Health Risks of Metals in Soils and Staple Foods from Floodplain Gardens

Jenn Hoskins
1st June, 2024

Health Risks of Metals in Soils and Staple Foods from Floodplain Gardens

Image Source: Natural Science News, 2024

Key Findings

  • Researchers from the Papua New Guinea University of Technology found high levels of Chromium (Cr) and Lead (Pb) in staple foods grown along the Watut River
  • The concentration of Pb in all samples and Cr in 97% of the foods exceeded safe limits set by FAO and WHO
  • Consuming these foods, especially bananas, poses significant health risks, including cancer, due to excessive metal intake
The health risks associated with the consumption of staple foods grown in subsistence food gardens along the Watut River in Papua New Guinea were investigated by researchers from the Papua New Guinea University of Technology[1]. This study focused on the concentrations of metals, specifically Chromium (Cr), Copper (Cu), Lead (Pb), and Nickel (Ni), in the soil and food samples and their potential health impacts on the local population. The study involved collecting twenty soil samples and twenty-nine samples of staple foods, including banana, taro, sweet potato, and Singapore taro, from food gardens. The concentration of metals in these samples was analyzed using an Inductively Coupled Plasma Optical Emission Spectrophotometer, a device that measures the presence of various elements in samples. The results showed that the mean metal concentration in the food garden soils followed the order: Cr > Cu > Ni > Pb. Alarmingly, the concentration of Pb in all samples and Cr in 97% of the staple foods exceeded the permissible limits set by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). This means that the levels of these metals were higher than what is considered safe for human consumption. Approximately 87% of adult consumers of bananas were found to have Cr and Pb ingestion levels exceeding the permissible daily intake of these metals (0.2 and 0.21 mg per day, respectively). The hazard index, a measure of the potential for non-carcinogenic health effects, indicated that the consumption of bananas posed the highest risk (9.40), followed by taro (7.32), sweet potato (6.13), and Singapore taro (4.30). This suggests that eating these foods could lead to significant health problems over time. The study also highlighted that the consumption of taro posed a cancer risk due to the intake of excessive Ni and Cr. The risk was more pronounced in adults, but non-carcinogenic hazards were found to be significant in children as well. This is consistent with previous findings in other regions, such as the Karnaphuli River estuary in Bangladesh, where children were found to be nearly six times more susceptible to non-carcinogenic and carcinogenic health effects than adults due to heavy metal contamination in fish[2]. The results of this study are in line with earlier research conducted in Ghana, which showed that heavy metal contaminants in food crops grown near mining centers posed health risks to consumers[3]. In that study, home processing methods like boiling, frying, and roasting were found to reduce the levels of heavy metals in food. However, in the case of the Watut River, the contamination levels were so high that even with processing, the risks might still be significant. Similarly, a study in Mashhad, Iran, assessed the health risks of heavy metals in drinking water and found that children were more vulnerable to the adverse effects[4]. This underscores the need for urgent measures to protect vulnerable populations, particularly children, from the harmful effects of heavy metal ingestion. In conclusion, the study conducted by the Papua New Guinea University of Technology reveals that the consumption of staple foods grown along the Watut River poses serious health risks due to high levels of Cr and Pb. These findings call for immediate actions to mitigate the contamination and protect the health of the local communities, especially children, who are at greater risk of non-carcinogenic and carcinogenic effects from these metals.



Main Study

1) Health risks of metals in soils and staple foods of the subsistence food gardens in the floodplains of Watut River, Papua New Guinea.

Published 31st May, 2024

Related Studies

2) Bioaccumulation of heavy metals in some commercially important fishes from a tropical river estuary suggests higher potential health risk in children than adults.

3) Effect of home processing methods on the levels of heavy metal contaminants in four food crops grown in and around two mining towns in Ghana.

4) Health risk assessments of arsenic and toxic heavy metal exposure in drinking water in northeast Iran.

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