Interaction Effects On Uptake And Toxicity Of Perfluoroalkyl Substances And Cadmium In Wheat (Triticum Aestivum L.)and Rapeseed (Brassica Campestris L.) From Co-contaminated Soil

Perfluoroalkyl substances(PFASs)have been worldwide used for many years in a variety of commercial and industrial products.Perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS)are typical PFASs which are detected frequently in environmental matrices wildlife and humans.They are persistent in the environment and have the ability of bioaccumulation and biomagnifications due to their strong binding potential to proteins,and display adverse effects on wildlife and human health.Heavy metals are ubiquitous in environmental matrices,such as air,surface water,soil and sediment and readily toxic to biota and humans through biomagnification.And so,the pollution of heavy metals has become a major concern of international community.The combined pollution of PFASs and Cd might occur in soil and lead to mutual effects on bioaccumulation and toxicity in terrestrial organism.A vegetation study was conducted to investigate the interactive effects of perfluoroalkyl substances(PFASs),including perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),and Cadmium(Cd)on soil enzyme activities,phytotoxicity and bioaccumulation of wheat(Triticum aestivum L.)and rapeseed(Brassica campestris L.)from co-contaminated soil.Soil urease activities were inhibited significantly but catalase activities were promoted significantly by interaction of PFASs and Cd which had few effects on sucrase activities.Joint stress with PFASs and Cd decreased the biomass of plants and chlorophyll(Chl)content in both wheat and rapeseed,and malondialdehyde(MDA)content,superoxide dismutase(SOD)and peroxidase(POD)activities were increased in wheat but inhibited in rapeseed compared with single treatments.The bioconcentration ability of PFASs in wheat and rapeseed were decreased,and the translocation factor of PFASs was decreased in wheat but increased in rapeseed with Cd additon.The bioaccumulation and translocation ability of Cd were increased significantly in both wheat and rapeseed with PFASs addition.These findings suggested important evidence that the co-existence of PFASs and Cd reduced the bioavailability of PFASs while enhanced the bioavailability of Cd in soil,which increased the associated environmental risk for Cd but decreased for PFASs.