Environmental sensitivity index mapping of carbon steel corrosion in ndoni river, ahoada river, new calabar river, tombia river, buguma river and bonny estuary

Industrialization and modernization has led to high demand of energy resources thereby increasing the transportation and demand of crude oil and its products via different types of steel products which are prone to wear and tear leading to spillages of all forms in marine, brackish and fresh water habitats. This study is aimed at creating an environmental analysis index corrosion map of the shorelines of Ndoni river, Ahoada river, New Calabar river, Tombia river, Buguma river and Bonny estuary as well as determine corrosion rates of carbon steel coupons on these shorelines. Different methods of shoreline sensitivity were used in this study which includes that of National Oceanic and Atmospheric Administration (NOAA) and Nigeria Oil Producing Trade Sector (OPTS). A total of eight ESI types were found in the area and they include 1b, 3a, 4a, 6b, 9b, 9c, 10a and 10b. The most prevalent faunas found in these shorelines include crocodile, iguana, sea turtle, jellyfish, tilapia, frog, snail, toad, white crab, shorebirds, earthworm and millipede. Spearman`s correlation coefficient (r) value of 0.93 was the result of the relationship between the number of socioeconomic features and biological species along the shorelines. The corrosion rates of the carbon steel coupons in the various shorelines of Ndoni river, Ahoada river, New Calabar river, Tombia river, Buguma river and Bonny estuary are 44.068g/yr, 69.912g/yr, 72.435g/yr, 86.559g/yr. 119.420g/yr and 191.591g/yr respectively. The carbon coupons had lower corrosion rates in freshwater habitats followed by brackishwater habitats and highest in the estuarine habitat. Results from this study can serve as a quick reference point for oil spill responders as well as integral component of oil spill contingency planning, corrosion monitoring and decision making on type of steel to use on these various habitats.