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Archives of Environmental Contamination and Toxicology (v.39, #4)

The Cell Wall as a Barrier to Uptake of Metal Ions in the Unicellular Green Alga Chlamydomonas reinhardtii (Chlorophyceae) by S. M. Macfie; P. M. Welbourn (pp. 413-419).

The cell walls of plants, including those of algae, have the capacity to bind metal ions in negatively charged sites. The authors had already shown that the wild type (walled) strain of the unicellular green alga Chlamydomonas reinhardtii Dangeard was more tolerant to Cd, Co, Cu, and Ni than a wall-less mutant of the same species. The objective of the present study was to determine if the tolerance to metals was associated with an increased adsorption of the same metals to the cell wall. Adsorbed metal was defined as that fraction that could be removed with a solution containing Na₂EDTA and CaCl₂. The fraction that remained after the EDTA/CaCl₂ wash was considered to be strongly bound in the cell. When exposed to metals, singly, in solution for 24 h, cells of both strains accumulated the metals. The original hypothesis was supported by the results for Cd, Co, and Ni insofar as significantly higher concentrations of these metals were in the loosely bound fraction of the walled strain in comparison with the wall-less strain. However, there are three reasons why the potentially protective effect of the cell wall did not explain differential tolerance of the two strains. After 24 h of exposure (1) less Cd was accumulated internally by the wall-less strain than by the walled strain, (2) very little of the accumulated Cu was in the loosely bound fraction of the walled strain, and (3) the two strains accumulated comparable and relatively high amounts of internal Cu. Unexpectedly, significant amounts of Cd and Cu were also removable from the surface of the wall-less cells. One possible explanation for these apparently externally bound metals in the wall-less strain is that the cells exuded metal-chelating molecules that decreased the ability of metal ions to penetrate the plasma membrane. It was concluded that metal tolerance in this alga must involve a complex of mechanisms involving both internal and external detoxification of metal ions.

Quantification of Metal Bioavailability for Lettuce (Lactuca sativa L.) in Field Soils by W. Peijnenburg; R. Baerselman; A. de Groot; T. Jager; D. Leenders; L. Posthuma; R. Van Veen (pp. 420-430).

Understanding metal bioavailability of plants in soils requires, apart from physiological processes and symbiosis with arbuscular mycorrhizal fungi, the consideration of the chemical availability in the soil solution (the intensity of the toxic exposure) and the soil's capacity to supply the metal (capacity). In this contribution we report on the time-dependent accumulation of As, Cd, Cr, Cu, Ni, Pb, and Zn in lettuce (Lactuca sativa L.). Bioassays with 17 Dutch field soils and two artificially metal-contaminated soils were carried out. Phytotoxicity was observed in soils with pH (pore water) <4.8. Metal uptake is shown to be both metal- and soil-dependent and strongly depends on the amount of water the plant transpired and the available concentration in the water. No net accumulation of As, Pb, Ni, and especially Cr was observed in most soils tested. The latter observation is in agreement with findings of Zayed et al. (Planta, 1998 206:293–299), who reported that translocation of Cr from roots to shoots is extremely limited. Internal Cd levels in the plants varied greatly among soils, whereas plant tissue concentrations of Zn and especially Cu appear to be regulated at more or less fixed levels. The 0.01 M CaCl₂-extractable metal pool provides the best descriptor for the capacity of the soil to supply Cd and Zn. This enabled the development of models that are suited to predict Zn and Cd uptake by lettuce in both field soils (weathered soils) and soils to which metal salts were added, which is common practice in toxicity testing of chemicals. It is concluded that of all metals included in this study, Cd is the metal of most concern due to bioaccumulation through the soil-plant-animal food chain as Cd is the only metal that might pose human or animal health risks at plant tissue concentrations that are not directly phytotoxic. Finally, application of the models for risk assessment purposes is discussed.

Toxicity and Bioaccumulation of Copper to Black Bindweed (Fallopia convolvulus) in Relation to Bioavailability and the Age of Soil Contamination by M. Bruus Pedersen; C. Kjær; N. Elmegaard (pp. 431-439).

The use of ecotoxicity test results obtained in the laboratory for prediction of effects of potentially toxic concentrations of chemicals in the field is hampered by several factors differing between the laboratory and the field situations. One important factor is the binding of test chemicals to soil, which is affected by the age of the contamination and soil type. The present study investigated the effect of contamination age by introducing an aging period of 1 to 12 weeks between mixing the test substance, copper sulfate, in with soil and introducing the test plant, Fallopia convolvulus (L.) A. Löve. Copper accumulation, emergence of cotyledons, and growth were assessed and related to total (boiling with HNO₃) and 0.01 M CaCl₂- and DTPA-extractable soil copper concentrations. Aging of the copper-contaminated soil had only small effects on bioaccumulation of copper, copper toxicity, and extractable soil copper fractions. Soil copper had no effect on emergence of cotyledons. Estimated EC₅₀ values for shoot and root growth averaged 280 mg Cu/kg. Effects on growth in these laboratory-treated soils were much more severe than in a study performed in soil from an old copper-contaminated field site. Neither CaCl₂- nor DTPA-extractable copper fractions could explain all of the differences in effects between aged spiked soil and field soil.The accumulation pattern for roots and shoots of F. convolvulus indicated that excessive copper was accumulated and adsorbed mainly by the fine roots, whereby the copper concentrations of other plant parts were kept low until the plant was no longer able to maintain this regulation. An internal threshold for effects on growth of about 20 mg Cu/kg shoot dry weight was estimated, coinciding with a soil copper concentration of approximately 200 mg/kg.

Assessment of Barium Toxicity in Bush Beans by M. Llugany; C. Poschenrieder; J. Barceló (pp. 440-444).

External and internal lowest observed effect concentrations (LOECs) for Ba in bean plants (Phaseolus vulgaris) were established using a nutrient solution culture system where BaSO₄ precipitation in the growth medium was avoided. This was achieved by alternating every 24 h with a nutrient solution containing Ba (0, 50, 500, or 5000 μM) and all essential elements except S, with another containing S and all other nutrients but no Ba. The external LOEC for acute toxicity symptoms in the form of leaf withering and leaf growth inhibition was 481 μM of free Ba²⁺. This was also the LOEC for the complete inhibition of elongation of secondary roots, while for the elongation of the primary root the external LOEC was 4,821 μM. Barium interfered with both the sulfate transport from roots to shoots and the import of Ca into leaves. However, K was the most Ba-sensitive nutrient. External LOEC for reduced leaf K concentrations was 48 μM free Ba²⁺; the corresponding internal LOECs for primary and trifoliolate leaves were 700 and 460 mg kg⁻¹ DW, respectively.

Toxicity and Bioavailability of Copper Herbicides (Clearigate, Cutrine-Plus, and Copper Sulfate) to Freshwater Animals by B. J. Mastin; J. H. Rodgers, Jr. (pp. 445-451).

In designing aquatic herbicides containing copper, an important goal is to maximize efficacy for target species while minimizing risks for nontarget species. To have a margin of safety for nontarget species, the concentration, duration of exposure (i.e., uptake), and form (i.e., species) of copper used for herbicidal properties should not elicit adverse effects on populations of nontarget species. To determine the potential for risk or adverse effects (conversely the margin of safety), data regarding the comparative toxicity of copper-containing herbicides are crucial. A series of comparative toxicity experiments was conducted, including baseline estimates of toxicity (LC50s, LOECs), sensitive species relationships (thresholds and exposure-response slopes), and bioavailability of toxic concentrations and forms of copper 7 days after initial herbicide application. Aqueous 48-h toxicity experiments were performed to contrast responses of Daphnia magna Strauss, Hyalella azteca Saussure, Chironomus tentans Fabricius, and Pimephales promelas Rafinesque to copper herbicides: Clearigate®, Cutrine®-Plus, and copper sulfate. D. magna was the most sensitive aquatic animal tested for all three herbicides; 48-h LC50s for organisms exposed to Clearigate, Cutrine-Plus, and copper sulfate were 29.4, 11.3, and 18.9 μg Cu/L, respectively. In terms of potency (calculated from the linearized portion of the exposure-response curves, which included 50% mortality), D. magna was the most sensitive animal tested. Organisms exposed to Clearigate, Cutrine-Plus, and copper sulfate had exposure-response slopes of 2.55, 8.61, and 5.07% mortality/μg Cu/L, respectively. Bioavailability of Clearigate and Cutrine-Plus was determined by comparing survival data (LC50s) of test organisms exposed to herbicide concentrations during the first and last 48-h of a 7-day exposure period. Even in these relatively simplified water-only exposures, a transformation of copper to less bioavailable species over time was observed with a 100–200% decrease in toxicity (i.e., an increase in 48-h LC50s) for all four test animals. This series of laboratory experiments provides a worst-case scenario for determining the risk associated with the manufacturer's recommended application rates of Clearigate (100–1,000 μg Cu/L), Cutrine-Plus (200–1,000 μg Cu/L), and copper sulfate (100–500 μg Cu/L) in natural waters for four nontarget freshwater animals.

An Evaluation of the Toxicity of Contaminated Sediments from Waukegan Harbor, Illinois, Following Remediation by N. E. Kemble; D. G. Hardesty; C. G. Ingersoll; B. T. Johnson; F. J. Dwyer; D. D. MacDonald (pp. 452-461).

Waukegan Harbor in Illinois was designated as a Great Lakes Area of Concern due to high concentrations of sediment-associated polychlorinated biphenyls (PCBs). The objective of this study was to evaluate the toxicity of 20 sediment samples collected after remediation (primarily dredging) of Waukegan Harbor for PCBs. A 42-day whole sediment toxicity test with the amphipod Hyalella azteca (28-day sediment exposure followed by a 14-day reproductive phase) and sediment toxicity tests with Microtox® were conducted to evaluate sediments from Waukegan Harbor. Endpoints measured were survival, growth, and reproduction (amphipods) and luminescent light emission (bacteria). Survival of amphipods was significantly reduced in 6 of the 20 sediment samples relative to the control. Growth of amphipods (either length or weight) was significantly reduced relative to the control in all samples. However, reproduction of amphipods identified only two samples as toxic relative to the control. The Microtox basic test, conducted with organic extracts of sediments identified only one site as toxic. In contrast, the Microtox solid-phase test identified about 50% of the samples as toxic. A significant negative correlation was observed between reproduction and the concentration of three polynuclear aromatic hydrocarbons (PAHs) normalized to total organic carbon. Sediment chemistry and toxicity data were evaluated using sediment quality guidelines (consensus-based probable effect concentrations, PECs). Results of these analyses indicate that sediment samples from Waukegan Harbor were toxic to H. azteca contaminated at similar contaminant concentrations as sediment samples that were toxic to H. azteca from other areas of the United States. The relationship between PECs and the observed toxicity was not as strong for the Microtox test. The results of this study indicate that the first phase of sediment remediation in Waukegan Harbor successfully lowered concentrations of PCBs at the site. Though the sediments were generally not lethal, there were still sublethal effects of contaminants in sediments at this site observed on amphipods in long-term exposures (associated with elevated concentrations of metals, PCBs, and PAHs).

Sediment Toxicity Assessment: Comparison of Standard and New Testing Designs by K. T. Ho; A. Kuhn; M. Pelletier; F. McGee; R. M. Burgess; J. Serbst (pp. 462-468).

Standard methods of sediment toxicity testing are fairly well accepted; however, as with all else, evolution of these methods is inevitable. We compared a standard ASTM 10-day amphipod toxicity testing method with smaller, 48- and 96-h test methods using very toxic and reference sediments. In addition we compared parallel exposures of single species, either the amphipod Ampelisca abdita or the mysid Americamysis bahia, to multiple species, mysid, and amphipod, cohabiting the same types of chambers. These comparisons were performed for both water-only and sediment-water tests. Results of the comparison of the standard ASTM 10-day amphipod test with the smaller, 48- and 96-h test chambers indicate that survival was high in both test designs using the reference sediment. With toxic sediments, complete mortality occurred in less than 48 h using the smaller experimental chambers and only after 96 h in the larger experimental chambers. We concluded that although time to death is shorter in the smaller, shorter exposure chambers, there was no overall change in mortality for the organisms, and that the smaller chambers were predictive of the results obtained with larger chambers and longer exposures. For multiple species testing in whole sediment exposures there was no change in toxicity to either the amphipod or the mysid when they cohabited the same chamber. In contrast, for water-only exposures, A. bahia demonstrated less sensitivity when cohabiting the same chamber as A. abdita. Therefore, during whole sediment testing we can add A. bahia and A. abdita to the same test chamber without changing the toxicity to either species; however, in our 10-ml water-only exposures, the species should be tested separately.

A Comparison of Selected Diversity, Similarity, and Biotic Indices for Detecting Changes in Benthic-Invertebrate Community Structure and Stream Quality by M. J. Lydy; C. G. Crawford; J. W. Frey (pp. 469-479).

Implementation of advanced wastewater treatment at the two municipal wastewater-treatment plants for Indianapolis, Indiana, resulted in substantial improvement in the quality of the receiving stream and significant changes in the benthic-invertebrate community. Diversity, similarity, and biotic indices were compared to determine which indices best reflected changes in the composition of the biota in the river. None of the indices perfectly reflected the changes in river quality or community structure. Similarity indices, especially percentage similarity, exhibit the most promise of the three classes of indices. Diversity indices were least useful, wrongly indicating that water quality deteriorated after the upgrade of the wastewater-treatment plants. The most descriptive tool in analyzing the data was the percentage of Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa present. Using a mixture of indices and other analytical tools, such as EPT, in the analysis of biological data will ensure the most effective investigations of water quality.

Hemocytic Lysosome Response in the Snail Helix aspersa After Exposure to the Fungicide Copper Oxychloride by R. G. Snyman; S. A. Reinecke; A. J. Reinecke (pp. 480-485).

This study investigated the use of lysosomal responses of hemocytes of the common garden snail, Helix aspersa, as biomarker of stress due to exposure to the fungicide copper oxychloride. The neutral red retention (NRR) time assay was employed for this purpose. Two groups of snails were exposed to 80 μg g⁻¹ and 240 μg g⁻¹ copper oxychloride in their food, respectively, for a period of 6 weeks. They were compared with a control group to which no copper oxychloride was added. The two groups exposed to the fungicide exhibited significantly higher (p < 0.001) whole body copper concentrations (200.85 ± 53.5 and 272.24 ± 67.15 μg g⁻¹ dry mass, respectively), and significantly shorter (p < 0.001) NRR times (10.22 ± 3.53 and 2.67 ± 2.83 min, respectively), after 6 weeks, compared to the control group (67.85 ± 31.08 μg g⁻¹ dry mass and 24.44 ± 8.35 min). In both exposure groups NRR times became progressively shorter as body copper concentrations increased over time. Thus, both exposure concentration and exposure time of copper oxychloride were shown to be important factors influencing lysosomal responses (and therefore NRR times) of H. aspersa hemocytes. It was concluded that these responses in this species, as measured by the NRR time assay, could be considered a useful cellular biomarker of stress resulting from exposure to copper oxychloride.

Effect of Single and Binary Combinations of Plant-Derived Molluscicides on Reproduction and Survival of the Snail Achatina fulica by I. G. Rao; D. K. Singh (pp. 486-493).

The effects of sublethal treatments (20% and 60% of LC₅₀/24 h) with plant-derived molluscicides on the reproduction of the giant African snail Achatina fulica were studied. Azadirachta indica oil, Cedrus deodara oil, Allium sativum bulb powder, and Nerium indicum bark powder singly and binary combinations on reproduction and survival of A. fulica were investigated. Repeated treatment occurred on day 0, day 15, and day 30. These plant-derived molluscicides significantly reduced fecundity, egg viability, and survival of A. fulica within 15 days. Discontinuation of the treatments after day 30 did not lead to a recovery trend in the next 30 days. Day 0 sublethal treatment of all the molluscicides caused a maximum reduction in protein, amino acid, DNA, RNA, and phospholipid levels and simultaneous increase in lipid peroxidation in the ovotestis of treated A. fulica. It is believed that sublethal exposure of these molluscicides on snail reproduction is a complex process, involving more than one factor in reducing the reproductive capacity of A. fulica.

Combined Effects of UV-B, Nitrate, and Low pH Reduce the Survival and Activity Level of Larval Cascades Frogs (Rana cascadae) by A. C. Hatch; A. R. Blaustein (pp. 494-499).

We investigated interactions between low pH, high nitrate level, and ultraviolet-B (UV-B) light on the survival and activity level of larval Cascades frogs (Rana cascadae). We used a fully factorial experimental design, with pH levels of 5 and 7; initial “pulse” nitrate exposure levels of 0, 5, and 20 mg/L; and UV-B present or absent. After a 3-week laboratory exposure, we measured survival and activity level of the larvae. The experiment was repeated two times, in two separate years. Similar effects on survival and activity level were observed in both experiments. R. cascadae survival was not significantly reduced in treatments with individual factors alone (i.e., UV-B control, pH 5 control, or high nitrate level without pH or UV-B). However, in experiments from both years, survival and activity levels of larval R. cascadae were significantly reduced in the treatment with low pH, high nitrate, and UV-B together. In both years, analysis of variance (ANOVA) indicated that pH and nitrate had the greatest effect on survival and that UV-B and nitrate had the greatest effect on activity level. Additional effects were observed in the 1998 experiment on both survival and activity level. In 1998, UV radiation and the interaction term between pH and nitrate (pH × nitrate) had a significant effect on survival. Also in the 1998 experiment, activity level was significantly reduced in treatments at neutral pH with UV, at initial nitrate doses of 5 and 20 mg/L and at neutral pH without UV at an initial nitrate dose of 20 mg/L. We suggest that the adverse effects were due to the multiple stressors acting together.

Chlorinated Hydrocarbon Concentrations in Plasma of the Lake Erie Water Snake (Nerodia sipedon insularum) and Northern Water Snake (Nerodia sipedon sipedon) from the Great Lakes Basin in 1998 by C. A. Bishop; J. D. Rouse (pp. 500-505).

From the Great Lakes basin, concentrations of 59 congener-specific polychlorinated biphenyls (PCBs) and 14 organochlorine pesticides were measured in blood plasma of northern water snake (Nerodia sipedon sipedon) and Lake Erie water snake (Nerodia sipedon insularum), which is endangered in Canada. In 1998, four male adult Lake Erie water snakes were sampled from Pelee Island, western Lake Erie; four male northern water snakes were sampled at Little Lake, about 20 km north of Parry Sound in central Ontario; and four adult gravid female northern water snakes were sampled from Garden Island, eastern Lake Ontario. The blood plasma was pooled by site for a total of three samples analyzed.The Pelee Island sample from male Lake Erie water snakes contained less than half the lipid concentration (0.349%) than samples from the other sites, but it was the most contaminated with PCBs, even on a wet weight basis. Summed concentration of individual PCBs in the Pelee Island sample was 167 ng/g (wet weight), which was 14-fold higher than the next most contaminated sample, which was from Little Lake. The plasma sample from Little Lake contained 12 ng/g (WW) and was four times more contaminated with PCBs than the sample from female snakes from Garden Island, Lake Ontario. Organochlorine pesticide concentrations in plasma were relatively similar among sites. None of the pesticides was found above trace concentrations (0.1–0.9 ng/g) except pp′-DDE, which occurred at 2–5 ng/g among sites.PCB congener patterns in the Lake Erie water snakes were compared to PCB patterns in plasma of common snapping turtle (Chelydra serpentina serpentina) from Lake Ontario, herring gull eggs (Larus argentatus) from western Lake Erie, and mudpuppy eggs (Necturus maculosus) from the Detroit River. The PCB patterns in water snake and herring gull sample were most similar, followed by the pattern in snapping turtle plasma. The presence of more lower-chlorinated chlorobiphenyls in the mudpuppy eggs relative to the other species made this sample distinct from the water snake, gull, and turtle.

Reclamation of Wastewater for Polyculture of Freshwater Fish: Bioassays Using Chlorella and Gambusia by Y. Liang; M. H. Wong (pp. 506-514).

The feasibility of using the secondary effluents from two sewage treatment plants in Hong Kong (Yuen Long and Shek Wu Hui) for fish culture was assessed. Total ammonia contents in the two sewage effluents surpassed the level of 2 mg L⁻¹ recommended for wastewater fish culture. The two sewage effluents both needed essential elements for supporting algal Chlorella vulgaris growth, whereas only sewage effluent from Yuen Long had contaminants at toxic levels. Total ammonia in water explained more than 80% variations of toxicity of water samples to Gambusia patruelis, mosquito fish, according to regression analysis. Removal of ammonia from the sewage effluent is necessary before being used for fish culture. In addition, the rather high levels of heavy metals (Cu, Zn, Cd) in the effluent should be closely monitored.

Metal Analysis of Scales Taken from Arctic Grayling by A. P. Farrell; A. H. Hodaly; S. Wang (pp. 515-522).

This study examined concentrations of metals in fish scales taken from Arctic grayling using laser ablation–inductively coupled plasma mass spectrometry (LA-ICPMS). The purpose was to assess whether scale metal concentrations reflected whole muscle metal concentrations and whether the spatial distribution of metals within an individual scale varied among the growth annuli of the scales. Ten elements (Mg, Ca, Ni, Zn, As, Se, Cd, Sb, Hg, and Pb) were measured in 10 to 16 ablation sites (5 μm radius) on each scale sample from Arctic grayling (Thymallus arcticus) (n = 10 fish). Ca, Mg, and Zn were at physiological levels in all scale samples. Se, Hg, and As were also detected in all scale samples. Only Cd was below detection limits of the LA-ICPMS for all samples, but some of the samples were below detection limits for Sb, Pb, and Ni. The mean scale concentrations for Se, Hg, and Pb were not significantly different from the muscle concentrations and individual fish values were within fourfold of each other. Cd was not detected in either muscle or scale tissue, whereas Sb was detected at low levels in some scale samples but not in any of the muscle samples. Similarly, As was detected in all scale samples but not in muscle, and Ni was detected almost all scale samples but only in one of the muscle samples. Therefore, there were good qualitative and quantitative agreements between the metal concentrations in scale and muscle tissues, with LA-ICPMS analysis of scales appearing to be a more sensitive method of detecting the body burden of Ni and As when compared with muscle tissue. Correlation analyses, performed for Pb, Hg, and Se concentrations, revealed that the scale concentrations for these three metals generally exceeded those of the muscle at low muscle concentrations. The LA-ICPMS analysis of scales had the capability to resolve significant spatial differences in metal concentrations within a fish scale. We conclude that metal analysis of fish scales using LA-ICPMS shows considerable promise as a nonlethal analytical tool to assess metal body burden in fish that could possibly generate a historic record of metal exposure. However, comprehensive validation experiments are still needed.

Development of an Index of Biotic Integrity for the Little Arkansas RiverBasin, Kansas by M. J. Lydy; A. J. Strong; T. P. Simon (pp. 523-530).

An index of biotic integrity (IBI) was developed for the Little Arkansas River Basin (LARB) in south-central Kansas by establishing a reference condition for the watershed. Twelve metrics, in six categories, were chosen for use in the IBI. Fish assemblages from 30 sites were selected to represent the highest quality sites (reference sites) remaining in the LARB. In addition, 20 historical sites were used to show changes in the watershed over the last century. The modified IBI was then tested at 10 sites within the basin to assess the affects of urban and agricultural disturbances on fish community structure in the Wichita area. IBI scores were statistically lower for the urban versus the agricultural sites. Overall, IBI scores rated from poor to fair, supporting the contention that the fish communities within the LARB are impaired.

Assessment of Water Quality in Wichita, Kansas, Using an Index of Biotic Integrity and Analysis of Bed Sediment and Fish Tissue forOrganochlorine Insecticides by H. J. Eaton; M. J. Lydy (pp. 531-540).

This study investigated water quality of the Arkansas River and its tributaries in the Wichita, Kansas, area. Water quality assessment included an evaluation of urban versus agricultural areas using a twofold approach: (1) assessment of fish community health using an index of biotic integrity (IBI); and (2) analysis of organochlorine (OC) insecticides in fish tissue (Cyprinus carpio) and sediment samples via gas chromatography. Results of the IBI analysis indicated that the overall health of the fish community was poor. No significant difference existed among IBI scores at urban sites compared to agricultural sites; however, a pattern was noted with higher IBI scores at the agricultural sites. Total IBI scores and individual metrics were not statistically correlated to either normalized or non-normalized organochlorine concentrations in fish or sediment. Lindane, chlordane, 4,4′-DDT, and 4,4′-DDE were the most commonly detected OCs in sediment and fish tissue and often exceeded federal guidelines. Total OC concentrations and their detection frequency were significantly greater in urban than agricultural areas. In addition, a significant correlation was found among total OC concentrations in fish and sediment. This assessment concluded that overall water quality in the Wichita area was poor and that the urban area has significantly impacted water quality.

Can Excrement and Feathers of Nestling Songbirds Be Used as Biomonitors for Heavy Metal Pollution? by T. Dauwe; L. Bervoets; R. Blust; R. Pinxten; M. Eens (pp. 541-546).

Although birds have been frequently used as indicators of heavy metal pollution, few studies have examined pollutant levels in nestling passerines. In this paper we determined the levels of two essential (zinc and copper) and three nonessential heavy metals (lead, cadmium, and arsenic) in the excrement and feathers of great (Parus major) and blue tit (Parus caeruleus) nestlings at a polluted site (near a metallurgic factory) and a reference site (4 km farther east). The excrement of both great and blue tit nestlings contained significantly higher concentrations of arsenic, cadmium, copper, and lead at the polluted site. Zinc concentrations did not differ significantly between sites for both species. The feathers of great and blue tit nestlings accumulated significantly higher concentrations of lead at the polluted site than at the reference site. Zinc levels in the feathers of great tit nestlings were significantly higher at the reference site than at the polluted site. For all other elements considered, concentrations did not differ significantly between the two sites. There were no interspecific differences in metal levels between great and blue tits in both excrement and feathers. There was a significant positive correlation between the lead concentration in the excrement and feathers for both great and blue tits. We therefore conclude that excrement of great and blue tit nestlings can be used as a biomonitor for heavy metals (lead, cadmium, arsenic, and copper), whereas feathers appear only to be suitable as a biomonitor for lead pollution.

How Can We Use the Red Fox as a Bioindicator of Organochlorines? by S. Corsolini; L. Burrini; S. Focardi; S. Lovari (pp. 547-556).

The exposure of red foxes to hexachlorobenzene (HCB), dichlorodiphenyltrichloroethan (DDT), DDT derivatives, and polychlorinated biphenyls (PCBs) in central Italy was determined by analyzing muscle and adipose tissue samples from 57 red foxes collected in 1992–1993 in three areas of Tuscany, each characterized by different levels of anthropization. Chemical analysis showed that HCB occurred in low concentrations, ranging from an average of 0.08 μg/g lipid basis in fat of foxes from Pisa, the least agricultural area, to 1.06 μg/g in muscle of those from Grosseto, the least industrialized area. DDTs were calculated as the sum of the op′ and pp′DDT isomer concentrations and the DDT derivatives DDE and DDD. The lowest values of DDTs were found in foxes from Pisa, with mean values in muscle of 0.55 μg/g and 0.14 μg/g in fat. In the outskirts of Siena, the corresponding values were 1.16 μg/g and 0.49 μg/g. Higher values were found in the Grosseto area: 4.17 μg/g in muscle and 0.67 μg/g in fat. The most abundant DDT was pp′DDE in all areas, constituting more than half of total DDTs. Mean and standard deviations of PCB concentrations (calculated as the sum of the 31 identified and quantified congeners), were 20.2 μg/g in muscle and 7.2 μg/g in fat of red foxes from the Siena area. Values in the Pisa area were lower (7.6 μg/g in muscle and 1.8 μg/g in fat), whereas the highest levels were found in the Grosseto area (38 μg/g in muscle and 7.5 μg/g in fat). PCB fingerprints showed that hexa- and heptachlorobiphenyls were the most common congeners, although amounts differed between the three localities and the two tissues considered. As far as PCB composition is concerned, detailed observation revealed that although the three areas highly differed between each other, the most abundant congeners were the 22′344′5′ (PCB 138) and 22′44′55′ (PCB 153) hexachlorbiphenyls and 22′33′44′5 (PCB 170) and 22′344′55′ (PCB 180) heptachlorobiphenyls; these accounted for over 60% of total PCB residues in muscle and fat. Concentrations of the remaining PCB congeners were all lower than 5% of total PCBs, with the exception of octachlorobiphenyl 22′33′44′55′ (PCB 194) in fat tissue.Foxes may be suitable biological indicators to detect organochlorine contamination in the environment because of their catholic food habits. This information may be used to select specific bioindicators for assessing the relative level of pollutants in that area.

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Archives of Environmental Contamination and Toxicology (v.39, #4)