engleski

Determination of terbuthylazine in urine of rats exposed to low doses

Pesticides are a major group of chemicals produced to be intentionally released in the environment. Many pesticides are not easily degradable ; they persist in soil, leach to groundwater and surface water and contaminate the wider environment. Depending on their chemical properties they can enter organisms, bioaccumulate in food chains and consequently influence human health. There is much data available concerning acute exposure of people or laboratory animals to pesticides. However, long-term exposure to low concentrations corresponding to real-life scenarios is much less investigated. Exposure to triazine herbicides such as terbuthylazine mainly results in urinary excretion of the parent compound and its metabolites formed by dealkylation. The aim of this study was to determine mass concentrations of terbuthylazine and its metabolites in rat urine. Animals were exposed to three different concentrations of terbuthylazineon each of 28 consecutive days. Terbuthylazine and its metabolites were determined in a 24-hour urine sample collected on the 1st, 14th and 28th day of treatment, with the results serving to define the markers and biomarkers of exposure. Different extraction procedures were developed for determining the accumulation of triazine herbicide terbuthylazine and dealkylated metabolites in rat urine: extraction with ethyl- acetate and solid- phase extraction on styrene- divinylbenzene sorbent. These procedures were optimised for final analysis by high performance liquid chromatography. Mass concentration of terbuthylazine recovered from urine indicates that unchanged terbuthylazine represents only a minor part of the adsorbed dose while the majority of terbuthylazine was excreted as dealkylated metabolites. This work has been supported in full by the Croatian Science Foundation under project no. 8366.

biomarkers of exposure ; high performance liquid chromatography ; solid phase extraction ; solvent

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