Netherlands Journal of Zoology vol:47 issue:2 pages:227-239
The morphological response of Chironomus gr. thummi larvae after a spill of xylene (10 000 l) and toluene (7500 l) in a brook was investigated. At the site of the spill, the proportion of larvae with mentum and antennal deformities increased in the following months. Downstream (500 m), no such clear response could be discerned. Mandible deformities occurred as well, but the fluctuations could not be related to the pulse pollution. Fugacity and concentration models predict a higher affinity of xylene to sediments and biota. Therefore, a short term 72 h exposure test with xylene (0, 10, 100, 1000 mu l/l) was performed on early instar larvae. Fourth instar larvae with a split medial mentum tooth represented 15% of the surviving population (mortality was 44%) at a concentration of 10 mu l/l xylene.