Heavy Metal Intake Associated With Consumption Of Free Range Chicken Products In Kenya

Abstract

Enormous volumes of waste in form of water effluent, solid domestic waste or e-waste is generated in urban set up raising environmental concerns as they eventually end up in the food chain. Some of these are heavy metal contaminants which are common in peri-urban agriculture practices of free-range chicken that may lead to unsafe exposure to consumers yet limited information on the same exist in Kenyan scenario. The current study was carried out to determine the levels of heavy metals in free range chicken products and exposure of their consumers. A base line survey was carried out to assess the production and consumption of chicken products in the study area while heavy metals levels were determined by use of Atomic absorption spectroscopy. Consumption data and contamination were fit in @risk Palisade software to estimate exposure by chicken consumers in Embakasi area, exposure levels and distribution of heavy metals were determined with overall lead and copper in poultry exhibiting Laplace distribution, while cadmium and mercury had an exponential distribution. The consumption of free range chicken was found to be 78.1 % compared to exotic broilers (15.7 %) with more male consuming chicken (60.7 %) compared to the females (39.3 %). The muscle part of the chicken was found to have the highest preference (85.1 %), followed by gizzard at 4.5 %, liver at 1.7 % and other chicken parts at 2.5 %. The mean levels of all metals varied significantly (P<0.05) in the different chicken products. Average cadmium was found to be 0.04 ± 0.004 mg/kg in liver, 0.03 ± 0.004 mg/kg in muscle, 0.04 ± 0.01 mg/kg in gizzard and 0.04 ± 0.00 mg/kg in eggs. The level of lead was 0.26 ± 0.01 mg/kg in muscle, 0.28 ± 0.01 mg/kg in liver, 0.21 ± 0.02 mg/kg in gizzard and 0.04 ± 0.00 mg/kg in eggs. Copper levels were 0.52 ± 0.02 mg/kg in muscle, 0.79 ± 0.05 mg/kg in liver, 0.50 ± 0.03 mg/kg in gizzard and 0.53 mg/kg in eggs. Levels of mercury were 0.029 ± 0.01 mg/kg in liver, 0.027 ± 0.0293 mg/kg in muscle, 0.027 ± 0.00 mg/kg in gizzard and 0.0186 ± xvi 0.00 mg/kg in eggs. The mean cadmium levels in environmental samples were 0.715 ± 0.22 mg/kg in soil and 0.12 ± 0.10 mg/kg in vegetation; lead was 1.64 ± 0.55 mg/kg in soil, 0.205 ± 0.04 mg/kg in water and 0.21 ± 0.02 mg/kg in feed. Mercury levels were 0.55 ± 0.20 mg/kg in soil and was not detected in water. Copper was found to be < 3.28 ± 0.78 mg/kg in all samples. Dietary intake would not exceed levels of 0.004 mg/kgbw/day for mercury, 0.0025 mg/kgbw/month for cadmium, and 0.5 mg/kgbw/day for copper in free range chicken products. However, the safety levels were exceeded for lead which was 1.1 μg/kgbw/day at 95 percentiles against EFSA 0.5 μg/kgbw/day. In general, the risk of heavy metals was low except with lead in free range chicken products which indicated likelihood of high intake levels. This raises concerns in levels of lead in the environment necessitating the need for urgent interventions by agencies to check levels of lead in the environment