Bisphenol-A (BPA) in Foods commonly consumed in Southwest Nigeria and its Human Health Risk.

Bisphenol-A (BPA) is a synthetic chemical ubiquitous in the environment and listed as an endocrine disruptor. It has the tendency of migrating into food stored in materials containing it. This study, therefore, determines the concentrations of BPA in foods commonly consumed in Southwest Nigeria by the adult population and also estimates the risk associated with human exposure. Eight different food categories were selected for this study. Standard QuEChERS protocol was used for sample extraction and analysed using gas chromatography-mass spectrometry (GC-MS). Vegetable oil had the highest BPA concentration (28.4 ng/g). This was followed by aquatic canned fish (26.3 ng/g), canned beef (21.3 ng/g) and crayfish (17.5 ng/g). These concentrations were below the 600 ng/g limit of the European Commission for BPA in foods. Bisphenol-A was not detected in raw beef, chicken, cheese, apple, tomatoes, beans and rice; and chicken eggs. The adult population had an average dietary intake of 30.4 ng/kg bw/day. There is no likely occurrence of harmful health effects of BPA in the selected foods with respect to the current concentrations found therein. However, routine monitoring is recommended to prevent human exposure to BPA.

Ecological Risk and Human Health Implications of Heavy Metals Contamination of Surface Soil in E-Waste Recycling Sites in Douala, Cameroun.

BACKGROUND: Recycling of electronic waste (e-waste) in developing nations poses a risk to the environment and human health through the release of heavy metals. OBJECTIVES: The aim of the present study was to evaluate the levels of heavy metals in Douala, Cameroun, the site of e-waste recycling activities. METHODS: Soil samples were collected from Makea, Ngodi and New Bell e-waste recycling sites, as well as from a control site. Samples were digested and levels of heavy metals were determined. RESULTS: The concentrations of the heavy metals in Makea occurred in the order of lead (Pb) (290±40) > zinc (Zn) (160±30) > chromium (Cr) (130±40) > copper (Cu) (130±20) > nickel (Ni) (56±5.7) > cadmium (Cd) (20±3.0); Pb (310±30) >Zn (150±20) >Cu (80±30) >Cr (70±40) >Ni (50±1.0) >Cd (30±5.0) in Ngodi; and Pb (280±40) >Zn (155±35) >Cu (80±50) >Cr (70±40) >Ni (53±2.0) >Cd (20±10) in New Bell. The levels of metals in all of the samples were higher compared to the control site, which was composed of vegetation and far from the e-waste sites, and in some cases, higher than permissible limits or guidelines. The ecological risk index of heavy metals for soil samples in all the e-waste sites indicated a very high risk. CONCLUSIONS: Heavy metals concentrations in soil around e-waste recycling sites present serious health risks and further investigations are needed. COMPETING INTERESTS: The authors declare no competing financial interests.

Lead and Cadmium Levels in Residential Soils of Lagos and Ibadan, Nigeria.

BACKGROUND: Lead and cadmium are components of paints sold in Nigeria. These heavy metals are associated with adverse neurological, cardiovascular and other human health effects. OBJECTIVES: This study assesses the levels of lead and cadmium in topsoil of residential areas in Lagos and Ibadan potentially resulting from painting of buildings. METHODS: Samples were pre-treated prior to metal determination using atomic absorption spectrophotometry. Metal speciation was determined using modified Tessier sequential extraction. Soil characteristics were determined by standard methods. Soil contamination was assessed using contamination factor, geo-accumulation and pollution load indices. The United States Environmental Protection Agency integrated exposure uptake biokinetic (IEUBK) model was used to estimate and predict children's blood lead levels (BLL). RESULTS: Lead and cadmium concentrations in residential areas in Lagos and Ibadan ranged from 1.56-419 mg/kg and not detected-2.8 mg/kg, respectively. Metal contamination factor and pollution load index were highest at the Lagos low income settlement. Results of IEUBK modelling showed that the Lagos low income settlement had the highest probability density for children between 1-7 years of age with an estimated BLL of >10 µg/dL. This population made up less than 0.01% of those within this age range. CONCLUSIONS: Lead and cadmium concentrations in soil around the residential buildings were higher than those in the control sample. Contamination factor and pollution load index showed significant contamination in average and low income settlements. These results suggested that there was accumulation of the metals in the soil, which can persist in the environment. This may pose serious health risks, especially to vulnerable groups such as children.