Chemical analyses of water, sediment and biota in two small streams in southwest Germany

Abstract

As a component of the VALIMAR project a comprehensive chemicalanalysis study was conducted in two small streams, the Körsch andthe Krähenbach, in southern Germany. The investigated pollutantswere heavy metals (HM), polycyclic aromatic hydrocarbons (PAHs),polychlorinated biphenyl's (PCBs) and a set of 33 pesticides.Samples from stream water, sewage treatment plant effluents,stream sediment and fish were analyzed. In the stream water, HMand PAHs showed slightly higher concentrations in the Körsch thanin the Krähenbach, whereas the pesticide concentrations (mainlyplant protective agents) were significantly higher in the Körschthan in the Krähenbach. Because of their similar occurrence andconcentrations in the Körsch water and in the sewage treatmentplant effluent, it appears that most of the pesticides wereintroduced into the river via the sewage treatment plant. Only inthe cases of terbuthylazine, triallate, chlorfenvinfos,metazachlor and mecoprop were the occurrence and concentrationsin the Körsch higher suggesting that run-off was the mostimportant route for these five compounds in this stream.

The sediments of the two streams clearly differed in terms ofpollutant concentration. Polycyclic aromatic hydrocarbons, PCBsand HM were found in slightly higher concentrations in the Körschthan in the Krähenbach whereas pesticide concentrations weresignificantly higher in the Körsch. Results of each samplingdemonstrated extreme variations, due to frequent high-watersituations that led to high turnover and wash out of thesediment. In the sediment samples, most of the detected compoundswere more lipophilic than were those detected in water.

Brown trout (Salmo trutta f. fario) and loach (Barbatulabarbatula) were sampled directly from the natural streams, from astream water fed bypass exposure system, and from a controlsystem in the laboratory. In the case of PAHs, PCBs andpesticides, concentrations were higher in fish exposed to theKörsch water than to the Krähenbach water. Heavy metals did notdifferentiate between the two streams. Polychlorinated biphenylsand pesticides showed higher concentrations in fish from thefield, which can be explained by longer exposure periods. Incontrast, PAHs showed the lowest concentrations under fieldconditions. Polycyclic aromatic hydrocarbons were possiblydisplaced by other compounds of high concentration. The pesticidepatterns in trout were quite similar in the different exposuretypes with primarily lindane, PCP and trifluraline contributingto these pattern changes. In loach, larger variations in allcontaminant concentrations were found but the same threecompounds also contributed most to the observed pattern changes.

The analytical results were compared with various internationalobjective values for a good water quality as well as with valuesfrom other studies concerning the pollutant concentrations ofsediment and fish. All collected chemical data form a basis forthe biomarker investigations conducted by the other participantsof the VALIMAR project in order to find correlations betweenbiomarker responses and chemical pollution data of the twostreams.