A risk assessment on zinc and zinc compounds was carried out within the framework of Council Regulation 793/93/EEC on Existing Chemicals. This risk assessment basically followed the European Union (EU) technical guidance documents (TGDs). These TGDs are built on the current knowledge on quantitative risk assessments, mainly for organic chemicals. This article describes the tailor-made approach for the zinc risk assessment. This work lasted almost a decade and involved the contributions of all EU member states and industry, who discussed the risk assessment during technical meetings. The risk assessment is initially based on scientific findings but is interrelated with pragmatic considerations. It follows a comprehensive approach, covering both environmental and human health. In the environmental part, new methodologies were developed to deal with the natural background of zinc, essentiality, speciation, and the use of species sensitivity distributions. The major results and the process of drawing conclusions of the risk assessment are outlined: potential environmental risks of zinc and zinc compounds may occur at local and regional scales in surfacewater, sediment, and soil. No potential health risks were identified for consumers and man indirectly exposed via the environment. For workers, potential health risks were identified only for zinc oxide and zinc chloride.

This review evaluates the methodologies of 13 screening value (SV) compilations that have been commonly used in ecological risk assessment (ERA), including compilations from state and U.S. federal agencies, the Oak Ridge National Laboratory (ORNL), Canada, The Netherlands, and Australia. The majority of surfacewater SVs were primarily derived for the protection of aquatic organisms using 2 approaches: (1) a statistical assessment of toxicity values by species groupings, such as “ambient water quality criteria,” or (2) extrapolation of a lowest observed adverse effect level determined from limited toxicity data using an uncertainty factor. Sediment SVs were primarily derived for the protection of benthic invertebrates using 2 approaches: (1) statistical interpretations of databases on the incidence of biological effects and chemical concentrations in sediment, or (2) values derived from equilibrium partitioning based on a surfacewater SV. Soil SVs were derived using a diversity of approaches and were usually based on the lowest value determined from soil toxicity to terrestrial plants or invertebrates and, less frequently, from modeled, incidental soil ingestion or chemical accumulation in terrestrial organisms. The various SV compilations and methodologies had varying levels of conservatism and were not consistent in the pathways and receptors considered in the SV derivation. Many SVs were derived from other compilations and were based on outdated values, or they relied on only older toxicity data. Risk assessors involved in ERA should carefully evaluate the technical basis of SVs and consider the uncertainty in any value used to determine the presence or absence of risk and the need for further assessment.

Copper (Cu) concentrations in waterways of the United States are of widespread concern. Presently, 692 waterway segments around the United States are listed by the U.S. Environmental Protection Agency (USEPA) as having unacceptably high copper concentrations. As part of their water quality management strategy, the USEPA is mandated to understand and manage sources and impacts of nonpoint releases of chemicals of concern. One potential nonpoint source of Cu is the runoff of precipitation falling onto Cu used in external architecture (e.g., roofing). However, few studies of Cu roof runoff have been published. This article is intended to provide estimations of Cu runoff rates and concentrations across the United States. Copper runoff rates and concentrations are predicted at 179 locations with a recently developed model. The average and range (in parentheses) of annual Cu loading rates, based on roof area; Cu export rates, based on amount of precipitation; and Cu concentrations for the United States are 2.12 (1.05–4.85) g Cu/m²/y; 2.72 (0.69–16.48) mg Cu/m²/mm; and 2.72 (0.69–16.48) mg Cu/L as total Cu, respectively. Statistics are presented that describe site-specific data distributions for use in probabilistic exposure and risk assessments. The effects of air quality as well as the potential fate and risks of Cu from roof runoff are discussed.

Data on Polybrominated diphenylether (PBDE) concentrations in individual U.S. women were compiled. PBDE levels in adipose tissue, serum, and breast milk from individual U.S. women were found to follow similar lognormal distributions, which exhibited a high degree of variability. The distribution of lipid-normalized PBDE concentrations for all media combined had a median of 47.9 ng/g and a 95th percentile estimate of 302 ng/g. Estimates of congener-specific kinetic parameters were used to calculate the total daily intake of the PBDEs (sum of 5 PBDE prominent congeners, PBDE-47, -99, -100, -153, and -154) that would be required to achieve the measured body burdens. PBDE intake estimates from all routes of exposure were 8.5 ng/kg/d (median) and 54 ng/kg/d (95th percentile). The potential health risks posed by the PBDEs were examined by comparing 95th percentile tissue concentrations in humans (C_human) to modeled and measured tissue concentrations in rodents that caused no developmental neurotoxicity and reproductive effects (C_rodent). The ratio of rodent-to-human PBDE concentrations (C_rodent:C_human) was <1 for alterations of male and female reproductive organs in rats, <10 for neurodevelopmental effects in mice, and <100 for neurodevelopmental effects in rats. If humans are as sensitive as animals to PBDE-induced developmental toxicity, the current margin of safety appears low for a fraction of the population.

Since the 1997 local ban on ocean dumping of dredged sediments, the state of New Jersey has pursued a policy of environmentally sound solutions to the controversial problem of dredged material management, including beneficial use of dredged material stabilized with pozzolanic additives (SDM). A pilot study was initiated in 1998 to evaluate the use of SDM in the construction of highway embankments. Using 80,000 cubic yards of silty dredged material, 2 embankments were constructed from SDM on a commercial development area adjacent to the New York/New Jersey Harbor. This article presents the evaluation of the environmental effects of the SDM, including fugitive air emissions, leachate, and stormwater quality. Engineering properties, handling and management techniques of the SDM, constructability, and performance were also evaluated, the results of which are published elsewhere. The findings demonstrate that although there are measurable releases of contaminants to the environment from the SDM, these releases are not significant long-term threats to human health or the environment. Policies currently in place to regulate the management of SDM that include limiting placement options to previously contaminated sites with institutional and engineering controls will further reduce the potential for environmental impact and, in fact, have the potential to produce significant environmental benefit.

Conservation of water quality is inherently tied to watershed management. Efforts to protect Lake Baikal have increasingly focused on the Selenge River, a major tributary, with more than half its watershed area in Mongolia. Placer gold mining in Mongolia has the potential to load total suspended sediment (TSS), and total phosphorus (TP) into Lake Baikal and destroy spawning areas for the endangered Taimen salmon (Hucho taimen taimen). This work describes water quality assessments performed from 2001 to 2003 on Mongolian tributaries to the Selenge River. Of 7 rivers sampled, rivers with proximal mining had the worst water quality. Elevated loading of TSS and TP was observed below mining regions on the Tuul River. Flooding could breach thin strips of land separating dredge pits from river channels, resulting in massive sediment loading. Extensive disturbance of the river terrace was apparent for many square kilometers. In the mountainous headwaters of the Yeroo River, tributary drainages undergoing mining had TP concentrations 8 to 15 times higher than the main stem. TSS was 7 to 12 times higher, and turbidity was 8 times higher. Alternative mining technologies exist that could minimize impact and improve the possibility for reclamation.

Estuaries in urban regions present unique environmental management challenges. Ecosystems in urban estuaries are typically impacted by habitat loss and degradation, watershed modification, and nonpoint and point sources of many chemicals. Restoring such systems requires an understanding of the relative contribution of various stressors to overall ecological conditions and an understanding of shifting patterns of stress over time. In this article, we present the results of a multiparameter environmental assessment of a quintessential urbanized waterway: the lower Passaic River in the vicinity of Newark, New Jersey, USA. To provide the foundation for effective management decision making, we quantified baseline conditions (habitat losses and degradation), chemical concentrations in sediment and biota relative to published toxic effect levels, direct toxicity of sediments to benthic organisms, and food-web mediated risks to fish-eating birds. Habitat losses have been severe (greater than 85% of wetlands, nearly 100% of the total length of tidal and nontidal tributaries, and 100% of natural shoreline habitat have been lost), resulting in substantial habitat constraints on biota. Despite this, biological communities are present in the lower Passaic. In general, concentrations of toxic chemicals in surface sediments have fallen with time, and natural recovery processes are proceeding. Chemical concentrations remain high enough to impair survival of amphipods, but not amphipod growth or polychaete growth or survival as measured in laboratory bioassays using field-collected sediment. Fish and blue crab body burdens of some metals, PCBs, and the pesticide, DDT, are at concentrations sufficiently high to exceed toxicity thresholds. The resident fish-eating bird—the belted kingfisher—is at exposure risk from some metals, PCBs, and polychlorinated dibenzo-p-dioxins and dibenzo furans (PCDD/Fs). Migratory waders—the herons and egrets—are not at risk from chemical exposure. These complex findings suggest that restoring the lower Passaic River to ecological health is a correspondingly complex task. Habitat constraints must be eased for biotic components of the ecosystem, and chemical effects must be reduced for those organisms that are present. Only a coordinated, multidisciplinary restoration program will succeed in this challenging environment.

Limited hunting of deer at the future Rocky Flats National Wildlife Refuge has been proposed in U.S. Fish and Wildlife planning documents as a compatible wildlife-dependent public use. Historically, Rocky Flats site activities resulted in the contamination of surface environmental media with actinides, including isotopes of americium, plutonium, and uranium. In this study, measurements of actinides [Americium-241 (²⁴¹Am); Plutonium-238 (²³⁸Pu); Plutonium-239,240 (^239,240Pu); uranium-233,244 (^233,234U); uranium-235,236 (^235,236U); and uranium-238 (²³⁸U)] were completed on select liver, muscle, lung, bone, and kidney tissue samples harvested from resident Rocky Flats deer (N = 26) and control deer (N = 1). In total, only 17 of the more than 450 individual isotopic analyses conducted on Rocky Flats deer tissue samples measured actinide concentrations above method detection limits. Of these 17 detects, only 2 analyses, with analytical uncertainty values added, exceeded threshold values calculated around a 1 × 10⁻⁶ risk level (isotopic americium, 0.01 pCi/g; isotopic plutonium, 0.02 pCi/g; isotopic uranium, 0.2 pCi/g). Subsequent, conservative risk calculations suggest minimal human risk associated with ingestion of these edible deer tissues. The maximum calculated risk level in this study (4.73 × 10⁻⁶) is at the low end of the U.S. Environmental Protection Agency's acceptable risk range.

Discussions and applications of the policies and practices of the U.S. Environmental Protection Agency (USEPA) in ecological risk assessment will benefit from continued clarification of the concepts of assessment endpoints and of levels of biological organization. First, assessment endpoint entities and attributes can be defined at different levels of organization. Hence, an organism-level attribute, such as growth or survival, can be applied collectively to a population-level entity such as the brook trout in a stream. Second, assessment endpoints for ecological risk assessment are often mistakenly described as “individual level,” which leads to the idea that such assessments are intended to protect individuals. Finally, populations play a more important role in risk assessments than is generally recognized. Organism-level attributes are used primarily for population-level assessments. In addition, the USEPA and other agencies already are basing management decisions on population or community entities and attributes such as production of fisheries, abundance of migratory bird populations, and aquatic community composition.