Toxicity of nonylphenol on the cnidarian Hydra attenuata and environmental risk assessment

Abstract

Alkylphenols and their derivatives, alkylphenol polyethoxylates (APEs), are synthetic chemicals of concern owing to their endocrine properties. Nonylphenol (NP) is a critical APE metabolite because of its recalcitrance to biodegradation, toxicity, and ability to bio-accumulate in aquatic organisms. Studies of NP effects in vertebrates demonstrated estrogenic disrupting properties in fish, birds, reptiles, and mammal cells in which NP displaces the natural estrogen from its receptor. Less is known on its toxicity toward invertebrates. Effects on reproduction have been reported, but toxicity on development has been poorly documented thus far. We investigated NP toxicity on survival and regeneration of the freshwater coelenterate Hydra attenuata. Hydra is known for its regenerative capacity and its sensitivity to chemical pollution. It has been used for over 20 years to screen for teratogenicity of chemicals (Johnson et al. (1982) Teratog Carcinog Mutagen 2:263-276). Our results showed that hydra appeared as one of the most sensitive species to acute and chronic toxicity of NP compared to several freshwater invertebrates. Regeneration was disrupted at NP concentrations lower than those affecting survival. Toxicity thresholds of NP for aquatic vertebrates and invertebrates are also reported and discussed in the context of environmental risk assessment and of water quality objectives recommended for surface waters in industrialized countries. NP levels have decreased during the last decade because of a voluntary agreement of surfactant producers and users. At present, concentrations of NP found in surface waters are far below 1 microg/L in Europe, but can reach several microg/L when wastewater treatment plant inefficiency occurs.

Hydra, a model system for environmental studies

“…Hydra have been successfully used to examine the teratogenic potential of several chemicals including effluents and water samples (Fu et al, 1991, Fu et al, 1994 and various chemicals (Johnson et al, 1986;Mayura et al, 1991;Yang et al, 1993;Bowden et al, 1995,) including endocrine disrupting compounds Pachura-Bouchet et al, 2006) and pharmaceuticals Quinn et al, 2008b;Quinn et al, 2009). Good correlation was found between the in vitro Hydra regeneration assay and teratogenicity in vivo, as reported by Bowden et al, (1995) and Wilby and Tesh (1990), who proposed it as a screening tool for teratogenicity.…”

“…Traditionally Hydra were used to assess the acute and regenerative toxicity of metals but organic compounds including more recently pharmaceuticals and nanomaterials have also been investigated (see section 4 below). Initially Hydra were used in toxicity tests on their own (Johnson et al, 1982;Blaise and Kusui, 1997;Beach and Pascoe, 1998;Pachura-Bouchet et al, 2006) and later as part of a bioassay battery of organisms (Arkhipchuk and Malinovskaya, 2002). The use of a battery of bioassays for the evaluation of complex environmental samples has been widely recommended as superior to a single bioassay, since it is unlikely that a single bioassay will be responsive to all possible toxicants (Clarke and Barrick, 1990).…”

“…vulgaris (previously named H. attenuata) is reported to be one of the most sensitive species to acute and chronic toxicity of the endocrine disrupting compound 4-nonylphenol compared to several freshwater invertebrates (Pachura-Bouchet et al, 2006). The toxicity recorded for Hydra with a 96 hour LC 50 of 97.5 mg/L and a "no observed effect concentration" (NOEC) for tentacle morphology of <25 mg/L, occurred at concentrations that are representative of those at polluted sites (Pachura et al, 2005).…”

Endocrine disruptors that disrupt the transcription mediated by androgen receptor

“…[1][2][3][4][5][6][7] Such environmental chemicals are known as endocrine disruptors. The Organization for Economic Co-operation and Development (OECD) defines endocrine disrupters as follows: an endocrine disrupter is an exogenous substance that causes adverse effects in an intact organism, or its progeny, consequent to changes in endocrine function.…”

Perspectives and approaches in nanotoxicology research

“…Some studies have examined the toxicity and effects of compounds such as nonylphenol or bisphenol A on the cnidarian, Hydra (Pachura-Bouchet et al, 2006;Pascoe et al, 2002). Analysis of their morphology, developmental stages, molecular events and the genetics of these species may represent models for probing nanoparticle toxicity as suggested in this issue by Ambrosone and Tortiglione.…”