Evaluation of the Ecological Impact of Human Settlement on the Water Quality of Lower Cross River, Nigeria

The ecological impact of human settlement on the water quality of Lower Cross River, Nigeria was evaluated. The physical and chemical conditions of the river water were determined from January to August, 2011. Three stations comprising Itu in Akwa Ibom State with intense human activities (station 2), its upstream (without human settlement) at Cross River State (station 1) and the downstream (station 3) were sampled. The Parametric One Way Analysis of Variance (ANOVA) indicated that of the 17 physical and chemical parameters determined, only water level and COD were found to be significantly different ( ) among stations. The spatial variations in the level of significant correlation of the physical and chemical parameters among the stations and the higher level of interrelationship in downstream station 2 and 3 than station 1 could be attributed to inputs resulting from human settlement. Comparison between some parameters with Standard Organization of Nigeria, and World Health Organization maximum permitted levels for drinking water indicated that the water was not polluted. However, the BOD and COD concentrations of greater than 2？mg/L and 20？mg/L respectively were indicative of pollution. 1. Introduction The lower Cross River which originated from Cameroon is the main river in southeastern Nigeria and gives its name to Cross River State, Nigeria. The river serves as the main source of water for domestic and agricultural purposes, source of shell and fin-fish for the major communities settling along its banks. Human settlements are recognized as ecological systems, in the sense that they are “habitat systems” for human populations, which may be directly comparable with “natural” ecosystems [1]. Clean, safe, and adequate freshwater is vital to the survival of all living organisms and the smooth functioning of ecosystems, communities, and economics. Declining water quality has become a global issue of concern as the growth of human populations, expansion of industrial/agricultural activities, and terrible threats of climate changes alternate the hydrological cycle. Water quality issues are complex and diverse and are deserving of urgent attention and action [2]. Human are adjudged to be the principal drivers of change on the earth’s surface. Such impact may shape the earth in small subtle ways and sometimes in big catastrophic ways [3, 4]. Ecosystems are damaged by degraded water quality, among other factors. The biodiversity of freshwater ecosystems has been degraded more than any other ecosystem, including tropical rainforests [5]. Data existing on the