Flavour Compounds in Weakly Polluted Rivers as a Means to Differentiate Pollution Sources

Abstract

The volatile organic compounds of eight weakly polluted small rivers and brooks in SW Germany were studied by GC-MS. Special emphasis was placed on the differentiation between biogenic and anthropogenic sources and the use of particular compounds or patterns of compounds to characterize the pollution sources. Mono- and sesquiterpenes, which were liberated by wood processing industries, could clearly be distinguished from those which came from odorants of household detergents. In nearly every water sample geosmin was present while 2-MIB was not found in a single case. Nor-carotenoids were frequently observed in all river waters. The seasonal occurrence (summer) of 3-butenylisothiocyanate in several river waters was unexpected. Experiments with rape plants and soil from rape fields showed that this compound is leached from rape. However, the source of methylisothiocyanate that notoriously occurred in one river could not be established (acarizide or biogenic). Different patterns of esters were used to differentiate between the discharge of a paint manufacturer and a sewage treatment plant. Linear and cyclic hydrocarbons could be divided into a biogenic and anthropogenic fraction. Alkyl benzenes were found only in those rivers which were affected by industrial activities.