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Archives of Environmental Contamination and Toxicology (v.35, #2)
Assessing Sediment Toxicity from Navigational Pools of the Upper Mississippi River Using a 28-Day Hyalella azteca Test by N. E. Kemble; E. L. Brunson; T. J. Canfield; F. J. Dwyer; C. G. Ingersoll (pp. 181-190).
To assess the extent of sediment contamination in the Upper Mississippi River (UMR) system after the flood of 1993, sediment samples were collected from 24 of the 26 navigational pools in the river and from one site in the Saint Croix River in the summer of 1994. Whole-sediment tests were conducted with the amphipod Hyalella azteca for 28 days measuring the effects on survival, growth, and sexual maturation. Amphipod survival was significantly reduced in only one sediment (13B) relative to the control and reference sediments. Body length of amphipods was significantly reduced relative to the control and reference sediments in only one sample (26C). Sexual maturation was not significantly reduced in any treatment when compared to the control and reference sediments. No significant correlations were observed between survival, growth, and maturation to either the physical or chemical characteristics of the sediment samples from the river. When highly reliable effect range medians (ERMs) were used to evaluate sediment chemistry, 47 of 49 (96%) of the samples were correctly classified as nontoxic. These results indicate that sediment samples from the Upper Mississippi River are relatively uncontaminated compared to other areas of known contamination in the United States.
Assessing the Bioaccumulation of Contaminants from Sediments of the Upper Mississippi River Using Field-Collected Oligochaetes and Laboratory-Exposed Lumbriculus variegatus by E. L. Brunson; T. J. Canfield; F. J. Dwyer; C. G. Ingersoll; N. E. Kemble (pp. 191-201).
Concern with the redistribution of contaminants associated with sediment in the upper Mississippi River (UMR) arose after the flood of 1993. This project is designed to evaluate the status of sediments in the UMR and is one article in a series designed to assess the extent of sediment contamination in navigational pools of the river. Companion articles evaluate sediment toxicity and benthic community composition in navigation pools of the river. The objectives of the present study were to: (1) to assess the bioaccumulation of sediment-associated contaminants in the UMR using laboratory exposures with the oligochaete Lumbriculus variegatus, and (2) to compare bioaccumulation in laboratory-exposed oligochaetes to field-collected oligochaetes. Sediment samples and native oligochaetes were collected from 23 navigational pools on the Upper Mississippi River and the Saint Croix River. Contaminant concentrations measured in the L. variegatus after 28-day exposures to sediment in the laboratory were compared to contaminant concentrations in field-collected oligochaetes from the 13 pools where these sediments were collected. Contaminant concentrations were relatively low in sediments and tissues from the pools evaluated. Only polycyclic aromatic hydrocarbons (PAHs) and total polychlorinated biphenyls (PCBs) were frequently measured above detection limits. The majority of the biota-sediment-accumulation factors (BSAFs) for PAHs were within a range of about 1.0 to 2.6, suggesting that the theoretical BSAF value of 1.7 could be used to predict these mean BSAFs with a reasonable degree of certainty. A positive correlation was observed between lipid-normalized concentrations of PAHs detected in laboratory-exposed and field-collected oligochaetes across all sampling locations. Rank correlations for concentrations of individual compounds between laboratory-exposed and field-collected oligochaetes were strongest for benzo(e)pyrene, perylene, benzo(b,k)fluoranthene, and pyrene. About 90% of the paired PAH concentrations in laboratory-exposed and field-collected oligochaetes were within a factor of three of one another indicating laboratory results could be extrapolated to the field with a reasonable degree of certainty.
Assessing Sediments from Upper Mississippi River Navigational Pools Using a Benthic Invertebrate Community Evaluation and the Sediment Quality Triad Approach by T. J. Canfield; E. L. Brunson; F. J. Dwyer; C. G. Ingersoll; N. E. Kemble (pp. 202-212).
Benthic invertebrate samples were collected from 23 pools in the Upper Mississippi River (UMR) and from one station in the Saint Croix River (SCR) as part of a study to assess the effects of the extensive flooding of 1993 on sediment contamination in the UMR system. Sediment contaminants of concern included both organic and inorganic compounds. Oligochaetes and chironomids constituted over 80% of the total abundance in samples from 14 of 23 pools in the UMR and SCR samples. Fingernail clams comprised a large portion of the community in three of 23 UMR pools and exceeded abundances of 1,000/m2 in five of 23 pools. Total abundance ranged from 250/m2 in samples from pool 1 to 22,389/m2 in samples from pool 19. Abundance values are comparable with levels previously reported in the literature for the UMR. Overall frequency of chironomid mouthpart deformities was 3% (range 0–13%), which is comparable to reported incidence of deformities in uncontaminated sediments previously evaluated. Sediment contamination was generally low in the UMR pools and the SCR site. Correlations between benthic measures and sediment chemistry and other abiotic parameters exhibited few significant or strong correlations. The sediment quality triad (Triad) approach was used to evaluate data from laboratory toxicity tests, sediment chemistry, and benthic community analyses; it showed that 88% of the samples were not scored as impacted based on sediment toxicity, chemistry, and benthic measures. Benthic invertebrate distributions and community structure within the UMR in the samples evaluated in the present study were most likely controlled by factors independent of contaminant concentrations in the sediments.
Toxicity of Sediment Collected Upriver and Downriver of Major Cities Along the Lower Mississippi River by P. V. Winger; P. J. Lasier (pp. 213-217).
The Lower Mississippi River contributes significantly to the biodiversity and ecological stability of the alluvial valley, but agricultural, industrial, and municipal developments have historically impacted environmental quality of the river. Toxicity of sediment and sediment pore water was used to assess the current effects of major cities on sediment quality along the Lower Mississippi River. Composite sediment samples were collected from four sites upriver and four sites downriver of five major cities: Cairo, IL; Memphis, TN; Vicksburg, MS; Baton Rouge, LA; and New Orleans, LA. Acute toxicity was determined by exposing Hyalella azteca to solid-phase sediment for 10 days with two water renewals per day and to sediment pore water under static conditions for 96 h. After the initial tests, animals were exposed to ultraviolet light for 16 h. Sediments were analyzed for organics (organochlorine pesticides, PCBs, organophosphate insecticides, and PAHs) and metals (Cr, Cu, Pb, Mn, Ni, Zn). With the exception of upriver from Memphis, solid-phase sediments were not toxic to H. azteca. Pore water from sediments collected upriver of Memphis also showed slight toxicity. Exposure of H. azteca to ultraviolet light did not increase the toxicity of the sediment or pore-water samples, indicating a lack of toxicity from PAHs that are photoactivated by ultraviolet light. Chemical analyses did not reveal any contaminant levels of concern in the sediments. Based on toxicity testing and chemical analyses, quality of sediments collected from the Lower Mississippi was good, with the exception of sites sampled upriver of Memphis.
Organochlorine Pesticides and Enantiomers of Chiral Pesticides in Arctic Ocean Water by L. M. M. Jantunen; T. F. Bidleman (pp. 218-228).
In the summers of 1993 and 1994, seawater samples from the surface layer (40–60 m) were collected to determine the spatial distribution of organochlorine pesticides on expeditions that crossed the Arctic Ocean from the Bering and Chukchi seas to the North Pole, to a station north of Spitsbergen, and then south into the Greenland Sea. Spatial differences in concentration were found that varied with the pesticide. Heptachlor exo-epoxide (a metabolite of heptachlor) and α-hexachlorocyclohexane (α-HCH) increased from the Chukchi Sea to the pole, and then decreased toward Spitsbergen and Greenland Sea. Chlorinated bornanes (toxaphene) followed a similar trend, but levels were also high near Spitsbergen and in the Greenland Sea. A reverse trend was found for endosulfan, with lower concentrations in the ice-covered regions. Little variation was seen in chlordane concentrations, although the ratio of trans-/cis-chlordane decreased at high latitudes. Several of these pesticides are chiral: α-HCH, cis- and trans-chlordane, and heptachlor exo-epoxide. Enantioselective degradation of (−)α-HCH was found in the Bering and Chukchi seas, whereas the (+) enantiomer was depleted in the Arctic Ocean and Greenland Sea. Enrichment of (+) heptachlor exo-epoxide was found in all regions. Trans- and cis-chlordane were nearly racemic.
The Use of Lipid Metabolic Profiling to Assess the Biological Impact of Marine Sewage Pollution by E. L. Avery; R. H. Dunstan; J. A. Nell (pp. 229-235).
Sydney rock oysters, Saccostrea commercialis, were deployed for a 3-month period at sewage-disturbed and control marine locations in the Hunter Region, New South Wales, Australia. After this period, the oysters were retrieved and the gills dissected and extracted for analysis of the saponified lipid components (including fatty acids and sterols), using gas chromatography-mass spectrometry (gc-ms). Multivariate analysis (discriminant function) of the gc-ms lipid profiles indicated that the lipid homeostasis in oysters from the sewage locations was significantly different compared with that observed in oysters from control locations (p < 0.0001). The primary factor discriminating between sewage and control locations was the level of β-sitosterol, a plant sterol derived from domestic sewage and marine algae. The results indicate that gill lipid metabolism differentially alters in response to deployment of oysters into either sewage-contaminated or control locations. This method of analysis provides a sensitive measure for the biological impact of composite waste cocktails on strategically located marker organisms in affected environments.
Experimental Induction of Morphological Deformities in Chironomus riparius Larvae by Chronic Exposure to Copper and Lead by L. Janssens de Bisthoven; A. Vermeulen; F. Ollevier (pp. 249-256).
Five consecutive generations of Chironomus riparius Meigen larvae were chronically exposed from egg to fourth instar to four sublethal concentrations of copper (0, 1, 10, 100 μg L−1) and lead (0, 5, 50, 500 μg L−1) in artificially spiked water (static with renewal), with diatomaceous earth as substrate and tetraphyl® as food, in order to test the induction of morphological deformities by these metals. The use of diatomaceous earth was suboptimal because it caused high mortalities (>60%), independent of metal stress. The higher copper concentrations had a positive effect on the survivals relative to the control. Split medial mentum teeth were recorded in more than 10% of the larvae, but could not be related to metal stress. Deformities of the mentum and the mandibles were recorded in second, third, and fourth instars exposed to both metals. Concentration and generation effects were noted for unusual number of mentum teeth (0–5.3%, lead), unusual number of mandible inner teeth (0–10.4%, copper and lead), and small open mentum gap (0–6.5%, copper). These experiments demonstrated the potential of both an essential and a non-essential metal to induce weak deformities in a small proportion of a C. riparius population as well as the induction of deformities which are independent of metal stress or fluctuating over the generations. The study shows the potential of midge deformities as a biomonitoring tool, but at the same time warns for a careful interpretation of deformity scores because of the influence of population dynamics on the final outcome of deformity frequencies and of the existence of deformities not related to pollution.
Polycyclic Aromatic Hydrocarbons in Freshwater Isopods and Field-Partitioning Between Abiotic Phases by B. van Hattum; M. J. Curto Pons; J. F. Cid Montañés (pp. 257-267).
An assessment was made of the in situ bioaccumulation of 13 polycyclic aromatic hydrocarbons (PAHs) in freshwater isopods in relation to their partitioning between sediments, particulate matter (>0.7 μm), and dissolved phases in eight different water systems of The Netherlands. Large differences in total (Γ PAHs) concentrations and in relative abundance of individual PAHs were observed between organisms and abiotic compartments and among sampling stations. Principal component analysis revealed distinct differences between PAH profiles in sediments and water. High molecular weight PAHs dominated in the sediments, fluoranthene and pyrene in the isopods, and naphthalene in water. Apparent lipid-based bioconcentration factors (BCFs) increased with increasing hydrophobicity (n-octanol/water partition coefficient; Kow). The total range of the BCFs varied only one order of magnitude, ranging from 105.1 (naphthalene) to 106.1 (benzo[a]pyrene). For PAHs with log Kow > 6.1 lower BCFs than expected were observed, which was attributed to reduced bioavailability, to the operational definition of the dissolved phase, and to growth dilution preventing equilibrium to be reached within the lifetime of the isopods. Abiotic partitioning coefficients, such as Koc (organic carbon normalized sediment–water partition coefficient) and Kpm (particulate matter–water distribution coefficient) increased with hydrophobicity for PAHs having a log Kow < 6.1. Sediment-water partition coefficients (Kd) increased with the organic carbon content of the sediments for most PAHs. It is concluded that isopods have a marked ability to accumulate PAHs and that their tissue residues tend to reflect spatial and temporal variations in the bioavailability of PAHs in littoral freshwater environments.
Effects of Salinity and Temperature on the Bioavailability of Dispersed Petroleum Hydrocarbons to the Golden-Brown Algae, Isochrysis galbana by M. F. Wolfe; G. J. B. Schwartz; S. Singaram; E. E. Mielbrecht; R. S. Tjeerdema; M. L. Sowby (pp. 268-273).
Comparative studies were done to determine the influence of a dispersant on the bioavailability of naphthalene from crude oil to the unicellular golden-brown algae, Isochrysis galbana, under changing temperature and salinity conditions. Conditions were selected to represent a range (two temperatures, 12 and 20°C, and two salinities, 22 and 34‰) encountered in Pacific waters, where extensive crude oil transport and refining occurs. Cells were exposed to laboratory preparations of either the water-accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO) or a dispersed oil (DO) mixture of PBCO and Corexit 9527® spiked with [U-14C]naphthalene. Uptake increased by as much as 50% in DO, 20°C exposures run at 22‰ (0.24 μmol naphthalene/g algae in WAF, 0.37 μmol naphthalene/g algae in DO) compared with comparable exposures at 34‰ (0.23 μmol naphthalene/g algae in WAF, 0.37 μmol naphthalene/g algae in DO). A 24-h bioaccumulation factor (BAF) calculated in the absence of steady state indicated increasing bioaccumulation with decreasing temperature. No significant variation in relative metabolite composition occurred under the different experimental conditions. Results of these experiments showed that the use of dispersants enhanced the uptake of naphthalene by microalgae under a variety of temperature and salinity conditions, independent of aqueous concentration.
Influence of Dispersants on the Bioavailability of Naphthalene from the Water-Accommodated Fraction Crude Oil to the Golden-Brown Algae, Isochrysis galbana by M. F. Wolfe; G. J. B. Schwartz; S. Singaram; E. E. Mielbrecht; R. S. Tjeerdema; M. L. Sowby (pp. 274-280).
The golden-brown algae Isochrysis galbana, a primary producer, was used to determine the influence of the chemical dispersing agent, Corexit 9527®, on the bioavailability of naphthalene. Cells were exposed to laboratory preparations of either the water-accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO) or a dispersed oil (DO) mixture of PBCO and Corexit 9527 spiked with [U-14C]naphthalene. Uptake was determined by the amount of algae-associated [14C]. High-pressure liquid chromatography (HPLC) co-chromatography was used to fractionate and identify metabolic products. A 24-h bioaccumulation factor (BAF) was calculated in the absence of steady state. The presence of Corexit 9527, had significant influence (p = 0.001) on the uptake of naphthalene, but no significant effect on the 24-h BAF (BAF: 168 and 180 from WAF and DO, respectively), or metabolic fate of naphthalene in I. galbana. Results of this research indicate that dispersants have the potential to increase organismal exposure to certain petroleum hydrocarbons without increasing their aqueous concentration.
In VivoChlorophyll A Fluorescence of Selenastrum capricornutum as a Screening Bioassay in Toxicity Studies by J. A. van der Heever; J. U. Grobbelaar (pp. 281-286).
A method for the estimation of the effect of specific toxins on phytoplankton photosynthesis (index of toxicity) was investigated using in vivo chlorophyll a fluorescence. No meaningful results were obtained with the following substances; copper, cadmium, mercury, and gusathion, within a 4-h exposure period. It can, therefore, be concluded that in vivo chlorophyll a fluorescence are not a simple bioassay tool, due to the complexity of its origins, but a complex research tool.
Honey Bees as Indicators of Radionuclide Contamination: Comparative Studies of Contaminant Levels in Forager and Nurse Bees and in the Flowers of Three Plant Species by T. K. Haarmann (pp. 287-294).
Two separate field experiments were conducted as part of ongoing research concerning the use of honey bees (Apis mellifera) as indicators of environmental radionuclide contamination. The experiments were conducted in a study site containing radionuclide contamination above background levels. The first experiment compared levels of radionuclides found in forager bees to levels found in nurse bees. Bees were collected from colonies, analyzed for concentrations of radionuclides, and the results were compared using statistical methods. Results indicated that there is no significant difference between the contaminant levels in forager and nurse bees. A second experiment compared the levels of radionuclides found in the flowers of three plant species growing in the study site: salt cedar (Tamarix ramosissima), white sweet clover (Melilotus albus), and rabbit brush (Chrysothamnus nauseosus). Results indicated that there is no significant difference in the amounts of radionuclides found in the flowers of these three plants.
Effects of Temperature and Exposure Duration on Transfer of Cadmium Between Naturally Contaminated Sediments and Burrowing Mayfly Nymphs (Hexagenia rigida) by S. Andres; F. Ribeyre; A. Boudou (pp. 295-301).
Burrowing mayfly nymphs (Hexagenia rigida) were exposed to naturally contaminated sediments collected from two stations along a metallic pollution gradient on the Lot River (France) using indoor microcosms. Bioaccumulation kinetics (0, 20, 40, and 60 days) of cadmium (Cd) and the combined effects of temperature (12, 18, and 24°C) were evaluated by a complete experimental design, jointly with the analysis of growth rate of the nymphs, bioturbation, and total and dissolved Cd concentrations in the water column. Cadmium was transferred from the sediment to the organisms with uptake influenced by contamination levels of the sediments, exposure duration, and temperature. The two complementary criteria—Cd concentration and burden in the nymphs—clearly demonstrate the importance of the growth dilution on the quantification of Cd bioaccumulation at the whole organism level.
Pollution-Tolerant Allele in Fingernail Clams (Musculium transversum) by B. L. Sloss; M. A. Romano; R. V. Anderson (pp. 302-308).
For nearly 50 years, the fingernail clam (Musculium transversum) was believed to be virtually eliminated from the Illinois River. In 1991, workers began finding substantial populations of M. transversum in the Illinois River including several beds in and around the highly polluted Chicago Sanitary District. In order to determine if populations of M. transversum from polluted sites exhibited any genetic response to the high levels of toxins and to examine the genetic structure of several populations of M. transversum for any changes due to the population crash, starch-gel electrophoresis was performed on M. transversum from three Illinois River localities and four Mississippi River basin locations. The sampled populations produced an inbreeding coefficient (FIS) of 0.929, indicating that the populations were highly inbred. The results of a suspected founder effect due to a bottleneck was suggested by an FST= 0.442. The isozyme Glucose-6-phosphate isomerase-2 (Gpi-2) produced allelic frequency patterns that were consistent with expected patterns of a pollution-tolerant allele. Polluted sites exhibited elevated frequencies of Gpi-2 100 whereas nonpolluted sites exhibited elevated frequencies of Gpi-2 74 . This frequency pattern suggested that natural selection was occurring in populations under severe toxic pressures, leading to an increase in the frequency of the allele Gpi-2 100 . Therefore, Gpi-2 100 is a possible pollution-tolerant mutation in M. transversum.
Whole Effluent Toxicity Testing with Oncorhynchus mykiss (Walbaum 1792): Survival and Behavioral Responses to a Dilution Series of a Mining Effluent in South Africa by A. Gerhardt (pp. 309-316).
Survival, behavioral early warning responses to, and behavioral effects of a complex effluent from Richards Bay Minerals in Natal, South Africa, were studied using rainbow trout Oncorhynchus mykiss (Walbaum 1792) as a biosensor. Three replicates of eight juvenile fish were exposed to a dilution series of the effluent (0, 5, 10, 20, 50, 75, 100%) and the behavioral pattern (ventilation, locomotion) was measured online with quadropole impedance conversion. Survival decreased with increasing effluent concentration. Before death, O. mykiss coloration darkened, demonstrating skewed bodies subsequently after death. Decreased activity and increased ventilation combined with increased ventilation frequency were found within the first 2 h of exposure at ≥96-h LC50 value of 10% effluent concentration indicating early warning responses. During 4 days of exposure, activity decreased and ventilation increased further at concentrations around the 96-h LC50 value indicating toxic effects.
Toxicity and Pathogenicity Testing of the Insect Pest Control Fungus Metarhizium anisopliae by F. J. Genthner; C. A. Chancy; J. A. Couch; S. S. Foss; D. P. Middaugh; S. E. George; M. A. Warren; J. A. Bantle (pp. 317-324).
Renewed interest in the use of Metarhizium anisopliae and its toxins for insect control prompted the following safety assessment. A neutral extract (methylene chloride, pH 7.2), derived from M. anisopliae cultures, was evaluated for toxicity and mutagenicity using aquatic animal bioassays and the Ames test. The average LC50 of the neutral extract obtained in static, acute 96-h tests conducted with ≤24-h-old Mysidopsis bahia was 2.41 mg L−1. By partially purifying destruxins from the neutral extract, it was shown that destruxins alone were not responsible for the observed toxicity in mysids. The neutral extract was fetotoxic to developing grass shrimp, Palaemonetes pugio, and frog, Xenopus laevis, embryos; the LC50 values were 52 and 32 mg L−1, respectively. Eye spot abnormalities were observed in shrimp and frog embryos exposed to the neutral extract. In extract-exposed frog embryos, moderate to severe cranial, facial, and gut malformations were also observed. The neutral extract was toxic to juvenile mosquito fish, Gambusia affinis, at an LC50 value of 141 mg L−1. Adult female G. affinis surviving a 24-h exposure to 200 μg ml−1 of the neutral extract produced healthy broods. After 3 months, no mortalities or adverse effects were observed in adult G. affinis fed a diet partially composed of a freeze-dried M. anisopliae culture. The neutral extract did not show mutagenicity in the Ames test using strains TA98 and TA100 with and without metabolic activation by rat liver S9. Significant (p ≤ 0.05) mortalities were obtained when embryos of grass shrimp and inland silverside fish, Menidia beryllina, were exposed to the same lot of M. anisopliae conidiospores. Exposure of frog embryos to M. anisopliae conidiospores did not cause significant (p > 0.05) mortalities or malformations.
Elevated Trace Element Concentrations in Southern Toads, Bufo terrestris, Exposed to Coal Combustion Waste by W. A. Hopkins; M. T. Mendonça; C. L. Rowe; J. D. Congdon (pp. 325-329).
A number of recent studies have linked developmental, physiological, and behavioral abnormalities in amphibians to coal combustion wastes (coal ash). Few studies, however, have determined trace element concentrations in amphibians exposed to coal ash. In the current study we compare total body concentrations of 20 trace elements in adult southern toads, Bufo terrestris, inhabiting coal ash settling basins with toads that were not exposed to the combustion wastes (reference). In addition, we document the accumulation of trace elements in toads transplanted from reference sites to field enclosures in an ash settling basin for 7 and 12 weeks. Arsenic, selenium, and vanadium levels were significantly elevated in toads captured at the ash-contaminated site in comparison to toads from the reference site. All three of these elements were also significantly elevated in toads exposed to the contaminated habitat for only 7 weeks. Our study suggests that adult anurans can bioaccumulate particularly high levels of selenium and may be useful bioindicators in agricultural and coal ash-impacted habitats.
Mercury Accumulation and Biomagnification in Ospreys (Pandion haliaetus) in the James Bay and Hudson Bay Regions of Québec by J.-L. DesGranges; J. Rodrigue; B. Tardif; M. Laperle (pp. 330-341).
Mercury exposure was examined in adults and nestlings of ospreys (Pandion haliaetus) from lakes, rivers, and hydroelectric reservoirs in northern Québec between 1989 and 1991 by assessing the amount of mercury transferred from fish to ospreys, which are voracious fish-eaters. The high mercury concentrations detected in adult feathers and tissues (feathers, blood, liver, kidneys, muscles, brain) of nestlings indicate an increase in mercury availability at recently constructed hydroelectric reservoirs (10–12 years for the La Grande-2 Reservoir). With mean total mercury levels of 37.3 mg/kg and 1.9 mg/kg in feathers (dry weight) and in blood (wet weight), respectively, contamination rates were, in both tissues, five times higher for chicks born near the La Grande Reservoirs (western sector) than in those reared in natural habitats. Furthermore, the mean quantity of total mercury in 40-day-old chicks reared near a reservoir was 10.5 mg, compared with to 1.6 mg for those reared in a natural environment. Modeling of mercury transfer from fish to osprey nestlings showed that the mercury level in chicks' blood provides a good estimate of mercury concentrations in ingested food. In addition, the relationship between mercury concentrations in the blood and that in feathers indicates that substantial biomagnification of mercury occurs from the ingested dose to the feathers. The intensity of this biomagnification varies with the age of the chicks and reaches a maximum value as the flight feathers start to form (at 20–25 days of age) declining thereafter until the bird is 45 days old and growth of those feathers is complete.Nevertheless, the mean number of young fledged on reservoirs where mercury exposure is greatest (>40 mg/kg of Hg in chicks' feathers) did not differ (1.6 ± 0.7) from that observed elsewhere in built-up environments (1.9 ± 0.7) or in natural habitats (2.0 ± 0.7) (H = 4.39; p = 0.11). Storage of mercury in growing feathers (86% of all mercury in osprey) prevents accumulation in living tissues, thereby protecting the chick from related toxic effects. However, toxicological problems may arise after fledging. In particular, attention should be paid to postfledging survival before concluding that mercury exposure is insufficiently high in Osprey young reared at reservoirs.
High Prevalences of Lead Poisoning in Wintering Waterfowl in Spain by R. Mateo; J. Belliure; J. C. Dolz; J. M. Aguilar Serrano; R. Guitart (pp. 342-347).
Some Mediterranean wetlands are found between the areas with the highest prevalence of lead pellet exposure for waterfowl in the world. To assess the situation in Spain, availability of pellets in sediments and rates of ingestion by waterfowl were determined in four important wetlands: Albufera de València, El Fondo, Tablas de Daimiel, and Doñana (Guadalquivir Marshes). Lead pellet density in sediment was maximum in the Albufera, with 2.8 million pellets/ha. In Tablas de Daimiel, where hunting was banned in 1965, about 1.0 million pellets/ha were found. Percentages of shot waterfowl with ingested pellets were maximum in the wetlands on the Mediterranean coast (El Fondo and Albufera de València): 87.5% of common pochard (Aythya ferina) and approximately 33% of mallard (Anas platyrhynchos) and shoveler (Anas clypeata) contained ingested pellets. It was found that mallards with > 5 μg/g dry weight of lead in the liver had 8.5% lower body condition and 7.7% less body weight than birds with lower lead concentrations. Moreover, lead poisoning was diagnosed as the cause of death in 16 out of 75 birds, mainly greylag geese (Anser anser), found dead in some of these zones.
Effects of Dietary Exposure to 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Adult Female Mink (Mustela vison) by J. R. Hochstein; S. J. Bursian; R. J. Aulerich (pp. 348-353).
Adult female mink were fed diets supplemented with 0, 0.001, 0.01, 0.1, 1, 10, or 100 ppb 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for up to 125 days. There was a dose-dependent decrease in feed consumption and body weights indicative of the “wasting syndrome” previously reported for mink and other species exposed to chlorinated hydrocarbon compounds. Mortality reached 12.5, 62.5, and 100% by day 28 in the 1-, 10-, and 100-ppb groups, respectively, and by day 125, mortality increased to 62.5 and 100% in the 1- and 10-ppb groups, respectively. Adrenal gland weights were significantly greater in the three highest dose groups compared to the control group. The percentage of band neutrophils was also significantly greater in the TCDD-treated groups compared to the control. LC50 (±SE) values for 28 and 125 days of dietary exposure to TCDD were calculated to be 4.8 ± 4.99 ppb and 0.85 ± 0.64 ppb, respectively. Based on feed consumption of control mink, these LC50 concentrations approximate 0.264 and 0.047 μg TCDD/kg body weight/day for the 28- and 125-day exposure periods, respectively. These results confirm the sensitivity of mink to TCDD.
Chlorinated Hydrocarbon Contaminants in Polar Bears from Eastern Russia, North America, Greenland, and Svalbard: Biomonitoring of Arctic Pollution by R. J. Norstrom; S. E. Belikov; E. W. Born; G. W. Garner; B. Malone; S. Olpinski; M. A. Ramsay; S. Schliebe; I. Stirling; M. S. Stishov; M. K. Taylor; Ø. Wiig (pp. 354-367).
Adipose tissue samples from polar bears (Ursus maritimus) were obtained by necropsy or biopsy between the spring of 1989 to the spring of 1993 from Wrangel Island in Russia, most of the range of the bear in North America, eastern Greenland, and Svalbard. Samples were divided into 16 regions corresponding as much as possible to known stocks or management zones. Concentrations of dieldrin (DIEL), 4,4′-DDE (DDE), sum of 16 polychlorinated biphenyl congeners (ΣPCB), and sum of 11 chlordane-related compounds and metabolites (ΣCHL) were determined. In order to minimize the effect of age, only data for adults (320 bears age 5 years and older) was used to compare concentrations among regions. Concentrations of ΣPCB were 46% higher in adult males than females, and there was no significant trend with age. Concentrations of ΣCHL were 30% lower in adult males than females. Concentrations of ΣPCB, ΣCHL, and DDE in individual adult female bears were standardized to adult males using factors derived from the least-square means of each sex category, and geometric means of the standardized concentrations on a lipid weight basis were compared among regions. Median geometric mean standardized concentrations (lipid weight basis) and ranges among regions were as follows: ΣPCB, 5,942 (2,763–24,316) μg/kg; ΣCHL, 1,952 (727–4,632) μg/kg; DDE, 219 (52–560) μg/kg; DIEL, 157 (31–335) μg/kg. Geometric mean ΣPCB concentrations in bears from Svalbard, East Greenland, and the Arctic Ocean near Prince Patrick Island in Canada were similar (20,256–24,316 μg/kg) and significantly higher than most other areas. Atmospheric, oceanic, and ice transport, as well as ecological factors may contribute to these high concentrations of ΣPCB. ΣCHL was more uniformly distributed among regions than the other CHCs. Highest ΣCHL concentrations were found in southeastern Hudson Bay, which also had the highest DDE and DIEL concentrations. In general, concentrations of ΣCHL, DDE, and DIEL were higher in eastern than western regions, suggesting an influence of North American sources. Average ΣPCB concentrations in bears from the Canadian Arctic were similar to those in 1982–84, while average ΣCHL and DDE concentrations were 35–44% lower and DIEL was 90% lower. However, the significance of these temporal trends during the 1980s is not conclusive because of the problems of comparability of data.