Study of the Impact of Copper on Soil Organisms and Tomato Quality

Background: The aim of our work is to assess the impact of copper-contaminated soil on tomato fruit and soil organisms. Excessive use of copper-based pesticides has many consequences for soil biology and food quality. Methods: Our study was carried out in a section of a tomato plot in the Mostaganem region of northern Algeria. The plot was contaminated with copper, at different doses D1 (10 mg Cu Kg-1), D2 (100 mg Cu Kg-1), D3 (200 mg Cu Kg-1) and D4 (300 mg Cu Kg-1) in separate blocks. The concentrations of copper and carbohydrates and the homogeneity of the wells were assessed in order to determine the quality of the tomatoes in relation to the levels of soil contamination. Furthermore, the respiratory activity of the microorganisms and the feeding activity of the soil fauna were assessed. Result: The highest copper concentrations were 1.5±0.17 mg Cu Kg-1 and 2.05±0.3 mg Cu Kg-1 in the sites contaminated by the highest doses D3 and D4 and the highest carbohydrate concentrations were 53.03±1.38 g kg-1 and 61.15±0.65 g kg-1 in these two sites. Microbial respiration values were lowest in D3, with 8.3.10-4 ± 3.6.10-4 mg CO2 g-1 h-1 and in D4, with 1.5.10-3 ±1.4.10-4 mg CO2 g-1 h-1. In addition, wildlife feeding activity was low at both sites, with values of 27.56±17.77 % for the D3 site and 37.5±17.48 % for the D4 site. Our study has shown that copper contamination of soils affects the biological activities of soil organisms.