Estrogenic and Anti-estrogenic Activity Present in Wastewater Effluent and Reclaimed Water
Author | : Otakuye Conroy |
Publisher | : |
Total Pages | : 654 |
Release | : 2006 |
ISBN-10 | : OCLC:659747562 |
ISBN-13 | : |
Rating | : 4/5 (62 Downloads) |
Book excerpt: Water demand in the semiarid southwestern United States is approaching sustainable limits. Treated wastewater is frequently the last major untapped water resource. Secondary effluent contains traces of hormones and other endocrine disrupting contaminants. In Tucson, the vast majority of treated wastewater is either discharged to the Santa Cruz River (which would otherwise be dry for 10-11 months of the year, or infiltrated for groundwater recharge at the Sweetwater Recharge Facility (SRF). Soil aquifer treatment at the SRF is relied upon to polish effluent prior to its recovery and reuse for landscape irrigation. There were three primary venues for the study described here: (i) the Roger Road Wastewater Treatment Plant (RRWTP), (ii) the SRF, and (iii) the Santa Cruz River. Secondary treatment at the RRWTP lowered the estrogenic activity of wastewater(influent to effluent) by 35-60 percent. Residual estrogenic activity in RRWTP effluent decreased to near zero over a 24-hr detention period in the SRF infiltration basins, while anti-estrogenic activity increased over the same period. Water collected from the underlying unconfined aquifer, however, was again estrogenic, probably due to the selective removal of anti-estrogens during percolation. In the effluent-dependent Santa Cruz River, estrogenic activity decreased continuously from the plant outfalls to a point about 25 miles downstream where estrogenic activity reached the limit of detection. A corresponding increase in antiestrogenic activity was evident. Monitoring wells along the stream produced levels of 24 estrogenic activity that were related to the fraction of wastewater effluent in respective samples (determined by the boron isotope ratio). The yeast estrogen screen (YES) procedure was modified by lysing the yeast after reporter gene expression to establish the dependence of bioassay response on dye transport kinetics. It was determined that β-galactosidase remains primarily inside the cell throughout the normal YES procedure. Furthermore, the rate of color development was sensitive to trans-membrane transport of the dye substrate as well as the estrogen content of the waters tested. The modified (LYES) procedure was capable of detecting both estrogenic and anti-estrogenic activity in samples from effluent dependent streams.