Jiwarungrueangkul et al. 2025

Surface sediments were collected from seventeen stations along three transects in the inner Gulf of Thailand (GoT) in the rainy and dry seasons. This study offers the first comprehensive assessment of geochemical fractions, spatiotemporal distributions, and ecological risks of heavy metals in the inner GoT sediments. The average total concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn were 9.43 +/- 4.46, 0.20 +/- 0.09, 68.93 +/- 23.55, 22.86 +/- 12.90, 27.50 +/- 7.81, 24.17 +/- 12.26, and 66.55 +/- 35.01 mu g/g dry weight, respectively. Their concentrations were generally high in river mouth, indicating that rivers serve as major inputs. Except for Pb, all heavy metals predominantly existed in the residual fraction, implying that most of the heavy metals accumulated in the inner GoT sediments are lithogenic origins and have low bioavailability metals. Risk assessments using multiple sediment quality approaches (I-geo, EF, and RAC) can prioritize the metals of concern as follows: Cd >> Zn > Cr > Cu > As > Ni > Pb. Meanwhile, mCd, M-ERM-Q, [Sigma SEMs]-[AVS], and [Sigma Fs]-[AVS] approaches indicated an overall medium-low ecological risk, but the river mouth serves as a key surveillance site. These findings can provide information necessary to plan environmental management strategies for metal contamination in coastal sediments.

Reference: Jiwarungrueangkul, T., Khokiattiwong, S., Tipmanee, D., Sangmanee, C., Charoenpong, C., Khammanee, N., & Sompongchaiyakul, P. (2025). Geochemical speciation and comparative risk assessment of heavy metals in the marine sediments under anthropogenic pressure: A case study from the inner Gulf of Thailand. Regional Studies in Marine Science, 104625.