Polyfluoroalkyl phosphate esters (PAPs) are high production volume surfactants used in the food contact paper and packaging industries. They are prone to partition to soil due to their strong hydrophobicity and may biotransform into recalcitrant perfluoroalkyl carboxylic acids (PFCAs); little is known about their fate and behaviors in terrestrial organisms. Here, geophagous earthworms (M. guillelmi) were exposed to 6:2 fluorotelomer phosphate diester (6:2 diPAP)-contaminated soil to examine tissue-specific accumulation and biotransformation. 6:2 diPAP quickly accumulated in M. guillelmi with the highest biota-soil-accumulation factor (BSAF) in the gut, followed by the organs, skin, and body fluid. The total amount of 6:2 diPAP accumulated in the skin was the highest due to its high mass content. These results indicated that skin absorption and gut processes were two major pathways for earthworms to accumulate 6:2 diPAP from soil. In vitro desorption experiments indicated that the gut digestion fluid greatly promoted the desorption of 6:2 diPAP from the soil and enhanced its bioavailability. Degradation of 6:2 diPAP in the soil was stimulated when the earthworm appeared. In contrast to the soil, a more extensive transformation occurred in the earthworm. Perfluorohexanoic acid (PFHxA) was the primary phase Ⅰ product, followed by perfluoropentyl propanoic acid (FPePA), perfluoropentanoic acid (PFPeA), 2-perfluorohexyl ethanoic acid (FHEA), and perfluoroheptanoic acid (PFHpA), which confirmed the occurrence of α- and β-oxidation in earthworms. For the first time, a new phase II product, namely, a 6:2 fluorotelomer alcohol sulfate conjugate, was identified in earthworms at unexpectedly high levels, which might be the primary way earthworms eliminate 6:2 diPAP. Both in vivo and in vitro experiments suggested that 6:2 diPAP experienced faster and more extensive biotransformation in the gut than in the organs. This work sheds light on the bioaccumulation and biotransformation of 6:2 diPAP in terrestrial invertebrates, providing strong evidence of indirect sources of PFCAs in the environment.

多氟烷基磷酸酯 (PAP) 是用于食品接触纸和包装行业的高产量表面活性剂。由于它们的强疏水性，它们很容易分配到土壤中，并且可能会生物转化为顽固的全氟烷基羧酸 (PFCA)；人们对它们在陆地生物中的命运和行为知之甚少。在这里，将食地蚯蚓 ( M. guillelmi ) 暴露在 6:2 含氟调聚物磷酸二酯 (6:2 diPAP) 污染的土壤中，以检查组织特异性积累和生物转化。6:2 diPAP 在M. guillelmi中迅速积累在肠道中具有最高的生物-土壤累积因子 (BSAF)，其次是器官、皮肤和体液。由于质量含量高，皮肤中积累的 6:2 diPAP 总量最高。这些结果表明，皮肤吸收和肠道过程是蚯蚓从土壤中积累 6:2 diPAP 的两个主要途径。体外解吸实验表明，肠道消化液极大地促进了 6:2 diPAP 从土壤中解吸并提高了其生物利用度。当蚯蚓出现时，刺激了土壤中 6:2 diPAP 的降解。与土壤相比，蚯蚓发生了更广泛的转变。全氟己酸（PFHxA）为Ⅰ相初级产物，其次是全氟戊基丙酸（FPePA）、全氟戊酸（PFPeA）、2-全氟己基乙酸（FHEA）和全氟庚酸（PFHpA），证实了α-和蚯蚓的β-氧化。首次在蚯蚓体内发现了一种新的 II 期产品，即 6:2 含氟调聚物醇硫酸盐偶联物，其含量出乎意料地高，这可能是蚯蚓消除 6:2 diPAP 的主要方式。两个都体内和体外实验表明，6:2 diPAP 在肠道中比在器官中经历了更快和更广泛的生物转化。这项工作揭示了 6:2 diPAP 在陆生无脊椎动物中的生物积累和生物转化，为环境中 PFCA 的间接来源提供了强有力的证据。