Several suspects have been held for allegedly dumping garbage along Yangtze River, threatening the water source on Chongming Island, the city's watchdog said yesterday.
The maritime authorities of Shanghai and neighboring Jiangsu Province found two ships suspected of dumping large amounts of household waste from upstream of the river, Shanghai Environmental Protection Bureau said.
Shanghai and Jiangsu police have launched a joint investigation.
A massive load of garbage has floated onto the northern bank of the island, with much of it accumulated near Dongfengxisha Reservoir, one of Shanghai's four major water sources and which supplies drinking water to 700,000 Chongming residents.
The reservoir had not been polluted and tap water on the island was safe to drink, Shanghai Water Authority said.
The authority has tested the water quality of the reservoir, which has stopped taking in water from the Yangtze. The city's maritime safety administration has also enhanced patrols around the reservoir.
More than 17,000 packs of floating garbage had been salvaged near the reservoir since Saturday, said Song Jian, deputy general manager with the island's water source management company, which is in charge of the garbage collection. Most of the garbage was household waste, including broken bottles and cans as well as clothing and quilts.
More than 40 workers have been salvaging the garbage from the riverbank. All the rubbish is expected to be cleared around the reservoir in two weeks.
"Much garbage has been floating into reed marshes near the reservoir, which had increased the difficulty of clearing them," Song added.
The first batch of floating garbage appeared about 2 kilometers away from the reservoir on November 5, said Song.
Chongming water authority then carried out the garbage collection campaign and had salvaged more than 100 tons of garbage in a total of 48,100 packs by the end of November.
Some medical waste, such as needles and plastic tubes, were found in the garbage, he added.
The floating garbage reappeared near the reservoir on Saturday morning, when the salvage efforts were relaunched.
Upon the completion of the salvage work, the authority would carry out another round of water quality tests in the reservoir, Song said.
No garbage had yet been found near the downstream Qingcaosha Reservoir, which is the city's major tap water source and supplies water to all downtown residents, the city's water authority said.
The authority has enhanced patrols around Qingcaosha to salvage any floating garbage.