Effects of dietborne cadmium on life history and secondary production of a tropical freshwater cladoceran

Abstract

The presence of metals in aquatic environments has increased worldwide. Environmental assessments of metals in freshwater ecosystems presume that toxicity is mainly caused by aqueous exposure, but dietborne exposure (contaminated food) in zooplankton may occur because microalgae carry metal ions through adsorption/absorption of dissolved metal species, resulting in toxic effects once ingested by the animals. However, official regulations for ecotoxicological assays in most countries do not consider the toxic effects caused by dietborne exposure. Here, we provide life history parameters and secondary production of Simocephalus serrulatus (Koch 1841) (Cladocera: Daphniidae) fed with cadmium (Cd) contaminated algae during a 21-day bioassay. The microalgae Chlorophyceae Scenedesmus quadricauda was exposed for 96 h to dissolved Cd concentrations of 0.03; 5.87; 12.27 and 22.27 µg Cd l(-1) (equivalent to 1.6 × 10(-10); 3.2 × 10(-8); 6.7 × 10(-8); 1.2 × 10(-7) mol l(-1)) that resulted in algae internal Cd burdens of 0.004; 0.032; 0.270 and 0.280 pg Cd cell(-1), respectively. Significant toxic effects on life history parameters of S. serrulatus were observed. Time of embryonic development, generation time and age at first reproduction (primipara) showed significant delay. Length at first reproduction, number of eggs and clutches produced per female, hatching percentage, body length, survival and feeding rates were significantly reduced. Secondary production, that is, accumulated biomass for growth and reproduction, decreased significantly with dietborne Cd concentrations. Our results emphasize that food can be an important source of metals to zooplankton in aquatic ecosystems. Environmental regulations should consider the diet in ecotoxicological assessments. Furthermore, secondary production may be considered as a suitable endpoint in ecotoxicity tests.

Ecotoxicological assessment of estuarine surface waters receiving treated and untreated sanitary wastewater

“…The fuels and lubricating oils used in this port have high concentrations of metals, namely Cd, Cr, Cu, Mn, Ni, Pb, and Zn (Pulles et al, 2012;Coufalík et al, 2019). Studies on the presence of these metals in domestic wastewater (Souza et al, 2014;Thewes et al, 2011) support the role of wastewater emissions in metal pollution in the aquatic environment.…”

“…The increasing accumulation of exogenous substances in estuarine areas has negatively affected their biota and led to ecosystem imbalance (Pimentel et al, 2016). In addition, toxic compounds can bioaccumulate and be transferred through the food chain (Souza et al, 2014), posing a risk to human health (Rabaoui et al, 2017).…”

Fronteiras da engenharia e ciências ambientais: perspectivas multidisciplinares

“…No Brasil, podem-se elencar alguns fatores críticos associados à disposição inadequada dos REEE, os quais favorecem a exposição da população aos agentes tóxicos dos REEE: (Ipea, 2013). Há evidências de que catadores e atores intermediários (sucateiros) coletam REEE no Brasil (Ongondo; Williams; Cherrett, 2011), e que alguns praticam a dissolução de Placas de Circuito Impresso (PCI) com ácido, bem como a queima de cabos e componentes, para a separação de metais (Lundgren, 2012;Souza, 2014).…”

“…Uma grande parte dos REEE no Brasil segue uma cadeia composta por atores informais, que atuam nos processos de coleta e comercialização de aparelhos e de suas partes, e que muitas vezes estão submetidos a atividades insalubres para obtenção de materiais valiosos, de forma rudimentar. Dentre os processos mais comuns identificados nas cadeias informais estão a queima de componentes para a separação de metais, e a dissolução de PCI com ácido para a obtenção de metais raros, presentes nas suas superfícies (Lundgren, 2012;Souza, 2014). Esses processos expõem os trabalhadores informais e comunidades próximas a fumaças e líquidos extremamente tóxicos, que podem causar desde problemas respiratórios a câncer e doenças neurológicas e cardíacas (Lundgren, 2012).…”

Chromium toxicity to planktonic organisms: comparison between different routes of exposure to the metal

“…While research on the accumulation and effects of metals in shell sh has traditionally focused primarily on the exposure pathway in dissolved form, researches have shown that the dietary exposure pathway can be critical and sometimes dominant (Tang et al 2011;Wang 2013). Studies that address this aspect of toxicity have been increasingly reported in the literature for copper (Rodgher et al 2009;Gusso-Choueri et al 2012;Rocha et al 2016), cadmium (Barata et al 2002;Rodgher and Espíndola 2008a;Souza et al 2014), zinc (De Schamphelaere et al 2004;Rodgher et al 2020). They are essential for understanding the trophic transfer of these elements in ecosystems.…”