RESUMEN

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.

RESUMEN

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.

RESUMEN

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.

RESUMEN

In this study concentration level of calcium, cadmium, copper, iron, magnesium, manganese, nickel, lead and zinc were determined in the amniotic fluid of pregnant women, aged 15 - 45 years enrolled at the Obafemi Awolowo University Teaching Hospitals Complex Ile - Ife. This was with a view to predict the body burden of the metals in the pregnant women and assess the health implications of the toxic elements to the pregnant women and their fetuses. Fifty samples of the amniotic fluid were collected from the pregnant women. The efficiency of extraction of trace metals using conventional wet acid digestion method (CDM) and microwave induced acid digestion method (MWD) was determined by recovery experiments. Levels of trace metals were determined using Atomic Absorption Spectrophotometry. The high percentage recoveries obtained from MWD made it a more efficient method than the CDM and hence its adoption for sample digestion. Statistical analysis of data using descriptive and inferential statistics revealed that age; education and profession have effects on the levels of the trace metals. The mean levels of most of the toxic metals obtained in this study were lower than the recommended limits of trace metals in women whole blood.

Asunto(s)

RESUMEN

This work centered on a 1-year evaluation campaign of point source pollution from a sewage treatment oxidation pond and its receiving stream. Water samples were collected from the sewage treatment oxidation pond and the receiving stream during July 2002 and June 2003. Concentrations of heavy metals were determined using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) after a triple acid digestion of samples using open beaker method. Generally, the results showed high levels of toxic metals such as Cd, Pb, As, Al, Cr, Mn, Co, and Fe in the influent and effluent samples as well as in the receiving stream. The annual mean concentration of metals in the sewage samples ranged from 11.90 to 16.05, 64.96 to 88.27, 38.91 to 76.35, 17.46 to 24.45 mug/L for Cd, As, Pb, Co, and 4.31 to 8.77, 1.71 to 2.45, 0.46 to 0.74 and 13.82 to 20.47 mg/l for Al, Cr, Mn and Fe, respectively; while in the receiving stream, the concentrations were between 6.89 to 10.45, 35.50 to 59.26, 22.85 to 35.94, 11.33 to 18.83 mug/l for Cd, As, Pb, Co, and 1.99 to 3.49, 1.35 to 2.08, 0.21 to 0.48, and 8.93 to 14.15 mg/l for Al, Cr, Mn and Fe, respectively. The discharge of the effluent from the sewage pond into the receiving stream has therefore led to increase in the concentrations of some heavy metals downstream, thus impacting the receiving stream negatively and could pose a serious health hazard to aquatic ecosystems and humans particularly for rural dwellers and peasant farmers downstream that utilize the water from the receiving stream for various domestic and agricultural purposes untreated.

Asunto(s)

RESUMEN

Africa as a continent has its unique challenges for analytical chemists in sample preparation for chromatographic analyses. The areas of agriculture, environment, food and health provide formidable challenges when it comes to method development, for example, drought can result in inadequate supplies of good quality water. The testing of water quality necessitates the development of assay methods that can be employed to not only determine the quantities of pesticides associated with malaria and tsetse fly eradication programmes, but also to monitor mycotoxins or neurotoxins. Urbanisation has also meant that endocrine disruptors such as phthalate esters need to be monitored. This review will profile some of the activities by analytical chemists practising in the African continent, who seek to address some of the challenges in sample preparation for chromatographic analyses.

Asunto(s)

RESUMEN

In this study, samples from a sewage treatment lagoon and those from a receiving stream were analyzed for their phthalate esters content. Knowledge of the distribution of ubiquitous phthalate esters in the sewage lagoon and the receiving stream was necessary because of the reports of their subtle toxicity to aquatic biota and humans. Liquid-liquid extraction, Clean-up experiment and High Performance Liquid Chromatography (HPLC) were the methods employed for the quantitative determination of the Phthalates. A study of uncontaminated water was done to establish blank levels. The sewage lagoon and the receiving stream were grossly polluted as several phthalate ester plasticizers: DMP, DEP, DPhP, DBP, DEHP, DOP and DINP were found present at monthly mean levels of between 24.02 mg/L and 139.25 mg/L in the sewage treatment lagoon and 10.41 mg/L and 80.53 mg/L in the receiving stream. The results showed higher levels of phthalate esters in the sewage lagoon compared to the receiving stream. The sewage lagoon was identified as a pollution point source into the receiving stream. Levels of phthalates obtained from the receiving stream are much higher than the water criteria of 3 microg/L phthalates recommended by the United States Environmental Protection Agency (USEPA) for the protection of fish and other aquatic life in water and the Suggested No-Adverse Effect Levels (SNAEL) of 7.5-38.5 microg/L for drinking water. This should give cause for great environmental concern. Peoples' health downstream is at stake and so is the 'health' of the ecosystem.

Asunto(s)

RESUMEN

Forty-one urine samples of smokers and non-smokers from Ile-Ife, Nigeria were analyzed for normal cadmium and lead levels after acid digestion. Results of the preliminary study show that concentrations of cadmium obtained were generally low compared with lead. The mean urinary levels from non-smokers ranged from 0.05 - 0.02 to 0.16 - 0.01 wg ml-1 and from 0.02 - 0.03 to 0.88 - 0.04 wg ml-1 for cadmium and lead respectively, whilst, for smokers, urinary levels varied between 0.07 - 0.01 and 0.23 - 0.02 wg ml-1 and between 0.28 - 0.03 and 1.02 - 0.02 wg ml-1 were obtained for cadmium and lead, respectively. Cd levels in urine of smokers and non-smokers are higher than the recommended normal level of 0.0085 wg ml-1, while levels of Pb are above the 0.08-0.15 wg ml-1 exposure range. Results of spiking experiments with urine gave high percentage recoveries for both elements (Cd, 87.9 - 0.40%) and (Pb, 90.40 - 0.12%). Blank determination was done for background correction.

Asunto(s)