A long history

Alkaline batteries are used in a wide range of household items, including remote-control handsets, digital cameras and toys. They have a longer history and greater influence than any other type of battery, such as the lithium-ion variety used in cellphones, nickel-hydrogen batteries in hybrid electric vehicles and lead-acid cells in electric bikes.

Since 2004, China has been the world's largest producer of batteries, and in 2014, the nation's annual production of alkaline batteries reached 13.8 billion, according to statistics from the China Industrial Association of Power Sources, an industry association.

Many people are enthusiastic about collecting spent alkaline cells because of the widely held belief that they contain toxic chemicals that can contaminate the soil and underground water supplies if they are simply thrown away.

According to some scientists, one AAA alkaline battery has the capacity to pollute 1 square meter of soil, while one button cell (the flat batteries used in many types of camera) could pollute 600 tons of water, roughly equal to the amount each person consumes in a lifetime.

The public impact of the reports were highlighted by Beijing News, which spoke to Ming Wenyou, a watch repairer in Beijing, who said he has never discarded a single battery, and has stored more than 10 kilograms of them for three years.

Xu Haiyun, chief engineer at the China Urban Construction Design and Research Institute, said alkaline batteries contain toxic metals such as mercury - which can be especially dangerous to children's developing nervous systems - and other chemicals that leech into the soil, "but it's an exaggeration to say the chemicals cause soil and water pollution in that way, especially as China has seen great improvements in technology to reduce the toxic content."

When interviewed by China Environmental Daily, Wang Qi, head of the Institute of Solid Waste Pollution Control Technology at the Chinese Research Academy of Environmental Sciences, supported the concept that batteries cause minimal pollution, and cited an experiment conducted by Fukuoka University in Japan.

Researchers from the university buried alkaline batteries containing mercury in a landfill site for 20 years. Tests conducted later showed that the small amount of mercury that had leaked out was well within the soil's bearing capacity, and indicated that dumping batteries does not cause soil pollution.

Additionally, China has improved technologies to produce non-mercury batteries, and in 2006 outlawed the sale of cells containing more than 0.0001 percent mercury.

All batteries manufactured by legally registered companies comply with the national standards, according to Qian Jing, secretary general of the battery division of the China Industrial Association of Power Sources, who said illegal batteries are only being made in a small number of unregulated factories.

In recent years, technological improvements have reduced levels of mercury in batteries and national guidelines have been introduced that contain stipulations on the disposal of spent batteries, moves that have resulted in calls for collection and recycling to be phased out, and for batteries to be disposed of along with general household waste.

"The guideline does say they can be discarded, but the precondition is that there is no capability to recycle them," said Wang Zixin, the storage facility owner.