Estimates of Tiber River organophosphate pesticide loads to the Tyrrhenian Sea and ecological risk

The organophosphate pesticides pollution in the Tiber River and its environmental impact on the Tyrrhenian Sea (Central Mediterranean Sea) were estimated. Eight selected organophosphate pesticides (diazinon, dimethoate, malathion, chlorpyrifos, pirimiphos-methyl, fenitrothion, methidathion, tolclofos-methyl) were determined in the water dissolved phase, suspended particulate matter and sediment samples collected from 21 sites in different seasons. Total organophosphate pesticides concentrations ranged from 0.40 to 224.48 ng L-1 in water (as the sum of the water dissolved phase and suspended particulate matter) and from 1.42 to 68.46 ng g(-1) in sediment samples. Contaminant discharges of organophosphate pesticides into the sea were calculated in about 545.36 kg year(-1) showing that this river should be consider as one of the main contribution sources of organophosphate pesticides to the Tyrrhenian Sea. In relation to the eco-toxicological assessment, the concentrations of most OPPs in the water and sediments from the Tiber River and its estuary were lower than guideline values.