Effects of indirect toxicity of interacting Cd–Zn in a planktonic marine system

Abstract

Traditional toxicity bioassays usually assess the effects of single substances on isolated species, which does not, however, allow the identification of potential effects in natural systems. In addition, quantitative estimations of metal uptake in top consumers due to feeding are generally focused on the individual level and do not evaluate the consequences of metal addition at demographic or population levels. An experimental system, composed of the marine microalga Nannochloris oculata Droop, 1955 and the herbivorous rotifer Brachionus plicatilis Müller, 1786, was implemented in order to evaluate (1) whether the interaction of 2 metals, Cd and Zn, causes a greater toxic effect on planktonic species than that obtained through the addition of single metals and (2) whether the toxicity of these metals on a target herbivore population increases through the indirect route of food intake. Factorial experiments were developed, and results indicated that the toxicity on populations was higher when metals were combined, suggesting resource-dependent interaction. Consumption of contaminated algae had a negative effect on the growth rate of B. plicatilis, driven mainly by decreased juvenile and adult survival. This effect was opposite to the direct effect of dissolved metals in the medium. It is suggested that assessment of the interaction between toxic substances, as well as between populations, inserted in trophic networks, is necessary when quantifying the effects of disturbances on marine populations. Finally, our results highlight the relevance of indirect effects using a purely demographic tool focused on population level.

Diapause as escape strategy to exposure to toxicants: response of Brachionus calyciforus to arsenic

“…Although our study was focused on arsenic, at concentrations currently occurring in some natural ponds (Pell et al 2013), most likely these animals are not exposed to a single heavy metal, which may influence in the rotifer response to these toxicants (Jara and Aránguiz-Acuña 2013). Ríos-Arana et al (2005) showed contrasting effects on induction of heat shock protein HSP60 by the rotifer Plationus patulus when was exposed to arsenic alone and to arsenic mixed with other heavy metals.…”

Heavy metal pollution in Guangdong Province, China, and the strategies to manage the situation

“…Kippler et al (2012) found that early-life low-level cadmium exposure was associated with lower child intelligence scores. Interactions between Cd and other molecules and ions, such as PCB (Buha et al, 2013) or zink (Jara and Aránguiz-Acuña, 2013), may lead to enhanced Cd toxicity.…”

Monitoring of genotoxicity in marine zooplankton induced by toxic metals in Ennore estuary, Southeast coast of India

“…These results suggest that zooplankton may be exposed to metals through interaction with metal contaminated particles and/or through dietary uptake of metal contaminated food. Recently, several laboratory investigations have shown that dietary uptake is one of the major sources of metal accumulation in zooplankton (Adam et al, 2002;Barata et al, 2002;Jara and Aránguiz-Acuña, 2013). Furthermore, high chlorophyll-a was observed throughout the year, specifically during PRM and MON.…”