IDENTIFICATION OF HETEROAROMATIC AND OTHER ORGANIC-COMPOUNDS IN-GROUND WATER AT CREOSOTE-CONTAMINATED SITES IN DENMARK

The occurrence of heteroaromatic compounds (NSO) and their degradation products in ground water at creosote-contaminated sites in Denmark wa s investigated, NSO are of special interest because of their high pola rity. toxicity, and adverse organoleptic properties. In total, the con tent of about 50 organic tar compounds and the chemical redox paramete rs of ground water from three creosote-contaminated sites were determi ned. The organic contamination of ground water varied considerably bet ween sites and wells with concentrations up to mg/L level. The major o rganic contaminants were NSO, phenols, and monoaromatic hydrocarbons, which are among the most water-soluble creosote compounds. High concen trations (several mu g/L) of these compounds were observed downgradien t of the contamination source. Within a distance of 50 to 80 m from th e source. the concentrations of most compounds were reduced significan tly, often below detection limits. The NSO constituted from 0.1 percen t to 73 percent of all organic compounds determined by gas chromatogra phy (GC) with an increasing dominance downgradient of the source. Amon g the 17 studied NSO, carbazole, thiophene, benzothiophene, dibenzothi ophene, benzofuran, and dibenzofuran were observed most frequently (de tection frequency > 60 percent). High concentrations (> 100 mu g/L) of some NSO such as benzothiophene, carbazole, hydroxyquinolines, and ba sic N-compounds were observed occasionally. Other recent studies on cr eosote contamination support the present observations of high ground w ater concentrations of basic N-compounds and the high detection freque ncy of the aforementioned NSO. However, unlike the other studies, we d id observe thiophene (1-10 mu g/L).