Impact of Meteorological Events and Sand Excavation on Turbidity and Total Suspended Solids Levels of Imo River by Dr. Chinedu E. Ihejirika Department of Environmental Technology, Federal University of Technology, Owerri, Nigeria at ICCEB 2015: XIII International Conference on Climate, Environment and Biosciences in Miami, USA March, 9-10, 2015

INTRODUCTION Challenges faced by fresh water bodies in developing countries include the following: (a) Anthropogenic impacts: + Industrial effluent and domestic sewage discharges + Dumping of solid wastes + Sand mining/ excavation + Dredging, etc. (b) Natural impacts: + Climate change (rainy and dry seasonal effects) + Flooding + Wind-induced currents

Fig. 1. Percentage Monthly Rainfall in Nigeria

Fig. 2. Sand Excavation in a Nigerian River

Fig. 3. Flooding in a Nigerian City

Fig. 4. Dumping of Solid Waste on Drainage Paths

Fig. 1. Map of Study Area

MATERIALS AND METHODS + Sample Collection: Water samples were collected at 7 major points of sand excavation activities at the peaks of the seasons; the dry season,-between November and March, while the rainy season was between May and September, for two consecutive years. + Chemical analysis: Turbidity (NTU) and Total Suspended Solids (TSS) (mg/L) levels of the water samples were determined as described in the Standard Methods for the Examination of Water and Wastewater (1998).

SEASONAL VARIATION IN TURBIDITY AND TSS RESULTS AND DISCUSSION TABLE I SEASONAL VARIATION IN TURBIDITY AND TSS Locations Season Turbidity TSS Ekenobizi Dry 28.00±1.00A 17.00±1.00A Rainy 50.00±1.00A 39.00±1.00A Udo Dry 37.00±1.00A 20.00±1.00A Rainy 44.00±1.00A 28.00±1.00A Owerrinta Dry 16.00±1.00A 6.00±1.00A Rainy 43.00±1.00A 36.00±1.00A Alulu Dry 7.00±1.00A 6.00±1.00A Rainy 37.00±1.00A 23.00±1.00A Owaza Dry 9.00±1.00A 4.00±1.00A Rainy 37.66±0.58A 23.00±1.00A Obigbo Dry 14.00±1.00A 3.00±0.00A Rainy 33.00±1.00A 27.00±1.00A Akwette Dry 8.00±1.00A 6.00±1.00A Rainy 50.00±1.00A 37.00±1.00A At P =0.05, values with A - letter are significantly different while values with B – letter are not significantly different from each other

Fig. 2: Relationship Between Turbidity and TSS

There were notable variations in values of turbidity and TSS between seasons. Values were higher during the rainy season than the dry season. Sand excavation might have influenced increased values of parameters at the sampling points.

Consequences of Increasing Turbidity and TDS Levels on River Quality (a) Wind-induced currents re-suspend sediments in shallow waters (b) Reduced penetration of light, temperature changes, and sedimentation (c) Physical alteration: - undesirable aesthetic effects - higher costs of water treatment - reduced navigability of channels - decreased longevity of dams and reservoirs

Consequences of Increasing Turbidity and TDS Levels on River Quality (Contd.) (d) Chemical alterations: - release of contaminants, such as heavy metals and pesticides, and nutrients such as phosphorus, into the water body from adsorption sites on the sediment - add high organic content, depleting levels of dissolved oxygen in the water, producing a critical oxygen shortage which can lead to fish death during low-flow conditions.

Consequences of Increasing Turbidity and TDS Levels on River Quality (Contd.) (e) Biological effects: - fine sediment deposited on the streambed can fill gravel spaces, eliminating spawning habitat for some fish species and many invertebrate species - reduce light penetration, decreasing algal growth, and low algal productivity, reducing the productivity of aquatic invertebrates, a food source of many fishes

Consequences of Increasing Turbidity and TDS Levels on River Quality (Contd.) - Gill function in some fish may also be impaired after 5 to 10 days of exposure to a turbidity level of 25 NTU - Large bed loads can also reduce or eliminate pool habitat essential to low-flow and dry season survival of fish - Increased turbidity, TSS and acidity and the depletion of oxygen tension of the water might cause 91% and 72% reduction in zooplankton population and taxa respectively following dredging

CONCLUSION This study confirmed the impact of meteorological events like seasonal (rainy and dry seasons) variations and sand excavation on the turbidity and TSS values of Imo River and that the subsequent increase in TSS and turbidity levels may lead to adverse consequences on the river quality and aquatic biota in the habitat.

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