Lead induced oxidative DNA damage in battery-recycling child workers from Bangladesh

Abstract

Lead exposure can damage cells directly by effecting DNA or indirectly by modifying proteins and enzymes. In Bangladesh, many working children are exposed to a very high level of lead during their early life due to their involvement with lead-oriented professions. This imposes a severe threat to the growth and development of the children. Therefore to study the effect of lead, we enrolled 60 age-matched male children, from an area of old Dhaka city, where battery-recycling shops are located, depending on their blood lead concentration. If the children had a plasma lead concentration above the WHO recommended threshold level of 10 µg/dl, we grouped them as test subjects and others as control subjects to determine the effect of lead on different biochemical parameters of the body. Compared to the controls, acculumlation of the lipid peroxidation product, malondialdehyde, increased significantly in test subjects ( p < 0.01). Lead exposure also increased the protein carbonyl content ( p < 0.05) and significantly decreased the plasma glutathione levels of test subjects compared to the controls ( p < 0.05). While comparing the lead-exposed group against controls, it was found that the percentage of damaged DNA, as measured using the Comet assay, significantly increased in tail ( p < 0.01) and decreased in head regions. All of these results suggest that high-plasma lead content may induce an oxidative stress to the study population, which may lead to DNA damage.

The Health Impacts of Hazardous Chemical Exposures among Child Labourers in Low- and Middle-Income Countries

“…Three papers assessed oxidative stress and DNA damage caused by lead exposure [69] or a combination of metals [14,59]. All three reported significantly altered oxidative stress parameters in exposed groups, with two [14,69] reporting increased DNA damage.…”

“…Three papers assessed oxidative stress and DNA damage caused by lead exposure [69] or a combination of metals [14,59]. All three reported significantly altered oxidative stress parameters in exposed groups, with two [14,69] reporting increased DNA damage. Specifically, Lahiry et al's low quality paper stated that one marker of DNA damage was 15.6 times higher in the exposed group, although limitations in study methodology must be considered [14].…”

“…Specifically, Lahiry et al's low quality paper stated that one marker of DNA damage was 15.6 times higher in the exposed group, although limitations in study methodology must be considered [14]. One paper also found that those exposed had decreased body weight compared to controls [69].…”

Dynamics of Lead Bioavailability and Speciation in Indoor Dust and X-ray Spectroscopic Investigation of the Link between Ingestion and Inhalation Pathways

“…Following the displacement of particulate matter from air into the aqueous phase, Pb solubilization in lung fluid may result in absorption into the blood via the air–blood barrier . Solubilized transition metals may cause localized pulmonary toxicity, translocate to extra-pulmonary organs (e.g., heart and liver), and exert systemic toxicity (e.g., DNA and hepatic damage by oxidative stress). − …”

“…8 Solubilized transition metals may cause localized pulmonary toxicity, 10 translocate to extra-pulmonary organs (e.g., heart and liver), 11 and exert systemic toxicity (e.g., DNA and hepatic damage by oxidative stress). 12 Unlike the ingestion pathway, where Pb absorption may be influenced by the nutritional status (i.e., fed vs unfed, cations, and lipid composition of diet), 15,16 a higher fraction of solubilized Pb may be absorbed in the lungs because of the high surface area and extensive vascularization of the respiratory system, coupled with the short air−blood barrier separation. 17 Inhalation studies in humans using Pb particles (<1 μm) have reported that up 95% of Pb deposited in the lungs was absorbed, 18,19 with a half-life of 0.8−44 h in the blood, 20 while ultrafine particles (<100 nm) may be immediately absorbed (e.g., Pb fumes).…”