Bai et al. 2022 — Arsenic contamination from coal burning in Shaanxi, China, with food and biomarker data
This cross-sectional study investigates arsenic (As) exposure in a coal-burning area of Shaanxi Province, China, where endemic arseniasis (arsenicosis) has been documented from indoor coal combustion used for drying food. The study reports As concentrations in food (corn and peppers), coal, soil, water, and human biomarkers (urine, blood, hair) from 100 arseniasis patients and 50 healthy controls. Coal and food arsenic levels grossly exceeded Chinese national standards, establishing a direct food-matrix contamination pathway from coal combustion.
Key numbers
- Food As concentrations (dry weight basis):
- Corn: 4.24 ± 6.77 mg/kg (mean ± SD); Chinese standard GB2762-2005 limit for coarse cereals is 0.2 mg/kg — mean exceeds limit 21-fold
- Pepper: 12.80 ± 23.70 mg/kg; GB2762-2005 limit for vegetables is 0.05 mg/kg — mean exceeds limit 256-fold
- Coal As: mean 1,620 mg/kg; far above background coal levels
- Soil As: elevated in study area relative to Shaanxi background
- Human biomarkers: urine As, blood As, and hair As all significantly elevated in arseniasis patients vs controls (p<0.05 for all); exact values in paper figures
- Selenium levels in soil and food were simultaneously low in the study area (Se deficiency documented), relevant to toxicokinetic interaction with As
- Study area: Ziyang county, Shaanxi Province, China; arseniasis from indoor coal burning for food drying is the primary exposure route
- n=150 (100 patients, 50 controls); case-control design
Methods (brief)
Atomic fluorescence spectrometry (AFS) for total arsenic in food, coal, soil, and water samples. Urine, blood, and hair collected and analyzed for total As. Case-control design with 100 arseniasis patients (clinically diagnosed by national standard GB/T 17222-2014) and 50 age-sex-matched healthy controls from the same geographic area. Food samples collected from participant households. Statistical analysis by SPSS; Spearman correlation used for dose-response assessment.
Implications
Certification: Food contamination from coal burning is a supply-chain pathway relevant to spices and cereals from coal-burning regions of Asia; not typically addressed in HMT&C certification for imported food, but contextualizes why country-of-origin matters for corn and pepper sourcing from western China. Courses: Strong case study for non-agricultural arsenic contamination routes in food (coal-drying pathway); illustrates why total arsenic in food from certain regions can vastly exceed regulatory limits set for pesticide/soil pathways. App: Corn and pepper arsenic concentrations from this study are extreme outliers specific to coal-burning exposure; not representative of general commerce and should not be used for app baseline estimates. Flag as special-context data. Microbiome: Not addressed.