Heavy Metals in Cameroon’s Chicken Meat and Eggs Raise Health Concerns for Children

Chicken meat and eggs from poultry farms in three major production regions of Cameroon carry measurable levels of six heavy metals, and the resulting dietary exposure may exceed safe thresholds for some consumers, particularly children, according to a new study published in the journal Food Safety and Risk.

The team surveyed 900 households, 300 in each of the three regions, using cross-sectional cluster sampling. Each region was divided into thirty clusters of ten households, selected by a quota method with a randomly defined starting point. Respondents had to have lived in the area for at least two years and be at least eighteen years old. A structured questionnaire collected information on household members, the frequency and quantity of chicken and egg consumption, and knowledge of heavy metals. The researchers converted reported consumption into edible mass by accounting for bones, which make up on average 71.1 percent of a chicken part, and eggshells, which account for about 12.8 percent of an egg. Households were then classified as low, medium, or high consumers depending on their daily intake.

For the contamination analysis, the researchers collected 48 broiler chickens aged 45 days, weighing between 1.8 and 2 kilograms, and 180 eggs from laying hens across twelve farms, two broiler farms and two laying hen farms per region. Six composite samples per matrix, two per region, were digested with nitric acid and hydrogen peroxide and analyzed by inductively coupled plasma optical emission spectrometry, a technique that detects elements by the characteristic radiation they emit in a plasma ionization source. Certified reference standards from the National Institute of Standards and Technology were used for quality control.

The measurements revealed a striking pattern of accumulation. Cadmium concentrations in chicken muscle ranged from 27.3 to 29.6 micrograms per kilogram, exceeding the recommended maximum of 10 micrograms per kilogram for animal tissues. Mercury in liver samples ranged from 798.3 to 845.5 micrograms per kilogram, more than one order of magnitude above the recommended limit of 3 micrograms per kilogram. Chromium levels varied between 53.7 and 60.4 micrograms per kilogram in muscle and 13.7 to 15.0 micrograms per kilogram in liver, both above the allowable concentration of 2 micrograms per kilogram. The highest cadmium, arsenic, chromium, and mercury concentrations in muscle came from the West region, while the highest lead, arsenic, chromium, and mercury levels in liver were found in the Central region. The authors attribute the elevated liver mercury to the organ’s physiological role in uptake, metabolism, and storage of toxic elements, and suggest bioaccumulation through contaminated feed as the most likely source.

Eggs told a different story. All six heavy metals were detected in every egg sample, with concentrations ranging from 3.4 to 4.6 micrograms per kilogram for lead, 0.5 to 0.7 for nickel, 3.2 to 3.7 for arsenic, 9.2 to 9.9 for cadmium, 0.8 to 1.2 for chromium, and 3.3 to 3.6 for mercury. Except for mercury, which exceeded the recommended maximum of 3 micrograms per kilogram in all three regions, egg concentrations remained below their respective limits. Zinc was the predominant metal in eggs, followed by copper and cadmium. Eggs from the Central region contained the most arsenic, cadmium, and chromium, while those from the West region had the highest nickel and mercury levels.

Combining the measured concentrations with the survey data, the researchers calculated estimated daily intakes for children aged 4 to 12, adolescents aged 13 to 20, adults aged 21 to 59, and people over 60. Exposure rose with consumption level in every age group and region, and it was consistently higher in children and adolescents than in adults and the elderly, because lower body weight amplifies intake per kilogram. The highest total estimated daily intake, roughly 1.2 micrograms per kilogram of body weight per day, occurred among high-consuming children in the West region, while adults generally stayed below 0.2 micrograms per kilogram per day. Notably, all estimated intakes remained below the provisional tolerable daily intake values set by international health authorities for each metal, meaning exposure from chicken and eggs alone falls within accepted limits.

The risk indices painted a more concerning picture. The target hazard quotient compares exposure to a reference dose, with values above 1 signaling potential non-carcinogenic effects. For children, mercury produced the highest quotients for chicken consumption, ranging from 27.8 to 1923.9, while cadmium dominated the egg-related risk. When all six metals were summed into a total target hazard quotient, or health risk index, the cumulative value exceeded 1 among high-consuming children and adolescents in all three regions, and among high-consuming elderly people in all regions as well as medium consumers in the Littoral and West regions. Adults were the exception: their individual and cumulative quotients stayed below 1, suggesting no significant non-carcinogenic risk from poultry consumption alone. Across the cumulative hazard, mercury accounted for about 50 percent of the total, followed by chromium at roughly 27 percent and cadmium at about 22 percent.

Carcinogenic risk was assessed through the incremental lifetime cancer risk, which estimates the probability of developing cancer over a lifetime from continuous exposure to carcinogenic metals, in this case lead, chromium, cadmium, arsenic, and nickel. Values below one in a million are considered negligible, between one in a million and one in ten thousand acceptable, and above one in ten thousand unacceptable. For most age groups and consumption categories, the cumulative risk fell within the acceptable range. For medium-consuming children in the Central region, the cumulative risk reached the upper boundary of one in ten thousand, the highest estimate in the study.

The authors emphasize that these findings do not mean poultry products in Cameroon are universally unsafe, but they do point to vulnerabilities that warrant attention. Children emerge as the most exposed group because of their lower body weight and higher intake relative to body mass, and the study’s conclusion notes that the health risk index exceeded 1 for children, adolescents, and elderly high consumers, while lifetime cancer risk values for nickel, arsenic, cadmium, and chromium exceeded the acceptable range in several groups. The researchers recommend strengthened monitoring of heavy metal contamination throughout the poultry production chain, stricter control of feed quality and environmental contamination sources, and effective food safety policies to reduce consumer exposure. They also caution that the study’s scope has limits: it covered three regions, a limited number of farms and composite samples, and estimated exposure from chicken and eggs alone, while people are simultaneously exposed to heavy metals from other foods, drinking water, and the environment, which could push cumulative lifetime exposure higher than these estimates suggest.

Subject of Research: Health risk assessment of heavy metal contamination in chicken meat and eggs from poultry farms in Cameroon

Article Title: Assessment of the health risks associated with the consumption of chicken meat and eggs contaminated with heavy metals in some regions of Cameroon

Article References: Keutchatang, F. D. P. T., Fokou, E., Mouafo, H. T., Nama, G. M., & Kansci, G. (2026). Assessment of the health risks associated with the consumption of chicken meat and eggs contaminated with heavy metals in some regions of Cameroon. Food Safety and Risk, 13(1), Article 36. https://doi.org/10.1186/s40550-026-00160-2

Image Credits: AI Generated

DOI: 10.1186/s40550-026-00160-2

Keywords: heavy metals, chicken meat, eggs, Cameroon, food safety, mercury, cadmium, health risk assessment, poultry, dietary exposure, ICP-OES, incremental lifetime cancer risk