Distribution of heavy metals in sediments of Igbede, Ojo and Ojora rivers of Lagos, Nigeria

The distribution of some heavy metals, namely Cd, Pb, Zn, Fe, Cu, Cr and Mn in epipellic sediments of Igbede, Ojo and Ojora rivers of Lagos was studied weekly in the early summer (November) of 2003. The levels of selected trace metals were determined using Atomic Absorption Spectrophotometer (UNICAM 969 AAS SOLAR). Trends in heavy metal burdens in the sediments revealed weekly variations in all the rivers assessed. Statistical analyses also showed different mean levels of trace metals in the aquatic environments, the distribution of which followed the sequence Fe > Zn > Mn > Pb > Cu > Cr > Cd, Fe > Zn > Cu > Mn > Pb > Cr > Cd and Fe > Zn > Mn > Cu > Cr > Pb > Cd in Igbede, Ojo and Ojora rivers respectively. Fe recorded the highest concentration levels (1,582.95 ± 96.57 μg/g–1,910.34 ± 723.19 μg/g) in all the sediments investigated while the Cd levels (0.06 ± 0.10 μg/g–0.47 ± 0.36 μg/g) were the lowest. Expectedly, trace metal concentrations in fine grain muddy sediments of the Igbede and Ojo coastline were much higher than those of Ojora which consist of coarse and sandy deposits covering the near shore area. Generally, the results obtained fell within toler-able limits stipulated by World Health Organization (WHO)

ORGANOCHLORINES IN CHRYSICHTHYS NIGRODIGITATUS AND LIZA GRANDISQUAMIS FROM LAGOS LAGOON AND AGBOYI CREEK, NIGERIA

Catfish (Chrysichthys nigrodigitatus) and mullet (Liza grandisquamis) were sampled from Lagos Lagoon and Agboyi Creek and analysed for alpha-BHC, beta-BHC, lindane, delta-BHC, heptachlor, heptachlorepoxide (B), aldrin, dieldrin, endrin, endrin aldehyde, endrin ketone, cis-chlordane, trans-chlordane, endosulfan 1, endosulfan 11, endosulfan sulphate, methoxychlor, p,p´-DDE, p,p´-DDD and p,p´-DDT. Sampling was conducted four times at the designated sites during the dry season months of December 2008 and February 2009 and the wet season months of May and September 2009. The muscle tissues and organs of the finfishes were subjected to cold extraction with petroleum ether/acetone (1:1 v/v) mixture and clean-up on silica gel adsorbents. A gas chromatograph coupled with electron capture detector (GC-ECD) was used to detect and determine the organochlorines. The residue levels of the fishes were higher in the Lagos Lagoon than in Agboyi Creek while a higher concentration of the residues was observed during the dry season. The female fishes accumulated higher organochlorines than the male fishes. The order of residue accumulation in the organs of the fishes was gills > livers > large intestines > small intestines > kidneys > muscles. The dietary surveys indicated that the amount of fishes consumed ranged from 20 to 200 g/day, with a mean value of 40 g/day. The estimated daily intakes of the organochlorines were within the acceptable daily intakes while the levels of residues in the fishes were within the permissible residue limits

Bioaccumulation of heavy metals in frequently consumed leafy vegetable grown along Nigeria-Benin Seme Border, West Africa

Vegetable growing along major highways with heavy vehicular movement has been a serious concern to food safety specialist in large cities. The contributions of heavy metals in selected vegetables through atmospheric deposition were quantified using atomic absorption spectrophotometer. The level of some heavy metal (.Pb, Cu, Fe, and Cr) were examined in the edible portion of Telfciria occidentals, Corchorus olitorius, Celocia argentea, and Thymus Vulgaries, grown along Nigeria-Republic of Benin border Seme. The results showed that the levels of heavy metal ranged from 21.69 ± 7.36 μg/g Cu to172.87 ±62.05 μg/g Fe in Telfaria occidentalis, 21.74±13.00 μg/g Pb to 304.50±72.77 μg/g Fe in Corchorus olitorius, 16.75±10.54 μg/g Pb to 260.74±215.37 μg/g Fe in Celocia argentea and 23.53±3.52 μg/g Cu to 406.33±225.06 μg/g Fe in Thymus Vulgaries were recorded in site A. The value heavy metal contamination obtained from site B ranged from 18.91±11.98 μg/g Pb to 166.49 ± 86.22 μg/g Fe in Telfaria occidentalis, 16.57± 9.22 μg/g Pb to 292.36±196.33 μg/g Fe in Corchorus olitorius, 19.99±8.54 μg/g Pb to 354.03±302.80 Fe in Celocia argentea and 21.73±8.44 μg/g Pb to 388.20±226.39 μg/g Fe in Thymus Vulgaries. The order of contamination in the vegetable sample was Fe > Cr > Cu > Pb. The data were analyzed with t-test and ANOVA. There were no significant different between the (p< .05) between the level of heavy metal in vegetable at each sampling site. The high levels of metal in the sampled vegetable may be attributed to excessive application of fertilizers and other agro chemical, as well the use of use of waste water for washing the vegetables. The obtained results were higher than the threshold value of WHO, FEPA and China stipulated standards for mature plant tissue except for copper in all the analyzed vegetable. Therefore, the consumption of these vegetables as food may pose possible health hazards to human

Distribution of heavy metals in sediments of Igbede, Ojo and Ojora rivers of Lagos, Nigeria

Abstract The distribution of some heavy metals, namely Cd, Pb, Zn, Fe, Cu, Cr and Mn in epipellic sediments of Igbede, Ojo and Ojora rivers of Lagos was studied weekly in the early summer (November) of 2003. The levels of selected trace metals were determined using Atomic Absorption Spectrophotometer (UNICAM 969 AAS SOLAR). Trends in heavy metal burdens in the sediments revealed weekly variations in all the rivers assessed. Statistical analyses also showed different mean levels of trace metals in the aquatic environments, the distribution of which followed the sequence Fe &gt; Zn &gt; Mn &gt; Pb &gt; Cu &gt; Cr &gt; Cd, Fe &gt; Zn &gt; Cu &gt; Mn &gt; Pb &gt; Cr &gt; Cd and Fe &gt; Zn &gt; Mn &gt; Cu &gt; Cr &gt; Pb &gt; Cd in Igbede, Ojo and Ojora rivers respectively. Fe recorded the highest concentration levels (1,582.95 ± 96.57 μg/g-1,910.34 ± 723.19 μg/g) in all the sediments investigated while the Cd levels (0.06 ± 0.10 μg/g-0.47 ± 0.36 μg/g) were the lowest. Expectedly, trace metal concentrations in fine grain muddy sediments of the Igbede and Ojo coastline were much higher than those of Ojora which consist of coarse and sandy deposits covering the near shore area. Generally, the results obtained fell within toler

Dataset on microplastics and associated trace metals and phthalate esters in sandy beaches of tropical Atlantic ecosystems, Nigeria

This article presents data on the occurrence and distribution of phthalate esters and metals associated with microplastics (MPs) (1–5 mm) collected from four beaches in the trop- ical Atlantic ecosystems, Nigeria, Gulf of Guinea. Informa- tion on microplastics extraction by density flotation with saturated NaCl and polymer identification with attenuated total reflectance infra-red spectroscopy (ATR-FTIR) is also provided. Analysis of six phthalate esters (PAEs) (dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DnBP), benzyl butyl phthalate (BBP), di (ethyl hexyl) phtha- late (DEHP), and di n-octyl phthalate (DnOP)) associated with the microplastics by performed using Gas chromatography–mass spectroscopy (GC–MS). Metals including Ag, Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Si, Sr, Ti, Tl, V, and Zn were analysed by inductively cou- pled plasma–optical emission spectrometry (ICP–OES). The data present the separation of microplastics from sediment, extraction with cyclohexane/ethyl acetate (1:1, v/v) and 10% HNO 3 for phthalate esters and metals, respectively, and the determination of target analytes concentrations. The compo- sitional distributions of MPs and levels of carcinogenic and toxic metals and phthalate esters are presented. The dataset could be used for the evaluation of ecological risk associated with PAEs in the marine ecosystems

Toxic metals in cigarettes and human health risk assessment associated with inhalation exposure

This study evaluated the concentrations of cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), lead (Pb), and zinc (Zn) in 10 branded cigarettes commonly consumed in Nigeria. Chemical sequential extraction method and pseudo-total metal digestion procedure were used for extraction of metals from filler tobacco and filter samples. Samples were analyzed using flame atomic absorption spectrometry (FAAS). The filler tobacco of cigarettes had Cd, Cu, Fe, Mn, Pb, and Zn concentrations in the ranges of 5.90–7.94, 18.26–34.94, 192.61–3494.05, 44.67–297.69, 17.21–74.78, and 47.02–167.31 μg/cigarette, respectively. The minimum and maximum concentrations in the filter samples were 8.67–12.34 μg/g of Cd, 1.77–36.48 μg/g of Cu, 1.83–15.27 μg/g of Fe, 3.82–7.44 μg/g of Mn, 4.09–13.78 μg/g of Pb, and 30.07–46.70 μg/g of Zn. The results of this study showed that the concentrations of heavy metals in the filler tobacco samples were consistently higher than those obtained for the cigarette filters except for Cd. Toxic metals were largely found in the most labile chemical fractions. Moderate to very high risks are found associated with potential exposure to Cd and Pb. The carcinogenic risks posed by Cd and Pb ranged between 1.87E-02 and 2.52E-02, 1.05E-03 and 4.76E-03, respectively, while the non-carcinogenic risk estimates for Cd and Pb were greater than 1.0 (HI > 1). Toxic metals in cigarette may have significant carcinogenic and non-carcinogenic health effects associated with inhalation exposure. Continuous monitoring and regulations of the ingredients of imported and locally produced tobacco products are advocated