Arsenic attack on Chittagong

People in the port city depend on arsenic-contaminated groundwater in absence of safe water supply

Published on:

10 Nov 2012, 6:58 am

Driving across Bangladesh’s port city Chittagong, one sees red marks on several tubewells. A closer look reveals red and scaly patches all over the body of most people living in the vicinity of those tubewells. Common among the poor and those living in slums, the skin disorder is the initial symptom of arsenic poisoning.

Arsenic is a heavy metal found naturally in the earth’s crust. At places, it mixes with groundwater, contaminating food crops and causing alarming threats to the health of humans and livestock. Prolonged ingestion of arsenic-contaminated water can result in health complications, ranging from gangrene to skin cancer. The concentration of arsenic is high in Chittagong’s shallow aquifers. As the city lies in the low-lying floodplains of Bangladesh, water remains stagnant here and the fine-grained silt and clay rich in arsenic gets deposited in the shallow aquifers, says Kazi Matin, professor of geology at Dhaka University.

Two-thirds of the city’s 5.5 million population depend on groundwater. Seven of the 41 wards under the jurisdiction of the city corporation have high arsenic contamination (see graph), according to a study by Chittagong University of Engineering and Technology (CUET) in association with Chittagong Engineers Institute and the Bangladesh Environment Forum.

Arsenic-affected wards in Chittagong

Swapan Kumar Palit, professor at CUET, says the Water Supply and Sewerage Authority (WASA) supplies water to only to one-third of the city population. As digging deeper tubewells and borewells is expensive, the poor and slum dwellers have to rely on shallow aquifers. The arsenic contamination levels is thus taking a toll on the unprivileged.

According to the WHO guidelines, the permissible limit for arsenic in water is 0.01 ppm. Going by this standard, 60 of Bangaladesh’s 64 districts are arsenic contaminated. The country, like its neighbour India, has, however, set its standard at 0.05 ppm. The study by CUET found that arsenic contamination is high in several areas both by the standard of Bangladesh and WHO.

Arsenic’s health impact

Prolonged drinking of water highly contaminated with arsenic can cause arsenicosis, which is a chronic pathological disorder, resulting in cancer and untimely death. Apart from health issues, arsenicosis also diminishes the ability to work and results in social exclusion for the person suffering from the skin disorder.

A research paper from the medical college of Chittagong shows the district has the second highest number of arsenic affected patients, the first being Noakhali. According to the researchers, arsenic spreads through the body tissues in the blood, hair and nails of the humans. The first symptoms may be raindrop pigmentation or mottled pigmentation on the exterior body parts.

Hyper-keratosis is a stage which appears after a prolonged period of consuming high amount of arsenic. Initially, a patient may suffer from dermatitis, hyperkeratosis, conjunctivitis, diarrhoea, anaemia, peripheral neuropathy and, eventually, multiple organ failure. The patient may suffer gangrene of limbs and even skin cancer in the long run.

rainwater harvesting