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At least 73 records · Page 4Linked to original sources
USGS2007

Reproductive responses of male fathead minnows exposed to wastewater treatment plant effluent, effluent treated with XAD8 resin, and an environmentally relevant mixture of alkylphenol compounds

On-site, continuous-flow experiments were conducted during August and October 2002 at a major metropolitan wastewater treatment plant (WWTP) to determine if effluent exposure induced endocrine disruption as manifested in the reproductive competence of sexually mature male fathead minnows ( Pimephales promelas ). The fathead minnows were exposed in parallel experiments to WWTP effluent and WWTP effluent treated with XAD8 macroreticular resin to remove the hydrophobic-neutral fraction which contained steroidal hormones, alkylphenolethoxylates (APEs), and other potential endocrine disrupting compounds (EDCs). The effluent composition varied on a temporal scale and the continuous-flow experiments captured the range of chemical variability that occurred during normal WWTP operations. Exposure to WWTP effluent resulted in vitellogenin induction in male fathead minnows, with greater response in October than in August. Concentrations of ammonia, APEs, 17β-estradiol, and other EDCs also were greater in October than in August, reflecting a change in effluent composition. In the October experiment, XAD8 treatment significantly reduced vitellogenin induction in the male fathead minnows relative to the untreated effluent, whereas in August, XAD8 treatment had little effect. During both experiments, XAD8 treatment removed greater than 90% of the APEs. Exposure of fish to a mixture of APEs similar in composition and concentration to the WWTP effluent, but prepared in groundwater and conducted at a separate facility, elicited vitellogenin induction during both experiments. There was a positive relation between vitellogenin induction and hepatosomatic index (HSI), but not gonadosomatic index (GSI), secondary sexual characteristics index (SSCI), or reproductive competency. In contrast to expectations, the GSI and SSCI increased in males exposed to WWTP effluent compared to groundwater controls. The GSI, SSCI, and reproductive competency were positively affected by XAD8 treatment of the WWTP effluent.

Aquatic Toxicology↗
USGS2026

Polychlorinated biphenyl (PCB) exposure assessment of Carolina wren (Thryothorus ludovicianus) and barn swallow (Hirundo rustica) eggs and nestlings collected along Snow Creek and Choccolocco Creek watersheds near Anniston, Alabama, USA

Polychlorinated biphenyls (PCBs) persist for decades when released into the environment and bioaccumulate in aquatic and terrestrial environments, resulting in harmful concentrations of PCBs in fishes, birds, and humans. Approximately 310,000 metric tons of PCBs were produced at a facility in Anniston, Alabama from 1929–1971. Hundreds of metric tons of PCB-contaminated waste were suspected to have been released into local environments. This study was the first systematic exposure assessment of the degree and extent of PCBs and potential co-contaminants—polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, Pb, and Hg—in avian tissues downstream of the Anniston facility. We collected 122 egg and 36 nestling tissue samples from across four exposure areas downstream of the facility and a reference site. A total of seven bird species were collected, but samples were predominantly Carolina wren (resident, Thryothorus ludovicianus ) and barn swallow (migratory, Hirundo rustica ). Concentrations of Pb and Hg in bird tissues collected from the exposure areas were less than toxicity reference values, suggesting Pb or Hg exposures alone were unlikely to affect birds. Total PCB concentrations in avian eggs and nestlings collected from exposure areas were among the greatest ever recorded in birds collected in North America. The PCB congener profiles in this study, paired with results from previous soil and sediment sampling, suggest that PCB-contaminated sediment and soil were the likely source of elevated PCBs in the avian tissues. The PCB concentrations observed in birds downstream of the Anniston facility were at magnitudes that likely affect populations of both resident and migratory birds that utilize the area for foraging and reproduction.

Alabama↗
USGS1999

Organochlorine contaminants and reproductive success of double-crested cormorants from Green Bay, Wisconsin, USA

In 1994 and 1995, nesting success of double-crested cormorants ( Phalacrocorax auritus ) was measured at Cat Island, in southern Green Bay, Lake Michigan, Wisconsin, USA. Sample eggs at pipping and unhatched eggs were collected and analyzed for organochlorines (including total polychlorinated biphenyls [PCBs] and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in embryos, and eggshell thickness. Of 1,570 eggs laid, 32% did not hatch and 0.4% had deformed embryos. Of 632 chicks monitored from hatching to 12 d of age, 9% were missing or found dead; no deformities were observed. The PCB concentrations in sample eggs from clutches with deformed embryos (mean = 10.2 μg/g wet weight) and dead embryos (11.4 μg/g) were not significantly higher than concentrations in sample eggs from nests where all eggs hatched (12.1 μg/g). A logistic regression of hatching success versus DDE, dieldrin, and PCB concentrations in sibling eggs identified DDE and not dieldrin or PCBs as a significant risk factor. A logistic regression of hatching success versus DDE and eggshell thickness implicated DDE and not eggshell thickness as a significant risk factor. Even though the insecticide DDT was banned in the early 1970s, we suggest that DDE concentrations in double-crested cormorant eggs in Green Bay are still having an effect on reproduction in this species.

Wisconsin↗
USGS1986

Selenium and heavy metals in San Francisco Bay diving ducks

We analyzed for selenium (Se) and heavy metals in greater scaups ( Aythya marila ) and surf scoters ( Melanitta perspicillata ) collected from southern San Francisco Bay in March and April 1982. There were no differences (P > 0.05) between species for liver concentrations of silver (Ag), mercury (Hg), or lead (Pb). Copper (Cu) (P < 0.001) and zinc (Zn) (P < 0.01) levels were higher in scaups, whereas Se was higher in scoters (P < 0.001). Chromium (Cr) and nickel (Ni) occurred in < 50% of the samples, and there was no difference (P > 0.05) between the 2 species. The geometric mean cadmium (Cd) concentration in scoter kidneys (24.6 ppm, dry wt) was higher than in scaups (15.5 ppm) (0.1 > P > 0.05). Liver concentrations of Hg and Se were correlated (P < 0.01). The toxicological significance of some elements in these species is not known. However, Se levels in scoters (34.4 ppm, dry wt) were similar to those in livers of dabbling ducks (Anas spp.) in the nearby San Joaquin Valley where reproduction was impaired severely.

California↗
USGS1994

Contaminants in eggs of aquatic birds from the grasslands of central California

Eggs were collected from the Grasslands of western Merced County, California, during 1986 and 1987, and at the Mendota Wildlife Area in Fresno County in 1987, as part of a reproductive study of nesting ducks and shorebirds. The eggs were analyzed to evaluate the effects of contaminants in agricultural drainwater on avian reproduction. Agricultural drainwater was the major source of water for irrigation and fall flooding in the Grasslands until the fall of 1985 when drainwater was mostly replaced by uncontaminated water. Drainwater had not been used at Mendota. Concentrations of arsenic and boron in eggs from all sites were lower than those known to harm avian reproduction. However, mean concentrations of selenium, a trace element known to impair avian reproduction at high dietary levels, were higher in eggs from the Grasslands than in eggs from the uncontaminated site. Although some selenium concentrations were as high as those found to have caused death or deformities at other sites, reproductive impairment was not observed in any ducks or shorebirds nesting in the Grasslands in 1986 or 1987.

California↗
USGS2019

Perfluoroalkyl contaminant exposure in tree swallows nesting at Clarks Marsh, Oscoda, Michigan, USA

A site in north eastern Michigan, Oscoda Township, has some of the highest recorded exposure in birds to perfluorinated substances (PFASs) in the U.S. Some egg and plasma concentrations at that location exceeded the lowest reproductive effect threshold established for two avian laboratory species. The objectives of this study were to determine whether there were reproductive effects or physiological responses in a model bird species, the tree swallow (Tachycineta bicolor), associated with this extremely high exposure to PFASs. The lack of exposure above background to other contaminants at this site allowed for an assessment of PFAS effects without the complication that responses may be caused by other contaminants. A secondary objective was to determine the distribution of PFASs in multiple tissue types to better understand and interpret residues in different tissues. This can best be done at highly exposed locations where tissue concentrations would be expected to be above detectable levels if they are present in that tissue. There were no demonstrable effects of PFAS exposure on reproduction nor on most physiological responses.

Michigan↗
USGS2008

Use of a 15 k gene microarray to determine gene expression changes in response to acute and chronic methylmercury exposure in the fathead minnow Pimephales promelas Rafinesque

This study describes the use of a 15 000 gene microarray developed for the toxicological model species, Pimephales promelas, in investigating the impact of acute and chronic methylmercury exposures in male gonad and liver tissues. The results show significant differences in the individual genes that were differentially expressed in response to each treatment. In liver, a total of 650 genes exhibited significantly (P < 0.05) altered expression with greater than two-fold differences from the controls in response to acute exposure and a total of 267 genes were differentially expressed in response to chronic exposure. A majority of these genes were downregulated rather than upregulated. Fewer genes were altered in gonad than in liver at both timepoints. A total of 212 genes were differentially expressed in response to acute exposure and 155 genes were altered in response to chronic exposure. Despite the differences in individual genes expressed across treatments, the functional categories that altered genes were associated with showed some similarities. Of interest in light of other studies involving the effects of methylmercury on fish, several genes associated with apoptosis were upregulated in response to both acute and chronic exposures. Induction of apoptosis has been associated with effects on reproduction seen in the previous studies. This study demonstrates the utility of microarray analysis for investigations of the physiological effects of toxicants as well as the time-course of effects that may take place. In addition, it is the first publication to demonstrate the use of this new 15 000 gene microarray for fish biology and toxicology. ?? 2008 The Authors.

Journal of Fish Biology↗
USGS1994

Main and interactive effects of arsenic and selenium on mallard reproduction and duckling growth and survival

Arsenic (As) and selenium (Se) occur together in high concentrations in the environment and can accumulate in aquatic plants and invertebrates consumed by waterfowl. Ninety-nine pairs of breeding mallards ( Anas platyrhynchos ) were fed diets supplemented with As (sodium arsenate) at 0, 25, 100, or 400 μg/g, in combination with Se (seleno-DL-methionine) at 0 or 10 μg/g, in a replicated factorial experiment. Ducklings produced were placed on the same treatment combination as their parents. Arsenic accumulated in adult liver and egg, reduced adult weight gain and liver weight, delayed the onset of egg laying, decreased whole egg weight, and caused eggshell thinning. Arsenic did not affect hatching success and was not teratogenic. In ducklings, As accumulated in the liver and reduced body weight, growth, and liver weight. Arsenic did not increase duckling mortality, but it did decrease overall duckling production. Selenium accumulated in adult liver and egg, was teratogenic, and decreased hatching success. Selenium did not affect adult weight, liver weight, survival, onset of egg laying, egg fertility, egg weight, or eggshell thickness. In ducklings, Se accumulated in the liver and reduced body weight and growth, and increased liver weight. Selenium increased duckling mortality and decreased overall duckling production. Antagonistic interactions between As and Se occurred whereby As reduced Se accumulation in liver and egg, and alleviated the effects of Se on hatching success and embryo deformities. It was demonstrated that As and Se, in the chemical forms and at the dietary levels administered in this study, can adversely affect mallard reproduction and duckling growth and survival, and that As can alleviate toxic effects of Se.

Archives of Environmental Contamination and Toxico↗
USGS1983

Breeding success of barn owls (Tyto alba) fed low levels of DDE and dieldrin

The relative importance of two organochlorine pesticides in the recent reproductive failure of raptors was investigated. Captive barn owls were fed 3.0 ppm DDE and 0.5 ppm dieldrin; doses were given separately and in combination for two years. Breeding success was followed from the laying of eggs through natural incubation and rearing of young. DDE was associated with significant eggshell thinning, egg breakage, embryo mortality, and reduced production per pair. Dieldrin alone was associated with slight but significant eggshell thinning, but not with reduction of breeding success. Ecological implications of the results are discussed; it is suggested that DDE had a much more severe effect on reproduction in wild raptors than dieldrin, which contributed to their decline primarily through adult mortality.

Archives of Environmental Contamination and Toxico↗
USGS1990

Comparison of breaking strength and shell thickness as evaluators of white-faced ibis eggshell quality

Data from a 1986 field study of white-faced ibis ( Plegadis chihi ) nesting at Carson Lake, Nevada, were used to compare the utility of eggshell strength measurement and eggshell thickness as indicators of eggshell quality. The ibis population had a history of reproductive failure correlated with elevated egg concentrations of p, p '-DDE, hereafter referred to as DDE. Eggs from 80 nests (one egg/nest) were tested for shell strength and thickness. Egg contents were analyzed for organochlorines, mercury and selenium; productivity at each nest (minus one egg) was monitored in the field. DDE-DDT concentrations in the eggs ranged from none detected (<0.1) to 29 ppm (wet weight). Shell thickness and shell strength were both negatively correlated with DDE (−0.60, −0.61, respectively), but shell strength deteriorated at a faster rate than shell thickness. Scanning electron micrographs indicated the deterioration in strength was related to changes in ultrastructure as well as to decreased thickness. Fourteen eggs with <0.40 ppm DDE were used to exemplify normal “control” eggs. Of the eggs with higher concentrations of DDE (i.e., ≥0.40 ppm), 11 of 66 were thinner (>2 SD below “control” mean) than normal, 11 of 59 were weaker than normal and 7 eggs were cracked so their strength could not be tested, although thickness was measured. Therefore, 17% of the eggs with ≥0.40 ppm DDE were thinner than normal and 27% were either weaker than normal or cracked. Further, six eggs (four with ≥15 ppm DDE) did not have abnormally thin shells, but did have abnormally weak shells. Nests with abnormal test eggs (thinner, weaker or cracked) produced fewer young than nests with normal eggs. Use of the shell strength parameter provides additional information for better evaluations of reproductive problems. The potential utility of monitoring eggshell quality goes beyond evaluating effects of organochlorines since recent work indicates that other environmental hazards can affect shell quality.

Environmental Toxicology and Chemistry↗
USGS2009

Predator avoidance performance of larval fathead minnows (Pimephales promelas) following short-term exposure to estrogen mixtures

Aquatic organisms exposed to endocrine disrupting compounds (EDCs) at early life-stages may have reduced reproductive fitness via disruption of reproductive and non-reproductive behavioral and physiological pathways. Survival to reproductive age relies upon optimal non-reproductive trait expression, such as adequate predator avoidance responses, which may be impacted through EDC exposure. During a predator–prey confrontation, larval fish use an innate C-start escape behavior to rapidly move away from an approaching threat. We tested the hypotheses that (1) larval fathead minnows exposed to estro gens, a primary class of EDCs, singularly or in mixture, suffer a reduced ability to perform an innate C-start behavior when faced with a threat stimulus; (2) additive effects will cause greater reductions in C-start behavior; and (3) effects will differ among developmental stages. In this study, embryos (post-fertilization until hatching) were exposed for 5 days to environmentally relevant concentrations of estrone (E1), 17-estradiol (E2), and 17-ethinylestradiol (EE2) singularly and in mixture. Exposed embryos were allowed to hatch and grow in control well water until 12 days old. Similarly, post-hatch fathead minnows were exposed for 12 days to these compounds. High-speed (1000 frames/s) video recordings of escape behavior were collected and transferred to National Institutes of Health Image for frame-by-frame anal- ysis of latency period, escape velocity, and total escape response (combination of latency period and escape velocity). When tested 12 days post-hatch, only E1 adversely affected C-start performance of larvae exposed as embryos. Conversely, larvae exposed for 12 days post-hatch did not exhibit altered escape responses when exposed to E1, while adverse responses were seen in E2 and the estrogen mixture. Ethinylestradiol exposure did not elicit changes in escape behaviors at either developmental stage. The direct impact of reduced C-start performance on survival, and ultimately, reproductive fitness provides an avenue to assess the ecological relevance of exposure in an assay of relatively short duration.

Aquatic Toxicology↗
USGS2002

Effects of chronic dietary exposure to environmentally relevant concentrations to 2,3,7,8-tetrachlorodibenzo-p-dioxin on survival, growth, reproduction and biochemical responses of female rainbow trout (Oncorhynchus mykiss)

Adult female rainbow trout were exposed to dietary 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) at concentrations of 1.8, 18 and 90 ng TCDD/kg (ww) food for up to 300 day. At the end of the exposure fish were spawned and the reproductive outcomes were assessed. TCDD was accumulated into tissues and eggs in a dose-dependent manner with steady state being achieved after 50–100 day of exposure. Biochemical and hematological parameters were monitored at 50, 100, 150, and 200 day after the beginning of exposure. The survival of adult female trout was reduced in a dose-dependent manner by exposure to TCDD in the diet. Fish fed 1.8 ng TCDD/kg, moist weight of diet, showed significantly reduced survival compared with those fed the control diet. TCDD also affected survival of fry from females fed 1.8 ng TCDD/kg. Observed adverse effects in adult fish were as sensitive as early life-stage endpoints. Liver EROD activity was only moderately increased in all exposure groups after 250+ day of exposure. Low rates of edema and deformities were observed in fry from all treatment groups including controls. This study has demonstrated adverse effects of TCDD to both adults and fry at concentrations comparable to current environmental concentrations. This suggests that direct adult toxicity as well as reproductive endpoints need to be incorporated in the current risk assessment paradigm for these compounds.

Aquatic Toxicology↗
USGS2005

Changes in productivity and contaminants in bald eagles nesting along the lower Columbia River, USA

Previous studies documented poor productivity of bald eagles (Haliaeetus leucocephalus) in the lower Columbia River (LCR), USA, and elevated p,p???-dichlorodiphenyldichloroethylene (DDE), polychlorinated biphenyls (PCBs), dioxins, and furans in eagle eggs. From 1994 to 1995, we collected partially incubated eggs at 19 of 43 occupied territories along the LCR and compared productivity and egg contaminants to values obtained in the mid-1980s. We found higher productivity at new nesting sites along the river, yet productivity at 23 older breeding territories remained low and was not different (p = 0.713) between studies. Eggshell thickness at older territories had not improved (p = 0.404), and eggshells averaged 11% thinner than shells measured before dichlorodiphenyltrichloroethane use. Decreases in DDE (p = 0.022) and total PCBs (p = 0.0004) in eggs from older breeding areas occurred between study periods. Productivity was not correlated to contaminants, but DDE, PCBs, and dioxin-like chemicals exceeded estimated no-effect values. Some dioxin-like contaminants in eggs were correlated to nest location, with highest concentrations occurring toward the river's mouth where productivity was lowest. Although total productivity increased due to the success of new nesting pairs in the region, egg contaminants remain high enough to impair reproduction at older territories and, over time, may alter productivity of new pairs nesting near the river's mouth. ?? 2005 SETAC.

Oregon, Washington↗
USGS1987

Seasonal variation in diagnostic enzymes and biochemical constituents of captive northern bobwhites and passerines

1. A variety of biochemical measurements were taken periodically in captive northern bobwhite ( Colinus virginianus L.), European starlings ( Sturnus vulgaris L.), red-winged blackbirds ( Agelaius phoeniceus L.) and common grackles ( Quiscalus quiscula L.) to determine whether baseline values remain sufficiently stable throughout the year for general clinical use in the absence of concurrent control specimens. 2. Variables included whole blood hemotacrit and hemoglobin, plasma lactate dehydrogenase, α-hydroxybutyrate dehydrogenase, aspartate aminotransferase, alinine aminotransferase, creatine kinase, butyrylcholinesterase, alkaline phosphatase, glucose, albumin, total protein, creatinine, urea nitrogen, uric acid, cholesterol, and triglycerides, and brain acetylcholinesterase. Butyrl- and acetylcholinesterase were included because of their specific uses in toxicology. 3. Significant seasonal differences were detected for each of the variables except brain acetylcholinesterase in at least one of the species. Significant species differences were detected during at least one season for all of the variables measured. 4. All species were maintained outdoors, but only northern bobwhites came into reproductive condition and showed sex-differences in the clinical variables during their normal breeding season. 5. It was concluded that reference values for the 18 clinical variables measured could be calculated from our data for adult specimens of the species studied, and that results for one species cannot be extrapolated with certainty to any other species. 6. Estimated normal bounds for each of the 18 variables measured by commonly used clinical procedures are presented for reproductively quiescent northern bobwhites, European starlings, red-winged blackbirds, and common grackles.

Comparative Biochemistry and Physiology, Part B: C↗
USGS2011

Demasculinization of male fish by wastewater treatment plant effluent

Adult male fathead minnows ( Pimephales promelas ) were exposed to effluent from the City of Boulder, Colorado wastewater treatment plant (WWTP) under controlled conditions in the field to determine if the effluent induced reproductive disruption in fish. Gonadal intersex and other evidence of reproductive disruption were previously identified in white suckers ( Catostomus commersoni ) in Boulder Creek downstream from this WWTP effluent outfall. Fish were exposed within a mobile flow-through exposure laboratory in July 2005 and August 2006 to WWTP effluent (EFF), Boulder Creek water (REF), or mixtures of EFF and REF for up to 28 days. Primary (sperm abundance) and secondary (nuptial tubercles and dorsal fat pads) sex characteristics were demasculinized within 14 days of exposure to 50% and 100% EFF. Vitellogenin was maximally elevated in both 50% and 100% EFF treatments within 7 days and significantly elevated by 25% EFF within 14 days. The steroidal estrogens 17β-estradiol, estrone, estriol, and 17α-ethynylestradiol, as well as estrogenic alkylphenols and bisphenol A were identified within the EFF treatments and not in the REF treatment. These results support the hypothesis that the reproductive disruption observed in this watershed is due to endocrine-active chemicals in the WWTP effluent.

Colorado↗
USGS2008

Potential effects of mercury on threatened California black rails

San Francisco Bay (SFB) estuary sediments contain high levels of mercury (Hg), and tidal marsh resident species may be vulnerable to Hg contamination. We examined Hg concentrations in California black rails, a threatened waterbird species that inhabits SFB tidal salt marshes. We captured 127 black rails during the prebreeding and postbreeding seasons and examined the influence of site, sex, and year on Hg, methylmercury (MeHg), and also selenium (Se) concentrations in feathers and blood. Feather Hg concentrations averaged 6.94 ??g/g dry weight (dw) and MeHg and Se concentrations in blood averaged 0.38 and 0.42 ??g/g wet weight (ww). We used Akaike's information criterion model selection process to evaluate the importance of year, site, sex, and age on patterns of MeHg concentrations; sex and year were the most important of these factors. Feather Hg concentrations (dw) were higher in males (8.22 ??g/g) than females (6.63 ??g/g) and higher in adult birds (7.36 ??g/g) than in hatch-year birds (4.61 ??g/g). A substantial portion of SFB black rail populations may be at risk of reproductive effects due to MeHg contamination, as 32-78% of feathers and <10% of blood samples exceeded no observed adverse effect levels. Sea level rise and other anthropogenic threats to endemic tidal marsh species such as black rails may be exacerbated by the presence of MeHg. Further study of population demographics and toxicological effects would further elucidate the effects of MeHg contamination on black rail populations in SFB. ?? 2008 Springer Science+Business Media, LLC.

Archives of Environmental Contamination and Toxico↗
USGS1993

Acidic Depositions: Effects on Wildlife and Habitats

The phenomenon of 'acid rain' is not new; it was recognized in the mid-1800s in industrialized Europe. In the 1960s a synthesis of information about acidification began in Europe, along with predictions of ecological effects. In the U.S. studies of acidification began in the 1920s. By the late 1970s research efforts in the U.S. and Canada were better coordinated and in 1980 a 10-year research program was undertaken through the National Acid Precipitation Assessment Plan (NAPAP) to determine the causes and consequences of acidic depositions. Much of the bedrock in the northeastern U.S. and Canada contains total alkalinity of <200 ?eq 1-1, thus, it lacks acid-neutralizing capacity. In the U.S. about 5% of the land area and in Canada about 43 % of the land area is sensitive to acidic depositions. Further, these areas receive >20 kg/ha/yr of wet sulphate depositions and are vulnerable to acidifying processes. Acidic depositions contribute directly to acidifying processes of soil and soil water. Soils must have sufficient acid-neutralizing capacity or acidity of soil will increase. Natural soil-forming processes that lead to acidification can be accelerated by acidic depositions. Long-term effects of acidification are predicted, which will reduce soil productivity mainly through reduced availability of nutrients and mobilization of toxic metals. Severe effects may lead to major alteration of soil chemistry, soil biota, and even loss of vegetation. Several species of earthworms and several other taxa of soil-inhabiting invertebrates, which are important food of many vertebrate wildlife species, are affected by low pH in soil. Loss of canopy in declining sugar maples results in loss of insects fed on by certain neotropical migrant bird species. No definitive studies categorically link atmospheric acidic depositions with direct or indirect effects on wild mammals. Researchers have concentrated on vegetative and aquatic effects. Circumstantial evidence suggests that effects are probable for certain species of aquatic-dependent mammals (water shrew, mink, and otter) and that these species are at risk from the loss of foods or contamination of these foods by metals, especially methylmercury. Continued acidification of terrestrial habitats, to the extent that earthworm populations are broadly reduced, might expose some fossorial mammalian species to risk because of decline in their major prey species. Acidic deposition affects primarily aquatic habitats of avian species by disrupting food webs (ecological effects) and increasing amounts of available heavy metals (mercury, aluminum, cadmium) in prey of avian species (toxicological effects). The ecological effects of acidifying wetlands are to reduce acid-intolerant prey (invertebrates) and to change prey quality from high-calcium bearing prey to low-calcium bearing prey. The toxicological effects are to increase contamination by heavy metals, especially methylated mercury, in foods of breeding waterbirds. The combination of these 2 types of effects results in potentially lower survival of adults and reduced production, growth, or survival of young of many bird species. Effects of acidification on herpteofauna and their habitats are mainly reproductive failure of susceptible species and reduced or metal-contaminated foods for both amphibians and reptiles.

Wildlife Society Technical Review↗