| dc.description.abstract |
This first study investigated the presence of dioxins and furans in river sediments around a
craft village in Vietnam, focusing on Secondary Steel Recycling. Sediment samples were collected
from various locations along the riverbed near the Da Hoi Secondary Steel Recycling village in Bac
Ninh province. The analysis was conducted using a HRGC/HRMS-DFS device, detecting a total
of 17 dioxin/furan isomers in all samples, with an average total concentration of 288.86 ng/kg d.w.
The concentrations of dioxin/furan congeners showed minimal variation among sediment samples,
ranging from 253.9 to 344.2 ng/kg d.w. The predominant compounds in the dioxin group were
OCDD, while in the furan group, they were 1,2,3,4,6,7,8-HpCDF and OCDF. The chlorine content
in the molecule appeared to be closely related to the concentration of dioxins and their percentage
distribution. However, the levels of furan isomers did not vary significantly. The distribution of
these compounds was not dependent on the flow direction, as they were mainly found in solid waste
and are not water-soluble. Although the hepta and octa congeners had high concentrations, when
converted to TEQ values, the tetra and penta groups (for dioxins) and the penta and hexa groups (for
furans) contributed more to toxicity. Furthermore, the source of dioxins in sediments at Da Hoi does
not only originate from steel recycling production activities but also from other combustion sites. The
average total toxicity was 10.92 ng TEQ/kg d.w, ranging from 4.99 to 17.88 ng TEQ/kg d.w, which
did not exceed the threshold specified in QCVN 43:2017/BTNMT, the National Technical Regulation
on Sediment Quality. Nonetheless, these levels are still concerning. The presence of these toxic
substances not only impacts aquatic organisms in the sampled water environment but also poses
potential health risks to residents living nearby. |
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