Toxic metals in the soil threaten our food and health

Soil is not just dirt beneath our feet-it is the foundation of life on Earth. Healthy soil helps grow food, supports biodiversity, and plays an important role in human health. But in Bangladesh, soil pollution has quietly become a serious national problem. Many people are not aware, but the land that grows our food is becoming toxic day by day.

According to the Department of Environment's 2023 report, 45% of agricultural land in Bangladesh is polluted by harmful heavy metals such as lead (Pb), cadmium (Cd), arsenic (As), chromium (Cr), and nickel (Ni). These are found in amounts that are 3 to 8 times higher than the safe level for humans. This pollution is not only lowering food production, but it is also harming people by entering the food chain. A 2021 World Bank report showed that lead pollution alone causes a drop in IQ for about 35,000 children in Bangladesh each year.

This column explains where soil pollution comes from, how it affects health, the failure of environmental policies, and what we can do to solve the problem. Industrial waste and tanneries: The rapid growth of factories has had a negative impact on the soil. Every day, industries such as copper factories in Narayanganj, tanneries in Savar, and textile mills in Gazipur release over 20,000 liters of untreated waste into rivers and soil. Tanneries release extremely high amounts of Chromium-6-between 5,000 and 7,000 milligrams per kilogram-while the safe limit set by the World Health Organization (WHO) is just 0.05 milligrams. A 2022 survey by the Department of Environment found that 90% of agricultural land near the Hazaribagh tannery zone has unsafe levels of chromium.
Overuse of chemical fertilizers and pesticides: Research from the Bangladesh Agricultural Research Institute (BARI) in 2022 showed that urea fertilizer use has increased by 300% in the past 20 years. Phosphate fertilizers contain cadmium, which contributes to soil pollution. Moreover, about 60% of pesticide chemicals remain in the soil and eventually enter crops.

E-waste and vehicle emissions: Dhaka city produces around 400,000 tons of electronic waste each year from old mobile phones, batteries, and computers. Only 5% of this is recycled. When e-waste is burned, it releases harmful substances like lead, mercury (Hg), and cadmium into the air and soil. Also, smoke from vehicles releases lead particles that settle in urban soils.

“E-waste and vehicle emissions: Dhaka city produces around 400,000 tons of electronic waste each year from old mobile phones, batteries, and computers. Only 5% of this is recycled. When e-waste is burned, it releases harmful substances like lead, mercury (Hg), and cadmium into the air and soil. Also, smoke from vehicles releases lead particles that settle in urban soils.

Developmental problems in children: According to Dhaka Medical College Hospital, about 40% of children in the capital have lead levels in their blood that are equal to or higher than the WHO's safe limit of 5 micrograms per deciliter. Lead affects the nervous system and reduces IQ by 5-10 points. It also increases the risk of autism. The World Bank says that lead pollution causes an economic loss of $15.9 billion in Bangladesh each year.

Genetic damage and food insecurity: Environmental scientist Dr. Mahbubur Rahman says that heavy metals react with human DNA and cause mutations. These may lead to birth defects like spina bifida in the next generation. Crops grown in polluted soil also have less zinc and iron, which can cause hidden hunger and malnutrition.

Policy Gaps: Laws Exist, But Enforcement Is Weak: Bangladesh has several laws to protect soil, such as the Environment Conservation Act (1995), the National Environmental Policy (2018), and the Soil Health Act (2021). But in reality, these laws are not properly enforced. For example, when tanneries were moved from Hazaribagh to Savar, about 60% of them started operations without Effluent Treatment Plants (ETPs). A 2023 report showed that nearly 50% of industrial facilities are operating without environmental clearance.

Local Government Limitations: Union Parishads do not have enough data, training, or tools to monitor soil pollution. NGO surveys found that 70% of farmers do not even get the chance to test their soil. Without testing, they cannot know whether their land is polluted or not.

Solutions: Science, Policy, and Public Awareness: Bioremediation and phytoremediation: BARI soil scientist Dr. Farida Yasmin led a pilot project in Mirpur using sunflower and Indian mustard plants to clean polluted soil. They were able to remove up to 40% of chromium. Also, mycorrhizal fungi are helpful in absorbing heavy metals from the soil.

Organic farming and nanotechnology: Organic fertilizers help increase soil pH, which reduces the solubility of heavy metals. In the Netherlands, scientists used nano-iron particles to remove 90% of arsenic from soil. Bangladesh needs more funding for research to use such technologies.

Policy reforms: Use real-time IoT sensors to monitor factory waste. Give subsidies to farmers for organic fertilizer and useful plants. Create a strong e-waste management system like Singapore's recycling model.

International Examples: Japan created a strong environmental law in 1970 after the Minamata pollution disaster. Today, they use AI-based machines to clean soil. The Netherlands has set a goal to make 50% of its farmland organic by 2030.

Soil pollution is more than an environmental issue and it is a threat to national security. Around 62% of Bangladesh's population depends on agriculture. If the soil becomes poisonous, the whole nation will suffer. To prevent this future, we must act now-with better laws, modern technology, and strong public awareness.

The writer is a student, Department of Environmental Science, Bangladesh University of Professionals