Chemical monitoring and temporal variation in levels of endocrine disrupting chemicals (priority phenols and phthalate esters) from selected wastewater treatment plant and freshwater systems in Republic of South Africa

Abstract

This study presents a quantitative estimation of the simultaneous analysis of 11 priority phenols and six phthalate esters in surface water from five rivers collected from the upstream and downstream of wastewater treatment plants (WWTPs) that emptied their final effluents into the rivers. In addition, influents and effluents from the WWTPs were collected on a quarterly basis between April 2010 and March 2011. Kirstenbosch Bo- tanical Garden stream was used as a control site. Gas chromatography–mass spectrometry (GC–MS) was used for identification and quantification using N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA). Chemical analysis by GC–MS revealed the presence of DEP, POH, PCP, DEHP, DBP, BBP, 2,4-DMP and 2-NP as the most abundant congeners. Zandvliet WWTP showed to be the most polluted as it receives wastewater from the largest informal settlement in the city. Generally, concentration ranged from below de- tection limit (LOD) for most of the congeners to 34.520 mg l− 1 for DBP at Zandvliet WWTP. Also, statistical analysis showed correlation between levels of analytes in effluent and downstream water samples, an indica- tion of pollution from the WWTP. From the monitoring exercise, data obtained for most compounds analyzed showed that the congeners are effectively removed (approximately 80 to 100%) with the exception of 2-nitro phenol that was poorly removed. The production of 2,4-DMP is also noteworthy in the final effluent of all the investigated treatment plants.