Scovronick et al. 2025 — Human exposure to industrial toxicants in Glynn County, Georgia
This community-engaged biomonitoring study enrolled 100 adults in coastal Brunswick, Georgia, a city surrounded by four EPA National Priorities List Superfund sites contaminated with Aroclor 1268 PCBs, toxaphene pesticide, and mercury. The study was initiated at the request of local community leaders and environmental groups, and it measured whole blood metals (Pb, Cd, tHg) alongside serum PCBs, toxaphene, p,p’-DDE, and PFAS. The primary finding was that levels of the highly chlorinated PCBs associated with Aroclor 1268 were substantially elevated — 19–40% of participants exceeded the estimated 95th percentile reference levels for PCBs 196+203, 199, and 206 — while blood mercury levels were broadly comparable to the US general population. The seafood pathway emerged as a significant predictor of PCB exposure; participants who reported active fishing had significantly higher odds of detectable highly chlorinated PCBs (OR 5.25–8.52 for PCBs 199 and 206).
Key numbers
Metals (whole blood, ICP-MS, Agilent 7700; n = 96):
| Metal | Geometric Mean | GSD | NHANES 2017–2018 Reference GM | % above 95th percentile reference |
|---|---|---|---|---|
| tHg | Not individually tabulated; described as “comparable to US general population” | — | — | Not elevated |
| Pb | Not individually tabulated; described as comparable to US general population | — | — | Not elevated |
| Cd | Not individually tabulated; described as comparable to US general population | — | — | Not elevated |
Blood metals results were summarized as a group: participant levels of Pb, Cd, and tHg were similar to the general US population (NHANES 2017–2018 adults 20+). The paper did not report individual geometric means or standard deviations for the three metals separately in the main text tables; these are available in Table 2 of the published version.
Method LODs: tHg 0.139 ng/mL; Cd 0.518 ng/mL; Pb not separately stated but within the same 0.05–50 ng/mL calibration range. LOD/√2 imputation used for below-LOD values. Method precision (RSD) <10% for all metals.
Highly chlorinated PCBs (Aroclor 1268; n = 88 serum samples):
- PCB 206: study geometric mean approximately triple the estimated reference mean; 39.8% of participants above reference 95th percentile
- PCB 199: 25.0% above reference 95th percentile
- PCB 196+203: 19.3% above reference 95th percentile
Toxaphene (Parlars 26 and 50; n = 88): ~20% of participants above estimated 95th percentile reference (21.6% for Parlar 26, 20.5% for Parlar 50)
PFAS (n = 34): PFDA detected in 100% of participants; geometric mean twice the NHANES reference mean; 32.4% above reference 95th percentile.
Methods
Cross-sectional exposure study, March 2023. Whole blood collected by venipuncture into certified metal-free vacutainers. Metals analyzed by ICP-MS (Agilent 7700) with microwave digestion in ultra-purified nitric acid; internal standards rhodium, indium, lutetium, iridium; calibration range 0.05–50 ng/mL (Pb, Cd) and 0.05–2.5 ng/mL (Hg); reference materials NIST SRM 955c and RECIPE ClinChek controls within ±20% of certified values. PCBs, toxaphene, and p,p’-DDE analyzed by GC-MS/MS (Agilent) from serum. PFAS by online SPE-LC-MS/MS. Study population recruited by word-of-mouth and local media; prioritized residents near NPL sites, current fishers, and those with occupational exposure history.
Limitation: modest sample size (n = 96 for metals, n = 88 for organochlorines, n = 34 for PFAS). Self-reported dietary histories subject to recall bias. Reference values for PCBs and toxaphene derived from pre-2010 surveys with half-life adjustment; no validated reference values for toxaphene in the current US population.
Implications
Certification: tHg, Pb, and Cd blood levels in this Superfund-adjacent community were comparable to the US general population, indicating that local mercury and heavy metal contamination at these particular sites does not appear to have produced detectably elevated blood metal burdens beyond background US exposure levels. This finding constrains the relative contribution of local environmental sources versus background dietary (especially seafood) routes for mercury and other metals in a high-exposure-risk community.
Courses: Illustrates the seafood exposure pathway for persistent environmental contaminants (PCBs, toxaphene) in coastal communities; the distinction between legacy contamination traceable through bioaccumulation in local seafood versus current dietary exposure is pedagogically useful.
App: Direct relevance is limited; this is a biomonitoring study rather than a food-matrix concentration study. The paper does confirm that local seafood consumption is a significant predictor of PCB body burden in a contaminated coastal setting, which is consistent with the fish/shellfish contamination profile.
Microbiome: Not addressed in this paper.