INTRODUCTION
In order to reduce current environmental problems, the
industrialized world has made plans aiming to increase
the recycling of domestic waste. This goal has being accomplished
in Portugal with the opening of several wastesorting
units since 1995.
Domestic waste includes different types of materials,
namely non-biodegradable waste such as plastic materials,
metals, glass, paper and cardboard; and non-separated
general waste. Most of the non-biodegradable waste represents
an important recyclable fraction composed normally
of paper, cardboard, plastic materials, wood, glass,
and metals. These kinds of waste are sorted at refuse
transfer stations to produce raw materials for recycling,
and this process usually requires direct waste contact on
the part of workers [1].
Although a high amount of research has been focused on
the health of the population living near waste disposal