Impairments of Endocrine Functions: Case Studies - Ecological Biomarkers: Indicators of Ecotoxicological Effects - page 230

9.2 Occurrence and Effects of Estrogenic and
Antiandrogenic Compounds in Seine Estuary
9.2.1 Seine Estuary: A Heavily Modified Environment
Before its industrial management in the mid-nineteenth century, the Seine was a shal-
low river surrounded by large wetlands that regulated its hydrological low and allowed
the reproduction and development of many species. Significant changes have been made
since then to ensure the navigability of the river and to promote the industrial and urban
development of the area. Major drainage works and embankments along the Seine estuary
enabled the port of Le Havre and the adjacent industrial area to increase significantly in
size. The estuary was framed with artificial banks (dikes) at the cost of regular dredging
to maintain a shipping channel. The facilities reduced the volume of the estuary, altered
its hydrosedimentary regulation, and significantly reduced the intertidal area, which
decreased from 130 km 2 in 1834 to only 31 km 2 in 1978 (Avoine 1981). Since then, deposition
of sediments in the downstream part of the estuary has led to a very rapid increase of the
salt marsh at the expense of mudflats that can no longer fulfill their ecological functions
(water treatment, habitat essential for protection and reproduction of living species).
The Seine estuary now suffers from significant anthropogenic pressure. It is the natu-
ral receptacle of a watershed of nearly 80,000 km 2 , which houses 18 million people (more
than a quarter of the French population), 40% of French industries, 50% of the national
river traffic, and approximately 50,000 km 2 of agricultural land dedicated to intensive pro-
duction (Guézennec 1999). This human pressure results in high levels of contaminants
released into the air and water (Minier et al. 2006a; Motelay-Massei et al. 2007; Amiard
et al. 2009). Indeed, the national monitoring network of the French coast, which conducts
regular chemical measurements, clearly indicates the Seine estuary to be a hotspot of pol-
lution at national level (Claisse 1989; RNO 2006). Identification and quantification of indus-
trial compounds banned since the 1980s, such as polychlorinated biphenyls, show that
levels in tissues of zebra mussels ( Dreissena polymorpha ) living in the Seine estuary are
still among the highest in the world. Similarly, the concentrations of polycyclic aromatic
hydrocarbons are particularly high, resulting in elevated toxicity and genotoxicity (Minier
et al. 2006a). Many “classical” contaminants such as mercury, silver, and dioxins are also
at levels of concern (RNO 2006).
Recently, scientific and general public awareness of contaminant impacts on wildlife
and humans and the development of new analytical techniques, have led to further moni-
toring programs and the discovery of new contaminants in the environment. It appears
that pharmaceutical compounds, such as analgesics, antidepressants, synthetic hormones,
antibiotics, and lipid-lowering drugs are regularly discharged and found in sediment and
water of the Seine (Budzinski et al. 2005). Yet, the toxicity of these mixtures of contami-
nants has never been evaluated and needs to be addressed.
9.2.2 Estrogenic and Antiandrogenic Contamination of Seine Estuary
Endocrine disrupters are compounds that exert a deleterious effect on organisms, not
through a classical mechanism of toxicity but by altering an existing control system in
the body, the endocrine system. By interfering with this system, endocrine disrupting
compounds (EDCs) affect the essential coordination and organization of living organ-
isms, thus having major consequences on reproduction or development (see Chapter 8).