Eco-toxicology effect on Moina mongolica Daday exposed to Cd 2+ , Pb 2+ , and Hg 2+ by the food chain

Abstract

As one of the most important contaminants, heavy metals can seriously influence human health via the food chain. In this study, the eco-toxicological effects of Cd²⁺, Pb²⁺, and Hg²⁺ on Moina mongolica Daday were investigated by feeding them Chlorella sp. that contained heavy metals. The relative body lengths of the M. mongolica changed rapidly, peaking at 2 days for Hg²⁺, 6 days for Cd²⁺, and 8 days for Pb²⁺. Moreover, grazing and clearance rates of the experimental group were apparently lower than those of the control group after immersion in heavy metals. Additionally, Cd²⁺ and Pd²⁺ in the food significantly influenced the mean lifespan of M. mongolica of the P and F₁ generations. Egg production per brood was also significantly impacted by Cd²⁺ and Pb²⁺ in the food in generation P. Interestingly, Pb²⁺ was the only metal that significantly influenced the reproduction times of F₂, while the reproductive times were significantly influenced by Cd²⁺ for generation P. Moreover, Cd²⁺, Pb²⁺, and Hg²⁺ in the food significantly influenced the fecundity of generation P. Evaluation of the population growth parameters of M. mongolica revealed that the intrinsic rate of increase, net reproduction rate, and finite rate of increase were significantly influenced by Cd²⁺, Pb²⁺, and Hg²⁺ in the food in generation P. Additionally, Hg²⁺ slightly impacted generation time for generation P. Finally, the acute toxicity toward M. mongolica was Hg²⁺ > Cd²⁺ > Pb²⁺. Overall, heavy metals in the food were likely to influence the growth, survival, and population growth of M. mongolica through the food chain.