Acute toxicity of the chloroacetanilide herbicide butachlor and its effects on the behavior of the freshwater fish Tilapia zillii

  • Christopher Didigwu Nwani
  • Udu Ibiam Ama
  • Florence Okoh
  • Uche Obasi Oji
  • Rebecca Chima Ogbonyealu
  • Arua Agha Ibiam
  • Onyinyechi Udu-Ibiam

Abstract

Acute toxicity of butachlor, a chloroacetanilide herbicide (2-chloro-N-[2, 6-diethylphenyl] acetamide) to Tilapia zillii, was studied in a semi static bioassay. The 24, 48, 72 and 96 h LC50 values (with 95% confidence limits) estimated by probit analysis were 3.13 (2.88 to 4.61), 1.93 (0.63 to 4.41), 1.27 (0.59 to 1.92) and 1.25 (0.60 to1.85) mgl-1, respectively. There were significant differences (p<0.05) in the LC50 values obtained at different exposure times and the safe levels estimated by different methods varied from 1.25×10-1 to 1.25×10-5 mgl-1. There were dose and time dependent increase in mortality rate due to exposure to the herbicide. Stress signs in form of hyperactivity, erratic swimming, skin discoloration, vigorous jerks of the body followed by exhaustion and death were observed. The 96 h LC50 of 1.25 mgl-1 obtained indicate that the herbicide was toxic to T. zillii. Agricultural use of butachlor in the environment, especially, near water bodies, must be restricted to avoid the severe risk associated with the use of the pesticide.

Keywords: Tilapia zillii, butachlor, toxicity, mortality, behavioral changes, safe level

African Journal of Biotechnology Vol. 12(5), pp. 499-503

Author Biographies

Christopher Didigwu Nwani
Department of Zoology and Environmental Biology, University of Nigeria, Nsukka, Nigeria
Udu Ibiam Ama
Department of Biochemistry, Ebonyi State University PMB 053 Abakaliki, Nigeria
Florence Okoh
Department of Applied Biology, Ebonyi State University, PMB 053, Abakaliki, Nigeria
Uche Obasi Oji
Department of Biochemistry, Ebonyi State University PMB 053 Abakaliki, Nigeria
Rebecca Chima Ogbonyealu
Department of Biochemistry, Ebonyi State University PMB 053 Abakaliki, Nigeria
Arua Agha Ibiam
Department of Industrial Mathematics, Ebonyi State University, PMB 053, Abakaliki, Nigeria
Onyinyechi Udu-Ibiam
Department of Biochemistry, Ebonyi State University PMB 053 Abakaliki, Nigeria
Published
2015-11-29
Section
Articles

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eISSN: 1684-5315