As the globe marks World Soil Day on Sunday, Dec. 5, the presence of heavy metals and pollutants in Bangladesh's soil along with its lack of necessary nutrients are having a direct impact on the country's life, agriculture, and the environment.
Soil health is deteriorating mainly due to the excessive use of chemical fertilizers, rising salinity, use of topsoil in brick kilns, industrial pollution, deforestation, petroleum lead air pollution, and deposits of electronic and medical wastes in the soil, said experts.
The presence of 5% organic matter in soil is best, while it requires a minimum of 2%. But it has now come down to less than 2% in Bangladesh, say recent studies.
Bangladesh is among the most polluted countries in the world, with all the major rivers in the capital, Dhaka, so polluted that the water cannot even be purified.
Public health also remains at high risk due to the entry of harmful substances into the body through the food cycle.
A study by the Bangladesh Soil Resource Development Institute recently found that a lack of organic matter and the reduction of various nutrients are behind declining soil fertility.
The Bangladesh Atomic Energy Commission and two public universities recently found cobalt at 38 times higher than tolerable levels and chromium at 112 times higher, along with 11 heavy metals.
According to a study by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystems, worsening land degradation caused by human activity is undermining the well-being of two-fifths of the world’s population, or around 3.2 billion people, driving species extinctions and intensifying climate change.
-Industrial pollution, sewage damaging land
Ahmad Kamruzzaman Majumder, head of the Environmental Sciences Department at Dhaka’s Stamford University, told Anadolu Agency that industries, sewage waste, and agricultural fertilizers are directly polluting land and damaging soil nutrients.
“Soil can recycle the fertilizers but can’t recycle industrial waste. Thus, the topsoil is being seriously damaged and becoming lifeless due to industrial pollution,” he said.
Brick kilns are another major polluter that directly causes damage. On average, they take away 800,000 tons of topsoil daily, which is also taking away land for cultivation.
“Soil, water, and air pollution are correlated and are polluted like a cycle,” said Majumder, who is also founder and director of the Center for Atmospheric Pollution Studies.
“Contaminated air and water are ultimately stored in ground soil. And, such damage not only causes immense harm to agriculture but also to other plants and microbes.”
He said teams have found a high presence of heavy metal and lead in the soil in the capital Dhaka and the city of Khulna.
“There are some one million lead battery-run auto rickshaws operating in Bangladesh. These lead batteries need to be replaced every six to eight months due to the lack of lead recycling in Bangladesh,” he said.
The waste in sewage lines of city apartments in most cases is linked to rivers and waterbodies, and to deaths of helpful microbes in river water, riverbeds, and topsoil, said Majumder, who is joint secretary of the Bangladesh Environment Movement (BAPA).
He said Bangladesh must ensure the use of effluent treatment plants in industrial areas, stop the use of topsoil in traditional brick, and promote the use of environmentally friendly bricks instead.
Bangladesh decided to phase out the use of bricks by 2025 in all construction as it remains the major source of air and soil pollution in the country.
The soil in big cities like Dhaka has largely lost fertile capacities and is becoming lifeless due to a lack of nutrients and friendly microbes.
-Weather, crop intensity cause low fertility
Bidhan Kumar Bhander, head of the government’s Soil Resource Development Institute, told Anadolu Agency that attaining the presence of 5% organic matter is quite hard from the perspective of the country’s weather.
“The average temperature of countries like Bangladesh is higher compared to temperate countries like Europe. In summer, our soil gets burned, losing chemical composition and nurturance,” he said.
Two to 3% is considered good for Bangladesh, said the government soil expert.
“Over the years we’ve increased crop production, which causes the soil fertility to go down. In the 1970s the crop intensity rate was 117% and has now reached about 200%. Therefore, we have to ensure the use of balanced fertilizer in soil before cultivation,” he said.
One million hectares out of 2.8 million hectares of farming land in coastal Bangladesh contains salinity.
“We prepared those salinity-driven soil for fishing enclosure. And we started using soil technology called topsoil carpeting to replace topsoil in coastal regions by importing fertile land,” he explained.
“Now farmers have started getting the benefits of it and making a profit by cultivating crops.”
As the government provides subsidies to fertilizers, some unscrupulous traders contaminate it to make a profit. The contamination sometimes contains heavy metals. However, the institute regularly monitors markets, running assessments and tests for contamination.
Bhander stressed the use of modern technology instead of traditional methods in brickfields as well as the use of effluent treatment plants in factories.