Analysis of the Atmosphere for Light Hydrocarbons

A procedure has been developed for the analysis of trace quantities of light hydrocarbons in air. A freezetrap filled with chromatographic packing was installed in place of the gas sample loop of a flame ionization chromatograph. An air sample 0.1–0.5 liter volume was passed through the trap which was chilled with liquid oxygen. The trap wasthen brought to ice temperature and its contents simultaneously swept into the column. The resulting chrómatogram could be used to determine about 25 hydrocarbons through n-hexane. The minimum detectable concentration was below 1 ppb for these hydrocarbons. With such sensitivity it is possible to make useful measurements even on samples of light air pollution. Air samples from the Riverside area were analyzed in this fashion starting in the summer of 1965. The relative amounts of these hydrocarbons were then compared with the distribution reported for the various known hydrocarbon sources. The attenuation of the more reactive hydrocarbons by photolysis was also observed. A system for irradiating trapped air samples was also constructed. Samples were collected in 5-gallon borosilicate bottles which were then irradiated with ultraviolet radiation and the concentration changes followed.     

A Damaging Explosion of Peroxyacetyl Nitrate

A damaging explosion of the smog component peroxyacetyl nitrate (PAN) was traced to the presence of liquid PAN in a pressure gauge and pipe fitting attached to the metal container. Some of the PAN vapor had condensed while stored in a cold room at about 0°C over a weekend. Recommendations for avoiding a repetition of this accident are given.     

Product Guide/1988

Investigation, mitigation, and clean-up of hazardous materials at Superfund sites normally requires on-site workers to perform hazardous and sometimes potentially dangerous functions. Such functions include site surveys and the reconnaissance for airborne and buried toxic environmental contaminants. Airborne contaminants of concern usually emanate from spilled materials and require monitoring the air at the perimeter and throughout the clean-up site to ascertain the extent of contamination. Buried contaminants of major concern are often the result of leaking underground drums containing toxic wastes and require "reconnaissance excavations" to determine their location. Workers conducting on-site air monitoring risk dermal, ocular and inhalation exposure to hazardous chemicals, while those performing excavations also risk the potential exposure to fire, explosion, and other physical injury. EPA's current efforts to protect its workers and mitigate these risks include the use of robotic devices. Using robots offers the ultimate in personnel protection by removing the worker from the site of potential exposure, especially during site investigations, when there is almost always a certain encounter with unknown chemical wastes having unknown toxicity.

This paper describes the demonstration of a commercially-available robotic plat form modified and equipped for air monitoring and the ongoing research for the development of a ground penetrating radar (GPR) system to detect buried chemical waste drums. These robotic devices can ultimately be routinely deployed in the field for the purpose of conducting inherently safe reconnaissance activities during Superfund / SARA remedial operations.     

Wetfall Deposition and Precipitation Chemistry for a Central Appalachian Forest

Abstract

Although extensive research on acidic deposition has been directed toward spruce-fir forests, less research has been done on the impacts of air pollution on eastern montane hardwood forests. The purpose of this study was to describe precipitation chemistry for several Appalachian hardwood forest sites at or near the Fernow Experimental Forest (FEF) to assess the potential for problems associated with acidic deposition. Emphasis was placed on seasonal patterns of ionic concentrations (H+, Ca++, NH4+; NO3-, and SO4=) and spatial variability of ionic concentrations and deposition among sites. Seasonal patterns of most ions showed highest concentrations during the summer months and deposition of H+ was especially pronounced during this time. Deposition of all ions was generally greater (related to greater precipitation) at three montane forested sample sites compared to a nonforested riverbottom site. Precipitation chemistry at FEF was similar to other sites throughout the eastern United States and contrasted sharply with mid-western and western sites. Eastern sites, including means for FEF sites, were uniformly 3-4 times higher in H+ and SO4= concentration than the mid-western and western sites. Precipitation at FEF was chronically acidic, more so during the growing season, and highest at higher elevations where environmental stresses can be most severe. Furthermore, there were occasional large discrepancies between the low-elevation site and the higher-elevation forested sites for precipitation chemistry and acidic deposition. These results suggest that synoptic-scale (network) data may greatly underestimate the pollutant conditions to which highelevation forest trees are exposed, since network data rarely take elevation into account and typically are based on annual ionic concentration and deposition means that may be considerably lower than those of the growing season.     

Declining populations of freshwater pearl mussels (Margaritifera margaritifera) are burdened with heavy metals and DDT/DDE

Many aquatic mollusks, such as the freshwater pearl mussel (Margaritifera margaritifera), are in decline throughout Europe. The reasons are largely unknown; factors that have been suggested to contribute are river bed compaction due to agricultural practices, eutrophication, or pollutants of various natures. Brittle shells of recently deceased pearl mussels from northern Bavaria with weak calcium incrustations point to the possibility that calcium metabolism is affected. It is known that certain persistent organic pollutants and some heavy metals may induce calcium deficiency in wildlife. Elevated levels of the organochlorine insecticide DDT and its metabolite DDE, as well as of cadmium and some other heavy metals, have been found in pearl mussels. Both classes of environmental pollutants are known to potentially interfere with calcium homeostasis.     

Residues of organochlorine pesticides in near shore waters of LaiZhou Bay and JiaoZhou Bay, Shandong Peninsula, China

The extent of organochlorine pesticides (OCPs) contamination in coastal waters around LaiZhou Bay and JiaoZhou Bay in Shandong Peninsula, northern China, was investigated. The areas around the two bays are both densely populated, thrive with intensive agriculture and industrial activities. Multi-techniques including GC-MS, GC-muECD coupled with chemical peak confirmation and strict QC procedures were used for the quantitative determination of 15 OCPs including alpha, beta, gamma and delta isomers of hexachlorocyclohexane (HCH), pentachloronitrobenzene (PCNB), heptachlor, aldrin, endosulfan, p,p'-DDE, dieldrin, endrin, p,p'-DDD, o,p'-DDT, p,p'-DDT and methoxychlor. The survey results show that contaminations by OCP residues remain widespread in the areas, but the averaged concentration levels are all below the regulatory limits, e.g., CMC limits (acute criterion values) specified in US Environmental Protection Agency (USEPA) and China national standards. Average concentration of OCPs in water samples were from undetectable to 3.8 ng l(-1) in LaiZhou Bay and from 0.1 to 3.9 ng l(-1) in JiaoZhou Bay, respectively. A comparison between the current and historical data shows a rapidly decreasing trend of OCPs over the past twenty years in the study areas.     

Chemical Characteristics and Source Implications of Petroleum Hydrocarbon Contaminants in the Sediments near Major Drainage Outfalls along the Coastal of Laizhou Bay, Bohai Sea, China

The associated industrial and urban developments are located to a large extent along the Laizhou Bay, Bohai Sea coastal and raw sewage is often discharged into near shore waters with little treatment. To find out chemical characteristics and pollution source of the petroleum related contaminations in sediments near the major drainage outfalls located in the coastal, in this study, 10 surface sediment samples were collected during June. Sediment samples were extracted by organic solvents, separated by silica gel column chromatography and the concentrations and the profiles of n-alkane, biomarker and PAH in sediments were analyzed by gas chromatography-mass selective detector (GC-MSD). The use of several molecular markers and related indexes derived for n-alkane and PAHs has been proposed for assessing the relative contributions to the environment of hydrocarbon sources. As a result, n-alkanes reflect that the sea area of paper mill (Station ZZ08) is dominated by vascular plant. DY petroleum oil field and outer shore of the paper mill (Station ZZ02) have some degrees of petroleum related hydrocarbon contamination. Whereas the contamination of the sea area of TH River may be ascribed to different sources such as territorial non-point pollution source, domestic sewages, and stormwater runoff. Judged by their PAH ratios, the sediments near the paper mill (Station ZZ02) and the outer station of the oil field (Staion TH2) were pyrolytic. The estuary of Tiao River including the inner Station THX, TH10 and TH05 are petrogenic. The marine sediment near DY drainage outfall may have a mixture source of PAH both pyrolytic and petrogenic.