Publication Abstract

The toxicological impacts of oil and chemically dispersed oil: UV mediated phototoxicity and implications for environmental effects, statutory testing and response strategies

The toxicological impacts of oil and chemically dispersed oil:  UV mediated phototoxicity and implications for environmental effects, statutory testing and response strategies

M.F. Kirby, B. Lyons, J. Barry and R.J. Law

The threat of oil-based hydrocarbon contamination via spills and other sources in the aquatic environment and their subsequent treatment with chemical dispersants remains a very real and highly emotive issue. It is well documented that ultra-violet (UV) light can enhance or induce the toxic effects of certain environmental contaminants (termed phototoxicity). Among those contaminants of primary concern are the polycyclic aromatic hydrocarbons (PAHs). Numerous laboratory studies have now demonstrated that the toxicity of PAHs increases 2 to >1000 times in the presence of UV (Arfsten et al., 1996 and Wernersson, 2003). Pelletier et al. (1997) reported that specific components of oil (fluoranthene, pyrene and anthracene) and four oil products were 12 to >50,000 times more toxic (LC₅₀ tests) to marine invertebrate juveniles (Mysidopsis bahia) and bivalve larvae and embryos (Mulinia lateralis) when compared with parallel tests omitting UV light. Similar studies were conducted using the freshwater crustacean, Daphnia magna, to screen for the phototoxic potential of 22 water accommodated fractions (WAF) derived from petroleum based products (Wernersson, 2003). In this study 16 of the 22 WAFs demonstrated significantly increased toxicity in the presence of UV-light. Lyons et al. (2002) highlighted the ability of certain PAHs to exhibit photo-induced toxicity at levels of UV-light typically found to penetrate the upper 5 m of European surface waters. Additional studies, carried out as part of the 2001 BECPELAG ICES/IOC sea-going workshop, demonstrated that sea surface microlayer samples collected from around the Statfjord oil field displayed enhanced phototoxicity to embryos of the pacific oyster (Crassostrea gigas) when exposed to environmentally relevant levels of UV-light (Lyons et al., 2006). While it is noted that phototoxicity is not restricted to PAHs (the same phenomenon has been demonstrated for other pollutants including pesticides (Ankley et al., 1998), munition waste products and metals (Arfsten et al., 1994)), it is clear from the literature that this group of ubiquitous contaminants offer the greatest cause for concern for environmental damage.

Reference

M.F. Kirby, B. Lyons, J. Barry and R.J. Law (2007) The toxicological impacts of oil and chemically dispersed oil:  UV mediated phototoxicity and implications for environmental effects, statutory testing and response strategies. Marine Pollution Bulletin, 54: 472-475

M.F. Kirby*, B. Lyons*, J. Barry* and R.J. Law*

Marine Pollution Bulletin, 54(4): 472-475