Gas chromatographic analysis of trace hydrocarbon pollutants in water samples

Abstract

A stripping technique has been used to cencentrate selected hydrocarbons present in water samples at the parts per billion level for analysis by gas chromatography. The chromatograms of hydrocarbons thus stripped from several different water samples show similarities. Washing out of atmospheric pollutants by rainfall is postulated as an explanation of these results. This hypothesis is supported by a comparison of the data with those for trace atmospheric analysis. The comparison shows that the same compounds are present in similar relative amounts both in water samples and the atmosphere. After a period of rain the atmospheric concentrations decrease whilst the water bound concentrations increase.

ATSDR evaluation of potential for human exposure to benzene

“…Benzene levels measured in coastal surface waters of the Gulf of Mexico were 6 ng/kg (6 ppt) in relatively unpolluted waters and 50-175 ng/kg (50-175 ppt) in polluted coastal waters (Sauer, 1981). Benzene has been detected in rainwater in the United Kingdom at a concentration of 87.2 ppb (Colenutt and Thorburn, 1980).…”

“…Other acceptable methods include portable direct reading instruments and real-time continuous monitoring systems; these methods generally have a sensitivity in the ppm range. The most frequently used analytical methods for water samples containing benzene are GC/MS, GC/FID, and GC/PID (Blanchard and Hardy, (1986); Colenutt and Thorburn (1980);DOI, 1984;EPA, 1984EPA, , 1992Hammers and Bosman, 1986;Harland, et al, 1985;Lysyj, et al, 1980;Michael, et al, 1988;Pereira and Hughes, 1980;Sporstøl, et al, 1985). Benzene is usually isolated from aqueous media by the purge-and-trap method (Brass, et al, 1977;Colenutt and Thorburn (1980);DOI, 1984;EPA, 1979EPA, , 1984EPA, , 1992Hammers and Bosman, 1986;Harland, et al, 1985;Michael, et al, 1988).…”

“…The purged benzene is trapped on an adsorbent substance, such as Tenax GC or activated charcoal, and thermally desorbed. Recovery, where reported, ranges from acceptable (≈70%) (EPA, 1979(EPA, , 1984Michael, et al, 1988) to very good (≥90%) (Colenutt and Thorburn (1980); EPA, 1984EPA, , 1992Hammers and Bosman, 1986). Detection limits in the sub-ppb to ppt range may be attained with HRGC/MS techniques (EPA, 1992;Michael, et al, 1988).…”