Heavy metal levels in drinking water sources and their potential human health risks in Chingola district of Zambia

Abstract

One of the factors impeding access to safe water is water pollution. Of particular concern is heavy metal contamination of water bodies. This study was aimed at determining the levels of heavy metals in drinking water sources of Chingola District of Zambia and their potential human health risks in Chingola District of Zambia. A cross sectional study design was used. A total of 60 water samples were collected. 30 water samples were collected in the dry season in the month of October, 2016 and another 30 were collected in the wet season in the months of February and March, 2017. For each season 10 water samples were collected from each of the three water sources. i.e. Tap water, Urban ground water sources and Rural ground water sources. Heavy metal analysis was done using Atomic Absorption Spectrophotometer (AAS). This study revealed that concentrations of Iron, Manganese, Lead, Nickel and Arsenic were beyond maximum permissible levels in various water sources. Chromium and Cadmium was below detection limit in all water samples. The median concentrations of iron, arsenic, copper and manganese in drinking water from the Tap, rural and urban ground water sources were different, and this difference was statistically significant (p<0.05). The median concentrations of arsenic, nickel, manganese and cobalt were different between dry and wet season, and this difference was statistically significant (p<0.05). Non- carcinogenic risk assessment revealed that arsenic, iron, lead and copper are heavy metals which are likely to produce non carcinogenic adverse health effects. Carcinogenic risk assessment showed that the levels of arsenic and lead have a high likelihood of producing carcinogenic adverse health effects. Sources of heavy metals in water seems to be both natural and from human activities. The water utility company should improve its water treatment processes and rural communities should be provided with household water filters.