Pathologic impacts of contaminants in freshwater fish of Cook County IL.

Mercury (Hg) and polychlorinated biphenyls (PCBs) are widespread environmental toxicants in urban environments with negative impacts to fish health. The present study evaluated the potential association between muscle tissue contaminant (total Hg and total PCB) concentrations and indicators of health in benthic and predatory fish collected from four Forest Preserves of Cook County lakes in the Chicago metropolitan area. Common carp (carp; Cyprinus carpio) and largemouth bass (LMB; Micropterus salmoides) were sampled three times a year (spring, summer, fall) during 2019 and 2020. Water quality analyses (temperature, color, turbidity, dissolved oxygen, total alkalinity, pH, chloride, nitrate, phosphate, ammonium, and pH) were performed concurrently with fish collections. Tissue (skin-on fillet) contaminant concentrations were compared between lake types and fish species and assessed for any relationship with fish morphometric data and pathologic lesions. Main health indicator endpoints included muscle lipid content, parasite burden, and pathologic lesions. Mean total PCB concentrations were greater in carp (203.1 ± 152 µg/kg, wet weight), and mean Hg concentrations were greater in LMB (0.11 ± 0.1 mg/kg, wet weight). In most fish, concentrations of both toxicants surpassed the EPA's lowest threshold to restrict fish consumption for sensitive cohorts (0.029 mg/kg for Hg and 1.5 µg/kg for PCBs). In both species, Hg positively correlated with splenic pigmented macrophage aggregate area (P < 0.001). In carp, Hg also positively correlated with hepatocellular pigmentation (P < 0.01). Mercury correlated with standard length in both species (LMB: P < 0.001, carp: P = 0.95), but polychlorinated biphenyls only correlated with standard length in carp (P < 0.001). No association was found between intraspecific contaminant concentrations and parasite burden, year, or lake type, though differences were noted among individual lakes. The contaminant burden appeared well-tolerated with only mild Hg-associated and no appreciable PCB-associated lesions. However, possible effects on reproduction or behavior were not fully assessed, and future studies are warranted.

Effects of nest type and sex on blood saccharide profiles in Humboldt penguins (Spheniscus humboldti): Implications for habitat conservation.

Reproductive success of endangered Humboldt penguin (Spheniscus humboldti) colonies in Peru has been associated with nesting habitat type, presumably due to differences in environmental exposure and activity patterns that may affect energy demands and metabolism. Gas chromatography and mass spectrometry were used to determine serum concentrations of 19 saccharides from 30 Humboldt penguins nesting at Punta San Juan, Peru in order to evaluate differences in metabolic state between penguins nesting in a sheltered burrow or crevice (n = 17) and those in exposed surface nests (n = 13). Univariate and multivariate statistical analyses identified serum saccharides (arabinose, maltose, glucose-6-phosphate, and levoglucosenone in particular) that were nest-dimorphic with substantial differences between surface- and sheltered-nesting penguins. Four sugars (arabinose, xylose, fructose-6-phosphate, and sucrose) had ≥ 2-fold difference in concentration between nest types. Seven saccharides were in the top five subsets generated by discriminant analysis; four of these are simple sugars (D-glucopyranose, α ⇄ ß; D-glucose; D-maltose; and D-mannose) and three are derivatives (glucose 6-phosphate, levoglucosenone, and N-acetylglucosamine). D-ribose had the highest information values (generated from weight-of-evidence values) followed by glucose 6-phosphate, levoglucosenone, and D-galactose. Sex was not a significant predictor of saccharide concentration. Levoglucosenone, which is a metabolite of the environmental contaminant levoglucosan, was significantly higher in surface-nesting penguins, reflecting a higher rate of exposure in non-sheltered penguins. Differences in the saccharide profiles of surface- and sheltered-nesting Humboldt penguins likely reflect increased metabolic requirements of surface-nesters at Punta San Juan. Conservation of appropriate sheltered-nesting habitat for penguins is essential for sustained reproductive success and colony health.

Analysis of Toxic and Essential Elements in the Blood and Feathers of Humboldt Penguins ( Spheniscus humboldti) at Punta San Juan, Peru.

Whole blood, serum, and feather samples from 29 Humboldt Penguins ( Spheniscus humboldti) at the Punta San Juan Marine Protected Area, Peru, were analyzed for 55 toxic and essential elements by using inductively coupled plasma mass spectrometry. Mercury (Hg) was analyzed by cold vapor atomic fluorescence. Maximum Hg concentrations in serum (0.0056 mg/g), whole blood (0.297 mg/kg), and feathers (1.8 mg/kg dry weight) were at levels generally not considered to cause health impairment. Of the elements analyzed, only eight (aluminum, calcium, iron, Hg, potassium, magnesium, sodium, and zinc) were detected in serum. These elements, plus selenium and titanium, were also quantifiable in whole blood. Feather analysis detected quantifiable values for the elements found in serum, plus arsenic, boron, barium, copper, manganese, and titanium. Results indicate this important breeding population of endangered penguins did not appear to be exposed to environmental elemental contaminants at levels detrimental to health and reproductive success. However, identification of measurable concentrations of toxic elements at low levels underscores the need for continued environmental monitoring, particularly in the face of expanding regional human populations and industrial growth. These results provide important reference data for temporospatial monitoring of this and other penguin populations.

Associations of intestinal helminth infections with health parameters of spring-migrating female lesser scaup (Aythya affinis) in the upper Midwest, USA.

Thousands of lesser scaup (Aythya affinis) die during spring and fall migrations through the upper Midwest, USA, from infections with Cyathocotyle bushiensis and Sphaeridiotrema spp. (Class: Trematoda) after ingesting infected intermediate hosts, such as non-native faucet snails (Bithynia tentaculata). The lesser scaup is a species of conservation concern and is highly susceptible to these infections. We collected female lesser scaup from spring migratory stopover locations throughout Illinois and Wisconsin and assessed biochemical and morphological indicators of health in relation to intestinal helminth loads. Helminth species diversity, total trematode abundance, and the infection intensities of the trematodes C. bushiensis and Sphaeridiotrema spp. were associated with percent body fat, blood metabolites, hematological measures, and an index of foraging habitat quality. Helminth diversity was negatively associated with percent body fat, albumin concentrations, and monocytes, whereas glucose concentrations displayed a slight, positive association. Total trematode abundance was negatively associated with blood concentrations of non-esterified fatty acids and albumin. Infections of C. bushiensis were positively related to basophil levels, whereas Sphaeridiotrema spp. infection intensity was negatively associated with packed cell volume and foraging habitat quality. Thus, commonly measured health metrics may indicate intestinal parasite infections and help waterfowl managers understand overall habitat quality. Intestinal parasitic loads offer another plausible mechanism underlying the spring condition hypothesis.

Metal Concentrations in Tissues of Gadwall and Common Teal from Miankaleh and Gomishan International Wetlands, Iran.

Miankaleh and Gomishan International Wetlands are important wintering areas for waterbirds in the Caspian Sea region. Previous studies revealed increased exposure to metals in some species of waterbirds using these wetlands. In this study, we examined concentrations of cadmium (Cd), chromium (Cr), iron (Fe), lead (Pb), and zinc (Zn) in kidneys, liver, and pectoral muscle of wintering Gadwall (Anas strepera) and Common Teal (Anas crecca) collected in 2012. In addition, we measured concentrations of these elements in water and sediments from the collection sites. The genders differed in only one element/tissue combination, i.e., concentrations of Fe were greater in the livers of males. Concentrations of elements observed in Gadwall were generally higher than in Common Teal; only renal Cr and muscle Zn did not differ between species. Mean Cd concentrations in Gadwall exceeded background levels, reaching 1.94 µg/g ww in kidneys and 1.09 µg/g ww in liver. Similarly, Pb concentrations in Gadwall were also elevated (4.14 µg/g ww in kidneys, 3.22 µg/g ww in liver). Concentrations of other metals were within ranges commonly found in waterfowl. Concentrations of elements in the environment were elevated above background and comparable with the data obtained for this region by other scientists. However, these levels were deemed to not be great enough to pose an acute health risk to waterfowl. Given increased concentrations of some metals in duck tissues, further inquiry into the source of the exposure is needed for this area.

ASSESSMENT OF POLYCHLORINATED BIPHENYLS, ORGANOCHLORINE PESTICIDES, AND POLYBROMINATED DIPHENYL ETHERS IN THE BLOOD OF HUMBOLDT PENGUINS ( SPHENISCUS HUMBOLDTI) FROM THE PUNTA SAN JUAN MARINE PROTECTED AREA, PERU.

Persistent organic pollutants were assessed in Humboldt Penguins ( Spheniscus humboldti) from the Punta San Juan Marine Protected Area, Peru, in the austral winter of 2009. Plasma samples from 29 penguins were evaluated for 31 polychlorinated biphenyl (PCB) congeners and 11 organochlorine pesticides (OCPs) by using gas chromatography coupled to an ion trap mass spectrometer and for 15 polybrominated diphenyl ether (PBDE) congeners by using gas chromatography coupled with high-resolution mass spectrometry. The detection rate for PCBs in the samples was 69%, with congeners 105, 118, 180, and 153 most commonly detected. The maximum ΣPCB concentration was 25 ng/g. The detection rate for DDT, DDD, and/or DDE was higher than for other OCP residues (90%; maximum concentration=10 ng/g). The detection rate for PBDEs was 86%, but most concentrations were low (maximum ΣPBDE concentration=3.81 ng/g). This crucial breeding population of S. humboldti was not exposed to contaminants at levels detrimental to health and reproductive success; however, the identified concentrations of legacy and recently emerged toxicants underscore the need for temporal monitoring and diligence to protect this endangered species in the face of regional human population and industrial growth. These results also provide key reference values for spatial comparisons throughout the range of this species.

Study on Metal Concentrations in Tissues of Mallard and Pochard from Two Major Wintering Sites in Southeastern Caspian Sea, Iran.

We examined concentrations of cadmium, chromium, iron, lead and zinc in the kidney, liver, and pectoral muscle of Mallards (Anas platyrhynchos; n = 30) and Pochards (Aythya ferina; n = 30) from two important wintering sites in the southeastern Caspian Sea in the winter of 2012. Mean lead concentrations (µg g(-1) ww) in livers (2.36 ± 1.00) of Pochard and in kidneys (3.43 ± 0.91) of Mallard exceeded the exposure threshold levels in liver (1.5 µg g(-1) ww) and kidney (3 µg g(-1) ww) of waterfowl. Mean cadmium concentrations in livers (1.63 ± 0.66) of Pochards exceeded the background level of this metal in liver (1 µg g(-1) ww) of waterfowl. Chromium, iron and zinc concentrations were within the normal range as reported in other duck studies. Gender-related and inter-specific variation of metal concentrations in analyzed tissues were observed (t test, p < 0.05). Our results indicated that waterfowl using the Miankalah and Gomishan International Wetlands are being exposed to elevated concentrations of cadmium and lead.

Polyaromatic hydrocarbons and elements in sediments associated with a suburban railway.

Railroad operations are a potential source for contamination of aquatic ecosystems. We examined concentrations of polyaromatic hydrocarbons (PAHs) and selected elements in sediments collected during 2009-2011 from streams, ditches, or ponds bisected or bordered by the former Elgin, Joliet, and Eastern rail line in the western Chicago, Illinois, metropolitan area. Summed PAH concentrations were greater in sediments collected downstream than in those collected upstream of the railroad and were negatively associated with distance within 500 m of the tracks. Phenanthrene and dibenzo (a,h)anthracene concentrations at some locations exceeded probable effect thresholds for risks to aquatic life. Although maximum levels of chromium (Cr) were below levels of concern, we did not determine the valence state of Cr; thus, risks to aquatic life could not be fully evaluated. Nickel and mercury concentrations exceeded lower effect levels, and vanadium concentrations exceeded chronic toxicity thresholds at some locations, although we did not detect an association between these elements and the presence of the railroad. Lead and arsenic concentrations were greater in proximity to the railroad; however, concentrations were below thresholds of concern for aquatic life. Our results suggest that the railroad and associated activities are contributing some environmental contaminants to waterways in close proximity to it, particularly in a downstream direction. Risks to aquatic life may be greater than implied by observed concentrations of individual contaminants, as synergistic adverse effects are likely to occur with exposure to complex mixtures.

Metabolite Profiles of Male and Female Humboldt Penguins.

We examined 185 metabolites in 30 adult Humboldt Penguins (Spheniscus humboldti) nesting at the Punta San Juan Marine Protected Area, Peru, in order to examine gender differences in metabolome profiles, particularly those involved in metabolism and energetics. The majority of the compounds identified were fatty (26% of total identified compounds), organic (19%), and amino (16%) acids. We were able to differentiate male and female penguins with 96.6% accuracy on the basis of 12 metabolites, most of which are involved in lipid and carbohydrate metabolism. These included 2-oxoglutarate, erythronic acid, GABA, mannitol, sedoheptulose 7-phosphate, and serine and six metabolites present in higher concentrations in females compared to males (2-aminoadipic acid, O-phosphorylethanolamine, glycerol 2-phosphate, glycerol 3-phosphate, pantothenic acid, and creatinine). Of these, 2-oxoglutarate and glycerol 3-phosphate were key metabolites distinguishing gender. Our results indicated that male and female Humboldt Penguins were characterized by differing metabolic states. Such differences could be important to individual and brood survival in times of environmental stress.

Elements of concern in fillets of bighead and silver carp from the Illinois River, Illinois.

Efforts to control invasive bighead (Hypophthalmichthys nobilis) and silver carp (H. molitrix) may include harvest for human consumption. We measured concentrations of arsenic (As), mercury (Hg), and selenium (Se) in fillets from silver and bighead carp collected from the lower Illinois River, Illinois, USA, to determine whether concentrations were of health concern and differed by species, size, and location. Concentrations of total As were below detection limits in most bighead (92%) and silver (77%) carp fillets, whereas inorganic As was below detection limits in all samples. Mean Hg concentrations were greater in bighead (0.068 mg kg(-1)) than in silver carp (0.035 mg kg(-1)), and were smallest in carp from the confluence of the Illinois and Mississippi rivers. Mercury concentrations in fillets were positively correlated with body mass in both species. Concentrations of Hg were below the US Food and Drug Administration's (USFDA) action level (1 ppm as methyl-Hg); however, concentrations in some bighead (70%) and silver (12%) carp fell within the range that would invoke a recommendation to limit meals in sensitive cohorts. Mean Se concentrations were greater in silver (0.332 mg kg(-1)) than in bighead (0.281 mg kg(-1)) carp fillets, and were below the 1.5 mg kg(-1) limit for an unrestricted number of meals/month. The mean molar ratio of Se:Hg in fillets was lower in bighead (14.0) than in silver (29.1) carp and was negatively correlated with mass in both species Concentrations of Hg in bighead and silver carp fillets should be considered when assessing the risks associated with the use of these species as a protein source.

Spatial and interspecific patterns in persistent contaminant loads in bighead and silver carp from the Illinois River.

We measured concentrations of selected organohalogens, fluorinated compounds and mercury in whole, ground silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp from the Illinois River, Illinois, in 2010 and 2011 to characterize spatial and interspecific patterns of contaminant burdens. Silver carp, which had greater lipid content, tended to have greater concentrations of lipophilic compounds. Concentrations of organohalogens were generally greater in carp from the upper reaches of the river. The halogenated compounds were associated with length and lipid content in silver carp. Bighead carp had greater mercury concentrations than did silver carp; total mercury concentrations were negatively associated with lipid content of bighead carp. Perfluorinated compounds, comprised predominantly of perfluorooctane sulfonic acid, did not vary by species or river reach. Chlordanes and polychlorinated biphenyls were of potential concern with regard to the use of these carp as animal feed additives. Our results indicated that, even though they occupy a lower trophic level than many similarly-sized fish, these carp may accumulate measureable concentrations of organic contaminants.

Mercury in small Illinois fishes: historical perspectives and current issues.

Documenting long-term trends in mercury deposition and/or accumulation is important in setting regulatory benchmarks, modeling contaminant transfer and flux, measuring success of environmental controls, and even assigning responsibility for pollution. We conducted a study to compare mercury concentrations in small fishes from "high-mercury" and "low-mercury" regions of Illinois, as well as to examine historic patterns of mercury availability using preserved fishes. Mercury concentrations were greater in four species of small fishes collected from a stream in a "high-mercury" region than in those same taxa collected from a stream in a "low-mercury" area in Illinois. Mercury concentrations in blackstripe topminnows (Fundulus notatus) declined dramatically between 1900 and 1961/2006 in the "high-mercury" stream, presumably due reductions in mercury releases from local and regional sources. Preserved fish had an apparent increase in mercury concentrations for up to 12 months, which is consistent with changes in mass and loss of proteins observed in other studies, and we recommend that recent samples be preserved for at least 12 months before comparison with older fluid-preserved material. Based on our results, further studies of mercury in small fishes in Illinois streams appear warranted.

Hematologic and blood chemistry reference values for free-ranging muskrats (Ondatra zibethicus).

Baseline hematologic and serum chemistry values are used by veterinarians and wildlife biologists to identify abnormally high or low levels of particular blood parameters in a target species. This vital information can assist animal care providers in making informed decisions on the care of wildlife and help to determine diagnoses for certain illnesses. Published blood parameter values are not available for wild-caught muskrats (Ondatra zibethicus). We measured 27 blood parameter values from 29 free-ranging, riparian muskrats caught from June-November 2008 in east-central Illinois, USA, and compared mean values between adults and juveniles. Adult muskrats had higher levels of globulins (F(1,27)=6.394, P ≤ 0.018) and eosinophils (F(1,25)=6.883, P ≤ 0.015) than did juvenile muskrats, possibly because of increased exposure to parasites and allergens over time.

Polycyclic aromatic hydrocarbons in fish and crayfish from the Calumet region of southwestern Lake Michigan.

We identified and quantified polyaromatic hydrocarbons (PAHs) in six aquatic taxa from the Calumet region of southwestern Lake Michigan in order to examine their differential exposure to and health risks from PAH. There was a high degree of variation in PAH concentrations across and within sites. Mean concentrations of total PAH were high in alewife (1,064 ng/g) and minnows (345 ng/g) collected from the Indiana Ship Canal, when compared to other taxa and locations. Concentrations of PAH in sunfish were relatively low (10 to 79 ng/g), even where environmental concentrations were elevated. In sunfish, regardless of location, concentrations of CHR, FLA, FLU, PHE and PYR were high whereas DBA, IPE, BAP, BBF, BGP and BKF concentrations were low. PAH concentrations in crayfish exceeded those of other taxa at three of four locations where they co-occurred. PAH profiles were similar in crayfish, sunfish and minnows from locations where sediment concentrations were low. Profiles for crayfish and minnows from a location where sediment concentrations were elevated displayed lower concentrations of ACY, and higher concentrations of BAA, BBF, and BKF, than those from the other three locations. In contrast, the profiles in sunfish from those three locations were similar. The PHE/ANT and FLA/PYR ratios for crayfish, minnows and sunfish suggested that the primary sources at most locations were pyrogenic, although some sites had strong petrogenic influences. Toxic equivalency factors in biota generally reflected the magnitude of sediment contamination. In three of four locations where they co-occurred, TEQs were higher in crayfish than in sunfish and minnows. Sunfish had higher TEQs than minnows at most, though not all, locations; TEQs were notably higher in minnows as compared to sunfish from the Little Calumet River. The selection of aquatic species as sentinels of PAH exposure and risks needs to consider differences in ecologies of taxa as well as the relative magnitude of sediment contamination.

Heavy metal exposure, reproductive activity, and demographic patterns in white-footed mice (Peromyscus leucopus) inhabiting a contaminated floodplain wetland.

We examined the concentrations of selected metals and selenium (Se) in the tissues of white-footed mice (Peromyscus leucopus) collected at a constructed wetland originally created as a retention basin for sediments dredged from Lake DePue, Illinois. These sediments were contaminated with high concentrations of cadmium (Cd), zinc (Zn), and other elements as a result of nearby smelting operations. White-footed mice inhabiting the former retention basin experienced greater exposure to Cd, Pb, and Se than those from nearby reference sites. Concentrations of Cu and Zn in livers of mice from the contaminated wetland and adjacent floodplain reference site were greater than in mice from the more-distant reference sites. Judging by concentrations in their kidneys, white-footed mice inhabiting the floodplain adjacent to the contaminated wetland had greater exposure to Cd than those from the two more-distant reference sites. Concentrations of Hg in tissues of mice did not vary appreciably among sites. Concentrations of Cd and Se in the tissues of some white-footed mice from the contaminated wetland exceeded critical concentrations observed in experimental studies of laboratory mice and rats; with few exceptions tissue Pb concentrations were below published effects levels. However, we did not detect changes in abundance, demographics, or reproductive activity that might suggest population-level effects of contaminant exposure. Mean weight of embryos expressed as a function of crown-rump length did not differ among locations sampled, and no gross lesions indicative of exposure to heavy metals were observed. Kidney and liver weight, corrected for body weight, were nominally, though not significantly, lowest in both male and female mice from areas of increased Cd and Pb exposure. Metals dredged from Lake DePue were still bioavailable 25 years after deposition. However, small mammal populations are resilient to environmental stressors and we did not detect differences in population parameters suggesting that the population of white-footed mice inhabiting the contaminated wetland was at risk from increased exposure to these contaminants.

Fate of tritiated didemnin B in mice: excretion and tissue concentrations after an intraperitoneal dose.

Didemnin B has undergone trials in cancer patients, and has antiviral and immunosuppressive properties. [(3)H]didemnin B was administered intraperitoneally (i.p.) to mice at 320 or 1280 microg/kg. Urine and feces were collected until 168 h, at which time the mice were killed and tissues collected. Additionally, [(3)H]didemnin B was given i.p. at 320 microg/kg, and mice were killed at 1-120 h post-dosing. Radiolabel increased rapidly in blood then rapidly declined. Most radiolabel in urine, feces and tissues represented parent compound. Concentrations of [(3)H]didemnin B were greatest in the liver > gallbladder > lower digestive tract congruent with pancreas > spleen > kidney congruent with adipose tissue congruent with urinary bladder with urine. The pancreas had the longest terminal half-life of the tissues and the highest radioactivity at 7 days. Intermediate concentrations were in the duodenum congruent with jejunum > lung > iliopsoas > stomach congruent with testes congruent with skin > heart. Low concentrations were in the humerus congruent with femur congruent with quadriceps congruent with triceps >> brain. Fecal excretion accounted for 45.9%-58.3% of the dose and declined after 24 h, followed by an increase, suggesting possible enterohepatic recycling or an impact of circadian rhythms. Urinary excretion accounted for 18.4%-25.2% of the dose, but was minimal after 24 h. The concentrations were highest in organs previously found to be sensitive in animals and humans. Didemnin B should be evaluated in animal models for treatment of pancreatic cancer.

Intersexuality and the cricket frog decline: historic and geographic trends.

Exposure to anthropogenic endocrine disruptors has been listed as one of several potential causes of amphibian declines in recent years. We examined gonads of 814 cricket frogs (Acris crepitans) collected in Illinois and deposited in museum collections to elucidate relationships between the decline of this species in Illinois and the spatial and temporal distribution of individuals with intersex gonads. Compared with the preorganochlorine era studied (1852-1929), the percentage of intersex cricket frogs increased during the period of industrial growth and initial uses of polychlorinated biphenyls (PCBs) (1930-1945), was highest during the greatest manufacture and use of p,p-dichlorodiphenyltrichloroethane (DDT) and PCBs (1946-1959), began declining with the increase in public concern and environmental regulations that reduced and then prevented sales of DDT in the United States (1960-1979), and continued to decline through the period of gradual reductions in environmental residues of organochlorine pesticides and PCBs in the midwestern United States (1980-2001). The proportion of intersex individuals among those frogs was highest in the heavily industrialized and urbanized northeastern portion of Illinois, intermediate in the intensively farmed central and northwestern areas, and lowest in the less intensively managed and ecologically more diverse southern part of the state. Records of deposits of cricket frog specimens into museum collections indicate a marked reduction in numbers from northeastern Illinois in recent decades. These findings are consistent with the hypothesis that endocrine disruption contributed to the decline of cricket frogs in Illinois.

Assessment of erythrocyte morphologic abnormalities in mallards with experimentally induced zinc toxicosis.

OBJECTIVE: To describe and quantify morphologic abnormalities in RBCs of mallards (Anas platyrhynchos) with experimentally induced zinc toxicosis. ANIMALS: 120 female mallards. PROCEDURE: Farm-raised mallards (6 to 8 months old) were used in the study. On day 0, 60 ducks received shot pellets orally by gavage (mean dose of zinc, 0.97 g); another 60 ducks underwent the same procedure without administration of pellets. On day 15, Romanowsky-stained blood smears were prepared from 53 control and 45 zinc-treated ducks (smears were examined retrospectively). In each smear, 200 RBCs were examined and numbers of erythrocytes with abnormal size, shape, or color were expressed as a percentage. Results were compared with PCV values and zinc dose. RESULTS: Mean PCV value was lower in all zinc-treated ducks, compared with control ducks, and was lower in zinc-treated ducks that died or were euthanatized before day 30 because of severe clinical disease, compared with those that survived. Zinc-treated ducks that survived had a high percentage of polychromatophilic RBCs, and those that that died before day 30 had high percentages of hypochromic RBCs, fusiform RBCs, and RBC nuclear abnormalities. There was no correlation between PCV value or RBC morphologic abnormalities and dose of zinc. CONCLUSIONS AND CLINICAL RELEVANCE: In ducks with severe zinc-induced hemolysis, findings indicated that functional iron deficiency may impair the effectiveness of the erythroid regenerative response and contribute to death. Erythrocyte nuclear abnormalities were consistent with mild dyserythropoiesis. These findings may be applicable to effects of other metal toxicoses and regenerative anemias in birds.

Cadmium and lead in tissues of Mallards (Anas platyrhynchos) and Wood Ducks (Aix sponsa) using the Illinois River (USA).

Cadmium and lead concentrations were determined in the tissues of Mallards and Wood Ducks collected from two waterfowl management areas along the Illinois River, USA, during the autumn and late winter of 1997-1998. Lead concentrations in livers of Mallards were lower than previously reported, and, along with those in a small sample of Wood Duck livers, were within background levels (<2.0 microg/g wet weight). Mean concentrations of cadmium in the kidneys of Wood Ducks utilizing the Illinois River were four times greater than in after-hatch-year Mallards, and 14 times greater than in hatch-year Mallards. Concentrations of cadmium in the kidneys of Wood Ducks were comparable with those of specimens dosed with cadmium or inhabiting contaminated areas in previous studies. Wood Ducks utilizing wetlands associated with the Illinois River, and presumably other portions of the lower Great Lakes region, may be chronically exposed to cadmium.