BIOREMEDIATION OF HERBICIDE-CONTAMINATED SOILS

Abstract

Contamination of soils, groundwater, and surface water with herbicides poses significant cleanup challenges. Currently, the most common approach is containment, which involves expensive disposal of heavily contaminated soils to landfills. Bioremediation methods for in-situ treatment are needed as alternative and/or complementary approaches for cost-effective, waste-free cleanup. Microbes can be used to remediate herbicide-contaminated soil through a process called bioremediation, in which microorganisms degrade or convert contaminants into less harmful ones. This process can occur naturally or be enhanced by adding certain microorganisms or nutrients to the soil. Microorganisms such as bacteria and fungi have enzymes that can break down herbicides into less toxic compounds. They often use these herbicides as a food source. Remediation can be done in situ or by removing the soil for treatment (ex situ). Microbial remediation is influenced by the following factors: microbial activity (the type and number of microorganisms present and their ability to degrade a particular herbicide); environmental conditions (factors such as temperature, humidity, pH, and nutrient availability can affect the growth and activity of microorganisms); herbicide properties (the chemical structure and concentration of the herbicide can affect its biodegradability); soil properties (soil type, organic matter content, and aeration can affect microbial activity and the bioavailability of the herbicide).