ABSTRACT
Periwinkles (Tympanotonus fuscatus) handpicked from the New Calabar River were acclimated to laboratory conditions in the research laboratory of the Chemistry Department of the Ignatius Ajuru University of Education, Rumuolumeni, Port Harcourt. They were subjected to concentrations (60, 90, 120, 150 and 200 ml/L) of a petroleum product, kerosene and a control to examine the effect of acute exposure on mortality of the periwinkles. The mean mortality of the periwinkles increasing with the concentration of the kerosene and the exposure time. The mean lethal concentration (96 hr LC50) of the kerosene was 111.14 ml/L, while the 96 hr LC99 was 433.94 ml/L and the probit equation at that hour, Y= -0.80 + 0.007X was significant. The mean lethal time (MLT50) at 60, 90, 120, 150 and 200 ml/L with the associated confidence limits were 90.13 (52.94–126.45), 84.06 (61.40–110.50), 79.02 (42.00–105.06), 73.27 (40.74–96.30) and 70.17 (39.84–94.20) ml/L respectively. The data obtained from the laboratory is an indication that kerosene is toxic to periwinkles which can be extrapolated to field conditions in the event of a spill.