| Popis: |
Parabens are ubiquitous, being found in surface waters around the world. Although little is known about the release of paraben transformation products and fate of transformation products in surface water. This study evaluates both parabens and paraben transformation products in the Brazos River upstream and downstream of a wastewater facility located in Waco, Texas. Concentrations of thirteen compounds were reported in this study, five parent parabens and eight paraben disinfection byproducts. Analyte concentrations were spatially evaluated to determine if release of wastewater effluent effects their concentrations in the river. Two Brazos River tributaries were also sampled to determine if they released parabens and related compounds to the Brazos. Sampling occurred weekly for one year with at least 40 samples collected at each site. Analyses were completed for both yearly and seasonal data. Sites downstream of wastewater treatment outfalls had lower concentrations of methyl paraben during the yearly analysis and across multiple seasons in the seasonal analysis. Para-hydroxybenzoic acid was the compound present in greatest concentration at most sites across most seasons, and spatial changes in para-hydroxybenzoic acid varied by season, with no identifiable trends. Dichlorinated paraben concentrations increased in the river at sites downstream of wastewater treatment. Concentration increases indicate that wastewater effluent contains sufficiently high dichlorinated paraben concentrations to effect concentrations downstream of effluent discharges. Dichlorinated species also persisted in the environment, with no significant decreases at sites further downstream during any season. Methyl paraben concentrations decreased at the site furthest downstream while dichlorinated methyl paraben concentrations remained stable showing that the dichlorinated species degrade slower than their respective parent paraben. Due to the dichlorinated species being released in higher concentrations in effluent than parents and being more resistant to degradation, the dichlorinated parabens are more likely to environmentally relevant than are parent parabens. |
