Phthalate contamination in agricultural and non-agricultural soils around landfills in Guilan Province, Iran

There are growing concerns about the negative effects of soil pollution caused by improper waste disposal and leachate generation. The favorable climate and rich soils have made Gilan province one of the main agricultural centers of Iran. Phthalates (PAEs) are among the common lubricants that may pose a widespread risk to the environment due to their difficulty in degradation. This study investigated the environmental impacts of PAEs at 26 locations in 5 cities in the west and center of Gilan province. For this purpose, 4 to 7 mixed soil samples were collected from agricultural and non-agricultural lands, located 100 to 700 meters from each landfill. Soil physicochemical parameters and PAEs concentrations were measured. The concentrations of PAEs were measured using a standard extraction method (EPA Method 8061 A) by a gas chromatography-mass spectrometry (GC-MS) instrument. The results showed that the concentrations of PAEs in agricultural and non-agricultural soils were significantly different (<i>p</i> < 0.05). The highest concentration was BEHP with 59.6% (14.37 ppb in agricultural soils and 50.61 ppb in non-agricultural soils). Other PAEs identified included DOP (26.99%), DMP (11.48%), IBP (1.69%), DEP (0.09%), BBP (0.14%) and DBP (0.1%). The risk assessment results show that the levels of PAEs, especially BEHP and DNOP, are significantly higher than the MRL, TDI, and RfD standards. This study emphasizes the need for proper waste management and continuous monitoring of soil quality to prevent the negative effects of these pollutants on the environment.<i>Implications</i>: This study addresses soil pollution caused by imroper waste and leachate disposal in Gilan province, a key agricultural region in Iran. By analyzing the concentrations of phthalates (PAEs) in soils, we provide important information about the extent of pollution in agricultural and non-agricultural lands. Our findings indicate significant differences in the distribution of PAEs, especially higher concentrations in non-agricultural soils, and key PAE compounds. These results are essential for environmental managers and policymakers to develop effective strategies for soil protection and pollution reduction in Gilan and similar regions.