Green claims for plastic pouch based on Swiss data

Plastic pouches are being given a marketing push by packaging producer Linpac amidst claims that their environmental impact is only half of that of their closest rival. But the claims are based on data from a life-cycle analysis (LCA) which are specific to the Swiss economy and environment and will not reflect UK circumstances accurately.

The plastic "Linpouch" for drinks packaging has several potentially favourable attributes. It is extremely light - four times lighter than the paper carton, according to Linpac; it has a disposal volume 12-30 times less than the carton; and it can readily be recycled with other low-density polyethylene wastes.

Linpac has put figures on these "environmental dividends" in its promotional material for the Linpouch. It gives the package a score of 17 Environmental Protection Points (EPPs), compared with 30 EPPs for a returnable plastic bottle returned 100 times, 40 EPPs for a returnable glass bottle used 40 times, and 90 EPPs for a paper-board carton.

The figures are based on work by the Swiss Federal Office for the Environment and the Swiss retail chain Migros. For Migros' customers the environmental argument was apparently so compelling that within a few months almost half the retailer's milk sales were in pouches.

The LCA methodology used to compare the various packaging types was based on "environmental scarcity". This weights the releases of various chemicals to different media as calculated in the inventory stage of the LCA by a factor based on the environment's capacity to assimilate each substance without suffering damage - the "critical load" - and the actual level of man-made emissions of each substance.

For example, the "ecofactor" for nitrogen oxides was set at 42.3 ecopoints per gram of NOx on the basis of a critical load of 67,200 tonnes per year and actual emissions of 191,000 tonnes per year in Switzerland.

This method has its drawbacks. The critical load is normally based on limits set in regulations, although these do not necessarily reflect the environment's capacity to assimilate the pollutants concerned. It also fails to take into account local impacts such as whether the discharge is to an unpolluted medium or one already grossly polluted.

But the most important shortcoming is that the "environmental scarcity" approach is related to the environmental characteristics of a particular region - in this case Switzerland. Likewise, the LCA inventory is based on Swiss practice. For example, Switzerland's refuse incineration rate of 75% means that air emissions are the most significant environmental impact. Transport impacts were not included in the analysis, but would also differ between nations.

Linpac does not mention the Swiss origin of the data in its promotional material. Indeed, it appears that the company has not even seen the full Swiss LCA, relying instead on an article in a German journal. Product Manager Trevor Komaromy claims that this was "not a bad guide in terms of ratios", especially because the Swiss data are based on a pouch of 7 grams, compared with the 5-gram Linpouch.

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