Semi-volatile organic compounds in the Campaspe River system (Victoria, Australia)

The levels of semi-volatile organic compounds (SVOCs) in the Campaspe River system, North Central Victoria, Australia, were monitored from January to September 1995, and the environmental trends and sources of these compounds were determined. The land use within particular catchments dictated the co mplexity of the SVOCs in run-off water. Run-oh from native forest contained the greatest number of SVOCs. Soil and ground litter were shown to contain the greatest complexity of SVOCs. mostly terpenes. However, only a small p roportion were leached by run-off with the remainder being rightly bound to the soil or volatilizing to the atmosphere. Under the prevailing drought o f early 1995, the rivers contained no detectable SVOCs until the first catc hment run-off after significant rainfall in May. The maximum complexity and concentration of the SVOCs coincided with extensive run-off after heavy ra infall in June. effecting a surge of SVOCs with the flood peak. Fatty acids . their amides and hydrocarbons made up the majority of the compounds ident ified and were in the 1-39 mug/l concentration range. The levels then dimin ished as the catchment was flushed by continual run-off. These results supp ort Lake's 1967 hypothesis that natural floodwaters contain a signature of SVOCs entering from the catchment. The downstream passage of these compound s was obstructed by a man-made storage, Lake Eppalock, with only low concen trations of SVOCs (1-3 mug/l) in the outflow, displaying no correlation to run-off. (C) 2001 Elsevier Science Ltd. All rights reserved.