Impact of different crystalline forms of nTiO 2 on metabolism and arsenic toxicity in Limnoperna fortunei

Arsenic (As) is a ubiquitous contaminant in the environment and it is known to induce oxidative stress in aquatic organisms. In an attempt to remove As from water, some studies have suggested the titanium dioxide nanomaterial (nTiO(2)) as a promising alternative. However, it has been observed that nTiO(2) can induce toxicity alone or in combination with metals, and this toxicity is dependent on its crystalline form of nanomaterial (mainly rutile as nTiO(2)R and anatase as nTiO(2)A, respectively). Considering that both (nTiO(2) and As) can occur together, the objective of this study was to evaluate if co-exposure to rutile and anatase may influence accumulation, metabolisation, and toxicity of arsenite (As+3) in the golden mussel Limnoperna fortunei after 48 h of co-exposure to nTiO(2) (1 mg/L) and As (50 mu g/L). Accumulation and chemical speciation of As in organisms were determined. Also, biochemical analyses, such as the activity of the enzymes glutathione S-transferase omega (GST Omega), catalase (CAT) and glutathione S-transferase (GST), as well as lipid peroxidation (LPO) were investigated. Results showed that co-exposure to nTiO(2)A + As changed accumulation pattern of metalloid in gills and digestive gland. Both crystalline forms of nTiO(2) affected the metabolisation capacity favoring the accumulation of more toxic As compounds and nTiO(2)A alone or in combination with As showed induce oxidative stress in gills of L. fortunei. In this way, it has a high potential risk of the co-exposure of these contaminants to aquatic organisms, and it also needs to consider the nanomaterial (nTiO(2)) properties and their application in the environmental remediation, carefully and judiciously.