Acute Toxicity Of Npk (15:15:15) Fertilizer To Tilapia zilli Fingerlings

Abstract

Acute toxicity of the inorganic fertilizer NPK (15:15:15:) to the fingerlings of Tilapia zilli (mean weight 8.05 ± 0.42g) was investigated using static bioassays over a period of 96 hours. The 96hr LC50 of the exposed fish was determined to be 1.05g/L with lower and upper confidence limits being 0.32 and 3.49g/L respectively. Restlessness, loss of balance and erratic swimming due to stress were commonly observed before death. Water quality examination showed decrease in dissolved oxygen content and increase in both alkalinity and conductivity as the concentration of the fertilizer was increased. Consequences of strategic fertilizer applications are discussed.

Keywords: ke NPK (15-15-15) fertilizer, Acute toxicity, Tilapia zilli fingerlings.

Nigerian Journal of Fisheries Vol. 5 (1) 2008: pp. 31-37