Relationship between di-(2-ethylhexyl) phthalate concentration and chemical structure of organic matter on solids in drinking water treatment processes

Di-(2-ethylhexyl) phthalate (DEHP), regarded as a toxic substance, is widely used and abundantly contaminated in environments. Via contamination of freshwater, DEHP can enter into drinking water treatment and be adsorbed on solid particles. This study was aimed at understanding the concentration phenomenon of DEHP in drinking water treatment process, focusing on the relationship between DEHP concentration and characteristics of organic matter on the solids formed in the processes as scum, suspended solid and sludge. Solid samples were collected from five drinking water treatment processes in Japan and analyzed by pyrolysis GC/MS. The solids were categorized by the sampling locations, solid types and fragment composition. The specificity of the pyrolysis fragments in each group was summarized into a matrix. When compared with concentration of DEHP and characteristics of organic matter, a solid specifically containing many specific aliphatic fragments contained significantly high concentration of DEHP.