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Archives of Environmental Contamination and Toxicology (v.36, #2)
A Simple Comparison of Mass Spectral Search Results and Implications for Environmental Screening Analyses by R. A. Silva-Wilkinson; L. P. Burkhard; B. R. Sheedy; G. M. DeGraeve; R. A. Lordo (pp. 109-114).
A simple assessment of the ability of environmental laboratories to perform automated library searching procedures on mass spectra of unknown pollutants was conducted. In this assessment, 10 laboratories analyzed a hexane solution containing eight organic chemicals using gas chromatography/mass spectrometry and searched their acquired mass spectral data against mass spectral reference libraries. The search results were used to evaluate the similarity of the lists of tentative identifications (TIDs) among the laboratories and to compare the observed searching success to the searching success reported in the literature using high-quality mass spectral data. A high degree of similarity was observed among the lists of TIDs reported by the laboratories for each chemical. The searching success observed in this study was slightly lower than that reported in the literature based on higher-quality mass spectral data. This simple comparison suggests that laboratories performing routine environmental analyses can successfully perform automated searching procedures for unknown sample components, and that the mass spectral searching component of analytical methods designed to screen for unknown organic pollutants should be successful, i.e., obtain similar and reproducible results among laboratories.
Primary DNA Damage But Not Mutagenicity Correlates with Ciprofloxacin Concentrations in German Hospital Wastewaters by A. Hartmann; E. M. Golet; S. Gartiser; A. C. Alder; T. Koller; R. M. Widmer (pp. 115-119).
Recently, we showed for the wastewater of a large Swiss university hospital that primary DNA damage, assessed by a bacterial SOS repair assay (umuC test), could be largely assigned to a specific class of antibiotics, the fluoroquinolones (FQs) (Hartmann et al.[1998] Environ Toxicol Chem 17:377–382). In an attempt to confirm the significance of FQs for the bacterial DNA damaging effects in native hospital wastewaters, 25 samples from five German clinics were screened in this study by the umuC test. The results were compared to HPLC-derived concentrations of ciprofloxacin, an important member of the FQs. Ten samples (40%) were umuC-positive and ciprofloxacin concentrations ranged from 0.7 to 124.5 μg/L (n = 24). Primary DNA damage, as indicated by the umuC test, correlated strongly with ciprofloxacin concentrations in a logistic, dose-dependent manner (r2 = 0.896), almost irrespective of the use of S9 metabolic activation. The lowest observed effect concentration (LOEC) for ciprofloxacin was 5.2 μg/L (+S9) and 5.9 μg/L (−S9). Similar to our previous findings, these results indicate that positive umuC results in hospital wastewater are strongly dependent on the presence of fluoroquinolone antibiotics. In a second part of the study, previously generated Ames and V79 chromosomal aberration data of the same samples (Gartiser and Brinker [1995] in Umweltbundesamt Texte 74/95) were compared with the newly generated results. Neither the mutagenic effects detected by the Ames assay (8%, n = 25) nor the positive V79 results (46% n = 13) seemed to be caused by ciprofloxacin. Therefore, the Ames and V79 results suggest the presence of additional mutagens that are yet to be identified.
Copper Bioavailability in Steilacoom Lake Sediments by D. B. Huggett; W. B. Gillespie Jr.; J. H. Rodgers Jr. (pp. 120-123).
Sediments were collected from Steilacoom Lake, Pierce County, in Washington State, and amended with copper sulfate (nominal concentrations of 800, 1,000, 1,500, and 2,000 mg Cu/kg dry weight) to assess copper bioavailability to Hyalella azteca, Chironomus tentans, or Ceriodaphnia dubia. H. azteca survival and C. tentans survival and growth were not significantly affected, with 10-day no observed effects concentrations (NOEC) and lowest observed effects concentrations (LOEC) of 2,010 and >2,010 mg Cu/kg, respectively. C. dubia was the most sensitive organism tested with 10-day NOEC and LOECs for survival and reproduction of 906 and 1,469 mg Cu/kg, respectively. Sediment AVS concentrations were <0.15 μmol/g, while simultaneously extracted metal (SEM) concentrations were ≥5.71 μmol Cu/g. Dissolved interstitial water concentrations ranged from below detection (0.010 mg/L) to 0.24 mg Cu/L, with interstitial water toxicity units as high as 3.4. Based on this study, effects to C. dubia may occur at bulk sediment concentrations >906 mg Cu/kg. Further, AVS and interstitial water concentrations are not accurate predictors of copper bioavailability in Steilacoom Lake.
Copper Speciation and Microbial Activity in Long-Term Contaminated Soils by A. Dumestre; S. Sauvé; M. McBride; P. Baveye; J. Berthelin (pp. 124-131).
Most soil quality guidelines do not distinguish among the various forms of metals in soils; insoluble, nonreactive, and nonbioavailable forms are deemed as hazardous as highly soluble, reactive, and toxic forms. The objective of this study was to better understand the long-term effects of copper on microorganisms in relation to its chemical speciation in the soil environment. Carbon mineralization processes and the global structure of different microbial communities (fungi, eubacteria, actinomycetes) are still affected after more than 50 years of copper contamination in 20 soils sampled from two different agricultural sites. The microbial respiration lag period (LP) preceding the beginning of mineralization process increases with the level of soil copper contamination and is not significantly affected by other environmental factors such as soil pH and soil organic matter (SOM) content. The total copper concentration showed the best correlation with the LP when each site is considered separately. However, when considering the whole set of data, soil solution free Cu2+ activity (pCu2+) is the best predictor of Cu toxicity determined by LP (quite likely because pCu2+ integrates the soil physicochemical variability). The maximum mineralization rate (MMR), even if well correlated with the pCu2+, appears not to be a good biomonitor of copper contamination in soils since it is highly sensitive to soil characteristics such as SOM content. This study emphasizes the importance of the physicochemical properties of the environment on soil heavy metal toxicity and on soil toxicological measurements. These properties must be characterized in soil toxicological studies with respect to (1) their interactions with heavy metals, and (2) their direct impact on the selected biological test. The measurement of pCu2+ to characterize the level of soil contamination and of lag period as a bioindicator of metal effects in the soil are recognized as useful tools for the evaluation of the biological quality of soils.
Chlorinated Hydrocarbons in Coastal Lagoons of the Pacific Coast of Nicaragua by F. P. Carvalho; S. Montenegro-Guillen; J.-P. Villeneuve; C. Cattini; J. Bartocci; M. Lacayo; A. Cruz (pp. 132-139).
A screening for persistent chlorinated hydrocarbons was carried out in December 1995 in the main coastal lagoons on the Pacific side of Nicaragua, where most of the country's agriculture and pesticide use has been taking place for decades. Results for a wide range of organochlorine pesticides in lagoon sediments show levels that generally were very low in Estero Real, Estero Padre Ramos, and estuary of San Juan del Sur. For example, total DDTs in these lagoons averaged 4.5 ± 3.4 ng g−1 dry weight, which may be considered a baseline level for the region. Other compounds such as HCHs, BHC, endosulfan, heptachlor, endrin, toxaphene, and aroclors were present in concentrations even lower, generally below 1 ng g−1 dry weight. However, sediments of the Esteros Naranjo–Paso Caballos system at Chinandega district contained pesticide residues in much higher levels, attaining maximum values of 1,420 ng g−1 and 270 ng g−1 dry weight, respectively, for toxaphene and total DDTs. Other compounds such as aroclors, chlordane, endosulfan, and dieldrin were also present in the sediments of this lagoon system, but in lower concentrations. The very high concentrations of toxaphene and DDTs in this lagoon are a result of the intensive use of these pesticides in cotton growing in the district of Chinandega. Due to the long environmental half-lives of these compounds (t½ > 10 years in temperate soils), their concentrations in lagoon sediments will likely remain high for years to come. Based on these results, the development of the new shrimp farming activities in the Pacific coastal lagoons should be restricted to selected areas.
Contaminant Assimilation Within the Water Column of Two Newly Created Prairie Wetlands by A. P. Polonsky; W. H. Clements (pp. 140-145).
This research examined the influence of abiotic factors on contaminant assimilation within the water column of two wetlands (RMA3 and RMA4) located on Rocky Mountain Arsenal National Wildlife Area, north of Denver, Colorado, USA. We define contaminant assimilation as the ability of a wetland system to reduce negative impacts of contaminants on aquatic organisms. To examine the influence of abiotic factors (i.e., alkalinity, suspended solids), chronic toxicity tests were performed from February 1992 through November 1993. Ceriodaphnia dubia were exposed to water from the wetlands, which was spiked with Zn. These tests indicated higher assimilative capacity in wetland RMA4 relative to RMA3. Dissolved organic carbon (DOC) was significantly greater in RMA4 than in RMA3, suggesting that it may have influenced differences in bioavailability of Zn in wetland water. Suspended solids were also consistently higher in RMA4 than in RMA3. To test the influence of suspended solids on contaminant assimilation, C. dubia were exposed to filtered and unfiltered Zn-spiked water from RMA4. The greater toxicity of Zn to C. dubia in filtered water indicated that suspended solids were important in ameliorating impacts of Zn in RMA4. Results from this study suggest that from the suite of variables assessed, DOC and suspended solids were the most important physiochemical influences on Zn toxicity within the water column of these two wetlands. Differences in habitat characteristics of RMA3 and RMA4 demonstrated the importance of site-selection toward functional design of wetlands.
Biodegradation and Ecotoxicity of HFCs and HCFCs by A. G. Berends; C. G. de Rooij; S. Shin-ya; R. S. Thompson (pp. 146-151).
Hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) are used or developed as substitutes for fully halogenated chlorofluorocarbons. Based on the results of closed-bottle tests, the biodegradation of HFC-32, HCFC-123, HCFC-124, HFC-125, HFC-134a, HCFC-141b, HCFC-225ca, and HCFC-225cb was less than 60% after 28 days and therefore these compounds are considered not readily biodegradable. Standard acute toxicity tests with HCFC-123, HCFC-141b, and HCFC-225ca using algae, water fleas, and fish revealed EC50 values in the range of 17–126 mg/L. EC50 values of HFC-134a ranged between 450–980 mg/L. Fish studies with HCFC-141b and HCFC-225ca revealed bioaccumulation factors of <3 and 15–64, respectively. A study with plants revealed no effect of HCFC-141b on seed germination and growth of wheat (Triticum aestivum), radish (Raphanus sativus), and cress (Lepidium sativum). In conclusion, HFCs and HCFCs are not very toxic to aquatic organisms and terrestrial plants. No evidence for any aerobic biodegradation for most of the HFCs and HCFCs was found.
Soil-Based Phytotoxicity of 2,4,6-Trinitrotoluene (TNT) to Terrestrial Higher Plants by P. Gong; B.-M. Wilke; S. Fleischmann (pp. 152-157).
Seed germination and early stage seedling growth tests were conducted to determine the ecotoxicological threshold of 2,4,6-trinitrotoluene (TNT) in two soils of different properties. Soils were amended up to 1,600 mg TNT kg−1 soil and four representative species of higher plants, two dicotyledons (Lepidium sativum L., common name: cress; and Brassica rapa Metzg., turnip) and two monocotyledons (Acena sativa L., oat; and Triticum aestivum L., wheat), were assessed. Cumulative seed germination and fresh shoot biomass were measured as evaluation endpoints. Phytotoxicity of TNT was observed to be affected by soil properties and varied between plant species. Cress and turnip showed higher sensitivity to TNT than did oat and wheat. The lowest observable adverse effect concentration (LOAEC) of TNT derived from this study was 50 mg kg−1 soil. In contrast to high TNT concentrations, low levels of TNT, i.e., 5–25 mg kg−1 soil for cress and turnip and 25–50 mg kg−1 for oat and wheat, stimulated seedling growth. Oat was capable of tolerating as much as 1,600 mg TNT kg−1 and demonstrated a potential ability of TNT detoxification in one of the soils tested, suggesting that this plant might be useful in the bioremediation of TNT contaminated soils.
Structure of Peroxisomes and Activity of the Marker Enzyme Catalase in Digestive Epithelial Cells in Relation to PAH Content of Mussels from Two Basque Estuaries (Bay of Biscay): Seasonal and Site-Specific Variations by A. Orbea; I. Marigómez; C. Fernández; J. V. Tarazona; I. Cancio; M. P. Cajaraville (pp. 158-166).
The aim of the present work was to study the seasonal as well as the site-specific variations in the structure of peroxisomes and in the activity of the peroxisomal marker enzyme catalase in digestive epithelial cells of mussels to validate the potential use of these parameters as early biomarkers of environmental organic pollution in estuarine ecosystems. For this purpose, mussels were sampled monthly for 14 months in two Basque estuaries (Bay of Biscay) with different degrees of pollution. Stereological procedures were applied to detect changes in peroxisome structure, and microspectrophotometry was used to quantify changes in catalase activity. The animals from the two studied sampling sites presented differences in polycyclic aromatic hydrocarbon (PAH) burdens, mussels from Plentzia generally showing lower total PAH contents than mussels from Galea. The peroxisome structure of the animals from the two estuaries suffered seasonal variations that were of different kind and intensity in both sites. In this way, a strong peroxisome proliferatory response was found in mussels sampled in Plentzia during the summer months, while mussels from Galea presented few variations along the year. Catalase activity behaved similarly in the animals sampled in the two estuaries, with higher values in spring. It appeared that mussels exposed chronically to PAHs and other pollutants, such as those from Galea, lost their ability to respond to this exposure in terms of peroxisome proliferation. In contrast, mussels collected in Plentzia effectively responded to an increased bioavailability of organic pollutants during the summer by increasing peroxisome volume and surface and numerical densities in digestive epithelial cells. However, these increases were transient because elevated PAH body burdens detected in mussels sampled in Plentzia in autumn were not accompanied by a peroxisome proliferatory response. Further studies are needed before changes in peroxisomal structure and in the activity of catalase could be used as early biomarkers to assess environmental quality in pollution monitoring programs like the Mussel Watch.
Acute Toxicity, Toxicokinetics, and Tissue Target of Lead and Uranium in the Clam Corbicula fluminea and the Worm Eisenia fetida: Comparison with the Fish Brachydanio rerio by F. Labrot; J. F. Narbonne; P. Ville; M. Saint Denis; D. Ribera (pp. 167-178).
The general objective of our work was to propose new reference material for chemical toxicity testing and new sentinel organisms for environmental quality survey programs (freshwater or soils). We also wanted to provide basic toxicological data on the environmental effects of uranium. Thus, we conducted a comparative study to establish the acute toxicity and toxicokinetics of lead (Pb) and uranium (U) to the bivalve mollusc Corbicula fluminea and the terrestrial annelid Eisenia fetida andrei and to compare these findings with those of the well-known teleost fish Brachydanio rerio. We then measured the concentration of these metals in various tissues of the clam and the worm after two periods of exposure (4 and 11 days) to identify the affinities of these tissues for Pb and U. Our results have shown that Pb and U are very toxic to Eisenia and relatively nontoxic to Corbicula. By comparison, Pb was relatively nontoxic and U appeared to be very toxic to the fish. The toxicokinetic studies indicated that the three species are able to accumulate Pb and U, the rate and level of accumulation depending both on the species and the metal. We also found that fish and clams depurate the two metals. Data collected for the worm were conflicting: Pb was not depurated whereas tissue concentrations of U declined after the eighth day of exposure. Our study has also shown that the tissue distribution of Pb in the mollusc and in the earthworm differs significantly from that of U, both after 4 and 11 days exposure. In conclusion, these three species showed potential as bioindicators of environmental contamination by metals. Indeed, they could be used in conjunction to test different compartments of an ecosystem: worms for soils, fish for the water column, and clams for the water/sediment interface.
Divergent Kinetics of hsp70 Induction in Oniscus asellus (Isopoda) in Response to Four Environmentally Relevant Organic Chemicals (B[a]P, PCB52, γ-HCH, PCP): Suitability and Limits of a Biomarker by H.-R. Köhler; C. Knödler; M. Zanger (pp. 179-185).
Mature specimens of the isopod Oniscus asellus were maintained on soil and leaf litter to which was added different concentrations of either benzo[a]pyren (B[a]P), 2,2′,5,5′-tetrachlorobiphenyl (PCB52), γ-hexachlorocyclohexane (γ-HCH), or pentachlorophenol (PCP) for a maximum of 14 days. Time-dependent investigation of the body level of the 70 kD stress protein group (hsp70) in the isopods revealed a significant but transient induction of the hsp70 response after about 24 h of exposure to PCB52 or B[a]P. Despite continuous exposure, the hsp70 level decreased subsequently and ended up close to or below the control level independent of the concentration of PCB52 or B[a]P in the substrate. All applied PCP or γ-HCH concentrations also resulted in an initial peak of hsp70 response after 24 h of exposure and a second peak after several days of exposure, as well as an elevated hsp70 level throughout the period of exposure. Although acute stress conditions posed by all four organic chemicals were monitored by stress protein induction, hsp70 can act as a biomarker of chronic exposure and effect for PCP and γ-HCH only.
Caddisflies (Trichoptera: Hydropsychidae) Used for Evaluating Water Quality of Large European Rivers by S. C. Stuijfzand; S. Engels; E. van Ammelrooy; M. Jonker (pp. 186-192).
In many European rivers, biodiversity has declined dramatically, and especially riverine insects have disappeared during the past decades. It remains unclear whether poor water quality or deteriorated habitats are limiting the distribution of sensitive aquatic insects in these rivers. The aim of this study, therefore, was to find out if water quality alone is limiting the distribution of these insects in rivers that have suffered from anthropogenic disturbances. To this purpose, caddisflies of the genus Hydropsyche, which are representative riverine insect species, were incubated in two large European rivers, the Rhine and the Meuse. Survival of caddisflies in the River Rhine was fairly high, while there was almost no survival in the River Meuse in three out of five field experiments. The incubations of Hydropsyche in the River Meuse provide evidence that even adequate structural habitat would be insufficient for the reestablishment of Hydropsyche species. The factors limiting the distribution of Hydropsyche species change with the changing constitution of the water; there is not one (group of) compound(s) responsible for the poor water quality. Besides chemical factors, physical factors (like oxygen and current velocity) may be limiting in the River Meuse for Hydropsyche species.
The Toxicity of Glyphosate and Several Glyphosate Formulations to Four Species of Southwestern Australian Frogs by R. M. Mann; J. R. Bidwell (pp. 193-199).
The acute toxicity of technical-grade glyphosate acid, glyphosate isopropylamine, and three glyphosate formulations was determined for adults of one species and tadpoles of four species of southwestern Australian frogs in 48-h static/renewal tests. The 48-h LC50 values for Roundup® Herbicide (MON 2139) tested against tadpoles of Crinia insignifera, Heleioporus eyrei, Limnodynastes dorsalis, and Litoria moorei ranged between 8.1 and 32.2 mg/L (2.9 and 11.6 mg/L glyphosate acid equivalent [AE]), while the 48-h LC50 values for Roundup® Herbicide tested against adult and newly metamorphosed C. insignifera ranged from 137–144 mg/L (49.4–51.8 mg/L AE). Touchdown® Herbicide (4 LC-E) tested against tadpoles of C. insignifera, H. eyrei, L. dorsalis, and L. moorei was slightly less toxic than Roundup® with 48-h LC50 values ranging between 27.3 and 48.7 mg/L (9.0 and 16.1 mg/L AE). Roundup® Biactive (MON 77920) was practically nontoxic to tadpoles of the same four species producing 48-h LC50 values of 911 mg/L (328 mg/L AE) for L. moorei and >1,000 mg/L (>360mg/L AE) for C. insignifera, H. eyrei, and L. dorsalis. Glyphosate isopropylamine was practically nontoxic, producing no mortality among tadpoles of any of the four species over 48 h, at concentrations between 503 and 684 mg/L (343 and 466 mg/L AE). The toxicity of technical-grade glyphosate acid (48-h LC50, 81.2–121 mg/L) is likely to be due to acid intolerance. Slight differences in species sensitivity were evident, with L. moorei tadpoles showing greater sensitivity than tadpoles of the other four species. Adult and newly emergent metamorphs were less sensitive than tadpoles.
Comparative Effects of Ammonium and Nitrate Compounds on Pacific Treefrog and African Clawed Frog Embryos by G. S. Schuytema; A. V. Nebeker (pp. 200-206).
The effects of ammonium nitrate, ammonium chloride, ammonium sulfate, and sodium nitrate on survival and growth of Pacific treefrog (Pseudacris regilla) and African clawed frog (Xenopus laevis) embryos were determined in static-renewal tests. The 10-day LC50s for the three ammonium compounds for P. regilla ranged from 25.0–32.4 mg/L NH4 -N. The 10-day sodium nitrate LC50 for P. regilla was 578.0 mg/L NO3-N. LC50s for X. laevis exposed for 4 or 5 days to the three ammonium compounds ranged from 27.5–60.2 mg/L NH4-N. The sodium nitrate LC50 for X. laevis ranged from 438.4–871.6 mg/L NO3-N. The lowest LOAEL based on length or weight was 6.1 mg/L NH4-N for the two species. The lowest LOAELs for NO3-N were 111.1 mg/L for P. regilla and 56.7 mg/L for X. laevis. Calculated unionized NH3 comprised 0.5–1.8% of measured NH4-N concentrations. Potential harm to amphibian populations could occur if NH4-N and NO3-N in agricultural runoff or drainage impacts sensitive life stages for a sufficiently long period.
A Field Test of the Quotient Method for Predicting Risk to Microtus canicaudus in Grasslands by G. Wang; W. Edge; J. O. Wolff (pp. 207-212).
We used gray-tailed voles, Microtus canicaudus, as an experimental model species to field test a prediction of the Quotient Method (QM) for risk to small mammals of an insecticide in grasslands. In May 1997, we placed voles into 12 0.2-ha enclosures planted with a mixture of pasture grasses. In late July, we applied 1.55 kg/ha of the insecticide Guthion® 2S (azinphos-methyl) in three treatments: a control (all habitat sprayed with water), full spray (all of the habitat sprayed with Guthion 2S), and half-spray (one-half of the habitat sprayed with Guthion 2S and one half with water). Five replicates were used for the half-spray and control, and two replicates for the full-spray. The Guthion 2S treatment did not depress population size, growth rate, or survival of voles in half-spray or full-spray enclosures. Our results were inconsistent with the QM prediction for use of Guthion 2S in grass habitats. These results also differed from our previous studies in alfalfa habitats in which measurable responses were detected at the same application rate. The differences probably are due to the different types of vegetation between current and previous studies. The grass habitat in our enclosures was an average of 60 cm high and was very thick from ground level to about 40 cm. Much of the residue likely accumulated in the upper strata of vegetation and did not reach ground level at this application rate. Under the conditions of this study, voles were less affected in grassland habitat than they were in alfalfa habitat.
Short-Term Distribution, Metabolism, and Excretion of 2,2′,5-Tri-, 2,2′,4,4′-Tetra-, and 3,3′,4,4′-Tetrachlorobiphenyls in Prepubertal Rats by S. A. Saghir; G. D. Koritz; L. G. Hansen (pp. 213-220).
The excretion and tissue retention of three 14C-labeled lower chlorinated biphenyls were examined in prepubertal male and female Sprague-Dawley rats following IV administration. Urine and feces were collected individually at different time intervals up to 72 h for pharmacokinetic analyses. After 72 h, different organs were removed and extracted in acetone:hexane (1:1, v/v) to determine radioactivity. Within the first 10 h after dosing, 2,2′,5-trichlorobiphenyl (PCB 18) was rapidly excreted in urine (8–18% of the administered dose), whereas only 0.6–0.8% of 2,2′,4,4′-tetrachlorobiphenyl (PCB 47) and 0.3–0.8% 3,3′,4,4′-tetrachlorobiphenyl (PCB 77) were found in urine during this time period. The half-life of elimination was shortest for PCB 18 (37.5 to 49.2 h). The half-lives for PCB 47 and PCB 77 were 351 to 672 h and 152 to 186 h, respectively. The cumulative total excretion (urinary + fecal) of PCB 18 within 72 h was 51–62%, of PCB 77 was 22–25%, and of PCB 47 was 7–10%. No parent PCBs were detected in urine. PCB 47 accumulated preferentially in adipose tissues (subcutaneous fat > mesenteric fat); relatively high levels of PCB 47 were also found in adrenals, ovaries, lungs, liver, and skin. The highest concentration of PCB 77 was found in serum, followed by adipose tissues. Very low concentrations of PCB 18 were found in most tissues; the highest being found in serum, followed by ovaries and adrenal glands. This study suggests that prepubertal rats retain higher short-term serum levels and have lower excretion rates than adult rats.
Reproductive Performance of Two Generations of Female Semidomesticated Mink Fed Diets Containing Organic Mercury Contaminated Freshwater Fish by M. Dansereau; N. Larivière; D. Du Tremblay; D. Bélanger (pp. 221-226).
Semidomesticated female mink (Mustela vison) were fed daily diets containing 0.1 ppm, 0.5 ppm, and 1.0 ppm of total mercury. Piscivorous and nonpiscivorous fish naturally contaminated with organic mercury were used to prepare the diets. Twenty-month-old females (G1 generation) that were exposed to the experimental diets for approximately 400 days in 1994 and 1995 and their 10-month-old female offspring (G2 generation) that were exposed to mercury for approximately 300 days in 1995, were all mated to 10-month-old males. Males were fed the diet containing 0.1 ppm mercury 60 days prior to the mating season. Diets containing 0.1 ppm and 0.5 ppm were not lethal to G1 and G2 females for an exposure period of up to 704 days. At the age of 11 months, mortalities occurred in 1994 for G1 females (30/50) and in 1995 for G2 females (6/7) fed the 1.0 ppm mercury diet after 90 days and 330 days of exposure, respectively. The length of the gestation periods and the number of kits born per female were not different among dietary groups for the two generations of females. The proportion of females giving birth was low for all groups, except for the G1 females fed the 0.1 ppm diet. There was an inverse relationship between whelping proportion and exposure group, but was not statistically significant. There was evidence that kits were exposed to mercury both in utero and/or during lactation as indicated by the presence of mercury in their livers. Mercury exposure did not influence the survival and growth of neonatal kits.
Determination of Dietary Tin Intake in an Adult French Citizen by G. H. Biégo; M. Joyeux; P. Hartemann; G. Debry (pp. 227-232).
The tin contents in fresh food or in food stored in lacquered or unlacquered cans were determined in order to estimate the daily tin intake in a French citizen. Tin levels were 76.6 ± 36.5 mg/kg in foods preserved in unlacquered cans, 3.2 ± 2.3 mg/kg in foods stored in lacquered cans, and 0.03 ± 0.03 mg/kg in fresh foods. Tin intake is essentially dependent on food stored in tin cans (98%), which only represents 5.6% of the total daily consumption of foods by a French citizen. The estimated tin intake (2.7 mg/day whether 0.04 mg/kg of body weight) remains widely inferior to the daily tolerable dose in humans (2 mg/kg of body weight).