Air quality measurements for the aerosol research and inhalation epidemiology study

Measurements of pollutant gases, airborne particulate matter mass and composition, and meteorology have been made at a core site near downtown Atlanta, GA, since August 1998 in support of the Aerosol Research and Inhalation Epidemiology Study (ARIES). This site is one of eight in the Southeastern Aerosol Research and Characterization network. The measurement objective is to provide a long-term, multivariate dataset suitable for investigating statistical associations of respiratory and cardiovascular disease with airborne particulate matter composition, meteorology, and copollutant gases through epidemiologic modeling. Measurements are expected to continue through 2010. Ancillary multiyear measurements at additional sites in the Atlanta metropolitan area and in short-term exposure assessments have been used to estimate the exposure/measurement error associated with using data from a central site to approximate human exposures for the entire area. To date, 13-, 25-, and 53-month air quality datasets have been used in epidemiologic analyses.     

Validation of the digital opacity compliance system under regulatory enforcement conditions

U.S. Environmental Protection Agency (EPA) Emission Measurement Center in conjunction with EPA Regions VI and VIII, the state of Utah, and the U.S. Department of Defense have conducted a series of long-term pilot and field tests to determine the accuracy and reliability of a visible opacity monitoring system consisting of a conventional digital camera and a separate computer software application for plume opacity determination. This technology, known as the Digital Opacity Compliance System (DOCS), has been successfully demonstrated at EPA-sponsored Method-9 "smoke schools", as well as at a number of government and commercially operated industrial facilities. Results from the current DOCS regulatory pilot study demonstrated that, under regulatory enforcement conditions, the average difference in opacity measurement between the DOCS technology and EPA Reference Method 9 (Method 9) was 1.12%. This opacity difference, which was computed from the evaluation of 241 regulated air sources, was found to be statistically significant at the 99% confidence level. In evaluating only those sources for which a nonzero visible opacity level was recorded, the     

The prevention of occupational injuries in two industrial plants using an incident reporting scheme

INTRODUCTION: The aim of this study was to examine whether the introduction of an incident reporting scheme with feedback in two industrial plants had an effect on the number of major incidents. METHOD: An intervention design with measurements before the implementation of the incident reporting scheme and two years later was used to examine the relationship between incident rates, safety climate, the willingness to report incidents and perceived management commitment to safety. RESULTS: The results showed that a successful implementation of an incident reporting scheme was followed by a decline in the incidence of major incidents at a Danish metal plant. A key factor in implementing the scheme was top management commitment, which was lacking at another plant, where the implementation of a similar scheme failed. CONCLUSION: Although the study shows some encouraging results concerning the use of incident reporting schemes to prevent occupational accidents, the possibility to draw causal conclusions is limited in the present study, and further studies are needed before the effectiveness of such schemes can be evaluated with certainty.     

Field demonstration of visible opacity photographic systems

The Digital Opacity Compliance System (DOCS) is an innovative method that uses digital imaging technology to quantify visible opacity of stationary sources. DOCS, which has been demonstrated at pilot and full scale as a technically defensible and economically attractive alternative to U.S. Environmental Protection Agency (EPA) Reference Method 9 (Method 9), uses commercial-off-the-shelf (COTS) digital cameras in combination with a user-friendly computer software package to determine opacity. To date, all DOCS field testing has been conducted using two models of digital cameras, notably, Kodak Models DC265 and DC290, both of which are no longer commercially available. To ensure that field-validated digital cameras will be available to future DOCS users, a suite of new digital cameras was evaluated with the opacity determination software including the following: (1) Sony Model Cybershot Model DSC-WI, (2) Nikon Model Coolpix 5200, (3) Fuji Finepix Model E500, and (4) Kodak Model DX6490. Within the opacity range of regulatory interest, that is, 0-40%, the Sony Cybershot Model DSC-WI and Nikon Coolpix Model 5200 digital cameras were found to generate plume photographs of which the DOCS opacity analysis yielded results that were statistically equivalent to the previously field-validated Kodak Model DC290. In contrast, the Fuji Finepix Model E500 generated plume photographs of which the DOCS opacity analysis were, on average, 2.2% less than those generated by the Kodak Model DC290 photographs, a difference that was determined to be statistically significant. Over the same opacity range, photographs taken by the Kodak Model DX6490 yielded DOCS opacity readings that were found to be statistically equivalent to a Method 9-certified transmissometer. Based on the results from the current digital camera validation testing approach, EPA has developed a new camera-based visible opacity measurement method titled "Determination of Visible Emission Opacity from Stationary Sources Using Computer-Based Photographic Analysis Systems." The proposed method is expected to be promulgated after closure of the public comment period.     

A comparison of amniotic fluid alpha-fetoprotein and acetylcholinesterase in the prenatal diagnosis of open neural tube defects and anterior abdominal wall defects

Amniotic fluid samples received for routine prenatal diagnosis of open neural tube defects were used for a study to compare amniotic fluid acetylcholinesterase (AChE) determination using a monoclonal antibody (4F19) enzyme antigen immunoassay and amniotic fluid alpha-fetoprotein (AFP) measurement as diagnostic tests for open neural tube defects. The study was based on 9964 women with singleton pregnancies and known outcome (including 6 with anencephaly and 18 with open spina bifida) having an amniocentesis at 14–23 weeks of gestation. The AChE immunoassay yielded detection rates for anencephaly of 100 per cent (95 per cent confidence interval (CI) 54·07–100 per cent), for open spina bifida of 100 per cent (95 per cent CI 81·47–100 per cent), for anterior abdominal wall defects of 20 per cent (95 per cent CI 0-51-71-64 per cent), and a false-positive rate of 0·22 percent (95 per cent CI 0·14–0·34 per cent) excluding anencephaly, open spina bifida, and anterior abdominal wall defects. For similar detection rates the false-positive rate of the AFP test was significantly higher, 0·74 per cent (95 per cent CI 0·58–0·94 per cent). On the basis of these findings, it is recommended that the technically simple AChE immunoassay should be used on all samples; the AFP test should only be used on the 0·5 per cent of the samples with concentrations of AChE activity ⩾ 8·5 nkat/1 for clear samples and blood-stained samples becoming clear after centrifugation, and ⩾ 25·0 nkat/1 for blood-stained samples that are discoloured after centrifugation; an AFP cut-off level of 2·0 MOM is recommended for this policy. Thereby, the detection rates for anencephaly, open spina bifida, and anterior abdominal wall defects would be 100, 100, and 20 per cent, respectively (95 per cent CIs 54·07–100, 81·47–100, and 0·51–71·64 per cent, respectively), and the false-positive rate would be 0·08 per cent (95 per cent CI 0·03–0·16 per cent) (excluding anencephaly, open spina bifida, and anterior abdominal wall defects).     

Selenium Bioaccumulation in Stocked Fish as an Indicator of Fishery Potential in Pit Lakes on Reclaimed Coal Mines in Alberta, Canada

Pit lakes are a common reclamation strategy for open pit mines; however, there is a concern about their water quality and suitability as fish habitat because they are often contaminated by metals or metalloids. This study assessed the exposure of fish and invertebrates to selenium (Se) and other metals and metalloids in pit lakes formed by open pit coal mining in Tertiary (thermal coal) and in Cretaceous (metallurgical coal) bedrock. Juvenile hatchery rainbow trout, Oncorhynchus mykiss, and brook trout, Salvelinus fontinalis, were stocked into two thermal coal pit lakes (water Se < 2 μg/L, low water Se) and two metallurgical coal pit lakes (water Se > 15 μg/L, high water Se). Se accumulation in stocked fish and concentrations in invertebrates were characterized over a period of 2 years. In the metallurgical pits, invertebrates had higher Se concentrations and fish accumulated Se to higher levels (exceeding USEPA tissue Se guidelines) than biota in the thermal pits. Rainbow and brook trout accumulated similar concentrations of Se in their muscle and exhibited a similar relationship between whole-body and muscle Se concentrations. These results may be used by resource managers to assess compliance with whole-body tissue Se guidelines and to determine if pit lakes in coal mining areas pose a significant Se risk to wildlife or human health. The high Se exposure in metallurgical coal pits indicates that under the current mining and reclamation strategy, these lakes are not suitable for management as recreational “put and take” fisheries.     

Surface ozone-temperature relationships in the eastern US: A monthly climatology for evaluating chemistry-climate models

We use long-term, coincident O₃ and temperature measurements at the regionally representative US Environmental Protection Agency Clean Air Status and Trends Network (CASTNet) over the eastern US from 1988 through 2009 to characterize the surface O₃ response to year-to-year fluctuations in weather, for the purpose of evaluating global chemistry-climate models. We first produce a monthly climatology for each site over all available years, defined as the slope of the best-fit line (m_O3-T) between monthly average values of maximum daily 8-hour average (MDA8) O₃ and monthly average values of daily maximum surface temperature (T_max). Applying two distinct statistical approaches to aggregate the site-specific measurements to the regional scale, we find that summer time m_O3-T is 3–6 ppb K^?1 (r = 0.5–0.8) over the Northeast, 3–4 ppb K^?1 (r = 0.5–0.9) over the Great Lakes, and 3–6 ppb K^?1 (r = 0.2–0.8) over the Mid-Atlantic. The Geophysical Fluid Dynamics Laboratory (GFDL) Atmospheric Model version 3 (AM3) global chemistry-climate model generally captures the seasonal variations in correlation coefficients and m_O3-T despite biases in both monthly mean summertime MDA8 O₃ (up to +10 to +30 ppb) and daily T_max (up to +5 K) over the eastern US. During summer, GFDL AM3 reproduces m_O3-T over the Northeast (m_O3-T = 2–6 ppb K^?1; r = 0.6–0.9), but underestimates m_O3-T by 4 ppb K^?1 over the Mid-Atlantic, in part due to excessively warm temperatures above which O₃ production saturates in the model. Combining T_max biases in GFDL AM3 with an observation-based m_O3-T estimate of 3 ppb K^?1implies that temperature biases could explain up to 5–15 ppb of the MDA8 O₃ bias in August and September though correcting for excessively cool temperatures would worsen the O₃ bias in June. We underscore the need for long-term, coincident measurements of air pollution and meteorological variables to develop process-level constraints for evaluating chemistry-climate models used to project air quality responses to climate change.     

Multivariate statistical characterization of water quality in Lake Lanier, Georgia, USA

Watershed monitoring programs depend on water quality characterization data collected for many parameters, at many times and places, and with limited resources. Our objective is to present a strategy that reduces the measured parameters, locations, and frequency without compromising the quality of the monitoring program. One year of twice-monthly (growing season) and monthly (dormant season) water quality data collected from 17 lake and 10 tributary sites are used in conjunction with multivariate statistical techniques to improve the utility of collected data by identifying key parameters and monitoring locations. Factor analysis shows that tributary water quality data consists of three components-stormwater runoff, municipal and industrial discharges, and ground water-which can be distinguished using total suspended solids, total dissolved solids, and alkalinity plus soluble reactive P, respectively. Lake water quality characterization is more ambiguous than tributary water quality characterization, but factor analysis indicates that anoxia associated with lake stratification is the largest source of lake water quality variation, followed by nutrient abundance, and finally by biomass abundance. Cluster analysis suggests that tributary and lake monitoring stations can be consolidated. Reducing the number of parameters and stations frees up resources for increased monitoring elsewhere.     

Treatment of creosote-contaminated groundwater in vegetated sorption/bio-barriers in cold climates

Permeable barriers are structures installed in situ to treat contaminated groundwater. Pollutants are removed as contaminated groundwater flows through a barrier material. A compost/sand barrier and a plant covered permeable barrier with soil/sand and peat/sand were tested in pilot-scale to treat creosote-contaminated groundwater by sorption and biological removal in situ. Outlet concentrations of the barriers were consistently low during the 29 months of operation. Although sorption sites were filled up with polycyclic aromatic hydrocarbons, they seemed to be regenerated because of biodegradation under aerobic conditions. The vegetated section was least efficient, probably because of lack of oxygen, hence it could not be determined if the plants had a positive effect. As long as biodegradation is efficient the barrier is expected to function for several more years.