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Dissolved Organic Matter or Salts Change the Bioavailability Processes and Toxicity of the Nanoscale Tetravalent Lead Corrosion Product PbO2 to Medaka Fish

Chiang, Chun-Wei, Ng, Ding-Quan, Lin, Yi-Pin, Chen, Pei-Jen
Environmental science 2016 v.50 no.20 pp. 11292-11301
Oryzias latipes, aquatic environment, bioavailability, chlorination, corrosion, dissolved organic matter, drinking water, fish, ionic strength, larvae, lead, nanoparticles, neurotoxicity, oxidative stress, pollution, risk, salinity, salts, stress response, surface water
Nanoscale lead dioxide (nPbO₂₍ₛ₎) is a corrosion product formed from the chlorination of lead-containing plumbing materials. This metal oxide nanoparticle (NP) plays a key role in determining lead pollution in drinking water and receiving water bodies. This study uses nPbO₂₍ₛ₎ and medaka fish (Oryzias latipes) as surrogates to investigate the aqueous fate and toxicological risk of metal oxide NPs associated with water matrices. The larvae of medaka were treated with solutions containing nPbO₂₍ₛ₎ or Pb(II)ₐq in different water matrices for 7–14 days to investigate the in vivo toxic effects of NPs. Ionic strength enhanced aggregation and sedimentation of nPbO₂₍ₛ₎ in water, leading to increased lead contents in fish bodies. However, the presence of dissolved organic matter in water enhanced particle stability and accelerated the lead dissolution, thus changing the bioavailability processes (bioaccessibility) of particles. Oxidative stress response and neurotoxicity in exposed fish was greater for nPbO₂₍ₛ₎ solution with increased salinity than dissolved organic matter. We predict the bioavailability processes and toxicity of nPbO₂₍ₛ₎ in medaka from the aqueous particle behavior under environmentally relevant exposure conditions. Our investigation suggests a toxicological risk of metal oxide NP pollution in the aquatic environment.