Novel hyphenation of DGT in-situ passive sampling with YES assay to ascertain the potency of emerging endocrine disruptors in water systems in New Zealand

This study represents the first attempt to investigate selected estrogenic compounds that include 17 alpha-ethyny-lestradiol (EE2), 17 beta-estradiol (E2) bisphenol A (BPA), and bisphenol AF (BPAF) along the drinkable water, from river-to-tap, and wastewater, from effluent-to-treated wastewater, treatment processes of the Hamilton City Council and the monitoring of the freshwater, from source-to-outfall, of the Waikato River in New Zealand. This was accomplished by the adoption of a novel combination of diffusive gradients in thin films (DGTs) in-situ passive sampling coupled with high-performance liquid chromatography/mass spectrometry analysis (HPLC/ MS) and the Yeast Estrogen Screen (YES). Estradiol equivalency quantities, integrated in time, were evaluated theoretically (cEEQ) by DGT-HPLC/MS and experimentally (EEQ) by DGT-YES assay. cEEQ and EEQ highlighted that primary treatments are not suitable for estrogens and bisphenolic plastics removal both at drinkable and wastewater treatment plants in Hamilton where they worsen the water quality in terms of estrogenicity making these pollutants more available in the water phase. All downstream sites monitored along the Waikato River showed higher cEEQ and EEQ, moreover the Waikato River water quality showed a moderate worsening moving from Taupo (source) to Tuakau (outfall). The most polluted sites were downstream of Hamilton city and Huntly township wastewater treatment plants that serve the main conurbations in the area. cEEQ and EEQ generally showed good agreement at low concentrations but differed substantially at more polluted sites where cEEQ consistently underestimated estrogenic potency, possibly due to DGT accumulation of estrogenic compounds not quantified by HPLC/MS.

Automated summary

This study investigates the presence of selected estrogenic compounds during the treatment processes of drinkable water and wastewater in Hamilton, New Zealand. The results indicate that the primary treatments used in the plants are not effective in removing estrogens and bisphenolic plastics, leading to a deterioration in water quality.