Qu et al. 2022 — Pb/Cd co-exposure via drinking water and soil, southern China
This cross-sectional study measured Pb and Cd concentrations in drinking water and soil at 15 sites in two communities in Guangdong Province (southern China) and estimated average daily dose (ADD) exposures for 1,274 adult residents aged ≥40. Concentrations were measured by ICP-MS at the Public Monitoring Center for Agro-product, Guangdong Academy of Agricultural Sciences. The study then examined whether estimated Pb/Cd exposures were associated with type 2 diabetes mellitus (T2DM) and obesity indices (BMI, waist-hip ratio, waist circumference). The Dapeng/Hengqin communities are in the Pearl River Delta, a region with documented e-waste processing and associated heavy metal contamination.
The primary measurement findings are that Pb and Cd pollution in local drinking water and soil was described as “serious” relative to Chinese safety standards. The health outcome analysis found no statistically significant association between ADD of Pb or Cd and T2DM (all p > 0.05). However, higher Pb ADD was inversely associated with overweight/obesity indices (1 µg/kg bw/day ADD of Pb associated with 49–56% lower likelihood of overweight, and WHR decreasing by 0.01–0.02, and WC decreasing by 2.22–4.67 cm). 1 µg/kg bw/day ADD of Cd was associated with higher likelihood of low body weight. Authors speculate Pb may cause weight loss via gastrointestinal absorption damage.
Key numbers
- n = 1,274 participants (1,630 sampled, 1,274 included after exclusions).
- Sampling: 9 drinking water + 9 soil sites in Dapeng (Shenzhen); 6 water + 6 soil sites in Hengqin (Zhuhai).
- Analytical method: ICP-MS (Public Monitoring Center for Agro-product, Guangdong Academy of Agricultural Sciences).
- Exposure metric: Average daily dose (ADD) calculated per USEPA methodology for drinking water ingestion and soil ingestion routes.
- Heavy metal concentrations in water and soil: described as elevated relative to standards (specific concentration values presented in paper tables).
- T2DM association: no significant association with Pb or Cd ADD (all p > 0.05).
- Obesity association: 1 µg/kg bw/d Pb increase associated with 49.2–56.1% lower likelihood of overweight (BMI-based), WHR decrease 0.01–0.02, WC decrease 2.22–4.67 cm.
- 1 µg/kg bw/d Cd increase: associated with 100.9% higher likelihood of low body weight (Model 1).
- Basis: drinking water (µg/L) and soil (mg/kg); exact concentrations available in paper.
Methods (brief)
Cross-sectional design; ICP-MS for water and soil heavy metal measurement per Chinese national standards (GBT5750.2-2006 for water; soil quality guidelines). Dietary exposure estimated from water and soil ingestion only (not food); no blood or urine biomarkers for individual-level metal verification. USEPA ADD model for non-carcinogenic oral exposure. Logistic and linear regression with covariates. Limitation: ecological exposure assignment (community-level water/soil values applied to all residents) rather than individual biomonitoring; food-pathway exposure not quantified; cross-sectional design limits causal inference.
Implications
Certification: This paper provides real-world Pb and Cd concentration data from drinking water and soil in an e-waste-affected region of southern China, with simultaneous health outcome data in a large adult cohort. The water/soil contamination findings are directly relevant to HMT&C’s supply-chain risk assessments for ingredients sourced from southern China. Courses: Illustrates the multi-pathway exposure assessment model (water + soil ingestion); ADD calculation methodology; limitations of ecological exposure assignment vs. biomonitoring. App: Not directly applicable to food ingredient contamination profiles, but contextualizes Chinese regional exposure burden. Microbiome: Cd at high environmental concentrations is a known gut microbiome disruptor; cross-reference to gut-cadmium-axis pages.