Overview
Hussain and colleagues reviewed arsenic, cadmium, lead, mercury, and nickel contamination in plant-based foods. The chapter is not a primary sampling study; it compiles literature tables for cereal grains, vegetables, fruits, nuts, pulses, and plant oils. This page records the review-level ranges and routing context only, and downstream quantitative pooling should prefer the underlying primary studies when those are already in the corpus or can be retrieved.
Key numbers
The chapter summarizes occurrence tables for plant-based foods as mg kg−1 in the edible portions or product matrices used by the cited studies:
| Food category | Review-level finding |
|---|---|
| Cereal grains | Table 3 compiles As, Cd, Pb, Hg, and Ni in cereal grains. The prose states that arsenic in cereal grains ranged from 0 to 1.70 mg kg−1. Mercury in cereal grains was always below the maximum permissible level of 0.10 mg Hg kg−1 in the reviewed table. Nickel in many market-survey cereal grains was within ≤0.65 mg kg−1, but oat and millet from Finnish food stores reached up to 1.90 mg kg−1, and rice from Vietnam had maximum Ni 2.02 mg kg−1. |
| Vegetables | Table 4 compiles edible portions of vegetables. The prose states that arsenic in vegetables ranged from 0 to 2.90 mg kg−1. The chapter uses Cd limits of ≤0.20 mg kg−1 for leafy vegetables and ≤0.05 mg kg−1 for other vegetables, and reports examples above those limits. It states that mercury was not accumulated to toxic levels in the vegetables listed, while Ni in most vegetables was within ≤6.67 mg kg−1 but some wastewater-irrigated or peri-urban examples reached much higher values, including 85 mg Ni kg−1 in Morocco and 506 mg Ni kg−1 in India. |
| Fruits | Table 5 compiles fruit studies. The prose states that arsenic above 0.10 mg kg−1 was generally not reported in fruits, although some market surveys in Botswana and Bangladesh had unsafe levels. Mercury in fruits listed in Table 5 was below 0.10 mg kg−1. Nickel in most fruits was within ≤2.92 mg kg−1, but some examples exceeded this, including mulberry in Serbia at 3.60 mg Ni kg−1 and selected fruits from Nigeria, Libya, Turkey, and Pakistan. |
| Nuts | Table 6 compiles nuts. The prose states that arsenic in nuts from Swedish and South African markets was within ≤0.10 mg kg−1; Cd in hazelnuts, walnuts, and almonds from Sweden, Spain, and Germany was within ≤0.05 mg kg−1; Hg in miscellaneous nuts from UK and Swedish markets was within 0.10 mg Hg kg−1; and Ni was within permissible levels except for cashew nuts from a Swedish market. |
| Pulses | Table 7 compiles pulses. The prose states that arsenic in pulses from India was within ≤0.10 mg kg−1, while market pulses from Pakistan, Bangladesh, and India ranged from 0.01 to 1.80 mg As kg−1. Cd in some pulses from Pakistan, India, China, and Ethiopia exceeded ≤0.10 mg kg−1. Pb in nearly all pulses from market surveys in India, Nigeria, Turkey, Egypt, and Spain was within ≤0.20 mg kg−1, while some Pakistan and Ethiopia results exceeded that level. Mercury in pulses was within ≤0.10 mg kg−1; Ni in selected Nigerian market pulses was within ≤0.38 mg kg−1, but contaminated or peri-urban pulses and some Pakistan market samples exceeded it. |
| Plant oils | Table 8 compiles plant oils. The prose states that all plant oils had safe levels of As, Cd, Pb, Hg, and Ni; Table 8 lists a maximum permissible limit of As 0.10 mg kg−1, Cd 0.05 mg kg−1, Pb 0.10 mg kg−1, Hg 0.10 mg kg−1, and Ni 3.43 mg kg−1. |
The source also states that more than 80% of human cadmium (Cd) intake was estimated to come from cereals and vegetables, citing Khan et al. 2014; this is review context and not a measurement made by this chapter.
Methods (brief)
This is a literature-review chapter in an edited Springer volume. It summarizes plant-based food categories, toxicological context for arsenic (As), Cd, lead (Pb), mercury (Hg), and nickel (Ni), compiled occurrence tables, and sources/remedies for contaminated soils and irrigation water. The chapter does not describe a new sampling frame, analytical instrument, or laboratory method because it does not generate primary analytical data.
Implications
This source is useful as a broad map of plant-food occurrence literature and as a triage guide for primary-study retrieval. It should not be treated as a clean benchmark distribution because the tables combine countries, sample types, study designs, contamination settings, and analytical bases. Where underlying primary studies are available, their source pages should carry the routeable values; this review should remain broad context for cereals, vegetables, fruits, pulses, nuts, and plant oils.
Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git.
| Commit | Date | Change | Description |
|---|---|---|---|
| b01ec52c31 | 2026-08-04 | major | 1 section added |
| 3171d069e3 | 2026-08-02 | major | 1 section added |
| 90a2f9a38e | 2026-07-30 | major | 1 section added and 1 removed |
| eaa8eeeedf | 2026-07-27 | major | 1 section added and 1 removed |
| aca5e2155a | 2026-06-09 | major | 1 section added |