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Archives of Environmental Contamination and Toxicology (v.46, #2)
Analysis of the Particles Transported with Dust-Clouds Reaching Cordoba, Southwestern Spain by Paloma Cariñanos; Carmen Galán; Purificación Alcázar; Eugenio Domínguez (pp. 141-146).
Dust-cloud episodes were detected in summer 1999 in the city of Cordoba, southwestern Spain, with a higher frequency than usual. Solid airborne particles were collected using a suction volumetric sampler and analyzed to determine both their nature and their origin. Nonbiological material was mostly identified as mineral sand and partially burned remains of hydrocarbons and stubble. Amounts were estimated in terms of the percentage of microscopic field of view covered. Biological materials, in this case pollen grains, were identified and classified as belonging to either autochthonous or remote flora; in the latter case, the possibility was examined that they might originate in North Africa. Some pollen types were also used as tracers to chart the path followed by the sand clouds within the Iberian Peninsula. Meteorological conditions on the days in which episodes occurred were analyzed. In all cases, very dry southwesterly winds were recorded, at moderate to high speeds, together with temperatures of over 35°C. The increase in airborne pollen detected, together with the large amount of particles collected, could have an adverse effect on health, particularly in pollen allergy sufferers, for whom dust-clouds represent an added risk.
Development, Evaluation, and Application of Sediment Quality Targets for Assessing and Managing Contaminated Sediments in Tampa Bay, Florida by D. D. MacDonald; R. S. Carr; D. Eckenrod; H. Greening; S. Grabe; C. G. Ingersoll; S. Janicki; T. Janicki; R. A. Lindskoog; E. R. Long; R. Pribble; G. Sloane; D. E. Smorong (pp. 147-161).
Tampa Bay is a large, urban estuary that is located in west central Florida. Although water quality conditions represent an important concern in this estuary, information from numerous sources indicates that sediment contamination also has the potential to adversely affect aquatic organisms, aquatic-dependent wildlife, and human health. As such, protecting relatively uncontaminated areas of the bay from contamination and reducing the amount of toxic chemicals in contaminated sediments have been identified as high-priority sediment management objectives for Tampa Bay. To address concerns related to sediment contamination in the bay, an ecosystem-based framework for assessing and managing sediment quality conditions was developed that included identification of sediment quality issues and concerns, development of ecosystem goals and objectives, selection of ecosystem health indicators, establishment of metrics and targets for key indicators, and incorporation of key indicators, metrics, and targets into watershed management plans and decision-making processes. This paper describes the process that was used to select and evaluate numerical sediment quality targets (SQTs) for assessing and managing contaminated sediments. These SQTs included measures of sediment chemistry, whole-sediment and pore-water toxicity, and benthic invertebrate community structure. In addition, the paper describes how the SQTs were used to develop site-specific concentration-response models that describe how the frequency of adverse biological effects changes with increasing concentrations of chemicals of potential concern. Finally, a key application of the SQTs for defining sediment management areas is discussed.
Characterization of Land Contaminated by Past Heavy Metal Mining Using Geostatistical Methods by A. Ersoy; T. Y. Yunsel; M. Cetin (pp. 162-175).
Aspects of mining operations, including production, processing, transportation, and, finally, abandoned mine workings, can undoubtedly cause varying degrees of environmental pollution and contamination. Characterization of the spatial distribution of pollutants in contaminated soil is important for risk assessment and soil remediation. This study has been carried out using both conventional statistics and geostatistical methods which are useful for site assessment, characterization, and monitoring situations where data are collected spatially. These methods are particularly suited to cases where spatial dependence structure and contour maps of contaminant concentration or other variables are needed. The aims of this paper were to determine the extent and severity of the pollution levels on land contaminated by past mining activity through using geostatistical techniques, assess sampling strategy, and interpret data for potentially contaminated land. In the study, a total of 329 soil samples was collected at 1-, 5-, and 10-m regular grid intervals of 100 × 100-m area of Carsington Pasture in the UK and analyzed using an automatic X-ray fluorescence machine for a large number of elements. Only a few elements (Cu, Pb, Zn, and Ba) were subsequently studied in detail because of their association with the mining operation. Directional and omnidirectional experimental semivariograms of elements Cu, Pb, Zn, and Ba for 10-m grid intervals, pooled data of 10- and 5-m grid intervals (S10+5), and pooled data of 10-, 5-, and 1-m grid interval (S10+5+1) showed that neither geometric nor zonal anisotropy exits in the data. The most evident spatial dependence structure of the continuity for omnidirectional experimental semivariogram, characterized by a spherical model, of each element was obtained for the pooled data set of S10+5. Pooling 1-m grid data to S10+5 shaded the spatial dependence structure. The spherical model adopted for each element embodied no nugget effect, indicating that mineralization did not occur as nuggets in the study area, but it did show different ranges of influence and sill values. Spherical semivariogram model of each element for the pooled data set of S10+5 passed the cross validation tests. Graphs of cross validation test results proved that the isotropic spherical model, with its parameters and kriging search parameters, is representative for the area under study. The values of 10,000 grid nodes established regularly over the study area were estimated by kriging interpolation technique to smooth out the contours. Kriged maps for the Cu, Pb, Zn, and Ba elements were plotted. Anomalies such as bull’s-eyes and drift did not observed in the maps generated. Contour maps of estimated element concentrations revealed the extent and severity of contamination. Spatial distribution maps of the elements might be used in the remediation studies and help decision-makers and others involved in the abandoned heavy metal mining site in the UK.
Effect of pH on Arsenate and Arsenite Toxicity to Luminescent Bacteria (Vibrio fischeri) by E. Fulladosa; J. C. Murat; M. Martínez; I. Villaescusa (pp. 176-182).
Arsenic is an abundant metalloid and a dangerous pollutant when in solution under the arsenate or arsenite forms—As(V) and As(III), respectively. Since its biological effects are expected to depend on the oxidation state and on speciation, effect of pH on either As(V) or As(III) speciation and resulting toxicity was investigated using the Microtox bioassay based on change in light emission by the luminescent bacteria Vibrio fischeri. Within a 5.0–8.0 pH range, EC50 values for As(V) were found to decrease as pH became basic, reflecting an increase in toxicity; whereas in the case of As(III), EC50 values were almost unchanged within a 6.0–8.0 pH range and lowered only at pH 9.0. HAsO42− and H2AsO3− were found to be the most toxic species. A statistical approach based on testing the null hypothesis of additive toxicity revealed an antagonistic effect between the arsenate chemical species. At low concentrations, As(V) was regularly found to be more toxic than As(III), independent of the pH value. Conversely, at high concentrations, the toxicity of both As(III) and As(V) was found to chiefly depend on pH, as a consequence of the strong influence of this parameter on the chemical speciation.
Effect of Bile Type on the Bioaccessibility of Soil Contaminants in an In Vitro Digestion Model by A. G. Oomen; C. J. M. Rompelberg; E. Van de Kamp; D. P. K. H. Pereboom; L. L. De Zwart; A. J. A. M. Sips (pp. 183-188).
Soil ingestion is an important pathway of exposure for many nonvolatile contaminants for man and in particular for children. A fraction of the ingested contaminant may not dissociate from the soil particles during digestion in the gastro-intestinal tract, and is thus not available for transport across the intestinal epithelium. In order to estimate the contaminant fraction that is mobilized from soil, i.e., the bioaccessible fraction, several in vitro digestion models have been developed. The currently existing digestion models display many differences. One aspect that may affect bioaccessibility and may induce differences between digestion models is the bile that is used. Often freeze-dried bile of animal origin is preferred to purified bile salts. However, also the animal origin of bile may give rise to differences in bioaccessibility because bile composition appears to be species dependent. In the present study, we compared the bioaccessibility of benzo[a]pyrene, arsenic, cadmium, and lead of four different soils after digestion with ox bile from two different suppliers, pig bile, and chicken bile. Bioaccessibility appeared to vary amongst the different soils and contaminants. Only chicken bile increased the bioaccessibility of lead and cadmium significantly and relevantly for one of four soils. For chicken bile, the bioaccessibility of lead was 3–5.5 times greater than for the other bile types and the bioaccessibility of cadmium was 1.5 times greater. In all other cases, the bioaccessibility differences were less than 10%, which is considered irrelevant for risk assessment purposes.
Screening Processed Milk for Volatile Organic Compounds Using Vacuum Distillation/Gas Chromatography/Mass Spectrometry by M. H. Hiatt; J. H. Pia (pp. 189-196).
An adaptation is presented of method 8261—from the Office of Solid Waste and Emergency Response Test Methods for Evaluating Solid Waste Physical/Chemical Methods (SW-846)—to analyze milk for an expanded list of volatile organic compounds is presented. The milk matrix exhibits a strong affinity for organic compounds and the surrogate based matrix normalization described in method 8261 provided accurate results. This method had the sensitivity necessary to detect volatile organic analytes at or below maximum contaminant levels (MCLs) set by EPA for drinking water. In a survey of milk samples available in Las Vegas, Nevada, 32 of 88 targeted volatile organic compounds (VOCs) were detected. Many of the detected VOCs have not previously been reported and a rationale for their presence in milk is presented.
First Report of a Microcystin-Containing Bloom of the Cyanobacteria Microcystis spp. in Lake Oubeira, Eastern Algeria by Aïcha-Beya Nasri; Noureddine Bouaïcha; Jutta Fastner (pp. 197-202).
Lake Oubeira has been used as the main source of drinking water for many communities in the East of Algeria. In this lake, nutrient loading coupled with year-round warm weather favors the growth of cyanobacteria, several of which can produce cyanotoxins, especially the potent liver toxins called microcystins (MCYSTs). The present study evaluated microcystin levels and characterized the different microcystin variants present in the raw water during a 17-month period (April 2000–September 2001), as measured by protein phosphatase inhibition assays and by matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry, respectively. The results showed that microcystin concentrations in the lake water varied between 3 and 29,163 μg microcystin-LR equivalent per liter. The microscopic examination of the phytoplankton samples showed the dominance of the Microcystis genus in the cyanobacterial bloom. The highest MCYST concentration was observed in August 2001, at 29,163 μg/l. Therefore, the highest total MCYST content per phytoplankton biomass was found in August 2001, with 4,590 μg MCYST-LR equivalents/g dried bloom material. Analysis of the field bloom extract by MALDI-TOF mass spectrometry demonstrated the presence of four variants of microcystins: microcystin-LR (MCYST-LR), microcystin-YR (MCYST-YR), microcystin-RR (MCYST-RR), and a demethylated variant of MCYST-LR (D-MCYST-LR).
Ten-Year Viability Study on Natural Populations of Drosophila Sibling Species from Laguna Verde, Veracruz, México by E. Pimentel; M. P. Cruces; V. M. Salceda; M. E. de la Rosa; L. Levine; J. A. Castillo (pp. 203-207).
The generation of electricity in nuclear power plants produces an increase in background radiation that could possibly have some impact on the organisms that live in that area. In order to identify and quantify any such possible effect, the natural populations of two sibling species, D. melanogaster and D. simulans, that live in the immediate vicinity of the first Mexican Nuclear Power Plant were analyzed for a period of 10 years. Collections of flies were made at two sites, one close to and one farther from the power plant, during the pre and operational stages of the reactor, and their egg-to-adult viability was analyzed. The data obtained indicate that in both sites, the egg-to-adult viability was generally higher in D. melanogaster than in D. simulans. Further, a relationship was found between egg-to-adult viability and the season of the year (warm–wet or cool–dry season). Some differences were found between the two sites. It may be concluded that there is no negative impact on the Drosophila populations studied.
The Comet Assay as Biomarker of Heavy Metal Genotoxicity in Earthworms by S. A. Reinecke; A. J. Reinecke (pp. 208-215).
The ubiquitous occurring earthworm species, Eisenia fetida, were exposed to nickel chloride to determine whether the heavy metal Ni caused DNA damage, as measured by the comet (single cell gel electrophoresis) assay. Primary cell cultures of earthworm coelomocytes were exposed in vitro and whole animals either in spiked artificial soil water or in spiked cattle manure substrates. Comets formed were scored using mean tail lengths as well as comparing percentages of damage in five different damage classes. The exposure concentrations used for the in vitro exposure (2, 6, and 12 μg/ml) caused the formation of comets of which the mean tail lengths differed significantly (p < 0.05) from those of unexposed controls but not from each other. Coelomocytes from worms exposed in artificial soil water at concentrations of 0.0049, 0.0078, 0.0175, and 0.025 mg/ml formed comets of which the mean tail lengths differed significantly (p < 0.05) between the exposure groups with increasingly longer tail lengths with higher concentration (dose-related response). The tail length means of the comets of the three highest exposure concentrations also differed significantly (p < 0.05) from the controls. No dose-related response was found between comet tail lengths of the three exposure concentrations (60, 240, and 480 mg/kg) used for the worms in the cattle manure substrates, but the mean tail lengths of comets from all three exposure groups differed significantly (p > 0.05) from the controls. The comets formed in cells from animals exposed in artificial soil water and in cattle manure substrates, scored within damage classes, indicated a clear shift with increasing exposure concentrations from low to high damage. Our results indicated DNA single-strand breaks in soil invertebrate cells caused by exposure to a nickel compound, verifying previous findings for mammals which indicated that this heavy metal has genotoxic potential. These results therefore suggest that earthworms may be useful indicator organisms to assess the genotoxic risks of nickel pollution to terrestrial environments and that the comet assay is a useful tool to use as biomarker of genotoxic effects on invertebrates in soil.
A Comparison of Two Factorial Designs, a Complete 3×3 Factorial and a Central Composite Rotatable Design, for Use in Binomial Response Experiments in Aquatic Toxicology by Andrea N. Edginton; Patrick M. Sheridan; Herman J. Boermans; Dean G. Thompson; John D. Holt; Gerald R. Stephenson (pp. 216-223).
Using an amphibian toxicity testing protocol, comparative studies were conducted to assess the predictive precision, degree of similarity of results and efficiency of a central composite rotatable design (CCRD) in relation to a conventional complete 3×3 factorial design. Data were treated with response surface analysis using generalized linear models (glm) and application of profile deviance to generate confidence intervals. Design comparisons were based on studies conducted using the Frog Embryo Teratogenesis Assay—Xenopus (FETAX) protocol to examine the interaction of three toxicants at pH levels ranging from 4.5 to 8.5. Test substances included two commercial herbicide formulations based on glyphosate ([N-phosphonomethyl]glycine) isopropylamine salt (Vision, Rodeo) as well as a polyethoxylated tallow amine surfactant blend (MON 0818), which is a key component of the Vision formulation. The generated models from both the CCRD and the factorial designs produced toxicity estimates similar to each other and to previously published results. Trends were also similar to published results in that the surfactant, MON 0818, was comparatively more toxic than Vision, which was more toxic than Rodeo. Further, all toxicants induced higher mortality under alkaline as opposed to acidic conditions. The CCRD was between 66 and 124% more efficient in the Vision and Rodeo experiments in comparison to the complete 3×3 factorial. Thus, the factorial experiment would have required at least 66% more observations to obtain the same precision. There appeared to be no efficiency gain with the use of the CCRD for MON 0818. The CCRD had tighter confidence intervals in 9 of 12 cases across all test substances. Computer simulations using the experimental data for Vision demonstrated that the LCα estimates generated from the 1,000 simulated data sets were very close to the “true” value for both designs. This was based on small bias and mean squared error calculations. Coverage probabilities in both designs were between 91.6 and 95.6%, close to the nominal coverage of 95%. Efficiency comparisons of the simulated Vision data sets demonstrated that the CCRD was more efficient in 93.3% of the comparisons. We suggest that a CCRD using glm and profile deviance for statistical analyses be considered an effective and efficient alternative in toxicity studies where interactive effects are of interest.
Biosensors of Inorganic Lead Exposure and Effect in an Adult Amphibian by Marcos A. Arrieta; Liliana Bruzzone; Carina Apartín; Carolina E. Rosenberg; Nilda E. Fink; Alfredo Salibián (pp. 224-230).
Lead (Pb) is a ubiquitous environmental pollutant, widely distributed, representing a high toxicological and ecotoxicological risk. Several morphological, functional, and biochemical parameters have been proposed as biomarkers of effect and exposure to Pb. The information related to adverse effects of Pb is not abundant for adult amphibians. These animals are of interest, because during their development they move from aquatic to terrestrial habitats, which may be polluted by the metal since they are receptors of products generated by anthropogenic activities. Previous studies carried out on the adult South American toad Bufo arenarum (Amphibia, Anura) showed that it has a high tolerance to lead and studied the effect of sublethal doses of the metal on the erythrocyte osmotic fragility and δ-ALAD activity. It was also shown that after a single injection of Pb, a significant increase in the number of reticulocytes was produced, suggesting the suitability of those cell counts as a biomarker of exposure to the metal; its impact on the immune system of the toads was also studied. In this work we extend our early studies on the same species evaluating the chronic effect of sublethal Pb (equivalent to 5.6% of the 120-h LD-50) on free erythrocyte protoporphyrin (FEP) and blood Pb and δ-ALAD activity; blood lead was positively associated with a significant decrease in the enzyme activity and to an increase in the FEP level. Pb concentration in target organs (liver, spleen, femur, and kidney) and the total cumulated amount as well as its impact over the mass of those organs were also determined. In addition, the magnitude of the possible depuration through urine and intestine was evaluated. Our results showed that FEP, δ-ALAD, and blood Pb are reliable biosensors of chronic metal intoxication, the former being the marker with the highest sensitivity.
Effects of Cooking on Radiocesium in Fish from the Savannah River: Exposure Differences for the Public by Joanna Burger; Karen F. Gaines; C. Shane Boring; J. Snodgrass; W. L. Stephens Jr.; M. Gochfeld (pp. 231-235).
Understanding the factors that contribute to the risk from fish consumption is an important public health concern because of potential adverse effects of radionuclides, organochlorines, other pesticides, and mercury. Risk from consumption is normally computed on the basis of contaminant levels in fish, meal frequency, and meal size, yet cooking practices may also affect risk. This study examines the effect of deep-frying on radiocesium (137Cs) levels and risk to people fishing along the Savannah River. South Carolina and Georgia have issued consumption advisories for the Savannah River, based partly on 137Cs. 137Cs levels were significantly higher in the cooked fish compared to the raw fish on a wet weight basis. Mean 137Cs levels were 0.61 pCi/g (wet weight basis) in raw fish, 0.81 pCi/g in cooked–breaded, and 0.99 pCi/g in cooked–unbreaded fish. Deep-frying with and without breading resulted in a weight loss of 25 and 39%, while 137Cs levels increased by 32 and 62%, respectively. Therefore, the differences were due mainly to weight loss during cooking. However, the data suggest that risk assessments should be based on cooked portion size for contaminant analysis, or the risk from 137Cs in fish will be underestimated. People are likely to estimate the amounts of fish they eat based on a meal size of the cooked portion, while risk assessors determine 137Cs levels in raw fish. A conversion factor of at least two for 137Cs increase during cooking is reasonable and conservative, given the variability in 137Cs levels. The data also suggest that surveys determining consumption should specifically ask about portion size before or after cooking and state which was used in their methods.
Influences on Mercury Bioaccumulation Factors for the Savannah River by M. H. Paller; J. A. Bowers; J. W. Littrell; A. V. Guanlao (pp. 236-243).
Mercury TMDLs (Total Maximum Daily Loads) are a regulatory instrument designed to reduce the amount of mercury entering a water body and ultimately to control the bioaccumulation of mercury in fish. TMDLs are based on a BAF (bioaccumulation factor), which is the ratio of methyl mercury in fish to dissolved methyl mercury in water. Analysis of fish tissue and aqueous methyl mercury samples collected at a number of locations and over several seasons in a 118-km reach of the Savannah River demonstrated that species-specific BAFs varied by factors of three to eight. Factors contributing to BAF variability were location, habitat, and season-related differences in fish muscle tissue mercury levels and seasonal differences in dissolved methyl mercury levels. Overall (all locations, habitats, and seasons) average BAFs were 3.7 × 106 for largemouth bass, 1.4 × 106 for sunfishes, and 2.5 × 106 for white catfish. Determination of representative BAFs for mercury in fish from large rivers necessitates collecting large and approximately equal numbers of fish and aqueous methyl mercury samples over a seasonal cycle from the entire area and all habitats to be represented by the TMDL.
Morphological and Neurotoxicological Findings in Tropical Freshwater Fish (Astyanax sp.) After Waterborne and Acute Exposure to Water Soluble Fraction (WSF) of Crude Oil by F. M. Akaishi; H. C. Silva de Assis; S. C. G. Jakobi; D. R. Eiras-Stofella; S. D. St-Jean; S. C. Courtenay; E. F. Lima; A. L. R. Wagener; A. L. Scofield; C. A. Oliveira Ribeiro (pp. 244-253).
The water-soluble fraction (WSF) of crude oil is a complex highly volatile and toxic mixture of hydrocarbon chains (polyaromatics, heterocyclics), phenols, and heterocyclic compounds containing nitrogen and sulfur. To evaluate the toxic effects of WSF in tropical freshwater teleosts and to develop methodologies that could investigate the toxic mechanisms of WSF in tropical organisms, an acute toxicity experiment was conducted with Astyanax sp. Three dilutions (15%, 33%, and 50%) of WSF obtained from Campos Bay’s crude oil (Brazil) were used to study morphological and biochemical responses of the fish. Prior to exposure, the distribution and rate of volatilization of the WSF into each aquarium for the same exposure period was quantified by spectrofluorimetry. Five individuals of Astyanax sp. were exposed to duplicate WSF of 0, 15, 33, and 50% for each of 12-, 24-, and 96-h exposures for a total of 120 individuals. Liver and gills were sampled from five fish from each treatment and were analyzed by histology, scanning and transmission electron microscopy. A fragment of muscle was also collected from each fish to measure acetylcholinesterase activity. Water analysis showed that only 4 h after dilution, an important loss of hydrocarbons in 33% and 50% of WSF was observed. In addition, 50% of hydrocarbon mass was lost in all tested dilutions after 24 h with significant difference for the 50% WSF at all measured times, demonstrating the high volatility of WSF in freshwater. Damage in the liver and the gills included the presence of necrosis, loss of hepatocytes limit, inflammation areas, cellular proliferation, aneurysms, and disorganization of the second lamellae. The 33% WSF significantly reduced acetylcholinesterase activity in fish. Our study demonstrated that the WSF of crude oil caused damage in organs and tissues of tropical freshwater Astyanax sp. and provided also the basis for a better understanding of the toxic mechanisms of WSF in freshwater fishes.
Organochlorine Contaminants in Loggerhead Sea Turtle Blood: Extraction Techniques and Distribution Among Plasma and Red Blood Cells by J. M. Keller; J. R. Kucklick; P. D. McClellan-Green (pp. 254-264).
Few studies have described the organochlorine (OC) contaminant concentrations found in sea turtle tissues. These studies have relied on the opportunistic sampling of either eggs or tissues from stranded carcasses. In this study, the use of whole blood samples as well as both blood components (plasma and red blood cells) were examined as a non-destructive alternative for monitoring OCs in free-ranging loggerhead sea turtles (Caretta caretta). Blood samples were collected from juvenile loggerhead sea turtles (n = 12) captured in Core Sound, North Carolina, USA and analyzed for 55 polychlorinated biphenyl (PCB) congeners and 24 OC pesticides by gas chromatography with electron capture detection and mass spectrometry. Using pooled loggerhead sea turtle whole blood, three different liquid:liquid extraction techniques were compared. Results were similar in terms of recovery of internal standards, lipids, and OC concentrations. An extraction technique, employing formic acid and 1:1 methyl-tert-butyl-ether:hexane, was found to be satisfactory. This method was applied to the extraction of OCs from whole blood, plasma, and red blood cell (RBC) samples from five loggerhead sea turtles. Plasma contained the highest OC concentrations on a wet mass basis, followed by whole blood and RBCs. The majority of each OC compound was found in the plasma rather than the RBCs, suggesting that OC compounds preferentially partition into the plasma. On average (SD), 89.4% (3.1%) of total PCBs, 83.4% (11.9%) of total chlordanes, 74.3% (15.1%) of mirex, 72.6% (4.8%) of total DDTs, and 80.1% (16.6%) of dieldrin were found in the plasma. The concentrations of total PCBs, mirex, total chlordanes, and total DDTs measured in both components of the blood significantly correlated to those in whole blood. These are the first reported OC concentrations in sea turtle blood. They were found to be similar to previously reported levels in blood components of humans and of reptiles from relatively clean sites, but lower than those measured in blood of fish-eating birds and marine mammals. The results indicate that blood, preferably plasma, can be used to detect and monitor OC contaminants in loggerhead sea turtles.
Endocrine-Disrupting Compounds and Mixtures: Unexpected Dose–Response by Emily Willingham (pp. 265-269).
The current study examined the effects on the red-eared slider turtle of extremely low doses of three endocrine-disrupting compounds (EDCs)—trans-Nonachlor, chlordane, and p,p′-DDE—singly and in mixtures. Previous studies using the red-eared slider turtle have proven its value as an organism for obtaining information about the effects of endocrine-disrupting compounds. The sex of the turtle, easily manipulated by exposure during embryogenesis, continues to be a marker of effects. When red-eared slider turtle embryos incubating at a temperature that normally produces a male-biased sex ratio are exposed to these compounds singly, the sex ratio of the resulting hatchlings shifts significantly to a female bias. The current work offers further evidence that the red-eared slider turtle provides a way to quantify the effects of mixtures and has the potential as a model for evaluating additivity and synergy. The results provide information about how very low doses (parts per billion) of these compounds behave in mixtures. The dose ranges were 0.125–0.5 ng/egg for trans-Nonachlor and chlordane and 7–28 ng/egg for p,p′-DDE. Results suggest the possibility that two of the compounds may exert effects in mixtures via complementary pathways; when applied singly, the effects of chlordane and p,p′-DDE were inversely related to dose, but in mixtures, which were essentially a greater dose of EDC, the compounds had an increased effect. In all cases, mixtures resulted in 100% females.
Organochlorines in Black-Crowned Night Heron (Nycticorax nycticorax) Eggs Reflect Persistent Contamination in Northeastern US Estuaries by A. C. Matz; K. C. Parsons (pp. 270-274).
Colonially nesting aquatic birds can indicate site-specific contamination because they are high-level predators and dependent upon local resources during the breeding season. We compared persistent organochlorine concentrations in black-crowned night heron (Nycticorax nycticorax) eggs collected in 1992–93 among areas of known contamination (New York Harbor, Boston Harbor, Cape Cod, and Delaware Bay) and a reference site (Nantucket Island) in the northeastern United States (7–16 eggs/site). Total PCBs, p,p′-DDE, oxychlordane, heptachlor epoxide, and trans-nonachlor were detected in most eggs and were significantly higher in New York Harbor compared to all other sites (ANOVA on factor scores from the first principal component, which accounted for 75% of data variance, p < 0.0001). New York also had the highest contamination index (the number of Superfund sites within 20 km of the colony) among the sites. Nantucket, the reference site, had consistently low contamination in eggs, and the lowest contamination index. We conclude that black-crowned night heron eggs are useful indicators of site-specific persistent organochlorine contamination, as indexed by the number of nearby Superfund sites.
The Effect of Dietary Arsenic Additions on the Distribution of Selenium and Iodine in Eggs and Tissues of Laying Hens by V. Stibilj; R. Vadnjal; M. Kovač; A. Holcman (pp. 275-280).
The aim of the work was to determine the short-term effect (19 days) of dietary As additions (30 μg As/g in the form As2O3) on the Se and I concentrations in eggs and tissues of 49-week-old Rhode Island Red laying hens. Se and I concentrations were determined in eggs collected from the 8th to the 10th and from the 17th to the 19th days of the experiment. After 19 days, blood was collected by anterior heart puncture, and after slaughter the liver, kidney, lung, muscle (musculus pectoralis superficialis) and feathers were collected. Se and I concentrations were determined by radiochemical neutron activation analysis and the results expressed on a dry matter basis. In the control and the exposed group, the highest Se concentrations were found in kidney, followed by liver, blood, lung, muscle, and feathers. In the control group the highest I concentration was found in feathers, followed by kidney, blood, lungs, liver, and muscle. In the trial group, the order was almost the same, except that blood concentration was lower than in liver. As2O3 added to the feed significantly increased the Se concentration in the lung (p = 0.0216), I concentration in muscle (p = 0.0112) and significantly decreased I concentration in blood (p = 0.0371). It had no effect on the concentrations of Se and I in egg yolk and white.