Volume 35, Issue 1, Winter 2009, Page 1-12
Short-term toxicity of regular Basrah crude oil on the fresh water snail Lymnaea auricularia (Linne' 1758) from Shatt Al-Arab River . Iraq
Journal of Basrah Researches (Sciences),
Volume 35, Issue 1, Pages 1-8
Laboratory study was conducted to evaluate the toxicity of regular Basrah crude oil on snail L. auricularia collected from Shatt Al-Arab river banks. The snails were monitored every 3 hrs. in which mortality of snails were registered numerically. Other effects of crude oil have been observed on the snails and the median lethal time (LT50) has been recorded for each concentrations. The median lethal concentration (LC50) has also been recorded for the snails within (42 hrs.) of exposure to crude oil concentrations within (0.005 , 0.010 , 0.020 , 0.030 , 0.050 , 0.070 , 0.100 , 0.150 and 0.200) mg/l. The toxicity curves were drown for each of these snails. Mortality (10 %) was appeared within 12 hours of exposure to highest concentration (0.2) mg/l while it was appeared within 33 hrs. of exposure to the lowest concentration (0.005) mg/l. The mortalities were recorded gradually for the rest concentrations in different time of exposure. No mortality appeared within 42 hrs. for control sample. Maximum LT50's calculated for snails were 45.5 hrs. and Maximum LC50's calculated for snails were 0.0912 mg/l of exposure time. As a result from the present study, the toxicity of crude oil that was studied depending upon the concentration of crude oil and the period of exposure time. The snails avoid the crude oil in the early hours of exposure by hiding inside their shells.