Polybrominated diphenyl ethers (PBDEs) concentrations in soil and plants around municipal dumpsites in Abuja, Nigeria.

Polybrominated diphenyl ethers (PBDEs) are listed as persistent organic pollutants (POPs) in the Stockholm Convention. It has been established that PBDEs may be released into the environment during improper handling and disposal of e-waste and other products containing PBDEs that is prevalent in developing countries. This research work assessed the status of PBDE contamination at dumpsites in Nigeria. Soil and edible plant samples were collected from the dumpsites and control sites for analysis. The concentrations of ∑7PBDE in the topsoils around the dumpsites at 0-15 cm depth ranged from 112 to 366 ng/g dry weight (dw) while that of the topsoil of the control site 500 m from the dumpsite ranged from 26.8 to 39.7 ng/g dw. These high concentrations stem likely from open burning of waste including electronic waste on the landfills. Plant samples (bentgrass, spinach, tomatoes, pumpkin and sweet potatoes) around the dumpsites were found to be contaminated by PBDEs with levels ranging from 25.0 to 60.5 ng/g dw in plant roots and from 8.45 to 32.2 ng/g dw in plant shoots for ∑7PBDE. This suggests that consumption of vegetables by humans and ingestion of contaminated soils and feed by chickens and cows can transfer PBDEs into the human food chain around the dumpsites. The comparison of PBDE levels in soils and the PBDE levels in chicken eggs from the former study indicate that PBDE levels in the soils are sufficient to explain the levels in the chicken eggs with a reasonable carry-over rate for PBDEs of 0.28 on average. The PBDE contamination in the soil was sufficient to result in a relevant exposure of humans via accumulation in eggs. The study shows that a better management of end-of-life products containing PBDEs is needed to reduce PBDE exposure risk in Africa.

Polybrominated diphenyl ethers (PBDEs) in chicken eggs and cow milk around municipal dumpsites in Abuja, Nigeria.

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in electronic equipment, as polymers in vehicles or construction, and in textiles. These additive flame retardants are emerging pollutants in Africa, released by the non-environmentally sound disposal of consumer products, often imported as secondhand, that have increasingly reached their end-of-life in the last decade. In Nigeria, which is a major receiver of e-waste and secondhand cars, there is a dearth of information regarding the levels of PBDEs in the environment, biota, and food. Thus, this study was designed to investigate the PBDE contamination of food samples of animal origin (chicken eggs and cow milk) around municipal waste dumpsites and background areas in Nigeria, to elucidate the role of dumpsites as potential sources of PBDE pollution and exposure in the country. Biological samples were collected over two years from two municipal waste dumpsites in Abuja. Fifty-six samples each of free-range chicken eggs and cow milk were collected. Control samples were collected approximately 5 km away from the dumpsites. After extraction and clean-up, the levels of POP-PBDEs listed in 2009 (major congeners of tetraBDE to heptaBDE), plus BDE-28 (Σ7PBDEs) were determined using GC-ECD. Data were analysed using descriptive statistics, t-test at α0.05. Levels of Σ7PBDEs (ng/g lipid weight (lw)) in chicken eggs at the two study sites ranged from 262.3 to 313.4 (ng/g lw), more than one order of magnitude higher than those at the control site in a village near the dumpsites (14.9 ±â€¯3.73 ng/g lw), and two and more orders of magnitude higher compared to PBDE levels in these products in industrial countries and Nigerian supermarkets. Median PBDE levels in cow milk from the two dumpsites were 49.1 and 81.5 ng/g lw, respectively, considerably higher than levels in other studies. Proper disposal methods of waste polymers containing PBDEs such as co-incineration in BAT cement kilns and plastic recycling with separation is urgently needed in Nigeria and other parts of Africa, to prevent open burning as well as crude recycle to reduce PBDE levels in the environment and human food.