Determination of organochlorine pesticides in the surface water from Medjerda river, Tunisia

In recent years there have been growing environmental concern, especially regarding the utilisation and discharge of toxic substances. Many organic pollutants are detected in aquatic ecosystems such as pesticides. Because they are large-scale production and usage, toxicity, bioaccumulation, and persistence in the environment, they cause harmful effects to organisms and human health. The Medjerda River is one among the main rivers in Tunisia and a number of other studies addressed the importance of this river regarding ecology, geochemistry, and sociology. The organochlorine pesticides (OCPs) were investigated in surface water samples from eight sampling sites in the Medjerda River. The extraction of water samples was performed by liquid-liquid extraction with hexane. Gas chromatography coupled to the mass spectrum (GC-MS) was used to perform qualitative and quantitative determinations. The levels of OCPs in water varied between 4.41 ng g(-1) and 29.04 ng g(-1). The Hexachlorobenzene (HCB) and n-ary sumation DDT are the most dominant compounds in different sampling sites. Distribution of HCB, n-ary sumation DDT, and other OCPs are different indicating different sources of contamination. The concentrations of OCPs in the water pose no threat to human and aquatic living species.

Automated summary

In recent years, there has been increasing environmental concern about the utilization and discharge of toxic substances, specifically organic pollutants like pesticides, in aquatic ecosystems. These substances have harmful effects on organisms and human health due to their large-scale production and usage, toxicity, bioaccumulation, and persistence in the environment. The Medjerda River in Tunisia is one of the main rivers, and numerous studies have highlighted its ecological, geochemical, and sociological importance. This study investigated the presence of organochlorine pesticides (OCPs) in surface water samples from eight sampling sites in the Medjerda River, using liquid-liquid extraction with hexane and gas chromatography coupled to mass spectrometry for qualitative and quantitative determinations. The results showed varying levels of OCPs, with Hexachlorobenzene (HCB) and n-ary summation DDT being the most dominant compounds in different sampling sites, indicating different sources of contamination. However, the concentrations of OCPs in the water do not pose a threat to human or aquatic living species.