Assessment of Potentially Toxic Metals in Cucumbers (Cucumis sativus) from Peninsular Malaysia: Evaluating Human Health Risks

Assessing Heavy Metal Contamination in Cucumbers from Peninsular Malaysia: A Health Risk Perspective

Heavy metal contamination in vegetables poses significant health risks, especially when these metals accumulate in edible crops. A recent study, as detailed in IGMIN Research Article #200, investigates the concentrations of potentially toxic metals (PTMs) in cucumbers (Cucumis sativus) collected from four farming regions in Peninsular Malaysia. This research highlights both the contamination levels and the associated human health risks.

Introduction: The Risk of Heavy Metal Contamination

Heavy metals such as iron (Fe), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) can enter the food chain through contaminated soil and water. These metals, when present above safe limits, pose risks including organ damage, developmental disorders, and in severe cases, poisoning. Cucumber, a widely consumed vegetable, can accumulate these metals, making regular monitoring essential.

Sources of Contamination

Agricultural Practices: Use of wastewater irrigation, pesticides, and fertilizers.
Industrial Activities: Mining, manufacturing, and urban waste discharge.
Environmental Deposition: Atmospheric deposition of pollutants onto soil and crops.

Objectives of the Study

The study had two primary goals:

To evaluate the concentrations of Fe, Cu, Ni, Pb, and Zn in cucumbers collected from selected farming areas.
To assess the human health risk associated with the consumption of these cucumbers.

Methodology

Sampling Locations

Samples were collected from four regions:

Kg Ara Kuda (Penang)
Kg Sitiawan (Perak)
Kuala Ketil (Kedah)
Jerantut (Pahang)

Analysis Techniques

Sample Preparation: Cucumbers were washed, dried, ground, and analyzed.
Metal Detection: Flame atomic absorption spectrophotometry (AAS) was used to measure metal concentrations.
Health Risk Assessment: Metrics like Estimated Daily Intake (EDI) and Target Hazard Quotient (THQ) were calculated to evaluate non-carcinogenic risks.

Key Findings

1. Metal Concentration Levels

The concentrations of Cu, Fe, Ni, Pb, and Zn in cucumbers were below the maximum permissible limits set by Malaysian food regulations.
Cu ranged between 9.56–13.6 mg/kg (dry weight), while Zn varied from 17.5–62.0 mg/kg across the regions.

2. Estimated Daily Intake (EDI)

EDI values were calculated based on cucumber consumption rates for adults (345 g/day) and children (232 g/day).
All EDI values for Fe, Cu, Ni, Pb, and Zn were within safe limits, indicating minimal immediate risk.

3. Target Hazard Quotient (THQ)

THQ values for all metals were below 1.0 for both adults and children.
This suggests no significant non-carcinogenic risk associated with the consumption of cucumbers from the studied regions.

Discussion: Implications for Public Health

1. Comparisons with Other Studies

The contamination levels in Peninsular Malaysia were lower compared to regions with heavy industrial activity, such as Guangdong, China.
Consistent with global research, cucumbers showed higher metal accumulation when grown in contaminated soils.

2. Children’s Higher Risk

While all THQ values were safe, children exhibited higher THQ values than adults due to their lower body weight and higher relative consumption.

3. Recommendations for Risk Mitigation

Soil and Water Testing: Regular monitoring of farming areas to identify contamination hotspots.
Controlled Irrigation: Use of treated water instead of untreated wastewater.
Consumer Awareness: Educating the public about washing and peeling vegetables to reduce surface contamination.

Future Research Directions

While this study provides critical insights, further investigation is needed to:

Assess long-term health risks associated with chronic exposure to low-level contamination.
Explore bioaccumulation trends in other edible crops from the same regions.
Develop cost-effective methods for soil remediation in contaminated areas.

Conclusion

The study concludes that cucumbers grown in Peninsular Malaysia pose minimal health risks concerning PTMs. However, continued monitoring and proactive measures are essential to maintain food safety standards. Effective pre-harvest interventions, such as using clean irrigation water and adopting sustainable farming practices, can further minimize contamination risks.

By addressing these challenges, Malaysia can ensure that its agricultural produce remains safe for consumption, supporting both public health and economic stability.