Journal of Environmental Biology

Effects of DDT and dicofol on population growth of Brachionus calyciflorus under different algal (Scenedesmus obliquus) densities

Xiao-Ping Xu^1,2, Yi-Long Xi¹*, Zhao-Xia Chu³ and Xian-Ling Xiang¹

¹Key Laboratory of Biotic Environment and Ecological Safety in Anhui Province, College of Life Sciences,

Anhui Normal University, Wuhu, Anhui, 241000, China

²School of Management Engineering, Anhui Polytechnic University, Wuhu, Anhui, 241000, China

³Department of Life Science, Huainan Normal University, Huainan, Anhui, 232001, China

*Corresponding Author?s Email : ylxi1965@126.com 

Publication Data

Paper received:

01 March 2013

Revised received:

06 July 2013

Accepted:

16 August 2013

Abstract

A number of organochlorine pesticides, including DDT and dicofol, used to be important in crop protection and management. Their residues may reach water bodies and eventually affect the non-target organisms such as rotifers. In the present study, we evaluated the effects of DDT (0.05, 0.1, 0.2 and 0.4 mg l^-1) and dicofol (0.1, 0.2, 0.4 and 0.8 mg l^-1) on the population growth of rotifer Brachionus calyciflorus under two levels of Scenedesmus obliquus (1.0?106 and 3.0?106 cell ml^-1). Regardless of the food level, DDT was more toxic than dicofol to B. calyciflorus. Under low food level, DDT at 0.1 and 0.2 mg l^-1 decreased the population growth rate (r), and DDT at 0.05-0.4 mg l^-1 decreased the maximum population density (K). Dicofol at 0.4 and 0.8 mg l^-1 decreased r and K, but dicofol at 0.2 mg l^-1 increased K. Under high food level, DDT at 0.05-0.2 mg l^-1 increased K, whereas DDT at 0.4 mg l^-1 as well as dicofol at 0.4 and 0.8 mg l^-1 decreased r and K. Increase in food level increased r exposed to DDT at 0.05-0.2 mg l^-1 as well as dicofol at 0.8 mg l^-1, and K exposed to DDT at 0.05-0.2 mg l^-1 as well as dicofol at 0.1 and 0.2 mg l^-1. DDT concentration, algal density and their interaction affected r and K of B. calyciflorus. Both dicofol concentration and algal density affected r. Dicofol concentration, algal density and their interaction affected K. Both r and K were suitable endpoints for assessing the effects of DDT and dicofol on the rotifers population dynamics under two algal densities, and the latter was more sensitive. 

Key words

Algal density, Brachionus calyciflorus, DDT, Dicofol, Population growth rate

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