Zinc (Zn)

Overview

Zinc is an essential nutrient and is not one of the toxic metals at the center of food-contamination concern. The Index nevertheless carries this page because zinc appears in elemental-survey sources alongside the toxic-metal analytes — many ICP-MS multi-element methods report zinc as part of the standard analyte set, and some toxicology sources covering cadmium and lead also discuss zinc as a competing-uptake or co-toxicity context. Zinc is in scope only as cross-metal context, not as a contamination analyte in its own right.

The essential-vs-toxic boundary for zinc is dose-dependent. Adequate zinc intake supports immune function, wound healing, and child growth; insufficient zinc produces deficiency syndromes prevalent in some populations. High-dose chronic intake can cause copper deficiency, immune impairment, and gastrointestinal effects. Because zinc’s primary food-safety question is nutritional adequacy rather than contamination, it falls outside the scope of a toxic-metal contamination index, which addresses the presence of unwanted contaminants rather than the sufficiency of essential nutrients.

For infant formula and baby food, zinc is included in regulatory composition requirements rather than contamination limits — the question is whether enough zinc is present, not whether too much is. EU compositional rules for infant formula set minimum and maximum zinc levels per 100 kcal; FDA rules similarly. The Heavy Metal Index does not synthesize zinc compositional adequacy because that work belongs to pediatric-nutrition references rather than to a heavy-metals-in-food index.

Where source pages declare metals: arrays including Zn alongside the toxic-metal analytes, the routing audit attaches the source to this page automatically. The Index records the zinc values for completeness as cross-metal context.

Ufelle & Barchowsky 2021 attaches zinc as an essential-metal-with-toxicity-potential node, covering zinc transport, essentiality, deficiency, high-dose toxicity, metal fume fever, neuronal toxicity, and pancreatic toxicity context. It is a toxicology source, not a food occurrence dataset.

Human exposure source

Association of exposure to synthetic phenols and metal(loid)s with early puberty in Spanish girls: a multicentric case–control study reports urinary metal biomarkers and early-puberty associations in girls recruited across six Spanish hospitals during 2018–2022. The source keeps case and control summaries, detection frequencies and observational effect estimates separate. A single urine measurement and case–control sampling cannot establish exposure before puberty onset, causality, or a particular consumer-product source.

Prepared cosmetic-clay source

Nkosi and Thembane (2024) report zinc findings in market-purchased clays used for topical sun protection in Durban, South Africa. The measurements concern dried and ground material from a limited local sampling frame. They do not establish zinc concentrations in formulated sunscreen, release to skin or absorbed dose.

Chromium research: qualified source context

One Nilore, Islamabad soil characterization reported zinc of 26.73 µg/g by bulk elemental analysis (Table 2). The source does not state a wet/dry basis or replicated uncertainty. This is a local soil result; it does not measure food occurrence or crop transfer. LABORATORY SCALE ELECTROKINETIC REMEDIATION OF HEXAVALENT CHROMIUM FROM CONTAMINATED SOIL

Nahavand farm study: evidence limitations

A Nahavand farm study states sugar-beet biomass zinc greater than 3,400 mg/kg dry weight, while its crop panel has an axis ending near 600 mg/kg. The discrepancy remains unresolved; the high value is not silently reassigned to soil. Whole aerial biomass cannot establish sugar-beet-root concentrations (Results p10; Figure 3). Soil–water–crop pathways of heavy metal contamination and human health risks in intensive smallholder farms of the Nahavand Plain, Iran

Arzew surface-soil survey

Fourteen industrial-zone soils near Arzew had zinc mean 147.36 mg/kg, median 137.56 mg/kg and maximum 285.7 mg/kg. The mapped surface extends above 400 mg/kg, a separate graphical result that does not replace observed extrema. These are air-dried soil summaries, with no measured crop uptake (Boudia et al. 2019, Table 2; Figure 3). Spatial contamination and health risks of heavy metal(loid)s in surface soils from a petrochemical complex in the north-eastern region of Algeria

Banat soil–nettle–snail study

Nica et al. report a soil-to-nettle zinc correlation of 0.93 (P<0.01) across their Banat field sites (2012, Table 1). Figure 2 shows differing zinc burdens in snail foot and hepatopancreas. The soil measurement is a dilute-nitric-acid extract, and tissue concentrations are dry-weight values from pooled wild snails. Neither the correlation nor the graphical concentration estimates establish zinc levels in consumer foods. Bioaccumulative and conchological assessment of heavy metal transfer in a soil-plant-snail food chain

Ganga freshwater-fish study: qualified evidence

Maurya et al. report 32.41 ± 2.55 µg/g zinc in L. rohita gill, rather than C. catla gill as stated in their abstract (2019, Table 4). The abstract’s 4.77 ± 0.34 µg/g example is a lead result in C. reba gill, not zinc. Table values retain their explicit tissue assignment and unresolved wet/dry basis; neither gill result is a muscle-food observation. Bioaccumulation and potential sources of heavy metal contamination in fish species in River Ganga basin: Possible human health risks evaluation

Frequently asked questions

Sources

• Determination of 40 Elements in Powdered Infant Formulas and Related Risk Assessment
• Zinc and Cadmium Compounds (Chapter Seven), in Patty's Toxicology, Sixth Edition
• Ufelle & Barchowsky 2021

References

Works cited in this page’s text, in first-appearance order. See Sources for this page’s source inventory. Each title links to its source record, which carries the ingest receipt, the extracted values, and the file hash of the document it was built from.

1. Toxic Effects of Metals (Chapter 23), in Casarett & Doull’s Essentials of Toxicology, Fourth EditionUfelle AC and Barchowsky A · Casarett & Doull’s Essentials of Toxicology, Fourth Edition. McGraw Hill Education · 2021 · www.mhprofessional.comTextbook
2. Association of exposure to synthetic phenols and metal(loid)s with early puberty in Spanish girls: a multicentric case–control studyOlivas-Martinez A, Escribano A, Riaño-Galán I, Torrebias M, Olmedo P, Gil F, et al. · European Journal of Pediatrics 185:295 · 2026 · doi.org/10.1007/s00431-026-06919-1Peer-reviewed
3. Physical, chemical and biological characteristics of clays from Durban (South Africa) for applications in cosmeticsS’busiso M Nkosi and Nokukhanya Thembane · Analytical Science Advances · 2024 · doi.org/10.1002/ansa.202300062Peer-reviewed
4. LABORATORY SCALE ELECTROKINETIC REMEDIATION OF HEXAVALENT CHROMIUM FROM CONTAMINATED SOILM. Khalid, N. Ahmed, and R. M. Qureshi · The Nucleus 45(1–2):55–61 · 2008 · doi.org/10.71330/nucleus.45.01-2.998Peer-reviewed
5. Soil–water–crop pathways of heavy metal contamination and human health risks in intensive smallholder farms of the Nahavand Plain, IranSaeed Sharafi, Maryam Sharafi, and Maryam Lorvand · Scientific Reports 16:9947 · 2026 · doi.org/10.1038/s41598-026-38637-xPeer-reviewed
6. Spatial contamination and health risks of heavy metal(loid)s in surface soils from a petrochemical complex in the north-eastern region of AlgeriaHayat Boudia, Laurent Vassalo, Mohammed Hadjel, Pascale Prudent, and Jean-Luc Boudenne · International Journal of Environmental Science and Technology 16:4707–4718; HAL author-manuscript version read · 2019 · doi.org/10.1007/s13762-018-02195-1Peer-reviewed
7. Bioaccumulative and conchological assessment of heavy metal transfer in a soil-plant-snail food chainDragos V Nica, Marian Bura, Iosif Gergen, Monica Harmanescu, and Despina-Maria Bordean · Chemistry Central Journal 6:55 · 2012 · doi.org/10.1186/1752-153X-6-55Peer-reviewed
8. Bioaccumulation and potential sources of heavy metal contamination in fish species in River Ganga basin: Possible human health risks evaluationPradip Kumar Maurya, D. S. Malik, Krishna Kumar Yadav, Amit Kumar, Sandeep Kumar, and Hesam Kamyab · Toxicology Reports 6:472–481 · 2019 · doi.org/10.1016/j.toxrep.2019.05.012Peer-reviewed
9. Study of Peculiarities of Accumulation of Heavy Metals and Arsenic in Medicinal Plant Raw Materials of Synanthropic Flora of Voronezh RegionNina Alekseevna Dyakova · Khimiya Rastitel’nogo Syr’ya 2:163–170 · 2023 · doi.org/10.14258/jcprm.20230211725Peer-reviewed
10. Efficacy Of Aloe Vera Powder in Bioremediation of Heavy Metals from Waste WaterMaleeha Shamsher, Atifa Tajammal, Aisha Waheed Qurashi, and Uzma Rafi · MARKHOR (The Journal of Zoology) 3(1):13–18 · 2022 · doi.org/10.54393/mjz.v3i1.37Peer-reviewed
11. Yield Assessment of Beetroot and Potato, Cultivated on Ordinary Chernozem Contaminated with Heavy MetalsN. V. Gromakova · Vegetable Crops of Russia 5(38):74–75 · 2017 · doi.org/10.18619/2072-9146-2017-5-74-75Peer-reviewed
12. Removal of Heavy Metals from Industrial Sludge Using Soil Washing TechniqueJ. Sumalatha, B. P. Naveen, and R. K. Malik · Asian Journal of Water, Environment and Pollution 16(3):83–89 · 2019 · doi.org/10.3233/ajw190036Peer-reviewed
13. Analysis of a Wild Leafy Vegetable (Premna latifolia Roxb.) Samples for Essential Trace Elements using ICP - MS TechniqueG. Narayana Murthy and Balarama Swamy Yadav Padala · International Journal of Scientific Engineering and Research 12(2):1–4 · 2024 · doi.org/10.70729/se24205180530Peer-reviewed
14. HEAVY METALS ACCUMULATION IN SOIL AND CELERY ROOT (APIUM GRAVEOLENS L.) HARVESTED FROM THE POLLUTED AREAS IN SIBIU COUNTY, CENTRAL ROMANIABogdan Ștefan Oprea, Nicoleta Olimpia Vrînceanu, Dumitru-Marian Motelică, Georgiana Iuliana Plopeanu, Vera Carabulea, and Mihaela Costea · Annals of the University of Craiova—Agriculture,Montanology,Cadastre52(1):422–429 · 2022 · doi.org/10.52846/aamc.v52i1.1370Peer-reviewed
15. Assessment of the Risk of Heavy Metals Accumulation in Vegetable CropsVladimir N. Bashkin and Rosa A. Galiulina · Issues of Risk Analysis18(4):48–65 · 2021 · doi.org/10.32686/1812-5220-2021-18-4-48-65Peer-reviewed
16. Application of principal component analysis in the pollution assessment with heavy metals of vegetable food chain in the old mining areasIosif Gergen and Monica Harmanescu · Chemistry Central Journal6:156 · 2012 · doi.org/10.1186/1752-153x-6-156Peer-reviewed

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Additional geographic and remediation evidence

Nina Alekseevna Dyakova, 2023. Dyakova compares nine elements in medicinal plant materials collected in disturbed and control environments in Russia’s Voronezh region during 2015–2020. The reported ranges preserve tissue and environmental setting; the paper also proposes regional background means across species. Supports geographic and tissue-specific contamination evidence for botanical raw materials and environmental attribution hypotheses. It does not measure finished supplements or isolate an individual polluter’s causal contribution.

Maleeha Shamsher, 2022. This laboratory paper tests aloe leaf powder for zinc and sodium adsorption. It is retained as remediation literature with serious quantitative limitations: negative zinc concentration estimates and a reported 500% sodium removal invalidate the paper’s efficacy claims as treatment evidence. Documents an attempted biosorption approach and a reproducibility gap. It cannot support validated percentage removal, potable-water safety or aloe-based treatment efficacy. Sodium data are auxiliary diagnostics.

N. V. Gromakova, 2017. A 2015 Rostov-region field experiment measured copper, zinc and lead in beetroot and potato grown on artificially metal-amended chernozem. Adding mineral fertilizer reduced several crop concentrations relative to the metal-only treatment, while yield responses differed between crops. Supports crop-specific agronomic mitigation and soil-to-crop transfer evidence. Artificially amended experimental crops are not a market-occurrence distribution. Paper limit comparisons remain secondary context.

J. Sumalatha, 2019. Column washing of Bangalore-area industrial sludge removed substantially more metals with hydrochloric acid plus EDTA than with distilled water. This is a remediation experiment relevant to sludge contamination pathways, with no measurements in food or a demonstrated safe land-application endpoint. Supports laboratory washing and contaminant-transport comparisons. Metal-rich leachate still requires management; the study does not establish agricultural reuse or field-scale safety.

G. Narayana Murthy, 2024. Premna latifolia leaves collected in three Andhra Pradesh villages had different reported elemental concentrations. Village-specific values are preserved as local leafy-vegetable evidence; the paper supplies no replicate counts or uncertainty estimates. Supports geographic variation in six elements in a specific wild edible leaf. It does not establish nutritional adequacy, safety, or a regional market distribution. The source’s characterization of aluminium as an essential nutrient is not adopted.

Bogdan Ștefan Oprea, 2022. Celery roots and garden soils from 26 households in a historically polluted Romanian area showed wide cadmium and lead variation in 2021–2022. Soil results use dry weight, while edible celeriac results use fresh weight; these paired measurements preserve a legacy-contamination pathway without assigning sole liability to any facility. Supports historical industrial-burden and present edible-root occurrence evidence. Celery here is celeriac, not stalk celery; product routing is root/tuber vegetables. Geographic sampling is targeted to a polluted area and is not a national market sample.

Vladimir N. Bashkin, 2021. Bashkin and Galiulina review vegetable-associated metal exposure assessment and microbial/agronomic risk-management approaches. Chinese and Russian case-study values are secondary reports; they remain traceable to the cited studies and are not counted as new independent occurrence samples. Supports exposure-method and remediation literature discovery. Bacterial effects can increase as well as decrease uptake depending on organism, metal and plant; the review does not establish a universal inoculant intervention. Secondary model outputs are not contemporary health or certification thresholds.

Iosif Gergen, 2012. Gergen and Harmanescu analyze metal contamination patterns across two historic Romanian mining areas and a reference area. Their PCA study reproduces vegetable concentrations and male hazard quotients from the earlier Harmanescu 2011 study; these remain linked secondary observations rather than additional independent samples. Supports legacy mining and tissue/region differences. Parsley root and leaf remain distinct, as do carrot root and leaf. The fresh-matter food table is retained with cohort linkage so that a reanalysis cannot inflate the evidence pool. Source THQ rankings are model results, not clinical outcomes.