Evaluation of the Transformation and Leaching Behavior of Two Polyfluoroalkyl Phosphate Diesters in a Field Lysimeter Study.

ABSTRACT

In this study, 62 and 82 polyfluoroalkyl phosphate diester (diPAP) were individually investigated in lysimeters under near-natural conditions. Leachate was sampled for 2 years, as was the soil after the experiment. In the leachate of the diPAP-spiked soils, perfluorocarboxylic acids (PFCAs) of different chain lengths were detected [23.2% (62 diPAP variant) and 20.8% (82 diPAP variant) of the initially applied molar amount]. After 2 years, the soils still contained 36-37% 62 diPAP and 41-45% 82 diPAP, respectively, in addition to smaller amounts of PFCAs (1.5 and 10.6%, respectively). Amounts of PFCAs found in the grass were low (<0.1% in both variants). The recovery rate of both 62 diPAP and 82 diPAP did not reach 100% (63.9 and 83.2%, respectively). The transformation of immobile diPAPs into persistent mobile PFCAs and their transport into the groundwater shows a pathway for human exposure to hazardous PFCAs through drinking water and irrigation of crops.