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Archives of Environmental Contamination and Toxicology (v.45, #3)

Joint Toxicity of Similarly and Dissimilarly Acting Chemicals to Daphnia magna at Different Response Levels by Daniel Merino-García; K. Ole Kusk; Erik R. Christensen (pp. 289-296).

The toxicity of two amines, nonylamine and decylamine, which have a narcotic effect on organisms, and ethylparathion (enzymatic inhibitor) on Daphnia magna has been studied when acting singly and in joint toxicity tests. This was done on the basis of an isobologram method where curves of constant response, i.e., isoboles are plotted vs. the concentrations of the two toxicants. The concentrations that immobilized 50, 10, and 0% of the test population in 48 h (IC50-48h, IC10-48h, and IC0-48h) were calculated. It is shown that nonylamine–decylamine mixtures follow a near concentration addition model of joint toxicity, while ethylparathion–decylamine mixtures follow a less than additive or near independent action model. The study was performed using three toxicity indices: additive index, sum of toxic units, and similarity parameter λ. An analysis of the similarity parameter λ is done to evaluate whether it has a constant value for IC50-48h, IC10-48h, and IC0-48h. The results suggest that it is quite probable that a constant value of λ can be used to characterize all response levels, as the isoboles corresponding to the average value of the similarity parameter fit within the 95% confidence intervals of toxicant concentrations at all response levels. The average value of λ is about 0.80 for the nonylamine–decylamine test and 0.30 for the ethylparathion–decylamine test.

Precision of Dialysis (Peeper) Sampling of Cadmium in Marine Sediment Interstitial Water by J. R. Serbst; R. M. Burgess; A. Kuhn; P. A. Edwards; M. G. Cantwell; M. C. Pelletier; W. J. Berry (pp. 297-305).

Isolating and analyzing interstitial water (IW) during sediment toxicity tests enables researchers to relate concentrations of contaminants to responses of organisms, particularly when IW is a primary route of exposure to bioavailable contaminants by benthic dwelling organisms. We evaluate here the precision of sampling IW with the dialysis or ‘peeper’ method using sediments spiked with five different concentrations of cadmium. This method is one of several that are commonly used for collecting IW. Seven consecutive ten-day toxicity tests were conducted on these sediments and IW samples were collected at the end of each of these tests. Prior to each test initiation and insertion of IW samplers, sediments were allowed to equilibrate for seven days under flow-through conditions with filtered seawater. At the end of each ten-day testing period, peepers were retrieved, and IW cadmium measured. Data sets were organized by treatment and test number. Coefficients of variation (CV) for the six replicates for each sediment and testing period and for each sediment across testing periods (42 replicates) was used as a measure of sampling precision. CVs ranged from 25 to 206% when individual testing periods were considered, but ranged from 39 to 104% when concentrations for all testing periods were combined. However, after removal of outliers using Dixon’s Criteria, the CVs improved and ranged from 6 to 88%. These levels of variability are comparable to those reported by others. The variability shown is partially explained by artifacts associated with the dialysis procedure, primarily sample contamination. Further experiments were conducted that support our hypothesis that contamination of the peeper causes much of the variability observed. If method artifacts, especially contamination, are avoided the dialysis procedure can be a more effective means for sampling IW metal.

Contaminants of Concern in Dutch Marine Harbor Sediments by J. Stronkhorst; B. van Hattum (pp. 306-316).

The status of the contamination of Dutch marine harbor sediments was reevaluated after a period in which emissions from point sources had been greatly reduced. Data on sediment chemistry from 1999 and 2000 were assessed against screening levels (SLs) selected from available sediment quality guidelines and representing a low probability of adverse biological effects. This yielded a ranking of the environmental hazard of 22 contaminants.Most of the sediments were silty material; every year 15 to 25 million m³ of such material is dredged from Dutch harbors. Some 34% of the volume exceeded one or more SLs. The contaminants of concern were tributyltin (TBT), mineral oil (petroleum hydrocarbons), polychlorinated biphenyls (PCBs), and mercury. The PCB and mercury contamination is the legacy of historic inputs; the TBT and mineral oil contamination is related to present-day shipping activity. Concentrations of trace metals, rare earth elements, organochlorine pesticides, and polycyclic aromatic hydrocarbons (PAHs) were low and apparently of minor environmental concern. It is concluded that the risk assessment would be improved by laboratory testing of adverse biological effects.

Energization of Comamonas testosteroni ATCC 17454 for Indicating Toxic Effects of Chlorophenoxy Herbicides by N. Loffhagen; C. Härtig; W. Babel (pp. 317-323).

The toxicity of chlorophenoxy herbicides to a bacterium, strongly related to the well-known species Delftia (formerly Comamonas) acidovorans that are able to detoxify these xenobiotics, was investigated. The oxidation of n-hexanol via alcohol dehydrogenases, coupled with the generation of ATP by electron transport phosphorylation (ETP), was used as an indicator for energy-toxic effects on the growth of Comamonas testosteroni ATCC 17454.Uncoupling—reductions in ATP synthesis accompanied by increased respiration—was found to be induced by 1 mM of the classic uncoupler 2,4-dinitrophenol (2,4-DNP) at pH 7.0 and 8.0. At pH 5.4 and 6.0, the ATP synthesis and respiration were strongly inhibited by both 2,4-DNP and the chlorophenoxy herbicides tested. In contrast, 5 mM of 2,4-dichlorophenoxyacetic acid (2,4-D) and of 2-(2,4-dichlorophenoxy)-propanoic acid (2,4-DCPP) were required for detectable uncoupling effects—reduction of the P/O ratios by about 30%—at pH 7.0. These chemicals may have less uncoupling power because the concentration of their protonated (undissociated) forms (pKa values 2.7 and 3.0) is an order of magnitude lower than that of 2,4-DNP (pKa = 4.0) at this pH value.Strong uncoupling accompanied by increased respiration, like that induced by 1 mM 2,4-DNP, was also caused by 5 mM 4-(2,4-dichlorophenoxy)-butyric acid (2,4-DCPB), which correlates with its high pKa value of 4.6.The order of toxicity of the chlorophenoxy herbicides (2,4-D < 2,4-DCPP < 2,4-DCPB) to the ETP, which correlates well with the lipophilicity of their undissociated forms (log P 2.7 < 3.4 < 3.5, respectively), was confirmed by measuring their capacity to inhibit the growth of Comamonas testosteroni ATCC 17454.The results show that energization via alcohol dehydrogenases can be used as an indicator for investigating energy-toxic effects of organics on the ETP and growth of chlorophenoxy herbicide-detoxifying bacteria.

Effects of Cysteine on the Cytotoxicity of Arsenic Compounds by X. Zhou; K. Yoshida; K. Kuroda; Y. Endo; G. Endo (pp. 324-330).

Effects of cysteine on the cytotoxicity of arsenic compounds, such as arsenite, arsenate, methylarsonic acid (MMA), and dimethylarsinic acid (DMA), were investigated in cultured human HL-60 cells. Using adenosine triphosphate bioluminescence assay, the rank order of the mixtures of arsenicals with cysteine was: DMA > arsenite > arsenate > MMA. The IC₅₀ of DMA with equimolar cysteine was approximately 7.7 μM, nearly two orders of magnitude lower than that of DMA alone. Apoptotic cells were examined by the TUNEL method, and cysteine was found to enhance the induction of apoptosis by arsenicals. Using LC-ICP-MS, trivalent arsenic was detected in the mixtures of arsenate, DMA, and MMA with cysteine. These results suggested that the trivalent arsenic in the mixtures of arsenicals with cysteine might account for the enhanced cytotoxicity as well as apoptosis, and that cysteine is involved in induction of the adverse effects of arsenicals in humans.

Acute Toxicity of Methyl-Parathion in Wetland Mesocosms: Assessing the Influence of Aquatic Plants Using Laboratory Testing with Hyalella azteca by R. Schulz; M. T. Moore; E. R. Bennett; C. D. Milam; J. L. Bouldin; J. L. Farris; S. Smith Jr.; C. M. Cooper (pp. 331-336).

Methyl-parathion (MeP) was introduced into constructed wetlands for the purpose of assessing the importance of distance from the source of contamination and the role of emergent vegetation on the acute toxicity to Hyalella azteca (Crustacea: Amphipoda). A vegetated (90% cover: mainly Juncus effuses) and a nonvegetated wetland (each with a water body of 50 × 5.5 × 0.2 m) were each exposed to a simulated MeP storm runoff event. H. azteca was exposed for 48 h in the laboratory to water samples taken from the wetlands at a distance of 5, 10, 20, and 40 m from the pesticide inlet 3 h, 24 h, 96 h, and 10 days following application. Methyl-parathion was detected throughout the nonvegetated wetland, whereas the pesticide was only transported halfway through the vegetated wetland. A repeated-measure three-way analysis of variance (ANOVA) using time, location, and vegetation indicated significantly lower toxicity in the vegetated wetland. Furthermore, the mortality decreased significantly with both increasing distance from the inlet and time (48-h LC₅₀ ± 95% CI: 9.0 ± 0.3 μg/L). A significant three-way interaction of time × vegetation × location confirmed higher toxicity at the inlet area of the nonvegetated wetland immediately after contamination. Significant linear regressions of maximum mortality (independent of time) versus distance from the pesticide inlet indicated that 44 m of vegetated and 111 m of nonvegetated wetland would reduce H. azteca mortality to ≤5%. These results suggest that vegetation contributes to reduced MeP effects in constructed wetlands.

Induction of Oxidative Stress in the Red Macroalga Gracilaria tenuistipitata by Pollutant Metals by J. Collén; E. Pinto; M. Pedersén; P. Colepicolo (pp. 337-342).

Heavy metals are environmental pollutants that have the potential to induce severe stress-reactions in organisms on land as well as in the sea. We have studied effects of short term sublethal concentrations of copper (Cu²⁺) and cadmium (Cd²⁺) on the reactive oxygen metabolism of the marine red macroalga Gracilaria tenuistipitata. Additions of either 0.2 ppm Cu²⁺ or 1 ppm Cd²⁺ caused decreased growth (∼60%), increased oxidation of lipids and increased oxidative damage to proteins as shown by increased content of protein carbonyl groups. Together this strongly suggests an induction of oxidative stress. Cu²⁺ caused more oxidative damage than Cd²⁺. As a response to the increased oxidative stress, addition of Cu²⁺ induced the activities of catalase, ascorbate peroxidase, and superoxide dismutase. In contrast, Cd²⁺ only caused increased catalase activity. Ten-fold lower concentrations of the metals did not cause an increase in enzyme activity. Both heavy metals also increased the content of the antioxidants β-carotene and lutein. The results show that Cd²⁺ and, to a larger extent, Cu²⁺ induce oxidative stress in short-term experiments and the seaweed responds by increasing the activity of the reactive oxygen metabolism.

Assessing the Impact of Triazine Herbicides on Organophosphate Insecticide Toxicity to the Earthworm Eisenia fetida by M. J. Lydy; S. L. Linck (pp. 343-349).

A standard Organization for Economic Cooperation and Development (OECD) filter paper test was used to assess the acute toxicity of chlorpyrifos, atrazine, cyanazine, and simazine to the earthworm Eisenia fetida. Acute toxicity of chlorpyrifos was also determined in combination with the three-triazine herbicides. Surprisingly, atrazine and cyanazine caused mortality at concentrations lower than chlorpyrifos. Atrazine and cyanazine also increased the toxicity of chlorpyrifos 7.9- and 2.2-fold, respectively. However, simazine caused no toxicity to the worms and did not affect chlorpyrifos toxicity in binary mixture experiments. Possible mechanisms for the greater-than-additive toxicity for the binary combinations of atrazine and cyanazine with chlorpyrifos were investigated, including changes in uptake and biotransformation rates of chlorpyrifos in the presence of atrazine. Uptake of chlorpyrifos into the worms decreased slightly when atrazine was present in the system, therefore eliminating increased uptake as a possible explanation for the increased toxicity. Body residue analysis of worms indicated increased metabolite formation, suggesting the greater-than-additive response may be due to increased biotransformation to more toxic oxon metabolites.

DNA Damage Induced by Copper on Erythrocytes of Gilthead Sea Bream Sparus aurata and Mollusk Scapharca inaequivalvis by Rosita Gabbianelli; Giulio Lupidi; Milena Villarini; Giancarlo Falcioni (pp. 350-356).

Heavy metal pollution in rivers and its impact on aquatic ecosystems is a dynamic process. Fish are ideal indicators of heavy metal contamination in aquatic systems because they occupy different trophic levels and are of different sizes and ages. In particular, copper is an essential trace metal for living organisms and it is present in all natural waters and sediments. In this paper, we report data on the effect of copper on DNA erythrocytes from the teleost gilthead sea bream Sparus aurata and the bivalve mollusk Scapharca inaequivalvis. In particular, the effect of 0.1 ppm of Cu²⁺ on the nucleated erythrocytes was analyzed using the “comet assay.” This test is a promising tool for estimation of DNA damage at the single cell level. The data obtained show that the in vivo treatment with 0.1 ppm of copper increased the susceptibility of DNA to be damaged. Exposure to Cu²⁺ produces a more evident effect on Sparus aurata, as all three comet parameters significantly increased (tail length, tail intensity, and tail moment). The higher comet parameters measured in Scapharca inaequivalvis compared to Sparus aurata could be due to the difference in stability of the respective hemoglobins. The comet assay could represent a useful test to evaluate the biological consequences of environmental contamination by metals on marine organisms.

Effects of Copper Sulfate on Ion Balance and Growth in Tilapia Larvae (Oreochromis mossambicus) by S. M. Wu; K. J. Jong; S. Y. Kuo (pp. 357-363).

Newly hatched tilapia larvae were exposed to sublethal concentrations of Cu²⁺ (0, 30, 50, and 100 μg/L) and lethal concentrations of Cu²⁺ (200 and 400 μg/L) for 24–96 h. The interaction of the exposure dose and time was related to the Cu²⁺ accumulation rate, which showed a higher accumulation rate with sublethal concentrations of Cu²⁺ within 24 h compared to the other treatments. Furthermore, Cu²⁺ contents in the whole body of larvae significantly increased following Cu²⁺ exposure times up to 96 h. Cu²⁺ in the medium produced a dose-response effect on Na⁺ and K⁺ contents in larvae after 96 h of exposure time. Changes in Ca²⁺ contents statistically significantly decreased and were shown to be dose-responsive for larval exposure times exceeding 72 h. Changes of Ca²⁺ contents were more sensitive than those of Na⁺ and K⁺ with Cu²⁺ treatment of early larvae. Notably Na⁺ and K⁺ contents showed significant increases of 17–23% in larvae exposed to low concentrations of Cu²⁺ (30–50 μg/L) for 24–72 h as compared to control larvae. Cu²⁺ caused no significant effect on body Cl⁻ content or osmolality except at 100 μg/L Cu²⁺ for 24 h in tilapia larvae as compared to the control. However, there was a restoration phenomenon in larvae exposed to 100 μg/L Cu²⁺ for longer than 72 h. The water content of larvae exposed to Cu²⁺ for 96 h significantly decreased. The yolk absorption rate of tilapia larvae was significantly suppressed when they were exposed to Cu²⁺ medium containing 30, 50, 100, 200, or 400 Cu²⁺ μg/L from 72 h post transfer. These results obviously show that larvae are sensitive to Cu²⁺ during early development.

Bioaccumulation of Benzo(a)pyrene from Sediment by Fathead Minnows: Effects of Organic Content, Resuspension and Metabolism by J. F. McCarthy; L. W. Burrus; V. R. Tolbert (pp. 364-370).

The accumulation of ¹⁴C-benzo(a)pyrene (BaP) sorbed to sediment was examined in fathead minnows (Pimephales promelas) to compare uptake from sediment with a high organic carbon (OC) content (7.7%), to that with a low OC content (2%). Ingestion of sediments was quantified by co-labeling the sediment with ¹⁴¹Cerium, which was not assimilated by the fish. Results of this study indicated that (1) significantly greater quantities of BaP were dissolved in water over low-OC sediment, compared to water over high-OC sediment, (2) fish disturbed the sediment and increased the concentration of BaP in centrifuged (particle-free) water, (3) fish ingested significantly more of the low-OC sediment than high-OC sediment, perhaps in response to the lower food quality of the low-OC sediment, and (4) uptake of BaP from sediment ingestion contributed <3% of the total flux of BaP into the fish. Primarily as a result of the greater concentration of BaP in water, fish from the low-OC exposures had significantly higher rates of BaP accumulation. However, after 48 h the body burdens in these fish declined by 50%, likely due to the induction of MFO enzymes in response to accumulation of BaP. A smaller effect was apparent in the fish from the high-OC exposures, consistent with the lower dose of BaP they experienced. These results illustrate the complex, and sometime counterintuitive, interactions that affect the uptake and bioaccumulation of sediment-associated contaminants.

Acetylcholinesterase Activity in Grass Shrimp and Aqueous Pesticide Levels from South Florida Drainage Canals by P. B. Key; M. H. Fulton; J. A. Harman-Fetcho; L. L. McConnell (pp. 371-377).

Freshwater drainage canals in South Florida are utilized to manage water in agricultural, urban, and water conservation areas and, as a result, collect urban and agricultural storm runoff that is discharged into the Atlantic Ocean and Gulf of Mexico. Pesticides in this runoff may be toxic to the biota inhabiting these waters. This study evaluated the effects of contaminants in South Florida canals draining into Biscayne Bay on the estuarine grass shrimp (Palaemonetes intermedius), a representative invertebrate species. Results of surface water analysis for pesticides indicated that eight pesticides out of 52 analyzed were detected. The herbicide metolachlor was found at all nine sites in the five canals sampled at concentrations up to 119 ng/L. Atrazine was detected at seven sites at concentrations up to 29 ng/L. Three organophosphate insecticides (chlorpyrifos, malathion, diazinon) were detected at three sites in two canals (Military and North). Grass shrimp from these three sites showed significantly reduced levels of the acetylcholinesterase enzyme as compared to control shrimp. These two canals are similar in the land use areas drained—urban and suburban and agriculture. The results suggest that monitoring organisms for AChE levels can be a means of detecting exposure to organophosphorus pesticide contamination.

Global Pollution Monitoring of PCBs and Organochlorine Pesticides Using Skipjack Tuna as a Bioindicator by D. Ueno; S. Takahashi; H. Tanaka; A. N. Subramanian; G. Fillmann; H. Nakata; P. K. S. Lam; J. Zheng; M. Muchtar; M. Prudente; K. H. Chung; S. Tanabe (pp. 378-389).

Concentrations of organochlorines (OCs) representing persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs), and hexachlorobenzene (HCB), were determined in the liver of skipjack tuna (Katsuwonus pelamis) collected from the offshore waters of various regions in the world (offshore waters around Japan, Taiwan, Philippines, Indonesia, Seychelles, and Brazil, and the Japan Sea, the East China Sea, the South China Sea, the Bay of Bengal, and the North Pacific Ocean). OCs were detected in livers of all of the skipjack tuna collected from the locations surveyed, supporting the thesis that there is widespread contamination of persistent OCs in the marine environment. Within a location, no significant relationship between growth-stage (body length and weight) and OC concentrations (lipid weight basis) was observed, and the OC residue levels were rather uniform among the individuals. Interestingly, the distribution of OC concentrations in skipjack tuna was similar to those in surface seawaters from which they were taken. These results suggest that OC concentrations in skipjack tuna could reflect the pollution levels in seawater from which they are collected and that this species is a suitable bioindicator for monitoring the global distribution of OCs in offshore waters and the open ocean. Concentrations of PCBs and CHLs in skipjack tuna were higher in offshore waters around Japan (up to 1100 and 250 ng/g lipid wt, respectively), suggesting the presence of sources of PCBs and CHLs in Japan. High concentrations of DDTs and HCHs were observed in samples from the Japan Sea, the East China Sea, the South China Sea, and the Bay of Bengal (up to 1300 and 22 ng/g lipid wt, respectively). This result suggests recent use of technical DDT and HCH for agricultural and/or public health purposes in Russia, China, India, and some other developing Asian countries. Relatively high concentrations of PCBs, CHLs, HCHs, and HCB were also observed in samples collected from some locations in the middle of the Pacific Ocean, indicating the expansion of OC contamination on a global scale. Considering these facts, continuous studies monitoring these compounds in offshore waters and the open seas, using skipjack tuna as a bioindicator, are needed to further understand the future trend of contamination.

Experimental Study of Blood Lead Kinetics in Estuarine Crocodiles (Crocodylus porosus) Exposed to Ingested Lead Shot by K. M. Hammerton; N. Jayasinghe; R. A. Jeffree; R. P. Lim (pp. 390-398).

A previous study of lead (Pb) contamination in estuarine crocodiles (Crocodylus porosus) in Kakadu National Park, Australia, found elevated Pb levels in bone and flesh from individuals caught in habitats where hunting with lead ammunition had occurred. Lead shot was suspected as the potential source of Pb in these animals. An investigation was designed to determine if crocodiles are capable of retaining and dissolving lead shot in their stomachs and absorbing the ionic Pb into the blood. Four of the six juvenile crocodiles (C. porosus) used in the experiment were fed an initial dose of five or ten lead shot each. Most of the lead shot were retained in the stomach over the 20-week experimental period, as confirmed by stomach lavage and radiography of the stomach region. From 13 to 30% of the original weight of individual lead shot had been eroded in that time. In vitro experiments confirmed that lead shot could be dissolved under conditions simulating those known for the crocodilian stomach. Blood Pb concentrations increased by an order of magnitude within a week after dosing three crocodiles with five lead shot each, and then attained steady-state equilibrium 5–20 weeks after dosing, with blood Pb steady-state levels ranging from 278 to 363 μg/dL. The blood Pb concentration–time curves in these crocodiles followed a one-compartment model with first-order loss kinetics that yielded an apparent biological half-life for Pb in blood of about 3.4 days. Throughout the experiment, the crocodiles remained in apparent good physical condition and displayed no clinical signs of Pb toxicosis. These observations, together with the very high blood Pb levels that were sustained for several months, suggest that crocodilians may possess a relatively high degree of resistance to Pb toxicity.

Egrets as Monitors of Trace-Metal Contamination in Wetlands of Pakistan by E. Boncompagni; A. Muhammad; R. Jabeen; E. Orvini; C. Gandini; C. Sanpera; X. Ruiz; M. Fasola (pp. 399-406).

Environments in Pakistan are subject to increasing pollution, but previous studies were very scanty. During 1999 and 2000, we assessed trace element contamination at three wetlands, Karachi Harbour (with presumed industrial-urban pollution), Taunsa Barrage (agricultural pollution), and Haleji Lake (relatively unpolluted), using as indicators the eggs and the feathers of colonial waterbirds, particularly Little Egrets, their prey, and the sediments collected within their foraging areas. The concentrations of As, Cd, Cr, Pb, Hg, Mn, Se, and Zn were generally within the normal background level, and mostly below the threshold that may affect bird survival or reproduction. However, somewhat high concentrations were found in fish from Karachi, for Pb that was at levels that may harm fish reproduction, and for Hg that was at limit concentration for human consumption. Alarming concentrations were found for Cr and Se in sediments from Karachi, that were above the critical levels for contaminated soil, and Se in eggs, that may affect egret reproduction. The differences among the three wetlands were less marked than hypothesized. The egret species within the same area differed in the concentration of certain elements in their eggs, possibly because females may have foraged in different habitats before breeding, whereas no interspecies difference was found in chick feathers, presumably because their food had been collected in similar habitats around the colony. High bioaccumulation from sediments to organic samples occurred for Hg, while Cd, Se, and Zn exhibited low accumulation; for all these elements, feathers of predatory birds such as the egrets are the best indicators of environmental contamination. On the other hand, As and Cr did not bioaccumulate, and the sediments, or the organisms low in the food chain, like fish or crustaceans, are better indicators of their presence in the environment than predatory birds.

Persistent Organochlorine Pollutants in Liver of Birds of Different Trophic Levels from Coastal Areas of Campania, Italy by B. Naso; D. Perrone; M. C. Ferrante; A. Zaccaroni; A. Lucisano (pp. 407-414).

Liver samples of 12 species of birds of different trophic levels, collected during the period 1998–2000 from coastal areas of the Campania region, Southern Italy, were analyzed for organochlorine pesticides (OCs), such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), γ-hexachlorocycloexane (γ-HCH), aldrin, dieldrin, endrin, and the seven PCB “target” congeners, IUPAC Nos. 28, 52, 101, 118, 138, 153 and 180. p,p′-DDE was present in all the samples analyzed, at concentrations ranging from 4 to 4504 ng/g wet wt, which were much higher than those found for HCB, dieldrin, and p,p′-DDD. The concentrations of the others OCs were below the detection limit in all the samples. PCBs were found in all the bird species at levels ranging between 6 and 8431 ng/g wet wt. The hepta-, hexa-, and penta-chlorinated congeners 180, 153, 138, and 118 were predominant since, in almost all the species, they contributed to more than 98% of the total seven determined PCBs. No significant differences in mean concentrations of organochlorine pesticides are detected between single species or between species grouped according to their feeding habits (p > 0.05). However, p,p′-DDE levels were higher in carnivorous species than in omnivorous and insectivorous ones (carnivorous > omnivorous > insectivorous). Concentrations of total PCBs were significantly higher in omnivorous birds than in carnivorous (p < 0.01) and insectivorous ones (p < 0.001), whereas carnivorous birds exhibited significantly higher total PCB levels than insectivorous ones (p < 0.01). Marked differences in total PCB concentrations were found also between single species (from p < 0.05 to p < 0.001). Levels of OCs and PCBs were generally below the thresholds known to affect reproduction, however, mean hepatic concentrations of total PCBs in the yellow-legged herring gull (Larus cachinnans), black-headed gull (Larus ridibundus), and kestrel (Falcus tinnunculus) were far higher than those estimated to elicit immunosuppressive effects and possibly increase susceptibility to parasitoses.

Acute Effects of Vanadate Oligomers on Heart, Kidney, and Liver Histology in the Lusitanian Toadfish (Halobatrachus didactylus) by G. Borges; P. Mendonça; N. Joaquim; J. Coucelo; M. Aureliano (pp. 415-422).

The contribution of vanadate oligomers to the acute histological effects of vanadium was analyzed in the heart, kidney, and liver of Halobatrachus didactylus (Schneider, 1801). A sublethal vanadium dose (5 mM, 1 mL/kg) in the form of metavanadate (containing ortho and metameric species) or in the form of decavanadate (containing only decameric species) was intraperitoneally administered by injection, and specimens of H. didactylus were sacrificed at one and seven days postinjection. Sections of heart ventricle and renal and hepatic tissue were stained with hematoxylin-eosin and examined by light microscopy to identify vanadium-induced tissue injury. In addition, PicroSirius-stained ventricular sections were analyzed by bipolarized light microscopy to determine the fraction of myocardium occupied by the ventricular wall structural elements (collagen I, collagen III, and cardiac muscle). Both vanadate solutions produced similar effects in the renal tissue. Morphological alterations included damaged renal tubules showing disorganized epithelial cells in different states of necrosis. Reabsorbed renal tubules and hyperchromatic interstitial tissue were also observed. The hepatic tissue presented hyperchromatic and hypertrophied nuclei, along with necrotic and hypertrophied hepatocytes, and more severe changes were observed in the liver with exposure to decavanadate. Vanadate oligomers promoted evident tissue lesions in the kidney and liver, but not in the cardiac tissue. However, cardiac tissue structural changes were produced. For example, decavanadate induced a hypertrophy of the ventricle due to a decrease in the percentage of myocardium occupied by collagen fibers. In general, decavanadate was shown to be more toxic than metavanadate.

Effect of Sulfur Dioxide Inhalation on the Glutathione Redox System in Mice and Protective Role of Sea Buckthorn Seed Oil by Dongmei Wu; Ziqiang Meng (pp. 423-428).

This study investigated the effects of sulfur dioxide (SO₂) inhalation and protection by sea buckthorn seed oil from oxidative damage caused by SO₂ in male Kunming-strain mice. One approach was set up to study the effects of SO₂ inhalation on changes of the mice antioxidant defense system. SO₂ at different concentrations (22 ± 2, 64 ± 3, and 148 ± 23 mg/m³) was administered to animals in treatment groups for 7 days, 6 h per day, while control groups were exposed to filtered air under the same condition. The activities of glutathione-S-transferase (GST) and glucose-6-phosphate dehydrogenase (G6PD) and the contents of reduced glutathione (GSH) in brain, lung, heart, liver, and kidney of mice were measured. In the case of inhalation of a SO₂ concentration of 148 ± 23 mg/m³, the activities of GST and G6PD and contents of GSH in the brain, lung, heart, liver, and kidney were significantly decreased. Dose-dependent relations were found between various SO₂-exposed concentrations and the activities of GST and G6PD and the content of GSH. Meanwhile another approach was taken to determine whether sea buckthorn seed oil could maintain the glutathione redox system and prevent the oxidative damage of lung induced by SO₂. In groups given a high dosage (6 or 8 ml/kg) intraperitoneally, the level of TBARS (thiobarbituric acid-reactive substances) was decreased significantly (p < 0.05) by the injection of sea buckthorn seed oil, and the activity of GST was increased significantly (p < 0.05). Overall GST activity and TBARS level exhibited a significant negative correlation (r = 0.891, p < 0.05). The observations showed that SO₂ inhalation resulted in a significant change in the glutathione redox system and indicated that sea buckthorn seed oil could contribute to the antioxidant effects in the case of SO₂ exposure.

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Archives of Environmental Contamination and Toxicology (v.45, #3)