Summary and recommendation
Table 7 presents a summary of methods to determine biodegradation of chemicals. There are no specific limitations for ionisable compounds. Details and references are given in Appendix E.
The preferred strategy is to demonstrate that a test substance is ‘readily biodegradable' and that no further fate testing is required. This strategy, however, is not particularly relevant for all commodity products, especially for products designed for their stability and shelf life, such as pharmaceuticals. In such instances, the next best approach is to determine the chemical specific kinetic data such that the PEC for that particular compartment (sludge, water, soil and sediment) may be revised for the observed biodegradation. This provides the necessary information to estimate PEC/PNEC ratio, or risk quotient for the ERA. In instances where further refinement is necessary, and only then, does one proceed to simulation testing targeted to that particular commodity item and the specific conditions of the release scenario.