Enrichment Characteristics and Health Risk Assessment of Heavy Metals in Soil-Crop Systems

Overview

Liu et al. (2023) measured total arsenic, chromium, copper, lead, cadmium, and total mercury in paired crop and soil samples from Yuyao City, Zhejiang Province, China. The routeable occurrence values are the crop concentrations for rice, bayberry, and mustard; paired soil concentrations are useful supply-chain context but should not be routed as product occurrence. The paper reports average crop concentrations in mg/kg and variation coefficients for each metal.

Key numbers

Table 3 reports average crop metal contents in mg/kg; values in parentheses are the source-reported variation coefficients in %. The paper labels arsenic (As) and mercury (Hg) without speciation, so they are recorded here as total arsenic (tAs) and total mercury (tHg). The crop basis is not fully harmonized in the text: rice was described as a 500 g dry sample, while bayberry and mustard were collected as fresh samples and rinsed before storage.

Table 4 reports crop exceedance counts against the paper’s cited Chinese food-contaminant standards: bayberry lead (Pb) exceeded in 3 (8.8%) samples, mustard crop samples had no reported exceedances, and rice cadmium (Cd) exceeded in 5 (11.4%) samples. Soil exceedances were separate context: bayberry soil As 2 (5.9%), mustard soil Cu 1 (3.3%), and paddy soil Cu 3 (6.8%), Cd 1 (2.3%), and Hg 2 (4.5%).

Table 5 reports source-modeled non-carcinogenic HQ/HI values for crop ingestion. Bayberry HQ values were tAs 0.398, chromium (Cr) 0.197, Cu 0.065, Pb 0.077, Cd 0.035, and tHg 0.028, with HI 0.801; mustard HQ values were tAs 0.067, Cr 0.009, Cu 0.008, Pb 0.007, Cd 0.010, and tHg 0.002, with HI 0.105; rice HQ values were tAs 1.387, Cr 0.298, Cu 0.276, Pb 0.055, Cd 0.369, and tHg 0.058, with HI 2.444.

Methods (brief)

The study collected crop samples at harvest time and paired them with nearby 0-0.2 m soil samples. Rice ears were collected around each sampling point and mixed into a 500 g dry sample; mustard plants were collected as 2-3 kg fresh samples with roots removed; bayberry samples were collected from multiple positions on selected trees and mixed into a 1 kg fresh sample. Crop samples were digested with nitric acid for Cr, Cu, Pb, and Cd and with HNO3-HClO4 for As and Hg, then analyzed by ICP-MS and atomic fluorescence spectrometry. Soil samples were digested separately and analyzed by ICP-OES, ICP-MS, and atomic fluorescence spectrometry.

Implications

This source supports a local China occurrence route for rice grain, fresh fruit, and leafy vegetable matrices in a paired soil-crop setting. The crop averages should stay separated by matrix because bayberry, mustard, and rice show different metal patterns and different exceedance signals. Soil values can help explain source pathways and bioconcentration but should not be pooled with crop occurrence values.

Related evidence

• Rice
• Fruit
• Leafy Vegetables
• Rice (white, brown, wild — bulk grain)
• Fresh Fruit
• Leafy / Green Vegetables, Other
• Arsenic, Total
• Chromium
• Copper
• Lead
• Cadmium
• Mercury

Update history

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