Seven rivers in Jakarta and two rivers in its satellite cities of Tangerang, Banten, and Bekasi, West Java, are polluted by trash, dumping 21 tons of waste daily into Jakarta Bay, a researcher has calculated.

The seven rivers include the Angke, Sentiong, Sunter, Cilincing and Marunda. Meanwhile, the two rivers in the satellite cities that flow into Jakarta Bay include the Dadap in Tangerang and Bekasi in Bekasi.

"Of the seven rivers in Jakarta, one river in Bekasi and one river in Tangerang, the total waste that enters Jakarta Bay is 21 tons daily," said Reza Cordova, a sea chemical and ecotoxicology researcher from the Indonesian Institute of Science’s (LIPI) oceanographic research center.

According to Reza, most trash that flows into Jakarta Bay comes from Jakarta's sister cities because the trash management in Jakarta's rivers is "well-managed".

"Waste in Jakarta is relatively less severe than those of Tangerang and Bekasi because there is a possibility that waste management in Jakarta is one of the best [compared to Greater Jakarta]," Reza said as quoted by wartakota.tribunnews.com on Monday.

Reza added that the work of Jakarta's Public Facility Maintenance Agency (PPSU) personnel, popularly known as the "orange troops", contributed to the better waste management of rivers in Jakarta.

"On average there is less that 1 ton of trash per day. In Tangerang and Bekasi, [the trash can reach] up to 7-8 tons per day," he said.

The trash that goes into Jakarta Bay consists of wood, glass and mostly single-use plastic. (mai)