After an electrical conductivity test, Department of Environment officials confirmed what the locals have been saying.
They said the sudden rise in salinity may have been caused by reduced water flow from upstream and lower rainfall.
The Kirtonkhola is now another in a list of over 100 rivers flowing through the coastal region and affected by salinity due to sea water intrusion.
Saline river water also results in salinity in the groundwater which in turn increases the level of soil salinity. And that causes a significant reduction of vegetation in the affected areas, experts say.
Around 25-30 percent of the country s arable land is located in 21 coastal districts, of which 53 percent has become saline-affected, finds a recent study by Khulna University.