Influence of Industrial Wastewater in Douala City on Growth, Chlorophyll and Cadmium Levels of Vigna unguiculata of Economic Importance

摘要

Over the world, biodiversity conservation issues related to environmental protection are vital. Douala is one of the cities where water pollution is important. Thus, a comparative study has been carried out on some growth parameters (germination, leaf surfaces, length of stem, number of leaves), chlorophyll and cadmium contents in leaves of Vigna unguiculata grown at the vicinity of three polluted water discharged sites (Azur, Industrial Zone of Bonaberi and Abattoir of Bonendale) and a non-polluted site (control). The methodology consisted of sowing cowpea in both polluted and unpolluted sites and then the growth parameters were taken every two days for six weeks during which chlorophyll in the leaves was measured after thirty days. Moreover, the degree of pollution of waste water was analyzed in the laboratory based on physicochemical parameters. The results show that plant growth is abnormal in contaminated sites (Industrial Zone of Bonaberi, Azur and Abattoir of Bonendale and the average chlorophyll (a + b) of the leaves is 36.32 for the control and 11.23; 5.26; 17.42 respectively for polluted sites (Azur, Industrial Zone of Bonaberi and Abattoir of Bonendale). These values are significantly different. Plants in the control site concentrate less Cadmium than those in polluted sites. The Cadmium maximum absorption is observed in a site located in the Industrial Zone of Bonaberi with nearly six times the value of the control.