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Archives of Environmental Contamination and Toxicology (v.40, #3)
Transformation Pathways of 14C-Chlorothalonil in Tropical Soils by J. B. Regitano; V. L. Tornisielo; A. Lavorenti; R. S. Pacovsky (pp. 295-302).
Chlorothalonil (CTN) is a chlorinated wide-spectrum fungicide, heavily and widely applied throughout the world. This study was undertaken to directly evaluate the rates and forms of 14C-labeled CTN dissipation in three acid Brazilian soils (Typic Humaquept [GH], Typic Quartzipsamment [AQ], and Typic Hapludox [LE]). Mineralization was not the major metabolic pathway of CTN-degrading microorganisms. However, CTN dissipation was fast in all soils and was mainly due to biodegradation (responsible for 50%, 54%, and 73% of 14C-CTN dissipation in the GH, LE, and AQ soils, respectively), as well as to formation of soil-bound 14C residues (responsible for 46%, 34%, and 18% of 14C-CTN dissipation in the GH, LE, and AQ soils, respectively). Most soil-bound 14C residues were formed in the first day, but aging also contributed to the formation of less reversible forms of CTN-soil complexes. In these acid soils, the most abundant metabolite formed from CTN degradation was 3-carbamyl-2,4,5-trichlorobenzoic acid.A significant fraction of the CTN that had been assumed to be rapidly degradable in soils in previous reports has turned out to be soil-bound residues. Although bioavailability of any compound is reduced when soil complexes are formed, further research is needed to evaluate accumulation and availability of CTN soil-bound residues over long-term applications, and the consequent detrimental effects on the environment and on soil quality and fertility.
The Evaluation of Metal Retention by a Constructed Wetland Using the Pulmonate Gastropod Helisoma trivolvis (Say) by R. R. Goulet; E. N. Leclair; F. R. Pick (pp. 303-310).
Constructed wetlands are built because they can act as sinks for many pollutants, thereby protecting the water quality of downstream ecosystems. The treatment performance is generally assessed using mass balance calculations. Along with the mass balance approach, we compared the metal content of populations of a common pond snail (Helisoma trivolvis Say) collected upstream and downstream of a 3-year-old constructed wetland. Snails were collected in early May, June, and August 1998. At the same time, water samples for particulate and dissolved metals were taken every 3 days for the duration of the experiment. Overall, the wetland retained most dissolved metals, including Fe, Mn, Cu, Zn, Ni, and Pb, but released dissolved As. However, the wetland released particulate Fe and Mn. With the exception of Zn, the metal concentrations of the downstream snails were on average higher than those measured in the upstream population. The higher metal content of downstream snails was likely related to the significant export of particulate metals by the wetland, despite the overall retention of dissolved metals. This study points to the need for biological as well as chemical monitoring to determine the treatment efficiency and toxicological risk associated with constructed wetlands.
Immunotoxicity of Explosives-Contaminated Soil Before and After Bioremediation by L. A. Beltz; D. R. Neira; C. A. Axtell; S. Iverson; W. Deaton; T. J. Waldschmidt; J. A. Bumpus; C. G. Johnston (pp. 311-317).
Soils from the Yorktown Naval Base contaminated with trinitrotoluene (TNT) and other explosives were used to prepare eluates before and after bioremediation using microbial growth amendments in the presence (P1 eluates) or absence (P2 eluates) of exogenous white rot fungus. Effectiveness of bioremediation was examined by several immunotoxicity assays—viability/growth of lymphocytes, cytokine production, and expression of the interleukin-2 (IL-2) receptor—using human peripheral blood mononuclear cells exposed to the eluates. Although TNT concentrations decreased in both P1 and P2 eluates relative to untreated baseline soil (BL) eluates, a recovery in lymphocyte growth/viability and IL-2 secretion was seen with P2 but not P1 eluates relative to BL eluates. IL-2 receptor levels were higher in cells exposed to BL and P2 eluates than when exposed to P1 eluates. Interferon-γ, tumor necrosis factor-β, and IL-10 levels were highest in BL and P2 eluates and lowest in P1 eluates. Taken together, these results suggest that treatment of the soil with microbial growth amendments in the absence but not the presence of exogenous white rot fungi lead to partial bioremediation as assessed by lymphocyte functions.
Toxicity of Freshwater Sediments in the Vicinity of an Old Sawmill: Application of Three Bioassays by M. Lyytikäinen; A. Sormunen; T. Ristola; R. Juvonen; J. V. K. Kukkonen (pp. 318-326).
Toxicity of contaminated sediments collected from an old sawmill area and the downstream river-lake system was assessed with three different bioassays. Survival and growth were used as endpoints in subchronic (10-day) test with Chironomus riparius and growth and reproduction in long-term (28-day) test with Lumbriculus variegatus. A microbial bioluminescent direct contact assay, the Flash test, was also included in the test set to measure acute toxicity. In every bioassay, sediment from a pool of the sawmill was found to be toxic, and some adverse effects were found in other sediments as well. The bioassays were then compared to chemical analysis results, which showed the presence of several toxicants. These results could not, however, be directly connected to any individual toxicant, nor did they show any obvious trend downstream from the mill.
Influence of Aqueous Sediment Extracts from the Oder River (Germany/Poland) on Survival of Diplostomum sp. (Trematoda: Diplostomidae) Cercariae by M. Pietrock; T. Meinelt; D. J. Marcogliese; C. E. W. Steinberg (pp. 327-332).
Laboratory experiments were carried out to test whether the life span of Diplostomum sp. cercariae is affected by contamination of its aquatic environment. Freshly emerged cercariae therefore were exposed to either standardized water, Oder River (Germany/Poland) or Lake Odersee (Germany) extracts of aqueous sediments; mortality patterns and mean survival times (MSTs) were compared. Cercariae added to extracts of aqueous sediments from the Oder River and Lake Odersee exhibited impaired survival with significantly different mortality pattern and reduced MST compared to that of controls. A significant negative correlation (r =−0.843, p < 0.05) was found between MST and mercury content of sediments, indicating a potential impact of mercury on survival of Diplostomum sp. cercariae. The results indicate that contamination of freshwater habitats may influence the viability of free-living transmission stages of helminth parasites of fish and may thus be of epizootiological significance.
Effects of Dissolved Organic Material on Binding and Toxicokinetics of Pyrene in the Waterflea Daphnia magna by A. Nikkilä; J. V. K. Kukkonen (pp. 333-338).
The binding and bioavailability of pyrene was studied in the laboratory in two humic fresh waters and in a reference water without dissolved organic material (DOM), measured as dissolved organic carbon (DOC). The uptake of pyrene by Daphnia magna in short-term (24 h) accumulation experiments was fitted to a first-order rate-kinetic equation to calculate simultaneous uptake and elimination rates. The partition coefficients of pyrene to DOC (KDOC) were 37.1 × 103 in Pielisjoki River (9.4 mg DOC L−1), and 34.9 × 103 in Lake Kontiolampi (17.4 mg DOC L−1) waters, indicating similar binding affinities of pyrene for both humic waters. The uptake clearance of pyrene (ku) in the DOC-rich Lake Kontiolampi water was 290.4 ml g wet weight−1 h−1, which was lower than those in Pielisjoki River and DOC-free waters (395.8 and 346.0 ml g wet weight−1 h−1, respectively). Pyrene elimination (ke) was in average 0.2 h−1 with no significant differences between the waters. The observed bioconcentration factors of pyrene in Pielisjoki River and Lake Kontiolampi waters were 84% and 46% of that in the DOC-free reference water, respectively, thus indicating that a high concentration of DOC is needed to decrease the bioavailability of waterborne pyrene to D. magna.
Accumulation of 109Cd by Second-Generation Chironominae Propagated from Wild Populations Sampled from Low-, Mid-, and High-Saline Environments by L. Barjaktarovic; L. I. Bendell-Young (pp. 339-344).
Our objective was to determine if second-generation (F2) chironomids propagated from adults of larvae sampled from low-, mid-, and high-saline environments differed in their ability to accumulate cadmium from their environment. Second-generation chironomids cultured from wild populations were exposed to 109Cd at 0, 0.7, and 4.3 ppt salinity for 10 days, at which time survival and amounts of 109Cd accumulated were determined. Cultures included two of Chironomus tentans from a freshwater lake (lake 78; 0 ppt), and the euryhaline C. athalassicus from a mid- (lake 71; 0.7 ppt) and high (lake 56; 4.3 ppt)-saline environment. A laboratory-reared culture of C. tentans was included as a positive control. Species-dependent accumulation of 109Cd occurred; second-generation C. athalassicus cultured from the high-salinity lake survived in the three salinities and accumulated significantly greater amounts of the radiotracer at 0 and 0.7 ppt compared to the second-generation freshwater species, C. tentans. Second-generation C. athalassicus cultured from lake 71 also survived all salinities with 109Cd accumulation tending to be greater than the freshwater species at the mid-salinity range. In contrast, the freshwater species cultured from lake 78 as well as the laboratory-reared culture did not survive the highest salinity of 4.3 ppt and accumulated less 109Cd compared to the species from the high-saline environments. Species-dependent differences in metal accumulation need to be considered in studies that assess metal concentrations in aquatic organisms across an environmental gradient, such as salinity.
Toxicity and Bioaccumulation of Arsenic and Chromium in Epigean and Hypogean Freshwater Macroinvertebrates by V. Canivet; P. Chambon; J. Gibert (pp. 345-354).
Lethal toxicity levels of two inorganic water pollutants, chromium (Cr6+) and arsenic (As3+), were determined toward six freshwater macroinvertebrate species collected from a single field site. Crustaceans were represented by two amphipod species, an epigean one (Gammarus fossarum) and a hypogean one (Niphargus rhenorhodanensis), and by an isopod species (Asellus aquaticus). There were two insect larvae, Heptagenia sulphurea (Ephemeroptera) and Hydropsiche pellucidula (Trichoptera) and a snail, Physa fontinalis. Median lethal concentrations (LC50s) were determined over 96-h and 240-h periods for chromium and over a 240-h period for arsenic. Arsenic bioaccumulation was studied, too. The macroinvertebrates tested showed a wide range of sensitivity and bioaccumulation. A comparison between 96-h and 240-h experiments demonstrated that there was an increase in toxicity values following a longer time exposure for chromium. Also chromium was more toxic toward crustaceans than arsenic; conversely, arsenic was more toxic for the insect larvae and snail tested here. The lethal concentrations determined for the two metals were discussed and compared to results from other toxicity studies. The use of such macroinvertebrates, collected in the field and tested for longer exposure periods than within the standardized 96-h tests, should provide more suitable results for monitoring the general environmental quality of freshwater systems.
Organochlorine Pesticides and PCBs in a Southern Atlantic Coastal Lagoon Watershed, Argentina by M. L. Menone; J. E. Aizpún de Moreno; V. J. Moreno; A. L. Lanfranchi; T. L. Metcalfe; C. D. Metcalfe (pp. 355-362).
There recently have been increasing interest in South America on organic pollutants from the coastal marine environment. This study intended to seek out the occurrence and distribution of persistent organochlorine compounds in the Mar Chiquita coastal lagoon watershed. The levels were measured in sediments and associated crabs. Though a significant number of PCBs (mainly penta- and hexachlorinated congeners) were detected, the concentrations were very low (in the order of ppbs), indicative of an estuarine environment with little industrial development. On the other hand, pesticide residues were higher than PCBs in one or two orders of magnitude, as a result of the important agricultural activities in the area. Heptachlor epoxide, DDT and its metabolites, and γ-HCH were the predominant OC pesticides in sediments as well as in crabs.Significant differences among geographical areas: Channel 5 and Vivoratá Creek (northern and southern sampling sites, respectively) contained detectable pesticide concentrations (heptachlor epoxide, DDE, DDD, and mirex).
Use of Japanese Medaka (Oryzias latipes) and Tilapia (Oreochromis mossambicus) in Toxicity Tests on Different Industrial Effluents in Taiwan by C.-M. Chen; S.-C. Yu; M.-C. Liu (pp. 363-370).
In Taiwan, aquatic toxicity tests for industrial effluents are not required for discharge permits. However, relying on traditional chemical and physical characteristics of an effluent to monitor and regulate such discharges to manage water quality of a receiving water is insufficient. In this study, we used two fish species, Japanese medaka (Oryzias latipes) and tilapia (Oreochromis mossambicus), and three toxic endpoints, including acute and subacute toxicity, to determine toxicity of seven different types of industrial effluents. Prior to the study, two reference toxicants were tested on two fish species. The LC50s of CdCl2 for tilapia and medaka juveniles were 29.6 ± 15.3 mg/L and 2.2 ± 1.2 mg/L, respectively. The sensitivity of medaka embryo mortality and hatching inhibition to CdCl2 were about the same, with the LC50 and EC50 of 0.3 ± 0.1 mg/L and 0.1 ± 0.1 mg/L, respectively. The LC50s for tilapia and medaka juveniles to sodium dodecyl sulfate (SDS) were 19.7 ± 10.6 mg/L and 12.5 ± 5.9 mg/L. The medaka embryo was less sensitive to SDS than to CdCl2. The embryo's LC50 for SDS was 5.8 ± 2.8 mg/L and the hatching inhibition EC50 was 1.3 ± 1.1 mg/L. Results of toxicity tests on different effluents showed that the electroplating effluent was the most toxic, followed by acrylonitrile manufacturing and pulp/paper mill discharges. The LC50s of the electroplating effluent to different assays were in the range of several percents of the whole effluent. The pulp/paper effluent was toxic only to the medaka embryo. The rest of the industrial effluents tested showed either moderate or no toxicity to the animals.
Effects of Dissolved Copper on Select Hematological, Biochemical, and Immunological Parameters of Wild Rainbow Trout (Oncorhynchus mykiss) by G. M. Dethloff; H. C. Bailey; K. J. Maier (pp. 371-380).
Rainbow trout (Oncorhynchus mykiss) were sampled from a creek in the western Sierra Nevada, Plumas County, CA, that receives run-off from a 40-ha copper (Cu) tailings pile. Reference sites included a site upstream of the Cu input and another site located on a nearby creek. Hepatic Cu concentrations were significantly elevated in trout from sites with elevated dissolved Cu concentrations compared with concentrations in trout from reference sites. Trout at the Cu-contaminated sites also exhibited decreased hematocrit (Hct), leukocrit (Lct), and percentage of lymphocytes in blood compared to trout from reference sites. The percentage of monocytes in blood and respiratory burst activity were affected by gender and age, respectively. Condition factor, percentage of neutrophils in blood, muscle glycogen and protein, and plasma acetylcholinesterase were not affected by dissolved Cu concentration or gender. Age also did not appear to be a factor. The data from this study support the use of immune system parameters to assess alterations in salmonids experiencing prolonged exposure to low-level Cu contamination and illustrate the variability in physiological responses of wild fish caused by demographic features. Overall, of the parameters measured, Hct, Lct, and percentage of lymphocytes in blood appeared to offer robust measures for assessing effects of metals on wild fish and did not appear affected by select demographic features.
Nonuniform Accumulation of Cadmium and Copper in Kidneys of Wild Brown Trout (Salmo trutta) Populations by J. D. Woodling; S. F. Brinkman; B. J. Horn (pp. 381-385).
Cadmium and copper accumulated nonuniformly in the kidney of wild brown trout on a longitudinal gradient as follows: the concentration in head kidney < anterior portion of tail kidney < posterior portion(s) of tail kidney. Zinc accumulated uniformly along the length of the kidney. Cadmium and copper accumulation in brown trout kidneys was lowest in the head kidney, where hematopoietic tissue dominates, and greatest in posterior tail sections, where filtration tissues dominate. Sampling programs designed to monitor cadmium and copper accumulation in trout kidneys should utilize the entire kidney, including the head kidney, to create comparable data sets.
The Effects of Tributyltin (TBT) and 3,3′,4,4′,5-Pentachlorobiphenyl (PCB-126) Mixtures on Antibody Responses and Phagocyte Oxidative Burst Activity in Channel Catfish, Ictalurus punctatus by R. P. Regala; C. D. Rice; T. E. Schwedler; I. R. Dorociak (pp. 386-391).
The organotin tributyltin (TBT) is an antifouling biocide used in marine paints and is a common pollutant in harbor estuaries. We previously demonstrated that the immune system of channel catfish, Ictalurus punctatus, is a sensitive target organ of TBT. Exposure strongly suppresses humoral immune responses. Harbor estuaries often contain polychlorinated biphenyls (PCBs) due to their ubuquitous distribution. The coplanar congener 3,3′,4,4′5′-polychlorinated biphenyl (PCB-126) is also immunotoxic to channel catfish, but it suppresses only the innate immune responses and only at high doses. In this study we exposed channel catfish to TBT, PCB-126, or both in mixtures, with canola oil (CO) serving as the carrier control. Antibody responses to Vibrio anguillarum and phagocyte oxidative burst activity were measured after (1) a single dose of 0.01 or 1 mg/kg of each or both in combination, and (2) six injections of 1.7 or 170 μg/kg of each (or in combination) given every 3 days over a 16-day period to yield a cumulative dose of 0.01 or 1 mg/kg, respectively. We measured antibody responses to V. anguillarum 21 days after immunization and oxidative burst activities 14 and 21 days after the final treatment. The highest dose of TBT suppressed antibody responses after a single exposure. The high dose of PCB-126 also suppressed antibody responses. The addition of PCB-126 to TBT doses did not alter the antibody responses beyond the effects of TBT alone. In the repeated exposure group, only the high dose of TBT suppressed antibody responses. In animals exposed to mixtures, high levels of PCB-126 enhanced suppression associated with low levels of TBT, whereas PCB-126 protected against suppression associated with high levels of TBT. Single exposures to TBT or PCB-126 suppressed phagocyte oxidative burst activity. In animals exposed to mixtures, as a single exposure, the addition of a low dose PCB-126 protected against low dose TBT-related oxidative burst activity suppression. In the repeated exposure groups TBT suppressed oxidative burst activity, but only at the highest dose on day 21, while high doses of PCB-126 suppressed activity on day 14. Furthermore, low levels of PCB-126 reversed the suppressed oxidative burst activity associated with high levels of TBT on day 21. Overall, this study demonstrates moderate additivity in terms of the immunotoxicity of TBT and PCB-126 mixtures using these two endpoints of immune function in the channel catfish model.
Altered Serum Sex Steroids and Vitellogenin Induction in Walleye (Stizostedion vitreum) Collected Near a Metropolitan Sewage Treatment Plant by L. C. Folmar; N. D. Denslow; K. Kroll; E. F. Orlando; J. Enblom; J. Marcino; C. Metcalfe; L. J. Guillette Jr. (pp. 392-398).
Several recent in situ studies have reported that domestic and mixed domestic/industrial sewage effluents contain one or more natural or anthropogenic estrogenic substances. Those studies examined caged or feral fish for the presence of the egg yolk precursor protein, vitellogenin (VTG), in the blood of male fish. We have previously reported that male, feral carp (Cyprinus carpio) obtained from the effluent channel of a major sewage treatment plant (STP) exhibited depressed serum testosterone (T) concentrations, as well as detectable levels of VTG. The present study examines male and female walleye (Stizostedion vitreum), a native species with a different life history and feeding habits, collected from the same Mississippi River locations below the St. Paul metropolitan STP. All male and female walleye collected from the effluent channel contained measurable levels of VTG in their blood. Males from that location also exhibited depressed serum T concentrations and elevated serum estradiol-17β (E2) concentrations compared with males from the Snake River reference site. Males obtained from Mississippi River Navigational Pool #2 (MRP-2), 3–20 miles downstream of the STP also exhibited reduced serum T concentrations, but showed no alterations in E2 concentrations or the presence of VTG in the serum. Females collected at the STP site had greatly elevated serum E2 concentrations, but serum T concentrations were not different from females collected in the Snake River. Our results demonstrate that the St. Paul metropolitan STP continues to release an estrogenic effluent, capable of inducing VTG production and altering normal serum sex steroid concentrations in a commercially valuable, native fish, the walleye. Additional studies will be required to determine whether these observations portend long-term population level effects.
Failed Recruitment of Southern Toads (Bufo terrestris) in a Trace Element-Contaminated Breeding Habitat: Direct and Indirect Effects That May Lead to a Local Population Sink by C. L. Rowe; W. A. Hopkins; V. R. Coffman (pp. 399-405).
We conducted a transplant study in which embryonic southern toads (Bufo terrestris) were held in a site polluted with coal ash (site AB; containing As, Cd, Cr, Cu, Se, and other elements) and a reference site (site R) through hatching and early larval development. To examine the remainder of the larval period, surviving larvae in AB were then transplanted to R and back-transplanted to AB, whereas surviving larvae from R were back-transplanted to R. Survival through early larval development was lower in AB than in R (34% versus 50%). However, site of hatching did not influence traits later in development (larval metabolic rate, larval morphology, duration of larval period, size at metamorphosis, or average hopping distance by metamorphs). Toads that spent the entire larval period in R had high rates of survival (70–94% of individuals transplanted after the embryonic period) regardless of where they spent the embryonic and early larval period. However, toads held in AB for the duration of the larval period suffered 100% mortality. Algal resources were scarce and their trace element concentrations high in AB compared to R, suggesting that mortality of larval toads resulted from a combination of direct toxicity (via sediment- and foodborne exposure) and indirect effects on resource abundance. The study suggests that the widespread practice of disposing of coal ash in open aquatic basins may result in sink habitats for some amphibian populations.
Sensitivity to Urea Fertilization in Three Amphibian Species by A. Marco; D. Cash; L. K. Belden; A. R. Blaustein (pp. 406-409).
Forest fertilization with granular urea is a well-established management practice in many forested regions of the world. We hypothesize that chemical forest fertilizers may be affecting forest-dwelling wildlife. In the laboratory, we studied the effects of fertilization doses of granular urea on three species of forest-dwelling amphibians (Plethodon vehiculum, Rhyacotriton variegatus, and Taricha granulosa). In avoidance experiments, the three species avoided a substrate treated with a dose of 225 kg N/ha urea. In toxicity experiments, we exposed amphibians to urea at doses of 225 kg N/ha and 450 kg N/ha for 4 days. The observed effects increased with time and dose, and there were significant differences in sensitivity among the species. Both treatment levels had an acute effect on survival of P. vehiculum and R. variegatus. At 24 h, mortality at the highest dose was 67% for P. vehiculum, and 47% for R. variegatus. In contrast, there was no mortality for T. granulosa at these concentrations. We suggest that environmental levels of urea could be affecting behavior and survival of some amphibians species in fertilized forests.
Organochlorine Pesticides, PCBs, Dibenzodioxin, and Furan Concentrations in Common Snapping Turtle Eggs (Chelydra serpentina serpentina) in Akwesasne, Mohawk Territory, Ontario, Canada by S. R. de Solla; C. A. Bishop; H. Lickers; K. Jock (pp. 410-417).
Subsamples of eight clutches of common snapping turtle eggs (Chelydra serpentina serpentina) were collected from four sites from the territory of the Mohawk Nation, Akwesasne, on the shore of the St. Lawrence River. Egg contents were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), dibenzodioxins, and furans. The sites were 2 to 13 km downstream from PCB-contaminated landfill sites. Maximum concentrations of total PCBs in snapping turtle clutches were extremely high, and ranged from 2 378.2 ng/g to 737 683 ng/g (wet weight) and are among the highest recorded in any tissue of a free-ranging animal. Similarly, in a pooled sample of eggs from all four sites, the summed concentrations of non-ortho PCBs (n = 6 congeners) was also very high at 54.54 ng/g and the summed dioxin and furan concentrations (n = 11 congeners) was 85.8 ng/g. Sum organochlorine pesticide levels varied from 28 to 2,264 ng/g among the four sites. The levels of PCBs found in turtle eggs exceed concentrations associated with developmental problems and reduced hatching success in snapping turtles and other species and also exceed the Canadian tissue residue guidelines for toxic equivalency concentrations. The extremely high levels of organochlorine contaminants demonstrate the high degree of contamination in the environment in the Akwesasne area.
Effects of Multiple Exposures of Small Doses of Pembina Cardium Crude Oil and Diesel in Rats by A. A. Khan; R. W. Coppock; M. M. Schuler (pp. 418-424).
In lands used for agricultural purposes, petroleum- or diesel-contaminated wastes and accidental spills of crude oil at some drilling sites pose exposure risks for occupational public, livestock, and wildlife. This study has assessed the effects of an Alberta crude oil, Pembina Cardium crude oil (PCCO), and a commercial diesel fuel #2 (CDF-2) in Sprague-Dawley rats after repeated exposures at small dose levels. Rats were given by gavage on day 1, 3, 5, and 8 specified dosages of either the control vehicle, methylcellulose (MC) (1.25 ml/kg), or PCCO (0.25–1.25 ml/kg), or CDF-2 (1.25 ml/kg). Exposure of rats to these dose levels of the test substances caused no overt symptoms of intoxication. A small but statistically significant increase in liver somatic index was observed in rats exposed to 1.25 ml/kg doses of PCCO and CDF-2; however, kidney somatic index was not significantly affected by these treatments. Blood analyses for hematological and clinical indicators of systemic impairments did not show any significant changes (p > 0.05) between the control and PCCO- or CDF-2-exposed rats. Biochemical assessment of liver and kidney tissues showed that compared to the control group, the PCCO- and CDF-2-exposed groups had a marked and significant increase (p < 0.05) in the hepatic activity of ethoxyresorufin-O-deethylase (EROD, a cytochrome P-450 [CYP] 1A1/A2–linked enzyme). In PCCO-exposed rats, the induction of EROD was dose-dependent. Exposure of rats with PCCO and CDF-2 also caused dose-related increases from the unexposed (control) or MC dosed rats in (1) hepatic activities of aryl hydrocarbon hydroxylase (AHH, a CYP 1A1–linked enzyme), ethoxycoumarin-O-deethylase (ECOD, a CYP 2B/1A–linked enzyme), glutathione transferase (GT), and NADPH-catalyzed microsomal lipid peroxidation; and (ii) ECOD activity in kidneys. The induction of hepatic CYP-linked enzymatic activities by PCCO and CDF-2 could be due to de novo synthesis of selected isoforms, as evidenced by the relative differences in the inhibition of EROD activity with 7,8-benzoflavone or metyrapone.
Cadmium in Organic and Conventional Pig Production by A. Lindén; K. Andersson; A. Oskarsson (pp. 425-431).
The main sources of cadmium (Cd) input to soils have been phosphate fertilizers and deposition from air. In organic farming, phosphate fertilizers are not used, which may in the long term result in lower Cd levels. In the present study, feed, kidney, liver, and manure from growing/finishing pigs raised conventionally and organically on the same farm were microwave-digested and analyzed for Cd by graphite furnace atomic absorption spectrometry. Cd was also analyzed in soil and water. A quality control program was included. The organic pigs (n = 40) were raised outdoors and fed an organic feed; the conventional pigs (n = 40) were raised indoors and given a conventional feed. The Cd levels in organic and conventional feed were 39.9 μg/kg and 51.8 μg/kg, respectively. Organic feed contained 2% potato protein, which contributed 17% of the Cd content. Conventional feed contained 5% beet fiber, which contributed 38% of total Cd content. Both feeds contained vitamin-mineral mixtures with high levels of Cd: 991 μg/kg in organic and 589 μg/kg in conventional feed. There was a significant negative linear relationship between Cd concentration in kidney and kidney weight. There was no significant difference in liver Cd levels between organic and conventional pigs and the mean ± SD was 15.4 ± 3.0. In spite of the lower level of Cd in the organic feed, the organic pigs had significantly higher levels in kidneys than the conventional pigs, 96.1 ± 19.5 μg/kg wet weight (mean ± SD; n = 37) and 84.0 ± 17.6 μg/kg wet weight (n = 40), respectively. Organic pigs had higher Cd levels in manure, indicating a higher Cd exposure from the environment, such as ingestion of soil. Differences in feed compositions and bioavailability of Cd from the feed components may also explain the different kidney levels of Cd.
Organochlorine Pesticide Levels in Maternal Adipose Tissue, Maternal Blood Serum, Umbilical Blood Serum, and Milk from Inhabitants of Veracruz, Mexico by S. M. Waliszewski; A. A. Aguirre; R. M. Infanzon; C. S. Silva; J. Siliceo (pp. 432-438).
Organochlorine pesticides, due to their persistence, accumulate in food chains and cause elevated contamination in human beings. These residues bioconcentrate in lipid-rich tissues according to the equilibrium pattern of internal transport and lipid tissue content. The analyses of maternal adipose tissue, maternal blood serum, umbilical blood serum, colostrum, and mature milk indicate circulation of these compounds through all compartments of the maternal body, including their crossover of the placental barrier. The greatest residue levels found correspond to DDTs, with highest levels determined in colostrum (5.71 mg/kg of DDT total), followed by adipose tissue with 5.66 mg/kg and in mature milk with 4.70 mg/kg. Among DDTs, pp'DDE is the most predominant compound. The paired analyses of organochlorine pesticide residue levels between mother blood serum and umbilical blood serum demonstrate significant correlation and their transfer from mother to fetus through the placenta. The paired analyses of adipose tissue and colostrum and mature milk contamination levels indicate a high degree of coherence, principally of DDT, in the body and lactation as a decontamination means.
Hair Mercury Speciation as a Function of Gender, Age, and Body Mass Index in Inhabitants of the Negro River Basin, Amazon, Brazil by A. C. Barbosa; W. Jardim; J. G. Dórea; B. Fosberg; J. Souza (pp. 439-444).
Human mercury contamination can be monitored through hair analysis of mercury's inorganic and organic form as methylmercury (Me-Hg). Hair total mercury and Me-Hg were studied in a Negro River fish-eating population in relation to age, gender, and body mass index (BMI). This riverbank population eats fish at least twice a day and is exposed to high levels of Me-Hg. Total mercury ranged from 1.51 μg/g to 59.01 μg/g, with only 21% of the sampled population having Hg concentration of less than 10 μg/g hair. The mean percentage of Me-Hg was 71.3% (range 34% to 100%) of the total mercury in hair. No statistically significant differences were found in regard to age groups (children and adults) or BMI. However, women had significantly lower total mercury in hair than men, but the percentage of Me-Hg was not significantly different. Women in fertile age (15–40 years) had hair total mercury ranging from 1.65–32.63 μg/g, and 65% in this subgroup had hair mercury above 10 μg/g hair. The percentage of Me-Hg concentration in hair of this freshwater, fish–eating population is comparable to populations eating ocean fish from different parts of the world and does not seem to be affected by age, gender, and BMI.