Effects of Linear Alkylbenzene Sulfonate on Agricultural Soil and Its Degradation

Abstract

Contamination of soil and groundwater with toxic organic compounds is a widespread environmental problem. Surfactants are one of the pollutants that are produced in lot and widely used recently. Compared with other environmental pollutants, not much known about the behaviour and degradation of surfactants in soils. Linear alkylbenzene sulfonate (LAS) is the most used anionic surfactant and may enter the soil environment by irrigation wastewater or by amendment of the soil by sewage sludge. The aim of this study is to investigate degradation of LAS and its effects on chemical characteristics of soil. Field experiments were conducted on agricultural soil at Corlu Engineering Faculty. Commercial formulations of LAS were applied at four levels 2, 4, 6, 8 kg ha(-1) (L-1-L-4) and control. The experiment was organized as a trial design with divided parcels in randomized blocks with 3 factors. The soil samples were collected at four times 24, 48, 96 h and 30 days (T-1-T-4) after the application. The samples extracted for LAS residues and analysis of LAS was performed using MBAS method. Results showed that LAS concentrations ranged from 5.84 and 19.6 mg kg(-1). The differences reached important levels when compared to the control (p<0.01). The concentrations of LAS significantly decreased for period of time up to 30 days in the soil. The impacts of LAS on soil characteristics such as pH, electrical conductivity (EC), organic matter (OM) and cation exchange capacity (CEC) were statistically significant (p<0.05 and p<0.01).