ABSTRACT

The weight and the length of the test organism was taken and recorded. The weight of test organism (Tilapia guineensis) was 222.5 ± 2.11 mg while the length was 1.5 ± 0.03 cm. The physicochemical analysis of habitat water was carried out in order to establish if the habitat water can support life. All test organisms were first acclimatized for ten (10) days at room temperature (28 ± 2º̊C). Range finding test was carried out to establish a preliminary working range by obtaining the least concentration that gives no effect and the minimum concentration that gives 100 % death. Acute toxicity tests were carried out with the aquatic organism (Tilapia guineensis) by exposing them to test solutions (SDS and GC) containing various concentrations of the test solutions using the semi – static agitation test procedure as recommended by Department of Petroleum Resources (DPR). The number of test organism decreased with respect to time even at a particular concentration and also decreased as concentration increased. From the result, it was also observed that as % survival decreased with respect to time even at a particular concentration, % mortality increased with respect to time and also % survival decreased while % mortality increased as concentration increased. This could be attributed to the effect of GC and SDS on the test organism since the control did not follow this trend. This showed that the longer the time of exposure, the more the effect of GC and SDS on Tilapia guineensis. A comparative assessment of the two dispersants SDS and GC showed that GC was more toxic to the test organism Tilapia guineensis than SDS at the same concentration. This is because a slight concentration of 0.05 ml/L of GC gave 90 % mortality after 48 h exposure while 100 mg/L SDS gave 100 % mortality at the same duration. Also at 0.05 ml/L GC and 100 mg/L SDS  for exposure period of 72 and 96 h, GC and SDS gave same 100 % mortality. Hence gold crew should be treated as more toxic dispersant compared to SDS at various concentrations and exposure time.