EPA Superfund Site Research Articles

Influence of Metal Contamination and Sediment Deposition on Benthic Invertebrate Colonization at the North Fork Clear Creek Superfund Site, Colorado, USA.

Assessing benthic invertebrate community responses to multiple stressors is necessary to improve the success of restoration and biomonitoring projects. Results of mesocosm and field experiments were integrated to predict how benthic macroinvertebrate communities would recover following the removal of acid mine drainage from the North Fork of Clear Creek (NFCC), a U.S. EPA Superfund site in Colorado, USA. We transferred reference and metal-contaminated sediment to an upstream reference site where colonization by benthic macroinvertebrates was measured over 30 days. Additionally, a mesocosm experiment was performed to test the hypothesis that patches of metal-contaminated substrate impede recolonization downstream. Abundance in all treatments increased over time during field experiments; however, colonization was slower in treatments with metal-contaminated fine sediment. Community assemblages in treatments with metal-contaminated fine substrate were significantly different from other treatments. Patterns in the mesocosm study were consistent with results of the field experiment and showed greater separation in community structure between streams with metal-contaminated sediments and reference-coarse habitats; however, biological traits also helped explain downstream colonization. This study suggests that after water quality improvements at NFCC, fine-sediment deposition will likely reduce recovery potential for some taxa; however highly mobile taxa that avoid patches of contaminated habitats can recover quickly.

Variability in metagenomic samples from the Puget Sound: Relationship to temporal and anthropogenic impacts.

Whole-metagenome sequencing (WMS) has emerged as a powerful tool to assess potential public health risks in marine environments by measuring changes in microbial community structure and function in uncultured bacteria. In addition to monitoring public health risks such as antibiotic resistance determinants, it is essential to measure predictors of microbial variation in order to identify natural versus anthropogenic factors as well as to evaluate reproducibility of metagenomic measurements.This study expands our previous metagenomic characterization of Puget Sound by sampling new nearshore environments including the Duwamish River, an EPA superfund site, and the Hood Canal, an area characterized by highly variable oxygen levels. We also resampled a wastewater treatment plant, nearshore and open ocean sites introducing a longitudinal component measuring seasonal and locational variations and establishing metagenomics sampling reproducibility. Microbial composition from samples collected in the open sound were highly similar within the same season and location across different years, while nearshore samples revealed multi-fold seasonal variation in microbial composition and diversity. Comparisons with recently sequenced predominant marine bacterial genomes helped provide much greater species level taxonomic detail compared to our previous study. Antibiotic resistance determinants and pollution and detoxification indicators largely grouped by location showing minor seasonal differences. Metal resistance, oxidative stress and detoxification systems showed no increase in samples proximal to an EPA superfund site indicating a lack of ecosystem adaptation to anthropogenic impacts. Taxonomic analysis of common sewage influent families showed a surprising similarity between wastewater treatment plant and open sound samples suggesting a low-level but pervasive sewage influent signature in Puget Sound surface waters. Our study shows reproducibility of metagenomic data sampling in multiple Puget Sound locations while establishing baseline measurements of antibiotic resistance determinants, pollution and detoxification systems. Combining seasonal and longitudinal data across these locations provides a foundation for evaluating variation in future studies.

The river mouth speaks: water quality as storyteller in decolonization of the Port of Tacoma

In this paper, I describe historical geographies of settler colonization and decolonization in the Port of Tacoma, Washington tideflats using the lens of biological, habitat, flow, and physico-chemical indicators of water quality. The Puyallup River empties into what is now known as the Port of Tacoma. Before the Port’s industrialization, the tideflats and bay were rich with shellfish and anadromous fish, important traditional sources of food for the Puyallup Tribe of Indians. Colonization and allotment led to severe environmental degradation and removal of the tribe from their land. Because of waste dumped by settler colonial industry, the nearshore tideflats at the Puyallup River’s mouth are now an EPA Superfund site, containing phthalates, heavy metals, pesticides, PCBs, and more. Over the years of its industrialization, the river has been channelized and the shoreline armored. In addition, for many years the City of Tacoma dumped sewage directly into the Port waterways. In the 1950 and 1960s, the Puyallup Tribe participated in the Puget Sound “Fish Wars,” forcing attention to treaty rights through off-reservation fish-ins, and leading to the 1974 Boldt Decision upholding tribal treaty rights. With the legal recourse enabled by the Boldt Decision, the Puyallup Tribe successfully sued the Port, interstate, railroad companies, polluting industry, and several cities for occupied land denoted as theirs by the Treaty of Medicine Creek. In addition, the tribe has participated in several lawsuits forcing aquatic habitat restoration and remediation efforts along the river and tideflats. I describe colonial and decolonizing processes of shaping and re-shaping the river mouth, beginning in the late 1800s, and assess changes in water quality from the mid-1800s through present day using recent data on contaminants, as well as proxies of indicator species for unavailable data from earlier eras. I use these data to understand the ways the tribe’s legal challenges to colonization have impacted the area’s environmental health. I conclude that legal affirmations of tribal sovereignty are positively associated with estuarine ecosystem health.

A review of the Texas, USA San Jacinto Superfund site and the deposition of polychlorinated dibenzo-p-dioxins and dibenzofurans in the San Jacinto River and Houston Ship Channel.

The San Jacinto River (SJR) waste pits that lie just under the 1-10 overpass in eastern Harris County east of Houston, Texas, USA, were created in the 1960s as dumping grounds for paper mill waste. The deposition of this waste led to accumulation of highly toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCCDDs/PCDFs) over the course of several decades. After abandonment, the waste material eventually became submerged under the waters of the SJR, resulting in widespread environmental contamination that currently constitutes a significant health concern for eastern Harris County communities. The original waste pits were rediscovered in 2005, and the San Jacinto waste site is now a designated EPA superfund site. The objective of this review then is to discuss the history and current state of containment around the San Jacinto waste pits and analyze spatial and temporal trends in the PCDD/PCDF deposition through the SJR system from the data available. We will discuss the current exposure and health risks represented by the Superfund site and the SJR system itself, as well as the discovery of liver, kidney, brain (glioma), and retinoblastoma cancer clusters in eastern Harris County across multiple census tracts that border the Superfund site. We will also cover the two primary management options, containment versus removal of the waste from the Superfund and provide recommendations for increased monitoring of existing concentrations of polychlorinated waste in the SJR and its nearby associated communities.

AHR-related activities in a creosote-adapted population of adult atlantic killifish, Fundulus heteroclitus, two decades post-EPA superfund status at the Atlantic Wood Site, Portsmouth, VA USA

Atlantic killifish, Fundulus heteroclitus, are adapted to creosote-based PAHs at the US EPA Superfund site known as Atlantic Wood (AW) on the southern branch of the Elizabeth River, VA USA. Subsequent to the discovery of the AW population in the early 1990s, these fish were shown to be recalcitrant to CYP1A induction by PAHs under experimental conditions, and even to the time of this study, killifish embryos collected from the AW site are resistant to developmental deformities typically associated with exposure to PAHs in reference fish. Historically, however, 90 +% of the adult killifish at this site have proliferative hepatic lesions including cancer of varying severity. Several PAHs at this site are known to be ligands for the aryl hydrocarbon receptor (AHR). In this study, AHR-related activities in AW fish collected between 2011 and 2013 were re-examined nearly 2 decades after first discovery. This study shows that CYP1A mRNA expression is three-fold higher in intestines of AW killifish compared to a reference population. Using immunohistochemistry, CYP1A staining in intestines was uniformly positive compared to negative staining in reference fish. Livers of AW killifish were examined by IHC to show that CYP1A and AHR2 protein expression reflect lesions-specific patterns, probably representing differences in intrinsic cellular physiology of the spectrum of proliferative lesions comprising the hepatocarcinogenic process. We also found that COX2 mRNA expression levels were higher in AW fish livers compared to those in the reference population, suggesting a state of chronic inflammation. Overall, these findings suggest that adult AW fish are responsive to AHR signaling, and do express CYP1A and AHR2 proteins in intestines at a level above what was observed in the reference population.

Use of a Volunteer Monitoring Program to Assess Water Quality in a TMDL Watershed Utilized for Recreational Use, Pickens County, South Carolina

Municipalities, regulatory agencies, and resource advocacy organizations are often tasked with the enormous responsibility of monitoring water quality and implementing management strategies for vast areas within their jurisdictions. A potential means for addressing the resulting sampling shortfall is the use of volunteer monitoring programs. The project reported herein demonstrates the use of QA/QC protocols developed by Georgia Adopt-a-Stream (AAS) to monitor water quality issues for Twelve Mile Creek located in Pickens County, SC. The Twelve Mile watershed has a storied past as a U.S. EPA Superfund site due to industrial PCB contamination. Recent mitigation efforts involving the removal of two concrete dams have resulted in the creation of a nearly two-mile section of whitewater which is used by the local paddling community and is being marketed as a recreational destination. However, the Twelve Mile watershed also has a TMDL Implementation Plan in place due to chronic impairment from fecal coliform bacteria. Using sampling and monitoring methods developed by AAS, this project determined that E. coli levels increase significantly during high-flow discharges due to storm events and there were no significant differences in E. coli concentrations among sites located along a longitudinal gradient following the proposed Twelve Mile Creek Blueway. Ironically, the popularity of this area for paddling increases during periods of high discharge, thus recreational users are likely exposed to unhealthy levels of bacteria under these “desirable” conditions. Volunteer monitoring programs like AAS exhibit tremendous potential for gathering water quality data that may not be possible if left solely up to other stakeholders. Appropriately managed volunteer monitoring programs have the capability to increase the resolution, reach, and efficiency of existing monitoring programs and serve to benefit a variety of stakeholders.

Organochlorine contaminants and maternal offloading in the lecithotrophic Pacific angel shark (Squatina californica) collected from southern California

Pacific angel sharks (Squatina californica) are a benthic elasmobranch that occupy intermediate trophic level positions in coastal food webs. Angel sharks’ life history characteristics make them susceptible to accumulating high amounts of contaminants. Four angel sharks were opportunistically captured in southern California and their liver and uterine contents were analyzed for PCBs, DDTs and other pesticides. High DDT:PCB ratios were found in the sharks indicating direct or indirect foraging near a local EPA Superfund Site. Organic contaminants were measured in ovulated eggs, indicating that females are able to maternally offload contaminants. Despite the potential mismatch between ovarian and uterine fecundity, we estimated females to offload approximately 13±5% of their total body load, which represents the upper limit of this capability. Although low in sample size, the initial findings from this study suggest that habitat use might play an important role in contaminant accumulation in this species.

Surficial weathering of iron sulfide mine tailings under semi-arid climate

Mine wastes introduce anthropogenic weathering profiles to the critical zone that often remain unvegetated for decades after mining cessation. As such, they are vulnerable to wind and water dispersion of particulate matter to adjacent ecosystems and residential communities. In sulfide-rich ore tailings, propagation to depth of the oxidative weathering front controls the depth-variation in speciation of major and trace elements. Despite the prevalence of surficial mine waste deposits in arid regions of the globe, few prior studies have been conducted to resolve the near-surface profile of sulfide ore tailings weathered under semi-arid climate. We investigated relations between gossan oxidative reaction-front propagation and the molecular speciation of iron and sulfur in tailings subjected to weathering in a semi-arid climate at an EPA Superfund Site in central Arizona (USA). Here we report a multi-method data set combining wet chemical and synchrotron-based X-ray diffraction (XRD) and X-ray absorption near-edge spectroscopy (XANES) methods to resolve the tight coupling of iron (Fe) and sulfur (S) geochemical changes in the top 2m of tailings. Despite nearly invariant Fe and S concentration with depth (130–140 and 100–120gkg−1, respectively), a sharp redox gradient and distinct morphological change was observed within the top 0.5m, associated with a progressive oxidative alteration of ferrous sulfides to (oxyhydr)oxides and (hydroxy)sulfates. Transformation is nearly complete in surficial samples. Trends in molecular-scale alteration were co-located with a decrease in pH from 7.3 to 2.3, and shifts in Fe and S lability as measured via chemical extraction. Initial weathering products, ferrihydrite and gypsum, transform to schwertmannite, then jarosite-group minerals with an accompanying decrease in pH. Interestingly, thermodynamically stable phases such as goethite and hematite were not detected in any samples, but ferrihydrite was observed even in samples with the lowest pH, indicating its metastable persistence in these semiarid tailings. The resulting sharp geochemical speciation gradients in close proximity to the tailings surface have important implications for plant colonization, as well as mobility and bioavailability of co-associated toxic metal(loid)s.

An assessment of chemical contaminants in sediments from the St. Thomas East End Reserves, St. Thomas, USVI

The St. Thomas East End Reserves or STEER is located on the southeastern end of the island of St. Thomas, USVI. The STEER contains extensive mangroves and seagrass beds, along with coral reefs, lagoons, and cays. Within the watershed, however, are a large active landfill, numerous marinas, resorts, various commercial activities, an EPA Superfund Site, and residential areas, all of which have the potential to contribute pollutants to the STEER. As part of a project to develop an integrated assessment for the STEER, 185 chemical contaminants were analyzed in sediments from 24 sites. Higher levels of chemical contaminants were found in Mangrove Lagoon and Benner Bay in the western portion of the study area. The concentrations of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), zinc, copper, lead, and mercury were above a NOAA Effects Range-Low (ERL) sediment quality guideline at one or more sites, indicating impacts may be present in more sensitive species or life stages. Copper at one site in Benner Bay was above a NOAA Effects Range-Median (ERM) guideline indicating effects on benthic organisms were likely. The antifoulant boat hull ingredient tributyltin (TBT) was found at the third highest concentration in the history of NOAA's National Status and Trends (NS&T) Program, which monitors the nation's coastal and estuarine waters for chemical contaminants and bioeffects. The results from this project will provide resource managers with key information needed to make effective decisions affecting coral reef ecosystem health and gauge the efficacy of restoration activities.

Envisioning the political ecology of mitigation in a microelectronic disaster setting

This article draws on ethnographic data to explore lived experiences and narratives of mitigation unfolding in a toxic waste site in Endicott, New York, the birthplace of International Business Machines Corporation (IBM) and the location of a contentious U.S. EPA Superfund Site. It introduces the political ecology of mitigation concept and showcases how this critical approach to toxics repair can inform contemporary environmental social science discussions of environmental contamination and risk society. Envisioning the political ecology of mitigation, it is argued, calls for an ethnographic approach cognizant of politics of knowledge and expertise that invoke competing visions of mitigation in general and the efficacy of mitigation technologies and science in particular. Mitigation decisions are political and not simply scientific decisions. The political ecology of mitigation explored here pays close attention to the practices and processes through which toxics mitigation is wielded and negotiated. It shows how such practices and processes may inform contemporary perspectives on toxic neoliberal environments and ecologies.Key words: political ecology, toxics mitigation, IBM, neoliberalism, ethnography

Buildings, landscapes, and memory: case studies in historic preservation

Buildings, Landscapes, and Memory: Case Studies in Historic Preservation explores historically and critically the historic preservation movement in the United States. Analyzing ten extraordinary places, this provocative analysis of historic preservation's past and future will transform contemporary understanding of the movement, examining assumptions about why history, heritage, and place should matter. It ranges broadly from a discussion of the commemoration of place in the Marquis de Lafayette's triumphal tour of the United States in 1824-25 to speculation about the cultural and political import of interpreting history on EPA Superfund toxic waste sites. Thinking critically about preservation requires also thinking critically about its opposite: destruction. The book treats the movement to conserve the Hudson River Palisades from destruction at the hands of trap rock quarrymen as well as the effort to save Dutch-American homesteads that stood in the path of development in Brooklyn. It explores the intersection between race, culture, and preservation in the 1940s effort of African Americans to preserve the Mecca Flats in Chicago, an apartment building that was the subject of popular blues music and that was threatened by Mies van der Rohe's designs for the Illinois Institute of Technology. Focusing on the relationship among tradition, preservation, and modern design, Buildings, Landscapes, and Memory explores the making of Eero Saarinen's Jefferson National Expansion Memorial Arch on the historic Mississippi riverfront in St. Louis as well as the tension between tradition and modern design at Thomas Jefferson's University of Virginia, declared a World Heritage site in 1987. Engaging early efforts to build an economy on preservation and heritage tourism, the book also looks at the creation of Virginia's historic highway marker program in the 1920s.

Altered gonadal expression of TGF-β superfamily signaling factors in environmental contaminant-exposed juvenile alligators

Environmental contaminant exposure can influence gonadal steroid signaling milieus; however, little research has investigated the vulnerability of non-steroidal signaling pathways in the gonads. Here we use American alligators (Alligator mississippiensis) hatched from field-collected eggs to analyze gonadal mRNA transcript levels of the activin–inhibin–follistatin gene expression network and growth differentiation factor 9. The eggs were collected from Lake Woodruff National Wildlife Refuge, a site with minimal anthropogenic influence, and Lake Apopka, a highly contaminated lake adjacent to a former EPA Superfund site. The hatchling alligators were raised for 13 months under controlled conditions, thus limiting differences to embryonic origins. Our data reveal sexually dimorphic mRNA expression in 13-month-old alligator gonads similar to patterns established in vertebrates with genetic sex determination. In addition, we observed a relationship between lake of origin and mRNA expression of activin/inhibin subunits α and βB, follistatin, and growth differentiation factor 9. Our study suggests that embryonic exposure to environmental contaminants can affect future non-steroidal signaling patterns in the gonads of a long-lived species.

Ockham's Razor and autism: The case for developmental neurotoxins contributing to a disease of neurodevelopment

Much professional awareness regarding environmental triggers for ASD has been narrowly focused on a single possible exposure pathway (vaccines). Meanwhile, empirical support for environmental toxins as a broad class has been quietly accumulating. Recent research has shown that persons with ASD have comparatively higher levels of various toxins and are more likely to have reduced detoxifying ability, and, that rates of ASD may be higher in areas with greater pollution. This report documents that within the state with the highest rate of ASD, the rate is higher for schools near EPA Superfund sites, t (332) = 3.84, p = .0001. The reasons for the rise in diagnoses likely involve genetically predisposed individuals being exposed to various environmental triggers at higher rates than in past generations.

An enzyme-linked immunosorbent assay for the determination of dioxins in contaminated sediment and soil samples

A 96-microwell enzyme-linked immunosorbent assay (ELISA) method was evaluated to determine PCDDs/PCDFs in sediment and soil samples from an EPA Superfund site. Samples were prepared and analyzed by both the ELISA and a gas chromatography/high resolution mass spectrometry (GC/HRMS) method. Comparable method precision, accuracy, and detection level (8 ng kg −1) were achieved by the ELISA method with respect to GC/HRMS. However, the extraction and cleanup method developed for the ELISA requires refinement for the soil type that yielded a waxy residue after sample processing. Four types of statistical analyses (Pearson correlation coefficient, paired t-test, nonparametric tests, and McNemar’s test of association) were performed to determine whether the two methods produced statistically different results. The log-transformed ELISA-derived 2,3,7,8-tetrachlorodibenzo- p-dioxin values and log-transformed GC/HRMS-derived TEQ values were significantly correlated ( r = 0.79) at the 0.05 level. The median difference in values between ELISA and GC/HRMS was not significant at the 0.05 level. Low false negative and false positive rates (<10%) were observed for the ELISA when compared to the GC/HRMS at 1000 ng TEQ kg −1. The findings suggest that immunochemical technology could be a complementary monitoring tool for determining concentrations at the 1000 ng TEQ kg −1 action level for contaminated sediment and soil. The ELISA could also be used in an analytical triage approach to screen and rank samples prior to instrumental analysis.

Investigating changes of electrical characteristics of the saturated zone affected by hazardous organic waste

The Picillo Farm, EPA Superfund Site, in western Rhode Island was an unauthorized disposal site of hazardous organic chemicals. Predominantly organic contaminants have entered an aquifer comprised of layered glacial deposits and fractured bedrock and spread past the site boundaries with groundwater flow. Hydraulic conductivities in the glacial deposits range over two orders of magnitude and fractures and faults in the granitic bedrock further complicate the spreading of contaminants. Monitoring wells delineate two plumes that extend towards a fault-controlled valley with lakes and wetlands; one to the northwest and the other to the southwest. In this investigation we studied the electrical characteristics of both plumes. One dimensional Schlumberger depth soundings were conducted along several profile lines over the plumes and compared to those over non-contaminated sections of the site. With regard to the southwestern plume, high formation factors (ratio of bulk layer to pore water resistivity) between 12 and 45 were observed compared to values between 2.5 and 7.7 measured over the non-contaminated sections. Also, high values (> 5) of vertical electrical anisotropy (ratio of geoelectrically determined depth to high resistivity bedrock to drilled depth to bedrock) were measured over the contaminated part of the site. These values are extremely high compared to other non-contaminated sites (range: 2 to 3) in glacial stream channels of southern Rhode Island. Geoelectric measurements were affected by lateral effects. However, the consistency of high formation factors (11 to 35) and high vertical anisotropies (3 to 5) over the southwestern plume in comparison to low formation factors (3 to 8) and vertical anisotropies (1 to 1.5) over non-contaminated sites represents a marked difference between both sites. Overall, the Schlumberger depth soundings are less susceptible to near-surface lateral inhomogeneities than expected from other geoelectrical methods. Also, the disadvantage of a 1D interpretation was compensated by estimating resistivity and thickness ranges within the concept of non-uniqueness using the Dar Zarrouk parameters (Maillet, R., 1947. The fundamental equations of electrical prospecting. Geophysics, 12(4): 529–556.). The results over the northwestern plume, i.e. an area with higher contaminant concentration than the southwestern plume, were mixed and showed no consistent trends. Predominantly reducing conditions, as indicated by the presence of soluble ferric (FeII) iron hydroxides in ground water samples, increased the electrical conductivity. This is believed to have compensated the effect of high formation factors on the bulk saturated layer resistivity within the affected area.

Mercury Speciation, Reactivity, and Bioavailability in a Highly Contaminated Estuary, Berry’s Creek, New Jersey Meadowlands

Speciation and reactivity of mercury were examined in Berry's Creek estuary downstream of a highly mercury-contaminated U.S. EPA Superfund site during the summers of 2002 and 2003. Surface water samples from Berry's Creek estuary, its confluence with the Hackensack River, and upstream of that confluence were analyzed for total (THg), particulate (PHgT), and dissolved (DHg) mercury, total and particulate monomethylmercury (MeHg), dissolved gaseous mercury (DGM), and bacterial merA gene and transcript abundances. Surface water concentrations of THg in Berry's Creek estuary (210-6800 pM) are among the highest in North America. A downstream gradient of Hg contamination is a permanent feature of Berry's Creek estuary, and the upper estuary appears to be a perennial source of Hg to the lower estuary and the Hackensack River. MeHg concentrations in Berry's Creek surface waters ranged from 2 to 14 pM, with the highest concentrations occurring at a midestuary site 2 km downstream of the tide gate. The suspended particle phase dominated Hg and MeHg speciation throughout this system, accounting for > 90% of THg in Berry's Creek estuary and 35-94% of THg in the Hackensack River. Concentrations of DGM in Berry's Creek estuary (0.1-1.0 pM) are similar to levels of DGM in other much less contaminated estuaries (0.04-0.75 pM). In addition, expression levels of the bacterial mercuric reductase gene, merA, a gene of the inorganic Hg(II)-regulated, mercury resistance (mer) operon, were low throughout Berry's Creek estuary. Thus, despite very high concentrations of mercury in Berry's Creek estuary, relatively low concentrations of DGM and merA gene expression levels indicate limited bioavailability of inorganic Hg in the estuary's surface waters. A system-wide limitation on the bioavailability of inorganic Hg, together with bacterial demethylation activity, may account for observed MeHg concentrations that, although elevated, are lower than expected given the concentrations of THg in this estuary.

Rapid aryl hydrocarbon receptor based polymerase chain reaction screening assay for polychlorinated dibenzo- p-dioxins and furans in soil and sediment

A method for the estimation of polychlorinated dibenzo- p-dioxin and furan (PCCD/F) toxicity equivalent quotient (TEQ) of soil and sediment matrices is described. The method includes extraction, isolation of the PCDD/Fs from interfering compounds, such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), and measurement of PCDD/F using the PROCEPT ® aryl hydrocarbon (AhR) receptor based polymerase chain reaction (PCR) assay. The values obtained using the PROCEPT ® assay correlate well with reference TEQ values generated from gas chromatography–high resolution mass spectrometry (GC-HRMS), with a linearity coefficient ( R 2) of 0.94. Applied in a screening mode at 50 pg/g PCDD/F TEQ, the PROCEPT ® assay yielded five false positive results (2.6%) and no false negative results for 196 analyses of spiked soils and environmental samples obtained from US EPA Superfund sites.

Mercury in Tree Swallow Food, Eggs, Bodies, and Feathers at Acadia National Park, Maine, and an EPA Superfund Site, Ayer, Massachusetts

We monitored nest boxes during 1997-1999 at Acadia National Park, Mt. Desert Island, ME and at an old-field site in Orono, ME to determine mercury (Hg) uptake in tree swallow (Tachycineta bicolor) eggs, tissues, and food boluses. Also, in 1998-1999 we monitored nest boxes at Grove Pond and Plow Shop Pond at a U.S. Environmental Protection Agency Superfund site in Ayer, MA. We recorded breeding success at all locations. On average among locations, total mercury (THg) biomagnified 2 to 4-fold from food to eggs and 9 to 18-fold from food to feathers. These are minimum values because the proportion of transferable methyl mercury (MeHg) of the THg in insects varies (i.e., 35%-95% of THg) in food boluses. THg was highest in food boluses at Aunt Betty Pond at Acadia, whereas THg in eggs was highest at the Superfund site. A few eggs from nests at each of these locations exceeded the threshold (i.e., 800-1,000 ng/g, wet wt.) of embryotoxicity established for Hg. Hatching success was 88.9% to 100% among locations, but five eggs failed to hatch from 4 of the 11 clutches in which an egg exceeded this threshold. MeHg in feathers was highest in tree swallows at Aunt Betty Pond and the concentration of THg in bodies was related to the concentration in feathers. Transfer of an average of 80%-92% of the Hg in bodies to feathers may have enhanced nestling survival. Residues of Hg in tissues of tree swallows in the Northeast seem higher than those of the Midwest.

Uptake of lead and arsenic in food plants grown in contaminated soil from Barber Orchard, NC

Elevated levels of heavy metals in soil may allow uptake of these toxic species in food plants. Barber Orchard, Haywood County, NC has been designated a U.S. EPA Superfund site, primarily because of elevated levels of lead and arsenic. In this work, carrots, lettuce, and tomatoes were cultivated in a greenhouse in control soil and soil obtained from Barber Orchard. The resulting samples were then analyzed for lead and arsenic using inductively coupled plasma optical emission spectrometry (ICP–OES). Except for carrot roots grown in the contaminated soil, the concentrations of lead and arsenic in the plants were below the ICP-OES detection limit. The concentration of lead in carrot roots was 20 ± 11 μg/g, which represents a bioconcentration factor (BCF) of 0.03.

Characterization of lead and arsenic contamination at Barber Orchard, Haywood County, NC

Barber Orchard is a residential community in Western North Carolina that was declared a U.S. EPA Superfund Site in September 2001 because of elevated levels of arsenic, lead, and organochlorine compounds in the soil. The contamination was introduced by pesticides (e.g., lead arsenate, DDT) when the land was employed as an apple orchard. Concentration levels of lead and arsenic in soil were measured throughout two plots by inductively coupled plasma optical emission spectrometry. A linear relationship was observed between the moles of lead and arsenic. Sequential extraction procedures were employed to characterize the mobility and bioavailability of the metals. The major forms of both elements were bound to iron–manganese oxides. In general, the relative composition of the metal species did not statistically vary with depth, although higher concentration levels were observed near the surface. Brake ferns ( Pteris vittata) were employed in greenhouse phytoremediation experiments employing soil which had been homogenized to a uniform concentration level. Considerable variation was observed in the amount of arsenic absorbed by the ferns.