MICROCONSTITUENTS OF EMERGING CONCERN IN RECLAIMED WATER AND BIOSOLIDS: CONSIDERATIONS FOR GROUNDWATER QUALITY

Use of reclaimed wastewater and biosolids for beneficial reuse has been widely practiced in the US for several decades. In recent decades, trace amounts of natural and synthetic estrogens and other emerging contaminants have been identified in effluent and biosolids from wastewater treatment plants. This challenges the continued and expanded reuse of these residuals due to growing public and environmental health concerns. While many studies have focused on evaluating concentrations of microconstituents of emerging concern (MECs) in the liquid phase, less attention has been paid to the extent the solid phase acts as a sink for these compounds, many of which are hydrophobic. Like reclaimed water, biosolids are a potential source of estrogens, pharmaceuticals and other emerging contaminants to the environment. They are increasingly used in landscaping, land reclamation and agriculture, and as such may be an important and widespread source of these contaminants of concern to both surface and groundwater.An understanding of the types and concentrations of MECs in reclaimed water and biosolids will provide direction for studies on the mobility and persistence of these compounds in the environment via leaching from soils, runoff into surface water, and association with sediments. This paper describes two studies to assess the occurrence and concentrations of over 100 MECs in 1) reclaimed water intended for indirect potable reuse via direct injection, and 2) in biosolids resulting from wastewater treatment. Results of these studies can be used to assess potential affects on groundwater.