Environmental transport and fate of endocrine disruptors from non-potable reuse of municipal wastewater

This project was designed to investigate the important but virtually unstudied topic of the subsurface transport and fate of Endocrine Disrupting Compounds (EDCs) when treated wastewater is used for landscape irrigation (non-potable water reuse). Although potable water reuse was outside the scope of this project, the investigation clearly has relevance to such water recycling practices. The target compounds, which are discussed in the following section and include EDCs such as 4-nonylphenol (NP) and 17{beta}-estradiol, were studied not only because of their potential estrogenic effects on receptors but also because they can be useful as tracers of wastewater residue in groundwater. Since the compounds were expected to occur at very low (part per trillion) concentrations in groundwater, highly selective and sensitive analytical techniques had to be developed for their analysis. This project assessed the distributions of these compounds in wastewater effluents and groundwater, and examined their fate in laboratory soil columns simulating the infiltration of treated wastewater into an aquifer (e.g., as could occur during irrigation of a golf course or park with nonpotable treated water). Bioassays were used to determine the estrogenic activity present in effluents and groundwater, and the results were correlated with those from chemical analysis. In vitromore » assays for estrogenic activity were employed to provide an integrated measure of estrogenic potency of environmental samples without requiring knowledge or measurement of all bioactive compounds in the samples. For this project, the Las Positas Golf Course (LPGC) in the City of Livermore provided an ideal setting. Since 1978, irrigation of this area with treated wastewater has dominated the overall water budget. For a variety of reasons, a group of 10 monitoring wells were installed to evaluate wastewater impacts on the local groundwater. Additionally, these wells were regularly monitored for tritium ({sup 3}H). Overall volumes of irrigation water have been recorded along with total flows through the Livermore Water Reclamation Plant (LWRP). The Environmental Protection Department at LLNL has carefully monitored {sup 3}H effluent leaving the laboratory for many years. For two years preceding the initiation of this project, Grayson and Hudson, working with LWRP staff, had demonstrated that these data could be used to accurately calculate the {sup 3}H concentration in the applied irrigation water as a function of time. This was accomplished by performing two carefully monitored tritium releases from LLNL and following the {sup 3}H through the LWRP. Combining these data with our ability to age-date groundwater using the {sup 3}H-{sup 3}He age-dating technique, it was possible determine both the age and the degree of dilution from other water sources. This information was critical in the evaluation of observed concentrations of trace organic compounds from wastewater. The project included the following tasks: (1) Develop a conceptual model for Las Positas Golf Course (LPGC) irrigation that integrates existing meteorological, hydrologic, and environmental monitoring data. (2) Develop analytical methods (involving solid-phase extraction and isotope dilution LC/MS/MS) for the specific and sensitive measurement of target EDCs. (3) Develop a bioassay for estrogenic activity for application to effluent and groundwater samples. (4) Perform detailed hydrological evaluation of groundwater taken from LPGC. (5) Characterize the source term for target EDCs in wastewater. (6) Evaluate the utility of EDCs as source tracers for groundwater contamination. « less