Risk assessment microbial products

The ECPI approach has been adopted by the European Commission in their "Technical Guidance Document on the Risk Assessment of Notified New Substances" as the model for assessment of environmental exposure from additives in plastics. It is important to note, however, that due to the effect of ultraviolet degradation and microbial attack, a significant proportion of the emissions from flexible PVC consists of plasticizer degradation products. In these instances, therefore, the level of plasticizers appearing in the environment will be significantly less than indicated by the plasticizer loss data. 

In the selection of a microbial system and bioremediation method, some examination of the degradation pathway is necessary. At a minimum, the final degradation products must be tested for toxicity and other regulatory demands for closure. Recent advances in the study of microbial metabolism of xenobiotics have identified potentially toxic intermediate products (Singleton, 1994). A regulatory agency sets treatment objectives for site remediation, and process analysis must determine whether bioremediation can meet these site objectives. Specific treatment objectives for some individual compounds have been established. In other cases total petroleum hydrocarbons total benzene, toluene, ethyl benzene, and xylene (BTEX) or total polynuclear aromatics objectives are set, while in yet others, a toxicology risk assessment must be performed. 

Genetically engineered products are reviewed on a case-by-case basis to address any special questions that may arise. Most risk assessment considerations and methods for data development are similar to those established for naturally occurring microbial pesticide products. 

At present, there is an absence of generally accepted principles of risk assessment for microbial products, especially when their use involves direct release into the environment. For this reason, and... 

For prioritising actions both hazards (microbial contamination and faulty composition) were related to the frequency of administration. The top 10 of both frequency lists are taken into the risk assessment. The risk matrix puts the frequency of administration against the risk of contamination or the risk of faulty composition respectively (= Tables 21.4 and 21.5). These matrixes visualise which products have to be improved first. Risk reduction can be achieved by decreasing the number of steps, for example by pharmacy preparation of premixed preparations or prefilled syringes. 

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