Gammarus pulex (L.) collected from clean sites around Kabaklı pond (Diyarbakır) was acclimatized at 15°C for 10 days. This relatonship was found to be statistically significant (P | Tr. J. of Biology 23 (1999) 513–521 © TÜBİTAK Acute Lethal Toxicity and Accumulation of Copper in Gammarus pulex (L.) (Amphipoda) Kemal GÜVEN, Cengizhan ÖZBAY, Erhan ÜNLÜ, Ali SATAR Department of Biology, Science and Art Faculty, Dicle University, 21280, Diyarbakır–TURKEY Received: Abstract: Gammarus pulex (L.) collected from clean sites around Kabaklı pond (Diyarbakır) was acclimatized at 15°C for 10 days. The individuals were placed in 1lt. vessels and exposed to Cu++ concentrations of , , , , , and ppm to determine both 24, 48, 72 and 96 h LC50 values and Cu++ accumulation over 96h. LC50 values at 24, 48, 72 and 96 h were calculated to be , , and ppm, respectively. Acute copper accumulation in gammarids exposed to various copper concentrations over 96 h was determined using an atomic absorption spectrophotometer. An equation of logY=, r= was obtained from the relationship between the copper concentration of the surrounding water (X) and the body copper accumulation (Y) in G. pulex. This relatonship was found to be statistically significant (P<). There was an increase in copper accumulation rate in proportion to water copper concentrations. Key Words: Copper toxicity testing, accumulation, bioindicator, Gammarus pulex. Bakır’ın Gammarus pulex (L.) (Amphipoda)’deki Akut Letal Toksisitesi ve Birikimi Özet: Kabaklı Göleti (Diyarbakır) civarındaki kirletilmemiş küçük bir su kaynağından alınarak laboratuara getirilen Gammarus pulex (L.) örnekleri, 15°C sıcaklıkta 10 günlük bir adaptasyon süresine tutulmuştur. Adaptasyon gösteren bireyler, (kontrol), , , , , , ve ppm Cu++ konsantrasyonlarında su bulunan kaplar içine alınarak 24, 48, 72 ve 96 saatlik sürelerdeki LC50 değerleri hesaplanmıştır. LC50 değerleri 24 saat için ppm; 48 saat için ise ppm; 72 saat için ppm ve 96 saat için ppm olarak bulunmuştur. Akut letal konsantrasyonlarda .