Assessment of Vegetation, Aquatic and Public Health Issues
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Assessment of Vegetation, Aquatic and Public Health Issues Issues of contamination and ensuing environmental damage are consequences of oil industry operations that are impacting the health, welfare and livelihoods of the Ogoni community © Mazen Saggar UNEP ENVIRONMENTAL ASSESSMENT OF OGONILAND environmental damage are consequences of oil Assessment of industry operations that are impacting the health, Vegetation, Aquatic and welfare and livelihoods of the Ogoni community. If sustainable environmental improvement and, Public Health Issues indeed, sustainable development of Ogoniland are to become a reality, the issues discussed in this Chapter 4 dealt with site-specific land contamination chapter need to be addressed concurrently with issues where the focus was on soil and groundwater clean-up of contaminated sites. contamination. Sites were assessed on a case-by- case basis, where it was often possible to pinpoint the source of the contamination and identify 5.1 Impact of oil on tide- the operator responsible for clean-up. Soil and dominated delta swamps groundwater contamination is a regulated issue in and mangroves Nigeria and operators have procedures in place to manage such incidences. Mangrove ecosystems, together with seagrasses and coral reefs, are among the world’s most productive In this chapter, contamination of non-site specific natural ecosystems. They are characterized by a environmental media, such as air and surface dynamic equilibrium between flooding, erosion water, is discussed, as is the fate of receptors and sediment deposition and are adapted to such as human beings, fish and mangroves, frequent changes in the shoreline. The mangrove all of which can receive pollution from more trees and bushes are keystone species of central than one source. As pollution incidents are importance for brackish wetland ecosystems diffuse, responsibility cannot be assigned to a and the terrestrial and aquatic organisms which single event or single operator. In the specific inhabit them. Consequently, mangroves are context of Nigeria, ambient environmental not just ecologically significant but are critical monitoring and compliance are not well regulated. to the livelihood and food security of the delta However, issues of contamination and ensuing community. © MAZEN SAGGAR Ogoni people live with contamination of air and surface water every day 154 s5NITED.ATIONS%NVIRONMENT0ROGRAMMEs5NITED.ATIONS%NVIRONMENT0ROGRAMMEs5NITED.ATIONS%NVIRONMENT0ROGRAMMEs 5 VEGETATION, AQUATIC & PUBLIC HEALTH ISSUES seismic lines Seismic lines at Ogu Bolo, November 2010 In addition to its productive functions, increasingly The red mangroves (Rhizophora spp.) are by far the other ecosystem services of mangroves are being most abundant. R. racemosa is the most common understood. Key among these is protection and tallest of the genus, reaching a height of up against storm surges and smaller Tsunami waves. to 40 metres in favourable conditions, but often A comprehensive review of the mangroves in forming shrubby tangles up to 10 metres high, Western and Central Africa, including their with stilt roots – tall arching roots originating crucial importance to the livelihood in that from trunks and branches which supply air to region is presented in a recent publication from the underlying roots and provide support and UNEP [44]. The following sections provide some stability. It fruits at most seasons and the wood is information relating to Ogoniland. very hard, suitable for durable construction poles and firewood of high calorific value. R. racemosa A number of species typical for mangrove is a pioneer species and has a high salt tolerance, ecosystems found in West Africa occur in colonizing the mud on the outermost fringes of Nigeria: Acrostichum aureum (an introduced erect, vegetation between high and low tide. As the mud mangrove fern from the neotropics), Avicennia dries out closer to land, it disappears. germinans, Conocarpus erectus, Laguncularia Lasting impressions of seismic surveys racemosa, Rhizophora mangle, Rhizophora harrisonii, Rhizophora racemosa and the mangrove palm Nypa Oil exploration activities started to have an impact fruticans. All were found in Ogoniland during on the Niger Delta vegetation even before a well UNEP’s fieldwork, with the exception of C. erectus was drilled or oil produced, and the footprint left and R. harrisonii, although in all likelihood both by seismic surveys over 50 years can still be seen. are present. In addition, Raphia spp. and Phoenix Though not extensive in scope or devastating in reclinata are present as mangrove associates. nature, it is instructive to note that even decades s5NITED.ATIONS%NVIRONMENT0ROGRAMMEs5NITED.ATIONS%NVIRONMENT0ROGRAMMEs5NITED.ATIONS%NVIRONMENT0ROGRAMMEs 155 UNEP ENVIRONMENTAL ASSESSMENT OF OGONILAND after this disturbance, natural processes have not influx of freshwater to mangrove communities, may yet managed to close the gap created by the seismic lead to degradation and ultimaltely destruction of lines. Some reports state that oil industries continue the mangrove community [46]. to keep the seismic lines open for future use [45]. Seismic lines may make the interior of some While no dredging was seen to be taking place in wetland areas more accessible, potentially leading the creeks around Ogoniland during the UNEP to further degradation. assessment period, evidence of dredging can be seen from satellite images. Channels that have been Impact of dredging dredged or widened and the resulting spoil are all clearly evident in satellite images even now, decades The large number of meandering water courses after the dredging operation. makes access to oil exploration and production sites difficult in delatic region. The development Without proper rehabilitation, former mangrove of oilfield infrastructure in the mangrove zones areas have been converted to bare ground which therefore requires dredging and/or vegetation eventually may become colonized by invasive species clearance and the creation of canals to open such as nipa palm. The impacts of dredging on navigable routes. During dredging, soil, sediments mangroves are far reaching because it affects almost and vegetation along the access route of the all components of the ecosystem, including the proposed site are removed and typically disposed of mangrove vegetation itself, benthic invertebrates, over banks, in most cases upon fringing mangroves, fisheries, plankton, wildlife, soil, sediment and water and then abandoned (Map 17). The abandonment quality – and ultimately the local communities who of the resulting dredged material has a number of depend directly on the rich mangrove ecosystem for environmental impacts. These include smothering of their subsistence [47, 48]. fringing mangroves, alteration of surface topography and hydrology, acidification, accumulation of heavy Impact due to physical disturbance metals and water contamination, which together in the Niger Delta have resulted in damage to vegetation Mangroves in the creeks around Ogoniland have and killing of fish [45]. Importantly, hydrological been very badly affected by physical disturbance, changes, such as increased salinity or lack of regular both through increasing use of the mangrove A right of way more than 30 metres wide cut through mangroves 156 s5NITED.ATIONS%NVIRONMENT0ROGRAMMEs5NITED.ATIONS%NVIRONMENT0ROGRAMMEs5NITED.ATIONS%NVIRONMENT0ROGRAMMEs 5 VEGETATION, AQUATIC & PUBLIC HEALTH ISSUES -AP 3ATELLITEIMAGESHOWINGDREGDGING"ODO7EST "ONNY,'! ELEME ° TAI GOKANA OGU/BOLO Dredged channels OKRIKA BONNY ETCHE OBIO/AKPOR OYIGBO ELEME TAI OKRIKA KHANA OGU/BOLO GOKANA Satellite : Landsat Acquisition date : 1986 © Nasa BONNY Meters ANDONI DEGEMA 0 1 300 2 600 s5NITED.ATIONS%NVIRONMENT0ROGRAMMEs5NITED.ATIONS%NVIRONMENT0ROGRAMMEs5NITED.ATIONS%NVIRONMENT0ROGRAMMEs 157 UNEP ENVIRONMENTAL ASSESSMENT OF OGONILAND forests by a growing human population in the (saturated hydrocarbons) and dominance of coastal zone and in particular from oil exploration pristine/phytane isoprenoids (naturally occurring and production activities. When the pipeline for organic chemicals). In practical terms this means carrying product from Bodo West flow station that the material sticking to the vegetation is was laid, for example, it was partly routed through highly bituminous, and will not biodegrade or mangroves. A right of way 30 metres wide was cut dissolve in water, even if the water is in constant and was observed during the UNEP study to be contact with the hydrocarbon. still clear of vegetation. The edges of the right of way appear to have been dredged, allowing floating oil to spread over the soil along the entire right of way, gradually destroying the fringing mangroves and contaminating land (Map 18). Impact due to oil pollution The impact of oil on mangrove vegetation in Ogoniland has been disastrous, as was evident to the UNEP team during an early reconnaissance mission along the creeks. Impacts vary from extreme stress to total destruction. In the most impacted areas, only the roots of the mangroves remains, with no stems or leaves. The roots are completely coated in oil, sometimes with a 1 cm or more thick layer of bituminous substance. The pollution has accumulated over a very long period, perhaps over decades. Mangroves coated with oil will probably die From a typical GC fingerprint of the hydrocarbon coating the mangrove roots (Figure 14), it can be seen that the hydrocarbon is highly degraded with Mangroves roots heavily coated by a thick layer extensive depletion of low molecular mass