Abstract:
Endocrine disrupting chemicals (EDCs) are ubiquitous in the environment and their
presence in water bodies is documented. They discharge into surface water (SW)
unmonitored, posing a threat to both aquatic and terrestrial lives. This is a challenge
as not all populations have access to treated drinking water (TDW). The EDC
contaminated serves as a route of exposure, together with ineffective treatment
plants. Given the complexity of the endocrine system, EDCs may mimic or
antagonise natural hormones or disrupt their synthesis, metabolism and excretion.
The associated health effects include testicular dysgenesis syndrome, metabolic
disorders and cancers. Policy and internationally standardised test methods are
however sti ll limited. This study therefore aimed to assess the suitability of two
assays used for screening estrogenic activity and one for androgenic activity in
different water sources.
The study consisted of two phases. In phase 1, water sample (tap, surface and
treated wastewater) were collected from a catchment area in Pretoria. The samples
and a spiked MilliQ laboratory water sample were extracted with solid phase
extraction (SPE) and sent to Germany for distribution to participating laboratories.
Samples (n=24) from six different countries were received to test for androgenic
activity in the MDA-kb2 reporter gene assay. In phase 2, SW and TDW samples
were collected from April 2015 until March 2016. The samples were filtered,
extracted using SPE and assayed with the YES assay, T47D-KBluc reporter gene
assay for estrogenic activity and MDA-kb2 reporter gene assay for androgenic
activity. In phase 1, androgenic activity was detected in 4 out of 24 (21%) samples and
ranged from 0.23 ± 0.040 ng/L to 0.008 ± 0.001 ng/L DHTEqs. In phase 2,
estrogenic activity was detected in 16 out of 24 (67%) SW samples 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 detection limit (dl) in the YES assay. Androgenic activity was
detected in 4 out of 24 (17%) SW samples, ranging from 0.0033 ± 0.0050 ng/L to
0.090 ± 0.040 ng/L DHTEqs. Androgenic and estrogenic activity was higher i n pretreatment
samples compared to post-treatment in both treatment plants. In phase 1, the MDA-kb2 reporter gene assay was successfully 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
estrogens detected 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 value for health risk assessments.
Detected androgenic activity was lower in TDW samples compared to the SW
samples supplying the two treatment plants indicating that they were both effective in
removing the androgenic activity detected. Few studies have reported androgenic
activity in tap water. This study strengthens the argument for using a battery of assays when monitoring
endocrine activity as EDCs occur at low concentrations in mixtures.
