Drinking water: a major source of lead exposure in Karachi, Pakistan

Abstract

Excess lead in drinking water is a neglected source of lead toxicity in Pakistan. A cross-sectional survey in 2007/08 was made of water samples from drinking water sources in Karachi, a large industrial city. This study aimed to compare lead levels between untreated ground water and treated surface (tap) water in 18 different districts. Of 216 ground and surface water samples collected, 86% had lead levels higher than the World Health Organization maximum acceptable concentration of 10 ppb. Mean lead concentration in ground water [146 (SD 119) ppb] was significantly higher than in surface water [77.1 (SD 54) ppb]. None of the 18 districts had a mean lead level of ground or surface water below the WHO cut-off and ground water sources in 9 districts had a severe level of contamination (> 150 ppb). Urgent action is needed to eliminate sources of contamination.

Lead Exposure Assessment among Pregnant Women, Newborns, and Children: Case Study from Karachi, Pakistan

“…Some of the previous investigations had also misled the researchers and policy makers. For example, water has been implicated as a major source of exposure for taking countermeasures against lead [24]. This study clearly identified that water was not a major source of exposure among the pregnant women and children.…”

“…Another study conducted in Karachi city found that umbilical cord blood levels were higher among mothers living in houses with windows open, those using surma daily, and in households where the mothers took no calcium or less iron supplements during pregnancy [12]. In one study, water has also been found as a major source of lead in Karachi [24]. All of these studies point to one or the other source of lead exposure.…”

Effects of Solution Matrix on Moringa oleifera Seeds and Banana Peel in Eliminating Heavy Metals, Fluoride and Turbidity from Synthetic Groundwater Samples

“…The chemical stock solutions such as lead carbonate (PbNO 3 ), nickel carbonate (NiCO 3 ), cadmium nitrate tetrahydrate (Cd(NO 3 ) 2 .4H 2 O), arsenic trioxide (AsO 3 ), sodium fluoride (NaF) and kaolin powder (Al 2 Si 2 O 5 (OH) 4 ) were obtained from Sigma Aldrich (Australia). Prior to single-and multi-contaminant samples preparation, stock solution for every chemical was prepared depending on the desired concentration (determined based on the previous experimental results as presented in [1] & [2]. The concentrations of each target contaminant are presented in Table 1.…”

“…Groundwater is often regarded to possess acceptable quality compared to surface water which can easily get contaminated by surrounding pollution contributing from uncontrolled storms and runoff events. However, according to Ul-Haq et al [2], the sources are now vulnerable to the various harmful chemicals that may introduce by the discharge of untreated effluents from industrial activities and leach from pipeline materials into the groundwater.…”

The Challenges of Water Pollution, Threat to Public Health, Flaws of Water Laws and Policies in Pakistan

“…A survey of drinking water samples in Karachi in 2007/08 found that, of 216 ground and surface water samples collected, 86% had lead levels higher than the WHO maximum acceptable concentration of 10 parts per billion (ppb). This mean lead concentration was 146 ppb in untreated ground water and 77 ppb in treated tap water [28]. Newspapers reported that a citizen of Karachi submitted a court petition asking the Karachi Water and Sewerage Board (KWSB) to fulfill its duty to provide clean water.…”