Expressing concern over the incidents, Chief Minister Nitish Kumar said: "I am really worried as after the contaminated mid-day meal tragedy, now reports of poison being mixed in handpumps at schools are coming in from various places."
All the children have been hospitalised for treatment.
"After initial treatment at a nearby primary health facility, all children except two were referred to PMCH (Patna Medical College and Hospital) for treatment following an order from the chief minister. The two children were admitted to the Sadar hospital in district headquarters town of Saran," an Saran district official said.
In Gopalganj, all the six children were admitted to a government hospital.
According to officials, the children complained of pain in the stomach and started vomiting soon after drinking water from the handpump.
As the news of the children having taken ill after drinking handpump water spread, hundreds of villagers from Maulanapur staged protests by blocking roads and damaging government vehicles, the police officer said.
District Magistrate Abhijeet Sinha and Superintendent of Police Sujeet Kumar visited the hospital and the children were shifted to Patna Medical College and Hospital.
Sinha, who rushed to the village after being informed about the incident, had to face the protesters' ire as they forced him to return without visiting the school.
Twenty-three students of Dharmasati Gandaman primary school in Saran district had died after eating poisonous midday meal on July 16.
Another four students fell ill after drinking contaminated water from a tube well in a government school under Kauchaikot block in neighbouring Gopalganj district during the day.
Two other persons who drank from the well to fell ill, official sources said.
150 students had fallen ill on Wednesday after eating midday meals at two schools in Jamui and Arwal districts of Bihar.
While 55 students of a government middle school fell ill after eating midday meal provided by an NGO at Kalyuga village in Jamui district, 95 others of Chamandi primary school in Arwal fell ill after the meal.