JASEM ISSN 1119-8362 Full-text Available Online at J. Appl. Sci. Environ. Manage. March., 2016 JAllO UrightsRN AreservedL OF APPLIED S www.ajol.infoCIENCE A NandD ENVIRONVol.ME N20T (A1L) 25M –A 31NA GEMENT. www.bioline.org.br/ja Monitoring of specific activities of long-lived radioactive elements along the Mini- Okoro/Oginigba Creek, Port Harcourt 1GREGORY O. AVWIRI, 2*OLANREWAJU LAWAL, 1EDITH I. NWOKEOJI 1Department of Physics, Faculty of Science, University of Port Harcourt, Port Harcourt, Rivers State 2Department of Geography and Environmental Management, Faculty of Social Sciences, University of Port Harcourt, Port Harcourt, Rivers State *Corresponding author’s contact: Tel.: +2349097347063; Email: [email protected] ABSTRACT: Presence and concentrations of radionuclides could be as a result of natural and human activities. This study examined the associations and differences among soil, sediment and water specific activities of long-lived radioactive element (LLRE). Gamma spectroscopy was used to measure the concentration of the LLRE along the Mini Okoro/Oginigba Creek, Port Harcourt. Specific activities of three selected LLRE were derived. Correlation analysis was carried out to examine associations among the specific activities across different substrates. A strong and a significant negative correlation exists between the specific activities of Water 40K and Soil 232Th (r =-0.721, p<0.05); Water 238U and Soil 238U (r = -0.717, p<0.05) and Water 40K and Sediment 238U (r=-0.69, p<0.05). Comparison using Mann-Whitney U test shows that, soil and sediment are similar in their specific activities with Z values of -0.408, -1.209 and -1.021 (p > 0.05) for 40K, 232Th and 238U respectively. The concentration of solid samples (soil and sediment) is different from the liquid (water) samples. These associations can be attributed to some specific underlying factors. And in other to understand them there is need for more studies. © JASEM http://dx.doi.org/10.4314/jasem.v20i1.3 KEYWORDS: Radionuclide; environmental monitoring; Niger Delta; Gamma spectroscopy; Environmental management Introduction environment and other areas where human activities Human settlements such as cities and other urban have impacted, such could be increased as a results of settlements, create one of the most intense human anthropogenic factors. These factors could be in the interactions between humans and nature (Lawal, form of mining and combustion of coal; oil and gas 2009). These interactions could be seen in the form production; metal mining and smelting; mineral of the continuous flow of resources and materials sands, fertiliser industry; building industry and through the economy, which create both useful recycling– all of which tend to enhance NORM in the products and also create wastes which is often the environment (World Nuclear Association, 2014). cause of many of our environmental (Lawal, 2014) and health issues. The dominance of the oil and gas industry in Nigeria, makes it a very important industry along the coastal Radioactive materials could be naturally occurring region of Nigeria. With this dominance is the radioactive materials (NORM) and technologically attendant impacts on the environment, especially in enhanced NORM (TENORM). Knowledge and relation to the potential enhancement of NORM understanding of the distribution of these is very across the coastal region. Thus, it could be said that important in assessing their potential health and the industries potentially increases TENORM environmental impacts. In nature, NORM concentration across this region. Looking at the concentration are usually dependent on the location peculiarities of the region, high annual rainfall, high and geological characteristics (United Nations. water table (Nwankwoala and Omunguye, 2013) and Scientific Committee on the Effects of Atomic shallows borehole/wells for potable water, minimal Radiation, 2000). Processes (such as weathering, coverage of pipe borne water utility (Water and rainfall, and runoff) within the natural environment Sanitation Department, 2014) the risk to public health acting on rocks facilitate the enrichment and is quite significant. The industries and activities distribution of radionuclides in the soils. Therefore, previously mentioned, utilises a considerable amount their specific activity in the soil can be used as the of NORM, which often end up in effluents natural background radiation. But, within the urban originating from them all of which has a very high *Corresponding author’s contact: Tel.: +2349097347063; Email: [email protected] Monitoring of specific activities of long-lived radioactive elements 26 probability of ending up in water bodies (and or environmental quality and quality of life across the groundwater). This potentially has a negative impact country. on the quality and ecology of the water bodies. This To this end, the objectives of the study is to: understanding has resulted in the monitoring and regulation of some of these industries, although, there Examine the association among soil, is a great deal of inconsistency in these regulations sediment and water specific activity of across countries and industries (World Nuclear selected radionuclides. Association, 2014). Determine the differences among the specific activities of each radionuclide In Nigeria, for example, there are significant issues across substrates within the study area. with respect to public health and environmental management. These issues include lack of MATERIALS AND METHODS enforcement (zoning of industrial activities and Study Area: The study was carried out around the effluent standards) and loose/inefficient regulatory Mini-Okoro/Oginigba creek (Figure 1) located within framework as well as costs, equipment, coverage the Trans-Amadi Industrial Area of Port Harcourt problems in monitoring the environment. Therefore, Metropolis. According to the Köppen-Geiger climate to address some of these issues there is a need to classification (Rubel and Kottek, 2010), the study understand the dynamics and relationship among area belongs to the Tropical Monsoonal climate. This some of the environmental health indicators (in this is characterised by a short dry season and a case the specific activities of NORM/TENORM). pronounced wet season, with one or more months This understanding can help in filling gaps in data having less that 60mm of rain. All months have mean and thus allow for local, regional and national monthly temperature greater than 18oC and the modelling of NORM across the country, thereby highest annual temperature is usually experienced supporting initiatives that could enhance just before the onset of the rainy season. Fig 1: Topographic map of the location and features around the study area This creek is located within Port Harcourt, Rivers According to NDDC (2006), the pattern of settlement State, one of the largest cities in the Niger Delta is influenced by availability of dry land and the region of Nigeria. The State has three ecological nature of a big city like Port Harcourt on the zones – Mangrove forest and coastal vegetation; fresh mangrove swamp arises as a result of relatively better water swamps and lowland rainforest with the drainage conditions and accessibility. Furthermore, Mangrove forest and coastal vegetation being the the majority of top soils (60%) across the dominant most dominant (Niger Delta Development ecological zones (Mangrove forests and Coastal Commission, 2006). The landmass is on a coastal Vegetation) in the State are of low fertility. plain belonging to the Niger Delta sedimentary formation (Short and Stauble, 1967). The terrain has The Mini-Okoro Stream and the Oginigba Creek slopes ranging between an average of 3 and 5 degrees under study, drains the Freshwater swamp forest into towards the NW-SE direction, thus impacting on the Woji Creek which drains into the Bonny Estuary. The drainage of the area (poorly drained, low relief and stream is shallow and joins up with the Oginigba gentle slopes –consequently low river flow). Creek (a shallow, brackish, around 4km long and 100 1GREGORY O. AVWIRI, 2*OLANREWAJU LAWAL, 1EDITH I. NWOKEOJI Monitoring of specific activities of long-lived radioactive elements 27 -200m width), together emptying into the Bonny al, 2007). The samples were stored in Marinelli River (eventually the Estuary). Situated along this sample containers as well. water body are sawmills, Shell Petroleum Development Company, Pabod Breweries, Nigerian All samples were placed in the Sodium-Iodide Bottling Company, Schlumberger and many other oil Detector and counted for 10 hours, analysis was servicing companies. Furthermore, it is known that carried out at the National Institute of Radiation the breweries discharge their effluent into the creek Protection and Research (NIRPR) at the University of as well as the old Michelin Tyre manufacturing Ibadan, Ibadan. The instrument is a Model 802, company (no longer active). Other activities and coupled to Canberra Lead cylindrical shield of 10cm industries along the water body includes, boat thickness. Energy calibration used a set of building, welding and metallurgy, abattoirs, block International Atomic Energy Agency (IAEA) moulding (sand collection from stream), petrol standard (known) sources of radionuclides within a stations, electrical substations, household waste well-defined energy range (0.511 – 2.615MeV). dumping in the stream all contributed to polluting the Computation of the photo-peak of each of the stream. radionuclide was done