摘要
Silver nanoparticles(AgNPs)have been widely used in medicine and consumer products.And it enters the river in dif-ferent ways,then finally converges to the ocean through the estuary.AgNPs polution can affect NO_(2)−and N_(2)O production by denitri-fiers in aquatic system.The effects of AgNPs on denitrification activity,nitrogen transformation and nitrous oxide(N_(2)O)emission were investigated in Dagu River Estuary(DRE)and Jiaozhou Bay(JZB).The results showed that the potential denitrification activity(PDA),NO_(3)−and NO_(2)−reduction rates decreased with an increase of AgNPs concentration in DRE and JZB.However,the N_(2)O ac-cumulation was significantly increased at AgNPs concentrations above 5 mg kg^(−1)in both areas,and the accumulation rate was greater in estuary than in bay(P<0.05).Moreover,the total bacterial count showed a slightly increasing trend with an increase of AgNPs concentration(P>0.05)in DRE and JZB.Importantly,the relative abundance of narG,nirS and nosZ gene in two areas decreased with the increase of AgNPs concentration,and the negative effect of AgNPs varied in order:nosZ>nirS>narG,inferring that the expression of denitrifying related genes could be significantly and differently inhibited by AgNPs addition.Thus,this study demon-strated that the inhibitory effect of AgNPs on different denitrification process,which may lead to the increase of inorganic nitrogen accumulation and N_(2)O realease.This study provides a scientific basis for the further studies of AgNPs on the ecological impact mechanism and environmental effects of offshore sedimentary environment.
基金
supported by the Special Project of Guangxi Science and Technology Base and Talent(GUI KE AD20297065)
the National Natural Science Founda-tion of China(No.U20A20103)
the National Major Pro-ject of Water Pollution Control and Management Tech-nology in China(No.2013ZX07202-007)
the Sci-ence and Technology Planning Projects of Beihai,Guang-xi,China(Nos.201995002,201995076,202082031,202082022 and 202082032).
