Abstracts Category : Other

Thesuitability of estrogen and androgen bioassays for the measurementof endocrine activity in different water matrices

by Silindile Ngcobo

Endocrine disrupting chemicals (EDCs) are ubiquitousin the environment and their presence in water bodies isdocumented. They discharge into surface water (SW) unmonitored,posing a threat to both aquatic and terrestrial lives. This is achallenge as not all populations have access to treated drinkingwater (TDW). The EDC contaminated serves as a route of exposure,together with ineffective treatment plants. Given the complexityof the endocrine system, EDCs may mimic or antagonise naturalhormones or disrupt their synthesis, metabolism and excretion. Theassociated health effects include testicular dysgenesis syndrome,metabolic disorders and cancers. Policy and internationallystandardised test methods are however sti ll limited. This studytherefore aimed to assess the suitability of two assays used forscreening estrogenic activity and one for androgenic activity indifferent water sources. The study consisted of two phases. Inphase 1, water sample (tap, surface and treated wastewater) werecollected from a catchment area in Pretoria. The samples and aspiked MilliQ laboratory water sample were extracted with solidphase extraction (SPE) and sent to Germany for distribution toparticipating laboratories. Samples (n=24) from six differentcountries were received to test for androgenic activity in theMDA-kb2 reporter gene assay. In phase 2, SW and TDW samples werecollected from April 2015 until March 2016. The samples werefiltered, extracted using SPE and assayed with the YES assay,T47D-KBluc reporter gene assay for estrogenic activity and MDA-kb2reporter gene assay for androgenic activity. In phase 1,androgenic activity was detected in 4 out of 24 (21%) samples andranged from 0.23 0.040 ng/L to 0.008 0.001 ng/L DHTEqs. Inphase 2, estrogenic activity was detected in 16 out of 24 (67%) SWsamples in the T47DKBluc reporter gene assay and ranged from 0.31 0.05 pg/L to 10.51 5.74 pg/L EEqs. It was below the detectionlimit (dl) in the YES assay. Androgenic activity was detected in 4out of 24 (17%) SW samples, ranging from 0.0033 0.0050 ng/L to0.090 0.040 ng/L DHTEqs. Androgenic and estrogenic activity washigher i n pretreatment samples compared to post-treatment in bothtreatment plants. In phase 1, the MDA-kb2 reporter gene assay wassuccessfully applied to water samples from different sources.Androgenic activity was highest in treated wastewater. In phase 2,treatment plants proved to be effective in removing estrogensdetected in the SW samples, as the TDW samples were below the dl.Estrogenic activity is within the ranges reported in other studies.Positive samples were below the 0.7 ng/L proposed trigger valuefor health risk assessments. Detected androgenic activity waslower in TDW samples compared to the SW samples supplying the twotreatment plants indicating that they were both effective inremoving the androgenic activity detected. Few studies havereported androgenic activity in tap water. This study strengthensthe argument for using a battery ofAdvisors/Committee Members: Aneck-Hahn, Natalie H. (advisor), De Jager, Christiaan (coadvisor).