Bioremediation of Agricultural Soils Polluted with Pesticides: a review

2021
, 
8
, x FOR PEER REVIEW 
11 of 29 
Table 6. 
Classification of the most common fungicides used in agricultural soil. 
Name 
Pesticide Class 
Chemical Structure 
Mode of Action 
Mancozeb Carbamate 
Inhibition of enzyme activity in fungi by 
forming a complex with metal-containing en-
zymes. 
Chlorothalonil Organochloride 
Reductor and deactivator of glutathione. 
Captan Organochloride 
Reduction of enzymatic activity. 
Maneb Carbamate 
Reaction and inactivation of sulfhydryl 
groups of amino acids and enzymes, causing 
damage to lipid metabolism, respiration, and 
production of adenosine triphosphate. 
Ziram Carbamate 
Creation of chemical barrier between the 
plant and a fungus. 
Tebuconazole Organochloride 
Inhibitor of sterol 14
α
-demethylase 
3. Diffusion of Pesticides into the Environment and Their Toxicology 
Pesticides aim to prevent, remove, and control harmful pests, but they may be harm-
ful to the environment and human health. Their excessive use can give high concentra-
tions of polluting substances in the environment. In the years, the World Health Organi-
zation ranked the pesticides and reported their toxicity and their effects on human health 
[54]. 
Through time, several pesticides have been banned in some countries due to their 
high toxicity. However, at the moment, their production and use go on, especially in de-
veloping countries. 
3.1. Presence and Distribution into the Environment 
The pesticides persist in the environment and may bioaccumulate and contaminate 
the food chain, affecting human health and the environment as a whole. Pesticide tends 
to conserve its molecular integrity and chemical, physical, and functional characteristics 
for a certain time after being released into the soil [55]. 
The parameter that can be considered to evaluate its persistence into the soil is the 
half-time (t
1/2
), that is, the time required for a compound to halve its initial concentration. 
Pesticides with short half-times accumulate and persist less into the soil. By contrast, 
pesticides with long half-times are more persistent and this may increase the risk to con-
taminate the environment. 
Altogether, they can be classified as [56]: 
Reduction of enzymatic activity.
Maneb
Carbamate
Bioengineering