Methylmercury bioaccumulation in marine phytoplankton Methylmercury (MeHg) has long been recognized as an important contaminant in marine ecosystems. The largest bioconcentration step of MeHg in marine food webs is from the aqueous phase to phytoplankton. The first systematic comparison of MeHg bioaccumulation among six different algal species was conducted in this study, examining the influence of environmental factors on the uptake process and discussing subsequent biogeochemical implications. The result shows that passive transport seemed to be the primary pathway for most phytoplankton to acquire MeHg and was related to the surface-area-to-volume ratio of algal cells. Environmental conditions did not directly affect MeHg uptake except for the mixotrophic dinoflagellate which showed active uptake of MeHg. The presence of dissolved organic matter, especially those with a sulfur functional group (thiol), was confirmed to inhibit algal MeHg uptake. The algal MeHg uptake rates and bioconcentration factors in diverse algal species were calculated in this study and further applied to a global biogeochemical model describing Hg cycling in the marine environment.

Treatment of emerging contaminant 1,4-dioxane in groundwater in Long Island, New York, using advanced oxidation processes 1,4-Dioxane (1,4-D) is a likely human carcinogen and a widespread drinking water contaminant across the U.S. Conventional water treatment approaches do not effectively remove 1,4-D, and hence, advanced oxidation processes (AOPs), such as UV/H2O2, are increasingly being employed by water suppliers. A series of systematic studies to assess the impact of groundwater quality on treating environmentally relevant levels of 1,4-D was performed in this study. Typical groundwater quality parameters (pH, alkalinity, natural organic matter (NOM), nitrate, and Fe) on the performance of UV/H2O2 treatment and the formation of associated byproducts were investigated simultaneously. With the lab-scale controlled experiments, a multiple linear regression model using water quality data was developed to predict the performance of UV/H2O2 treatment of actual groundwater. The model output agreed with field observations in predicting the rate constants for removing 1,4-D from field groundwater samples. The results of this study should assist with the design and evaluation of pilot- and full-scale UV/H2O2 treatment systems and should be of interest to a broad audience of environmental scientists, various regulatory agencies, and public health professionals.