Do Crops Grown at Urban Dumpsites Contain Metals at Levels that Pose Unacceptable Health Risks to Consumers?

Area of Science:

• Environmental Toxicology
• Public Health
• Food Safety

Background:

• Urban dumpsites contaminate soil, leading to metal accumulation in crops.
• Dietary exposure to metals in crops poses a global health risk, particularly in developing regions.
• Previous studies have not fully assessed the combined risks of multiple metals from diverse crops in simulated diets.

Purpose of the Study:

• To evaluate the health risks associated with dietary exposure to metals and metalloids in crops grown on the Mbale dumpsite in Uganda.
• To compare the noncancer and cancer risks between adult and child consumers.
• To identify specific crops contributing to the elevated health risks.

Main Methods:

• Sampling and analysis of 13 crop types for 11 metals and 2 metalloids.
• Creation of 12 meal classes simulating resident diets to estimate chronic dietary intake (CDI).
• Calculation of noncancer and cancer risks using established toxicological guidelines.

Main Results:

• Most crops and diets had insufficient selenium and exceeded permissible limits for Aluminum (Al), Iron (Fe), Nickel (Ni), Copper (Cu), Manganese (Mn), Lead (Pb), and Zinc (Zn).
• Children exhibited higher CDI (1.74 times) and consequently greater noncancer and cancer risks compared to adults.
• High noncancer risks were linked to Cobalt (Co), Chromium (Cr), Fe, Mn, and Zn, while Al was the primary contributor to cancer risks.

Conclusions:

• Crops grown on the Mbale dumpsite present significant noncancer and cancer risks, disproportionately affecting children.
• Specific vegetables like Amaranthus hybridus, Vigna unguiculata, Amaranthus dubius, and Cucurbita maxima significantly contribute to these risks.
• There is an urgent need for regulatory frameworks and enforcement of land/food policies to mitigate health risks from dumpsite-cultivated crops.