Records of organochlorine pesticides in soils and sediments on the southwest of Buenos Aires Province, Argentina

Abstract

The present study fills a gap in the knowledge in regards to the occurrence of banned pesticides at both coastal and inland locations at the Southwest Buenos Aires region, Argentina. Superficial sediment and soil samples were collected from different sites along the Bahia Blanca Estuary and surrounding sites to assess the concentration levels and spatial distribution of 12 selected organochlorine pesticides (OCs); 13 spatial locations including inland and shore-coast were sampled to evaluate occurrence and concentration levels of hexachlorocyclohexanes α-HCH, β-HCH, δ-HCH, γ-HCH, dichlorodiphenyltrichloroethane and its degradation products (DDXs: p,p′-DDT, o,p′-DDT, p,p′-DDE, o,p′-DDE, p,p′-DDD, o,p′-DDD) and the polychlorobenzenes PeCB (pentachlorobenzene) and HCB (hexachlorobenzene). After cleaning and extractions steps, samples were analyzed by means of gas chromatography/mass spectrometry. ∑OCs (sum of all studied compounds) ranged between 0.206 and 1040 ng g−1 dw (mean = 82.4 and SD = 277 ng g−1 dw). Total HCHs (sum of α-HCH, β-HCH, γ-HCH and δ-HCH) ranged from 0.0858 to 0.876 ng g−1 dw (mean = 0.43 and SD = 0.23 ng g−1 dw), DDXs (sum of p,p′and o,p′ isomers) from 0.080 to 1040 ng g−1 dw (mean = 81.3 and SD = 277 ng g−1 dw). Lower concentrations were found for PeCB (mean = 0.095 and SD 0.17 ng g−1 dw) and HCB (mean = 0.56 and SD 1.7 ng g−1 dw). Principal component analysis (PCA) permitted the extraction of underlying information about common factors, providing an overview of the distribution of pesticides and allowing the characterization of sites in regards to the major pesticide signature.