Physico-Chemical Characteristics of Wastewater at A Polyethylene Bag Manufacturing Company in Bekwai Municipality, Ghana

Abstract

This study investigated heavy metals and other physico-chemical parameters in effluents at a plastic manufacturing company in Bekwai municipality. Wastewater was sampled at different points of wastewater production and storage to help understand how unit operations affected effluent quality. Sampling and determination of physico-chemical parameters (pH, conductivity, total dissolved solids, total hardness, alkalinity) were carried out as described by the American Public Health Association (APHA). Heavy metals (Manganese (Mn), Mercury (Hg), Copper (Cu), Chromium (Cr), Arsenic (As), Cadmium (Cd), Lead (Pb), and Zinc (Zn)) were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) following standard protocol. The pH of the samples ranged from 7.59 – 8.1. The mean concentrations ranged from 0.001 to 0.069 mg/L, 0.001 – 0.037 mg/L and 0.013 – 0.017 mg/L for Pb, As and Cr respectively. Except for Pb and As, all physicochemical parameters and the remaining metals analysed values were below the permissible range for effluent discharge by the Environmental Protection Agency (EPA) of Ghana. A one-way analysis of the variance of all the heavy metals in the water samples analysed revealed statistically significant difference (p < 0.05) The estimated daily intake of Mn, Cu, Cr, Cd, Pb and Zn contained in the water samples analysed did not exceeded their recommended daily intake for children, however, As exceeded their acceptable daily intake of 0.0003 mg/kg/day for children. All metals were below their acceptable daily limit for adults. This result indicates the presence of toxic metals in effluent from polyethylene bag manufacturing companies which is of concern since these metals tend to bioaccumulate and affect aquatic life.