PIREN-Seine programme, several chemicals were analysed in water samples.
Among them, the following oestrogens were especially analysed, the natural
oestrogens, E2 or its isoform α, oestrone (E1) and oestriol (E3) and the synthetic
one, ethinylestradiol (EE2), and their contribution to the oestrogenic potential of the
water column was studied. For this purpose, the oestrogenic potency of water
samples collected between February and November 2010 in Marnay-sur-Seine,
Bougival and Triel-sur-Seine was expressed in two ways: as biological EEQ in ng
E2-eq/L derived from the bioassay approach and as chemical EEQ in ng E2-eq/L,
corresponding to the sum of the relative biological potency to E2 of each oestrogen
multiplied by their respective concentration in the dissolved phase of water samples
[13]. Thus, the biological EEQs measured were compared to the chemical EEQ
estimated according to E2 (isoforms α and β), E1, E3 and EE2 concentrations
weighted by their respective oestrogenicity on MELN cells [12]. A good correlation
was highlighted between chemical and biological EEQs on all the three Seine axis
pilot sites, the correlation coefficient R values ranging from 0.84 for Marnay-surSeine to 0.99 for Bougival.
Other contaminants, known or suspected as endocrine disruptors, were monitored
during these water-sampling campaigns: phthalates, alkylphenols, polycyclic aromatic hydrocarbons (PAHs), PCBs, PBDEs and bisphenol A [12]. Among these
chemicals, only 4-nonylphenol and bisphenol A are proven endocrine disruptors,
with reference toxicological values established regarding their ED effects [14, 15].
For all water samples, the correlation between biological and chemical EEQs was
much weaker for 4-nonylphenol (R ¼ 0.57) and bisphenol A (R ¼ 0.73) than for
oestrogens (R ¼ 0.96), with E2 as the largest contributor by far to the oestrogenicity
of surface waters from the Seine River, followed by E1, in accordance with most
studies reviewed by [16]. E3 and EE2 were not detected in the water samples
collected in 2010, unlike in previous samples from the Orge catchment in 2007
[13]. Comparatively, bisphenol A and 4-nonylphenol contributed to a minor extent
(~2%) to the ED potential of Seine River organic contamination. A safe oestrogenic
equivalent value of 0.3 ng E2-eq/L, regarding steroid oestrogens, was based on the
assumption that these chemicals are responsible for more than 90% of in vitro
oestrogenicity of municipal wastewater treatment plant effluents [16]. The abovementioned results are in line with this consideration, and the proposed provisional
trigger value was exceeded by mean EEQ values measured for water samples from
downstream Seine River sites: Bougival (0.84 ng E2-eq/L) and Triel-sur-Seine
(0.55 ng E2-eq/L). In the latter campaigns (2011–2012), the trigger value was
exceeded only for water samples from Triel-sur-Seine, especially in June 2012,
showing an EEQ of 2.1 ng E2-eq/L.
Experience Gained from Ecotoxicological Studies in the Seine River and. . .
247
Among them, the following oestrogens were especially analysed, the natural
oestrogens, E2 or its isoform α, oestrone (E1) and oestriol (E3) and the synthetic
one, ethinylestradiol (EE2), and their contribution to the oestrogenic potential of the
water column was studied. For this purpose, the oestrogenic potency of water
samples collected between February and November 2010 in Marnay-sur-Seine,
Bougival and Triel-sur-Seine was expressed in two ways: as biological EEQ in ng
E2-eq/L derived from the bioassay approach and as chemical EEQ in ng E2-eq/L,
corresponding to the sum of the relative biological potency to E2 of each oestrogen
multiplied by their respective concentration in the dissolved phase of water samples
[13]. Thus, the biological EEQs measured were compared to the chemical EEQ
estimated according to E2 (isoforms α and β), E1, E3 and EE2 concentrations
weighted by their respective oestrogenicity on MELN cells [12]. A good correlation
was highlighted between chemical and biological EEQs on all the three Seine axis
pilot sites, the correlation coefficient R values ranging from 0.84 for Marnay-surSeine to 0.99 for Bougival.
Other contaminants, known or suspected as endocrine disruptors, were monitored
during these water-sampling campaigns: phthalates, alkylphenols, polycyclic aromatic hydrocarbons (PAHs), PCBs, PBDEs and bisphenol A [12]. Among these
chemicals, only 4-nonylphenol and bisphenol A are proven endocrine disruptors,
with reference toxicological values established regarding their ED effects [14, 15].
For all water samples, the correlation between biological and chemical EEQs was
much weaker for 4-nonylphenol (R ¼ 0.57) and bisphenol A (R ¼ 0.73) than for
oestrogens (R ¼ 0.96), with E2 as the largest contributor by far to the oestrogenicity
of surface waters from the Seine River, followed by E1, in accordance with most
studies reviewed by [16]. E3 and EE2 were not detected in the water samples
collected in 2010, unlike in previous samples from the Orge catchment in 2007
[13]. Comparatively, bisphenol A and 4-nonylphenol contributed to a minor extent
(~2%) to the ED potential of Seine River organic contamination. A safe oestrogenic
equivalent value of 0.3 ng E2-eq/L, regarding steroid oestrogens, was based on the
assumption that these chemicals are responsible for more than 90% of in vitro
oestrogenicity of municipal wastewater treatment plant effluents [16]. The abovementioned results are in line with this consideration, and the proposed provisional
trigger value was exceeded by mean EEQ values measured for water samples from
downstream Seine River sites: Bougival (0.84 ng E2-eq/L) and Triel-sur-Seine
(0.55 ng E2-eq/L). In the latter campaigns (2011–2012), the trigger value was
exceeded only for water samples from Triel-sur-Seine, especially in June 2012,
showing an EEQ of 2.1 ng E2-eq/L.
Experience Gained from Ecotoxicological Studies in the Seine River and. . .
247