STUDYING THE EFFECT OF CEMENT DUST ON PHOTOSYNTHETIC PIGMENTS OF PLANTS ON THE EXAMPLE EWEKORO CEMENT INDUSTRY, NIGERIA

Abstract

Most technogenic human activities in quest for industrialization and civilization interfere with ecological safety and biodiversity − all of which are deleterious to the continual existence of life on Earth. This study examined the effect of cement dust from Ewekoro cement industry, Nigeria on the photosynthetic pigments of Ocimum gratissimum, Mangifera indica, Terminalia catappa, Jatropha curcas and Carica papaya. Samples of these endemic plant species were taken at 500 m, 1000 m, 1500 m, 2000 m and 6000 m away from the cement industry. Supernatants taken during Laboratory analysis was used for absorbance readings, using UV-VIS spectrophotometer at 662, 645, 470, 435 and 415 nm wavelength to determine the concentrations of chlorophyll A, chlorophyll B and carotenoids. Results show that chlorophyll A, B, total chlorophyll and carotenoids were reduced in all the plants species exposed to cement dust compared to the control site. The rate of degradation of photosynthetic pigments was high in all the investigated species but significantly higher in Ocimum gratissimum and Mangifera indica. All the plant species except Terminalia catappa showed a decline in carotenoid content. Specifically, Mangifera indica had the highest reduction of chlorophyll (91.03 %), followed by Ocimum gratissimum (77.40 %) among other plant species investigated at 500 m away from the factory site. The lowest reduction in percentage of chlorophyll was observed in Carica papaya. This study infers that cement dust pollution could possibly cause a decline in photosynthetic pigments of leaf extracts and hence, affects plant productivity. Future research should exhaustively examine and perhaps predict the concentration and effect of cement dust on the environment (including both fauna and flora) in 20 years to come via appropriate toxicokinetic models and also they should consider the impact of cement dust on nutritive value of plants. If these prospective studies are conducted, then this will help to choose and apply the organizational measures and technical means to protect the components of nature