Monitoring atmospheric concentrations

The second factor is the temporal variation in concentrations in different ecosystem compartments. For example, sediments and prey fish exhibit less temporal variation in mercuiy concentration than do air or water, and thus statistically valid estimates of their status can be collected with less frequent monitoring (e.g., annual sampling for prey fish vs. daily or hourly sampling for atmospheric concentrations of mercury). 

Upon completion of the one hour agitation the decon mixture will be adjusted to a pH between 10 and 11. Conduct general area monitoring to confirm that the atmospheric concentrations do not exceed the airborne exposure limits (See Sections II and VIII). 

After sealing the head, the exterior of the drum shall be decontaminated and then labeled IAW EPA and DOT regulations. All leaking containers shall be overpacked with vermiculite placed between the interior and exterior containers. Decontaminate and label IAW EPA and DOT regulations. Dispose of the material IAW waste disposal methods provided below. Dispose of material used to decontaminate exterior of drum IAW Federal, state and local regulations. Conduct general area monitoring with an approved monitor (see Section VIII) to confirm that the atmospheric concentrations do not exceed the airborne exposure limit (see Sections II and VIII). 

Zwart et al. (1990) exposed groups of five male and five female Wistar rats to phosgene at varying concentrations for 5, 10, 30, or 60 min. The test atmosphere was monitored at both the inlet and outlet of the glass exposure chambers by gas chromatography and infrared analysis. The 10-min LC50 value was 80 ppm, and the 30-and 60-min LC50 values were 20 and 12 ppm, respectively. 

The odor threshold, 0.58 ppm to 5.0 ppm (Amoore and Hautala 1983 Ruth 1986) is low compared with irritant or toxic concentrations. No acute exposures were located resulting in mild effects in humans. Three monitoring studies, involving no symptoms to mild symptoms during chronic occupational exposures of adult males, are relevant to development of AEGL-1 values. The symptoms and blood concentrations of cyanide in the monitoring study of Chandra et al. (1980) indicate that the workers may have been exposed at higher atmospheric concentrations than those reported. 

Huege et al. [271] cultivated Arabidopsis plants in 13C02 atmosphere, transferred the plants to normal atmosphere, and monitored the dilution of isotopes in several metabolite pools. Through evaluation of the mass isotopomer distribution, metabolite partitioning processes could be monitored. However, due to the lack of absolute metabolite concentrations, no absolute fluxes could be calculated. Nevertheless, building upon this method, suitable approaches for flux analysis in autotrophic tissue might be derived in the future. 

No information was found on atmospheric concentrations of chlordecone other than historic monitoring data from samples collected in the vicinity of the manufacturing site. Chlordecone has been monitored in surface waters, particularly during the period shortly before and after production was terminated. In 1977, chlordecone was detected in surface water samples from the James River at low concentrations (less than 10 ng/L [ppt]), although it was not detected in more recent monitoring studies. The highest concentrations of this compound are found in sediments, principally in the James River where it had accumulated after the deposition of particulate matter to which the chlordecone was bound. In 1978, chlordecone was detected in sediments from the James River below its production site at concentrations in the mg/kg (ppm) range. 

Clark Al, McIntyre AE, Perry R, et al. 1984. Monitoring and assessment of ambient atmospheric concentrations of aromatic and halogenated hydrocarbons at urban, rural, and motorway locations. Environmental Pollution (Series B) 7 141-158. 

This review begins with a summary of the sources of monitoring data operated primarily by public agencies. The spatial and temporal patterns of oxidant concentrations are then discussed—urban versus rural and indoor versus outdoor relationships, diurnal and seasonal patterns, and long-term trends. The chapter includes brief discussions of photochemical oxidants other than ozone and of data quality and concludes with a set of recommendations for guidelines in future monitoring of atmospheric concentrations of ozone and other photochemical oxidants. 

Diazinon concentrations in the atmosphere were monitored in several national studies during the 1970s and 1980s and more recently in several regional studies. Diazinon has been measured in outdoor air samples in both rural and urban environments, near production facilities, and in indoor air (associated with its use for pest control in domestic and commercial buildings). 

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