纳米二氧化钛对海洋硅藻有机磷酸酯累积、转化及毒性的影响OA北大核心

Metal-based nanoparticles(MNPs)are extensively employed in modern industry and everyday life,rais-ing substantial concerns about their potential risks to ecosystems.However,research on how MNPs influence the biotransformation of coexisting pollutants remains limited.This study explores the effects of nano-titanium dioxide(nTiO₂)on the accumulation,transformation,and toxicity of organophosphate esters(OPEs)in the marine diatom Phaeodactylum tricornutum.Through acute toxicity assays,single-exposure experiments,and co-exposure experi-ments with nTiO₂,it was observed that triphenyl phosphate(TPHP)exhibited significantly greater toxicity than other tested OPEs.In contrast,its primary metabolite,diphenyl phosphate(DPHP),showed markedly reduced tox-icity,indicating a detoxification effect resulting from OPE biotransformation.However,the presence of nTiO₂ sig-nificantly increased the intracellular accumulation of TPHP while reducing DPHP levels,suggesting that nTiO₂ in-hibits the conversion of TPHP to DPHP.This inhibition leads to greater TPHP retention and elevated toxicity in algae.The increased toxicity was reflected in elevated oxidative stress,as evidenced by a significant rise in super-oxide dismutase(SOD)activity and malondialdehyde(MDA)content.Further mechanistic investigations revealed that nTiO₂ enhances the adsorption and enrichment of OPEs on the algal surface while inhibiting CYP450 gene ex-pression,thereby impairing OPE metabolism and intensifying their toxic effects.This study elucidates the inhibito-ry role of nTiO₂ in the biotransformation of OPEs and its contribution to heightened toxicity.It offers new theoreti-cal insights into the interactions between nanoparticles and organic pollutants in marine environments and provides critical data for environmental risk assessment.