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Archives of Environmental Contamination and Toxicology (v.36, #1)
Algal Toxicity of Antibacterial Agents Applied in Danish Fish Farming by H.-C. Holten Lützhøft; B. Halling-Sørensen; S. E. Jørgensen (pp. 1-6).
Algal toxicity of antibacterial agents applied in fish farming was investigated. The growth-inhibiting effects of amoxicillin (A), flumequine (F), oxolinic acid (OA), oxytetracycline hydrochloride (OT), sarafloxacin hydrochloride (SF), sulfadiazine (SD), and trimethoprim (T) were investigated by a modified test procedure based on the procedure described in the ISO 8692 (1989) protocol on three algal species: the freshwater cyanobacteria Microcystis aeruginosa, the freshwater green alga Selenastrum capricornutum, and the marine cryptophycean Rhodomonas salina. Algal growth was measured as increased chlorophyll concentration by extraction with ethanol followed by measurement of fluorescence. Results were quantified in terms of growth rates using the Weibull equation to describe the concentration response relationship. M. aeruginosa showed higher sensitivity compared to both R. salina and S. capricornutum, whereas the results for the latter two were more or less identical. The toxicity (EC50 value, mg/L) in decreasing order were A (0.0037), SF (0.015), SD (0.135), F (0.159), OA (0.180), OT (0.207), and T (112) for M. aeruginosa; OT (1.6), OA (10), T (16), F (18), SF (24), SD (403), and A (3108) for R. salina; and OT (4.5), F (5.0), SD (7.8), OA (16), SF (16), T (130), and A (NOEC > 250) for S. capricornutum. Applying this test procedure the toxicity of antibacterial agents, being mono- or polyprotic compounds, may be underestimated because of partitioning between ionized and unionized forms.
Action of Inorganic Tin and Organotins on a Hydrocarbon-Using Yeast, Candida maltosa by J. M. Tobin; J. J. Cooney (pp. 7-12).
Two inorganic tin compounds, as well as mono- and tri-substituted methyl-, butyl-, and phenyltins were examined for their interactions with a hydrocarbon-using strain of Candida maltosa. Neither of the inorganic tins (SnII and SnIV) inhibited growth at concentrations up to 0.8 mM while binding to the yeast cells occurred to levels of 0.3 and 0.23 mM Sn/g cells, respectively. Neither inorganic tin caused leakage of potassium from the yeast cells. Among the organotins, tributyl- and triphenyltins caused total viability loss and near maximum potassium loss at initial concentrations of 0.08 mM. For these compounds binding to the cells increased with increasing initial concentrations to maximum values of 0.51 and 0.65 mM Sn/g cells respectively. The other organotin compounds were not inhibitory and did not cause potassium leakage from the cells. Tin from them became cell associated only in the cases of monobutyl- and monophenyl tin, which were bound at markedly lower levels (<0.1 mM Sn/g cells). These results are consistent with the conclusion that the inhibitory compounds can act on the yeast cell membrane but, although binding to the cells is a prerequisite for growth inhibition and cell leakage, no simple correlation was established between binding levels and toxicity effects.
Degradation of Weathered Oil by Mixed Marine Bacteria and the Toxicity of Accumulated Water-Soluble Material to Two Marine Crustacea by M. E. Shelton; P. J. Chapman; S. S. Foss; W. S. Fisher (pp. 13-20).
Artificially weathered crude oil was degraded by four diverse cultures of mixed marine bacteria under optimized conditions for 7 and 14 days. Loss in total weight of starting oil (30 g) ranged from 6.8–17.3% in biologically active incubations compared with only 0.9–1.1% in sterile and nutrient-limited controls. In all incubations, both neutral and acidic water-soluble fractions (WSF) were accumulated. In biologically active systems, 50.9–249.0 mg neutral and 63.3–406.8 mg acidic WSF were accumulated whereas only 6.5–11.1 mg neutral and 1.7–2.2 mg acidic WSF were accumulated in control incubations. Analysis by gas chromatography demonstrated that accumulated WSF in biologically active systems contained compounds different from those washed from the starting crude oil. Exposure of grass shrimp (Palaemonetes pugio) embryos to neutral WSF from each of the biologically active cultures resulted in high embryo mortalities relative to sterile and nutrient-limited controls which exhibited >90% hatching success and larval survival. Toxicity of neutral WSF was also demonstrated on larvae of mysids (Mysidopsis bahia). In both cases, toxicity occurred only on exposure to neutral material accumulated by active, oil-degrading cultures and not with material washed from the weathered crude oil. These results imply that unique compounds were accumulated during degradation that may have been responsible for increased toxicity.
The Use of Bioassays and Toxicity Identification Evaluation (TIE) Procedures to Assess Recovery and Effectiveness of Remedial Activities in a Mine Drainage-Impacted Stream System by L. Deanovic; V. M. Connor; A. W. Knight; K. J. Maier (pp. 21-27).
Effluents from Walker Mine and its tailings pile have resulted in toxic concentrations of metals in Dolly and Little Grizzly Creeks. Recent remedial structures have greatly reduced metal loading, however the need to assess recovery of the receiving aquatic ecosystem exists so that future remediation priorities can be established. The objective was to contribute to this assessment using Toxicity Identification Evaluation procedures. Water samples were collected at several sites in Dolly and Little Grizzly Creeks. Untreated samples and samples passed through ion exchange columns, which remove cationic metals, were compared in side-by-side bioassays using Pimephales promelas, Ceriodaphnia dubia, and Selenastrum capricornutum. Samples were analyzed for total and dissolved copper, cadmium, zinc, and iron. Copper was the element responsible for toxicity. Toxicity was detected in the mine discharge and immediately downstream from the tailings where dissolved copper concentrations were 250 μg/L and 415 μg/L, respectively. Toxicity decreased at downstream sites but extended at least 6.4 km downstream. Improvement in bioassay performance by the treated waters verified metal toxicity. The results indicate that the mine effluent and tailings pile currently have the heaviest impact on Dolly and Little Grizzly Creeks and should be given the highest priority in future remedial programs.
Mechanisms of Cytotoxicity by Cosmetic Ingredients in Sea Urchin Eggs by I. Amouroux; D. Pesando; H. Noël; J.-P. Girard (pp. 28-37).
The acute cytotoxicities of four cosmetic ingredients: a preservative, imidazolidinylurea (IU) and three mild surfactants, cocamido propyl hydroxy sultaine (CAS), magnesium laureth sulfate (Mg LES), and decyl glucoside (APG) were studied using sea urchin eggs. The cellular targets of these compounds were identified by studying the effects on calcium homeostasis, intracellular pH, sodium and potassium contents, protein and DNA synthesis, and protein phosphorylation. These compounds inhibited the first cleavage of sea urchin eggs in a dose-dependent fashion with half maximal doses (IC50) from 30 μg/ml for Mg LES, 60 μg/ml for IU, 83 μg/ml for CAS, to above 400 μg/ml for APG. The time at which a compound showed the greatest toxicity to the cell cycle was definable for APG (between 20 and 50 min postfertilization) and IU (from fertilization to 50 min later); the other compounds being toxic throughout division. Compounds exhibited toxicity to a wide range of cellular targets. IU, the least toxic, mainly operates through inhibition of protein and DNA syntheses. CAS and Mg LES produced nonspecific cytotoxicity related to alterations of membrane and endomembrane permeabilities resulting in ionic disequilibrium (Na+, K+, Ca2+) and inhibition of intracellular storage of Ca2+. The APG effect mainly involved intracellular pH and DNA synthesis, a hypothesis suggested by the narrow postfertilization period of maximal toxicity.
Chronic Toxicity of Ammonia to the Freshwater Bivalve Sphaerium novaezelandiae by C. W. Hickey; M. L. Martin (pp. 38-46).
The chronic toxicity of total ammonium and unionized ammonia (NH3) to the native New Zealand freshwater fingernail clam Sphaerium novaezelandiae was assessed in soft water under laboratory conditions. Control survival after 60 days was high (93%) and concentration-response relationships showed the sensitivity of S. novaezelandiae survival was markedly greater to both total and unionized ammonia (6.4× and 4.6×) after 60 days compared with the 30-day exposure at 20°C. Chronic mortality and number moribund (inability to rebury) showed similar sensitivities, but reproduction was a more sensitive endpoint based on a concentration-response analysis. The survival LC50 values for total and unionized ammonia were 3.8 mg (N)/L (pH 7.5) and 0.037 mg (NH3-N)/L, and reproductive values 0.80 mg (N)/L (pH 7.5) and 0.013 mg (NH3-N)/L at 60 days. No observed effect concentration (NOEC) values for both survival and reproduction were 0.97 mg (N)/L and 0.011 mg (NH3-N)/L, and the lowest observed effect concentration (LOEC) values were 5.4 mg (N)/L and 0.046 mg (NH3-N)/L for survival after 60 days, giving a calculated threshold effect concentration (TEC) of 2.3 mg (N)/L and 0.022 mg (NH3-N)/L. Comparison of the S. novaezelandiae chronic ammonia sensitivity data with the US EPA criteria showed the survival and reproduction TEC values for total ammonia were 1.9× higher than the chronic criterion, and the lethality value 1.4× above the unionized ammonia criterion. The findings suggest that use of the US EPA criteria would provide minimal protection for S. novaezelandiae for chronic ammonia exposure, and that development of site-specific criteria, covering a wide range of environmental conditions, may be required to adequately protect all life stages of this species.
Induction of DNA Strand Breaks and Expression of HSP70 and GRP78 Homolog by Cadmium in the Marine Sponge Suberites domuncula by H. C. Schröder; H. M. A. Hassanein; S. Lauenroth; C. Koziol; T. A.-A. A. Mohamed; M. Lacorn; H. Steinhart; R. Batel; W. E. G. Müller (pp. 47-55).
The marine sponge Suberites domuncula was used as a bioindicator to study the effects of cadmium on the occurrence of DNA strand breakage and on the induction of the expression of the stress biomarkers, heat shock protein 70 (HSP70) and glucose-regulated protein 78 (GRP78) homolog. The cDNA encoding GRP78 homolog from S. domuncula was isolated and characterized. The GRP78 cDNA has a length of 2.1 kb and displays characteristic features of the HSP70 family; it encodes an aa sequence of Mr 72,000. Exposure of S. domuncula to 1 mg/L of cadmium chloride for 24 h caused a strong (16.6-fold) increase in cadmium content to 7.7 μg/g wet weight of sponge tissue; after an incubation period of 6 days, the accumulation was 20.4-fold. The increase in cadmium content was paralleled by a transient decrease in zinc content at days 1 and 3. Exposure of S. domuncula to cadmium chloride also resulted in a marked increase in the number of DNA single strand breaks, as assessed by a recently developed fast and sensitive microplate assay. The maximum increase in DNA damage was observed after an incubation of 12 h in the presence of 1 mg/L of cadmium chloride; after longer incubation, the number of damaged sites decreased, most likely due to DNA repair. Quantitative analysis of the expression of HSP70 (Mr 73 kDa) revealed that onset of maximal levels of HSP70 depends on the concentration of cadmium chloride in the ambient seawater. Maximal induction (8.9-fold increase compared to control) of HSP70 following exposure to 1 mg/L of cadmium chloride was found after 12 h, while longer incubation periods (3–6 days) were needed to reach maximum levels of HSP70 in the presence of lower concentrations of cadmium chloride (0.1 mg/L and 0.01 mg/L). Northern blot analysis revealed that the level of the 2.0 kb sponge GRP78 homolog mRNA transiently increased under cadmium stress; the maximum increase in the presence of 0.1 mg/L of cadmium chloride was observed at day 3. Our results suggest that sponges are useful indicator organisms to assess the genotoxic risks of cadmium pollution in marine environments.
Distribution of Mercury and Other Trace Metals in the Cockle Cerastoderma glaucum from the Mediterranean Lagoon Etang de Thau by P. Szefer; M. Wolowicz; A. Kusak; J.-M. Deslous-Paoli; W. Czarnowski; K. Frelek; M.-J. Belzunce (pp. 56-63).
The concentrations of Ag, Cd, Co, Cr, Cu, Ni, Pb, Zn, Mn, and Fe in the soft tissue of the cockle Cerastoderma glaucum from six sites along the Mediterranean Lagoon Etang de Thau were determined by AAS; Hg was determined by the cold-vapor technique. Significant spatial variations in metal concentrations within the lagoon were recorded. Elevated levels of tissue Pb, Cr, and Hg in the Etang des Eaux Blanches, an area adjacent to the harbor and highly industrialized region, are likely of anthropogenic origin. Seasonally dependent variations in the tissue concentrations of trace elements at Crique de l'Angle were observed. The highest levels of Cr and Pb in the tissue were identified in March 1992, of Hg, Co, and Fe in period August 1990–January 1991, of Mn in August 1992, and Ag in January 1991. The gills contained the maximum amounts of Co and Ni, the mantle the most Fe and Hg, and the digestive gland (hepatopancreas) had most Cu.
The Sublethal Effects and Accumulation of Cadmium in the Terrestrial Isopod Porcellio laevis Latr. (Crustacea, Isopoda) by J. P. Odendaal; A. J. Reinecke (pp. 64-69).
This study investigated the sublethal effects of CdSO4 on the terrestrial isopod species Porcellio laevis and its capacity to accumulate and compartmentalize cadmium. The ability of P. laevis to discriminate between uncontaminated and CdSO4-contaminated leaves was also studied. It was shown that sublethal effects in terms of mass changes of exposed isopods occur at cadmium concentrations between 10 and 80 mg/kg. Moreover, P. laevis can be considered as a so-called macroconcentrator, accumulating and storing cadmium in its hepatopancreas tissue. However, the accumulation capacity is not proportional to the cadmium concentrations in the leaves presented as food, as shown by decreasing concentration factors with increasing cadmium concentrations in the diet. This is probably an effect of the isopod's ability to discriminate between different cadmium concentrations in the food, as shown by means of feed-choice experiments, in which P. laevis was able to avoid contaminated leaves.
Organochlorine Contamination in Bald Eagle Eggs and Nestlings from the Canadian Great Lakes by G. M. Donaldson; J. L. Shutt; P. Hunter (pp. 70-80).
Unhatched eggs and plasma samples from prefledged bald eagles (Haliaeetus leucocephalus) from a recovering population in the Canadian Great Lakes Basin were contaminated with organochlorine compounds at levels comparable to those reported for eagle populations in several areas of the United States. PCBs were among the most commonly detected contaminants and occurred at high concentrations in plasma. Plasma PCB concentrations in Lake Erie nestlings were significantly higher than in chicks from Lake Nipigon (0.130 and 0.047 mg/kg wet weight, respectively). Blood levels of mirex were higher in nestlings from Lake Superior compared to those from Lake Erie (0.0012 and 0.0006 mg/kg wet weight, respectively). Migration routes and over-winter locations of avian prey that constitute a part of the bald eagle chick's diet are likely to contribute to these spatial contaminant patterns in plasma. Atmospheric deposition and a cold condensation effect for chlordane compounds may have produced higher levels of these compounds in plasma samples from Lake Superior compared to samples from Lake Erie (0.020 and 0.008 mg/kg wet weight, respectively). Levels of DDE in plasma were generally low, ranging in concentration from 0.02 mg/kg wet weight for lakes Erie and Nipigon to 0.06 mg/kg wet weight for Lake Huron. Concentrations of organochlorines in eaglet plasma remained relatively stable between 1990 and 1996; no significant trends associated with year of sampling were detected. The data from Lake Erie showed no correlation between productivity and plasma levels of PCBs or DDE during this time period. There were no indications that the concentrations of contaminants detected were adversely affecting productivity in Canadian Great Lakes bald eagle populations. Residue levels in eggs from Lake Erie eagle territories were equally or more contaminated than eggs from other highly contaminated environments in the United States such as the Great Lakes and Columbia River estuary. Concentrations of DDE and PCBs in Lake Erie eggs declined significantly between 1974 and 1994. Although dieldrin and chlordane levels showed a similar decline, these relationships were not statistically significant. Mirex concentrations were relatively stable. Eggs from Lake of the Woods were significantly less contaminated than those from Lake Erie (PCBs: 3 and 84 mg/kg wet weight, respectively; DDE: 3 and 24 mg/kg wet weight, respectively). Reproductive success (number of young produced/active nest) remained constant between 1982 and 1996 and productivity is sufficient to maintain an increasing population. The number of active nests has increased during this period indicating that the population is expanding and might be expected to do so until suitable habitat becomes limiting. Reductions in organochlorine levels, reintroduction efforts, immigration from other populations, and changes in habitat quality have likely contributed to the observed growth in the number of breeding pairs.
Vanadium Accumulation in Pinnipeds by K. Saeki; M. Nakajima; K. Noda; T. R. Loughlin; N. Baba; M. Kiyota; R. Tatsukawa; D. G. Calkins (pp. 81-86).
Vanadium in four species of pinnipeds (northern fur seals [Callorhinus ursinus], Steller sea lions [Eumetopias jubatus], harbor seals [Phoca vitulina], and ribbon seals [Phoca fasciata]) caught in the Northern Pacific was analyzed using ICP-MS to understand its accumulation and distribution. In northern fur seals, relatively high concentrations of vanadium were observed in the liver, hair, and bone. Ninety percent of the vanadium burden in the body was concentrated in these three tissues, which comprise <20% of total body weight. Hepatic vanadium concentrations in the four pinniped species were significantly correlated to age, although the levels varied with species. An increase in vanadium accumulation in the liver of northern fur seals was caused by an increase of retention in nuclei and mitochondria fraction in the cells. Vanadium concentrations in liver were significantly correlated with mercury, silver, and selenium concentrations in northern fur seals, Steller sea lions, and harbor seals.
Comparison of Elements in Bottlenose Dolphins Stranded on the Beaches of Texas and Florida in the Gulf of Mexico over a One-Year Period by J. P. Meador; D. Ernest; A. A. Hohn; K. Tilbury; J. Gorzelany; G. Worthy; J. E. Stein (pp. 87-98).
We analyzed tissue samples from bottlenose dolphins (Tursiops truncatus) that had stranded on beaches in Texas and Florida over a 1-year period starting in September 1991. The concentrations of 10 elements plus methyl mercury (MeHg) were determined in brain, kidney, and liver, and we examined these results for differences based upon age, site, sex, and tissue type. A strong inverse relationship between total mercury (Hg) and the percentage that was MeHg was found in liver, kidney, and brain tissue, presumably due to demethylation of MeHg. A threshold concentration was found for total Hg in brain tissue, indicating that most Hg was present as MeHg up to about 8 years of age. Increases in total Hg after this age were accompanied by an increase in the ratio of total Hg to MeHg, indicating demethylation. Strong relationships were found between total Hg in liver and age and between total Hg and selenium in liver, which have been observed before in many fish- and squid-eating marine mammals. The only difference based on sex of the animals was observed for MeHg, which was higher in females and contrary to the pattern often observed for organic contaminants. Several elements (copper, Hg, lead, zinc) exhibited intersite differences, which were not consistent. Bottlenose dolphin from Florida exhibited the highest levels of MeHg and total Hg, while animals from Texas exhibited the highest levels of lead, copper, and zinc. The essential elements copper and zinc were expected to be the same for the Texas and Florida animals; however, observed differences may indicate population differences in basic physiological levels, dietary intake, or health status.
A Study for the Proper Application of Urinary Naphthols, New Biomarkers for Airborne Polycyclic Aromatic Hydrocarbons by M. Yang; M. Koga; T. Katoh; T. Kawamoto (pp. 99-108).
Urinary naphthols, 1- and 2-naphthol, recently have been suggested as route-specific biomarkers for exposure to airborne polycyclic aromatic hydrocarbons. For the proper application of urinary naphthols as biomarkers, we studied effects of lifestyle on urinary naphthols levels in 119 Japanese male workers. After improving the detection limit of urinary naphthols up to 0.27 μg/L by high-resolution capillary gas chromatography/mass spectrometry/selected ion monitoring, urinary naphthols were detectable in approximately 90% of the subjects. Among detectable samples, the geometrical mean (GM) of urinary 1-naphthol concentration was 5.13 μg/L (geometrical standard deviation, GSD, 4.90), while the GM of urinary 2-naphthol concentration was 3.16 μg/L (GSD, 5.61). We observed that urinary 1- and 2-naphthol level were three- and sevenfold higher, respectively, among smokers than among nonsmokers (p < 0.01). The ratios of urinary 2-naphthol to 1-naphthol were significantly higher among smokers than nonsmokers (p < 0.05). The number of cigarettes smoked and urinary cotinine levels were also positively related to the concentration of urinary naphthols (p < 0.01), while other lifestyle factors, i.e., age and consumption of alcohol, greasy or salty food, sweets, fruits, vegetables, meat, or fish, were not. We also studied whether genetic polymorphisms of enzymes, which were involved in naphthalene metabolism, affected urinary naphthols levels. The cytochrome P450 (CYP) 1A1 exon 7 genetic polymorphism was not related to urinary naphthol levels. Among smokers, the subjects with c1/c2 or c2/c2 type of CYP2E1, which was determined by CYP2E1 RsaI polymorphism in 5′-flaking region, showed higher concentrations of urinary 2-naphthol than the subjects with c1/c1 type regardless of creatinine-correction (p < 0.05) and the subjects with glutathione S-transferase (GST) M1 deficient type showed higher concentrations of both urinary 1- and 2-naphthol than those with GSTM1 normal type but only without creatinine-correction (p < 0.05). Thus, when urinary naphthols are used as biomarkers, smoking and the genetic polymorphisms of CYP2E1 and GSTM1 should be considered.