Adria A. Elskus

LETHAL AND SUBLETHAL EFFECTS OF ATRAZINE, CARBARYL, ENDOSULFAN, AND OCTYLPHENOL ON THE STREAMSIDE SALAMANDER (AMBYSTOMA BARBOURI )

Agricultural contaminants may be contributing to worldwide amphibian declines, but little is known about which agrichemicals pose the greatest threat to particular species. One reason for this is that tests of multiple contaminants under ecologically relevant conditions are rarely conducted concurrently. In this study, we examined the effects of 37-d exposure to the agrichemicals atrazine (4, 40, and 400 micrograms/L), carbaryl (0.5, 5, and 50 micrograms/L), endosulfan (0.1, 1, and 10 micrograms/L for 31 d and 0.1, 10, and 100 micrograms/L for the last 6 d), and octylphenol (5, 50, and 500 micrograms/L) and to a solvent control on streamside salamanders (Ambystoma barbouri) in the presence and absence of food. We found that none of the agrichemicals significantly affected embryo survival, but that hatching was delayed by the highest concentration of octylphenol. In contrast to embryos, larval survival was reduced by the highest concentrations of carbaryl, endosulfan, and octylphenol. Growth rates were lower in the highest concentrations of endosulfan and octylphenol than in all other treatments, and the highest concentration of endosulfan caused respiratory distress. Significantly more carbaryl, endosulfan, and octylphenol tanks had larvae with limb deformities than did control tanks. Refuge use was independent of chemical exposure, but 10 micrograms/L of endosulfan and 500 micrograms/L of octylphenol decreased larval activity. Systematically tapping tanks caused a greater activity increase in larvae exposed to 400 micrograms/L of atrazine and 10 micrograms/L of endosulfan relative to solvent controls, suggesting underlying nervous system malfunction. Hunger stimulated a decrease in refuge use and an increase in activity, but this response was least pronounced in larvae exposed to the highest concentration of any of the four agrichemicals, possibly because these larvae were the most lethargic. More studies are needed that concurrently examine the effect of multiple contaminants on amphibians so we can better identify effective mitigating measures.

MULTIPLE STRESSORS AND SALAMANDERS: EFFECTS OF AN HERBICIDE, FOOD LIMITATION, AND HYDROPERIOD

Amphibian populations can be affected adversely by multiple biotic and abiotic stressors that together can contribute to their local and global decline. We focused on the combined effects of food limitation, drying conditions, and exposure to possibly the most abundant and widely used herbicide in the world, atrazine. We used a factorial design to evaluate the effects of exposure to four ecologically relevant doses of atrazine (approximate measured doses: 0, 4, 40, and 400 μg/L), two food levels (limited and unlimited food), and two hydroperiods (presence or absence of a dry down) on the survival, life history, and behavior of the streamside salamander, Ambystoma barbouri, from the embryo stage through metamorphosis. In general, food and atrazine levels did not interact statistically, and atrazine affected dependent variables in a standard, dose-dependent manner. Exposure to 400 μg/L of atrazine decreased embryo survival and increased time to hatching. Drying conditions and food limitation decreased larva...

Estrogenic responses of larval sunshine bass (Morone saxatilis × M. Chrysops) exposed to New York city sewage effluent

To determine the estrogenicity of effluents from sewage treatment plants (STPs) to larval fish, 2-day-old sunshine bass were exposed to effluents from three STPs serving New York City (NYC), varying in size and treatment level. Estrogenic response was evaluated by measuring vitellogenin (VTG) and estrogen receptor (ER) expression in cytosolic fractions of whole body homogenates. Concentrations of the presumptive endocrine disruptors in the effluents were also measured. VTG and ER levels in sewage-exposed fish were 3-5 times that observed in controls. Combined concentrations of estradiol and estrone ranged from 5 to 13 ng/l and nonylphenol-ethoxylate metabolites (NPEOs: 4-nonylphenol, and 1-, 2-, and 3-nonylphenol-ethoxylates) ranged from 180 to 470 microg/l in chlorinated effluent. Results indicate that both ER and VTG can be used as biomarkers for endocrine disruption in larval fish, and that 4-day exposure to sewage effluent is sufficient to elicit significant expression of these markers in sunshine bass larvae. The extremely higher concentrations of NPEOs found in effluent relative to hormones (approximately 40,000-fold) indicates that surfactant metabolites may be contributing significantly to the estrogenic effects observed.

Enzymatic and estrogenic responses in fish exposed to organic pollutants in the New York‐New Jersey (USA) Harbor Complex

This study examines biochemical and hormonal responses in resident and migratory fish from the New York-New Jersey (USA) Harbor Complex (NY-NJHC) and those treated with sediment-associated organic contaminants. Following laboratory exposures to organic extracts of NY-NJHC sediments (injection), livers from adult male mummichogs, Fundulus heteroclitus, were analyzed for vitellogenin (VTG), cytochrome P4501A (CYPIA), CYP3A, and estradiol 2-hydroxylase (E2OHase) and ethoxyresorufin-O-deethylase (EROD) activities. Levels of CYP1A (311-391% of control) and EROD (267-361% of control) were elevated in mummichogs exposed to high doses of sediment extracts, while VTG, CYP3A, and E2OHase were unaffected. In field studies, reproductively mature male mummichogs collected from a highly contaminated area, Newark Bay (NJ, USA), did not have detectable levels of VTG but did exhibit elevated levels of CYP1A and EROD. Vitellogenin was also not detected in juvenile striped bass (Morone saxatilis) collected from the main stem of the lower Hudson River (NY, USA). Similar to results in the sediment extract-treated fish. CYP3A and E2OHase were unaltered in Newark Bay F. heteroclitus. The lack of response of CYP3A and E2OHase activities to contaminant mixtures, either environment or sediment derived, suggests that compounds in these mixtures either do not alter these enzymes, produce antagonistic effects in mixtures, are present at ineffective concentrations, or are regulated in a species-specific manner.

Spatial Variation in Polycyclic Aromatic Hydrocarbon Concentrations in Eggs of Diamondback Terrapins, Malaclemys terrapin, from the Patuxent River, Maryland

Aquatic organisms encounter a number of contaminants in their environments. Here, we report polycyclic aromatic hydrocarbon (PAH) concentrations detected in diamondback terrapin eggs collected from the Patuxent River, Maryland, one year after an oil spill. Data suggested a geographic difference in egg hydrocarbon concentrations. However, at one year after the oil spill, most PAH concentrations detected were low, were not correlated with the extent of shoreline oiling, and thus likely represent current background levels. Future research should investigate the route of egg PAH exposure and include studies of embryotoxicity.

Effects of two fungicide formulations on microbial and macroinvertebrate leaf decomposition under laboratory conditions

Aquatic fungi contribute significantly to the decomposition of leaves in streams, a key ecosystem service. Little is known, however, about the effects of fungicides on aquatic fungi and macroinvertebrates involved with leaf decomposition. Red maple (Acer rubrum) leaves were conditioned in a stream to acquire microbes (bacteria and fungi) or leached in tap water (unconditioned) to simulate potential reduction of microbial biomass by fungicides. Conditioned leaves were exposed to fungicide formulations QUILT (azoxystrobin + propiconazole) or PRISTINE (boscalid + pyraclostrobin) in the presence and absence of the leaf shredder, Hyalella azteca (amphipods; 7-d old at start of exposures) for 14 d at 23 °C. The QUILT formulations (∼0.3 μg/L, 1.8 μg/L, and 8 μg/L) tended to increase leaf decomposition by amphipods (not significant) without a concomitant increase in amphipod biomass, indicating potential increased consumption of leaves with reduced nutritional value. The PRISTINE formulation (∼33 μg/L) significantly reduced amphipod growth and biomass (p < 0.05), effects similar to those observed with unconditioned controls. The significant suppressive effects of PRISTINE on amphipod growth and the trend toward increased leaf decomposition with increasing QUILT concentration indicate the potential for altered leaf decay in streams exposed to fungicides. Further work is needed to evaluate fungicide effects on leaf decomposition under conditions relevant to stream ecosystems, including temperature shifts and pulsed exposures to pesticide mixtures. Environ Toxicol Chem 2016;35:2834-2844. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.