RAINY SEASON DISTRIBUTION OF HEAVY-METAL POLLUTION INDEX ALONG OKULU RIVERS IN ELEME LGA OF RIVERS STATE, NIGERIA

Osuji, F. C.; Ugwoha, E.; Yorkor, B.

Authors

Osuji, F. C.
Ugwoha, E.
Yorkor, B. Center for Occupational Health, Safety and Environment, Institute of Petroleum Studies, University of Port Harcourt, Rivers State, Nigeria

Keywords:

Heavy-metals, Pollution Index, Rainy Season, Okulu River

Abstract

This study was conducted in order to determine the rainy season distribution of heavy metal pollution index (HPI) along Okulu rivers in Eleme local government area of Rivers State. Water samples were collected from distances of 100, 200, 300, 400 and 500m away from petrochemical effluent discharge point into the river using well-washed and rinsed bottles. Heavy metal contents of the water samples were analyzed specifically for cadmium, chromium, copper, lead, Iron, Nickel and Zinc. The heavy-metal pollution indices of the various samples were evaluated using the weighted average formula based on WHO and FME surface water standards. The results revealed that the HPI for the water samples at distances of 100, 200, 300, 400 and 500m away from effluent discharge point based on FME standards were 9771, 6325, 10681 and 5814 which indicated that the water samples were unfit for both domestic, Irrigation and industrial purposes while the HPI for the water samples at distances of 100, 200, 300, 400 and 500m away from effluent discharge point based on WHO standards were 35.06, 45,95, 95.30 109.87 and 205.43 which showed that water sample from distances of 100 and 200m away from discharge point are suitable for industrial and irrigation purposes but not for domestic purposes while water samples beyond 200m are not suitable for both domestic, industrial and irrigation purposes. The model of the distribution of the HPI along the sampled area revealed that there is non-linear sinusoidal relationship between HPI and distances along the sampled points. It was concluded that the river is highly polluted with heavy metals and the heavy metals are unevenly distributed along the river. It was recommended that communities along the Okulu rivers should not use the water from this river for both domestic, irrigation and industrial purposes due to high level of heavy-metal contents that could pose serious threat to their health.