Speciation of Trace Metals Pb, Zn, Cu and Cd in Surficial Sediment from Makupa Creek Mombasa, Coastal Kenya

Abstract

Trace metals (Zn, Pb, Cu, Cd) speciation of surface sediments from Makupa creek, coastal Kenya were determined by sequential extraction procedure. The procedure was used to extract the trace metals in sediments geochemical phases (exchangeable, carbonates, Fe-Mn oxides, organic matter/sulphide, and residual). Trace metals analysis was done using ICP/MS. The trace metal speciation results indicated that Pb, Zn, and Cd were mainly associated with the exchangeable, carbonates and Fe-Mn oxides in most of the sampling sites. The highest concentration of the trace metals were associated with Fe-Mn oxides with Zn concentration at 362.5 µg/g, Pb, 31.5 µg/g. Copper was mostly associated with the organic matter/sulphide and carbonate at concentration of 117.5 µg/g and 69.9 µg/g respectively. Generally, trace metals in sediment from Makupa creek were mainly associated with the bioavailable fractions (BAF) and their ranges were: Pb (60%-98%), Zn (90%-99%), Cu (70%-91%). It was found therefore, that there was trace metals enrichment in sediments from Makupa from anthropogenic sources and bioavailable to biota.

Determination of Some Selected Heavy Metals in Effluents from Lubricants Manufacturing and Associated Contamination of Oysters (Crassostrea cucullata) and Soil near Discharge Points in Mombasa, Kenya

“…This is in line with a research report by Kinuthia and his colleagues (2020) which explained that contaminated waste water can lead to a build-up of heavy metals in soils (4) . Similar results were reported by Ann et al (2003) (2) , Philip et al (2016) (11) and Mwatsahu et al (2020) (14 ) where heavy metals were detected in the soils samples and fauna samples from Makupa and Port-Reitz creeks.…”

Microplastic pollution in the surface waters of creeks along the Kenyan coast, Western Indian Ocean (WIO)

“…The region experiences fairly high average temperatures ranging between 26 and 32 0 C, with a small diurnal range of between 7 and 9 0 C (Obeiro and Onyando, 2013). The creeks are subjected to semi-diurnal patterns of tides averaging between 0.6 and 1.0 m during neap tide and 2.5 and 4.5 m during spring tide (Nguli et al, 2006 (Maritim et al, 2016). Rapid urbanization and high population growth have led to the development of informal settlements around the Coast General Hospital and Kenya Meat Commission near Tudor Creek (Okuku et al, 2011).…”

Microplastic Polymers in Surface Waters and Sediments in the Creeks Along the Kenya Coast, Western Indian Ocean (WIO)

“…An estimated 0.9 m 3 s -1 of water is discharged into the creek, with the highest discharge occurring between April and June at 1.8 m 3 s -1 (Wakwabi and Mees, 1999). The creek is surrounded by populated informal settlements and villages such as Mushomoroni, Mikindani, Coast General Hospital, and Kenya Meat Commission as a result of rapid urbanisation that has driven the need for labour force in the manufacturing industries, service industries, and the Port of Mombasa (Maritim et al, 2016;Okuku et al, 2011). The inner basin is fringed by mangrove forests, mainly Rhizophora mucronata and Avicennia marina and mudflats (Mirriam, 2010;Nguli et al, 2006;Owuor et al, 2019).…”

“…Mwache river discharges 215million m 3 of water annually, equivalent to 6.2 m 3 s -1 (UNEP, 1998). The creek is surrounded by highly populated villages such as Dongo Kaya, Dunga Nusa, and Ngala (Maritim et al, 2016;Okuku et al, 2011), Shimanzi, Makunde, and Kibarani (Kamau, 2002). The creek has heavy human activities ranging from the settlement, industrial (kipevu power generation station, Kenya ports authority, and heavy commercial transport deports) to municipal waste dumping site (Kibarani dumpsite).…”