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

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 > 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

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

Microplastics distribution and characterization in epipsammic sediments of tropical Atlantic Ocean, Nigeria

regional data collection and environmental dynamics are vital aspects of understanding the underlying sources and factors that influence the abundance and dispersion of the plastic particles. This paper presents a baseline report on the abundance of microplastics across three tidal waterlines (high, drift and current) of the tropical Atlantic ecosystem. Microplastics (1 – 5 mm) occurrence and distribution in epipsammic sediments of five beaches in Lagos, Nigeria (Gulf of Guinea) were assessed. The microplastics were extracted by density flotation using saturated solution of NaCl and the identification of polymer types was done by attenuated total reflectance Fourier transform infra-red spectroscopy, ATR-FTIR. Results showed significant variations in the population of MPs in the three tidal waterlines with the high and drift waterlines accounting for 58.83% and 41.16% of the total MPs, respectively while no MPs were detected in the current waterline sediment. Polyethylene, polystyrene and polypropylene were the most abundant polymers recorded. Fragments were predominantly detected and preproduction pellets formed only 5.27% of total microplastics. Polymer risk index calculations showed low to medium risk of the microplastics found and local hydrodynamic conditions such as Ocean surges and current intensity were observed to influence the distribution and dispersion of microplastics. Continuous monitoring of MPs abundance is necessary to minimize the polymers’ risk to the ecosystem