Composting municipal food waste is a key strategy for beneficially reusing methane-producing waste that would otherwise occupy landfill space. However, land-applied compost can cycle per- and polyfluoroalkyl substances (PFAS) back into the food supply and the environment. We partnered with a pilot-scale windrow composting facility to investigate the sources and fate of 40 PFAS in food waste compost. A comparison of feedstock materials yielded concentrations of ∑PFAS under 1 ng g in mulch and food waste and at 1380 ng g in leachate from used compostable food contact materials. Concentrations of targeted ∑PFAS increased with compost maturity along the windrow (1.85–23.1 ng g) and in mature stockpiles of increasing curing age (12.6–84.3 ng g). Among 15 PFAS quantified in compost, short-chain perfluorocarboxylic acids (PFCAs) – C5 and C6 PFCAs in particular – led the increasing trend, suggesting biotransformation of precursor PFAS into these terminal PFAS through aerobic decomposition. Several precursor PFAS were also measured, including fluorotelomer carboxylic acids (FTCAs) and polyfluorinated phosphate diesters (PAPs). However, since most targeted analytical methods and proposed regulations prioritize terminal PFAS, testing fully matured compost would provide the most relevant snapshot of PFAS that could be land applied. In addition, removing co-disposed food contact materials from the FW feedstock onsite yielded only a 37 % reduction of PFAS loads in subsequent compost, likely due to PFAS leaching during co-disposal. Source-separation of food contact materials is currently the best management practice for meaningful reduction of PFAS in food waste composts intended for land application.

中文翻译：

---

研究食物垃圾堆肥中全氟烷基物质和多氟烷基物质 (PFAS) 的来源和归宿

对城市食物垃圾进行堆肥是有益地再利用产生甲烷的废物的一项关键策略，否则这些废物将占用垃圾填埋场空间。然而，土地施肥可以将全氟烷基物质和多氟烷基物质 (PFAS) 循环回食品供应和环境中。我们与一家中试规模的料堆堆肥设施合作，调查食物垃圾堆肥中 40 种 PFAS 的来源和去向。对原料进行比较后发现，覆盖物和食物垃圾中的 ΣPFAS 浓度低于 1 ng g，而使用过的可堆肥食品接触材料的渗滤液中的 ΣPFAS 浓度则为 1380 ng g。目标 ΣPFAS 的浓度随着堆肥成熟度的增加而增加（1.85–23.1 ng g），以及随着熟化年龄的增加（12.6–84.3 ng g）。在堆肥中量化的 15 种 PFAS 中，短链全氟羧酸 (PFCA)（尤其是 C5 和 C6 PFCA）引领了增加趋势，表明前体 PFAS 通过需氧分解生物转化为这些末端 PFAS。还测量了几种前体 PFAS，包括氟调聚物羧酸 (FTCA) 和多氟磷酸二酯 (PAP)。然而，由于大多数有针对性的分析方法和拟议法规优先考虑最终的 PFAS，因此测试完全成熟的堆肥将提供可用于土地应用的 PFAS 的最相关快照。此外，现场从 FW 原料中去除共同处置的食品接触材料仅使后续堆肥中的 PFAS 含量减少了 37%，这可能是由于共同处置过程中 PFAS 的浸出所致。食品接触材料的源头分离是目前有效减少用于土地应用的食物垃圾堆肥中 PFAS 的最佳管理实践。