Each week, families in the six special municipalities carry home more than 220 million pieces of plastic from 10 major retailers, a study released by Greenpeace Taiwan on Tuesday showed.

Ninety-one volunteers from 36 families — six in each city — participated in the week-long study, the environmental group said, adding that the size of the families varied from one to three members.

It said that for one week, the volunteers took photographs of the plastic items and packaging bought while shopping at one of more of the following outlets: PX Mart, Carrefour, Carrefour Market, 7-Eleven, FamilyMart, RT-Mart, Costco, A-Mart, Wellcome and Simple Mart.

On days when they did not purchase anything, they submitted blank photographs, it added.

In that week, the 36 families carried home a combined 493 plastic bags, plastic film, plastic boxes, plastic trays and plastic mesh bags, which, if extrapolated for all families in the cities, would translate to about 88.1 million pieces, Greenpeace said.

Based on data provided by the volunteers, every week families in the six cities also take home about 23.56 million plastic cups, caps and straws, about 24.75 million plastic bottles, 18.94 million extruded polystyrene foam products and 66.67 million miscellaneous plastic packaging items from brands not owned by the retailers, adding up to more than 220 million items, it said.

Greenpeace said that it hopes the retailers will establish plans to reduce the amount of plastic waste generated by their businesses.