Environmental Forensic Investigation of PFAS in Biosolids Land Application, Wastewater Source Tracing, and Agricultural Soil and Groundwater Impacts
Project Overview
RoseyFields conducted an environmental forensic investigation involving per- and polyfluoroalkyl substances (“PFAS”) associated with municipal biosolids land application and the resulting potential contamination of agricultural soils, groundwater, surface water, and drinking-water supplies. The investigation focused on the movement of PFAS from industrial and commercial users into publicly owned treatment works (“POTWs”), the partitioning of those compounds into wastewater solids and biosolids, and the subsequent land application of those biosolids onto farms and other permitted sites. The work integrated biosolids regulatory review, wastewater residuals management research, state PFAS monitoring datasets, source-identification concepts, and land-application records to evaluate whether biosolids recycling practices created a plausible pathway for PFAS migration to impacted properties and water resources.
The case was framed around a recurring forensic question in PFAS litigation and environmental assessment: whether land-applied biosolids can serve as a transport medium that transfers PFAS from upstream industrial dischargers to agricultural landowners, dairy operations, food-crop farms, and rural residents who rely on private wells. RoseyFields evaluated this question through a multi-state lens, with particular attention to Maine and Georgia, where biosolids management practices, public data availability, and regulatory structures create different but complementary evidence streams. The project examined not only biosolids themselves, but also the broader wastewater residuals system that can include POTW influent, effluent, sludge, composted biosolids, septage, and in some cases landfill leachate and mixed residual streams.
The investigation also addressed the major technical challenge in biosolids PFAS cases: source tracing. PFAS in land-applied biosolids do not arise from one universal source. Instead, they may originate from multiple industrial users discharging to a POTW, including sectors historically associated with PFAS use such as paper mills, chrome plating, textile and carpet manufacturing, leather treatment, aqueous film-forming foam (“AFFF”) contamination sources, and landfill leachate management. RoseyFields evaluated how those upstream source categories can be obscured by municipal treatment systems, third-party composting operations, mixed residual handling, and incomplete state datasets, while still leaving measurable evidence in biosolids, soils, groundwater, and other environmental media.
A central objective of the case was to determine whether available regulatory records, monitoring data, and site-specific application information were sufficient to reconstruct a scientifically defensible source-to-receptor pathway for PFAS contamination associated with biosolids land application. To answer that question, RoseyFields reviewed federal biosolids regulations, state sewage-sludge permitting frameworks, biosolids annual reporting requirements, statewide PFAS monitoring initiatives, Maine PFAS site data, and state survey information regarding biosolids oversight, monitoring, and source-assessment practices. This allowed the case to be evaluated as both a contaminant fate-and-transport problem and a regulatory forensic reconstruction problem.
Chemicals of Concern
The chemicals of concern in this case were per- and polyfluoroalkyl substances (PFAS) present in wastewater, sludge, biosolids, soils, groundwater, surface water, and in some cases agricultural products or livestock exposure pathways. PFAS are a large class of highly persistent fluorinated organic compounds characterized by strong carbon–fluorine bonds, environmental persistence, mobility, and resistance to conventional wastewater treatment processes. In the biosolids context, PFAS are important because many compounds partition into wastewater solids during treatment, which can concentrate them in sludge and biosolids that are subsequently land applied. Once biosolids are spread on agricultural fields, PFAS may remain in soil, leach vertically to groundwater, move laterally in runoff or shallow subsurface flow, and potentially enter crops, livestock forage, or private wells.
The investigation gave particular attention to the PFAS analytes most commonly identified in state biosolids and environmental monitoring programs, including PFOA, PFOS, PFNA, PFDA, PFHxS, and PFHpA, as well as a broader suite of PFAS compounds reflected in Maine’s analytical datasets. Maine’s biosolids-related regulatory response specifically references a 20 ppt drinking-water threshold for the sum of six PFAS chemicals—PFOA, PFOS, PFNA, PFDA, PFHxS, and PFHpA—illustrating the importance of mixture-based exposure metrics rather than reliance on a single analyte.
The case also recognized that PFAS occurrence in biosolids is not limited to a single source chemistry or industrial sector. State survey materials reviewed by RoseyFields identified chrome platers, AFFF-impacted facilities, leather tanneries, landfills, and paper mills as examples of industries associated with PFAS loading to treatment plants in some state source-assessment programs. That observation is important because biosolids PFAS cases often require a mixed-source exposure framework in which multiple industrial contributors may discharge distinct PFAS fingerprints to a common POTW, and the resulting biosolids may then be applied across multiple agricultural or rural sites.
In addition to biosolids and soil contamination, the relevant exposure media in this case included groundwater, residential well water, surface water, and potentially crops or forage. The Maine PFAS data compilation and related SWAPE materials reflect a multimedia investigation framework in which sludge-application sites are evaluated not only for biosolids chemistry, but also for PFAS concentrations in soils, groundwater, wastewater, fish, sediment, and other environmental media. That multi-compartment approach is consistent with the environmental behavior of PFAS, which can move across media over long timeframes and create exposure pathways long after the original land application event.
Methods
RoseyFields applied a multidisciplinary environmental forensic methodology to evaluate PFAS contamination associated with biosolids land application. The work combined regulatory analysis, source-tracing review, land-application record review, environmental monitoring dataset review, and state-specific biosolids program evaluation. The objective was to determine whether publicly available and case-specific data could be used to connect upstream PFAS sources to POTWs, biosolids generation, land application sites, and ultimately impacted farms or rural properties.
RoseyFields first reviewed the biosolids management framework governing land application at the federal and state levels. The project materials note that federal biosolids regulations under 40 CFR Part 503 divide biosolids into Class Aand Class B categories based primarily on pathogen reduction requirements and allow land application to food crops and other land uses subject to restrictions, but do not currently establish federal PFAS-specific limits or guidance for PFAS-contaminated biosolids. This regulatory gap is a central technical issue in the case because it means that historical biosolids land application could proceed under pathogen-, metal-, nutrient-, and vector-attraction-based requirements without any federal contaminant thresholds specific to PFAS.
The state regulatory review then examined how biosolids permitting and reporting systems operate in specific jurisdictions. In Georgia, the state biosolids rule establishes requirements for beneficial land application of sewage sludge, including pollutant limits, pathogen reduction, vector-attraction reduction, operational standards, monitoring, reporting, and permitting requirements. The Georgia rule also defines “agricultural land,” “agronomic rate,” annual pollutant loading rate, and annual sludge application rate, all of which are relevant to reconstructing where and how biosolids were land applied. The Georgia biosolids annual report form further requires facilities to report dry tons of biosolids generated, land applied, landfilled, incinerated, transported, or composted, together with acreage, crop information, and land-application site documentation. Those records are potentially valuable in a PFAS case because they can be used to identify generators, application volumes, permitted acreage, and crop uses even where PFAS were not historically monitored.
RoseyFields then evaluated state-specific datasets and research materials to determine how much site-specific environmental evidence exists at biosolids land application sites. Maine was a major focus because the state has developed a substantial public record of PFAS investigation related to sludge and septage application. The SWAPE biosolids PFAS presentation notes that Maine has conducted testing of POTWs for PFAS, sampled licensed sludge-application sites, and developed a public statewide mapping system showing licensed sludge and septage sites with soil and water sampling locations. The materials further indicate that sampling was prioritized in areas where large sludge volumes were applied and where homes were located nearby, and that the database contains information on PFAS levels, application dates, land ownership and usage, and at least limited information regarding facilities responsible for the sludge.
The Maine PFAS data compilation was also reviewed as a technical dataset reflecting the types of analytes, sample media, qualifiers, and reporting structure available for statewide PFAS investigation. The data compilation includes multiple sample types—such as drinking water, groundwater, surface water, soil, sludge, wastewater, leachate, compost, manure, and vegetation—and documents concentrations for a wide suite of PFAS compounds, together with reporting limits and treatment-status fields. From a forensic standpoint, that kind of statewide database is useful because it allows analysts to evaluate whether contamination patterns are concentrated at biosolids sites, whether impacts appear in downgradient groundwater or residential wells, and whether particular sites exhibit PFAS profiles consistent with specific source categories or repeated land application.
A third major component of the methodology was evaluation of PFAS source tracing within wastewater treatment systems. The SWAPE presentation expressly identified the goal of determining which industries discharged PFAS-contaminated wastewater to POTWs whose biosolids were later land applied, with emphasis on industries such as carpet manufacturers, paper mills, and chrome platers, and on landowners such as dairies, food-crop growers, and other agricultural operations that may have potential damages. RoseyFields reviewed that source-tracing framework together with ECOS state survey findings indicating that some states have conducted industry-specific or source-assessment-based monitoring and reporting, while also recognizing that source tracing is often difficult because many POTWs receive wastewater from numerous industrial and non-industrial contributors.
The methodology also explicitly accounted for the limitations of source tracing. The SWAPE materials identify several recurring obstacles: third-party composters or residual handlers may combine residuals from multiple wastewater facilities; large POTWs may have many industrial users; PFAS may also enter wastewater systems from landfill leachate, residential sources, and other non-industrial pathways; and soil or well sampling at private landowner properties may be limited. Those limitations are highly relevant in litigation or site assessment because they mean that a complete source-to-site reconstruction may require integrating permit files, pretreatment records, industrial user lists, annual biosolids reports, haul records, land-application permits, and environmental sampling results rather than relying on any one dataset.
RoseyFields also used a comparative state-policy framework to evaluate how biosolids PFAS management has evolved nationally and to identify what kinds of evidence may be available in a given jurisdiction. The ECOS-based state survey materials reviewed in the case show that state responses are highly variable: some states require PFAS sampling in biosolids, some conduct system-wide monitoring, some require source assessment and reporting, some have undertaken multi-media monitoring at or downstream of land-application sites, and some make monitoring data publicly available. Maine stands out because it has moved from monitoring and site investigation to a statutory ban on land application of biosolids-based soil amendments, while Georgia appears in the survey as one of the states that has conducted multimedia monitoring in soil, groundwater, or surface water at or downstream from biosolids land-application sites.
Results
The investigation demonstrated that biosolids land application is a technically plausible and, in some states, well-documented pathway for PFAS migration from municipal wastewater systems to agricultural land and rural drinking-water receptors. The key forensic mechanism is straightforward: upstream industrial and commercial PFAS discharges enter POTWs; treatment processes partition at least part of that PFAS burden into wastewater solids; those solids are managed as biosolids or related residuals; and land application places the PFAS mass directly onto soils where it may persist, accumulate, and migrate to groundwater, crops, or surface waters over time. What makes the case complex is not the conceptual pathway, but rather the evidentiary challenge of reconstructing the responsible contributors and the specific land-application footprint years after the fact.
A major result of the project was the recognition that federal biosolids regulation does not currently provide a PFAS-specific management framework, leaving a patchwork of state responses. The materials reviewed by RoseyFields state that there are currently no federal regulations or guidance for PFAS-contaminated biosolids under the land-application regime, while state programs vary widely in whether they require PFAS sampling, source assessment, or site monitoring. This absence of uniform federal standards increases the importance of state records, state monitoring programs, and site-specific environmental data in forensic investigations of biosolids-related PFAS contamination.
The state-comparison review also showed that Maine represents one of the strongest examples of a developed evidentiary record for biosolids PFAS impacts. Maine has both statewide PFAS environmental data and a regulatory response that directly targets biosolids land application. The SWAPE materials note that Maine DEP sampled soil and groundwater at licensed biosolids sites, tested wastewater treatment plant effluent statewide, and made site information publicly available through a statewide mapping system. Maine also enacted LD 1911, which bans the land application, sale, and distribution of biosolids-based soil amendments and restricts septage land application where nearby groundwater exceeds the state’s interim PFAS drinking-water threshold of 20 ppt for the sum of six PFAS chemicals.
The Maine-specific materials further show that land-application site contamination can be substantial and measurable in soil. In the SWAPE presentation summarizing Maine results, the top five sludge-application sites with the highest soil concentrations of PFOA and PFOS included values of approximately 707.4 ppb, 519.1 ppb, 462.4 ppb, 363.4 ppb, and 322.9 ppb at sites associated with agricultural or forestry land uses. These sites included hay, potato, oat, corn, pasture, forest, and manure-pit-associated application areas, illustrating that PFAS contamination associated with biosolids application is not confined to one crop type or one agricultural setting.
The investigation also found that Georgia has a meaningful biosolids regulatory and recordkeeping framework that could support future PFAS forensic reconstruction even if the state historically lacked PFAS-specific biosolids limits. Georgia’s sewage sludge rule requires land-application permitting, sludge management planning, soil and sludge analyses, site-use information, crop and grazing information, transport information, and annual reporting of biosolids generation and land application. Those records, combined with EPD district and watershed contacts, could be used to identify land-application sites, generator facilities, acreage, crop uses, and potentially the wastewater treatment works and land-application systems associated with a contaminated site. In a PFAS case, that information is particularly useful because it helps bridge the gap between environmental contamination observed on a farm and the biosolids generator or applicator responsible for the application event.
Another important result was the recognition that source tracing to specific PFAS contributors is often the most difficult part of the case. RoseyFields’ review confirmed that POTWs frequently receive wastewater from multiple industrial and non-industrial contributors, that third-party composters may mix residuals from multiple facilities, and that landfill leachate and residential sources may also contribute PFAS to treatment systems. The state survey materials likewise note that states such as Massachusetts have found it difficult to perform industry-specific testing where several industries discharge to a single POTW, even though in theory PFAS in sludge could eventually be linked to industrial user types. This means that a strong biosolids PFAS case often depends on combining multiple lines of evidence—industrial pretreatment records, POTW influent/effluent monitoring, biosolids testing, annual reports, land-application records, and environmental sampling—rather than expecting a single document to establish causation.
Finally, the comparative state review showed that biosolids PFAS investigations are increasingly multimedia rather than sludge-only investigations. The ECOS survey materials indicate that at least twelve states, including Georgia and Maine, have conducted monitoring in soil, groundwater, or surface water at or downstream from biosolids land-application sites. This trend is significant because it reflects a shift away from viewing biosolids as a discrete solid-waste issue and toward evaluating them as a cross-media contaminant transport problem affecting soils, aquifers, streams, crops, and potentially livestock operations. That cross-media perspective is essential in agricultural PFAS cases, where the primary damages may involve not only soil contamination but also loss of potable water, reduced agricultural value, impaired crop or forage use, and long-term land management constraints.
Conclusions
This environmental forensic investigation demonstrates that biosolids land application is a scientifically credible pathway for PFAS contamination of agricultural soils, groundwater, and rural drinking-water supplies, particularly where upstream industrial PFAS sources discharge to municipal wastewater treatment systems and the resulting residual solids are beneficially reused on land. The project showed that the key technical questions in these cases are not limited to whether PFAS are present in biosolids; rather, they involve reconstructing the entire chain of contaminant transport from industrial user to POTW, from POTW to sludge or biosolids, from biosolids to land-application site, and from land-applied soil to downgradient receptors such as wells, crops, livestock forage, and surface waters.
A principal conclusion of the investigation is that state-specific data availability strongly controls the strength of a biosolids PFAS case. Maine currently provides one of the clearest examples of a state where publicly available site-level PFAS sampling, biosolids site mapping, and regulatory action can be integrated into a robust source-to-site contamination narrative. By contrast, states with traditional biosolids reporting and permitting systems—but limited PFAS-specific monitoring—may still support a strong forensic investigation, but only if annual biosolids reports, permit files, POTW records, pretreatment data, and land-application documentation can be assembled and cross-referenced. In other words, the scientific problem is often solvable, but the data assembly burden can be substantial.
The case also underscores that PFAS biosolids matters are fundamentally multimedia contamination cases. The relevant evidence extends beyond sludge chemistry to include soil concentrations, groundwater impacts, residential well contamination, surface-water transport, land-use information, crop types, and in some cases livestock exposure pathways. For that reason, RoseyFields’ work in this area necessarily integrates environmental chemistry, hydrogeology, agricultural land-use reconstruction, wastewater residuals management, source-tracing analysis, and regulatory forensic review rather than relying on a narrow single-medium investigation.
Another important conclusion is that the absence of federal PFAS-specific biosolids standards does not eliminate the forensic significance of biosolids contamination. To the contrary, the regulatory gap heightens the need for retrospective technical evaluation of historical land-application practices, particularly in states where biosolids were widely applied to farms before PFAS monitoring became common. The evidence reviewed here shows that states are increasingly moving toward sampling, source assessment, and land-application restrictions, and that at least some states have already documented significant PFAS contamination at biosolids sites. That trend supports the view that historical biosolids management practices may represent a major and underappreciated PFAS exposure pathway in agricultural communities.
This case study highlights RoseyFields’ work at the intersection of PFAS chemistry, biosolids management, wastewater source tracing, agricultural contamination assessment, groundwater pathway analysis, and environmental forensic causation analysis. The investigation required synthesis of sewage-sludge regulations, POTW residuals management practices, annual land-application reporting, statewide PFAS datasets, agricultural site information, and cross-media sampling results to evaluate whether land-applied biosolids created foreseeable contamination of private property and water resources. These are the kinds of technical investigations RoseyFields performs in matters involving PFAS, wastewater residuals, drinking-water contamination, agricultural impacts, and long-term contaminant fate and transport.
This investigation was conducted under the direction of Dr. Paul Rosenfeld, an environmental scientist and environmental forensic expert with experience in PFAS contamination assessment, wastewater and biosolids source evaluation, groundwater and soil contamination analysis, exposure reconstruction, regulatory review, and technical causation analysis. Through RoseyFields LLC, Dr. Rosenfeld provides environmental forensic analysis, contaminant fate-and-transport evaluation, source tracing, risk and exposure assessment support, regulatory review, and expert witness services in matters involving PFAS, industrial discharges, land application, and agricultural contamination.
References
Environmental Council of the States. (2023, January). PFAS in biosolids: A review of state efforts & opportunities for action. ECOS.
Georgia Department of Natural Resources, Environmental Protection Division. (2009). Biosolids annual report [form].
Georgia Department of Natural Resources, Environmental Protection Division. (2022). EPD program directory (Rev. Feb. 2022). Useful for identifying Watershed Protection Branch and biosolids program contacts.
Georgia Department of Natural Resources, Environmental Protection Division. (2024). Georgia sewage sludge (biosolids) requirements, Rule 391-3-6-.17. Georgia Administrative Code.
Maine Department of Environmental Protection. (2020). Maine PFAS data (2007–2020) / EGAD database extract.
Maine Department of Environmental Protection. PFAS investigation map and site data (as summarized in SWAPE presentation materials). Referenced in project materials for statewide sludge-site soil and groundwater investigation results.
National Biosolids Data Project. (2021, September). Maine biosolids. Referenced in SWAPE materials regarding biosolids use, land application, and state restrictions.
RoseyFields / Soil Water Air Protection Enterprise. (2024, September 13). Evaluation of biosolids land application sites, PFAS sources and impacted parties [technical presentation / draft project materials].
U.S. Environmental Protection Agency. 40 CFR Part 503 – Standards for the use or disposal of sewage sludge.Referenced in project materials as the federal biosolids management framework lacking PFAS-specific standards.