TY - JOUR
T1 - Spatial and vertical distribution of polycyclic aromatic hydrocarbons in mangrove sediments
AU - Ke, L.
AU - Yu, K. S.H.
AU - Wong, Y. S.
AU - Tam, N. F.Y.
N1 - Funding Information:
The authors sincerely thank Mr. Benz Chan for his technical assistance in GC analysis and Mr. Ilex Pak for editing the maps. The work described in this paper was substantially supported by a grant from the Research Grant Council, HKSAR (Ref. no. CityU 1110/02M).
PY - 2005/3/20
Y1 - 2005/3/20
N2 - The distribution and historical changes of polycyclic aromatic hydrocarbons (PAHs) contamination in mangrove sediments in Hong Kong SAR were investigated. Surface sediments (2-3 cm) collected from four mangrove swamps exhibited significant spatial variations in concentrations of total PAH (with ΣPAHs ranging from 56 to 3758 ng g-1 dry wt), as well as the composition of 16 USEPA priority PAH compounds. Within a small swamp with an area of 0.68 ha, the total PAH concentrations also differed from sampling site to site, indicating that the PAH contamination is localized and confined to a very small area within the same swamp. Discharges from municipal and industrial wastewater, urban runoff, oil leakage from boats and ships, and accidental oil spill are possible sources of the PAH contamination. The sediment depth profiles reveal that the surface sediment layer (0-5 cm) had lower total PAH concentrations than that in the bottom layer (15-20 cm), and PAH composition also changed with the sediment layers. Based on the estimated annual sediment deposition rate in Hong Kong SAR of around 0.4-0.5 cm, the present findings suggest that the PAH contamination was most serious between 1958 and 1979 but started to decline thereafter. Such decline was probably due to changes in petroleum usage in urban areas and a better control of wastewater discharges from 1980 onwards in this region.
AB - The distribution and historical changes of polycyclic aromatic hydrocarbons (PAHs) contamination in mangrove sediments in Hong Kong SAR were investigated. Surface sediments (2-3 cm) collected from four mangrove swamps exhibited significant spatial variations in concentrations of total PAH (with ΣPAHs ranging from 56 to 3758 ng g-1 dry wt), as well as the composition of 16 USEPA priority PAH compounds. Within a small swamp with an area of 0.68 ha, the total PAH concentrations also differed from sampling site to site, indicating that the PAH contamination is localized and confined to a very small area within the same swamp. Discharges from municipal and industrial wastewater, urban runoff, oil leakage from boats and ships, and accidental oil spill are possible sources of the PAH contamination. The sediment depth profiles reveal that the surface sediment layer (0-5 cm) had lower total PAH concentrations than that in the bottom layer (15-20 cm), and PAH composition also changed with the sediment layers. Based on the estimated annual sediment deposition rate in Hong Kong SAR of around 0.4-0.5 cm, the present findings suggest that the PAH contamination was most serious between 1958 and 1979 but started to decline thereafter. Such decline was probably due to changes in petroleum usage in urban areas and a better control of wastewater discharges from 1980 onwards in this region.
KW - Historical contamination
KW - Mangrove swamp
KW - PAH profile
KW - Variation
UR - http://www.scopus.com/inward/record.url?scp=14844312006&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2004.08.015
DO - 10.1016/j.scitotenv.2004.08.015
M3 - Article
C2 - 15752500
AN - SCOPUS:14844312006
SN - 0048-9697
VL - 340
SP - 177
EP - 187
JO - Science of the Total Environment
JF - Science of the Total Environment
IS - 1-3
ER -