Mentum Deformities of Chironomid Larvae as an Indicator of Environmental Stress in Büyük Menderes River, Turkey

River basins are important for both industrial and agricultural activities. Pollution of air, water and soil is increasing owing to an insufficient number of treatment facilities; thus, most industrial and domestic wastewater either is directly discharged into water or is improperly treated. Here Chironomus spp. mentum deformities were used to determine environmental stress sources. A total of 4701 chironomid larvae were collected from 31 stations located in the Buyuk Menderes River Basin. The mean mentum deformity incidence was 2.82%, and the frequency of deformities varied from 0 to 14.7%, with the highest frequencies calculated for the Dokuzsele (14.7%) and Banaz (9%) streams. The feature common among both stations is that they receive wastewater from textile, tannery and agricultural facilities. Our results show that mentum deformities are at least five times more pronounced at the most highly polluted sampling stations and indicate that mentum deformities of chironomid larvae are strongly related to ammonium-N and Cl is positively associated with agricultural and household wastewater.