Embryonic Fundulus heteroclitus responses to sediment extracts from differentially contaminated sites in the Elizabeth River, VA.

Sites along the Elizabeth River are contaminated with polycyclic aromatic hydrocarbons (PAHs) from historical creosote production and other industrial processes. Previous studies have demonstrated that Atlantic killifish collected from sites throughout the Elizabeth River display resistance to the teratogenic effects of PAH-exposure in a manner commensurate with sediment PAH concentrations. The current study characterized various chemical pollutants in sediment and investigated the effects of aqueous sediment extracts from sites along the Elizabeth River to the cardiac development of Atlantic killifish embryos from fish collected from an uncontaminated reference site. Embryonic cardiac deformities were more prevalent after exposure to extracts from sites with high PAH loads. However, activation of cytochrome P4501A, a gene up-regulated by PAH-induction of the aryl hydrocarbon receptor and measured using an in ovo EROD assay, did not consistently increase with PAH concentrations. This work further characterizes sediments in the Elizabeth River, as well as provides insight into the evolutionary pressures at each ER site.

Integrating Monitoring and Genetic Methods To Infer Historical Risks of PCBs and DDE to Common and Roseate Terns Nesting Near the New Bedford Harbor Superfund Site (Massachusetts, USA).

Common and roseate terns are migratory piscivorous seabirds with major breeding colonies within feeding range of the polychlorinated biphenyl (PCB)-contaminated New Bedford Harbor (NBH, MA, USA) Superfund site. Our longitudinal study shows that before PCB discharges into NBH ceased (late 1970s), tern eggs had very high but variable PCB concentrations. However, egg concentrations of PCBs as well as DDE (1,1-bis(p-chlorophenyl)-2,2-dichloroethene), the degradation product of the ubiquitous global contaminant DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane), have since declined. Rate constants for temporal decline of PCB congeners in tern eggs varied inversely with log10KOW (n-octanol-water partition coefficient), shifting egg congener patterns away from those characterizing NBH sediment. To estimate the toxic effects on tern eggs of PCB dioxin-like congener (DLC) exposures, we extrapolated published laboratory data on common terns to roseate terns by characterizing genetic and functional similarities in species aryl hydrocarbon receptors (AHRs), which mediate DLC sensitivity. Our assessment of contaminant risks suggests that terns breeding near NBH were exposed historically to toxic levels of PCBs and DDE; however, acute effects on tern egg development have become less likely since the 1970s. Our approach demonstrates how comparative genetics at target loci can effectively increase the range of inference for chemical risk assessments from tested to untested and untestable species.

Approaches for predicting effects of unintended environmental exposure to an endocrine active pharmaceutical, tamoxifen.

Tamoxifen is an endocrine-active pharmaceutical (EAP) that is used world-wide. Because tamoxifen is a ubiquitous pharmaceutical and interacts with estrogen receptors, a case study was conducted with this compound to (1) determine effects on reproductive endpoints in a nontarget species (i.e., a fish), (2) compare biologically-active metabolites across species, (3) assess whether in vitro assays predict in vivo results, and (4) investigate metabolomic profiles in tamoxifen-treated fish to better understand the biological mechanisms of tamoxifen toxicity. In reproductive assays, tamoxifen exposure caused a significant reduction in egg production and significantly increased ovarian aromatase activity in spawning adult cunner fish (Tautogolabrus adspersus). In plasma from tamoxifen-exposed cunner, the predominant metabolite was 4-hydroxytamoxifen, while in rats it was N-desmethyltamoxifen. Because 4-hydroxytamoxifen is a more biologically active metabolite than N-desmethyltamoxifen, this difference could result in a different level of risk for the two species. The results of in vitro assays with fish hepatic microsomes to assess tamoxifen metabolism did not match in vivo results, indicating probable differences in excretion of tamoxifen metabolites in fish compared with rats. For the first time, a complete in vitro characterization of the metabolism of tamoxifen using fish microsomes is presented. Furthermore, a metabolomic investigation of cunner gonad extracts demonstrates that tamoxifen alters the biochemical profile in this nontarget species. Understanding the consequence of tamoxifen exposure in nontarget species, and assessing the discrepancies between sex- and species-mediated endpoints, is a step toward understanding how to accurately assess the risks posed by EAPs, such as tamoxifen, in the aquatic environment. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1834-1850, 2016.

Retrospective monitoring of persistent organic pollutants, including PCBs, PBDEs, and polycyclic musks in blue mussels (Mytilus edulis) and sediments from New Bedford Harbor, Massachusetts, USA: 1991-2005.

Blue mussels (Mytilus edulis) and sediments collected from 1991 to 2005 from New Bedford Harbor (NBH), MA, were analyzed for two polycyclic musks (HHCB or Galaxolide® and AHTN or Tonalide®), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs). HHCB and AHTN were found in mussel tissues at mean concentrations of 836 and 376 ng/g lipid weight (lw), respectively, which were two- to seven-fold higher than those found at a reference site. Mean concentrations of HHCB and AHTN in NBH sediments were 12 and 6.3 ng/g dry weight (dw), respectively. Four- and five-ringed PAHs, such as phenanthrene, anthracene, fluoranthene, and pyrene, collectively accounted for 61 % of the ∑PAHs concentrations in mussels from NBH. Mean ΣPCB concentrations in mussels from upper and lower NBH were 942 and 182 µg/g lw, respectively, and were dominated by tetra- and penta-chlorobiphenyl congeners, collectively accounting for 61 % of the ΣPCB concentrations. The mean concentration of ∑PBDEs in mussels from NBH was 277 ng/g lw, and no significant difference existed in the concentrations between upper and lower NBH. DDTs were the major OCP found in mussels, found at a mean concentration of 778 ng/g lw. The concentrations of HHCB, AHTN, ΣPBDEs, ΣPAHs, and DDTs in mussels decreased significantly (r (2) ≥ 0.56, p ≤ 0.052) from 1991 to 2005. The concentrations of PCBs and chlordanes did not exhibit a decreasing trend in mussel tissues (r (2) < 0.50; p > 0.076) from 1991 to 2005. Based on the temporal trends in the concentrations of HHCB, AHTN, ∑PAHs, and ∑PBDEs found in mussels from NBH, it was estimated that between 5.5 and 12 years were required for the concentrations of these compounds to decrease by half (i.e., environmental halving time) of the levels found in 1991.

Resistance to Cyp3a induction by polychlorinated biphenyls, including non-dioxin-like PCB153, in gills of killifish (Fundulus heteroclitus) from New Bedford Harbor.

Previous reports suggested that non-dioxin-like (NDL) PCB153 effects on cytochrome P450 3A (Cyp3a) expression in Atlantic killifish (Fundulus heteroclitus) gills differed between F0 generation fish from a PCB site (New Bedford Harbor; NBH) and a reference site (Scorton Creek; SC). Here, we examined effects of PCB153, dioxin-like (DL) PCB126, or a mixture of both, on Cyp3a56 mRNA in killifish generations removed from the wild, without environmental PCB exposures. PCB126 effects in liver and gills differed between populations, as expected. Gill Cyp3a56 was not affected by either congener in NBH F2 generation fish, but was induced by PCB153 in SC F1 fish, with females showing a greater response. PCB153 did not affect Cyp3a56 in liver of either population. Results suggest a heritable resistance to NDL-PCBs in killifish from NBH, in addition to that reported for DL PCBs. Induction of Cyp3a56 in gills may be a biomarker of exposure to NDL PCBs in fish populations that are not resistant to PCBs.

Bioaccumulation and effects of dietary exposure to the alternative flame retardant, bis(2-ethylhexyl) tetrabromophthalate (TBPH), in the Atlantic killifish, Fundulus heteroclitus.

Bis(2-ethylhexyl) tetrabromophthalate (TBPH), a high production volume flame retardant chemical used as a replacement for banned flame retardants, has been detected in media and human and wildlife tissues globally. We describe bioaccumulation and biological effects from dietary exposure of TBPH to an estuarine fish, Atlantic killifish, Fundulus heteroclitus. Briefly, adult fish were fed carrier control or chemically amended diets for 28 d, followed by 14 d of control diet feeding. Diets were amended with TBPH (TBPH_LO diet, 139 µg/g dry wt, or TBPH_HI diet, 4360 µg/g dry wt) or a polychlorinated biphenyl congener (PCB153 diet, 13 µg/g dry wt), which was included as a positive control for bioaccumulation. Although bioaccumulation of either chemical correlated with fish size, only a small proportion of the TBPH offered (<0.5% total TBPH) had bioaccumulated into TBPH-treated fish by 28 d. In contrast, 24.5% of the PCB153 offered was accounted for in 28-d PCB-treated fish. Although 28-d bioaccumulated concentrations of TBPH differed by sex and treatment, sexes did not differ in their rates of TBPH bioaccumulation, and the time to achieve 50% of 28 d concentration (T1/2 ) was estimated to be 13 d. Depuration rates of TBPH did not differ by sex or treatment, and the time after exposure to achieve T1/2 was estimated to be 22 d. Independent of treatment, male fish grew faster than female fish, but for both sexes reproductive condition (gonadal somatic index) declined unexpectedly over the experimental period. Across treatments, only the TBPH_LO treatment affected growth, reducing male but increasing female growth rates by small amounts relative to respective controls. In summary, our study used very high concentrations of dietary TBPH to contaminate fish tissues above the highest levels reported to date in wild biota, yet we observed few adverse biological effects. Environ Toxicol Chem 2018;37:2350-2360. © 2018 SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Nitrogen isotope ratios in estuarine biota collected along a nutrient gradient in Narragansett Bay, Rhode Island, USA.

Stable nitrogen isotope ratios were used to study the incorporation of anthropogenically-derived nitrogen into the food webs of salt marsh systems along a contamination gradient in Narragansett Bay. Nitrogen isotope ratios (delta(15)N) were measured in six estuarine species collected from three marshes along this gradient, monthly from June to October between 1997 and 1999. A significant decrease in delta(15)N was found with distance along the estuary for four of the six species. Significant differences were found among monthly isotope ratios for some species. Nitrogen isotope ratios in sea lettuce (Ulva lactuca) increased during the summer season with highest delta(15)N values measured during September and October. This trend was most pronounced at the station receiving the highest nutrient inputs. Elevated delta(15)N values at this station appeared to correlate with seawater ammonia/nitrate concentration ratios. The temporal variations in delta(15)N suggest that care should be taken in species selection and the design of sampling schemes of studies using delta(15)N for monitoring anthropogenic nutrients in aquatic systems. Sampling programs designed to determine long-term trends should consider species that do not show rapid fluctuations in isotope ratios. The mud snail, Nassarius obsoletus, responded this way in the present study. Studies designed to measure short-term changes should include species such as U. lactuca, which rapidly respond to isotope changes. The results from this study also help to establish a baseline for nitrogen isotope values in Narragansett Bay. This information can be used to monitor future trends in nitrogen inputs to this estuary.

Expression and function of ryanodine receptor related pathways in PCB tolerant Atlantic killifish (Fundulus heteroclitus) from New Bedford Harbor, MA, USA.

Atlantic killifish (Fundulus heteroclitus) thrive in New Bedford Harbor (NBH), MA, highly contaminated with polychlorinated biphenyls (PCBs). Resident killifish have evolved tolerance to dioxin-like (DL) PCBs, whose toxic effects through the aryl hydrocarbon receptor (AhR) are well studied. In NBH, non-dioxin like PCBs (NDL PCBs), which lack activity toward the AhR, vastly exceed levels of DL congeners yet how killifish counter NDL toxic effects has not been explored. In mammals and fish, NDL PCBs are potent activators of ryanodine receptors (RyR), Ca(2+) release channels necessary for a vast array of physiological processes. In the current study we compared the expression and function of RyR related pathways in NBH killifish with killifish from the reference site at Scorton Creek (SC, MA). Relative to the SC fish, adults from NBH displayed increased levels of skeletal muscle RyR1 protein, and increased levels of FK506-binding protein 12 kDa (FKBP12) an accessory protein essential for NDL PCB-triggered changes in RyR channel function. In accordance with increased RyR1 levels, NBH killifish displayed increased maximal ligand binding, increased maximal response to Ca(2+) activation and increased maximal response to activation by the NDL PCB congener PCB 95. Compared to SC, NBH embryos and larvae had increased levels of mtor and ryr2 transcripts at multiple stages of development, and generations, while levels of serca2 were decreased at 9 days post-fertilization in the F1 and F2 generations. These findings suggest that there are compensatory and heritable changes in RyR mediated Ca(2+) signaling proteins or potential signaling partners in NBH killifish.

Regulation of pregnane-X-receptor, CYP3A and P-glycoprotein genes in the PCB-resistant killifish (Fundulus heteroclitus) population from New Bedford Harbor.

Killifish survive and reproduce in the New Bedford Harbor (NBH) in Massachusetts (MA), USA, a site severely contaminated with polychlorinated biphenyls (PCBs) for decades. Levels of 22 different PCB congeners were analyzed in liver from killifish collected in 2008. Concentrations of dioxin-like PCBs in liver of NBH killifish were ∼400 times higher, and the levels of non-dioxin-like PCBs ∼3000 times higher than in killifish from a reference site, Scorton Creek (SC), MA. The NBH killifish are known to be resistant to the toxicity of dioxin-like compounds and to have a reduced aryl hydrocarbon receptor (AhR) signaling response. Little is known about the responses of these fish to non-dioxin-like PCBs, which are at extraordinarily high levels in NBH fish. In mammals, some non-dioxin-like PCB congeners act through nuclear receptor 1I2, the pregnane-X-receptor (PXR). To explore this pathway in killifish, a PXR cDNA was sequenced and its molecular phylogenetic relationship to other vertebrate PXRs was determined. Killifish were also collected in 2009 from NBH and SC, and after four months in the laboratory they were injected with a single dose of either the dioxin-like PCB 126 (an AhR agonist) or the non-dioxin-like PCB 153 (a mammalian PXR agonist). Gills and liver were sampled three days after injection and transcript levels of genes encoding PXR, cytochrome P450 3A (CYP3A), P-glycoprotein (Pgp), AhR2 and cytochrome P450 1A (CYP1A) were measured by quantitative PCR. As expected, there was little effect of PCB exposure on mRNA expression of AhR2 or CYP1A in liver and gills of NBH fish. In NBH fish, but not in SC fish, there was increased mRNA expression of hepatic PXR, CYP3A and Pgp upon exposure to either of the two PCB congeners. However, basal PXR and Pgp mRNA levels in liver of NBH fish were significantly lower than in SC fish. A different pattern was seen in gills, where there were no differences in basal mRNA expression of these genes between the two populations. In SC fish, but not in NBH fish, there was increased mRNA expression of branchial PXR and CYP3A upon exposure to PCB126 and of CYP3A upon exposure to PCB153. The results suggest a difference between the two populations in non-AhR transcription factor signaling in liver and gills, and that this could involve killifish PXR. It also implies possible cross-regulatory interactions between that factor (presumably PXR) and AhR2 in liver of these fish.

Environmental stress and recovery: the geochemical record of human disturbance in New Bedford Harbor and Apponagansett Bay, Massachusetts (USA).

Sediments record the history of contamination to estuaries. Analysis of the concentrations of toxic organic compounds, contaminant and crustal metals, organic carbon content and isotopic composition in sediment cores from two estuarine systems in Buzzards Bay allowed reconstruction of human impacts over 350 years. Vertical distributions of the contaminants correlate with changes in the nature of watershed/estuarine activities. All contaminants were highly enriched (tens to hundreds times background) in modern New Bedford Harbor sediments. Enrichment began around the turn of the 20th century for all but PCBs, which were first synthesized in the 1930s. An increase in organic carbon content and a shift of carbon isotopes toward a more terrestrial signature illustrates increasing anthropogenic impact in New Bedford as population grew along with the industrial base. Institution of environmental protection measures in the late 20th century was reflected in decreased, although still substantially elevated, concentrations of contaminants. A lack of industrial development in Apponagansett Bay resulted in much lower concentrations of the same indicators, although specific contaminants related to the early whaling industry increased significantly above background as early as the late 18th century. The similarity of indicators in older portions of cores from NBH and unimpacted Apponagansett Bay demonstrates that cores can be used to establish reference conditions as successfully as using separate sites judged a priori to represent the reference state. The historical reconstruction approach provides the basis for establishing relationships between environmental stressors and factors that drive the stressors, as well as a framework for the assessment of ecological response(s) to environmental stressors over a range of time and/or exposure scales.

Predicting the occurrence of genetic adaptation to dioxinlike compounds in populations of the estuarine fish Fundulus heteroclitus.

A population of the nonmigratory estuarine fish species Fundulus heteroclitus (mummichog) indigenous to a polychlorinated biphenyl (PCB)-contaminated Superfund site (New Bedford Harbor, MA, USA) demonstrated an inherited tolerance to local, dioxinlike contaminants (DLCs). These findings suggest that DLCs have acted as selective agents, allowing the survival of only the most tolerant individuals, forming DLC-adapted populations. We hypothesized that DLC-tolerant mummichog populations would reside where local conditions are toxic to sensitive individuals, and that toxic environmental conditions could be predicted based on responses of sensitive early life stages to laboratory exposures of DLCs. As a measure of DLC tolerance, progeny of field-collected fish were tested in the laboratory with a dioxinlike PCB congener, 3,3',4,4',5-pentachlorobiphenyl (PCB 126). Mummichog populations were collected from sites with sediment PCB concentrations predicted to range from nontoxic to toxic. Consistent with predictions, tolerant populations were indigenous to sites with elevated sediment PCB concentrations. Also, as predicted, DLC-tolerant populations were resident to sites far less contaminated than the Superfund site. These results suggest that exposures to persistent, bioaccumulative, and toxic contaminants may produce evolutionary effects on a geographic scale larger than previously envisioned. This study presents an approach and describes a model system that may improve understanding of the scale of occurrence for these potentially irreversible ecological effects.

Novel molecular events associated with altered steroidogenesis induced by exposure to atrazine in the intact and castrate male rat.

Toxicology is increasingly focused on molecular events comprising adverse outcome pathways. Atrazine activates the hypothalamic-pituitary adrenal axis, but relationships to gonadal alterations are unknown. We characterized hormone profiles and adrenal (intact and castrate) and testis (intact) proteomes in rats after 3 days of exposure. The adrenal accounted for most of the serum progesterone and all of the corticosterone increases in intact and castrated males. Serum luteinizing hormone, androstenedione, and testosterone in intact males shared a non-monotonic response suggesting transition from an acute stimulatory to a latent inhibitory response to exposure. Eight adrenal proteins were significantly altered with dose. There were unique proteomic changes between the adrenals of intact and castrated males. Six testis proteins in intact males had non-monotonic responses that significantly correlated with serum testosterone. Different dose-response curves for steroids and proteins in the adrenal and testis reveal novel adverse outcome pathways in intact and castrated male rats.

High performance liquid chromatographic analysis of phytoplankton pigments using a C16-amide column.

In this study, a reverse-phase HPLC method incorporating a ternary solvent system was developed to analyze most polar and non-polar chlorophylls and carotenoids present in phytoplankton. The method is based on an RP-C16-Amide column and provided excellent peak resolution of most taxonomically important pigments and an elution profile different than C8 or C18 columns provide. Analysis of mixed pigment standards, extracts of phytoplankton monocultures, and field samples showed that this method was able to resolve more than sixty pigments, ranging from very polar acidic chlorophylls to the non-polar hydrocarbon carotenes in less than 36 min. This included chlorophylls c1, c2 and c3, divinyl chlorophylls a and b, the carotenoids lutein and zeaxanthin and some recently discovered pigments. The ability of this method to resolve divinyl chl b from monovinyl chl b and divinyl chl a from monovinyl chl a is particularly important for the quantification and identification of the marine cyanobacteria Prochlorococcus spp. in oceanic waters. The described protocol is sensitive and reproducible and can be used to assess the distribution and dynamics of major phytoplankton groups in marine and freshwater ecosystems.

Evolution of tolerance to PCBs and susceptibility to a bacterial pathogen (Vibrio harveyi) in Atlantic killifish (Fundulus heteroclitus) from New Bedford (MA, USA) harbor.

A population of the non-migratory estuarine fish Fundulus heteroclitus (Atlantic killifish) resident to New Bedford (NB), Massachusetts, USA, an urban harbor highly contaminated with polychlorinated biphenyls (PCBs), demonstrates recently evolved tolerance to some aspects of PCB toxicity. PCB toxicology, ecological theory, and some precedence supported expectations of increased susceptibility to pathogens in NB killifish. However, laboratory bacterial challenges of the marine pathogen Vibrio harveyi to wild fish throughout the reproductive season and to their mature laboratory-raised progeny demonstrated comparable survival by NB and reference killifish, and improved survival by NB males. These results are inconsistent with hypothesized trade-offs of adaptation, and suggest that evolved tolerance in NB killifish may include mechanisms that minimize the immunosuppressive effects of PCBs. Compensatory strategies of populations persisting in highly contaminated environments provide a unique perspective for understanding the long-term ecological effects of toxic chemicals.

Characterization of the hypothalamic-pituitary-adrenal axis response to atrazine and metabolites in the female rat.

Atrazine (ATR) has recently been shown to activate the hypothalamic-pituitary-adrenal (HPA) axis in rodents. The current study investigated the effect of ATR and two of its chlorinated metabolites, desisopropylatrazine (DIA) and diamino-s-chlorotriazine (DACT), on the HPA axis in the Long-Evans female rat. A single oral gavage administration of 75 mg/kg ATR or 60.2 mg/kg DIA (a dose equimolar to the applied ATR dose) during the morning of proestrus resulted in significant, acute increases in circulating adrenocorticotropic hormone (ACTH), corticosterone, and progesterone. Oral doses of ATR or DIA were given daily over the course of the 4-day ovarian cycle starting on the day of vaginal estrus, resulted in a similar, dose-responsive activation of the HPA axis. The increase in ACTH, corticosterone, and progesterone by these compounds was of a similar magnitude to that produced by 5-min restraint stress. Single or multiple oral exposures to DACT, on the other hand, did not significantly alter pituitary-adrenal hormone release. These results were observed despite plasma levels of DACT being higher than any other metabolite at the time of hormone measurement. Overall, circulating metabolite concentrations following equimolar dosing were much higher than those observed after ATR administration. Additional studies indicated that the activation of the HPA axis by oral exposure to ATR and DIA was not due simply to the stimulation of gastrointestinal afferents. Similar responses were observed in rats which received an oral dose of ATR following bilateral subdiaphramatic vagotomy and following intravenous administration of DIA in jugular vein catheterized animals. We conclude that ATR and the metabolite DIA significantly activate the HPA axis following oral exposure in the female rat. Activation of this endocrine axis by these chlorotriazines could contribute to the induced changes of female reproductive function reported previously.

Chlorotriazine herbicides and metabolites activate an ACTH-dependent release of corticosterone in male Wistar rats.

Previously, we reported that atrazine (ATR) alters steroidogenesis in male Wistar rats resulting in elevated serum corticosterone (CORT), progesterone, and estrogens. The increase in CORT indicated that this chlorotriazine herbicide may alter the hypothalamic-pituitary-adrenal axis. This study characterizes the temporal changes in adrenocorticotropic hormone (ACTH), CORT, and P4 in male Wistar rats following a single dose of ATR (0, 5, 50, 100, and 200 mg/kg), simazine (SIM; 188 mg/kg), propazine (PRO; 213 mg/kg), or primary metabolites, deisopropylatrazine (DIA; 4, 10, 40, 80, and 160 mg/kg), deethylatrazine (DEA; 173 mg/kg), and diamino-s-chlorotriazine (DACT; 3.37, 33.7, 67.5, and 135 mg/kg). The maximum dose for each chemical was the molar equivalent of ATR (200 mg/kg). Significant increases in plasma ACTH were observed within 15 min, following exposure to ATR, SIM, PRO, DIA, or DEA. Dose-dependent elevations in CORT and progesterone were also observed at 15 and 30 min post-dosing with these compounds indicating an activation of adrenal steroidogenesis. Measurement of the plasma concentrations of the parent compounds and metabolites confirmed that ATR, SIM, and PRO are rapidly metabolized to DACT. Although DACT had only minimal effects on ACTH and steroid release, dosing with this metabolite resulted in plasma DACT concentrations that were 60-fold greater than that observed following an equimolar dose of ATR and eightfold greater than equimolar doses of DIA or DEA, indicating that DACT is not likely the primary inducer of ACTH release. Thus, the rapid release of ACTH and subsequent activation of adrenal steroidogenesis following a single exposure to ATR, SIM, PRO, DIA, or DEA may reflect chlorotriazine-induced changes at the level of the brain and/or pituitary.

PCBs and DDE in tree swallow (Tachycineta bicolor) eggs and nestlings from an estuarine PCB superfund site, New Bedford Harbor, MA, U.S.A.

While breeding tree swallows (Tachycineta bicolor) have been used as biomonitors for freshwater sites, we report the first use of this species to assess contaminant bioaccumulation from estuarine breeding grounds into these aerial insectivores. Eggs and nestlings were collected from nest boxes in a polychlorinated biphenyl (PCB) contaminated estuary, the New Bedford Harbor Superfund site (NBH, Massachusetts, USA), and a reference salt marsh, Fox Hill (FH, Jamestown, Rhode Island, USA). Sediments, eggs, and nestlings were compared on a ng g(-1) wet weight basis for total PCBs and DDE (1,1-bis-(4-chlorophenyl)-2,2-dichloroethene), metabolite of DDT (1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane). NBH samples contained high concentrations of PCBs compared to FH for sediment (36,500 and 0.2), eggs (11,200 and 323), and nestlings (16,800 and 26). PCB homologue patterns linked tree swallow contamination to NBH sediment. NBH samples were also contaminated with DDE compared to FH for sediment (207 and 0.9) and nestlings (235 and 30) but not for eggs (526 and 488), suggesting both NBH and nonbreeding ground sources for DDE. The relationships between sediment and tree swallow egg and nestling PCBs were similar to those reported for freshwater sites. Like some highly contaminated freshwater sites, NBH PCB bioaccumulation had little apparent effect on reproductive success.

The influence of suburban land use on habitat and biotic integrity of coastal Rhode Island streams.

Watershed land use in suburban areas can affect stream biota through degradation of instream habitat, water quality, and riparian vegetation. By monitoring stream biotic communities in various geographic regions, we can better understand and conserve our watershed ecosystems. The objective of this study was to examine the relationship between watershed land use and the integrity of benthic invertebrate communities in eight streams that were assessed over a 3-year period (2001-2003). Sites were selected from coastal Rhode Island watersheds along a residential land-use gradient (4-59%). Using the rapid bioassessment protocol, we collected biological, physicochemical, habitat, and nutrient data from wadeable stream reaches and compared metrics of structure and integrity. Principal component analyses showed significant negative correlation of indicators for stream physicochemical, habitat, and instream biodiversity with increasing residential land use (RLU) in the watershed. The physicochemical variables that were most responsive to percent RLU were conductivity, instream habitat, nitrate, and dissolved inorganic nitrogen (DIN). The positive correlation of DIN with percent RLU indicated an anthropogenic source of pollution affecting the streams. The biotic composition of the streams shifted from sensitive to insensitive taxa as percent RLU increased; the most responsive biological variables were percent Ephemeroptera, percent Scrapers, percent Insects, and the Hilsenhoff biotic index. These data show the importance of land management and conservation at the watershed scale to sustaining the biotic integrity of coastal stream ecosystems.

Environmental monitoring of remedial dredging at the New Bedford Harbor, MA, Superfund site.

New Bedford Harbor (NBH), MA, is a Superfund site because of high polychlorinated biphenyl (PCB) concentrations in the sediment. From April 1994 to September 1995, a remedial dredging operation (termed the "Hot Spot") removed the most contaminated sediments (PCB concentrations greater than 4000 microg/g) from the upper harbor. During remediation, a monitoring program assessed the potential environmental impacts to NBH and adjacent Buzzards Bay. The monitoring program was developed with input from federal, state, and local authorities. Site-specific decision criteria were established to assess net PCB transport, water column toxicity, and PCB bioaccumulation in blue and ribbed mussels (Mytilus edulis and Geukensia demissa, respectively). The remediation was completed without exceeding PCB net transport or acute toxicity effects specified in the decision criteria. In addition, PCB bioaccumulation in mussels during this time period was not significantly greater than pre- or post-operational measurements. The results indicated that approximately 14000 cubic yards of highly PCB contaminated sediment were permanently removed with minimal environmental effects. The lessons learned during this operation, as well as previous pilot studies at the site, will be used to make full-scale remedial efforts in NBH more efficient and environmentally protective.