Prof. Dr. Ahmad Kamruzzaman Majumder :
Lead (Pb) is an elemental heavy metal found naturally in the environment as well as in manufactured products. Lead can be released directly into the air, as suspended particles. Lead poses a severe threat to human health and the environment. Many populations have been exposed to environmental lead from paint, petrol, and mining and smelting operations in Bangladesh.
Major sources of lead air emissions were motor vehicles and industrial sources. From July 6th 2000, lead has been removed from gasoline in air emissions of lead from the transportation sector in Bangladesh, and particularly the automotive sector, have greatly declined. However, because it was emitted in large amounts from vehicles when leaded gasoline was used, lead is present in many soils (especially urban soils) and can get re-suspended into the air. The major sources of lead emissions today are ore and metals processing, particularly lead smelters, and piston-engine aircraft operating on leaded aviation gasoline. Other stationary sources include waste incinerators, utilities, and lead-acid battery manufacturers. Lead that is emitted into the air can be inhaled or can be ingested, primarily through contact with contaminated soils or other surfaces.
Worldwide lead production and consumption have significantly increased along with unplanned industrialization and urbanization. Lead can be released into soil, air and water through soil erosion, volcanic eruptions, sea spray and bushfires.
The World Health Organization’s (WHO) 2021 update of the Public health impact of chemicals: knowns and unknowns estimate that nearly half of the 2 million lives lost to known chemicals exposure in 2019 were due to lead exposure. Lead exposure is estimated to accounts for 21.7 million years lost to disability and death (disability-adjusted life years, or DALYs) worldwide due to long-term effects on health.
Lead’s health effects in Bangladesh: Humans have used lead in various applications for thousands of years, with some of the past uses having left behind serious environmental and human health problems. Exposure to lead-contaminated air, soil and dust result in lead enters in our body, then it is distributed to organs such as the brain, kidneys, liver and bones.
In Bangladesh, illegal recycling of used lead-acid batteries (ULABs) in the open-air and close to homestead areas is considered to be a major source of lead exposure. This poses a significant health risk for both children and adults. Childhood lead exposure has also been linked to mental health and behavioural problems and to an increase of crime and violence. Adult people suffer severe consequences including increased risk of kidney damage and cardiovascular diseases in later life. In 2020, according to the Institute of Health Metrics Evaluation (IHME), Bangladesh has the world’s fourth-highest rate of death due to lead exposure with an average population blood lead level of 6.83 µg/dL, which is the eleventh highest in the world. The report estimates that the economic loss due to lead-attributable IQ reduction in Bangladesh is equivalent to 5.9 per cent of the country’s GDP. Lead poisoning hampers children’s ability to fully develop and prevents them from taking the maximum advantage of the opportunities in life.
A research study found that women in rural Bangladesh had unexpectedly high blood lead levels, which increased consider ably from early pregnancy to lactation, indicating elevated exposure to the fetus and the breastfed child. This study also addressed the moderate association between lead concentration in drinking water and BLL among young children. In 2015 a research study stated that, elevated pb level in consumption of fish, vegetables, cereals, and fruits associated with lifetime carcinogenic risk to the consumers. During the period of (1995-2002) the capital Dhaka’s atmosphere was worst in terms of high Pb concentration from leaded gasoline. Apart from, the mean BLL among 49 children from Tejgaon, Mohammadpur, and Keraniganj areas in Dhaka was 17.6 µg/dL, according to a research study.
Besides, from other research studies discovered that the mean BPb level was 15.0 µg/dL (range 4.2-63.1 µg/dL) among primary school children and most students (87.4%) had BPb levels above the Centers for Disease Control and Prevention’s level of concern (5 µg/dL). Afterwards, government banned leaded gasoline along with two stroke baby taxi from the urban areas of Bangladesh. But over the time the Pb concentration in urban area has increased again due to industrialisation in and around Dhaka city and some other minor possible sources such as open garbage disposal and pottery glazing. In a study showed, an industrial area, 104/105 (99%) samples of school students tested had BLLs =10 µg/dL compare to non-industrial area in Dhaka region.
Bangladesh has a limited planned waste treatment and recycling facilities. Untreated wastes are discharged into nearby agricultural lands, rivers, roadside canals or streams. Lead from these sources can persist in the soil and water bodies that human can take up through the food chain. Mostly, the deposition of lead found in soil, crops, water, air and vegetables is higher in Bangladesh’s industrial and urban areas.
Adding more that since 31st of December, 2002 two and three-stroke engines has been major contributor to atmospheric lead pollution in Bangladesh. After banned the two and three-stroke engine the atmospheric lead pollution reduced than but now some environmentalist observation found that the incomplete fuel combustion from vehicles in the urban area rising the lead toxicity in the air along with other sources.
The lead pollution in Bangladesh can be mitigated below the tolerate level. The governmental, non-governmental and private sector needs to be responsible and cooperative to keep our air lead toxicity free for us and our better future generations. The steps we can take are as like-Public awareness and behavior change including creating continual public education campaigns about the dangers and sources of lead exposure with direct appeals to parents, schools, community leaders and healthcare workers. Management, treatment and remediation including strengthening health systems so that they are equipped to detect, monitor and treat lead exposure among children; and providing children with enhanced educational interventions and cognitive behavioral therapy to better manage the negative effects of lead exposure.
(The writer is Chairman, Center for Atmospheric Pollution Studies and Dean, Faculty of Science, Chairman, Department of Environmental Science, Stamford University Bangladesh).
