The Kirtankhola River is 21 kilometer long from Shaistabad in Barisal to Nalchity in Jhalokati. Going to Nalchity, the river has flowed into the Bay of Bengal through Bishkhali River.
The river is 130 km away from the Bay of Bengal and considered as a ‘protected reservoir’ of freshwater for this region (southern region). Last February, the electrical conductivity (EC) of this river water was about 300 to 400 micro Siemens per centimetre. But in March this rate increased dramatically to 1,362 micro Siemens per centimetre.
This data was collected from the Soil Resource Development Institute (SRDI), Regional Office, Barishal and the Department of Environment and the Water Development Board. These agencies regularly monitor the water quality of rivers in the region.
Soil and agricultural experts say that EC is a measure of water salinity. The acceptance level of salinity in water is 750 micro Siemens per centimetre. But the river’s water in Barishal contains much more salinity than the acceptance level.
This salinity has spread over more than 150 km of upstream in the rivers of the southern coast including Barishal. Its effects are beginning to be felt in agriculture, environment and public health.Public health experts held the salinity of water responsible for the recent outbreak of diarhoea in Barishal region. The quality of the water, soil and environment of the entire southern coast is being changed due to the effects of drought, searing heat waves and abnormal salinity in the rivers.
Like Kirtankhola River, in April, the salinity level of Bishkhali River in Barguna was 2,084 micro Siemens per centimeter while the level was 3,071 micro Siemens against every centimetre of Lohalia River in Patuakhali.
On the other, the salinity was 12,080 micro Siemens in the Amtali section of the Payra River and 14,040 Siemens in the Charduani section of the Baleshwar River.
Experts say that the characteristics of Barisal’s soil, water and climate are different from other coastal areas since it is surrounded by numerous rivers and canals. Even in the dry season, the saline water of the sea could not enter these rivers as there was sufficient flow of fresh water from upstream.
However, in the last few years, salinity, drought and heat waves have begun to have an adverse effect on these rivers. All of a sudden, this change has been accelerated and the salinity level flowed upstream after entering the protected area.
The level of salinity in Kirtankhola River was 440 micro Siemens in 2018 compared to 404 in 2019. That level sustained in 2020 too. At Meghna-Surma point in Tazumuddin area of Bhola, this level was 1,298 micro Siemens in March 2018. But it increased to 2,221 micro Siemens in March 2020.
In March 2018, the level of salinity at Betagi Point of Bishkhali River in Barguna was 1725 micro Siemens. At that time in 2020, the level was 1,587 micro Siemens against each centimetre.
Chief Scientific Officer of SRDI, Barishal regional office, Sabbir Hossain, told Prothom Alo that the matter of raising the salinity level to the upstream is a bad omen for us. He thinks that drought, hot temperature and the reduction of upstream water flow have played a vital role to create this situation.
Temperature rising
According to the Meteorological Department, the maximum temperature in Barishal in February this year was 34 degree Celsius even though it was forecasted to be 28.2 degree.
In March this year, the temperature was expected to be 32.2 Celsius but it was appeared actually at 36.7 degree. In April, temperature was 35.7 degree instead of 33.4 degree as forecast by the meteorologist. However, the temperature felt by the people was above 40.
Similarly, in January 2020, the maximum normal temperature in Barishal was supposed to be 25.6 degrees Celsius. But on 15 January, the maximum temperature was 26.5 degree Celsius. On 16 January, it reached at 28.6 degree Celsius. And on 17 January, it rose further to 30.6 degrees, which is 5 degree higher than normal.
Lower rainfall than forecast
As a result of such abnormal temperature, the character of six seasons is gradually fading in the coastal areas including Barishal. Warming has had a greater impact on rainfall.
According to the Meteorological Department, in the four months from January to April this year, the rainfall was expected to be around 230.17 mm but it was recorded only about 1.3 mm, which was 99.5 per cent less than normal range of raining.
Even in 2019, there was no normal rainfall in this region. The average rainfall in June-July was forecast to be at 815.07 mm but actually it was 592.10 mm. Normal rainfall in August-September was recorded at 436 mm which was expected to be at 530.4 mm.
Adverse impact on agriculture and public health
Despite various limitations, rice production in Barisal division has been increasing for several years. Last year, the division produced about 3.1 million tonnes of rice. Similarly, 80 per cent of mug dal (lentils) and 65 per cent of watermelon are produced in this division.
But the cultivation has been affected by continuous heat wave, drought and the salinity. Thousands of hectares of Boro, moong dal and Robi crop fields have already been burnt in the continuous searing heat. The Department of Agriculture has calculated the losses.
Alimur Rahman, chief scientific officer of the regional office of the Agricultural Research Institute, said, “Once the land becomes saline, it is not easy to reclaim. No matter how tolerant the variety of crop may be, it will not work. Eventually, production will decrease. So we need to take a collective decision quickly on how we can prevent salinity aggression.”
Not only agriculture, Barishal region has been supplying 66 per cent of the total hilsa fish of the country for several years. Apart from this, the division also contributes a lot in the production of freshwater fish. Due to the increase in salinity in the rivers, there is a danger that the breeding and growth of freshwater fish including hilsa will be hampered.
The outbreak of diseases along with diarrhea intensifying
High levels of salinity are affecting public health in the region. The Community Health and Hygiene department of Patuakhali University of Science and Technology conducted a research in June 2018, funded by the Ministry of Science and Technology.
A total of 100 women, who have children under the age of five, from the two unions of Kalapara upazila in Patuakhali were first surveyed.
Water from deep tube wells, ponds, canals and the urine samples of the women, who took part in the survey, were collected and tested in the university laboratory.
Sample tests show that 58 per cent of women are consuming more than 2 grams of sodium per day, as prescribed by the World Health Organization (WHO). Surprisingly, the salinity of tube well water is higher than that of pond water. The salinity of deep tube well water is 2220 micro Siemens per cm while it is only 410 in the pond water.
According to the standards set by the WHO, the tolerable sodium level in the deep tube wells of the area is 697 micro Siemens and the pond is 134 micro Siemens. This high salinity of water has a visible effect on the urine and blood pressure of these women.
There is no awareness among women participating in the survey about the health effects of high levels of salinity. They only know about a handful of diseases, including gastritis, skin diseases, rheumatism and high blood pressure.
However, some respondents mentioned a number of health problems in the survey, including bladder inflammation, painful urination, gynecological problems, bleeding and premature abortion, cardiovascular disease, asthma and allergies.
Besides, another section of participants mentioned typhoid, piles, fatigue, thyroid, stroke, cold, toothache, diabetes, eye problems and anaemia as their diseases.
According to a World Bank report published in 2013, the amount of increased salinity in water has been linked to a growing number of diarrhoea cases. The report also said that the long-term survival of the cholera bacterium ‘vibrio cholerae’ in saline water can lead to frequent cholera outbreaks.
According to the health service division, the outbreak of diarrhoea appeared in the region on 1 January this year. From that time to 26 April, more than 40,000 people have been infected with diarrhea. Of them, nearly 10,007 people have been infected only just six days from 20 to 26 April.
According to the government statistics, totaled 11 people have died of this disease in April. But the number of deaths is more than 30 as per the statistics of private organizations.
Associate professor of the department of community health and hygiene at Patuakhali Science and Technology University, Liton Chandra Sen, told Prothom Alo that research has shown that salinity can cause high blood pressure, pre-eclampsia, and many other health problems on the coast. Its effects on diarrhoea have not yet been studied. However, due to drought and heat wave, rivers and ponds dry up resulting to increase the level of salinity among the sources of water.
He added excessive heat causes dehydration in the human body, resulting in imbalance of sodium and potassium. This insufficiency kills the beneficial bacteria in the body and reduces the digestive power that led the people to drink any type of water as they have a strong thirst. As a result, salinity may indirectly cause diarrhoea.
* The report, published in print and online edition of Prothom Alo, has been rewritten in English by NH Sajjad