Moreover, neither the study area nor its immediate upstream section is being explored for mining activities or exposed to industrial activities, to suggest high concentrations of metals like Cd, Pb, Hg or Ni in the basin. Towards bridging this information gap, Cu and Zn were selected for the study in view of the fact that they have been ranked top in terms of toxicity among eight heavy metals (i.e. In spite of the regional and global significance of this section of Osun River as a WHS, there has been no toxicological or biomonitoring study conducted therein. Furthermore, if biodiversity/natural value of the WHS must be conserved, it is very important to monitor the health status of its river system. Motivation for this study was born out of the fact that life, both in the riparian and freshwater systems of the WHS, will depend to a large extent on the health status of the river system therein. The site, though selected as a WHS based on cultural values, has recently been described as a biodiversity hotspot for plants and some animal groups (Akinpelu and Areo 2007 Onyekwelu and Olusola 2014). Cu and Zn) in the river system which drains the Osun-Osogbo Sacred Grove, a UNESCO World Heritage Site (WHS). Thus, this study seeks to assess the level of two PBTs (i.e. Melanoides tuberculata Müller and Lanistes varicus Müller) have been reported as keystone species among invertebrate assemblage of the river system (Akindele et al. In the UNESCO-protected environment of Osun River, two gastropod species (i.e. Consequently, the organisms themselves become toxic (Ray and McCormick-Ray 2014). Through feeding, such toxicants concentrate in their fatty tissues and overtime the body-load can reach a concentration greater than ambient water. Studies have shown that uptake of heavy metals by the aquatic organisms is either via semi-permeable body surface or gut (Rainbow 2007). PBTs persist in aquatic environments owing to their resistance to physical, chemical and metabolic breakdown and consequent accumulation in sediments where organisms feed. They include the heavy metals and organo-metal compounds. Persistent bioaccumulative toxicants (PBTs) are ubiquitous despite bans or regulated use and are highly toxic and extremely persistent in aquatic environments (Muir and de Wit 2010 Ray and McCormick-Ray 2014). Concentrations of both metals in the sediments as well as their accumulation factors in both gastropod species were indicative of an unimpacted freshwater system. Conclusionsįindings from this study suggest that both metals posed no toxicological risk to the freshwater system of Osun River. varicus recorded higher bioaccumulation factor than M. Both metals recorded much lower values than their average concentrations in the Earth’s crust as well as the recommended limits for freshwater life. In the same vein, Cu was significantly lower ( p < 0.01) than Zn in both species. With the exception of September sampling period, the two metals recorded higher values in the animals than in the sediments. Dry samples were digested and analysed for Cu and Zn using the atomic absorption spectrophotometry. Benthic sediment and gastropod samples were collected on quarterly basis from June 2015 to March 2016 along the longitudinal stretch of the river. In this study, we investigated the concentrations of Cu and Zn in the benthic sediments and two dominant gastropod species ( Melanoides tuberculata and Lanistes varicus) of the Osun River. The 36 States & Federal Capital Territory (FCT) plus their respective primary postal codes within them are listed below.Osun River dissecting the Osun-Osogbo Sacred Grove, though inscribed on the World Heritage List, has been rarely assessed for biodiversity values or ecotoxicology. Video: Nigeria Postal Codes States North Central See below all the States of Nigeria, their Local Government Areas, and Zip Codes. Map of Nigeria showing the 36 states and Federal Capital Territory Unlike what most people think, Nigeria zip code is well organized by the Nigerian Postal Service, the country is divided into nine regions, and each region code makes up the first digit. The NIPOST divides the country into 9 regions, and those regions determine the first digit of the 6-digit code while the last 3 digits at the end of the code is determined by your local post office. Unlike some countries where postal/zip codes usually carry some alphabet, Nigeria Postal codes are represented using only 6 digits, irrespective of the region. The Nigerian Postal Service ( NIPOST) has a chronological arrangement of the Nigeria postal codes of various cities and regions in the country.
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