Levels of polybrominated diphenyl ethers (PBDEs) in indoor dusts in Lagos and Ibadan, Nigeria

Abstract

Polybrominated diphenyl ethers (PBDEs) were analysed in dust samples collected from 10 homes, 10 cars, 10 offices and 10 schools in 2 different cities, Lagos and Ibadan, Nigeria. The daily dust ingestion was calculated for all the indoor microenvironment studied. Extraction of PBDEs was by ultrasonication and was analysed on a gas chromatography microelectron capture detector. This represents the first PBDE study in school dust on the African continent and also first PBDE study in Ibadan. Lagos is Africa’s most populated city and Ibadan is the third largest city in West Africa and of historical significance. The concentrations of ΣPBDEs (BDE 28, 47, 99,100,153,154,183 and 209) in homes, cars, offices and schools was 2.24–11500 ng/g; 1.20–258 ng/g; 3.76–687 ng/g and 0–471 ng/g, respectively. Generally, dust samples from Lagos had higher median concentration as compared to Ibadan. BDE-47, BDE-99 and BDE-183 were the most prominent congeners recorded. Interestingly, BDE-209 which is prevalent in dust samples in temperate region had a low concentration in this study (especially in car dust). This may be attributed to the photodegradation of BDE-209 due to Nigeria being a tropical country. samples in Lagos, very high median concentration levels of PBDE was present in-house dusts, with slightly lower PBDE levels recorded in office dust. BDE-100 and BDE-183 were the most prevalent congeners in school dust samples. The median concentration obtained was lower when compared to Australian schools. The concentrations of PBDE in house and office dusts in Nigeria was less than studies in the UK and US but similar to values from South Africa and Egypt. The daily intake of PBDEs from all indoor dust samples were below USEPA reference dose (RfD) for oral exposure for all BDE congeners. For all indoor dust categories, toddlers had the possibility for the highest ingestion rate, and this is of serious concern. Lastly, the method scaled analytical Eco-Scale evaluation and Green Analytical Chemical Procedure Index as “an acceptable green analysis method”.