragastric administration of cerium chloride (CeCl₃) for 60 consecutive days, the hepatocyte ultrasrtucture, various oxidative stress parameters, and the stress-related gene expression levels were investigated for the mouse liver. The results demonstrated that CeCl₃ had an obvious accumulation in the mouse liver, leading to a classical laddering cleavage of DNA and hepatocyte apoptosis. CeCl₃ significantly promoted the accumulation of reactive oxygen species and inhibited the stress-related gene expression of superoxide dismutase, catalase, glutathione peroxidase, metallothionein, heat-shock protein 70, glutathione-S-transferase, P53, and transferring, and it effectively activated the cytochrome p450 1A. It implied that CeCl₃ resulted in apoptosis and alteration of expression levels of the genes related with metal detoxification/metabolism regulation and radical scavenging action in mice.

Bone-Prognostic Status After Cessation of Cadmium Exposure for One Month in Male Rats by Xiao Chen; Guoying Zhu; Taiyi Jin; Chunlin Shao; Shuzhu Gu; Mingguang Tan; Yanyan Zhang; Hanfang Xiao; Heping Hu; Yunzhen Yu (pp. 165-175).

This study investigated bone status after decreased cadmium (Cd) exposure in male rats. Sprague–Dawley male rats were randomly divided into three groups. One group was injected subcutaneously with sodium chloride as control. The others were given CdCl₂ by subcutaneous injection at doses of 0.5 mg Cd/kg body weight (bw) for 2 months (Cd+2m) and for 3 months (Cd+3m). For the Cd+2m group, the rats were shifted to cessation of Cd injection for 1 month after 2 months’ exposure. At month 3, micro-computed tomography (micro-CT) analyses were performed on the proximal tibia and lumbar spine, and urine was collected from all rats. Rats were then killed and blood collected for metabolic-marker measurement and Cd assay. Bone tissues were also collected for bone-mass assay, biomechanical test, and bone-histology analysis. Cd burdens of rats in the Cd+2m and Cd+3m groups were both significantly greater than those in the control group. Cd burdens of rats were lower in the Cd+2m group compared with the Cd+3m group. Bone damage occurred in the Cd+2m and Cd+3m groups compared with the control group (p < 0.05), but no significant improvement was found in the Cd+2m group compared with the Cd+3m group. Cd damage to bone could not be reversed over the short term. More attention should be paid to Cd’s toxic effects on bone after decreased exposure.

Polybrominated Diphenyl Ethers, Polychlorinated Biphenyls, and Organochlorine Pesticides in Adipose Tissues of Korean Women by Hyo-Bang Moon; Duk-Hee Lee; Yoon Soon Lee; Minkyu Choi; Hee-Gu Choi; Kurunthachalam Kannan (pp. 176-184).

Studies on residue levels and accumulation profiles of persistent organic pollutants (POPs) in human adipose tissues of Korean populations are scarce. In this study, concentrations and accumulation features of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) were measured in adipose tissues of Korean women age 40–68 years. The highest concentrations were found for PCBs and DDTs, which were 1–2 orders of magnitude greater than the concentrations of hexachlorocyclohexanes, chlordanes, and PBDEs. The concentrations of PCBs and OCPs were lower than those reported for other countries. However, PBDE concentrations were greater than those reported for other countries, suggesting that ongoing exposure to PBDEs is a concern in Korea. The profiles of PBDEs were characterized by the predominance of BDE 209, followed by nona- and octa-BDEs, which are consistent with the consumption patterns of products containing PBDEs in Korea. The concentrations of PCBs and some OCPs were significantly correlated with each other, whereas PBDEs showed low or moderate correlations with other POPs, suggesting differences in exposure routes and biotransformation potentials of the compounds studied. The concentrations of organochlorines and PBDEs were not correlated with subjects’ age and body mass index. The results of this study provide baseline information on POPs in adipose tissues of the general population in Korea.

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Archives of Environmental Contamination and Toxicology (v.62, #1)