To investigate the effect of dissolved oxygen deficiency on the level of 210Pb
in mussel's tissues, Perna viridis which has been reported to be
highly tolerant to hypoxia.
Methodology: Mussels (Perna viridis), seawater and
sediment samples were collected from nine stations along the Johor Straits
during North-east monsoon (November 2017), inter-monsoon (March 2018), and
South-west monsoon (August 2018). The 210Pb contents were extracted and
estimated by Gross Alpha-beta Counter.
The lowest dissolved oxygen was recorded at Station 4 which decreased from
2.14 mg l-1 to 2.10 mg l-1 and subsequently to 1.63 mg
l-1 during first to third samplings. In sediment, 210Pb
activities increased with the increase in organic matter. Meanwhile, in
mussels, the 210Pb activities showed almost similar trend with
sediment where 210Pb activities were much higher adjacent to the causeway
structure, especially at the East part of Johor Strait. The level of 210Pb
in mussel's tissue and sediment also increased with decreasing level of
Interpretation: A causeway structure disrupted the water
quality of Johor Straits and caused almost hypoxic conditions nearby. The
coverage of oxygen depletion expanded during inter-monsoon. An inverse
relationship between 210Pb activities and dissolved oxygen prove
that deficiency of dissolved oxygen potentially influenced the bioaccumulation
of 210Pb in mussels to correspond to the build-up of concentration
factor in their tissues which exceeded the recommended value.
Dissolved oxygen, Hypoxic, Organic matter, 210Pb, Perna viridis