This chapter is a review of literature concerning the fate of chloro-s-triazine herbicides, particularly atrazine, in the environment. It addresses the distribution of such herbicides and their metabolites in the soil and in water bodies, including the conditions that affect their transport mechanisms. The biodegradation pathways regarding the microbial degradation are presented as well as modification mechanisms of the compounds in plants capable of tolerating their action. Studies on the influence of the compounds on animal and human physiological processes and health, that is distribution of atrazine in the animal organisms, effects on the regulatory platform in the liver, possible carcinogenesis and endocrine disruption risks are assessed. Toxicity tests used for evaluation of the toxicity of the compounds are critically reviewed. Possible methods for atrazine degradation, including advanced oxidation procedures (AOP techniques), are outlined.

Toxicity in reaction mixtures of atrazine irradiated on immobilized TiO 2 at varying irradiation times was studied using an algal growth test on unicellular green alga Raphidocelis subcapitata and a cytotoxicity test with a RTgill-W1 cell line. The toxicity of atrazine samples to algae decreased exponentially with the time of irradiation on TiO 2 up to 3 h for both IC 50 and IC 20 values calculated for growth rate inhibition and yield. A trend to increasing variability between replicates in atrazine samples irradiated on TiO 2 for longer time periods was observed; the trend was particularly pronounced in samples irradiated for 3 and 5 hours, where the atrazine samples caused moderate stimulation in lower concentration treatments (up to 550 μg/l of the initial atrazine concentration). None of the atrazine samples showed significant cytotoxicity to the rainbow trout gill cell line (RTgill-W1).