Evaluation of physicochemical properties and heavy metal speciation of groundwater in Ifetedo and Garage Olode, Osun State, Nigeria.

To a large extent, public health can be prevented from being compromised by having access to potable water whose physicochemical fingerprints conform to the WHO Guidelines for drinking water. This study was carried out to assess the physicochemical properties and heavy metals speciation of groundwater in Nigeria. Water samples from thirteen sites were collected for three months and analysed for levels of pH, conductivity, nitrate, sulphate, phosphate, and heavy metals using standard methods. The results of the analysis revealed that the respective mean temperature, conductivity, pH, total dissolved solids, and oxygen reduction potential of Ifetedo sites were 27.57 ± 0.66 °C, 318.93 ± 108.58 µS/cm, 5.29 ± 0.20, 207.40 ± 73.58 mg/L, and 265.17 ± 11.29 mV, while those of Garage Olode were 28.53 °C, 275.04 ± 133.75 µS/cm, 5.23 ± 0.04, 177.66 ± 89.37 mg/L, and 270.43 ± 37.75 mV. Total mean levels (µg/mL) of heavy metals ranged from 0.04 ± 0.01 Cd to 26.21 ± 3.63 Mn at Ifetedo, while at Garage Olode, the range was between 0.02 ± 0.00 Cd and 14.49 ± 5.70 Mn. The respective ranges of mean values (µg/mL) of exchangeable metals were 0.01 ± 0.00 Cd to 10.64 ± 1.20 Mn and 0.01 ± 0.00 to 7.53 ± 2.57 Mn at Ifetedo and Garage Olode. Going by WHO provision for drinking water, the study concluded that the levels of heavy metals in the potable water samples could constitute serious health hazards over prolonged usage unless some water treatment protocols are adopted.

Human health risk assessments of organochlorine pesticides in some food crops from Esa-Oke farm settlement, Osun State, Nigeria.

Seasonal levels of organochlorine pesticides (OCPs) in yam, cassava, sweet potato and cocoyam samples collected from Esa-Oke Farm Settlement, Osun State, Nigeria were evaluated. Sampling regiment for three sites lasted four months each during the dry and wet seasons. The dried samples were extracted using Soxhlet extractor with dichloromethane (DCM) as the extraction solvent, while the identification and estimation of OCPs in the crop filtrates, after clean-up, were carried out with Gas Chromatography equipped with Time-of-Flight Mass Spectroscopy Detector (GC-TOFMS). Ten OCPs determined in the crops had the overall seasonal mean levels that ranged from 158 ng/g (dieldrin) to 544 ng/g (heptachlor) and the seasonal mean burden per OCP occurred in the order: heptachlor epoxide (518) > heptachlor (447) > p,p'-DDE (431) > dieldrin (349) > chlordane (327) > aldrin (321) > p,p'-DDD (313) > methoxychlor (303) > endosulfan I (287) > p,p'-DDT (284) for wet season while this order was not the same for dry season of the same crop with heptachlor epoxide (415) > p,p'-DDE (373) > aldrin (305) > heptachlor (307) > methoxychlor (288) > chlordane (274) > p,p'-DDT (263) > p,p'-DDD (263) > endosulfan I (260) > dieldrin (246). For all of the OCPs, the estimated daily intake (EDI) and health risk indices (HRI) were significantly higher than the recommended values. Thus, a regular large-scale consumption of crop products from the farm settlement could result in grave public health concern in the course of time.

Determination of polycyclic aromatic hydrocarbons and potentially toxic metals in commonly consumed beef sausage roll products in Nigeria.

Levels of polycyclic aromatic hydrocarbons (PAHs) and potentially toxic metals (PTMs) were determined in the commonly consumed beef sausage roll products (coded BS1 - BS6) in Nigeria. This was done in order to assess the safety of regular consumption of these products with respect to the substances determined. Three batches of six samples of beef sausage roll products were collected from Ile-Ife, Osun sate, Nigeria. A part of the pretreated sample was Soxhlet extracted using n-hexane and analyzed with Gas Chromatography coupled with Flame Ionization Detector (GC-FID) to identify and quantify each of the PAHs in the sample, while Atomic Absorption Spectrometer (AAS) was used to profile the concentrations of As, Cd, Co, Cu, Pd, Mn and Zn in the digested sausage roll samples. Levels of PAHs in the samples ranged from 1.84 µg/g of Acenaphthylene in BS5 to 282.83 µg/g of Benzo[k]fluoranthene in BS1. Concentrations of benzo[a]pyrene in all the samples were higher than the guideline value of 0.003 mg/kg/day. For PTMs, a range of 0.075 µg/g As in both BS1 and BS6 to 2.950 µg/g Cu in BS3 was obtained. The study concluded that both PAHs and PTMs occurred in the samples at levels that called for caution on the part of consumers to prevent health infarctions that might be associated with prolonged regular and large consumption of beef sausage roll products.

Organochlorine pesticide residues in dried cocoa beans obtained from cocoa stores at Ondo and Ile-Ife, Southwestern Nigeria.

Levels of organochlorine pesticides (OCPs) were determined in dried cocoa beans obtained from cocoa produce stores at Ondo and Ile-Ife, Southwestern Nigeria. Cocoa beans samples were sun dried to a constant weight, pulverized and soxhlet extracted with dichloromethane to obtain the OCPs. Qualitative identification and quantitative evaluation of the extracted OCPs after clean-up on silica gel were accomplished with the aid of a Gas Chromatography coupled with an Electron Capture Detector (GC-ECD). Levels of OCPs in cocoa beans from Ondo had a mean range of ND (p, p'-DDE) to 82.17 ± 54.53 ng/g (p, p'-DDT) were higher than the OCPs levels in cocoa beans from Ile-Ife with a mean range of 0.37 ± 0.63 ng/g (Endrin) to 57.76 ± 81.48 ng/g (p, p'-DDT). The higher levels of OCPs detected in the cocoa beans from Ondo could be an indication of higher volume of OCPs application by cocoa farmers in Ondo and its environs since cocoa plantations were more concentrated than Ile-Ife environs. Levels of OCPs determined in the cocoa beans were within the Maximum Residue Limit (MRLs) for OCPs set by the World Health Organization/Food and Agricultural Organization. The study established the presence of OCPs in an important crop of Nigeria. Hence, there is the need to keep monitoring ecotoxicological chemical substances in agricultural food products of Nigeria so as to take steps that ensure health safety of end users.

Bromate and trace metal levels in bread loaves from outlets within Ile-Ife Metropolis, Southwestern Nigeria.

Bread loaves randomly sampled from nine outlets and bakeries within Ile-Ife were analysed to determine their safety levels for human consumption with respect to bromate and trace metal contents. Bromate determination was carried out via spectrophotometric method while trace metals in the digested bread samples were profiled using Flame Atomic Absorption Spectrophotometer. Bromate levels in the analyzed bread samples ranged from 2.051 ± 0.011 µg/g to 66.224 ± 0.014 µg/g while the trace metal levels were of the order: 0.03-0.10 µg/g Co = 0.03-0.10 µg/g Pb < 0.23-0.46 µg/g Cu < 2.23-6.63 µg/g Zn < 25.83-75.53 µg/g Mn. This study revealed that many bread bakers around Ile-Ife had not fully complied with the bromate-free rule stipulated by NAFDAC contrary to the "bromate free" inscribed on the labels of the bread. The bread samples contained both essential and toxic trace metals to levels that could threaten the health of consumers over prolonged regular consumption.

Heavy metal exposure from personal care products.

Numerous studies have described human exposure to heavy metals from diverse sources in Nigeria, but little is known about the exposure from personal care products, and few or no report is available on the personal care product concentrations of cadmium, chromium, copper and zinc, which have biotic effects. The levels of these elements were determined in 74 samples of 5 different classes of personal care products commonly used in Nigeria using atomic absorption spectrophotometry. Significant levels of Cd, Cr, Cu and Zn were found in all the products. The highest values of Cd (0.553 ppm) and Cu (0.783 ppm) were observed in hair cream, while medicated cream was mostly implicated for Cr (0.383 ppm) and Zn (0.793 ppm). Since no limit relating to cosmetic products is available, it is difficult to ascertain if the values of metals obtained in this study are too high or low; but Cd and Cr are prohibited in any amount in cosmetics. Prolonged use of soaps and creams containing these elements may pose threat to human health and the environment.

Changes in Testes Lipid Profile in Rats Fed on Thermally-Oxidized Soya bean Oil-Based Diets

The effect of thermally-oxidized soyabean oil-based diets on the lipid profile of the testes of rats was studied. For 35 days; two groups of male weanling rats were fed a basal diet containing unoxidised and oxidized soyabean oil. Rats fed the thermally oxidized soyabean oil diets displayed typical signs of essential fatty acids (EFA) deficiency and had their testes weights reduced to about 81 of fats fed unoxidised soyabean oil diets. There was a significant decrease (p0.05) in phosphatidylcholine and diphosphatidylglycerol content and increase in cholesterol (p0.005) content of the testes of rats fed oxidized soyabean oil-based diet compared to those fed unoxidised oil diets