Sewage-Sludge Fertiliser on Garden Soil

Biosolids spread or sold as a soil conditioner or fertiliser.

41Moderate burden · out of 100

Cleaner swapA soil amendment whose feedstock is stated on the bag, or compost you make yourself

How this score is built

100Start
72.4Chemical hazard 6 × 4.6−27.6
62.2Everyday exposure 3 × 3.4−10.2
41Persistence 8 × 2.6−20.8, then rounded to 41
ModerateThe band41 sits in 40–59.

What each input rests on

The three ratings behind the score, and the studies each rests on
Input	Rating	Evidence
Chemical hazard	6/10	unsourced input
Everyday exposure	3/10	unsourced input
Persistence	8/10	In farm soils amended with typical municipal biosolids, PFOS was the dominant PFAS (2 to 483 ng/g of soil), soil levels rose linearly with cumulative biosolids loading, and traces were found down to 120 cm. Occurrence and fate of perfluorochemicals in soil following the land application of municipal biosolids · Environ Sci Technol 2011 DOI 10.1021/es103903d · PMID 21446724 · Abstract · read 2026-10-21

Ratings are editorial. A study listed here supports the rating; it did not compute it. How the index is built

What this means for you

The persistence rating is the standout concern here — these compounds linger in the body and environment for years. The EPA released a draft risk assessment on 14 January 2025 covering PFOA and PFOS in sewage sludge that is land-applied as a soil conditioner or fertiliser. It is a draft that went out for public comment, not a rule, so the useful response is knowing what an amendment is made from rather than treating any number as settled.

Evidence strength: moderate

Sources: US EPA, 'Draft Sewage Sludge Risk Assessment for Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonic Acid (PFOS)', released 14 Jan 2025, EPA 820-P-25-001, Docket EPA-HQ-OW-2024-0504

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Lower-exposure choices

Regular Sauna UseMinimal · Environment

Regular Exercise & SweatMinimal · Environment

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