Vanisree et al. 2022 — Heavy metal contamination of food crops: transport, toxicity, and management (IntechOpen chapter)

This open-access book chapter, published in the IntechOpen edited volume Environmental Impact and Remediation of Heavy Metals, reviews how heavy metals (Pb, Cd, As, Hg, Cr, Ni, Cu, Zn, Fe) enter agricultural soils and irrigation water from industrial, mining, agrochemical, and waste-disposal sources, accumulate in food crops via root uptake and xylem/phloem translocation, and produce toxicity in humans following dietary exposure. The chapter is narrative review throughout, with one tabulated dataset: heavy metal concentrations in effluent-contaminated irrigation water from the Dhaka Export Processing Zone (DEPZ), Bangladesh, drawn from a cited primary study. Geographic emphasis is Bangladesh (DEPZ industrial effluent) and India (general agricultural contamination); the authors are all affiliated with Indian forensic-science departments.

Key numbers

Effluent-contaminated irrigation water from Bangladesh DEPZ (chapter Table 1, attributed to cited source [21] in the chapter’s bibliography). Concentrations in mg/L; “safe limit” values are the comparators the chapter reports without further citation.

Against the safe limits the chapter cites:

• Pb mean 0.21 mg/L is within the 0.5 mg/L limit.
• Cr mean 0.43 mg/L is approximately 4.3× the 0.1 mg/L limit.
• Cd mean 0.06 mg/L is approximately 6× the 0.01 mg/L limit.

These are irrigation water concentrations, not food concentrations; they illustrate a contamination-source pathway, not the endpoint concentration in any specific crop or food product.

Other quantitative or semi-quantitative claims in the chapter are review-level statements (e.g., “wastewater-irrigated horticulture supplies ~50% of vegetables to some Asian and African metropolitan areas”; “10% of UK insecticides/fungicides historically contained Cu, Hg, Mn, Pb, or Zn”; “~30% of European sewage sludge is land-applied”). The chapter does not present primary crop or food concentration data — those numbers exist only in the cited references.

Methods (brief)

Narrative review chapter, no primary data generated. The Bangladesh DEPZ irrigation water table is reproduced from a cited primary source (the chapter’s reference [21]) and would need to be consulted directly for analytical method, sample size, and sampling period. The chapter discusses uptake mechanisms at the level of root apoplast/symplast cation transport, xylem/phloem mobilization via ZIP/NRAMP/YS/COPT transporter families, and oxidative-stress endpoints (GSH/GSSG ratios, phytochelatin induction), but does not generate primary data on any of these processes. Evidence tier B reflects book-chapter review status: useful for mechanistic background on soil-to-crop metal transport and for geographic context, but not a primary source of food contamination values.

The chapter is open-access under CC BY 3.0; DOI 10.5772/intechopen.101938.

Implications

Certification (HMTc): Mechanistic-background reference for supply-chain ingredient-origin screening rationale. The DEPZ irrigation water case supports the principle that geographic origin of soil/water is a legitimate screening criterion when evaluating ingredients sourced from industrial-discharge-affected agricultural zones. Does not contribute primary values for any threshold.

Courses: Supply-chain module reference for the soil-to-plant uptake section. The root > shoot > leaf > grain concentration gradient (with rice/wheat counterexamples for Cd under flooded conditions) is a useful teaching anchor for explaining why milling/polishing reduces but does not eliminate metals in cereal staples.

App: Not a source of food concentration values. Qualitative geographic-risk flag only: Bangladesh industrial-zone agricultural origin is elevated risk for Cd, Cr, and Pb in vegetables irrigated with surface water near textile/dyeing/garment/electroplating effluent.

Microbiome: Chapter touches soil-microbiome effects of heavy metals (citation [3]) but does not develop the topic. Not a useful microbiome source.

Verification notes

• 2026-05-18 (Claude Code, manual-fetch ingest cycle PCMF_80088): Page enhanced from prior 2026-05-14 revision. Fixed doi: null / no_doi_assigned: true — the chapter carries a valid DOI (10.5772/intechopen.101938) printed on every page footer and on the IntechOpen copyright page. License upgraded from generic "CC BY" to "CC BY 3.0" per the explicit Creative Commons URL on the IntechOpen copyright page (creativecommons.org/licenses/by/3.0/). Metals array expanded to include Cu, Zn, Fe — these are discussed in the chapter’s review of metals frequently co-occurring with Pb/Cd/Cr in industrial effluent and biosolids (chapter sections 2 and 3). Added access_url. Replaced legacy ## Wiki pages updated on ingest heading with ## Wiki pages this source may touch (current template). Tightened Key numbers to a table matching the chapter’s Table 1 exactly (Pb/Cr/Cd full distribution: mean, median, min, max, SD). Added Microbiome implication line (negative — chapter does not develop the topic).
• Identity-check provenance: this PDF is the chapter (IntechOpen open-access PDF, 15 pages, copyright 2022 The Author(s)). Title matches; authors match; DOI 10.5772/intechopen.101938 prints on every page footer.
• Brand firewall (Part 12): no brands named; chapter discusses categories of industries (textile, dyeing, garment, pharmaceutical, ceramic, paint, packing) without naming companies. No firewall edits required.
• Audit subagent (2026-05-18) flagged irrigation-water and soil-contamination in the “Wiki pages this source may touch” section as wikilinks to pages that do not yet exist on disk (wiki/supply-chain/ currently contains only aluminum-based-packaging.md, soil-nickel-screening.md, and index.md). Verified: those two pages are not yet created. Leaving the wikilinks intact since they are semantically the correct routing destinations and will resolve once Karen creates the parent supply-chain coverage pages; they are not silently inventing taxonomy slugs. Subagent verdict was PROMOTE with this as a minor concern, not a blocker.

Wiki pages this source may touch

• rice — review-level mention of Cd accumulation under flooded paddy conditions (citations [83], [84]); not a primary value contributor.
• wheat — review-level mention only; not a primary value contributor.
• vegetables — review-level discussion of vegetable contamination in Bangladesh DEPZ context; not a primary value contributor (Bangladesh DEPZ vegetable values trace to chapter reference [21], which should be ingested separately).
• irrigation-water — primary value contributor: DEPZ effluent table.
• soil-contamination — mechanistic-background contributor.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.