Kuo-Ming Huang

Influence of the Yangtze River and grain size on the spatial variations of heavy metals and organic carbon in the East China Sea continental shelf sediments

Abstract Bulk heavy metal (Fe, Mn, Zn, Cu, Pb, Cd), Al, organic carbon and carbonate concentrations, grain sizes, and δC13 of the organic carbon distributions were studied in sediments collected throughout the East China Sea continental shelf and the Yangtze River Delta. The results demonstrated that terrigenous sediments from the Yangtze River is a dominating factor controlling the spatial variations of heavy metals and organic carbon concentrations on the East China Sea continental shelf. In addition, grain size and recent anthropogenic influences are also major factors modifying the spatial and vertical variations of heavy metals. Large spatial variations with a band type distribution of heavy metals, grain size, organic carbon and carbonate were observed. Higher concentrations of heavy metal and light δC13 of the organic carbon were found primarily in the Deltaic and inner shelf sediments. The band type distribution generally followed the coastline with little variations in the north–south direction. Away from the Delta and inner shelf (west–east direction), most heavy metal concentrations decreased rapidly with the exception of Cd where high concentrations of Cd were also found in the carbonate-rich shelf break sediments. Coarse-grained relict sediments and biogenic carbonate are two primary diluting agents for the fine-grained aluminosilicate sediments from the Yangtze River with high concentrations of heavy metals. Unusually high concentrations of Cu, Pb, and Cd showed both spatially and vertically that more pollution prevention measures are needed in the Yangtze River drainage basin in order to prevent further heavy metal pollution of the East China Sea inner continental shelf.

Consequences and implication of heavy metal spatial variations in sediments of the Keelung River drainage basin, Taiwan

A great deal of effort was enforced to reduce the pollution of the Keelung River in the past 20 years. A set of sediments covering most of the Keelung River drainage basin was analyzed for bulk sediment heavy metal concentrations, grain size content and Pb-210 dating in order to understand the spatial variations of sediment heavy metal contents as well as to evaluate the effectiveness of pollution control. The results showed that anthropogenic pollution and grain size are two of the most important factors in controlling spatial variations of metals in the Keelung River sediments. In addition, little reduction of sediment heavy metal concentrations was observed in the Keelung River drainage basin. Large spatial variations of metals and grain size were observed. High concentrations of zinc, copper, lead and cadmium were found in sediments near the main outlets of the adjacent Da-Wu-Lun Industrial Park and municipal waste drainage systems. Anthropogenic sources of heavy metal have altered the natural sediment heavy metal distributions. Positive linear relationships between aluminum, iron and fine-grained sediments showed that spatial grain size variations controlled the natural aluminum and iron concentrations in sediments. Zinc, copper, lead and cadmium contents were much higher than those measured 15 years ago. The unusually high concentrations of heavy metals, high enrichment factors and their rapid increases with time in Pb-210 dated core showed that the efforts in heavy metal reduction were futile. A proper regulation to prevent further heavy metals from entering into the river is urgently needed.

Unusual Manifestations of Vertebral Osteomyelitis: Intraosseous Lesions Mimicking Metastases

BACKGROUND AND PURPOSE: Vertebral osteomyelitis can have different imaging manifestations. The purpose of this study was to demonstrate the unusual MR imaging patterns of vertebral osteomyelitis with intraosseous lesions mimicking metastases. MATERIALS AND METHODS: From September 2000 to August 2007, 7 patients were selected from our data base of 214 patients with confirmed vertebral osteomyelitis and MR images. All of those having misinterpreted MR imaging reports and unusual imaging patterns were analyzed. The presence of a peripheral curvilinear area of low signal intensity in an osseous lesion (the rim sign) and a peripheral rim of high signal intensity on T2-weighted images around an osseous lesion (the halo sign) was evaluated. Follow-up MR imaging studies were performed in all patients. RESULTS: The patients were 5 men and 2 women, with an age range of 42–80 years. MR imaging findings of those with vertebral osteomyelitis showed a solitary lesion in 2 and multiple lesions in 5 patients. The intraosseous lesions revealed low signal intensity on T1-weighted images, mixed or high signal intensity on T2-weighted images, high signal intensity on short τ inversion recovery images, and global or marginal enhancement. The rim sign was found in 6 (86%) patients; halo sign, in 7 (100%); preserved intervertebral disks, in 7 (100%); and limited paraspinal or epidural inflammation, in 6 (86%). Images of all patients demonstrated healing or almost healed changes on the follow-up MR imaging studies. CONCLUSION: Vertebral osteomyelitis can have MR imaging patterns mimicking osseous metastases. Recognition of these unusual imaging manifestations, together with clinical and histopathologic analysis, may aid in reaching the correct diagnosis.

PAST AND PRESENT RECORDS OF GAS HYDRATE GEOCHEMICAL SIGNATURES IN A TERRIGENOUS MATERIALS DOMINATED ACTIVE MARGIN, SOUTHWEST OF TAIWAN

Temporal variations in gas hydrate related geochemical signatures under different deposition conditions are the primary purposes of this study. Accreted wedge located offshore Southwestern Taiwan receives high terrigenous river materials, 100 MT/yr, at present time. It is not clear how seep environment varied during the past glacial. A 25 meters long piston core was taken offshore Southwestern Taiwan on r/v Marion DuFresne. Short piston cores and box cores were also taken on r/v OR-1. Samples were analyzed for pore water dissolved sulfide, sulfate, methane, chloride, del O18, calcium, magnesium, alkalinity, pH, and sediment AVS, pyrite, inorganic carbon, del O18, C13. Changes in deposition environment play a major role in the study area. Three stages of geochemical processes are identified in the 25 meters long core, interchange between reduce and oxic depositional environments, with reducing condition in the top 10 m, oxic in between 10-20 meter and reducing below the 20 meter. High concentrations of dissolved sulfide, rapid sulfate depletion, increase of methane, decrease of calcium were found in pore water in the top 10 m of sediments together with high concentrations of pyrite, relatively higher proportion of coarsegrained sediment. Concentrations of pyrite were very low in sediments between 15 to 20 meters but increased rapidly from 20 to 25 meters with a maximum concentration at 400 umol/g. Chloride concentrations also increased to a maximum concentration of 630 mM at 20 m. The rapid increase of chloride indicated gas hydrate formation at this depth. Authigenic carbonate