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Hormone and hormone mimicking activity in sewage effluent, surface water and treated drinking water Laetitia Slabbert. Results generated by several Water Research Commission studies Various institutions participated in the studies:
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Hormone and hormone mimicking activity in sewage effluent, surface water and treated drinking waterLaetitia Slabbert
Results generated by several Water Research Commission studies Various institutions participated in the studies: CSIR, University of Stellenbosch, AMPATH, University of Pretoria, Environment Canada, Agricultural Research Council, SABS
Outline • Background: endocrine disruption • Study area and sampling sites • Sample preparation • Detection methodologies • Results • Conclusions
BackgroundHormone (endocrine) disruption – effect of natural and man-made chemicals on the endocrine systems of wildlife and man
Wildlife: reproductive abnormalities; decreased fertility; impaired thyroid and immune system functionHumans: Effects on prenatal neurological development, neuro-endocrine and immune system function; decreased fertility; prevalence of testicular, uterine and breast cancer
Natural EDCs: phyto- and mycoestrogens; human estrogens (17β-estradiol) and metabolites (estriol, estrone)
EDCs enter the water environment via effluent discharge and run-off
Sewage treatment plants - important sources of natural and synthetic estrogen contamination of aquatic environment • Pregnant females: 30 mg estrogen per day • Conjugates of sulphuric and glucuronic acids • Bacteria (E. coli) can catabolise metabolites to free steroids • Faeces contains large numbers of E. coli
Effluent samples • 24 h composite samples • 5 consecutive days • Before chlorination
Surface water • Hartebeespoort Dam • Rietvlei Dam • Vaal River Grab samples on four occasions
Water samples • Grab samples • Four sampling occasions
Sample preparation In vitro biological assays and estrogen analysis – solid phase extraction, residue dissolved in organic solvent Liquid-liquid extraction used for residue analysis In vivo test – effluent sample
Detection methodologies • Biological tests: • In vitro tests • Recombinant yeast screen (YES) • Estrogen receptor-mediated chemical activated luciferase gene expression assay (ER-CALUX) • Primary rainbow trout hepatocyte (PRTH) test • In vivo test • 8- and 14-day zebrafish exposure • Chemical analysis: • GC-MS
YES • Human estrogen receptor • Binding to receptor induces expression of the lac-Z gene carried by expression plasmids • Leads to activation of ß-galactosidase • Metabolism of yellow chlorophenol red-ß-D-galactopyranosid (CPRG) to a red product – assessed with a micro-spectrophotometer
17ß-estradiol 3 days 7 days 10 days Incubation time
YES 17β-estradiol EC50’s 7.15-22.07 ng/ℓ
ER CALUX assay • Human breast cancer cells • Exposure to estrogens - binding to endogenous ER • Leads to induction of luciferase gene • Assayed by lysing cells, adding substrate luciferin and measuring light output
PRTH test - Estrogens bind with estrogen receptor in cells, which will trigger vitellogenin (VTG) production. VTG is a precursor of egg yolk - VTG will accumulate in the extracellular medium in 96-well microplates - Measured indirectly via alkali-labile phosphate groups using a micro-spectrophotometer
Zebrafish test Sewage samples • Adult male fish exposed in aquaria for 8 days • Blood collected from tail vein, centrifuged and plasma used for VTG ELISA (enzyme linked immuno sorbent assay) in 96-well microplates • Histological analysis on gonads to determine sex Water samples • Juvenile fish exposed for 14 days • Homogenates used for VTG ELISA in 96-well microplates
Female specimen - Male testicular tissue vitellogenic follicels
Comparison of in vitro test results with values reported in literature Sewage effluent • 0.2-25 ng EEQ/ℓ E-screen – Germany • <16 ng EEQ/ℓ YES and ER-CALUX – Netherlands • <1.0-147 ng EEQ/ℓ YES – USA • 4-35 ng EEQ/ℓ modified YES – Japan • As high as 23.5 ng EEQ/ℓ YES – Study by Arijs on points of discharge in rivers/streams in the Pretoria-Johannesburg-Vereeniging area
Comparison of in vitro test results with values reported in literature Surface water
Sewage effluent – estrogenicity (males: >80%) 4 3 2 Plasma VTG concentration (µg/mℓ) 1 0 Control H1 H2 H3 H4 H5 Females Exposure Groups
Triazine and p-nonyl phenol concentrations (ug/ℓ) in river and dam water
Triazine and p-nonyl phenol concentrations (ug/ℓ) in final drinking water