Ecotoxicological Effects of Imidacloprid and Lambda-Cyhalothrin (Insecticide) on Tadpoles of the African Common Toad, Amietophrynus Regularis (Reuss, 1833) (Amphibia: Bufonidae)

Daniel Brice Kenko Nkontcheu, Norbert Ngameni Tchamadeu, Francis Ngealekeleoh, Stella Nchase


Agriculture is the main activity carried out in Cameroon and pesticide use is believed to be a common rule for its success. Most of the farms are situated close to water bodies, thus constituting a potential risk to non-target aquatic organisms. Declines of amphibian populations have been a worldwide issue of concern for the scientific community during the last several decades. The aim of this study was to assess the effects of an insecticide used by local farmers in Buea on amphibians. Parastar 40WP® which is constituted of imidacloprid + lambda-cyhalothrin a commonly used insecticide was applied on tadpoles of the African common toad Amietophrynus regularis (Reuss, 1833) in a static renewal experiment. The acute toxicity test was carried out after a range finding test from which seven test concentrations were selected. These concentrations were 0.0025mg/l, 0.005mg/l, 0.01mg/l, 0.05mg/l, 0.1mg/l, 0.5mg/l and 0.2mg/l. Signs of toxicity such as hyperactive symptoms, loss of balance, motionlessness and death were recorded. A varying degree of mortality (dose-dependent) was noticed during the test. On the contrary, no such toxicity signs and mortality occurred in the control, indicating that they were caused by the test substance. The 24h LC50 was 3.66mg/l, which is less than the recommended application dose (125mg/l). Products constituted of imidacloprid and lambda-cyhalothrin should therefore be handled with care and far from water bodies because of their potential to cause harm to non-target aquatic biota.


Acute; Amphibians; Insecticide; Tadpoles; Dose-dependence.


Ezemonye, L. I. N. and I. Tongo. "Lethal and sublethal effects of atrazine to amphibian larvae." Jordan Journal of Biological Sciences 2 no.1 (2009): 29-36.

Garric, J. "La contamination des eaux superficielles par les produits phytosanitaires : les effets sur le milieu aquatique". Ingénieries-EAT 10(1997):55-64.

Mann, R. M. and J. R. Bidwell. "The acute toxicity of agricultural surfactants to the tadpoles of four Australian and two exotic frogs." Environmental Pollution 114(2001): 195-205.

Mbiapo, F.D and G. Youovop: Pesticides use in Agriculture, Public health and Animal Husbandry in Cameroon. In Impact of Pesticides use on Health in developing Countries (IDRC) IDRC International Development Research Centre (1993).

Mert, G. and H. Sibel. "Morphological and histological effects of copper sulphate on the larval development of green toad, Bufo viridis." Turk. J. Zool 36 no 2 (2012): 231-240.

NPIC: Ecotoxicology. Oregon State University. (2011).

Reish, D.J. and P.S. Oshida "Manual of methods in aquatic environment research. Part 10. Short-term static bioassays." FAO Fish. Tech.Pap. 247(1986): 62 p.

Souop, D. Obsolete pesticides stocks in Cameroon. In: OECDFAO-UNEP workshop in obsolete pesticide. 13-15 September 2000; Ms Anne LINDSAY, Alexandra,Virginia. (2000).

Manfo F.P.T., P.F. Moundipa, H. Déchaud, A.N Tchana, E.A. Nantia, M.T. Zabot and M. Pugeat. "Effect of agro-pesticides use on male reproductive function: a study on farmers in Djutitsa (Cameroon)." Env. Toxicol. DOI 10.1002:1-10 (2010).

Wei, L., Shao, W., Ding, G., Fan X., Yu M. and Lin Z.”Acute and joint toxicity of three agrochemicals to Chinese tiger frog (Hoplobatrachus chinensis) tadpoles.” Zoological Research 35 no4 (2014):272-279.

FAO. "Pesticides as water pollutants". Available online at (Accessed 12-11-2010).

Kenko NDB, Patricia ABF, Ngameni TN, Mpoame M. " Environmental and Human Health Assessment in Relation to Pesticide Use by Local Farmers and the Cameroon Development Corporation (CDC), Fako Division, South-West Cameroon" . European Scientific Journal (2017) Vol.13, No.21: 454-473.

Ngameni TN, Kenko NDB, Djomo NE. " Évaluation des facteurs de risques environnementaux liés à la mauvaise utilisation des pesticides par les maraîchers au Cameroun: le cas de Balessing à l’Ouest Cameroun" Afrique Science 13(1) (2017) 91-100.

UB (University of Buea). "The town of Buea". URL:, (Accessed July 2017).

Malherbe W, Van Vuren JHJ and Wepener V. "Preliminary risk assessment of common-use pesticides using PRIMET and PERPEST pesticide risk models in a semi-arid subtropical region". Water SA (2013) 39(5):599-609

Bhavika D and Pragna P. "Behavioural responses to acute exposure of Imidacloprid and Curzate on Labeo rohita (Hamilton, 1822)". International Journal of Open Scientific Research (2014)2 (1): 1-12.

IUPAC [International Union of Pure and Applied Chemistry] "IUPAC Footprint Pesticide Properties Database (PPDB)". URL: (Accessed May 2017).

Bruhl CA, Schmidt T, Pieper S and Alscher A. "Terrestrial pesticide exposure of amphibians: An underestimated cause of global decline?" Scientific Reports (2013)3: 1135 | DOI: 10.1038/srep01135.

Méndez M, Obando P, Pinnock-Branford M, Ruepert C, Castillo LE, Mena F & Alvarado G. "Acute, chronic and biochemical effects of chlorothalonil on Agalychnis callidryas, Isthmohyla pseudopuma and Smilisca baudinii tadpoles ". Environ Sci Pollut Res (2016).23:21238–21248.

Lajmanovich RC, Attademo AM, Peltzer PM, Junges CM, Cabagna MC. "Toxicity of Four Herbicide Formulations with Glyphosate on Rhinella arenarum (Anura: Bufonidae) Tadpoles: B-esterases and GlutathioneS-transferase Inhibitors". Arch Environ Contam Toxicol (2011) 60:681–689.

Full Text: PDF

DOI: 10.28991/ijse-01112


  • There are currently no refbacks.

Copyright (c) 2017 Daniel Brice Kenko Nkontcheu, Norbert Ngameni Tchamadeu, Francis Ngealekeleoh, Stella Nchase