Gorham-Test is an alternative approach used to assess PAHs as there is no CEFAS - Action Levels 2 for PAHs. This is best described in CEFAS' Science Series - Aquatic Environment Monitoring Report no. 63 - Monitoring of the quality of the marine environment - 2008–2010

At present there is no UK legislation regarding the acceptability of levels of PAHs found in marine sediments. Cefas currently has action level limits for contaminants such as trace elements and PCBs in dredged material for possible disposal to sea, but none currently for PAHs. Reviews of the approaches taken in other countries to the development of sediment quality guidelines (SQGs) has indicated that the most promising of the currently available co-occurrence methods is the Effects Range Low/Effects Range Median (ERL/ERM) methodology, which is founded on a large database of sediment toxicity and benthic community information (Long et al., 1998; Rowlatt et al., 2002).munity information (Long et al., 1998; Rowlatt et al., 2002).

The ERL/ERM methodology derives SQGs representing, respectively, the 10th and 50th percentiles of the effects dataset, and these are usually derived for individual parent PAH compounds. In a regulatory context, where SQGs are to be used as informal (non-regulatory) benchmarks to aid in the interpretation of sediment chemistry (Long et al., 1998), this becomes complicated when a large number of individual PAH compounds are determined, as is usually the case and was also in this study.

This has led to separate ERL/ERM derived SQGs being set for ‘Low molecular weight PAHs’ and ‘High molecular weight PAHs’ (Gorham-Test, 1998). In this context, LMW PAH includes the 2- and 3-ring PAH compounds naphthalene, monomethyl naphthalenes, acenaphthene, acenaphthylene, fluorene, phenanthrene and anthracene, primarily oil-derived compounds; HMW PAH includes the 4- and 5-ring PAH compounds fluoranthene, pyrene, benzaanthracene chrysene, benzoapyrene and dibenza,hanthracene, primarily combustion-derived compounds. Although a wider suite of PAH is determined routinely for both licensing and monitoring purposes, these subsets can be considered as toxicity markers for the PAH as a whole. The ERL and ERM concentrations for low molecular weight PAHs (LMW PAH) and high molecular weight PAHs (HMW PAH) applied to this assessment are given below.

PAH compoundsERLERM
LMW PAH5523,160
HMW PAH1,7009,600

EPA EPA/906/R-98/00