Electronic waste (e-waste) is a source of harmful dioxins in Africa,
according to research by Japanese scientists. They published their results in
the journal Environmental Science & Technology. E-waste refers to
end-of-life products such as communication devices, consumer electronics and
home appliances. Due to the presence of toxic substances such as heavy metals
and many various plastic additives in e-waste, the discarded materials are
considered hazardous and must be handled properly. Yet, a large volume of
e-waste has been recycled inappropriately and treated informally in Asian and
African developing countries. Primitive methods such as circuit board heating
and open burning of wires have thus led to serious environmental pollution,
caused by the emission of not only contaminants contained in e-waste, but also
unintentionally-formed secondary toxic chemicals. In this study, researchers
led by Professor Tatsuya Kunisue of Ehime University, Japan, found dioxins—a
toxic substance generated during informal processing of e-waste—in soils from
the Agbogbloshie e-waste site in Ghana. The researchers used analytical methods
based on two-dimensional gas chromatography and time-of-flight mass spectrometry
to profile halogenated contaminants in the soils collected near e-waste burning
and dismantling areas. They identified polybrominated and mixed halogenated
dibenzofurans (PBDFs and PXDFs) as the major dioxin. PBDFs were generated from
a group of flame retardants commonly found in e-waste plastics. On the other
hand, PXDFs were mainly produced from PBDFs through successive
bromine-to-chlorine exchange, said the researchers. High concentrations of
PXDFs in e-waste burning areas indicate that these ‘hidden’ dioxins may
contribute substantially to the total toxicity of the e-waste-derived dioxin
mixture, and need to be included in future environmental and human exposure
risk assessment.
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