Indiscriminate use of toxic chemicals to grow, ripen and make fruits and vegetables appear fresher or even last longer adds to the worries of the residents of the capital on top of spiralling prices of these commodities.

Banana, everyone's favourite fruit, arrives in tonnes at the Sadarghat river terminal before dawn everyday. Piled up high in the hold, the bananas are dark green in colour and taste quite bitter. Amazingly enough, later that same afternoon, those very bananas would transform into flavoursome yellow appetisers.

"We use a 'medicine' to help the bananas ripen faster and get a nice yellow colour," said a wholesaler. "I am not sure about the name of this chemical, but it works like magic. If you ask for the 'medicine' to ripe bananas, you can get it from any pharmacies around Dhaka Medical College Hospital (DMCH) and Mitford Hospital," he added.

Later, a visit at a pharmacy near DMCH revealed that the cheap and widely available chemical used to ripen bananas is in fact Calcium Carbide. It is an extremely hazardous substance for humans as it contains traces of arsenic and phosphorous.

When dissolved in water, carbide produces a substance known as acetylene gas, which manipulates and accelerates the ripening process. Greener the produce is, the more carbide is required to effectively ripen it -- resulting the fruit to lose taste and turn more toxic.

Like bananas, toxic chemicals are being applied on tonnes of other produce each and everyday to make them appear fresh and ripe. Almost 80 per cent of the organic produce including fruits and vegetables that flood the market and allure people with fresh looks are tainted with toxic substances posing grave danger to the public health, said health experts.

"Farmers use toxic pesticides containing Organo Chlorinate, Mercury, Lead, Organo Phosphate and numerous other hazardous poisons to ensure maximum production all year long, said Golam Sarwar, public analyst of Public Health Laboratory (PHL) under Dhaka City Corporation.

"Synthetic colours, dyes and other chemicals used in the adulteration process destroy the nutritional substances inside the produce," said Dr S Borua, nutritionist at Bangabandhu Sheikh Mujib Medical University (BSMMU).

"Ingestion of these poisonous chemicals through fruits or vegetables may cause various diseases including diarrhoea, dysentery, infertility, skin cancer and even death," added Dr Borua.

According to a study by Bangladesh Agriculture Research Institute (Bari), toxic chemicals are being widely used to enhance the production of vegetables.

The bari study was conducted at Shakhipur and Ghatail in Tangail where farmers and traders admitted of using toxic chemicals and pesticides frequently to make a quick buck without knowing that these chemicals have a negative impact on humans if scientific methods are not used and necessary precautions are not taken.

Traces of toxic chemicals and pesticides can be found in the produce even four months after these are applied on. Alarmingly, most produce reach the kitchen markets in Dhaka within only three to four days after pesticides applied on them. The deadly elements exist within the vegetables even after these are cooked. World health organization graded the pesticides into three different categories in terms of intensity of poisonous effect -- Hu-1, Hu-2 and Hu-3. Hu-1 grade pesticides, extremely hazardous to human and other mammals, are primarily used to kill poisonous snakes and deadly insects that live in tea or rubber plantations. Hu-2 grade is less poisonous while Hu-3 is the least. The agriculture ministry of Bangladesh banned the use of all of these three grades of pesticides on fruits and vegetables in the country.

According to newspapers, besides using locally manufactured pesticides, farmers also tend to use banned and highly poisonous Indian pesticides for its cheaper price. The most popular Indian pesticides are Thiodin, Hildon, Ostad and these are all of Hu-1 grade.

Bangladeshi farmers have been using Hu-1 grade pesticides without much restriction and it is available in markets all over the country.

"Indian pesticides don't require frequent use, spraying them only a couple of times would do wonders," explained PHL public analyst Golam Sarwar. "Since these pesticides are not required to be used frequently, the cost associated with them is much lower.

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Agriculture ministry officials told this correspondent that use of any kind of pesticides on vegetables is prohibited. They however expressed ignorance on the availability of Thiodin or any other Indian pesticides in markets.

"If proven, stern actions would be taken against any offender," said Saiful Islam, an official at the agriculture ministry.

"Instead of using chemicals in agriculture that is hazardous to the public health, using Neem leaves or Neem juice could be as effective as any pesticides. This would also keep the produce wholesome," Islam recommended.