Plant Ecotoxicology : Course handouts Course: phytotoxicity and toxic substances effects L3 plant biotechnology

Abstract

The importance of studying the ecotoxicity of plants lies in protecting humans and animals that feed on them and raising awareness that their release into the environment follows the water cycle. Toxicity, therefore, is transmitted to us through inhalation of polluted air, consumption of contaminated water, or poisoned food from various sources. It is also crucial to recognize the disappearance of certain plant and animal species and the imbalances in several food chains caused by the accumulation of different pollutants in the same environment. Natural climatic phenomena, to the same degree as anthropogenic stressors, affect species biodiversity and ecosystem balance. In polluted environments, organisms are exposed to a complex mixture of contaminants. This exposure sometimes causes toxic effects even if the pollutants are present individually and at concentrations much lower than the concentration determined without observable effects (Brian et al. , 2007). This phenomenon is defined as a combined effect, a mixed toxicity or cocktail effect. Chemical toxicity assessment is normally carried out substance by substance, neglecting the possibility of a combined effect. It is possible to underestimate the combined effects of contaminants with similar effects or different modes of action that interact and change the toxic effect of the two toxic substances tested separately. These combinations give rise to countless possibilities of additive, synergistic, or antagonistic combinations (Figure I.1.a).