**2. Metabolism of insecticides**

In fish, insecticides are readily converted into more polar compounds through biotransfor‐ mation and stored in the bile until their excretion. In general, detoxification process involves two phase, functionalization (phase I) and conjugation (phase II). The first biotransformation step (phase I) adds oxygen to the insecticides structure and the second step (phase II) conjugates the oxygenated product with and endogenous water-soluble small molecule present in the cell. The final products are highly water-soluble conjugates that are easier to eliminate than the parent compounds.Although, recently, anti-porter activity (p-glycoprotein or multidrug resistance) has been defined as the Phase III detoxification system, there is no exactly information about this detoxification system in fish.Classic detoxification pathways of insecticides in aquatic organisms are presented in Table 1.
