Evaluation of performance reference compounds in polyethylene-based passive air samplers

Polyethylene-based passive air samplers (PSDs) were loaded with performance reference compounds (PRCs) and deployed in a wind tunnel to examine the effects of wind speed on sampler performance. PRCs could be loaded reproducibly into PSDs, with coefficients of variation only exceeding 20% for the more volatile compounds. When PSDs were exposed to low (0.5-1.5 m s-1) and high (3.5-4.5 m s-1) wind speeds, PRC loss rate constants generally increased with increasing wind speed and decreased with increasing sampler/air partition coefficients. PSD-based air concentrations calculated using PRC loss rate constants and sampler/air partition coefficients and air concentrations measured using active samplers compared closely. PRCs can be used to account for the effect of differences in wind speeds on sampler performance and measure air concentrations with reasonable accuracy.     

Nonfatal injuries following Hurricane Katrina--New Orleans, Louisiana, 2005

The Journal of Safety Research has partnered with the National Center for Injury Prevention and Control at the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, USA, to briefly report on some of the latest findings in the research community. This report is the fourth edition in a series of CDC articles. BACKGROUND: An active injury and illness surveillance system was established by the Centers for Disease Control and Prevention (CDC) along with the Louisiana Department of Health and Hospitals (LDHH) in the aftermath of Hurricane Katrina in functioning hospitals and medical clinics. RESULTS: The surveillance system recorded 7,543 nonfatal injuries among residents and relief workers between September 8-October 14, 2005. The leading mechanisms of injury identified in both groups were fall and cut/stab/pierce, with a greater proportion of residents compared to relief workers injured during the repopulation period. Clean-up was the most common activity at the time of injury for both groups. CONCLUSION: Injuries documented through this system underscore the need for surveillance of exposed populations to determine the injury burden and initiate injury prevention activities and health communication campaigns.     

Comparison of two winter air quality episodes during the California Regional Particulate Air Quality Study

The duration, strength, spatial extent, and chemical makeup of particulate matter (PM) are compared for two winter air quality episodes captured during the California Regional Particulate Air Quality Study (CRPAQS). Each episode, from the beginning of the buildup through dissolution, lasted about 3 weeks. The first episode occurred from December 14, 1999, through January 1, 2000, with peak 24-hr average fine particulate matter (PM2.5) concentrations reaching 129 microg/m3. The second episode occurred a year later, from December 18, 2000, through January 8, 2001, with peak 24-hr average PM2.5 concentrations reaching 179 microg/m3. Although similar in duration, each episode exhibited unique characteristics. One significant difference was the episode buildup rate; rapid in 1999, but slow and steady in 2000. The rapid buildup of the first episode resulted in more days with PM2.5 concentrations above the 24-hr federal standard, whereas the slow and steady increase of the second episode produced higher peaks. Spatial extent and progress also differed between the two episodes. The Northern Valley was impacted more during the December 1999 episode, and the Southern Valley during the December 2000 episode. The differences carried over into chemical composition. Ammonium nitrate dominated the PM2.5 mass during the December 1999 episode. The second episode reflected a dichotomy typical to the San Joaquin Valley, with Fresno concentrations dominated by organic and elemental carbon and the rest of the Valley concentrations dominated by ammonium nitrate. Each episode showed a regional as well as a local component. Ammonium nitrate concentrations, which result from more regional-scale secondary formation and mixing of emissions, were fairly uniform among the urban and rural sites. Carbon concentrations were always higher at urban sites than at rural sites, corresponding to the higher emissions density of primary carbon sources in urban areas.     

Ground water stratification and delivery of nitrate to an incised stream under varying flow conditions

Ground water processes affecting seasonal variations of surface water nitrate concentrations were investigated in an incised first-order stream in an agricultural watershed with a riparian forest in the coastal plain of Maryland. Aquifer characteristics including sediment stratigraphy, geochemistry, and hydraulic properties were examined in combination with chemical and isotopic analyses of ground water, macropore discharge, and stream water. The ground water flow system exhibits vertical stratification of hydraulic properties and redox conditions, with sub-horizontal boundaries that extend beneath the field and adjacent riparian forest. Below the minimum water table position, ground water age gradients indicate low recharge rates (2-5 cm yr(-1)) and long residence times (years to decades), whereas the transient ground water wedge between the maximum and minimum water table positions has a relatively short residence time (months to years), partly because of an upward increase in hydraulic conductivity. Oxygen reduction and denitrification in recharging ground waters are coupled with pyrite oxidation near the minimum water table elevation in a mottled weathering zone in Tertiary marine glauconitic sediments. The incised stream had high nitrate concentrations during high flow conditions when much of the ground water was transmitted rapidly across the riparian zone in a shallow oxic aquifer wedge with abundant outflow macropores, and low nitrate concentrations during low flow conditions when the oxic wedge was smaller and stream discharge was dominated by upwelling from the deeper denitrified parts of the aquifer. Results from this and similar studies illustrate the importance of near-stream geomorphology and subsurface geology as controls of riparian zone function and delivery of nitrate to streams in agricultural watersheds.     

Education and Changes in Residential Nonpoint Source Pollution

Urban areas contribute pollutants such as excess nitrogen and bacteria to receiving water bodies. The objective of this project was to determine if stormwater quality could be improved by educating homeowners and implementing best management practices (BMPs) in a suburban neighborhood. The paired watershed design was used, where a control and treatment watershed are monitored during a calibration and treatment period. Treatment consisted of the education of homeowners and structural changes designed to minimize nonpoint pollution. Some changes in measured behavior were reported. According to the treatment period survey, 11% of respondents in the treatment watershed began fertilizing their lawn based on the results of a soil test, whereas none had done so previously. In addition, 82% of respondents in the treatment watershed stated that they left clippings on the lawn compared to 62% from the initial survey. Twelve of 34 lots (35%) adopted some BMPs following education efforts, indicating a significant (P = 0.001) increase in BMP use overall. However, a χ² analysis of survey data indicated no significant changes in measured behavior with regard to specific questions. Analysis of covariance (ANCOVA) results indicated that a 75% reduction in nitrite + nitrate - N (change in intercept, P = 0.001) and a 127% reduction in fecal coliform bacteria (change in slope, P = 0.05) concentrations occurred. However, the treatment period regression was nonsignificant for bacteria. Total nitrogen, total phosphorus, and ammonia-N concentrations did not change significantly. Intensive education efforts produced BMP implementation and measurable water quality improvements.     

Risk perception research: socio-cultural perspectives on the public experience of air pollution

This paper reviews recent work in the field of risk perception research, taking its examples primarily from work relating to air pollution issues. The paper opens with a brief discussion of the psychological literature on risk perception, in order to set out the key insights, criticisms and more recent developments associated with such approaches, before turning to the findings of recent socio-cultural analyses of perceptions of air pollution. This account, which considers how social and cultural factors influence the way in which people interpret and make sense of risk, draws linkages with psychological risk perception research, revealing that over the last decade there has been a pronounced degree of convergence between the conclusions being reached across these two (historically disparate) fields of research. The paper concludes by evaluating the relevance of risk perception research for the science and policy of risk assessment and management.     

Rodents as receptor species at a tritium disposal site

New methods are being employed on the Department of Energy's Savannah River Site to deal with the disposal of tritium, including the irrigation of a hardwood/pine forest with tritiated water from an intercepted contaminant plume to reduce concentrations of tritium outcropping into Fourmile Branch, a tributary of the Savannah River. The use of this system has proven to be an effective means of tritium disposal. To evaluate the impact of this activity on terrestrial biota, rodent species were captured on the tritium disposal site and a control site during two trapping seasons in order to assess tritium exposure resulting from the forest irrigation. Control site mice had background levels of tritium, 0.02 Bq/mL, with disposal site mice having significantly higher tritium concentrations, mean=34.86 Bq/mL. Whole body tritium concentrations of the mice captured at the disposal site were positively correlated with tritium application and negatively correlated with precipitation at the site.     

Biotic and abiotic degradation of CL-20 and RDX in soils

The caged cyclic nitramine 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) is a new explosive that has the potential to replace existing military explosives, but little is known about its environmental toxicity, transport, and fate. We quantified and compared the aerobic environmental fate of CL-20 to the widely used cyclic nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in surface and subsurface soil microcosms. Soil-free controls and biologically attenuated soil controls were used to separate abiotic processes from biologically mediated processes. Both abiotic and biological processes significantly degraded CL-20 in all soils examined. Apparent abiotic, first-order degradation rates (k) for CL-20 were not significantly different between soil-free controls (0.018 < k < 0.030 d(-1)) and biologically attenuated soil controls (0.003 < k < 0.277 d(-1)). The addition of glucose to biologically active soil microcosms significantly increased CL-20 degradation rates (0.068 < k < 1.22 d(-1)). Extents of mineralization of (14)C-CL-20 to (14)CO(2) in biologically active soil microcosms were 41.1 to 55.7%, indicating that the CL-20 cage was broken, since all carbons are part of the heterocyclic cage. Under aerobic conditions, abiotic degradation rates of RDX were generally slower (0 < k < 0.032 d(-1)) than abiotic CL-20 degradation rates. In biologically active soil microcosms amended with glucose aerobic RDX degradation rates varied between 0.010 and 0.474 d(-1). Biodegradation was a key factor in determining the environmental fate of RDX, while a combination of biotic and abiotic processes was important with CL-20. Our data suggest that CL-20 should be less recalcitrant than RDX in aerobic soils.     

The EU-project ERAPharm. Incentives for the further development of guidance documents?

- Triggered by the detection of a large variety of pharmaceuticals in surface waters, soils and groundwaters across the world (e.g. Halling- Sørensen et al. 1998, Daughton & Ternes 1999, Jones et al. 2001, Heberer 2002) and the widespread occurrence of endocrine active compounds and related effects in the environment (e.g. Purdom et al. 1994, Tyler et al. 1998, Vethaak et al. 2002), pharmaceuticals in the environment have become an issue for both the scientific and the public community. During the last few years, our understanding of the fate and effects of pharmaceuticals in the environment has progressed significantly. However, there are still a number of uncertainties concerning the effects of pharmaceuticals on the environment and the assessment of potential exposure (e.g. Hanisch et al. 2004, Salomon 2005). These uncertainties will be addressed by the EU-project ‘Environmental risk assessment of pharmaceuticals’ (ERAPharm). This project, a specific targeted research project, is carried out within the priority ‘Global change and ecosystems’ of the 6th framework programme of the European Union. ERAPharm has started on 1st October 2004; the project duration is three years.     

Enhanced attenuation: Its place in the remediation of chlorinated solvents

The development and regulatory acceptance of monitored natural attenuation (MNA) as a remedial strategy has forever changed the field of environmental cleanup. MNA is continuing to develop but it is challenged by a lack of a clear definition for the appropriate application of the MNA strategy. This challenge has resulted in the lack of a significant record of restoration and site closure. Environmental professionals face challenges in providing guidance that addresses how to manage these sites when technologies, performance monitoring, and even environmental conditions are subject to further development, refinement, and/or altered perspectives. As our experience and institutional knowledge grows around the implementation of MNA, we have the opportunity to develop “second‐generation” management tools and procedures for optimizing sites utilizing MNA as a part of a comprehensive site management plan. This opportunity is the focus of the Enhanced Attenuation: Chlorinated Organics (EACO) Team of the Interstate Technology Regulatory Council (ITRC). The development of the “second‐generation” tools/procedures has included defining EA and evaluating, through the use of a national survey of state regulators, the experience with MNA and interest in EA. The results of these two efforts formed the basis for developing a framework that provides a “bridge” from active treatment to MNA. © 2007 Wiley Periodicals, Inc.