Environmental Protection Agency's Monitoring Research Articles

Correlation of ambient pollution levels and heavily-trafficked roadway proximity on the prevalence of smear-positive tuberculosis

Varying levels of evidence exist for the contribution of indoor air pollution and environmental tobacco smoke as a risk factor for tuberculosis (TB). Despite a similar mechanism of action, the influence of outdoor air pollution exposure as an independent contributor to TB disease has yet to be explored. This area of inquiry is of increasing importance given the level of pollution in the rising economies of many TB-endemic nations. Los Angeles' unique physical environs and traffic patterns mirror other global megacities with a greater burden of TB therefore allowing for preliminary correlative studies. This preliminary study hypothesizes that individuals who reside proximal to elevated pollutant exposures are likely to have a greater burden of disease--as evidenced by sputum smear-positive TB. Retrospective medical records review. Medical records of non-homeless individuals (n = 196) diagnosed with culture positive TB at Los Angeles County and University of Southern California Medical Center Hospital were analyzed from January 2007 to December 2008. The study population was grouped according to acid-fast bacilli (AFB) smear-positive (n = 111) and smear-negative (n = 85) status. Air pollutant exposure was captured using measurements of ozone (O3) and particulate matter with an aerodynamic diameter of less than 2.5 (PM2.5). Individual assignment to O3 and PM2.5 exposures were based on residential proximity to the nearest US Environmental Protection Agency's monitoring station. Proximity of home residences to traffic-related pollutants occurred by measurement of distance to the nearest freeway and major non-freeway road. Single factorial models yielded a significant correlation of smear-positive status and residential exposure to PM2.5. Residential distance to freeways and major arterial roads did not yield an association. This is the first report linking ambient pollution exposure as a risk factor for TB. PM2.5 may have the potential to impact TB lung pathology as evidenced by the linkage of fine particulate matter levels and smear-positive TB.

Effect of residential proximity to major roadways on cystic fibrosis exacerbations

Ambient air pollution has been attributed with an increase in exacerbation frequencies among the cystic fibrosis (CF) population. This study correlates exacerbation frequency with proximity to roadways and two criteria air pollutants. Clinical data was extracted from the Cystic Fibrosis Foundation National Patient Registry and Electronic Medical Records at Children's Hospital Los Angeles (CHLA). Average annual air pollutant levels were obtained from selected US Environmental Protection Agency's monitoring stations. Geographic proximity to monitoring stations and roadways were analyzed using spatial mapping software. A total of 145 patients from the CHLA's CF center were characterized by a dichotomous exacerbation category. No significant association was determined between the frequency of exacerbations and exposure to fine particulate matter and ozone levels. Residential proximity to US-designated highways and freeways also did not achieve significance (p = 0.3777) but was noted to be correlated with major arterial roadways (p = 0.0420). Associations of environmental exposures may have important implications for future predictive models of CF clinical outcomes.

Comparison of pollution levels on the Mississippi Gulf Coast during the 2010 Gulf BP oil spill to ecological and health-based standards

To evaluate the possible impact that the BP Deepwater Horizon Gulf oil spill might have had on pollution levels in the State of Mississippi, the Mississippi Department of Environmental Quality (MDEQ), and the US Environmental Protection Agency (EPA) analyzed surface water and ambient air quality pollutant data taken from MDEQ and EPA monitoring sites on the Mississippi Gulf Coast. The data were compared with acute, chronic, and human health air and water quality standards to determine whether the pollutant levels occurring during the oil spill could cause ecological and/or human health effects. The water quality data indicated levels of nickel, vanadium, volatile organic compounds (VOCs), and semivolatile organic compounds analyzed remained below acute and chronic levels for both aquatic life and human health. The air quality sampling data showed that the levels of VOCs and polycyclic aromatic hydrocarbons associated with the oil spill were well below EPA chronic and human health screening levels. A comparison of the air quality monitoring data taken before and after the oil spill showed that the concentrations of ozone and fine particulate matter were elevated for brief periods but remained below actionable levels.

THE POTENTIAL INDICATOR VALUE OF RARE TAXA RICHNESS IN DIATOM-BASED STREAM BIOASSESSMENT1.

Despite their recognized contribution to species richness, the importance of rare taxa richness in bioassessment is unclear. This study aimed to characterize the environmental factors affecting the number of rare diatom taxa in western U.S. streams and rivers, and to evaluate whether this number can be used to differentiate streams with contrasting human disturbance. Three different categories of rare taxa were used: satellite (taxa with low occurrence and low abundance), rural (taxa with high occurrence and low abundance), and urban (taxa with low occurrence and high abundance). Common taxa were included as a separate category of core taxa (taxa with high occurrence and high abundance). We analyzed 987 diatom samples collected over the period of 5 years (2000-2004) for the U.S. Environmental Protection Agency's (EPA) Western Environmental Monitoring and Assessment Program (WEMAP). The results showed that rural taxa richness (number of rural taxa per site) increased along a longitudinal gradient from mountainous, fast-flowing oligotrophic streams with fewer fine substrates to large, slow-moving, nutrient-rich rivers with abundance of fine substrates. Rural taxa richness was the only rarity metric that distinguished least disturbed (reference) sites from the most disturbed (impacted) sites, but it was significantly different only in the mountains ecoregion. Core taxa richness distinguished reference from impacted sites in the West and in each one of the three ecoregions (mountains, plains, and xeric). Our findings revealed that rural taxa richness can be used as an indicator of human disturbance in streams/rivers, especially in the mountains ecoregion, and that rarity definition is important in bioassessment.

Probability surveys, conditional probability, and ecological risk assessment

We show that probability-based environmental resource monitoring programs, such as the U.S. Environmental Protection Agency's (U.S. EPA) Environmental Monitoring and Assessment Program, and conditional probability analysis can serve as a basis for estimating ecological risk over broad geographic areas. Under certain conditions (including appropriate stratification of the sampled population, sufficient density of samples, and sufficient range of exposure levels paired with concurrent response values), this empirical approach provides estimates of risk using extant field-derived monitoring data. The monitoring data were used to prescribe the exposure field and to model the exposure-response relationship. We illustrate this approach by estimating risks to benthic communities from low dissolved oxygen (DO) in freshwater streams of the mid-Atlantic region and in estuaries of the Virginian Biogeographical Province of the United States. In both cases, the estimates of risk are consistent with the U.S. EPA's ambient water quality criteria for DO.

Can sediment total organic carbon and grain size be used to diagnose organic enrichment in estuaries?

Eutrophication (i.e., nutrient enrichment, organic enrichment, and oxygen depletion) is one of the most common sources of impairment in Clean Water Act 303(d)-listed waters in the United States. Although eutrophication can eventually cause adverse effects to the benthos, it may be difficult to diagnose. Sediment organic carbon (OC) content has been used as an indicator of enrichment in sediments, but the amount of surface area available for carbon adsorption must be considered. We investigated the utility of the relationship between OC and sediment grain size as an indicator of eutrophication. Data from the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program was used to test this relationship. However, anthropogenic contaminants are also capable of causing adverse effects to the benthos and often co-occur with elevated levels of OC. Contaminant analysis and toxicity tests were not consistently related to enrichment status as defined by relationship between total OC and grain size. Although variability in response occurred, reflecting the variance in the water column factors (dissolved oxygen, chlorophyll a, and nutrients) and limited sample sizes, the data supported the hypothesis that sites designated as enriched were eutrophied. Dissolved oxygen levels were reduced at enriched sites, whereas chlorophyll a and nutrients were higher at enriched sites. This suggests that the relationship of OC to grain size can be used as a screening tool to diagnose eutrophication.

A method to identify estuarine macroinvertebrate pollution indicator species in the Virginian Biogeographic Province

Abstract Macroinvertebrates are commonly used as biomonitors to detect pollution impacts in estuaries. The goal of this research was to identify estuarine benthic invertebrates that could be used as indicator species to detect presence or absence of pollution in the Virginian Biogeographic Province using available monitoring data from the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program. The data were first subdivided by habitat. Then we summarized the benthic community using principal coordinates analysis and projected the results onto a pollution gradient. Then we compared medians and corrected interquartile ranges to identify indicator species that were sensitive to pollution (or lack thereof) and showed low variation in response. Our data set was divided into smaller subsets that ranged from 108 to 532 stations per habitat. Out of 707 species in the Virginian Province, 67 were identified as pollution indicator species; 37 pollution sensitive taxa and 30 pollution tolerant taxa. The pollution sensitive taxa were represented by more phyla than were the pollution tolerant taxa. The pollution tolerant taxa were dominated by deposit feeders while the pollution sensitive taxa were not dominated by animals using any one feeding strategy. The pollution sensitive taxa included many crustaceans, known to be sensitive to pollution, while the pollution tolerant taxa included many tubificid oligochaetes, which are common indicators of pollution. Our empirically based results corresponded well with other studies that identified tolerance values or indicator species. One advantage of this technique is that it can be used on smaller data sets, assuming that there are not major habitat differences among the samples. We believe that this parsimonious technique can be applied to other coastal areas where mid-size (100–500 stations) monitoring data sets are available.

Fish Assemblage Relationships with Physical Habitat in Wadeable Iowa Streams

AbstractFish assemblages play a key role in stream ecosystems and are influenced by physical habitat. We analyzed fish assemblages and physical habitat at 93 randomly selected sites on second‐ through fifth‐order wadeable Iowa streams to explore fish assemblage relationships with reach‐scale physical habitat in this agriculturally dominated landscape. Sites were sampled using DC electrofishing and the wadeable streams physical habitat protocol of the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program. In all, 82 species were collected, with species richness at sites averaging 14. Over 80% of the sites had fish assemblages rated as fair (53%) or poor (32%) based on a fish index of biotic integrity (FIBI). Ordination separated sites from the two major river drainages along an axis of impairment, with sites in the Missouri River drainage exhibiting lower FIBI scores than sites in the Mississippi River drainage. Physical habitat at most sites exhibited fine substrates, eroding banks, and low‐gradient, nonmeandering channel and was dominated by glides. Thirty physical habitat variables describing channel morphology, channel cross section and bank morphology, fish cover, human disturbance, large woody debris, relative bed stability, residual pool, riparian vegetation, and substrate differed significantly between sites with FIBI scores rated as poor and those with FIBI scores rated as good or excellent. Eighteen physical habitat variables were significant predictors of fish assemblage metrics and FIBI in multiple linear regression models, with adjusted R2 values ranging from 0.12 to 0.58. Seventy percent of the model coefficients reflected substrate (40%), residual pool (21%), and fish cover (9%) variables. Fish assemblages in wadeable Iowa streams are strongly associated with the quality of physical habitat. Thus, understanding and addressing the determinants of physical habitat are crucial for managing streams in Iowa and other agricultural regions.

A Predictive Index of Biotic Integrity Model for Aquatic‐Vertebrate Assemblages of Western U.S. Streams

AbstractBecause of natural environmental and faunal differences and scientific perspectives, numerous indices of biological integrity (IBIs) have been developed at local, state, and regional scales in the USA. These multiple IBIs, plus different criteria for judging impairment, hinder rigorous national and multistate assessments. Many IBI metrics are calibrated for water body size, but none are calibrated explicitly for other equally important natural variables such as air temperature, channel gradient, or geology. We developed a predictive aquatic‐vertebrate IBI model using a total of 871 stream sites (including 162 least‐disturbed and 163 most‐disturbed sites) sampled as part of the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program survey of 12 conterminous western U.S. states. The selected IBI metrics (calculated from both fish and aquatic amphibians) were vertebrate species richness, benthic native species richness, assemblage tolerance index, proportion of invertivore‐piscivore species, and proportion of lithophilic‐reproducing species. Mean model IBI scores differed significantly between least‐disturbed and most‐disturbed sites as well as among ecoregions. Based on a model IBI impairment criterion of 0.44 (risks of type I and II errors balanced), an estimated 34.7% of stream kilometers in the western USA were deemed impaired, compared with 18% for a set of traditional IBIs. Also, the model IBI usually displayed less variability than the traditional IBIs, presumably because it was better calibrated for natural variability.

Surface Area Estimates of Streams and Rivers Occupied by Nonnative Fish and Amphibians in the Western USA

AbstractStatistically robust, broad‐scale measures of the portion of an aquatic resource (e.g., a stream and river network) occupied by nonnative fish and amphibian species should be useful to resource managers but with a few exceptions have not been available. We used data from the western stream and river survey of the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program to estimate the surface area of flowing waters occupied by nonnative fish and amphibian species at three spatial scales. For the 12‐state survey area, an estimated 75% of the surface area of the target stream network had one or more nonnative fish or amphibian species, compared with 52% of the stream length. At all spatial scales (except the state of Washington), the estimates of the proportion of surface area with nonnatives were larger than those for estimated stream length. The relative extent of occupancy for individual species often differed depending on how they were assessed. For example, when assessed by length of network occupied, brook trout Salvelinus fontinalis was the most widespread nonnative fish (17%) but dropped to ninth position when assessed by surface area occupied (7%), while common carp Cyprinus carpio went from fourth position (10% of stream length) to second position when assessed by surface area occupied (27%). Estimates of the surface areas of flowing waters occupied by nonnative species are useful and easily calculated additions to the ways in which probability‐based surveys can assess the condition of the resource.

Testing the Hydrological Landscape Unit Classification System and Other Terrain Analysis Measures for Predicting Low-Flow Nitrate and Chloride in Watersheds

Elevated nitrate concentrations in streamwater are a major environmental management problem. While land use exerts a large control on stream nitrate, hydrology often plays an equally important role. To date, predictions of low-flow nitrate in ungauged watersheds have been poor because of the difficulty in describing the uniqueness of watershed hydrology over large areas. Clearly, hydrologic response varies depending on the states and stocks of water, flow pathways, and residence times. How to capture the dominant hydrological controls that combine with land use to define streamwater nitrate concentration is a major research challenge. This paper tests the new Hydrologic Landscape Regions (HLRs) watershed classification scheme of Wolock and others (Environmental Management 34:S71-S88, 2004) to address the question: Can HLRs be used as a way to predict low-flow nitrate? We also test a number of other indexes including inverse-distance weighting of land use and the well-known topographic index (TI) to address the question: How do other terrain and land use measures compare to HLR in terms of their ability to predict low-flow nitrate concentration? We test this for 76 watersheds in western Oregon using the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program and Regional Environmental Monitoring and Assessment Program data. We found that HLRs did not significantly improve nitrate predictions beyond the standard TI and land-use metrics. Using TI and inverse-distance weighting did not improve nitrate predictions; the best models were the percentage land use-elevation models. We did, however, see an improvement of chloride predictions using HLRs, TI, and inverse-distance weighting; adding HLRs and TI significantly improved model predictions and the best models used inverse-distance weighting and elevation. One interesting result of this study is elevation consistently predicted nitrate better than TI or the hydrologic classification scheme.

A new index of habitat alteration and a comparison of approaches to predict stream habitat conditions

Summary1. Stream habitat quality assessment complements biological assessment by providing a mechanism for ruling out habitat degradation as a potential stressor and provides reference targets for the physical aspects of stream restoration projects. This study analysed five approaches for predicting habitat conditions based on discriminant function, linear regressions, ordination and nearest neighbour analyses.2. Quantitative physical and chemical habitat and riparian conditions in minimally‐impacted streams in New Hampshire were estimated using United States Environmental Protection Agency's Environmental Monitoring and Assessment Program protocols. Catchment‐scale descriptors were used to predict segment‐scale stream channel and riparian habitat, and the accuracy and precision of the different modelling approaches were compared.3. A new assessment index comparing and summarizing the degree of correspondence between predicted and observed habitat based on Euclidean distance between the standardized habitat factors is described. Higher index scores (i.e. greater Euclidean distance) would suggest a greater deviation in habitat between observed conditions and expected reference conditions. As in most biotic indices, the range in index scores in reference sites would constitute a situation equivalent to reference conditions. This new index avoids the erroneous prediction of multiple, mutually exclusive habitat conditions that have confounded previous habitat assessment approaches.4. Separate linear regression models for each habitat descriptor yielded the most accurate and precise prediction of reference conditions, with a coefficient of variation (CV) between predictions and observations for all reference sites of 0.269. However, for a unified implementation in regions where a classification‐based approach has already been taken for biological assessment, a discriminant analysis approach, that predicted membership in biotic communities and compared the mean habitat features in the biotic communities with the observed habitat features, was similar in prediction accuracy and precision (CV = 0.293).5. The best model had an error of 27% of the mean index value for the reference sites, indicating substantial room for improvement. Additional catchment characteristics not readily available for this analysis, such as average rainfall or winter snow‐pack, surficial geological characteristics or past land‐use history, may improve the precision of the predicted habitat features in the reference streams. Land‐use history in New Hampshire and regional environmental impacts have greatly impacted stream habitat conditions even in streams considered minimally‐impacted today; thus as regional environmental impacts change and riparian forests mature, reference habitat conditions should be re‐evaluated.

Using Relative Risk to Compare the Effects of Aquatic Stressors at a Regional Scale

The regional-scale importance of an aquatic stressor depends both on its regional extent (i.e., how widespread it is) and on the severity of its effects in ecosystems where it is found. Sample surveys, such as those developed by the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP), are designed to estimate and compare the extents, throughout a large region, of elevated conditions for various aquatic stressors. In this article, we propose relative risk as a complementary measure of the severity of each stressor's effect on a response variable that characterizes aquatic ecological condition. Specifically, relative risk measures the strength of association between stressor and response variables that can be classified as either "good" (i.e., reference) or "poor" (i.e., different from reference). We present formulae for estimating relative risk and its confidence interval, adapted for the unequal sample inclusion probabilities employed in EMAP surveys. For a recent EMAP survey of streams in five Mid-Atlantic states, we estimated the relative extents of eight stressors as well as their relative risks to aquatic macroinvertebrate assemblages, with assemblage condition measured by an index of biotic integrity (IBI). For example, a measure of excess sedimentation had a relative risk of 1.60 for macroinvertebrate IBI, with the meaning that poor IBI conditions were 1.6 times more likely to be found in streams having poor conditions of sedimentation than in streams having good sedimentation conditions. We show how stressor extent and relative risk estimates, viewed together, offer a compact and comprehensive assessment of the relative importances of multiple stressors.

A More Cost-Effective Emap Benthic Macrofaunal Sampling Protocol

Benthic macrofaunal sampling protocols in the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP) are to collect 30 to 50 random benthic macrofauna [defined as animals retained on a 0.5 mm (East and Gulf Coasts, USA) or a 1.0 mm mesh sieve (West Coast, USA)] samples per reporting unit using a 0.044 m(2) (East and Gulf Coasts) or 0.1 m(2) (West Coast) grab. Benthic macrofaunal community conditions in the reporting unit are characterized by cumulative distribution functions (CDFs) on end points of interest, such as number of species (S), abundance (A), and Shannon-Wiener diversity (H'). An EMAP and a companion field study were conducted concurrently in Tillamook Bay (Oregon, USA) to compare the cost effectiveness of benthic macrofauna samples collected using the EMAP West Coast (0.1 m(2) x >or=7 cm deep, 1.0 mm mesh), a 0.01 m(2) x 5 cm deep, 1.0 mm mesh, and a 0.01 m(2) x 5 cm deep, 0.5 mm mesh sampling protocol. Cost was estimated in relative laboratory sample-processing time. Sampling protocols were judged equally effective for EMAP purposes if, after linear transformation to adjust for scale changes in end point distributions, their S, A, and H' CDFs were not significantly different. The 0.01 m(2) x 5 cm deep, 1.0 mm mesh sampling protocol was the most cost effective.

Assessing Water Clarity as a Component of Water Quality in Gulf of Mexico Estuaries

The U.S. Environmental Protection Agency Environmental Monitoring and Assessment Program (EMAP) uses water clarity as a water quality indicator for integrated assessments of coastal waters. After the publication of the first National Coastal Condition Report (USEPA, 2001c), the national water clarity reference value of 10% of ambient surface light at 1 m depth was reevaluated and modified to reflect expected differences in regional reference light conditions. These regional differences range from naturally turbid estuaries like those found in Mississippi and Louisiana to clear water estuaries expected to support extensive beds of submerged aquatic vegetation in, e.g., Florida and Tampa Bays. For the second National Coastal Condition Report, water clarity was assessed based on regional reference values (USEPA, 2004). Different regional water clarity reference values and data collection methods necessitated the development of a water clarity index based on light attenuation coefficients (k). This index incorporates regional reference conditions and is interchangeable with secchi depth and percent light transmission calculated from light meter measurements. Evaluation of the water clarity index shows that k values based on transmissivity at 1 m can be estimated from secchi depth measurements and successfully used as a surrogate for transmissivity calculated from light meter data. An approach for assessing water clarity in Gulf of Mexico estuaries using light meter data and secchi depth is presented.

Validation and Calibration of a Model Used to Reconstruct Historical Exposureto Polycyclic Aromatic Hydrocarbons for Use in Epidemiologic Studies

ObjectivesWe previously developed a historical reconstruction model to estimate exposure to airborne polycyclic aromatic hydrocarbons (PAHs) from traffic back to 1960 for use in case–control studies of breast cancer risk. Here we report the results of four exercises to validate and calibrate the model.MethodsModel predictions of benzo[a]pyrene (BaP) concentration in soil and carpet dust were tested against measurements collected at subjects’ homes at interview. In addition, predictions of air intake of BaP were compared with blood PAH–DNA adducts. These same soil, carpet, and blood measurements were used for model optimization. In a separate test of the meteorological dispersion part of the model, predictions of hourly concentrations of carbon monoxide from traffic were compared with data collected at a U.S. Environmental Protection Agency monitoring station.ResultsThe data for soil, PAH–DNA adducts, and carbon monoxide concentrations were all consistent with model predictions. The carpet dust data were inconsistent, suggesting possible spatial confounding with PAH-containing contamination tracked in from outdoors or unmodeled cooking sources. BaP was found proportional to other PAHs in our soil and dust data, making it reasonable to use BaP historical data as a surrogate for other PAHs. Road intersections contributed 40–80% of both total emissions and average exposures, suggesting that the repertoire of simple markers of exposure, such as traffic counts and/or distance to nearest road, needs to be expanded to include distance to nearest intersection.

Continuous Determination of Fine Particulate Matter Mass in the Salt Lake City Environmental Monitoring Project: A Comparison of Real-Time and Conventional TEOM Monitor Results

Fine particulate matter (PM2.5) mass was determined on a continuous basis at the Salt Lake City Environmental Protection Agency Environmental Monitoring for Public Awareness and Community Tracking monitoring site in Salt Lake City, UT, using three different monitoring techniques. Hourly averaged PM2.5 mass data were collected during two sampling periods (summer 2000 and winter 2002) using a real-time total ambient mass sampler (RAMS), sample equilibration system (SES)-tapered element oscillating microbalance (TEOM), and conventional TEOM monitor. This paper compares the results obtained from the various monitoring systems, which differ in their treatment of semivolatile material (SVM; particle-bound water, semivolatile ammonium nitrate, and semivolatile organic compounds). PM2.5 mass results obtained by the RAMS were consistently higher than those obtained by the SES-TEOM and conventional TEOM monitors because of the RAMS ability to measure semivolatile ammonium nitrate and semivolatile organic material but not particle-bound water. The SESTEOM monitoring system was able to account for an average of 28% of the SVM, whereas the conventional TEOM monitor loses essentially all of the SVM from the single filter during sampling. Occasional mass readings by the various TEOM monitors that are higher than RAMS results may reflect particle-bound water, which, under some conditions, is measured by the TEOM but not the RAMS.

U.S. NATIONAL RESPONSE ASSETS FOR RADIOLOGICAL INCIDENTS

The federal government has had the ability to respond to incidents of national significance for decades. Since 11 September 2001, there have been enhancements to existing federal assets and the creation of new federal assets. This presentation will provide an overview of the more significant federal assets. Pivotal to a response of national significance is the U.S. Department of Energy (DOE) Federal Radiological Monitoring and Assessment Center, which organizes and coordinates federal agency monitoring activities during an emergency. DOE manages the Federal Radiological Monitoring and Assessment Center during the emergency phase, and the Environmental Protection Agency (EPA) manages the response during the recovery phase once the emergency is terminated. EPA monitoring teams provide support during both the emergency and recovery phases of an emergency. Other DOE teams are available to respond to major nuclear power plant events, transportation accidents, or terrorism events involving the use of radiological materials, including the Radiological Assistance Program, the Aerial Measuring System, the National Atmospheric Release Advisory Center, and the Radiation Emergency Assistance Center/Training Site. For incidents involving a nuclear weapon, an improvised nuclear device, or a radiological dispersal device, DOE assets such as the Nuclear Emergency Support Team and the Accident Response Group could provide capabilities for weapon or device search, recovery, and removal. The Radiological Triage System harnesses the weapons scientists and engineers at the DOE national laboratories to provide gamma spectroscopy interpretation for agencies responding to an incident. In recent years, National Guard Weapons of Mass Destruction-Civil Support Teams have been created to support state and local response to terrorism events. The Civil Support Teams normally come under direct control of the state and can respond without requiring authorization from the U.S. Department of Defense (DoD). Changes brought about by the events of September 11 also extend to changing federal response policy and planning. Therefore, the Catastrophic Incident Response Annex to the National Response Plan is discussed. DoD also provides specifically designated radiological response capabilities that can be utilized within the guidelines of the National Response Plan. While optimally designed to support military missions, these resources also help provide for a well-equipped set of national assets to temporarily support and augment the local, state, and federal civil agencies that have primary authority and responsibility for domestic disaster assistance. The military's role in domestic emergencies is well defined in military regulations, as well as the national plan.

Evaluating methods for assessing sediment quality in a Great Lakes embayment

A probability-based, sediment quality assessment was conducted during 1995 in the lower St. Louis River Area of Concern, located in western Lake Superior. A regional application of the intensified sampling grid developed for the United States Environmental Protection Agency's Environmental Monitoring and Assessment Program was used to randomly select 90 sites for measuring the following sediment quality indicators: sediment chemistry, physical parameters, sediment toxicity, and benthic macroinvertebrate community structure. Screening methods were used to assess sediment chemistry and sediment toxicity at all sites, whereas more conventional metrics were used at a subset of sites. In addition, sediment quality data were collected from 20 a priori training sites, 10 in low impact areas and 10 in high impact areas. Mean probable effect concentration quotients were calculated for sediment chemistry variables at each site. As the range of mean probable effect concentration quotients values increased, the incidence of sediment toxicity increased. Benthic data from the training sites were used to establish standard criteria for developing two benthic integrity indices based on multimetric analysis and discriminant function analysis. Based on the training site results, the discriminant function analysis categorized the macroinvertebrate community at all random sites as 45 percent low impact and 55 percent high impact. A multimetric approach categorized 55 percent of the random sites as low impact and 36 percent as high impact. Due to the overlap of 95 percent confidence intervals, the multimetric approach also placed 9 percent of the random sites into an indeterminate category. The incidence of high impact sites appears to be primarily due to physical habitat characteristics. This finding was supported by the sediment quality triad assessment of 52 random sites that indicated alteration of the benthic community at 71 percent of sites was probably not due to chemical contamination.

Comparison of macroinvertebrate sampling methods for nonwadeable streams

Bioassessment of nonwadeable streams in the United States is increasing, but methods for these systems are not as well-developed as for wadeable streams. In this study, we compared six macroinvertebrate field sampling methods for nonwadeable streams adapted from those used by three major programs: the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program-Surface Waters, the U.S. Geological Survey's National Water Quality Assessment Program, and the Ohio Environmental Protection Agency, Division of Surface Water Biocriteria Program. We performed all six methods at 60 sites across four rivers and measured water chemistry and physical habitat at each site to assess abiotic conditon. Sites were divided into two groups: those influenced by navigational lock and dam structures (restricted flow, or RF) and those free-flowing or with lowhead dams (run-of-the-river, or ROR). Metrics based on passive Hester-Dendy artificial substrate samplers differed greatly from active sampling methods (i.e., using nets) but represented abiotic conditions well in both ROR and RF sites. Although metric values were similar across certain sampling methods, the metrics significantly correlated with abiotic variables varied among methods and between ROR and RF sites. These results emphasize that methods are not interchangeable, and the ability to detect certain stressors depends on sampling method.