TOXIC EFFECTS of WATER-SOLUBLE FRACTIONS (WSF) of BASRAH REGULAR CRUDE OIL to LARVAE of FRESH WATER SHRIMP (CARIDINIA BABAULTI BASRENSIS AL–ADHUB and HAMZA) and RIVER CRAB (SEASARMA BOULENGERI CALMAN) from SHATT AL-ARAB RIVER, IRAQ

A. Farid, Wisam

	TOXIC EFFECTS of WATER-SOLUBLE FRACTIONS (WSF) of BASRAH REGULAR CRUDE OIL to LARVAE of FRESH WATER SHRIMP (CARIDINIA BABAULTI BASRENSIS AL–ADHUB and HAMZA) and RIVER CRAB (SEASARMA BOULENGERI CALMAN) from SHATT AL-ARAB RIVER, IRAQ
AL-TAQANI
Article 1, Volume 24, Issue 7, 2011, Pages 52-62
Author
Wisam A. Farid
Abstract
In the present study, the toxicity experiments were conducted with intermolt and molting larvae (stage I) of freshwater shrimp C. babaulti basrensis and river crab S. boulengeri from Shatt Al–Arab river. The larvae of the two species were exposed to different concentrations (0.8, 1.6, 2.4, 3.2, 4.8 and 6.4ppm) of WSF of Basrah regular crude oil in the static toxicity system for 96 hours period. In the terms of median lethal concentrations (LC50), The molting larvae of shrimp and crab were more sensitive than intermolt one to WSF of crude oil. The intermolt and molting larvae of shrimp were more sensitive than were intermolt and molting larvae of crab. Further toxicity experiments were conducted with the molting larvae of shrimp and crab. The larvae were exposed to different concentrations of WSF of crude oil, (0.3, 0.5, 1.0 and 1.9ppm) for shrimp and (0.6, 0.9, 1.8 and 2.8ppm) for crab, to different exposure periods (12, 24, 48, 72 and 96 hours) in the renewal toxicity system. After exposure periods were over, the larvae were transferred to clean river water for recovery and further observations. The total time for each test (exposure period+the period in clean river water) was 168 hours. The high concentrations of WSF of crude oil [1.9ppm (shrimp) and 2.8ppm (crab)] reduced molting success of shrimp and crab larvae by 80 and 91% respectively after 24 hours period of exposure and some deaths occurred. While these high concentrations declined the molting success of shrimp and crab larvae by 95 and 98% respectively after 96 hours period of exposure, and larvae usually died. The lowest concentrations of WSF of crude oil [0.3ppm (shrimp) and 0.6ppm (crab)] did not inhibit molting of shrimp and crab larvae at any period of exposure, but many larvae died after molting. The 168 hours LC50 values for molting larvae of shrimp and crab were lower than the 96 hours LC50 values of molting larvae of the both species.

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