  Globally, 7-10 billion tonnes of waste are produced annually, including
300-500 million tonnes of hazardous wastes (HW)--explosive, flammable, toxic,
corrosive, and infective ones. About 10 % of these HW are traded through a
world-wide waste web (W4). The volume of HW traded through the W4 in the last
30 years has grown by 500 % and will continue to grow, creating serious legal,
economic, environmental and health problems at global scale. Here we
investigate the tip of the iceberg of the W4 by studying networks of 108
categories of wastes traded among 163 countries in the period 2003-2009.
Although, most of the HW were traded between developed nations, a
disproportionate asymmetry existed in the flow of waste from developed to
developing countries. Using a dynamical model we simulate how waste congestion
propagates through the W4. We identify 32 countries with poor environmental
performance which are at high risk of waste congestion. Therefore, they are a
threat of improper handling and disposal of HW. We found contamination by heavy
metals (HM), by volatile organic compounds (VOC) and/or by persistent organic
pollutants (POP), which were used as chemical fingerprints (CF) of the improper
handling of HW in 94 % of these countries.
