EPA's Toxic Release Inventory Research Articles

The wide presence of fluorinated compounds in common chemical products and the environment: a review.

The C-F bonds, due to their many unique features, have been incorporated into numerous compounds in countless products and applications. These fluorinated compounds eventually are disposed of and released into the environment through different pathways. In this review, we analyzed the occurrence of these fluorinated compounds in seven types of products (i.e., refrigerants/propellants, aqueous film-forming foam, cosmetics, food packaging, agrochemicals, pharmaceuticals, coating materials) and discussed their fate in the environment. This is followed by describing the quantity of fluorinated compounds from each source based on available data. Total on- and off-site disposal or other releases of 536 fluorinated compounds in 2021 were analyzed using the data sourced from the U.S. EPA Toxics Release Inventory (TRI). Among the chemicals examined, chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) were the primary contributors in terms of total mass. Upon examining the seven sources of fluorinated compounds, it became evident that additional contributors are also responsible for the presence of organofluorine compounds in the environment. Although various toxic degradation products of fluorinated compounds could form in the environment, trifluoroacetic acid (TFA) was specifically highlighted in this review given the fact that it is a common dead-end degradation product of > 1 million chemicals. This paper ended with a discussion of several questions raised from this study. The path forward was elaborated as well for the purpose of protecting the environment and human health.

Predicting Low-Level Childhood Lead Exposure in Metro Atlanta Using Ensemble Machine Learning of High-Resolution Raster Cells.

Low-level lead exposure in children is a major public health issue. Higher-resolution spatial targeting would significantly improve county and state-wide policies and programs for lead exposure prevention that generally intervene across large geographic areas. We use stack-ensemble machine learning, including an elastic net generalized linear model, gradient-boosted machine, and deep neural network, to predict the number of children with venous blood lead levels (BLLs) ≥2 to <5 µg/dL and ≥5 µg/dL in ~1 km2 raster cells in the metro Atlanta region using a sample of 92,792 children ≤5 years old screened between 2010 and 2018. Permutation-based predictor importance and partial dependence plots were used for interpretation. Maps of predicted vs. observed values were generated to compare model performance. According to the EPA Toxic Release Inventory for air-based toxic release facility density, the percentage of the population below the poverty threshold, crime, and road network density was positively associated with the number of children with low-level lead exposure, whereas the percentage of the white population was inversely associated. While predictions generally matched observed values, cells with high counts of lead exposure were underestimated. High-resolution geographic prediction of lead-exposed children using ensemble machine learning is a promising approach to enhance lead prevention efforts.

Socioeconomic disparities in exposures to unregulated industrial contaminants in U.S. public drinking water supplies

BACKGROUND AND AIMS Communities of color and low-income communities often face disproportionately high burdens of exposure to pollution. Previous studies investigating environmental justice and drinking water quality have focused on regulated contaminants with established standards, but many other unregulated contaminants are also present in drinking water. METHODS We evaluated associations between the presence of unregulated industrial contaminants and the demographics of communities served by U.S. public drinking water supplies (PWSs). We compiled data for four unregulated contaminants (1,4-dioxane, 1,1-dichloroethane, HCFC-22, PFAS) from U.S. EPA&amp;#x27;s Third Unregulated Contaminant Monitoring Rule (UCMR3). We analyzed data collected in 2013-2015 from 4,815 U.S. PWSs, serving 284 million people, that reported concentration data for at least one target contaminant. We also compiled information on PWS characteristics, county-level demographic data from the U.S. Census Bureau, and data on potential sources including airports, fire-training areas, wastewater treatment plants, and relevant contaminant releases reported in the U.S. EPA Toxic Release Inventory. RESULTS We found that PWSs serving counties with higher proportions of Hispanic residents and more urban households were more likely to have &amp;#x2265;1 target contaminant detected and were more likely to exceed a federal guideline for PFOA/PFOS or 1,4-dioxane, even after accounting for PWS characteristics and the presence of potential sources. Target contaminants were more frequently detected in large PWSs (&amp;#x3e;10,000 customers) compared to smaller systems and in groundwater systems compared to surface water systems. We did not find consistent associations between detection of UCMR3 contaminants and proportion of Black residents or proportion of residents considered deprived (according to the U.S. Census Bureau’s Multidimensional Deprivation Index). CONCLUSIONS Our findings provide new insight into the extent of socioeconomic disparities in exposures to drinking water contaminants and highlight the need to consider cumulative exposures to contaminants in drinking water. KEYWORDS Environmental justice, drinking water, contaminants, PFAS, industrial pollution

Air pollutant mixtures and autoimmune skin disease prevalence: findings from the Personalized Environment and Genes Study

BACKGROUND AND AIM: Autoimmune (AI) diseases are thought to be a product of genetic predisposition and environmental triggers. Disruptions of the skin barrier cause exacerbations of psoriasis where oxidative stress represents a mechanistic pathway for the pathogenesis of the disease. Oxidative stress is also thought to be the primary mechanism for the detrimental effects of air pollution. METHODS: We evaluated the association between the prevalence of autoimmune skin diseases (psoriasis or eczema,) and mixtures of air pollutants including six criteria air pollutants and constituents of PM2.5 in the Personalized Environment and Genes Study (PEGS) cohort consisting of 9414 subjects centered in NC, USA. We utilized land-use regression (LUR) predictions from the Center for Air, Climate, and Energy Solutions (CACES) and the Atmospheric Composition Analysis Group (ACAG). For increased spatial resolution, we included cumulative exposure to volatile organic compounds (VOC) based on the sum of exponentially decaying contributions from the EPA Toxic Release Inventory and the density of major roads within a 5km radius of a participant’s address. We will use logistic regression with quantile g-computation, adjusting for age, gender, income, and smoking history to evaluate the relationship between self-reported diagnosis of an AI skin condition and mean air pollution mixtures from 2000-2016. RESULTS:The PEGS cohort reported a high prevalence of autoimmune diseases with 3177 (33.7%) reporting 1+ AI disease. In our specific outcomes of interest, 1173 (12.5%) reported psoriasis (398) and/or eczema (873). Preliminary results for PM2.5 composition show that the mixture components of sulfate, black carbon, and nitrate contribute to a positive overall conditional odds ratio for risk of AI skin disease. CONCLUSIONS:Using publicly available LUR air pollution data joined with the PEGS cohort, we elucidate the potential important components of particulate exposure on AI skin disease. KEYWORDS: mixtures, air pollution, autoimmune disease, LUR,

Regulation-Induced Pollution Substitution

Abstract Environmental regulations may cause firms to reoptimize over pollution inputs. By regulating air emissions in particular counties, the Clean Air Act (CAA) gives firms incentives to substitute toward polluting other media, like waterways, and toward pollution from plants in other counties. I test these hypotheses using the EPA Toxic Release Inventory (TRI). Regulated plants increase their ratio of water-to-air emissions by 177% (102 log points) and their level of water emissions by 105% (72 log points). Regulation of an average plant increases air emissions at unregulated plants within the same firm by 11%.

EPA aims to crack down on ethylene oxide emissions

US chemical manufactures would have to trim their annual emissions of ethylene oxide, a carcinogenic gas, under an Environmental Protection Agency proposal. Ethylene oxide emissions from chemical manufacturing plants would be reduced by about 9 metric tons (t) per year under the proposed regulation, the EPA says. The agency wants to require facilities to control emissions of the gas from storage tanks, vents, and leaky equipment. Chemical plants collectively reported emitting about 100 t of ethylene oxide in 2018, according to the EPA Toxics Release Inventory. Of this, about 42 t were fugitive emissions that leak from vents, pumps, and valves, the inventory data show. Ethylene oxide is a chemical building block for making plastics, detergents, medicines, solvents, and a slew of other products. It is also used to sterilize medical devices. The proposed rule, which the EPA unveiled Nov. 6, is aimed at trimming about 105 t of hazardous

Visualizing Relative Potential for Aquatic Ecosystem Toxicity Using the EPA Toxics Release Inventory and Life Cycle Assessment Methods

The U.S. EPA Toxic Release Inventory has been available since 1987 as a record of industrial releases of toxic chemicals following the 1986 Emergency Planning and Community Right-to-Know Act. Combining this release data with estimates of relative toxicity of these chemicals to aquatic systems increases the value of the database by providing a common basis for comparison. The Tool for Reduction and Assessment of Chemicals and Other Environmental Impacts is a database of characterization factors to assess environmental impacts. It was used to develop relative ecotoxicity impacts and interpreted using Life Cycle Assessment concepts. The visualization software Tableau was used to generate representations of the preliminary results in this communication. The major potential sources of aquatic toxicity have been identified for South Carolina by industry type and by year over the period 1987–2016. The possibility of toxicity from releases of zinc compounds from power generation and pulp and paper mills far exceeds all other sources. Zinc compounds dominated the potential ecotoxicity over the full time period 1987–2016.

Public vs. Private Firms: Energy Efficiency, Toxic Emissions and Abatement Spending

We examine the effect of firm ownership status on three environmentally relevant variables: energy efficiency, toxic emissions and spending on pollution abatement. Prior research has demonstrated that public firms invest less than private firms and suggests this difference is due pressure from investors to strongly favor short over long-term earnings. We extend this logic to other firm behavior, examining whether publicly owned facilities invest in energy efficiency and pollution reduction differently than privately owned facilities. Using data from the US Census of Manufactures from 1980-2009, information on pollution from the EPA Toxic Release Inventory (TRI) and pollution abatement spending from the PACE survey, we find that facilities switching to public ownership are less energy efficient and spend less on pollution abatement than their privately owned counterparts. However, we also find that facilities switching to public ownership have lower toxic emissions than other facilities. We also examine how different sources of external pressures alter these results and find that increased regulatory scrutiny is correlated with increased energy efficiency, toxic emissions and abatement spending. More concentrated institutional ownership in public firms is associated with lower energy efficiency as is a greater brand focus. These latter results are broadly consistent with the idea that publicly owned firms respond to pressures from investors with a reduced focus on environmentally relevant variables. However, since facilities switching to public ownership have lower toxic emissions, this suggests that there are two competing pressures in publicly owned facilities: cost pressures, consistent with lowered energy efficiency, and public perceptions, consistent with lower toxic emissions, particularly since TRI data became available. In this sense, the combination of ownership and transparency of information appears to influence how firms prioritize different stakeholders.

Exposure to ambient dichloromethane in pregnancy and infancy from industrial sources and childhood cancers in California.

The incidence of childhood cancers has been increasing and environmental exposure to air toxics has been suggested as a possible risk factor. This study aims to explore ambient exposure to dichloromethane (methylene chloride). We frequency matched by birth year approximately 20 cancer-free controls identified from birth records to all childhood cancers ages 0-5 in the California Cancer Registry diagnosed from 1988 to 2012; i.e. 13,636 cases and a total of 270,673 controls. Information on industrial releases of dichloromethane within 3km of birth addresses was retrieved from mandatory industry reports to the EPA's Toxics Release Inventory (TRI). We derived exposure to dichloromethane within close vicinity of birth residences using several modeling techniques including unconditional logistic regression models with multiple buffer distances, inverse distance weighting, and quadratic decay models. We observed elevated risks for germ cell tumors [Odds Ratio (OR): 1.52, 95% Confidence Interval (CI) 1.11, 2.08], particularly teratomas (OR: 2.08, 95% CI 1.38-3.13), and possible increased risk for acute myeloid leukemias (AML) (OR: 1.64, 95% CI 1.15-2.32 in the quadratic decay model). Risk estimates were similar in magnitude whether releases occurred in pregnancy or the child's first year of life. Our findings suggest that exposure to industrial dichloromethane releases may be a risk factor for childhood germ cell tumors, teratomas, and possibly AML.

Effects of Climate Change on Environmental Hazards in Local Communities: A Data Visualization Prototype

Introduction: Although the effects of climate change on health risk have been extensively studied, it is unclear how climate change affects exposure pathways for environmental hazards. We create data visualization maps that inform policy makers to identify areas and people at greatest risk. Methods: Working with the EPA Toxics Release Inventory (TRI) Program and the Society for Chemical Hazard Communication (SCHC), we leveraged publicly available data (e.g. from the TRI, State health and environmental agencies, and NOAA and Landsat satellites) to develop an interactive web portal to display and communicate potential health and environmental effects of climate change on a disadvantaged neighborhood: the Near West Neighborhood. We created visualizations to identify: 1) locations at increased risk of flooding and associated vulnerabilities with respect to housing structures (mold), other critical infrastructure (including hospitals and schools), and contaminated sites and repositories for waste; 2) areas with an increased level of ozone formation from mobile and non-mobile sources of VOCs as they relate to increases in overall ambient temperature and localized urban heat island effects; and 3) hotspots where residents are more vulnerable to acute cardiovascular emergency call and hospitalization as a result of urban heat island effects. Results: these maps may aid decision-makers in identifying targeted areas and/or at-risk populations for disaster prevention, preparation, and response as a result of climate change and provides a cost-effective way to mitigate potential impacts of climate change. We have gained permission from the Near West Neighborhood to display this tool in the Neighborhood’s community center so the residents are empowered for environmental justice. Conclusion: the mapping tool will be invaluable for policy makers, as evidenced by our first prize award for the NIH/NIEHS Climate Change and Environmental Exposure Challenges. http://arcg.is/1K1mElG

"Public Vs. Private Firms: Energy Efficiency, Toxic Emissions And Abatement Spending"

In this paper, we examine the effect of ownership status on three environmentally relevant variables: energy efficiency, toxic emissions and spending on pollution abatement. Prior research has demonstrated that public firms invest less than private firms and suggests this difference in investment behavior is due to ‘short-termism’ - pressure from capital markets to strongly favor short over long term earnings. We extend this logic to other firm behavior, examining whether publicly owned plants invest in energy efficiency and pollution reduction differently than privately owned plants. Using data from the US Census of Manufactures from 1980-2009, linked with information on pollution from the EPA Toxic Release Inventory (TRI) and pollution abatement spending from the PACE survey, we find some evidence that publicly owned plants are less energy efficient, release more toxic emissions and spend less on pollution abatement than their privately owned counterparts. We also examine how different sources of external pressures alter these results and find that increased regulatory scrutiny is correlated with increased energy efficiency, toxic emissions and abatement spending. More concentrated institutional ownership in public firms is associated with lower energy efficiency as is a greater brand focus. These latter results are broadly consistent with the idea that publicly owned firms respond to pressures from capital markets with a reduced focus on environmentally relevant variables.

Quantity-based and toxicity-based evaluation of the U.S. Toxics Release Inventory

The U.S. EPA Toxics Release Inventory (TRI) represents an extensive, publicly available dataset on toxics and, as such, has contributed to reducing the releases and disposal of toxic chemicals. The TRI, however, reports on a wide range of releases from different sources, some of which are less likely to generate a human or ecological hazard. Furthermore, the TRI is quantity based and does not take into account the relative toxicity of chemicals. In an effort to utilize the TRI more effectively to guide environmental management and policy, this work provides an in-depth analysis of the quantity-based TRI data for year 2007 at industry sector, state, and chemical levels and couples it with toxicity potentials. These toxicity potentials are derived from the U.S. EPA's TRACI (Tool for the Reduction and Assessment of Chemical and other environmental Impacts) characterization factors for cancer, non-cancer and ecotoxicity. The combination of quantity-based and toxicity-based analysis allows a more robust evaluation of toxics use and priorities. Results show, for instance, that none of the highest priority chemicals identified through the toxicity-based evaluation would have been identified if only quantity-based evaluation had been used. As the chemicals are aggregated to the state and industry sector levels, the discrepancies between the evaluation methods are less significant.

Toward molecular design for hazard reduction—fundamental relationships between chemical properties and toxicity

The relationship of in-silico predicted physical/chemical properties and human toxicity is analyzed for a statistically significant sample size of chemical compounds. Results for compounds with known toxicity endpoints, as designated by EPA's Toxic Release Inventory (TRI), are compared to a series of commercial chemicals that are not regulated under TRI. Physical properties for all compounds are predicted using Schrodinger's QikProp, an established tool for predicting adsorption, distribution, metabolism, and excretion (ADME) characteristics. The results of this analysis indicate that the physical/chemical property distributions of TRI chemicals are statistically significantly different from those of bulk commercial chemicals, particularly related to properties associated with bioavailability. Using a partitioning analysis, several key physical/chemical properties and ranges are identified that can be used to readily differentiate TRI chemical characteristics from those of bulk commercial chemicals.

Globally sustainable manganese metal production and use

The “cradle to grave” concept of managing chemicals and wastes has been a descriptive analogy of proper environmental stewardship since the 1970s. The concept incorporates environmentally sustainable product choices—such as metal alloys utilized steel products which civilization is dependent upon. Manganese consumption is related to the increasing production of raw steel and upgrading ferroalloys. Nonferrous applications of manganese include production of dry-cell batteries, plant fertilizer components, animal feed and colorant for bricks. The manganese ore (high grade 35% manganese) production world wide is about 6 million ton/year and electrolytic manganese metal demand is about 0.7 million ton/year. The total manganese demand is consumed globally by industries including construction (23%), machinery (14%), and transportation (11%). Manganese is recycled within scrap of iron and steel, a small amount is recycled within aluminum used beverage cans. Recycling rate is 37% and efficiency is estimated as 53% [Roskill Metals and Minerals Reports, January 13, 2005. Manganese Report: rapid rise in output caused by Chinese crude steel production. Available from: http://www.roskill.com/reports/manganese.]. Environmentally sustainable management choices include identifying raw material chemistry, utilizing clean production processes, minimizing waste generation, recycling materials, controlling occupational exposures, and collecting representative environmental data. This paper will discuss two electrolytically produced manganese metals, the metal production differences, and environmental impacts cited to date. The two electrolytic manganese processes differ due to the addition of sulfur dioxide or selenium dioxide. Adverse environmental impacts due to use of selenium dioxide methodology include increased water consumption and order of magnitude greater solid waste generation per ton of metal processed. The use of high grade manganese ores in the electrolytic process also reduces the quantity of solid wastes generated during processing. Secondary aluminum facilities have reported hazardous waste generation management issues due to baghouse dusts from rotary furnaces processing selenium contaminated manganese alloys. Environmental impacts resulting from industry are represented by emission inventories of chemical releases to the air, water, and soil. The U.S. metals industry releases reported to EPA Toxic Release Inventory indicate the primary metals industry is the major source of metal air toxic emissions, exceeding electric utility air toxic emissions. The nonferrous metals industry is reported to be the Organization for Economic Co-operation and Development (OECD) most intensive airborne and land pollution source of bioaccumulative metals. However, total waste emissions from industries in the OECD countries have declined due to improving energy consumption. Emission registers and access are improving around the world. However, environmental databases for metal particulates have low confidence ratings since the majority of air toxic emissions are not reported, not monitored, or are estimated based on worst-case emission factors. Environmental assessments including biological monitoring are necessary to validate mandated particulate metal emission reductions and control technologies during metal processing.

Estimating the contribution of point sources to atmospheric metals using single-particle mass spectrometry

Single-particle mass spectra were collected using an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) during December of 2003 and February of 2004 at an industrially impacted location in East St. Louis, IL. Hourly integrated peak areas for twenty ions were evaluated for their suitability in representing metals/metalloids, particularly those reported in the US EPA Toxic Release Inventory (TRI). Of the initial twenty ions examined, six (Al, As, Cu, Hg, Ti, and V) were found to be unsuitable due to strong isobaric interferences with commonly observed organic fragments, and one (Be) was found to have no significant signal. The usability of three ions (Co, Cr, and Mn) was limited due to suspected isobaric interferences based on temporal comparisons with commonly observed organic fragments. The identity of the remaining ions (Sb, Ba, Cd, Ca, Fe, Ni, Pb, K, Se, and Zn) was substantiated by comparing their signals with the integrated hourly signals of one or more isotope ions. When compared with one-in-six day integrated elemental data as determined by X-ray fluorescence spectroscopy (XRF), the daily integrated ATOFMS signal for several metal ions revealed a semi-quantitative relationship between ATOFMS peak area and XRF concentrations, although in some cases comparison of these measurements were poor at low elemental concentrations/ion signals due to isobaric interferences. A method of estimating the impact of local point sources was developed using hourly integrated ATOFMS peak areas, and this method attributed as much as 85% of the concentration of individual metals observed at the study site to local point sources. Hourly surface wind data were used in conjunction with TRI facility emissions data to reveal likely point sources impacting metal concentrations at the study site and to illustrate the utility of using single-particle mass spectral data to characterize atmospheric metals and identify point sources.

A comparison of speciated atmospheric mercury at an urban center and an upwind rural location

Gaseous elemental mercury (GEM), particulate mercury (PHg) and reactive gaseous mercury (RGM) were measured every other hour at a rural location in south central Wisconsin (Devil's Lake State Park, WI, USA) between April 2003 and March 2004, and at a predominantly downwind urban site in southeastern Wisconsin (Milwaukee, WI, USA) between June 2004 and May 2005. Annual averages of GEM, PHg, and RGM at the urban site were statistically higher than those measured at the rural site. Pollution roses of GEM and reactive mercury (RM; sum of PHg and RGM) at the rural and urban sites revealed the influences of point source emissions in surrounding counties that were consistent with the US EPA 1999 National Emission Inventory and the 2003-2005 US EPA Toxics Release Inventory. Source-receptor relationships at both sites were studied by quantifying the impacts of point sources on mercury concentrations. Time series of GEM, PHg, and RGM concentrations were sorted into two categories; time periods dominated by impacts from point sources, and time periods dominated by mercury from non-point sources. The analysis revealed average point source contributions to GEM, PHg, and RGM concentration measurements to be significant over the year long studies. At the rural site, contributions to annual average concentrations were: GEM (2%; 0.04 ng m(-3)); and, RM (48%; 5.7 pg m(-3)). At the urban site, contributions to annual average concentrations were: GEM (33%; 0.81 ng m(-3)); and, RM (64%; 13.8 pg m(-3)).

The toxic release inventory: Fact or fiction? A case study of the primary aluminum industry

Since 1989 manufacturing facilities across the USA must report toxic chemical emissions to the EPA's toxic release inventory (TRI). Public release of this information and increased public scrutiny are believed to significantly contribute to the over 45% reduction in toxic chemical releases since inception of the program and to growing support for this type of informational regulation instead of traditional command-and-control. However, prior research indicates a tendency to under-report emissions. We find specific evidence of under-reporting of polycyclic aromatic hydrocarbons (PAH) to the TRI by primary aluminum facilities after promulgation of the industry's maximum available control technology (MACT) standard in 1997. We also find evidence of dislocation of emission overseas due to these regulatory requirements. Additionally, changes in energy prices affected aluminum production and further distort reported PAH emissions levels. This suggests the possibility of more widespread under-reporting that is modulated by various factors, including market conditions and new regulations, and which may partially explain the downward trend in TRI emissions. It also suggests that the quality of TRI data may improve once facilities are subject to monitoring of emissions of a TRI listed pollutant due to command-and-control regulation.

Application of PSCF and CPF to PMF-Modeled Sources of PM2.5in Pittsburgh

Ambient PM 2.5 composition data in Pittsburgh, PA have been used with Positive Matrix Factorization (PMF) to determine the major sources of PM 2.5 sampled. This paper describes the use of the potential source contribution function (PSCF) with the PMF-modeled source contributions to locate the sources in a grid of 0.1° × 0.1° cells. The domain extends from the Pittsburgh Supersite at 40.44°N, 79.94°W over the range 35°–50° north latitude and 75°–90° west longitude. Six-hour back trajectories have been obtained from HYSPLIT four times each day for the 13 months of the study for use with PSCF. Using the results, higher probability locations are compared with known locations of specific source types, based on information from the EPA Toxic Release Inventory (TRI) and the EPA AIRS Database. PSCF results for several sources are compared to the conditional probability function (CPF) analysis, which uses 15-minute wind direction data to determine the most probable direction of a source. Using PSCF and CPF togethe...

Near and Not-So-Dear TRI Facilities: Prenatal Proximity and Later BrainCancer

The most clearly established environmental risk factor for childhood brain cancer is therapeutic radiation exposure (not including diagnostic X-rays). New research now suggests that children of mothers who lived near an EPA Toxics Release Inventory (TRI) facility while pregnant may be more likely to later develop brain cancer, especially if the site released carcinogens [EHP 114:1113–1118; Choi et al.]. Prenatal exposure to chemicals can have profound long-term effects, as some toxic chemicals that are stopped by the blood–brain barrier in adults may reach the fetus via the placenta. This work is the first to specifically examine brain cancer risk in children and potential exposure to TRI releases, although some previous research has suggested slight increases in risk for certain birth defects associated with such emissions. Of the more than 650 toxic chemicals listed in the TRI, 193 are known or suspected carcinogens, according to the EPA. Fifty-five known, probable, or possible carcinogens were actually released within 2 miles of the study participants. However, it is very difficult to accurately assess exposure to TRI releases. The TRI itself shows only the type and mass of chemicals released in a given year, not where the chemicals went or precisely when they were released. Because of the uncertainty built into using these data, studies such as this must be interpreted with caution. The study included 382 children diagnosed with brain cancer before age 10 and an equal number of cancer-free controls analyzed as pairs. Mothers of children whose brain cancer was diagnosed before age 10 years were nearly 50% more likely to have lived within 1 mile of such a site during pregnancy; the likelihood was nearly 75% higher for children diagnosed before age 5. However, when looking at risk for two major childhood brain cancer types in particular, astrocytoma and primitive neuroectodermal tumors, there was no difference. The team used EPA Region III’s chronic toxicity index, which combines total mass released with toxicity factors including carcinogenic weight of evidence and cancer potency factors. For this study, inhalation and oral cancer potency factors were included. Other potential factors, such as mothers’ exposures in the work-place during pregnancy, children’s postnatal exposure, and exposure through contaminated drinking water, were not taken into account. The authors therefore caution that their results are not conclusive, but should be replicated and expanded using improved exposure measures.

Evaluation of two different biomarkers for use in the assessment of toxic chemical exposure in California sea lions ( Zalophus californianus)

Industrial pollution is a significant environmental problem that has the potential to cause serious health consequences in humans and wildlife. In 1998, over 248 million pounds of toxic chemicals were reportedly released into the surface water of rivers, bays and the oceans (US EPA Toxic Release Inventory (TRI), 1998). Examples of these toxicants, according to the TRI, include trichloroethylene, benzene, 1,3-butadiene, glycol ethers, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and mercury. Once toxicants enter the aquatic environment, they can accumulate in the benthic sediments, be distributed throughout the water column, be incorporated by organisms, and then bioaccumulate up the food chain. The benthic sediments often act as an almost limitless reservoir for environmental contaminants and continually change in response to both abiotic and biotic conditions (Malins and Ostrander, 1991). The sea-surface microlayer, the upper 50 lm of the water column, is an area of particular concern for some species, as some contaminant concentrations, such as aromatic hydrocarbons, are 10–1000 times higher in this layer than in the