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PubMed1982

The relationships of salmonellae from infected broiler flocks, transport crates or processing plants to contamination of eviscerated carcases.

Three flocks raised for broiler or roaster performance tests were studied to determine the incidence and sources of salmonellae during the growing period, transport and processing and to relate these to contamination of processed carcasses. Day old chicks in two of the tests, (tests IV and V), were treated with a culture of intestinal anaerobes derived from mature chickens. The incidence of salmonellae during the growing period was too low to permit any conclusions about the efficacy of this culture in preventing Salmonella infection, but it had no adverse effect on flock performance. Carcasses from all three flocks were contaminated with salmonellae. Although the test IV flock was raised free of salmonellae, 46% of the carcasses tested from this flock were contaminated. The apparent source was the transport crates, 99% of which yielded salmonellae before the flock was loaded. In test V, 92% of the carcasses tested yielded salmonellae. The apparent sources were: flock infection (apparently originating from the parent flock), contaminated crates, spread during transport, and plant contamination. The flock of test VI was infected with Salmonella albany, and 54% of the carcasses tested were contaminated with this serovar. Carcasses of chicks infected early in life were more likely to be contaminated than those of chickens which contacted salmonellae later in the growing period.

Abattoirs↗

PubMed1981

Effect of laminar air flow and clean-room dress on contamination rates of intravenous admixtures.

The effect of laminar air flow conditions and clean-room dress on the microbial contamination rates of intravenous admixtures was investigated. Intravenous admixtures were prepared by one investigator using aseptic technique under four environmental conditions: laminar air flow conditions with clean-room dress; laminar air flow without clean-room dress; clean table top with clean-room dress; and clean table top without clean-room dress. In each environmental condition, 350 admixtures were compounded. Negative-control samples (n = 150) were also tested, as were 10 positive-control samples. Samples were tested in each of two growth media and incubated at 35 degrees C for 14 days or until growth occurred. The incidence of contamination of admixtures compounded in laminar air flow conditions was significantly less than the contamination of those compounded on a clean table top (p less than 0.05) regardless of the operator's dress. The incidence of contamination of admixtures compounded while wearing clean-room dress was not significantly different from those prepared while not wearing clean-room dress regardless of the environment in which the admixture was prepared. The overall low level of contamination [0.79% (11/1400)] was inconclusive regarding the effect of dress on the incidence of contamination when admixtures were prepared under LAF conditions. It is concluded that, when one adheres to aseptic technique, the environment in which admixtures are compounded is the most important variable affecting the microbial contamination rate.

Drug Compounding↗

PubMedDate not supplied

Microbiological evaluation of a newly designed dental air-turbine handpiece for anti-cross contaminations.

The effectiveness of a newly developed anti-cross contamination device for a dental air-turbine handpiece was tested. The handpiece with or without the anti-cross contamination device was contaminated with two bacterial strains, Staphylococcus aureus and Streptococcus mutans, as well as two bacteriophage strains, T2 and MS2. After contamination with these microorganisms, the handpieces were disinfected with glutaraldehyde or replaced with newly autoclaved ones. Residual microorganisms inside the handpiece or an air/water supply hose line were collected and counted after overnight cultivation. The anti-cross contamination device effectively reduced the contamination level of an air-turbine handpiece to that of the negative control. No microbial contamination in the air/water supply hose line was detected with this device.

Air Microbiology↗

PubMed1995

The secretion of radioactive iodine (131J) into the milk of small ruminants following their experimental contamination.

"Peak" levels of radioiodine (131J) in sheep and goats milk were reached between 12-24 hrs following their contamination. At the end of the nine days period for sheep and of 12 days period for goats, following a single contamination with the prescribed 131J dose, the radioiodine level is 0,25% of the contamination dose. Following a multiple biweekly radioiodine contamination, the corresponding radioactivity levels in milk are much higher than in blood. From the fourth day on, the ratio between the respective levels in milk and blood remains constant. Following a biweekly multiple contamination in goats, average concentration of 131J in thyroid is about 220% of the daily contamination dose, whereas the corresponding concentrations in milk and blood are 33% and 5% of the daily contamination dose. The corresponding values in sheep are 140% for thyroid and 26% and 3.5% for milk and blood. Chemicals used as "iodine metabolic inhibitors" do sensibly reduce radioiodine levels in milk, while simultaneously increasing the corresponding levels in blood.

Animals↗

PubMed1995

Anaesthetic drugs and bacterial contamination.

We investigated the bacterial contamination of commonly used intravenous anaesthetic agents. Ten trainee anaesthetists drew up four syringes each of propofol, midazolam, thiopentone, 0.9% saline and a culture medium control using their normal practice. A set of syringes was cultured at the time of drawing up and at 2, 4 and 8 h afterwards. No anaesthetist washed his or her hands before drawing up the drugs. Six anaesthetists capped the syringes using sheathed needles. Eight syringes were contaminated with bacteria. Coagulase-negative staphylococci were isolated from six syringes (four sheathed and two unsheathed) and an Acinetobacter sp. from two syringes (one sheathed and one unsheathed). No bacteria were cultured from the midazolam syringes. However, two syringes from each of the other solutions were contaminated. This implies that one syringe was contaminated when it was drawn up, at 2 h a further two had detectable contamination, two more were contaminated at 4 h and three more at 8 h. We cannot recommend drawing up drugs at the start of a list for use later in the day. They should be used immediately after drawing up. Basic hand washing before drawing up drugs may reduce contamination.

Anesthetics, Intravenous↗

PubMed1996

Survival of luxAB-marked Alcaligenes eutrophus H850 in PCB-contaminated soil and sediment.

A rifampicin-resistant PCB-degrading Alcaligenes eutrophus H850 strain was marked with luxAB reporter genes and designated H850Lr. This strain was enumerated in soil by viable plating and counting of light-emitting colonies. The marked strain was also inoculated into soil and sediment microcosms contaminated with PCBs and treated with rhamnolipid biosurfactants produced by Pseudomonas aeruginosa UG2Lr or inoculated with the P. aeruginosa UG2Lr strain. A. eutrophus H850Lr exhibited similar survival in sandy loam soil in the absence or presence of PCBs over 56 days. Survival of A. eutrophus H850Lr in PCB-contaminated sediment was less than in sandy soil under the same incubation conditions. Addition of P. aeruginosa UG2 rhamnolipids to soil increased the culturable indigenous heterotrophic population, and numbers of A. eutrophus H850Lr cells. P. aeruginosa UG2Lr cells did not affect survival of A. eutrophus H850, as cell enumerations after 2 months were the same as in microcosms containing only A. eutrophus H850 inoculum. P. aeruginosa UG2Lr survived in soils as demonstrated by the slight decrease in CFU from 1 x 10(8) to 2 x 10(6) CFU cm-3 after 2 months. Direct extraction of DNA from soil and purification for use in PCR amplification using primers specific for the bphC gene detected 8 x 10(2) A. eutrophus H850Lr CFU g-1 soil in PCB-contaminated soils. Colony lifts of bacteria isolated from microcosms containing PCB-contaminated soil did not hybridize with LB400 bphC probe. However, enrichment of PCB-contaminated soil with biphenyl, followed by DNA extraction and probing with bphC gene probe detected indigenous PCB-degrading bacteria containing a similar gene sequence in PCB-contaminated sediment. This study demonstrates the usefulness of using the lux reporter system in monitoring bacterial survival in PCB-contaminated soils and sediments.

Alcaligenes↗

PubMedDate not supplied

Highly sensitive chemiluminescent method for the detection of cell contamination.

Minisatellite analysis is commonly used in forensic disputes but can also be applied to the investigation of cell contamination. Such a problem arises, for example, when transplantation is performed. The presence of contamination has been investigated by other authors using radioactive methods. In the present study we describe a method that allows the detection of contamination with high sensitivity without using radioactive substances. Our technique is based on the use of polymerase chain reaction (PCR) amplification of minisatellite sequences (VNTR), followed by chemiluminescent detection. In particular, biotin-labelled dCTP is included in the PCR mixture and detection of PCR products is obtained following the CSPD chemiluminescent protocol (Southern-Light Nucleic Acid Detection Systems). We applied this method to artificial mixes of DNA of two individuals with alleles of different sizes. We performed progressive dilutions of an individual DNA into the other's DNA and revealed a contamination of 1 in 2500 cells. We also tested our technique searching for maternal contamination in cord blood samples in 60 cases and revealed a 18.3% contamination. The technique that we set up proves to be a very sensitive one which could be applied not only to the detection of maternal cells in cord blood but also in studying any other kind of contamination.

DNA↗

PubMed2001

Control of chemical risks during the treatment of soil contaminated with chlorophenol, creosote and copper-chrome-arsenic-wood preservatives.

BACKGROUND: Exposure to chemicals in polluted soil was studied during the remediation of four polluted sites. They are sawmill areas contaminated with chlorophenols and polychlorinated dibenzo-p-dioxins and furanes (PCDD/F), wood impregnating plants contaminated with polycyclic aromatic hydrocarbons (PAH) from creosote oil, old gas works area contaminated with PAH, and a wood impregnation plant contaminated with copper-chromium-arsenic (CCA) preservative. METHODS: The exposure levels were determined by both air and biological monitoring. RESULTS: Air monitoring showed that the exposure levels were generally well below the current occupational exposure limits. The calculations indicated, however, that the lowest acceptable daily intake value recommended for PCDD/F by the U.S. Environmental Protection Agency was exceeded. Chlorophenol exposure was generally low. Exposure to volatile PAH was 0.038-0.884 mg/m(3) and that to particulate PAH was 0.004-0.183 mg/m(3). The biomonitoring results (urinary 1-pyrenol) suggested that some exposure occurs, probably through the contamination of hands or skin absorption. At the sites contaminated with CCA salts, no exposure limits were exceeded. CONCLUSIONS: The results generally suggest that the exposure of cleanup workers is generally below the current occupational exposure limits but that short-term high exposure cannot be excluded. There was also some indication of poor skin protection, which should be improved when soil contaminated with PAH and creosote oil is handled.

Arsenic↗

PubMed1987

Maternal cell contamination in cultured chorionic villi: comparison of chromosome Q-polymorphisms derived from villi, fetal skin, and maternal lymphocytes.

Maternal cell contamination of chorionic villi (CV) samples used for first trimester prenatal diagnosis can cause obvious and/or unrecognized diagnostic dilemmas. The purpose of this investigation is to assess the frequency of maternal cell contamination (MCC) in chorionic villus samples and to evaluate selected parameters which might predict where contamination is more likely to have occurred. Maternal lymphocytes, chorionic villi from ultrasonically directed transcervical catheter aspiration, and fetal tissue were obtained at 8-11 weeks gestation from 45 patients undergoing elective termination. Quinacrine (Q) banded metaphases were compared from duplicate direct preparations of chorionic villi; cultured chorionic villi, fetal fibroblast tissue cultures, and maternal lymphocyte cultures. Q-polymorphisms in metaphase chromosomes were 100 per cent concordant between fetal tissue and direct CV preparation. However, evidence for maternal cell contamination occurred in 13.1 per cent of cultured chorionic villi preparations where polymorphisms were found to be identical between maternal and cultured CV and both distinct from fetal tissue preparations. Where MCC was identified, it was noted that CV cell cultivation interval was prolonged (24.2 +/- 6.8 days) compared with non-contaminated cultures (14.1 +/- 4.4 days) (p less than 0.05). We conclude that maternal cell contamination is a significant problem with chorionic villus sampling. Where direct preparations are not employed or when cultures are 'slow growing', MCC may be a significant and unrecognized complication re: fetal diagnosis. Direct preparations, multiple cultures, quinacrine banding, and maternal Q-polymorphism comparisons can minimize diagnostic dilemmas secondary to maternal cell contamination.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗

PubMed1996

Distribution of contaminants in aquatic organisms from East Fork Popular Creek.

The ecological risk assessment of East Fork Poplar Creek (EFPC) in Oak Ridge, Tennessee, investigated the nature and magnitude of the observed or expected adverse effects of the site's organic and inorganic contaminants on the ecosystem structure and function. Aquatic biota such as benthic macroinvertebrates, crayfish (Astacidae), redbreast sunfish (Lepomis auritus), and stonerollers (Campostoma anomalum), representative of various habitats, were sampled for whole-body contaminant analysis. The whole-body residue analysis of the representative aquatic organisms revealed the presence of over 50 contaminants in varying proportions. The relative whole-body distribution of organic contaminants such as mixtures of polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and pesticides was comparable among the indicator organisms. The relative whole-body distribution of inorganic contaminants was, however, less consistent. Physicochemical variables characteristic of organic contaminants--such as long octanol/water partition coefficient (log KOW), log aqueous solubility, and log bioconcentration factors (log BCF), and chemical uptake efficiency (E) unique for the organisms sampled for chemical analysis--were used to explain the observed whole-body distribution of contaminants in the aquatic organisms from EFPC.

Animals↗

PubMed2000

Lizard contaminant data for ecological risk assessment.

This review is the most comprehensive currently available of the effects and accumulation of environmental contaminants on lizards. The importance of lizards was emphasized in hope that they be included in ecological risk assessments as well as any study on environmental contamination. Some studies presented here indicated that lizards are ideal bioindicators. They are important as a component of biodiversity, and many species are listed as threatened or endangered. In addition, lizards are a significant part of many ecosystems as well as an important link in many food chains. There are large gaps in data for many environmental contaminants, particularly data on lizards. Ecotoxicological studies on a wide variety of lizard species are needed; both laboratory and field studies would provide useful information. Because the majority of lizards are insectivores, studies of the effects and accumulation of pesticides are essential. A few current studies are available from Africa and Australia, but most, especially those conducted in the U.S., were not current. Studies are needed on the effects and accumulation of ubiquitous contaminants, such as heavy metals and PCBs. Because of the many contaminated sites and the significant waste disposal problem, studies are needed on the effects and accumulation of radionuclides on lizards. Furthermore, effects of multiple stressors must be studied. Last, studies are needed linking the effects of contaminants to tissue residues. It is hoped that the convenience of having the vast majority of lizard environmental contaminant data available in one document will encourage its use.

Animals↗

PubMed1996

Host resistance to rat cytomegalovirus (RCMV) and immune function in adult PVG rats fed herring from the contaminated Baltic Sea.

The immunotoxic potential of many classes of environmental contaminants has been well established in laboratory studies, with much attention being focussed on aryl hydrocarbon (Ah)-receptor binding polychlorinated biphenyl (PCB), polychlorinated dibenzo-p-dioxin (PCDD), and polychlorinated dibenzofuran (PCDF) congeners. In a semi-field study, we previously showed that harbour seals (Phoca vitulina) fed herring from the contaminated Baltic Sea had lower natural killer cell activity, T-lymphocyte functionality and delayed-type hypersensitivity responses than seals fed herring from the relatively uncontaminated Atlantic Ocean. While ethical and practical constraints preclude in-depth studies in seals, specific reagents and a wider array of immune function tests allow such studies in laboratory rats. We therefore carried out a feeding study in rats aimed at extending our observations of contaminant-induced immunosuppression in harbour seals. The same two herring batches used in the seal study were freeze-dried, supplemented and fed to female adult PVG rats for a period of 4 1/2 months. Daily contaminant intakes of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalents (TEQ) were estimated to be 0.3 ng/kg body weight and 1.6 ng/kg in the Atlantic and Baltic groups, respectively. At the end of the feeding experiment, no contaminant-related changes in spleen CD4+/CD8+ cellularity, natural killer cell activity, or mitogen-induced proliferative responses of thymus or spleen cells could be detected. However, total thymocyte numbers and thymus CD4+/CD8+ ratios were reduced in the Baltic group. A novel model was established to assess the specific T-cell response to rat cytomegalovirus (RCMV). When applied to the feeding study, no differences between the Atlantic and Baltic groups in the RCMV-induced proliferative T-lymphocyte responses could be detected, but virus titres in salivary glands of infected rats of the Baltic Sea group were higher. These elevated RCMV titres and changes in thymus cellularity suggest that the dietary exposure to low levels of contaminants may have been immunotoxic at a level which our immune function test could not otherwise detect. While the herring diet per se appeared to have an effect on several immune function parameters, lower plasma thyroid hormone levels in the Baltic Sea group of rats confirmed that exposure to the environmental mixture of contaminants led to adverse PHAH-related health effects.

Animal Feed↗

PubMed2005

Assessment of a 2,4,6-trinitrotoluene-contaminated site using Aporrectodea rosea and Eisenia andrei in mesocosms.

Polynitro-organic compounds such as 2,4,6-trinitrotoluene (TNT) can be released into the environment from production and processing facilities and military firing ranges as well as through field use and disposal practices. Based on laboratory toxicity data, TNT has lethal (at >/=260 mg TNT/kg dry soil) and sublethal effects (at >/=59 mg TNT/kg dry soil) to the earthworm. However, field studies are needed to relate exposure of organisms to explosives in mixed-contaminated soil under field conditions and to define effects-based ecotoxicologic benchmarks for TNT-contaminated soil. In the present study, the lethal and sublethal effects of a 10-day in situ exposure at a TNT-contaminated field site using mesh-bag mesocosms were assessed. In addition to the survival end point, the biomarkers of earthworm exposure and effect-including tissue residues, lysosomal neutral red retention time (NRRT), and total immune activity (TIA)-were measured. Concentrations of TNT in soil mesocosms ranged from 25 to 17,063 mg/kg. Experiments indicated a trend toward decreasing survival of caged Aporrectodea rosea and Eisenia andrei as the concentration of TNT and total nitroaromatic compounds increased. E. andrei tolerated higher concentrations of TNT (up to 4050 mg/kg dry soil) in mesocosms than did indigenous earthworms, who survived only at </=1146 mg TNT/kg. Earthworms E. andrei and A. rose survived in 67% and 75% of TNT-contaminated mesocosms, respectively, compared with references groups. NRRT was significantly decreased in surviving earthworms from the contaminated areas compared with those from the reference site. TIA was not affected by field exposure to TNT. Earthworm tissue concentrations of TNT metabolites 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene were not correlated with TNT soil concentrations. In addition, higher tissue concentrations of TNT metabolites were observed at concentrations ranging from 116 to 130 mg TNT/kg soil. The results showed that earthworm exposure in TNT-contaminated soil produced both lethal and sublethal effects in the field. The results of study indicated that mesocosm experiments would be useful to assess the toxicity of a site and to characterize the overall effects of contaminants. However, mesocosm experiments present special considerations (e.g., abiotic factors, exposure period) when used at heterogenous sites, and data must be interpreted with caution.

Animals↗

PubMed2006

Effects of contaminants on reproductive success of aquatic birds nesting at Edwards Air Force Base, California.

Contamination by organochlorine pesticides (OCs), polychlorinated biphenyls, metals, and trace elements at Edwards Air Force Base (EAFB), located in the Mojave Desert, could adversely affect nesting aquatic birds, especially at the sewage lagoons that comprise Piute Ponds. Estimates of avian reproduction, in conjunction with analyses of eggs and avian foods for contaminant residues, may indicate the potential for negative effects on avian populations. From 1996 to 1999, we conducted studies at the Piute Ponds area of EAFB to evaluate the impacts of contaminants on nesting birds. Avian reproduction was evaluated in 1999. Eggs were collected for chemical analyses in 1996 and 1999, and African clawed frogs (Xenopus laevis), a likely food source, were collected for chemical analyses in 1998. Avian species occupying the higher trophic levels--black-crowned night-heron (Nycticorax nycticorax), white-faced ibis (Plegadis chihi), and American avocet (Recurvirostra americana)--generally bioaccumulated higher concentrations of contaminants in their eggs. Reproductive success and egg hatchability of night-herons and white-faced ibises in the Piute Ponds were similar to results observed at other western colonies. Deformities were observed in only one embryo in this study, but concentrations of contaminants evaluated in this ibis embryo were considered insufficient to have caused the deformities. Because clawed frogs, a primary prey item for night-herons at Piute Ponds, had no detectable levels of any OCs, it is likely that OCs found in night-heron eggs were acquired from the wintering grounds rather than from EAFB. The presence of isomers of dichlorodiphenyltrichloroethane (DDT) in ibis eggs indicated recent exposure, but invertebrates used for food by ibises were not sampled at Piute Ponds, and conclusions about the source of OCs in ibis eggs could not be made. Concentrations of contaminants in random and failed eggs of individual species were not different, and we concluded that contaminants did not cause the observed egg failures.

Abnormalities, Drug-Induced↗

PubMed2000

Ecotoxicity of contaminated suspended solids for filter feeders (Daphnia magna).

It is generally assumed that the dissolved fraction of a toxic substance in surface water is mainly responsible for toxicity to aquatic organisms. However, toxic compounds are often adsorbed or chemically bound to suspended particles in the water column, depending upon the physico-chemical conditions. In the present study potential adverse effects to filter feeding organisms by metal contaminated particles were investigated. In our hypotheses the adsorbed metals might desorb in the gastrointestinal tract-due to different physico-chemical conditions-and exert toxic effects. Clay and sand particles, algae and organic material (peat) were artificially contaminated with cadmium and zinc. The contaminated materials were resuspended in standard conditions and toxicity was measured for the water flea Daphnia magna (mortality at 48 hours). As a reference, supernatant solutions were used containing the same concentration of dissolved metal as the suspensions. It was also established that the test concentrations of solid material (250 and 500 mg/l uncontaminated particles) did not cause any mortality within 48 hours. Daphnids are filter feeders: they filtrate large amounts of surrounding water, redrawing particles as a food source. Results strongly indicate that contaminated particles threaten the health of these particle-feeding organisms. Compared to the reference severe acute toxic effects were seen and cadmium accumulation was increased when contaminated solid material was present. Results were essentially the same for the different materials used in the experiments, except for sand contaminated with cadmium. This shows that mineral as well as organic materials can contribute to the particle bound toxicity. Different results were obtained when a static set up was used instead of a flow through set up, illustrating that the route of administration is important to make particles available and thus to evaluate their toxicity. Contaminated particles clearly have toxic potency, not only because they are a continuous source of dissolved xenobiotics, but also because the particle bound fraction can become available within the body of particle feeding organisms. This could lead to unexpected high tissue concentrations. More insight is needed to predict the bioavailability of adsorbed pollutants. Results of this study already indicate that suspended solids should be considered as a separate compartment in risk evaluation of chemicals, effluents or natural surface waters.

Animals↗

PubMed2001

Evaluation of contamination, by different elements, in terrestrial mosses.

Evaluation was made of the degree to which samples of terrestrial mosses (Scleropodium purum and Hypnum cupressiforme) collected in Galicia (NW Spain) were contaminated by different elements. The concentrations of Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, S, Se, and Zn in the mosses were determined, then the contamination factors were calculated by dividing each value by the corresponding background level of that element. To assess contamination using contamination factors (CFs), a scale was established that allowed categorization of sampling sites for each element determined. The proposed scale comprises six categories, ranging from CF values of less than 1 (no contamination) to values of greater than 27 (extreme contamination). Finally, all available information was brought together and summarized in a contamination index. This index has the advantage that it takes into account the toxicity of the elements and that can be used with an already existing scale of classification.

Air Pollution↗

PubMed2001

Accumulation and selective maternal transfer of contaminants in the turtle Trachemys scripta associated with coal ash deposition.

Coal combustion wastes are enriched in a number of potentially toxic compounds and may pose risks to biota exposed to the wastes. Slider turtles (Trachemys scripta) are common inhabitants of coal ash settling basins in South Carolina, USA, where they feed on contaminated prey items and accumulate high levels of potentially toxic compounds in their tissues. Furthermore, female sliders sometimes nest in contaminated spill piles and thus may expose embryos to contaminated soils. We examined two potential pathways by which female T. scripta may influence the survivorship and quality of their offspring in a contaminated habitat: (1) nesting in contaminated soil and (2) maternal transfer of pollutants. Eggs were collected from turtles captured in coal ash-polluted or unpolluted sites; individual clutches were incubated in both ash-contaminated and uncontaminated soil in outdoor, artificial nests. Incubation in contaminated soil was associated with reduced embryo survivorship. Adult females from the polluted site accumulated high levels of As, Cd, Cr, and Se in their tissues, yet Se was the only element transferred maternally to hatchlings at relatively high levels. Hatchlings from polluted-site females exhibited reduced O2 consumption rates compared to hatchlings from reference sites. Relatively high levels of Se transferred to hatchlings by females at the ash-polluted site might contribute to the observed differences in hatchling physiology.

Animals↗

PubMed1999

Organochlorine contamination in bald eagle eggs and nestlings from the Canadian Great Lakes.

Unhatched eggs and plasma samples from prefledged bald eagles (Haliaeetus leucocephalus) from a recovering population in the Canadian Great Lakes Basin were contaminated with organochlorine compounds at levels comparable to those reported for eagle populations in several areas of the United States. PCBs were among the most commonly detected contaminants and occurred at high concentrations in plasma. Plasma PCB concentrations in Lake Erie nestlings were significantly higher than in chicks from Lake Nipigon (0.130 and 0.047 mg/kg wet weight, respectively). Blood levels of mirex were higher in nestlings from Lake Superior compared to those from Lake Erie (0.0012 and 0.0006 mg/kg wet weight, respectively). Migration routes and over-winter locations of avian prey that constitute a part of the bald eagle chick's diet are likely to contribute to these spatial contaminant patterns in plasma. Atmospheric deposition and a cold condensation effect for chlordane compounds may have produced higher levels of these compounds in plasma samples from Lake Superior compared to samples from Lake Erie (0.020 and 0.008 mg/kg wet weight, respectively). Levels of DDE in plasma were generally low, ranging in concentration from 0.02 mg/kg wet weight for lakes Erie and Nipigon to 0.06 mg/kg wet weight for Lake Huron. Concentrations of organochlorines in eaglet plasma remained relatively stable between 1990 and 1996; no significant trends associated with year of sampling were detected. The data from Lake Erie showed no correlation between productivity and plasma levels of PCBs or DDE during this time period. There were no indications that the concentrations of contaminants detected were adversely affecting productivity in Canadian Great Lakes bald eagle populations. Residue levels in eggs from Lake Erie eagle territories were equally or more contaminated than eggs from other highly contaminated environments in the United States such as the Great Lakes and Columbia River estuary. Concentrations of DDE and PCBs in Lake Erie eggs declined significantly between 1974 and 1994. Although dieldrin and chlordane levels showed a similar decline, these relationships were not statistically significant. Mirex concentrations were relatively stable. Eggs from Lake of the Woods were significantly less contaminated than those from Lake Erie (PCBs: 3 and 84 mg/kg wet weight, respectively; DDE: 3 and 24 mg/kg wet weight, respectively). Reproductive success (number of young produced/active nest) remained constant between 1982 and 1996 and productivity is sufficient to maintain an increasing population. The number of active nests has increased during this period indicating that the population is expanding and might be expected to do so until suitable habitat becomes limiting. Reductions in organochlorine levels, reintroduction efforts, immigration from other populations, and changes in habitat quality have likely contributed to the observed growth in the number of breeding pairs.

Animals↗