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Archives of Environmental Contamination and Toxicology (v.41, #4)
Antioxidant Effect of Taurine Against Lead-Induced Oxidative Stress by H. Gürer; H. Özgünes; E. Saygin; N. Ercal (pp. 397-402).
Oxidative stress is proposed as a molecular mechanism in lead toxicity, which suggests that antioxidants might play a role in the treatment of lead poisoning. The present study was designed to investigate whether taurine has a beneficial effect both on Chinese hamster ovary (CHO) cells and on Fisher 344 (F344) rats following lead exposure. Therefore, oxidative stress parameters (glutathione, malondialdehyde levels, catalase, and glucose-6-phosphate dehydrogenase [G6PD] activities) of lead-exposed CHO cells and F344 rats were determined following taurine treatment. Taurine was found to be effective in (1) increasing glutathione levels that had been diminished by lead; (2) reducing malondialdehyde levels, an end-product of lipid peroxidation; (3) decreasing catalase and erythrocyte G6PD activity, which had been increased by lead exposure; and (4) improving cell survival of CHO cells. However, taurine had no effect on blood and tissue lead levels when 1.1 g/kg/day taurine was administered to F344 rats for 7 days, following 5 weeks of lead exposure (2,000 ppm lead acetate). As a result, taurine seems to be capable of fortifying cells against lead-induced oxidative attack without decreasing lead levels. Therefore, administration of taurine, accompanied by a chelating agent, might increase its effectiveness in the treatment of lead poisoning.
Protective Effects of Selenium Against Mercury Toxicity in Cultured Atlantic Spotted Dolphin (Stenella plagiodon) Renal Cells by A. Wang; D. Barber; C. J. Pfeiffer (pp. 403-409).
Marine mammals are known for their low susceptibility to mercury toxicity, and selenium may play a role in this protection against mercury intoxication. To gain insight into mechanisms by which selenium might inhibit mercury toxicity in cetacean cells, we investigated the effects of sodium selenite on cell proliferation and cell death (including apoptosis, oncosis, and necrosis) of control and mercuric chloride–treated Atlantic spotted dolphin renal cells (Sp1K cells). Concurrent exposure to 80 μM Na2SeO3 provided full protection against the decrease in cell proliferation induced by 20 μM HgCl2. Pretreatment with Na2SeO3 increased the protective effects of selenium administered later in conjunction with mercury, but pretreatment alone did not provide protection against mercury given alone. Furthermore, Na2SeO3 administered after the exposure to HgCl2 did not protect cells. These data suggest that the coexistence of Na2SeO3 and HgCl2 was essential for the protective effects of Na2SeO3 against the toxicity of HgCl2 in Sp1K cells, and may involve selenium–mercury binding. This is supported by the results of an experiment in which earlier premixed mercury and selenium solutions were less cytotoxic than freshly mixed solutions. Furthermore, HgCl2 induced apoptosis in Sp1K cells, as revealed by nuclear specific dye (7-AAD) incorporation and cell flow cytometry, and this was prevented by the concurrent exposure to Na2SeO3. Inhibition of mercury-induced apoptosis in marine mammal cells, provided by selenium, may contribute to the in vivo protection. This study is the first report that addresses the mechanism of mercury–selenium antagonism in cultured cetacean cells at the cellular level.
The Occurrence and Distribution of Selected Trace Elements in the Upper Rio Grande and Tributaries in Colorado and Northern New Mexico by H. E. Taylor; R. C. Antweiler; D. A. Roth; T. I. Brinton; D. B. Peart; D. F. Healy (pp. 410-426).
Two sampling trips were undertaken in 1994 to determine the distribution of trace elements in the Upper Rio Grande and several of its tributaries. Water discharges decreased in the main stem of the Rio Grande from June to September, whereas dissolved concentrations of trace elements generally increased. This is attributed to dilution of base flow from snowmelt runoff in the June samples.Of the three major mining districts (Creede, Summitville, and Red River) in the Upper Rio Grande drainage basin, only the Creede District appears to impact the Rio Grande in a significant manner, with both waters and sediments having elevated concentrations of some trace elements considerably downriver. For example, dissolved zinc concentrations upriver of Willow Creek, which primarily drains the Creede District, were about 2–3 μg/L; immediately downstream of the Willow Creek confluence, concentrations were above 20 μg/L; and elevated concentrations occurred in the Rio Grande for the next 100 km. The Red River District does not significantly impact the Upper Rio Grande for most trace elements. Because of current water management practices, it is difficult to assess the impact of the Summitville District on the Upper Rio Grande.There are, however, large increases in many dissolved trace element concentrations as the Rio Grande passes through the San Luis Valley, coincident with elevated concentrations of those same trace elements in tributaries. Among these elements are As, B, Cr, Li, Mn, Mo, Ni, Sr, U, and V.None of the trace elements exceeded U.S. EPA primary drinking water standards in either survey, with the exception of cadmium in Willow Creek. Secondary drinking water standards were frequently violated, especially in tributaries draining areas where mining has occurred. Dissolved zinc (in Willow Creek in both June and September) was the only element that exceeded the EPA Water Quality Criteria for aquatic life of 120 μg/L.
Application of the Sequential Elution Technique to Determine Cd and Cu Cellular Location in Ulva lactuca Linnaeus by R. C. Costas; J. López (pp. 427-435).
The sequential elution technique, used to determine the cellular location of metals in nonvascular plants, was adapted to the seaweed Ulva lactuca Linnaeus for the heavy metals Cu and Cd. The optimum conditions for the extraction of extracellular Cu and Cd were determined using specimens previously loaded with these metals. The best extracellular metal extraction media and the number of extracellular metal extraction steps obtained were the following: Two steps (1 h + 40 min) in a filtered sea water–20 mM Ni solution for Cd and two steps in a filtered sea water–50 mM Co solution for Cu. To find these extraction conditions the extracellular metal extraction capacity of the different media used as well as the alteration provoked in plasmalemma permeability were compared. The concentrations of the incubation solutions of Cd and Cu that allowed reliable comparisons between the different extracellular metal extraction media used were previously determined.
Modification, by the Insecticide Chlorpyrifos, of the Behavioral Response to Kairomones of a Parasitoid Wasp, Leptopilina boulardi by N. Komeza; P. Fouillet; M. Boulétreau; J. M. Delpuech (pp. 436-442).
Parasitoids are key species involved in the regulation of natural populations. Host parasitization is realized via some important steps in which kairomone perception is essential. Due to the wide use of insecticides and their contribution to environmental pollution, the determination of their sublethal effects on behaviors involved in the reproduction of parasitoids becomes a necessity. In this work, we analyzed the effects of a lethal dose 20% of chlorpyrifos, an organophosphorus insecticide, on the behavior of L. boulardi toward the kairomone of its host. The insecticide significantly modified the kinetics of the residence time of parasitoids on a patch marked by kairomones. Females exposed to the insecticide were less efficient in finding the kairomone patch than control females, and they tended to stay on that patch, whereas control females rapidly left it. These effects are discussed considering the mode of action of the insecticide. Because search time allocation of host is an important component for parasitism efficiency, this modification of behavior could interfere with the reproduction capacity of parasitoids. Therefore, in a context of environmental pollution, the repercussions of such sublethal effects on the population biology of insects need to be considered.
Chlorpyrifos-Induced hsp70 Expression and Effect on Reproductive Performance in Transgenic Drosophila melanogaster (hsp70-lacZ) Bg 9 by A. Nazir; I. Mukhopadhyay; D. K. Saxena; D. Kar Chowdhuri (pp. 443-449).
Expression of hsp70 in the third-instar larval tissues of transgenic Drosophila melanogaster (hsp70-lacZ) following dietary exposure to organophosphate insecticide chlorpyrifos for various time intervals was investigated. Effect of the chemical on different developmental stages of the fly was also evaluated by looking at survivorship, hatchability, emergence, fecundity, fertility, and reproductive performance. Our results showed that the toxicant evokes profound cytotoxic effect as evidenced by dark blue staining in salivary gland, proventriculus, brain ganglia, and midgut in the lowest concentration of the chemical following 24 and 48 h of exposure. On the other hand, a significant increase (61%) in hsp70 expression in the above larval tissues was observed in the next higher concentration of the toxicant after 6 h exposure when compared with that of the lowest dose. A further increase in exposure time caused 100% larval mortality. Similarly, larvae exposed to higher concentrations of the toxicant, exhibited 100% mortality within 1 h of treatment. The insecticide caused a delay in emergence and a severe reduction in survivorship of the flies in a dose-dependent manner with 100% mortality within a day of exposure in the highest dosed group. A delay in emergence by 3 days was evident even in the lowest concentration of the chemical. A drastic effect of the chemical on hatchability was found in the highest dosed group with 100% embryonic mortality at post-16 stage of the embryo. Reproductive performance was significantly affected even in the lowest dosed group. The present study suggests that certain larval tissues of Drosophila, a nontarget organism, are vulnerable to chlorpyrifos as evidenced by hsp70 expression. Further, the adverse effect of the toxicant is reflected on various stages of development of the fly including reproductive performance.
Toxicokinetics, Available Source, and Route of Entry of Lead in Fed and Food-Deprived Bullfrog (Rana catesbeiana) Larvae by T. M. Rice; J. T. Oris; D. H. Taylor (pp. 450-457).
Several toxic effects of lead (Pb) have been documented in amphibians, but few studies have measured tissue levels of exposed specimens or examined toxicokinetics, availability of dietary versus waterborne sources, or route of entry. We modeled the toxicokinetics and examined the availability of dietary and waterborne Pb in both fed and food-deprived bullfrog (Rana catesbeiana) larvae. Uptake rates of Pb (1,000 μg Pb/L nominal exposure) were similar between fed and unfed larvae, but unfed larvae eliminated Pb slowly. Consequently, food-deprived larvae accumulated significantly more Pb compared to fed larvae. The intestinal tract contained > 90% of total body Pb in both fed and unfed larvae. Total body concentrations of Pb in fed larvae did not increase over 7 days although levels in food did increase. We concluded that food consumption influenced Pb accumulation through changes in elimination rates rather than in uptake rates. Pb appeared to enter the body of larvae through ingestion of contaminated water rather than food.
Reproductive Effects of Ethynylestradiol and 4t-Octylphenol on the Zebrafish (Danio rerio) by K. Van den Belt; R. Verheyen; H. Witters (pp. 458-467).
In this study, the impact of ethynylestradiol (EE2) and 4t-octylphenol (OP) on reproduction in zebrafish (Danio rerio) was evaluated using spawning and fertilization success, gonadosomatic index, and plasma vitellogenin (VTG) levels as endpoints. Adult male and female zebrafish were exposed under semi-static conditions to 5, 10, 25 and 50 ng/L EE2 and to 12.5, 25, 50 and 100 μg/L OP for 3 weeks. A dose-related reduction in the number of females capable of spawning was observed at 10 ng/L EE2 with a complete inhibition of spawning at levels of 25 ng/L EE2. The ovaries of these nonspawning females were regressed and mean ovary somatic index (OSI) was significantly below the reference OSI determined in nonexposed females prior to spawning. Our results suggest an adverse impact of EE2 on male fertilization capacity and demonstrate a significant reduction in testis somatical index after exposure to 10 and 25 ng/L EE2. For both males and females, a dose dependent VTG induction was measured. Levels of VTG in fish plasma were significantly correlated with measured gonadosomatic indices. Minor effects were observed for OP. No significant effects on spawning or fertilization success were observed in this study, though OSI of nonspawning females was reduced at levels of 25 μg/L OP and higher. No changes in plasma protein levels were measured in male and female fish exposed to OP. The results from this study demonstrate that OP and especially EE2 can adversely affect the normal reproduction success of male and especially female zebrafish, with relevance for population effects.
Tissue-Specific Cadmium Accumulation, Metallothionein Induction, and Tissue Zinc and Copper Levels During Chronic Sublethal Cadmium Exposure in Juvenile Rainbow Trout by L. Hollis; C. Hogstrand; C. M. Wood (pp. 468-474).
Juvenile rainbow trout, on 3% of body weight daily ration, were exposed to 0 (control) or 3 μg/L Cd (as Cd(NO3)2· 4H2O) in moderately hard (140 mg/L as CaCO3), alkaline (95 mg/L as CaCO3, pH 8.0) water for 30 days. Particular attention focused on Cd burden in tissues (gills, liver, kidney, and whole body) and induction of metallothionein (MT) in gills, liver, and kidney during chronic Cd exposure. Mortality in Cd-exposed fish was minimal (∼10%), and no growth effects occurred over the 30-day exposure. Cd accumulated in a time-dependent fashion to 9 times (gills), 3 times (liver), 20 times (kidney), 2 times (carcass), and 2 times (whole body) control levels by 30 days; absolute concentrations were in the order kidney > gill > liver > whole body > carcass. Tissue (gills, liver, and kidney) Zn and Cu burdens were not altered by chronic exposure to 3 μg/L Cd. MT concentrations in all tissues increased over the 30 days of Cd exposure, but the increases were much less than those of Cd on a molar binding site basis. Absolute MT concentrations were in the order liver > kidney > gill, but relative increases were greatest in kidney (fourfold), followed by gills (twofold) and liver (1.3-fold). MT levels were sufficient to bind all Cd in gill, liver, and kidney under control conditions, and after chronic Cd exposure remained sufficient in liver and kidney, but not in gills. Total metal levels (Cd + Zn + Cu) greatly exceeded MT binding capacity in all tissues under all conditions.
Assessment of Reproductive Effects in Largemouth Bass (Micropterus salmoides) Exposed to Bleached/Unbleached Kraft Mill Effluents by M. S. Sepúlveda; D. S. Ruessler; N. D. Denslow; S. E. Holm; T. R. Schoeb; T. S. Gross (pp. 475-482).
This study evaluated the potential effects of different concentrations of bleached/unbleached kraft mill effluent (B/UKME) on several reproductive endpoints in adult largemouth bass (Micropterus salmoides). The kraft mill studied produces a 50/50 mix of bleached/unbleached market pulp with an estimated release of 36 million gal of effluent/day. Bleaching sequences were C90d10EopHDp and CEHD for softwood (pines) and hardwoods (mainly tupelo, gums, magnolia, and water oaks), respectively. Bass were exposed to different effluent concentrations (0 [controls, exposed to well water], 10, 20, 40, or 80%) for either 28 or 56 days. At the end of each exposure period, fish were euthanized, gonads collected for histological evaluation and determination of gonadosomatic index (GSI), and plasma was analyzed for 17β-estradiol, 11-ketotestosterone, and vitellogenin (VTG). Largemouth bass exposed to B/UKME responded with changes at the biochemical level (decline in sex steroids in both sexes and VTG in females) that were usually translated into tissue/organ-level responses (declines in GSI in both sexes and in ovarian development in females). Although most of these responses occurred after exposing fish to 40% B/UKME concentrations or greater, some were observed after exposures to 20% B/UKME. These threshold concentrations fall within the 60% average yearly concentration of effluent that exists in the stream near the point of discharge (Rice Creek), but are above the <10% effluent concentration present in the St. Johns River. The chemical(s) responsible for such changes as well as their mode(s) of action remain unknown at this time.
Multi-Elemental Concentrations in Tissues of Japanese Common Squid (Todarodes pacificus) by H. Ichihashi; Y. Nakamura; K. Kannan; A. Tsumura; S. Yamasaki (pp. 483-490).
Forty-five elements were determined in mantle muscle and liver of juvenile Japanese common squid, Todarodes pacificus, collected from three locations in and near Japanese coasts, using a high-resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) and an inductively coupled plasma atomic emission spectroscope (ICP-AES). Multivariate statistical techniques were applied to discriminate populations of squids from these three locations by treating absolute and relative concentrations of trace elements. Significant differences were found in the concentrations of elements, particularly for some alkaline and alkaline earth elements in the muscle and liver and for some 3d transition elements in the liver of three groups of squids. Squids from the Pacific Ocean could be distinguished from those of the Sea of Japan by discriminant function analysis of elemental concentrations. Based on the analysis, the squids collected from the Nemuro Strait in Japan were predicted to belong to those from the Sea of Japan. Elemental concentrations and discriminant function analysis can be used to identify subpopulations and migratory routes of squids.
Trace Elements in King Eiders and Common Eiders in the Canadian Arctic by M. Wayland; H. G. Gilchrist; D. L. Dickson; T. Bollinger; C. James; R. A. Carreno; J. Keating (pp. 491-500).
We determined concentrations of selected trace elements in tissues of king and common eiders at three locations in the Canadian arctic. Renal and hepatic cadmium concentrations in king eiders at a location in the eastern arctic were among the highest ever recorded in eider ducks: there, they were higher in king eiders than in common eiders. Cadmium concentrations were lower in king eiders from the western arctic than in those from the east. In the western arctic, cadmium concentrations did not differ between species. Hepatic mercury and zinc were higher in king eiders than in common eiders. Zinc and selenium were higher in eiders from the western arctic than in those from the eastern arctic. Trace element concentrations in these two duck species were below published toxicity thresholds. Positive correlations in trace element concentrations in both species were found between total and organic hepatic mercury, renal and hepatic cadmium as well as hepatic zinc, copper, mercury, and cadmium. Body mass of common but not king eiders and spleen mass of both species were negatively correlated with mercury concentrations. In common eiders, the number of nematode parasites was positively correlated with total and organic mercury. Histopathological evidence of kidney or liver lesions that are typical of trace metal poisoning was not found. We did not find evidence to support the hypothesis that trace metal exposure may be contributing to adverse effects on the health of individuals of these species.
Mercury in Eggs and Feathers of Great Egrets (Ardea albus) from the Florida Everglades by D. G. Rumbold; S. L. Niemczyk; L. E. Fink; T. Chandrasekhar; B. Harkanson; K. A. Laine (pp. 501-507).
Great egret (Ardea albus) eggs and nestling feathers were collected for total mercury (THg) and methylmercury (MeHg) analysis from two colonies in the Florida Everglades in 1999 and 2000. THg was present in all eggs at a mean concentration of 0.39 ± 0.19 μg/g fresh weight (n = 33, range = 0.08–0.86 μg/g). Egg-THg levels did not differ significantly between colonies or years. MeHg concentration in eggs was 0.35 ± 0.18 μg/g fresh weight (n = 20, range = 0.05–0.82 μg/g,), and on average represented 85% of the THg found in the egg. Concentration of THg in feathers from egret nestlings, age 11–31 days, ranged from 1.4 to 8.6 μg/g dry weight. Feather-THg levels also did not differ significantly between colonies or years. THg concentrations in feathers, normalized based on bill length, were positively correlated to THg concentrations in eggs from the same clutch. Levels of THg in both eggs and feathers were lower in 1999 and 2000 than values reported for similar samples collected in 1993–95, indicating that MeHg exposure has decreased in the southern Everglades since the mid-1990s. THg levels in eggs and nestling feathers for the period of this study were below levels associated with toxic reproductive effects. Clutch size, fledging success, and brood size observed in this study were consistent for this species in the Everglades. Collectively, these results suggest that MeHg was not adversely affecting the reproductive performance of this population during the study.
Uptake and Distribution of Three PCB Congeners and Endosulfan by Developing White Leghorn Chicken Embryos (Gallus domesticus) by T. A. Bargar; G. I. Scott; G. P. Cobb (pp. 508-514).
The distributions of PCB 105, 156, 189, and endosulfan in incubating, maternally exposed, viable white leghorn chicken eggs (Gallus domesticus) were investigated. Hens were subcutaneously injected every 4 days with a mixture of the above chemicals. One group of five eggs was removed from the incubator at each of 9, 14, and 19 days of incubation; dissected into three compartments (embryo, chorioallantoic membrane, and yolk + albumin); weighed; frozen; and then later analyzed for the dosing chemicals. Through 19 days of development (90% of incubation), greater than 70% of the total chemical mass in the whole egg remained within the yolk + albumin, whereas, depending on the chemical, 17% to 30% was absorbed by the embryo and 0.2% to 9% was transported into the chorioallantoic membrane. As a percentage of total PCB mass within the respective compartment, PCB 105 composition in the embryo and chorioallantoic membrane decreased significantly throughout development while PCB 156 and 189 composition increased significantly throughout development. Though endosulfan composition within any of the compartments was highly variable, it did not change significantly during development. The results of this study indicate that the majority of avian chick exposure to contaminants occurs posthatch as the chick continues to utilize the residual yolk.
Developmental Instability in a Riparian Population of the Algerian Mouse(Mus spretus) Associated with a Heavy Metal–Polluted Area in Central Portugal by A. C. Nunes; J.-C. Auffray; M. L. Mathias (pp. 515-521).
The adverse effects of heavy metals (mostly Cr, Mn, Fe, Cu, Zn, and Se) on the environment were appraised by comparing fluctuating asymmetry of dental characters (molars) in Algerian mice (Mus spretus) from polluted (Oeiras) and reference (Xévora) riparian areas, in central Portugal. The size of tooth traits was shown to be reduced in the contaminated area, and the developmental instability increased. The results suggest that Algerian mice may be used as indicators of heavy metal pollution and that fluctuating asymmetry represents a useful tool for monitoring ecological stresses, even when the contamination levels are low.
Evaluation of the Toxic Potentials of Cypermethrin Pesticide on Some Reproductive and Fertility Parameters in the Male Rats by A. Elbetieha; S. I. Da'as; W. Khamas; H. Darmani (pp. 522-528).
Adult male Sprague-Dawley rats were exposed to tap water containing 0, 8,571, 17,143, or 34,286 ppm cypermethrin for 12 weeks. Based on water consumption per animal per day the rats received 13.15, 18.93, and 39.66 mg cypermethrin, respectively. Fertility was significantly reduced in male rats ingesting cypermethrin at a concentration of 13.15 and 18.93 mg in that the number of females impregnated by them was significantly reduced. The number of implantation sites was significantly reduced in females mated with males that had ingested cypermethrin at a concentration of 39.66 mg. A significant reduction in the number of viable fetuses was observed in females impregnated by the exposed males at all three doses of cypermethrin.The body weight gain was significantly lower in the treated males. Ingestion of cypermethrin at a concentration of 18.93 or 39.66 mg per day resulted in a significant increase in the weights of testes and seminal vesicles. Preputial gland weights were increased at all three concentrations of cypermethrin. Epididymal and testicular sperm counts as well as daily sperm production were significantly decreased in exposed males. The serum levels of testosterone, follicle-stimulating hormone and luteinizing hormone were significantly reduced in males exposed to 39.66 mg per day.Ingestion of cypermethrin at 18.93 and 39.66 mg/animal/day also resulted in a significant decrease in the perimeter and number of cell layers of the seminiferous tubules. The testes of treated animals were infiltrated with congested blood vessels with marked hemorrhage and a significant accumulation of connective tissue surrounding the seminiferous tubules, which contained a large number of immature spermatids. These results clearly demonstrate the adverse effects of cypermethrin pesticide on fertility and reproduction in male rats.
Effects of Exposure Time, Material Type, and Granular Pesticide on Glove Contamination by C. Guo; J. Stone; H. M. Stahr; M. Shelley (pp. 529-536).
Chemical-resistant gloves are recommended for pesticide applicators to reduce their exposure to agricultural chemicals. In this research, three chemical-resistant glove materials—nitrile, neoprene, and barrier laminate—were studied in relation to contamination with granular terbufos and tefluthrin. Surfaces of specimens backed with alpha cellulose were contaminated with 300 mg of either granular terbufos or tefluthrin for 1-, 2-, 4-, 8-, 16-, and 24-h time periods in petri dishes in the laboratory. Residues were extracted using ethyl acetate for terbufos and iso-octane for tefluthrin in test tubes for 24 h. Analysis of extracts by gas chromatograph and statistical analysis of the data showed that contamination levels varied with the time of exposure, material type, and pesticide used. Pesticide was not detected in the alpha cellulose even after 24 h contamination time. A linear relationship was found between contamination level and exposure time for terbufos in the three materials, with longer exposure times causing higher contamination levels. Contamination of nitrile was significantly less than neoprene or barrier laminate. Exposed glove materials contained higher levels of contamination of terbufos than tefluthrin.