Effluent C - untreated refinery wastewater

The high salinity of this sample meant that many of the chemical analyses were affected by chloride ion (Cl-) interference (Table 10.6). This, initially at least, 

The toxicity of effluent C to Microtox was far greater than the other effluents, with 15 min EC50 values for day 0 ranging between 0.19 and 0.37% of the effluent (Table 10.7). A similar level of toxicity was found with the oyster embryo test, 

For the oyster and Microtox tests, the day 0 EC50 values for the diluted effluent were not as would have been anticipated on the basis of dilution alone. For example, the oyster embryo EC50 value for the diluted effluent was 22% and therefore was 50-fold different from the neat effluent, and the Microtox tests were 30-fold different. These data indicate that the process for diluting and preparing the effluent 

Incorporating combined biodegradation and toxicity studies can improve both hazard and risk assessment of complex organic effluents such as those assessed in this study. For these effluents conventional analysis alone will reveal little about their toxicity, let alone the persistence of organic components. Therefore whole 

One of the key concerns facing regulators is that any toxicity discharged will be recalcitrant ( hard ) and, even if initial toxicity is diluted below any PNEC, effects may occur as toxic material builds up in the environment. Consequently, some regulators are interested in reducing the potential of effluents to cause a problem by reducing the amount of toxicity discharged (a hazard based approach) irrespective of the risks posed. 

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Effluent C - untreated refinery wastewater. The sample was split into two. One batch was supplemented with 1 ml/l each of OECD mineral salt medium and... 

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