TITLE:
Active in Situ Biomonitoring of Pesticide Pulses Using Gammarus spp. in Small Tributaries of Lake Constance
AUTHORS:
Almut Gerhardt, Margie Koster, Frank Lang, Vera Leib
KEYWORDS:
Active Biomonitoring; Gammarus; Field Test; Ecotoxicology
JOURNAL NAME:
Journal of Environmental Protection,
Vol.3 No.7,
July
18,
2012
ABSTRACT: Gammarids are important members of a stream’s macrozoobenthos biocoenosis and food web. Moreover, they proved to be very sensitive towards different types of pollution. GamToxTM is a new in situ ecotoxicity test, based on survival and feeding behavior of caged gammarids for active monitoring of small streams in agricultural areas. GamToxTM has been applied in two streams with specific pollution problems in the catchment of Lake Constance. Ten organisms were exposed in 5 replicates in flow through test tubes containing one conditioned alder leaf, placed in baskets which were attached in the stream bottom and on the banks. Each week, the number of living animals was counted, the percentage of leaf skeletized estimated in semi-quantitative classes and a new elder leaf provided. Dead organisms were removed. Simultaneously, chemical analyses of pesticides and nutrients (N-compounds, P) were performed on cumulative water samples over one week. Moreover, macrozoobenthos was collected and determined according to the IBCH method, and the SPEAR index calculated. GamToxTM proved to be very sensitive to detect pesticides, copper as well as nutrients, both during acute pollution pulses and chronic exposures of up to 6 weeks. Survival turned out to be a more sensitive and less variable parameter than feeding. GamToxTM is easy to perform and directly provides a measure of ecotoxicological effects of toxicant/nutrient mixtures, which cannot be predicted by biological indices based on macrozoobenthos data such as IBCH and SPEAR-index. This study was co-financed by the InterReg IV project “?kotoxikologischer Index im Bodenseeraum”, no. 227 (2011-2013) supported by the EFRE.