Nanoparticles ( 100 nm) are becoming more prevalent in residential and industrial uses and may enter the environment through wastewater. Although lab studies have shown that nanoparticles can be toxic to various organ...Nanoparticles ( 100 nm) are becoming more prevalent in residential and industrial uses and may enter the environment through wastewater. Although lab studies have shown that nanoparticles can be toxic to various organisms, limited research has been done on the effects of nanoparticles in the environment. Environmental conditions such as pH and ionic strength are known to alter the biotoxicity of nanoparticles, but these effects are not well understood. The objectives of this research were to determine the impacts of silver nanoparticles (AgNP) on zebrafish in the pseudo-natural environment of a lab-scale constructed wetland, and to investigate wastewater remediation through soil and water treatment residual (WTR) adsorption of AgNPs. Concurrently, the effect of particle size on AgNP sorption was examined. Researchers exposed adult zebrafish in a lab-scale constructed wetland to concentrations of AgNP ranging from 0 - 50 mg AgNP/L and compared them to negative controls with no silver exposure and to positive controls with exposure to silver nitrate. The results suggest that aggregated AgNP do not impact zebrafish. Separately, sorption experiments were carried out examining three media - a wetland soil, a silt loam soil, and a WTR - in their capacity to remove AgNPs from water. The silt loam retained less AgNPs from solution than did the wetland soil or the WTR. In the WTR AgNPs were associated with sand size particles (2 mm - 0.05 mm), but in the wetland soil and silt loam, approximately half of the AgNPs were associated with the sand-sized particles, while the rest were associated with silt sized (~0.05 mm) or smaller particles. The larger sorption capacity of the wetland soil and WTR was attributed to their higher carbon content. The sorption data indicate that AgNPs adsorbed to soil and WTRs and support the idea that natural and constructed wetlands can remove AgNPs from wastewater.展开更多
文摘Nanoparticles ( 100 nm) are becoming more prevalent in residential and industrial uses and may enter the environment through wastewater. Although lab studies have shown that nanoparticles can be toxic to various organisms, limited research has been done on the effects of nanoparticles in the environment. Environmental conditions such as pH and ionic strength are known to alter the biotoxicity of nanoparticles, but these effects are not well understood. The objectives of this research were to determine the impacts of silver nanoparticles (AgNP) on zebrafish in the pseudo-natural environment of a lab-scale constructed wetland, and to investigate wastewater remediation through soil and water treatment residual (WTR) adsorption of AgNPs. Concurrently, the effect of particle size on AgNP sorption was examined. Researchers exposed adult zebrafish in a lab-scale constructed wetland to concentrations of AgNP ranging from 0 - 50 mg AgNP/L and compared them to negative controls with no silver exposure and to positive controls with exposure to silver nitrate. The results suggest that aggregated AgNP do not impact zebrafish. Separately, sorption experiments were carried out examining three media - a wetland soil, a silt loam soil, and a WTR - in their capacity to remove AgNPs from water. The silt loam retained less AgNPs from solution than did the wetland soil or the WTR. In the WTR AgNPs were associated with sand size particles (2 mm - 0.05 mm), but in the wetland soil and silt loam, approximately half of the AgNPs were associated with the sand-sized particles, while the rest were associated with silt sized (~0.05 mm) or smaller particles. The larger sorption capacity of the wetland soil and WTR was attributed to their higher carbon content. The sorption data indicate that AgNPs adsorbed to soil and WTRs and support the idea that natural and constructed wetlands can remove AgNPs from wastewater.
