3. Results
From the calculation methods used we obtain three types of re¬sults: the first and second from the two methods for estimating to¬tal impact (Cases 1 and 2), and the third from the comparison of alternative waste management systems. Impact categories contrib¬uting to savings less than 0.5% of one person's annual average im¬pact are not included in the results. This leaves us with six impact categories, of which human toxicity via water is the most impor¬tant due to replacement of virgin aluminium production.