Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was reviewed?
This review article synthesizes evidence on heavy metal contamination certification needs across the agricultural soil–plant–food chain continuum, with emphasis on chromium, arsenic, nickel, cadmium, lead, mercury, zinc, and copper as the principal heavy metals of concern. It maps sources from geogenic parent materials and weathering to anthropogenic inputs, including mining, smelting, fossil-fuel combustion, fertilizers, pesticides, wastewater irrigation, biosolids, and urban runoff, and details how these metals alter soil physicochemical properties, disrupt plant metabolism, and ultimately contaminate human foods. The article also compiles toxicological endpoints in humans and summarizes remediation classes—physical, chemical, biological, adsorption, membrane, advanced oxidation, and ion exchange—framed as actionable pathways for heavy metal contamination certification standards. The paper’s structure is reinforced by infographics on sources, crop effects, human organ risks, and remediation taxonomies.
Who was reviewed?
The reviewed evidence spans soils influenced by industrial and agricultural activities worldwide, crops ranging from grains and vegetables to fruits, and human populations exposed via drinking water and foods, with case exemplars from South Asia and Africa highlighting elevated risks near tanneries, petrochemical zones, and wastewater-irrigated farms. Microbial communities, mycorrhizal fungi, and plant developmental stages are considered as sensitive biological receptors mediating uptake and transfer. Regulatory touchpoints include metals prioritized by ATSDR and WHO, aligning the synthesis with risk-based thresholds pertinent to heavy metal contamination certification for agricultural commodities and inputs.
Most important findings
| Critical point | Details |
|---|---|
| Priority metals and ubiquity | Cr, As, Ni, Cd, Pb, Hg, Zn, and Cu are prevalent in soils, waters, foods, and air; ATSDR and WHO designate Hg, Pb, Cd, and As as especially hazardous for plants and humans. |
| Dominant sources | Anthropogenic inputs—mining/smelting, industrial effluents, fossil-fuel combustion, fertilizers, pesticides, biosolids, and wastewater—are the principal drivers of agricultural soil burdens; natural sources include parent rocks and weathering. |
| Soil microbiome disruption | Metals reduce microbial biomass and diversity, suppress enzyme systems (e.g., urease, phosphatases), perturb nutrient cycling, and alter soil pH and aggregation, degrading fertility and ecosystem function. |
| Soil physical–chemical degradation | Accumulation destabilizes aggregates, reduces porosity and water-holding capacity, shifts pH, perturbs redox equilibria, and adsorbs strongly to clays/organic matter, limiting bioavailability yet creating legacy stores. |
| Plant-level toxicity | Biomagnification is documented across vegetables, rice, fish, and milk; chronic exposures are associated with renal, cardiovascular, neurological, and carcinogenic outcomes; children are especially vulnerable. |
| Food-chain transfer and human risk | Biomagnification is documented across vegetables, rice, fish, and milk; chronic exposures associated with renal, cardiovascular, neurological, and carcinogenic outcomes; children are especially vulnerable. |
| Exceedances vs. limits | WHO-referenced exceedances over maximum tolerable limits (MTLs) reported for Cu, Cr, Cd, Zn, As, and Pb in multiple contexts, underscoring certification-relevant monitoring needs. HeavymetalHeliyon |
| High-risk scenarios | Tanneries discharging untreated effluent, petrochemical corridors, roadside agriculture, and wastewater irrigation present consistent hotspots requiring priority control and certification safeguards. |
| Remediation toolbox | Decision classes include excavation/soil washing; stabilization/solidification and electrokinetics; phytoremediation/bioleaching; adsorption (biochar, activated carbon); membranes; AOPs; and ion exchange. |
| Research gaps | Interactions among mixed metals, genotype-specific plant tolerance, intergenerational transfer, and microplastics as HM vectors remain underexplored, limiting precise risk modeling for certification. |
Key implications
Primary regulatory impacts include aligning HTMC thresholds with ATSDR and WHO priority metals and contexts of exceedance; certification requirements should mandate source-tracking, soil–plant–water testing, and remediation verification; industry applications span raw material audits, wastewater controls, and input screening; research gaps on metal mixtures, crop genotypes, and microplastics constrain standard setting; practical recommendations prioritize hotspot mapping, matrix-specific MTLs, audited remediation plans, and continuous surveillance within the heavy metal contamination certification workflow.
Citation
Angon PB, Islam MS, KC S, Das A, Anjum N, Poudel A, Suchi SA. Sources, effects and present perspectives of heavy metals contamination: Soil, plants and human food chain. Heliyon. 2024;10:e28357. doi:10.1016/j.heliyon.2024.e28357
Heavy metals are high-density elements that accumulate in the body and environment, disrupting biological processes. Lead, cadmium, arsenic, mercury, nickel, tin, aluminum, and chromium are of greatest concern due to persistence, bioaccumulation, and health risks, making them central to the HMTC program’s safety standards.
Chromium (Cr) is a widely used metal with significant public health implications, especially in its toxic hexavalent form. The HMTC program’s stricter regulations ensure that chromium exposure is minimized, safeguarding consumer health, particularly for vulnerable populations.
Arsenic is a naturally occurring metalloid that ranks first on the ATSDR toxic substances list. Inorganic arsenic contaminates water, rice and consumer products, and exposure is linked to cardiovascular disease, cognitive deficits, low birth weight and cancer. HMTC’s stringent certification applies ALARA principles to protect vulnerable populations.
Nickel is a widely used transition metal found in alloys, batteries, and consumer products that also contaminates food and water. High exposure is linked to allergic contact dermatitis, organ toxicity, and developmental effects, with children often exceeding EFSA’s tolerable daily intake of 3 μg/kg bw. Emerging evidence shows nickel crosses the placenta, elevating risks of preterm birth and congenital heart defects, underscoring HMTC’s stricter limits to safeguard vulnerable populations.
Cadmium is a persistent heavy metal that accumulates in kidneys and bones. Dietary sources include cereals, cocoa, shellfish and vegetables, while smokers and industrial workers receive higher exposures. Studies link cadmium to kidney dysfunction, bone fractures and cancer.
Lead is a neurotoxic heavy metal with no safe exposure level. It contaminates food, consumer goods and drinking water, causing cognitive deficits, birth defects and cardiovascular disease. HMTC’s rigorous lead testing applies ALARA principles to protect infants and consumers and to prepare brands for tightening regulations.
Mercury (Hg) is a neurotoxic heavy metal found in various consumer products and environmental sources, making it a major public health concern. Its regulation is critical to protect vulnerable populations from long-term health effects, such as neurological impairment and cardiovascular disease. The HMTC program ensures that products meet the highest standards for mercury safety.
