The mystery of coloured water in Kalapara

Two liquid-filled bottles are positioned next to each other. The liquids are different, but the colour is almost the same. One gives off a stench similar to petrol when the caps are taken off and the bottles are placed close to the nose, the other is odourless. In reality, the odorless container contains drinking water. The yellowish, petrol-like water is what the residents of Kalapara in Patuakhali are surviving on.

It has been discovered that deep tube wells are the source of this unusually coloured water. The residents of Patuakhali's Kalapara upazila have been using this water for drinking, cooking, bathing, and other domestic tasks for many generations. They consider this colour of water to be its natural colour since they have grown so used to it. Moshtak Mia, a local, went so far as to say that he had never tasted freshwater as tasty as Kalapara's deep tube well water.

However, this ‘tasty’ water would surprise anyone who was visiting Kalapara for the first time. They would be reluctant to use it or drink it. Md. Ibrahim Hossain, assistant engineer, Department of Public Health Engineering (DPHE), Kalapara, is one such individual. He has been using this water out of need since taking over on 22 September 2024, but he is also looking for a solution.

"I am considering the state of the water," Engineer Ibrahim said to Prothom Alo. "I intend to speak with higher authorities about it shortly and take appropriate action." Although he is investigating the situation, he is unsure if this water presents any health dangers.

Researchers have identified the water in Kalapara as being straw coloured. They have attributed this colouration to the presence of chemical compounds called lignin or tannin. Lignin is an organic chemical component of plant cell walls. It originates from organic substances such as lignite coal or sub-bituminous coal.

These findings were revealed in a report titled "Root Cause of Groundwater colouration in coastal districts of Bangladesh: Findings from a preliminary study." The study was conducted by eight researchers from the World Health Organization's Public Health and Environment Unit, India's Ministry of Health and Family Welfare, Bangladesh University of Engineering and Technology (BUET), the Ministry of Local Government, Rural Development and Cooperatives, and the Department of Public Health Engineering (DPHE).

The research, conducted in 2021, was published in the UK-based journal Environmental Pollutants and Bioavailability. The researchers examined water from Kalapara in Patuakhali, as well as Sadar and Patharghata upazilas in Barguna district.

The average amount of lignin in the deep tube well water in these three regions ranges from 2.72 mg to a maximum of 5 mg per liter. The water also has an average of 0.12 mg of manganese, 1.67 mg of iron, 776 mg of sodium, and 39 mg of sulfate per liter. According to the study, water acquires a striking straw hue if the concentration of lignin surpasses 0.930 mg/liter and the total organic carbon surpasses 0.606 mg/liter.

According to the study, Kalapara indicates the strongest straw-coloured water in the three regions. The colour intensifies with the depth of groundwater extraction. This colouring is not present in shallow groundwater, which is between 0 and 18 feet. However, the colour's intensity begins to rise at depths of 721 feet and beyond.

Plants and animals may have been buried underground for thousands of years due to Eurasian tectonic plate movements. According to Professor Syeda Fahliza Begum, a geologist and water expert from Jahangirnagar University, lignin and sub-bituminous coal may have mingled with groundwater, She added.

"These chemicals may have mixed with deep groundwater in coastal areas like Kalapara due to tectonic plate movements and the slow deposition of sediment, However, much investigation is required to verify this." she told Prothom Alo.

Prothom Alo spoke with at least 15 residents of Kalapara to understand the impact of using the petrol-like yellowish water. Five of them reported that drinking this water had no negative consequences. However, the remaining 10 reported experiencing some sort of difficulty, such as hair loss, gastrointestinal difficulties, straw-colored urine, and itching. However, no one is certain whether these issues are directly caused by the water.

The most prominent complaint is persistent itching, reported by residents across several areas of Kalapara.  Alauddin Choukidar, from Kawar Char in Dhulashar Union, explained, "The itching is relentless.  I've also experienced a resurgence of gastric problems, which I suspect are linked to the deep tube well water, so I recently resumed drinking shallow tube well water."

Within 100 meters of Alauddin's house, an NGO installed a shallow tube well for everyday usage. All users are now drinking and using the water. Upon inspection, it was discovered that the water from the shallow tube well is colorless, exactly like regular water. However, Md. Jihad Hossain, Sub-assistant Engineer at the Kalapara DPHE, stated that the shallow tube well water in Kalapara contained arsenic. "It has not been possible to test all the tube well water in the area, but the ones that have been tested have been marked with red and green colors." He told Prothom Alo.

In November, over 8,500 people sought medical care at the outpatient department of the Kalapara Upazila Health Complex. According to the Upazila Health and Family Planning Officer, Shankar Prasad Adhikari, at least 2,500; or roughly 30%, sought treatment for itching. He stated, "Since joining this hospital, I've noticed an increase in patients with itching and allergy-related symptoms. We don't have a clear understanding of the major reason, but I assume it's the groundwater in Kalapara."

The previously mentioned study also highlights these health issues caused by the water. The researchers tested the water from 27 deep tube wells, nine from each of Kalapara, Barguna Sadar, and Patharghata Upazilas. They also conducted interviews with 81 people who regularly drink and use this water for other purposes.

The study mentions that, except for Kalapara and Patharghata, most of the interviewees from Barguna Sadar reported issues such as allergies, gastric problems, high blood pressure, urinary tract burning, diabetes, straw-colored urine, a sensation of heat, liver cirrhosis, and frequent bowel movements.

Shamsuddin Ahmad, Senior Chemist at the Barisal Zonal Water Testing Laboratory of the Department of Public Health Engineering, involved in the study, told Prothom Alo, "We tested the water and examined health impacts on a small scale, but didn't gain clear insights into specific effects. A larger-scale expert study is required, as well as additional research to determine why the chemical component (lignin) is combining with groundwater."

As plants grow, lignin builds up in their cells, strengthening them and forming the plant's wood structure. This makes the plant sturdier, helping it withstand challenges like insect attacks, fungal infections, and damage from the sun's harmful ultraviolet rays.

A study published in The American Journal of Clinical Nutrition states that lignin is not digested in the human stomach, small intestine, or large intestine. However, it may help prevent various metabolic issues. Lignin and tannins can be beneficial in regulating metabolism and cholesterol levels. The study from 1978 also notes that excessive intake of lignin can lead to digestive problems.

In addition, Piritta Niemi, a researcher from the Technical Research Centre of Finland, has explored the potential use of lignin extracted from wood in food production. Researchers Hasan Sadeghifar and Arthur Ragauskas have discussed the possibility of using lignin as a UV protection agent. They highlighted its potential in commercial products such as sunscreen, packaging films, varnishes, paints, antimicrobial protection, and even lotions and creams.

On the other hand, a New York-based company called Parchem has identified lignin as an irritant to the eyes in their Safety Data Sheet. The document also notes that if inhaled, lignin can cause physical discomfort, and in cases of excessive ingestion, it advises seeking medical attention.

However, no study directly discusses the harms or benefits of lignin. Almost all researchers on lignin have emphasized the need for further detailed research in the future.

Professor Tajuddin Sikder, from the Department of Public Health and Informatics at Jahangirnagar University, has conducted extensive research in Japan on the combination of plant-based organic chemical components in groundwater. He clarified that plant compounds like lignin and tannin do not stay in a certain state, which accounts for Kalapara's water's distinctive color. They change and react with other substances over time.

While analysing compounds that leach from plants into the water, Professor Tajuddin Sikder noticed the presence of humic acid during his 2011–12 research on groundwater in Indonesia’s peat forests. "Over time, different plant components mix with groundwater, resulting in chemical changes that form humic acid," he explained. The human body is extremely poisoned by humic acid.

"Since plant chemicals like lignin have dissolved into the groundwater in Patuakhali, there is a need for detailed research to determine whether chemical reaction reactions in the water might create any toxic effects," He Added.

Although people were previously unconcerned about the color of the water, in recent years, conscious Kalapara locals have grown more aware. They believe that water needs to be purified for drinking and cooking.

In November, Fatema Heren joined as the Principal of Kalapara Government Mozahar Uddin Biswas Degree College. After joining, she promptly turned off the deep tube well and installed a water purifier. Fatema Heren told Prothom Alo, "The first thing that struck me when I arrived in Kalapara was the water. Seeing its colour, I didn’t use it at first. I started buying bottled water and later installed a water purification system."

A few years ago, there was little requirement for water filters in Kalapara. However, for the last five to six years, people have been buying these devices. Water purifiers are being marketed in seven to eight businesses around the Kalapara Municipality. However, Anas Corporation is the shop with the biggest sales. This shop, located on the ground floor of the Kalapara Press Club building, opened two years ago. According to shop owner Zakir Hossain, over 300 water purifiers have been sold in the last two years.

Professor Fatema Heren stated that "Everyone needs to be aware of water-related issues because the colour of this water is not normal." She believes it is not wise to continue drinking and using this water without finding a solution. She also believes that assistance from appropriate government departments is required in this problem.