Spatial distribution and risk assessment of fluorine and cadmium in rice, corn, and wheat grains in most karst regions of Guizhou province, China

Overview

This study mapped the spatial distribution of cadmium (Cd) across 334 grain samples (rice, corn, wheat) collected from karst farming regions of Guizhou province, China, a zone known for elevated natural Cd background due to karst geology. Cadmium concentrations ranged widely, and exceedance rates against the Chinese national standard (GB 2762-2017: 0.2 mg/kg for rice, 0.1 mg/kg for corn and wheat) were substantial, especially in wheat (45.1%). The paper also addressed fluorine, but Cd is the primary heavy-metal finding of wiki relevance.

Key numbers

Sample n: 334 total (113 rice, 119 corn, 102 wheat). Cadmium ranges: rice 0–463 µg/kg (mean not extracted from abstract, flagged for table review); corn 0–307 µg/kg; wheat 12–537 µg/kg. Exceedance rates against Chinese standard (0.2 mg/kg rice, 0.1 mg/kg corn/wheat): rice 11.6%, corn 13.5%, wheat 45.1%. Method: ICP-MS. Jurisdiction: Guizhou province, CN.

Methods (brief)

ICP-MS on acid-digested grain samples. Spatial mapping using GIS-based interpolation across karst regions. Risk assessment using hazard quotient (HQ) and cancer risk methods. n=334 samples across three crops.

Implications

Certification: Guizhou wheat at 45.1% exceedance rate against Chinese 0.1 mg/kg limit is a high-risk origin for wheat-containing products. Corn exceedance at 13.5% is also significant. Sourcing decisions for grain ingredients should screen for Guizhou karst origin. Courses: Illustrates geology-driven (karst) Cd contamination vs. industrial sources; strong case study for origin-specific supply chain risk. App: Supports geographic_breakdown entries for Cd in rice, corn, and wheat; Guizhou karst region warrants elevated risk flagging.

Wiki pages updated on ingest

• Rice
• Corn
• Wheat
• Cadmium
• china-gb-2762

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