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    ABSTRACT: If an organism does not feed, it dies of starvation. Even though some insecticides which are used to control pests in agriculture can interfere with feeding behavior of insects and other invertebrates, the link from chemical exposure via affected feeding activity to impaired life history traits, such as survival, has not received much attention in ecotoxicology. One of these insecticides is the neonicotinoid imidacloprid, a neurotoxic substance acting specifically on the insect nervous system. We show that imidacloprid has the potential to indirectly cause lethality in aquatic invertebrate populations at low, sublethal concentrations by impairing movements and thus feeding. We investigated feeding activity, lipid content, immobility, and survival of the aquatic arthropod Gammarus pulex under exposure to imidacloprid. We performed experiments with 14 and 21 days duration, both including two treatments with two high, one day pulses of imidacloprid and one treatment with a low, constant concentration. Feeding of G. pulex as well as lipid content were significantly reduced under exposure to the low, constant imidacloprid concentration (15 µg/L). Organisms were not able to move and feed - and this caused high mortality after 14 days of constant exposure. In contrast, feeding and lipid content were not affected by repeated imidacloprid pulses. In these treatments, animals were mostly immobilized during the chemical pulses but did recover relatively fast after transfer to clean water. We also performed a starvation experiment without exposure to imidacloprid which showed that starvation alone does not explain the mortality in the constant imidacloprid exposure. Using a multiple stressor toxicokinetic-toxicodynamic modeling approach, we showed that both starvation and other toxic effects of imidacloprid play a role for determining mortality in constant exposure to the insecticide.
    Full-text · Article · May 2013 · PLoS ONE
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    ABSTRACT: Arsenic is a naturally occurring element with a long history of toxicity. Sites of contamination are found worldwide as a result of both natural processes and anthropogenic activities. The broad scope of arsenic toxicity to humans and its unique interaction with the environment have led to extensive research into its physicochemical properties and toxic behavior in biological systems. The purpose of this review is to compile the results of recent studies concerning the metalloid and consider the chemical and physical properties of arsenic in the broad context of human toxicity and phytoremediation. Areas of focus are arsenic's mechanisms of human toxicity, interaction with plant systems, potential methods of remediation, and protocols for the determination of metals in experimentation. The assessment of the literature concludes that controlling contamination of water sources and plants through effective remediation and management will be essential to properly address the problems of arsenic toxicity and contamination.
    No preview · Article · Aug 2015 · Journal of Agricultural and Food Chemistry