EC Pharmacology and Toxicology

Flooding influences soil biochemical properties and enzymatic activities in floodplain ecosystems. This study assessed the impact of flooding on drainage and key soil enzyme activities such as catalase, lipase, urease, and phosphatase in some communities in Imo and Anambra states Nigeria. Soil samples were collected from six distinct high risk flood locations using soil auger. At each location, soil samples were gridded and collected with depths; 0 - 15 cm, 15 - 30 cm and 30 - 45 cm, representing top soil, sub soil and bottom soils respectively. Two control samples were also collected from high elevation towns within the Local Government Areas, not affected by flood. Morphological result revealed that inadequate drainage results in anaerobic conditions that facilitate changes in microbial activity and enzyme regulation. Results of enzyme activities showed spatial variations across the communities. Catalase activity ranged from 0.7433 ± 0.09 to 1.0933 ± 0.26 µmol kg^-1, with the highest levels recorded in Ekeugba and Amafor, indicating enhanced oxidative stress responses in frequently flooded sites. Lipase activity exhibited the widest variability 429.36 ± 366.38 to 721.35 ± 44.84 µmol kg^-1, suggesting differential organic matter turnover and lipid hydrolysis among the locations. Urease activity, an indicator of nitrogen mineralization, was highest in Akili-Ozizor 141.80 ± 50.36 µmol kg^-1 and lowest in Ihiala 79.13 ± 34.70 µmol kg^-1, reflecting differences in nitrogen cycling potential. Phosphatase activity, which governs phosphorus mobilization, peaked in Atani 162.28 ± 37.93 µmol kg^-1 and was lowest in Odekpe 90.95 ± 32.17 µmol kg^-1.

 Keyword: Flooding; Soil Microbial Enzymes; Catalase; Lipase; Urease; Phosphatase; Southern Nigeria

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