Bioanalytical tools (in vitro bioassays) are finding increasing utility as screening tools because the chemical nature of endocrine activity in a sample may be unknown and/or difficult to quantify. This is particularly true for those less studied endocrine endpoints, where the causative chemicals are often unknown.
The EDC Toolbox 2 project continued and expanded on previous GWRC efforts to develop and validate methods to measure estrogenic activity in water to include a range of substantially less well-studied endocrine endpoints.
The project overall:
- Concluded that in an ecological context, endocrine active compounds in water can pose a risk to living organisms in the receiving environment;
- concluded that in a human health context, the concentration of endocrine active compounds in drinking water is unlikely to produce significant endocrine effects in humans;
- confirmed that using bioanalytical tools alongside conventional chemical screening provides a richer and greatly improved assessment of water quality; and
- with regards to thyroid activity in water, determined that thyroid receptor reporter gene assays were not suitable to detect thyroid activity in environmental water samples; that TPO inhibition and TTR-FITC assays appeared more promising but that the possible interference of natural organic matter in water samples needed to be investigated first; and that the in vivo Xenopus Embryonic Thyroid Assay was the only assay currently able to detect (low) thyroid activity in waste and surface waters.
Some important knowledge gaps were identified, in particular
- the need to develop a wider range of effect-based trigger values for bioassays to anchor bioassay results into a risk context;
- the need to better understand the potential ecological risk and to confirm the results, which were based on a limited number of grab samples; and
- the need to better understand the effect of co-occurrence of agonists and antagonists in water samples on in vitro bioassay analysis, and test the influence of natural organic matter on the responses of the TPO inhibition and TTR-FITC assays.
Leusch, F.D.L., Neale, P.A., Arnal, C., Aneck-Hahn, N.-H., Balaguer, P., Bruchet, A., Escher, B.I., Esperanza, M., Grimaldi, M., Leroy, G., Scheurer, M., Schlichting, R., Schriks, M., Hebert, A. (2018) Analysis of endocrine activity in drinking water, surface water and treated wastewater from six countries. Water Research: 139, 10-18.
Leusch, F.D.L., Aneck-Hahn, N.H., Cavanagh, J.-A.E., Du Pasquier, D., Hamers, T., Hebert, A., , Scheurer, M., Simmons, S.O., Schriks, M. (2018) Comparison of in vitro and in vivo bioassays to measure thyroid hormone disrupting activity in water extracts. Chemosphere: 191, 868-875.
Leusch, F.D.L., Neale, P.A., Hebert, A., Scheurer, M., Schriks, M., (2017) Analysis of the sensitivity of in vitro bioassays for androgenic, progestagenic, glucocorticoid, thyroid and estrogenic activity: Suitability for drinking and environmental waters. Environment International: 99, 120-130.