Environmental group rubbishes stats used by Government to estimate impact of plastic bags

Thursday, 6 July 2017

Sam Judd from Sustainable Coastlines cleans up Lower Hutt's Petone Beach.

Kiwis use 673 million supermarket single-use shopping bags every year - enough to cover half of Otago if laid flat - according to new research.

Sea Life Trust conducted the study for Plastic-free July, and found plastic shopping bags were the most commonly used single-use plastic item.

Other offenders included the 541 million straws thrown away every year, 309 million coffee cups, and 105 million single-use bottles.

The study's plastic bag figures painted a different picture to those used by the Government to determine their environmental impact.

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Previous industry-led research, which the Government used to inform policy making, estimated that bags account for 1.5 per cent of litter nationwide, and 0.2 per cent of the waste stream.

Figures from Sustainable Coastlines, an organisation focused on marine protection, also suggested the Government underestimated the impact of plastic bags.

The organisation has collected over 1.2 million litres of rubbish over eight years.

CEO Sam Judd said figures from clean ups estimated 77 per cent of marine waste came from single-use plastics, and plastic bags were the fourth biggest contributor.

Associate Environment Minister Scott Simpson said it was common for the Government to rely on industry data for decision making.

'There is a lack of independent data around litter. The only data that's being used at the moment is from studies commissioned by the Packaging Forum,' he said.

'It is commissioned by industry, who have a vested interested in selling packaging.'

Judd said soft plastics were dangerous to marine animals, which would often eat them or become entangled.

The Ministry of Environment has not conducted any research on plastic bags, instead relying upon data produced by industry groups.

These included a national litter survey from the Packaging Forum, which found plastic bags accounted for 1.5 per cent of litter, and research from the New Zealand Packaging Council from 2009, which estimated bags made up 0.2 per cent of the overall waste stream.

Judd criticised the Plastics NZ figure, on the grounds it was based upon weight. If it were based on volume, he said, the proportion would be far higher.

Friends of Owhiro Stream coordinator Martin Payne said a recent clean up of a 300-metre stretch of the Wellington waterway collected 80 kgs of soft plastics and polystyrene. He agreed weight was not a practical measure.

Consulting service Waste Not Consulting conducted the Plastic Forum litter survey. Director Bruce Middleton defended the methodology but acknowledged it may have downplayed the impact of plastic bags.

The study counted all items bigger than a bottle cap and divided them into categories, meaning percentages of overall waste were based on numbers, rather than size, or visual impact.

Associate Environment Minister Scott Simpson said it was not unusual for the Government to use industry research to inform policy decisions.

The Government had just allocated funding for the first independent national litter survey, he said.

Forty eight of the country's 67 city and district mayors have now signed an open letter calling for a plastic bag levy.