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Archives of Environmental Contamination and Toxicology (v.35, #1)
Rapid SPME/LC/MS/MS Analysis of N-Methylcarbamate Pesticides in Water by D. A. Volmer; J. P. M. Hui (pp. 1-7).
Solid-phase microextraction combined with fast short-column liquid chromatography/electrospray ionization tandem mass spectrometry (SPME/LC/MS/MS) was used for isolating and analyzing nine N-methylcarbamate pesticides from water samples. Several SPME parameters, such as polarity of fibers, extraction time, and effect of ionic strength, were investigated and their impact on the SPME/LC/MS/MS technique was studied. The method was shown to be sensitive with detection limits between 0.3 and 1.9 μg/L and reproducible with precision between 4.5 and 12.7% RSD. The versatility of the method was exhibited by its excellent linearity in the concentration range of 2–2,000 μg/L in drinking water. A comparison of the SPME/LC/MS/MS method with LC/MS/MS methods utilizing traditional sample preparation techniques shows that the former offers similar performance in terms of precision and linearity, but is clearly easier to use and faster to perform.
The Influence of Extraction Procedure on Ion Concentrations in Sediment Pore Water by P. V. Winger; P. J. Lasier; B. P. Jackson (pp. 8-13).
Sediment pore water has the potential to yield important information on sediment quality, but the influence of isolation procedures on the chemistry and toxicity are not completely known and consensus on methods used for the isolation from sediment has not been reached. To provide additional insight into the influence of collection procedures on pore water chemistry, anion (filtered only) and cation concentrations were measured in filtered and unfiltered pore water isolated from four sediments using three different procedures: dialysis, centrifugation, and vacuum. Peepers were constructed using 24-cell culture plates and cellulose membranes and vacuum extractors consisted of fused-glass air stones attached with airline tubing to 60-cc syringes. Centrifugation was accomplished at two speeds (2,500 and 10,000 g) for 30 min in a refrigerated centrifuge maintained at 4°C. Only minor differences in chemical characteristics and cation and anion concentrations were found among the different collecting methods with differences being sediment-specific. Filtering of the pore water did not appreciably reduce major cation concentrations, but trace metals (Cu and Pb) were markedly reduced. Although the extraction methods evaluated produced pore waters of similar chemistries, the vacuum extractor provided the following advantages over the other methods: ease of extraction, volumes of pore water isolated, minimal preparation time, and least time required for extraction of pore water from multiple samples at one time.
Effects of Soil Copper on Black Bindweed (Fallopia convolvulus) in the Laboratory and in the Field by C. Kjær; M. B. Pedersen; N. Elmegaard (pp. 14-19).
The present study aims to identify factors of importance to the extrapolation from laboratory toxicity test to field effects using copper and black bindweed as a model. In the laboratory the influence of Cu on seed germination and seedling survival was studied in both soil spiked with Cu in the laboratory and soil collected at a Cu-polluted site. Maternal effects were also studied. We found that seeds from Cu-stressed plants germinated more readily after a short, cold storage than control seeds, but no differences were found after a longer storage. The low germination of control seeds compared to maternal treated seeds could not be attributed to differences in thickness of the seed coat. Germination was slightly stimulated at 232 mg Cu kg−1. At the highest Cu level (i.e. 1,330 mg Cu kg−1) only 5% of the seeds germinated. Mortality of the seedlings increased with increasing Cu concentration reaching 40% at 391 mg Cu kg−1. At higher concentrations mortality decreased. Germination was not affected in laboratory tests with soil from a Cu-polluted site, but the biomass of the plants decreased with increasing Cu concentration. The distribution of the plants on a Cu-polluted site was registered in relation to soil Cu concentration. Cu was analyzed using three different extractors, i.e. HNO3, CaCl2, and DTPA. The distribution of the plant in the field was predicted from calculated lifetime effect of a given Cu soil concentration based on the laboratory tests. The results revealed that growth is more sensitive in the field than should be expected from laboratory tests due to several stressors in the former situation. Bioavailability was lower in the field soil but this was counteracted by the increased effect. Incorporating bioavailability in the prediction of field effects thus reduced the fit of the model and bioavailability measures could not be further evaluated.
A Laboratory Assay to Assess Avoidance of Contaminated Sediments by the Freshwater Oligochaete Lumbriculus variegatus by C. W. West; G. T. Ankley (pp. 20-24).
Responses of benthic organisms to contaminated sediments in the laboratory historically have been assessed as survival, growth, and reproduction. However, these responses do not include behavioral aspects of organisms, which also can influence species distribution and abundance in benthic communities. This study documents avoidance behavior of the freshwater oligochaete Lumbriculus variegatus to contaminated sediments in the laboratory, utilizing a chamber specifically built to facilitate the measurement of this response. A number of field-collected sediments from sites with known contamination, several of which exhibited little or no toxicity in standard tests examining growth and/or survival, were evaluated. The oligochaetes exhibited marked avoidance to many of the sediments, indicating the potential utility of this assay in identifying effects of contaminated sediments on benthic community structure.
Effects of Copper and Zinc on Embryos and Larvae of the Horseshoe Crab, Limulus polyphemus by M. L. Botton; K. Johnson; L. Helleby (pp. 25-32).
We investigated the short-term and long-term effects of copper and zinc on horseshoe crab (Limulus polyphemus) embryos and first instar larvae from two estuaries in New Jersey, Delaware Bay and Sandy Hook Bay. Animals were exposed to nominal metal concentrations from 0.01 to 1,000 mg/L for 24 h, 48 h, 72 h, or continuously until the endpoint for the study (successful molting or death) was reached. Larvae showed greater tolerance of Cu and Zn than embryos. Under most treatment regimes, embryos and larvae were able to survive and molt in the presence of up to 100 mg/L Cu or Zn. Unexpectedly, horseshoe crabs from the more heavily polluted site (Sandy Hook Bay) were more susceptible to heavy metals than animals from a less polluted site (lower Delaware Bay). Horseshoe crab embryos and larvae were highly resistant to heavy metals in comparison to marine crustacea. The ability of Limulus embryos and larvae to survive in the presence of heavy metals implies the potential for these contaminants to be passed on to shorebirds and other predators.
Developmental Abnormalities in Horseshoe Crab Embryos Caused by Exposure to Heavy Metals by T. Itow; R. E. Loveland; M. L. Botton (pp. 33-40).
We examined the effects of heavy metals on the development of horseshoe crabs using bioassays in which embryos at different stages were exposed either continuously or for 24 h. Abnormalities included segment-defective embryos, double embryos, embryos with abnormal eye areas, and no-posterior embryos. In terms of their ability to affect normal development, the pollutants are ranked as follows: Hg ≥ organotin > Cr (equals with falling dots) Cd > Cu > Pb > Zn. Organotin treatment was associated with a high frequency of abnormal eye embryos and Hg with segment-defective embryos. The specific cause of segment-defective malformations by Hg was investigated by using SH inhibitors and cytochalasin B, an inhibitor of microfilaments. These inhibitors induced Hg-type segment-defective embryos; thus, Hg may also act by inhibiting SH-SS exchange and blocking morphogenetic movements. Horseshoe crab embryos from Delaware Bay and Sandy Hook Bay, New Jersey, were examined for developmental abnormalities. Malformed embryos were extremely rare (<0.6%) at five beaches along Delaware Bay as well as Sandy Hook Bay, suggesting that these horseshoe crab spawning areas are relatively unpolluted by heavy metals.
Accumulation of Tributyl- and Triphenyltin Compounds in Pacific Oyster, Crassostrea gigas, from the Chinhae Bay System, Korea by W. J. Shim; J. R. Oh; S. H. Kahng; J. H. Shim; S. H. Lee (pp. 41-47).
Butyl- and phenyltin residues were quantified in seawater and Pacific oyster (Crassostrea gigas) from the Chinhae Bay System, Korea. Butyltin compounds were detected in all the seawater and C. gigas samples, whereas phenyltin compounds were not detected in any seawater samples. Tributyltin (TBT) concentrations in seawater ranged <8–35 ng Sn L−1. TBT and triphenyltin (TPhT) concentrations in oysters ranged 95–885 and 155–678 ng Sn g−1, respectively. Spatial distribution of TBT was closely related to boating and dry-docking activities. However, spatial distribution of TPhT was not consistent with that of TBT. The estimated biological concentration factor (BCF) for TBT in C. gigas was about 25,000. Furthermore, 19 and 28% of total body burdens of TBT and TPhT were found in gonadal mass of C. gigas just prior to the spawning period, indicating that a proportional amount of TBT and TPhT would be released with a following reproductive process.
Impact of Guthion on Survival and Growth of the Frog Pseudacris regilla and the Salamanders Ambystoma gracile and Ambystoma maculatum by A. V. Nebeker; G. S. Schuytema; W. L. Griffis; A. Cataldo (pp. 48-51).
The effects of the insecticides Guthion (technical grade) and Guthion 2S (commercial formulation) on survival and growth of tadpoles of the Pacific treefrog Pseudacris regilla, and larvae of the Northwestern salamander Ambystoma gracile and the spotted salamander Ambystoma maculatum were determined in continuous-flow exposures in the laboratory. Ninety-six–hour LC50 values were >3.6 mg/L for P. regilla with technical grade Guthion and 1.47 mg/L with the formulation Guthion 2S (measured as active ingredient Guthion). Ten-day LOAEL and NOAEL values based on length and weight for P. regilla with Guthion were 3.60 and 0.98 mg/L. LOAEL and NOAEL values based on length and weight for P. regilla with Guthion 2S were 0.17 and 0.07 mg/L. The 96-h LC50 for Guthion 2S was 1.67 and 1.90 mg/L for A. gracile and A. maculatum, respectively. LOAEL and NOAEL values based on length and weight for A. gracile with Guthion 2S were 0.22 and 0.10 mg/L; they were 0.11 and 0.03 mg/L for A. maculatum based on weight. These species are as similar in sensitivity as some fish species but are more tolerant to Guthion than most invertebrates.
The Impact on Reproduction of an Orally Administered Mixture of Selected PCBs in Zebrafish (Danio rerio) by S. Örn; P. L. Andersson; L. Förlin; M. Tysklind; L. Norrgren (pp. 52-57).
Zebrafish (Danio rerio) were orally exposed to a mixture of 20 PCBs in three different dose levels (0.008, 0.08, and 0.4 μg of each congener per gram of freeze-dried chironomids). Generally, the PCBs accumulated in a dose-related manner. After 13 weeks of exposure body, liver, and ovary weights, as well as the liver and ovary somatic index, were significantly lower in exposed groups. In addition, the PCB mixture was an effective inducer of hepatic EROD activity. The reproduction study performed with exposed females and unexposed males after 9 weeks revealed that median survival time for larvae was only 7.7 days in the high-dose group as compared with 14 days in controls. Furthermore, egg production was reduced in all three groups exposed. No differences in hatching frequency or median hatching time were recorded. Histologically, females in both the intermediate and high-dose groups contained a reduced number of mature oocytes. The present study demonstrates that the potency of the mixture of selected PCBs induces hepatic EROD activity and has a clearly negative effect on zebrafish reproduction.
Biochemical Composition, Growth, and Survival of the Guppy, Poecilia reticulata, During Chronic Sublethal Exposure to Cadmium by H. Miliou; N. Zaboukas; M. Moraitou-Apostolopoulou (pp. 58-63).
The survival, growth, and biochemical composition (protein, total lipid, total carbohydrate, free reducing sugars, RNA, DNA) of the guppy, Poecilia reticulata, exposed to low sublethal concentrations of cadmium throughout its life cycle (beginning with 5-day-old juveniles) was studied. The purpose was to get some insight on the cause of metal toxic effects and evaluate the utility of monitoring levels of biomolecules as bioindicators of chronic toxicant effects on fish. The LC50 (48 h) of cadmium for 5-day-old Poecilia was 56.77 mg/L. The median lethal times (LT50) of Poecilia exposed to low cadmium concentrations (0.5–5 mg/L) ranged from 7.65 to 72.51 days, and could be accurately predicted by the mortality observed after 20 days of exposure. The whole-body dry weight increase of cadmium-exposed guppies presented a decline from that of the controls. These declines were statistically significant after 20 days of exposure to concentrations higher than 1 mg/L and after 30 days to concentrations higher than 0.5 mg/L. The percentage content in RNA was the only variable from the studied macrobiomolecules that significantly decreased when guppies were exposed to Cd concentrations higher than 0.5 mg/L for 30 days. The same trend was apparent in the ratio RNA/DNA. However, the ratio protein/RNA/DNA significantly increased after 10 days of growth to 1.5 mg/L and after 20 days to concentrations higher than 0.5 mg/L, thus having a predictive value for early-life history stages of Poecilia exposed to Cd.
Occurrence of Butyltin Compounds in Tissues of Water Birds and Seaducks from the United States and Canada by K. Kannan; K. Senthilkumar; J. E. Elliott; L. A. Feyk; J. P. Giesy (pp. 64-69).
Tributyltin and its breakdown products, mono- and di-butyltin, were determined in water birds collected from Lake Huron (the Great Lakes), marine coastal United States, and the west coast of British Columbia, Canada. Concentrations of butyltins in the liver of birds collected from Lake Huron were ≤ 27 ng/g, wet wt, whereas those from marine coastal areas contained up to 90 ng/g. Relatively higher concentrations were found in seaducks collected from coastal British Columbia, with concentrations as great as 1,100 ng/g. Mollusk-feeding seaducks seemed to accumulate greater concentrations of butyltins than predatory birds feeding on fish, other birds and small mammals. Hepatic concentration ranges of butyltins in birds from the United States and Canada were compared with those reported for the UK, Netherlands, Japan, and Poland. Exposure of birds to butyltin compounds continues to occur in harbors and marinas where TBT is used on vessels greater than 25 m in length.
Lead Concentration in the Bones of the Feral Pigeons (Columba livia): Sources of Variation Relating to Body Condition and Death by M. Janiga; M. Zemberyová (pp. 70-74).
This paper reports on lead concentrations in the tarsometatarsi of 84 individuals of adult feral pigeons Columba livia found dead or experimentally captured in Bratislava, Slovakia. The interrelationships between lead concentrations and time of death, place of death, body measurements, sex, condition, and plumage phenotype were investigated. Size and shape of pigeons was not correlated with bone lead contamination. Sex and plumage color and pattern were slightly associated with variation in bone lead levels, females and melanic (urban) phenotypes tending to have higher bone lead concentrations than males and blue-bar (wild) individuals. Birds with antibodies to chlamydiae did not contain significantly higher lead concentrations in the tarsometatarsi than birds without antibodies. Concentration of lead in tarsi was significantly higher in birds dying in winter, compared to birds dying at the end of summer. Chronic lead poisoning probably causes mortality in pigeons in winter. The natural stressor, cold weather, has the capability of exacerbating the effects of lead poisoning, and the mortality is due to lead exposure coupled with cold stress.
Elemental Profiles in Feather Samples from a Mercury-Contaminated Lake in Central California by T. M. Cahill; D. W. Anderson; R. A. Elbert; B. P. Perley; D. R. Johnson (pp. 75-81).
Flight feathers from six bird species at Clear Lake, CA were analyzed to determine the extent and distribution of mercury contamination from an abandoned mercury mine and associated levels of 14 other elements. Feather samples were collected from adult and juvenile osprey (Pandion haliaetus), including juvenile osprey from three additional comparison sites; adult western grebes (Aechmophorus occidentalis); adult great blue herons (Ardea herodias); adult mallards (Anas platyrhynchos); adult turkey vultures (Cathartes aura); and juvenile double-crested cormorants (Phalacrocorax auritus). Samples were analyzed by a multielemental x-ray fluorescence method. The osprey from Clear Lake showed significantly elevated mercury concentrations relative to the comparison sites. Different species at Clear Lake had different mercury concentrations based on trophic status; osprey exhibited the highest mercury concentrations and the mallards showed the lowest. Lastly, we quantified differences in elemental concentrations, including mercury, between adult and juvenile osprey from Clear Lake. Elements known to be nutrients, such as sulfur and zinc, did not vary significantly among species or sites. Reproductive success of osprey at Clear Lake was monitored from 1992 to 1996 to determine if osprey reproduction was depressed. During this five-year period, the breeding population grew from 10 to 20 nesting pairs and the average reproductive rate was 1.4 fledglings per nesting attempt. Although the osprey showed the highest mercury levels of any species sampled, their reproduction does not appear to be depressed.
Aluminum and Acid Effects on Calcium and Phosphorus Metabolism in Young Growing Chickens (Gallus gallus domesticus) and Mallard Ducks (Anas platyrhynchos) by M. C. Capdevielle; L. E. Hart; J. Goff; C. G. Scanes (pp. 82-88).
Acidification is associated with increased mortality, reduced growth, and bone abnormalities in birds. Associated with acid deposition is an increase in aluminum availability due to solubilization from soil and other sources. (Conversely, experimental diets containing aluminum sulfate have much reduced pHs.) The present studies compare the effects of two levels of dietary acid (sulfuric acid) (0.122 and 0.56 mol H+ per kg feed; 0.056 and 0.277 mol sulfate per kg feed) and dietary aluminum (aluminum sulfate at 0.1 and 0.5%; sulfate at 0.056 and 0.277 mol sulfate per kg feed) on bone growth, mineralization, and phosphorous/calcium homeostasis in growing birds (chickens and mallard ducks). Growth was reduced by the high acid (chicken) and aluminum (ducks and chickens) diets. A reduction in bone mineralization was observed in birds receiving aluminum-containing diets [low aluminum diet: decreased tibia ash, calcium, and phosphorus (chickens); high aluminum diet: decreased tibia dry weight, % of ash and mg; ash, calcium (chickens, ducks as % of ash), and phosphorus (chickens mg/duck, % of ash)]. Moreover, plasma concentrations of inorganic phosphate were reduced in chicks on the high aluminum diet. There were also marked decreases in bone growth and mineralization [tibia weight, ash (mg), calcium (mg), phosphorus (mg)] and plasma concentrations of 1,25-dihydroxy vitamin D3 in chicks on the high acid diet compared to those on a control diet. These changes were probably due to reduced feed intake; changes in bone indices being of a greater or similar magnitude in pairfed control. There was little change in bone indices, growth rate or feed consumption in ducklings receiving either the low or high acid diets. It is concluded that aluminum directly adversely affected bone mineralization whereas acid effects are mediated in part by changes in feed consumption.
Metabolism and Cytotoxicity of Chlorpropham (CIPC) and Its Essential Metabolites in Isolated Rat Hepatocytes During a Partial Inhibition of Sulphation and Glucuronidation Reactions: A Comparative Study by G. Carrera; J. Alary; M. J. Melgar; Y. Lamboeuf; B. Pipy (pp. 89-96).
The changes in metabolism and cytotoxicity of chlorpropham (CIPC) and its major metabolites, 4-hydroxychlorpropham (4-OH CIPC), 3-chloroaniline, and 3-chloroacetanilide were investigated in isolated rat hepatocyte suspensions after a partial inhibition of sulphation and glucuronidation and the two reactions combined in an attempt to assess the part of each of them in the enhanced CIPC toxicity observed in vivo after D-galactosamine treatment. With sulphation and glucuronidation effective, CIPC has a cytolytic effect and reduces intracellular ATP and K+ level while 4-OH CIPC has a weak cytolytic effect but modifies ATP and K+ level in a greater extent than CIPC. Inhibition of sulphation does not affect the cytotoxicity of CIPC or 4-OH CIPC because there is a compensatory increase in the amount of 4-OH CIPC glucuronide formed and the level of free 4-OH CIPC always remain low. In contrast, when incubations are carried out with either CIPC or 4-OH CIPC, the presence of D-galactosamine leads to a decrease of glucuronide and sulphate conjugates accompanied, respectively, by a 3.6-fold and 6.9-fold increase of the free 4-OH CIPC level in the culture medium. This alteration of the metabolism is followed by a marked reduction of ATP synthesis with a concomitant modification of cell permeability. The cytolytic effect is due to CIPC itself, whereas the effect on energy supply was attributed to free 4-OH CIPC. The results demonstrate a combined effect of free 4-OH CIPC and D-galactosamine on intracellular ATP level that could account for the partial inhibition of sulphation. This change in the CIPC metabolism could explain the increased CIPC toxicity observed in vivo after D-galactosamine pretreatment.
Hepatic Enzyme Induction and Acute Endocrine Effects of 2,3,3′,4′,6-Pentachlorobiphenyl in Prepubertal Female Rats by M.-H. Li; C. Rhine; L. G. Hansen (pp. 97-103).
Polychlorinated biphenyls (PCBs) with the labile 2,3,6-substitution are important components of atmospheric and certain food chain exposures, but little is known about their biological activities. Chlorobiphenyl 110 (2,3,3′,4′,6-pentaCB) was investigated in weanling female rats dosed ip on days 21 and 22 and killed on day 23 of age. The initial preparation of CB 110 markedly induced 7-ethoxyresorufin O-dealkylase (EROD) activity and was found to be contaminated with coplanar 3,3′,4,4′,5-pentaCB (CB 126). The contaminated preparation (CB 110C) was purified with activated charcoal (CB 110P). The CB 110P induced pentoxyresorufin O-dealkylase (PROD), was weakly uterotropic and a modest depleter of serum thyroxine (T4). CB 110C caused increased liver weight, induced EROD, PROD, and UDP glucuronyl transferase activities and caused a greater depletion of serum T4; on the other hand, it suppressed the PROD induction and the uterotropic effect of CB 110P. Hepatic residues of CB 110 were a constant 2-3% of the dose while those of CB 126 (from CB 110C) increased with increasing dose to as much as 50% of the dose.
Metabolic Conversion of 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) to 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) in the Male F344/NCr Rat by S. D. Fox; J. M. Roman; H. J. Issaq; R. W. Nims (pp. 104-108).
1,1-Dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) levels were measured by capillary gas chromatography with electron capture detection in liver and blood serum of male F344/NCr rats exposed for 2 weeks to DDD at dietary concentrations ranging from 8.51 ppm to 2,000 ppm. DDD burdens in serum ranged from <0.006 μM (limit of detection) in control rats to 1.1 μM in the rats fed DDD at 2,000 ppm. The corresponding liver burdens in these animals ranged from <0.006 μmol/kg liver (controls) to 11 μmol/kg liver in rats fed DDD at 2,000 ppm. Levels of DDE in serum or liver were undetectable (<0.006 μM in serum; <0.006 μmol/kg liver) in rats fed control diet or diet containing 8.51 or 25.5 ppm DDD. The liver and serum burdens of DDE increased with dietary DDD concentration, reaching a maximum of 0.53 μM in serum and 4.7 μmol/kg liver in rats fed 2,000 ppm DDD. As a percentage of total DDD equivalents detected in liver or serum, the DDE burdens increased to a maximum of 36% and 31% in the serum and liver, respectively, of rats fed 689 ppm DDD. The possibility that the DDE might have been generated artifactually in the diet prior to administration to the rats was ruled out by analysis with capillary gas chromatography of the diet containing 2,000 ppm DDD. The identification of DDE as a metabolite in liver extracts of rats fed 2,000 ppm DDD was confirmed with GC-MS. The results confirmed the presence of DDE as a metabolite of DDD.
Radiation Exposure and Dose to Small Mammals in Radon-Rich Soils by C. R. Macdonald; M. J. Laverock (pp. 109-120).
Protection of the environment from radionuclide releases requires knowledge of the normal background levels of radiation exposure in the exposed biotic community and an estimate of the detriment caused by additional exposure. This study modeled the background exposure and dose to the lungs of small burrowing mammals from 222Rn in artificial burrows in radon-rich soils at a site in southeastern Manitoba. E-PERM chambers used to measure 222Rn in soil showed good reproducibility of measurement, with an average coefficient of variance (CV) of about 10%. Geometric mean (GM) 222Rn concentrations at nine randomly selected sites ranged from 5,490 Bq/m3 (GSD = 1.57, n = 7) to 41,000 Bq/m3 (GSD = 1.02, n = 5). Long-term monitoring of 222Rn concentrations in artificial burrows showed large variation within and between burrows and did not show consistent variation with season, orientation of the burrow opening, or levels of 226Ra in the soil. Annual GM concentrations in individual burrows ranged from 7,480 Bq/m3 (GSD = 1.60) to 18,930 Bq/m3 (GSD = 1.81) in burrows several meters apart. A grand GM of 9,990 Bq/m3 (GSD = 1.81, n = 214) was measured over the site for the year. An exposure model was constructed for five small mammal species based on their respiration rates and the number of hours spent in the burrow, active or hibernating, exposed to soil gas 222Rn, and the time spent out of the burrow exposed to atmospheric 222Rn. A background dose of 0.9 mGy/a from atmospheric 222Rn (40 Bq/m3) was estimated for a large-bodied (80 kg), nonburrowing animal living on the soil surface. The highest exposures (mJ/a) in burrowing mammals occurred in those species with the highest respiration rates. Hibernation accounted for a small fraction of total annual exposure (<5%) because of very low respiration rates during this period. Absorbed dose to lung (mGy/a) was highest in the pocket gopher and decreased in the larger animals because of larger lung mass. Using mean 222Rn concentrations from the field studies and an equilibrium factor (F) of 0.5, doses to lung ranged from 90 mGy/a in the badger to 700 mGy/a in the pocket gopher. These doses closely correspond to those estimated from published dose conversion factors (DCFs) of 1.4 mGy per mJ · h/m3 for whole lung. For the ground squirrel, the DCF approach gives an estimated dose of 300 mGy/a versus 270 using the respiratory flow rate method. Based on these results, doses exceeding 500 mGy/a may be common in mammals and birds (i.e. the burrowing owl) living in radon-rich soils. Published risk coefficients for small mammals suggest that about 17 cancers would occur in 1,000 animals at these exposure rates. Although the potential effects from these exposures were not examined in this study, the study raises questions about how the animals may respond physiologically to this largely natural stress.
Methyl Sulphone Metabolites of Polychlorinated Biphenyls (PCBs) in Cetaceans from the Irish and the Aegean Seas by G. M. Troisi; K. Haraguchi; M. P. Simmonds; C. F. Mason (pp. 121-128).
The levels of PCBs and PCB methyl sulphone metabolites were determined in the blubber of six species of cetaceans that originated from the Irish Sea and the Aegean Sea (Mediterranean). Burdens ranging from 2.80 to 27.80 μg g−1 (lipid weight) total PCBs and 0.03 to 0.58 μg g−1 (lipid weight) total methyl sulphones were recorded. The highest cetacean methyl sulphone burden (0.58 μg g−1) was in an Irish Sea harbor porpoise (Phocoena phocoena). Methyl sulphone isomer formation capacity, as determined by PCB:MSF ratios, varied considerably between species as follows: harbour porpoise (1:10) > pilot whale (Globicephalus melas), white-sided dolphin (Lagenorhyncus acutus) (1:50) > common dolphin (Delphinus delphis), Risso's dolphin (Grampus griseus), and striped dolphin (Stenella coerueoalba), (1:100), and was related to interspecific variation in PCB methyl sulphone formation capacity.
Reduction in Human Exposure to Pesticide Using Traditional Work Clothing Fabrics with Chemical Finishing: Carboxymethylation and Starch by E. Csiszár; J. Borsa; I. Rácz; S. K. Obendorf (pp. 129-134).
Franz diffusion experiments with human skin combined with work-clothing fabric have shown that skin exposure to pesticides is reduced by the presence of traditional nonbarrier textiles. This study was undertaken to obtain further information about the reduction in exposure using traditional work-clothing fabrics that had chemical finishing to increase the sorption properties. The effects of a renewable starch finish and chemical modification by carboxymethylation on cotton fabrics on the pesticide (methyl parathion) retention, transfer, and decontamination by laundering were investigated. Two weights of work clothing fabrics made of 100% cotton were used, one appropriate for shirts and the other for pants. The amount of pesticide observed on human skin was reduced by the presence of clothing fabric. Carboxymethylation of the shirt fabric reduced the amount of pesticide observed on the human skin. This treatment also resulted in less pesticide being transferred to a second fabric layer within a clothing system. No pesticide penetrated to the second fabric layer when the heavier pant fabric was used as the outer layer. The lighter weight shirt fabric did not retain as much pesticide as the pant fabric. The pesticide retained on the shirt fabric was increased by the application of a renewable starch finish and by carboxymethylation; both of these finishes were found to be effective in enhancing the decontamination of cotton fabrics by laundering.
Determinants of Polychlorinated Biphenyl Levels in Plasma from 42-Month-Old Children by C. I. Lanting; V. Fidler; M. Huisman; E. R. Boersma (pp. 135-139).
We report on the PCB levels in plasma from 42-month-old children and the factors that determine these levels. We measured the levels of the PCB congeners 118 (2,4,5-3′4′ pentachlorobiphenyl (CB)), 138 (2,3,4-2′4′5′hexaCB), 153 (2,4,5-2′4′5′hexaCB), and 180 (2,3,4,5-2′4′5′heptaCB) in cord plasma, breast milk, and plasma from 42-month-old children (n = 126) living in the Groningen area, The Netherlands. The sum of the levels of these four congeners was calculated for cord plasma (ΣPCBcord), breast milk (ΣPCBmilk), and 42-month plasma (ΣPCB42mo). ΣPCBcord was used as a measure of prenatal exposure. Postnatal exposure was assessed in terms of the ΣPCBmilk and the duration of lactation. In addition, maternal factors including age, body weight and height, parity, and formal education were recorded. In 42-month-old children who have been fully breast-fed for at least six weeks as babies, the median ΣPCB42mo was 4.5 times as high as that in formula-fed children (0.81 μg/L vs. 0.18 μg/L). The PCB levels in cord blood and human milk and the duration of breast-feeding predict the plasma PCB level at 42 months. Each additional week of full breast-feeding is estimated to result in an increase of 0.3% of the milk PCB level. We concluded that lactation is a major source for the child's PCB body burden at 42 months.
Chlororganic Pesticides and Polychlorinated Biphenyls in Breast Tissue of Women with Benign and Malignant Breast Disease by S. Güttes; K. Failing; K. Neumann; J. Kleinstein; S. Georgii; H. Brunn (pp. 140-147).
Persistent chlorinated hydrocarbons assimilated through the diet may, as a result of their carcinogenic, immunotoxic, and, at least in regard to certain of these substances, estrogenic properties, play a role in the etiology of human breast cancer. As a consequence, increased concentrations of these ubiquitous environmental contaminants may be found in breast tissue of women suffering from malignant breast disease. To examine this possibility, surgically removed breast tissue samples from 65 women in Hesse, Germany were examined by capillary gas chromatography for p,p′-dichloro(diphenyl)trichloroethane (p,p′-DDT), p,p′-dichloro(diphenyl)-dichloroethane (p,p′-DDD), p,p′-dichloro(diphenyl)dichloroethene (p,p′-DDE), hexachlorobenzine (HCB), α-, β-, and γ-hexachlorocyclohexane (HCH) as well as the polychlorinated biphenyls (PCB) no. 28, 31, 49, 52, 101, 105, 118, 138, 153, 156, 170, and 180. Of the 65 patients, 45 were diagnosed with breast cancer. The control group of 20 women suffered from benign breast disease such as mastopathy. After statistical adjustment for age differences, higher concentrations of p,p′-DDT, p,p′-DDE, HCB as well as PCB-congeners no. 118, 138, 153, and 180 were detected in tissue from women with breast cancer than in tissue from control persons. These differences were weakly significant for p,p′-DDE (p = 0.017), for PCB 118 (p = 0.042) and for PCB no. 153 barely not significant (p = 0.083). On an average, a 62% higher concentration of p,p′-DDE was found in cancer tissue (cancer patients: 805 μg/kg fat; controls: 496 μg/kg fat) and 25% higher concentration of PCB no. 118 (81 μg/kg fat; 65 μg/kg fat). The concentrations of β-HCH, PCB no. 156 and 170 were lower (not significant) in cancer tissue than in tissue from women with benign disease. PCB-congeners no. 105 and 149 as well as γ-HCH could only be detected in individual tissue samples; congeners no. 28, 31, 49, 52, and 101 as well as α-HCH and p,p′-DDD were not detected in any of the samples. To rule out the possibility that the concentrations of chlorinated hydrocarbons measured were influenced by the surgical procedure, 20 samples of tissue that were at a distance (minimum 1 cm and maximum 3 cm) from the tumor, tissue that was in direct proximity to the tumor (no more than 5 mm from the tumor), and tumor tissue itself (center of tumor) were separately prepared and analyzed. The average concentrations of chlorinated hydrocarbons varied to differing degrees and only minimally in tumor and surrounding breast tissue, indicating that the surgical procedure did not influence the results.
Colon Cancer Mortality and Total Hardness Levels in Taiwan's Drinking Water by C.-Y. Yang; C.-F. Hung (pp. 148-151).
The possible association between the risk of colon cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible colon cancer deaths (1,714 cases) of Taiwan residents from 1989 through 1993 were compared with deaths from other causes (1,714 controls) and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan have been collected from Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair matched to the cases by sex, year of birth, and year of death. The results show a significant negative relationship between drinking water hardness and colon cancer mortality. Odds ratio and 95% confidence intervals were 1.22 (1.04–1.43) and 1.46 (1.22–1.75), respectively, for exposure to moderately hard water and soft water compared with the use of hard water. Trend analyses showed an increasing odds ratio for colon cancer with decreasing levels of hardness in drinking water. This is an important finding for the Taiwan water industry and human health.
Atherosclerotic Risks from Chemicals: Part I. Toxicological Observations and Mechanisms of Atherosclerosis by S. R. Basavaraju; T. D. Jones (pp. 152-164).
Atherosclerosis is a common disease, primarily of the large arteries, that begins in childhood and progresses with advancing age. Atherosclerosis leads to coronary heart disease, the major cause of death in the United States. Several risk factors affect atherosclerosis, but high LDL cholesterol is the most important risk factor. In addition, high levels of lipoprotein (a) appear to be associated with increased atherosclerosis and myocardial infarction. The level of lipoprotein (a) is genetically determined and is not affected by diet or exercise. Studies on the pathogenesis of atherosclerosis suggest that several steps are involved, including endothelial injury, increased arterial permeability to plasma lipoproteins, smooth muscle cell proliferation, and platelet aggregation. Atherosclerotic plaques are benign neoplasms of the arterial wall that result from the monoclonal proliferation of a single mutated smooth muscle cell. Abnormal proliferation of smooth muscle cells is the key event in the initiation and progression of atherosclerosis. Endothelial injury is another major contributory factor. Many factors associated with an increased risk of cancer are also associated with atherosclerosis. Cancer and atherosclerosis go through the same stages of initiation, promotion, and complication. Both inflammatory and immune reactions play important roles in the progressions of the two diseases. Smooth muscle cells and endothelial cells produce and respond to several cytokines and growth factors, which may influence the initiation, progression, and complication of the atherosclerotic lesions. Many studies have shown that the production of nitric oxide is decreased in atherosclerosis—reduction in the bioavailability of nitric oxide in the arterial wall may lead to leukocyte adhesion and platelet aggregation. It should be noted additionally, nitric oxide is a mutagenic agent involved in the origin of neoplastic diseases. Atherosclerotic plaques express genes for products not found in the normal arterial wall. As with carcinogenesis, there may be more than one mechanism that promotes atherosclerotic lesions and there may be common mechanistic similarities between the two diseases. The purpose of this study is to establish an exploratory scientific hypothesis that will permit the use of standardized toxicological test data to evaluate different chemicals. The companion paper that follows will use a method of relative toxicological potencies to develop tentative risk coefficients based on relative potency. These papers, in combination, provide both a conceptual and a quantitative hypothesis that can be tested with data from forthcoming epidemiological studies or animal test models.
Atherosclerotic Risks from Chemicals: Part II. A RASH Analysis of In Vitro and In Vivo Bioassay Data to Evaluate 45 Potentially Hazardous Compounds by T. D. Jones; M. D. Morris; S. R. Basavaraju (pp. 165-177).
As reviewed in the Part I companion manuscript by Basavaraju and Jones (Arch Environ Contam Toxicol), atherosclerosis and carcinogenesis may share some common mechanisms of toxicological action. On that hypothesis, standardized test data taken from the Registry of Toxic Effects of Chemical Substances (RTECS) were used to compute relative potency factors for chemical compounds associated with increased risk of atherosclerosis to humans. Potencies of the different compounds were computed relative to each of six reference compounds comprised of benzo(a)pyrene, nicotine, cisplatin, adriamycin, estrogen, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. Reference-specific potencies were all converted to a common numerical scale adjusted to unit potency for B(a)P. Because the list of compounds contained several antibiotics, amino acids, hormones, chemotherapeutic agents, polynuclear aromatics, alkaloids, metals, and vitamins, the standardized estimates of potency varied significantly depending on which of the six reference compounds are considered as standards of comparison. For the n − 1 other substances. Estimates of relative potency, risk coefficients, and generalized risk equations are estimated for cigarette smoke condensate, dietary cholesterol, ethanol, and carbon disulfide. From data on atherosclerosis as a result of cigarette smoking, a tentative risk was estimated as Increased Relative Risk = S (mg/kg-day)−1× dose (mg/kg-day) × RP, where the dose is chronic intake per kilogram of body weight per day, RP is the potency of the compound of interest relative to that of benzo(a)pyrene, and S is 0.83, 0.25, 0.20, or 13 depending on whether cigarette smoke, cholesterol, ethanol, or carbon disulfide epidemiological data were used as a standard of comparison.