Heavy metal accumulation and genotoxic effect of long-term wastewater irrigated peri-urban agricultural soils in semiarid climate

Mohamed Oubane; Ahmed Khadra; Amine Ezzariai; Lamfeddal Kouisni; Mohamed Hafidi

doi:10.1016/j.scitotenv.2021.148611

Heavy metal accumulation and genotoxic effect of long-term wastewater irrigated peri-urban agricultural soils in semiarid climate

Sci Total Environ. 2021 Nov 10:794:148611. doi: 10.1016/j.scitotenv.2021.148611. Epub 2021 Jun 22.

Authors

Mohamed Oubane¹, Ahmed Khadra¹, Amine Ezzariai², Lamfeddal Kouisni³, Mohamed Hafidi⁴

Affiliations

¹ Laboratory of Microbial Biotechnology, Agrosciences and Environment, Faculty of Science Semlalia, Cadi Ayyad University, Marrakesh 40000, Morocco.
² African Sustainable Agriculture Research Institute (ASARI), Mohammed VI Polytechnic University (UM6P), Laayoune 70000, Morocco.
³ African Sustainable Agriculture Research Institute (ASARI), Mohammed VI Polytechnic University (UM6P), Laayoune 70000, Morocco; University Mohammed VI Polytechnic (UM6P), Agrobiosciences Department, Benguerir, Morocco.
⁴ Laboratory of Microbial Biotechnology, Agrosciences and Environment, Faculty of Science Semlalia, Cadi Ayyad University, Marrakesh 40000, Morocco; University Mohammed VI Polytechnic (UM6P), Agrobiosciences Department, Benguerir, Morocco. Electronic address: hafidi@uca.ac.ma.

PMID: 34225150
DOI: 10.1016/j.scitotenv.2021.148611

Abstract

Water scarcity is becoming an alarming issue in the Mediterranean countries. Therefore, using the treated wastewater in the irrigation is considered as a valuable option. However, uncontrolled and long-term irrigation by wastewater leads to human health and environmental damages, mainly related to some specific pollutants. The assessment of the availability and toxicity of the heavy metals after long term irrigation, under semi-arid climate, is not yet well documented. In this study, physicochemical properties, genotoxicity (Vicia faba micronucleus test), total and available (CaCl₂-extractable) concentrations of Cr, Pb, Cu, Zn, Co and Cd in eight soils of peri-urban farms irrigated with wastewater were examined to evaluate their accumulation. The results indicated that long-term irrigation with wastewater induced significant increase of electrical conductivity, organic matter, calcium carbonate equivalent and nutrient availability. Total and available concentration of heavy metals were significantly higher (P < 0.05) in irrigated soils by wastewater. The total concentrations of Zn, Pb, Cu, Cr, Cd and Co in irrigated soils by wastewater at 0-40 cm depth were 85.69, 43.94, 34.86, 14.62, 9.94 and 7.17 mg kg^-1, respectively. Furthermore, the increase of the available metal fraction in irrigated soils by wastewater at 0-40 cm depth followed the following order: Co (1270.1%) > Cd (914.5%) > Cu (881.5%) > Cr (471.2%) > Pb (230.8%) > Zn (223.8%). The micronucleus assay indicated significant increase of micronucleus frequencies (41.25‰, 35.48‰, 21.66‰, 16.23‰ and 13.62‰ respectively for P1, P2, P3, P4 and P7) which were higher than the negative control (0‰) and the irrigated soil by fresh water (3.29‰). The micronucleus induction was significantly correlated with the high available fraction of Cd, Co and Zn at P1, P2 and P7. The genotoxicity can be a powerful test to assess the ecological effects associated with the interactions of heavy metals with other pollutants.

Keywords: Heavy metals; Long-term irrigation; Soil genotoxicity; Wastewater.

MeSH terms

Agricultural Irrigation
DNA Damage
Environmental Monitoring
Humans
Metals, Heavy* / analysis
Metals, Heavy* / toxicity
Soil
Soil Pollutants* / analysis
Soil Pollutants* / toxicity
Wastewater / analysis

Substances

Metals, Heavy
Soil
Soil Pollutants
Waste Water