Temporal variation of mercury and methyl mercury in water and accumulation by phytoplankton in the eutrophic estuary, northern Taiwan.

Three surveys were carried out to study the phytoplankton role in influencing the Hg distribution in a poorly eutrophic estuary by measuring the total Hg (THg) and methylHg (MeHg) concentrations in waters and four-size fractions of phytoplankton. The THg and MeHg concentrations in waters and phytoplankton varied markedly temporal during the three surveys. The total concentrations of THg and MeHg in the four-size fractions of phytoplankton ranged between 0.

Spatial variability of nitrogen cycling in the sediments of the Danshuie River Estuary (Northern Taiwan).

Dissolved N species, TOC and total N (TN) in sediment cores (SC) collected from an eutrophic estuary were analyzed to understand the N geochemical variation in SC of the eutrophic estuary. Extremely higher concentrations of ammonium (6550 μM) and DON (2050 μM) were observed in pore water of the upper estuary and both concentrations generally accounted for 65-99 % and 1-34 % of the dissolved total N pool, respectively, in the three sediment pore waters. The DON and TN concentrations decreased with increasing depth in SC of the upper estuary, opposite the ammonium profile, suggesting that the mineralization of DON and TN provided the ammonium source to the SC.

The geochemical and environmental characteristics of trace metals in surface sediments of the river estuarine mouths around the Taiwan Island and the Taiwan Strait.

The trace metals species in surface sediments of the Taiwanese river estuarine mouths and the Taiwan Strait were examined by sequential extraction method. Based on the metal species present in sediments, trace metals can be divided into three groups: (1) Co, Cr, Fe, Ni and Zn; (2) Cu and Hg; and (3) Mn and Pb. The total concentrations of trace metals in the first two groups are dominated by the residual fraction.

Dissolved and particulate nitrogen species partitioning and distribution in the Danshuei River estuary, northern Taiwan.

Danshuei River Estuary (DRE) total and inorganic nitrogen in the dissolved (TDN, DIN) and particulate (TPN, PIN) phases were analyzed to study their distribution and partitioning. The carbon contents in particles were also analyzed. The upper estuary contained higher ammonium concentration (304-557 μM), leading to TDN completely dominating (>95%) the total N (TDN + TPN) pool within the DRE.

Dissolved and particulate phosphorus species partitioning and distribution in the Danshuei River Estuary, Northern Taiwan.

Different phosphorus fractions, including total dissolved P (TDP), dissolved inorganic P (DIP), total particulate P (TPP), and particulate inorganic P (PIP), were analyzed in the Danshuei River Estuary (DRE), northern Taiwan to study the P partitioning within the estuary. Relatively higher concentrations of TDP (4.3-12.

Mini review of trace metal contamination status in East China Sea sediment.

This study reviewed the published papers and employed the guideline values of USEPA (ERL and ERM) and China (MSQ, Class I, II, III) to assess the contamination status of potential toxic metals in East China Sea sediment (ECS). The percentages of metal concentrations exceeding the ERL value follow the sequences: Ni (96%) > As(71%) > Cr(53%) > Cu (19%) > Zn (2.4%) > Hg (0.

Occurrence and distribution of pharmaceutical compounds in the Danshuei River Estuary and the Northern Taiwan Strait.

Ten pharmaceutically active compounds (PhACs) were determined in northern Taiwan estuarine waters and Taiwan Strait (TS) seawater. The ecological risk of these PhACs was assessed using risk quotient (RQ), which is the ratio of the measured maximum concentration to the predicted no-effect concentration. Six PhACs were detected within the estuarine waters.

Green oysters occurring in an industrial harbor in Central Taiwan.

Green oysters were found within the Mailiao industrial harbor (MIH) located in Central Taiwan. The metal concentrations in seawater (dissolved and particulate phases), sediment and oyster samples collected within the MIH were analyzed to examine the green oysters. The dissolved and particulate metal concentrations ranged within 0.

Arsenic speciation and diffusion flux in Danshuei Estuary sediments, Northern Taiwan.

Sedimentary As, Fe and Mn species in core sediments from the Danshuei Estuary, an anoxic estuary, were studied using a five-sequential extraction method followed by chemical analyses of these elements. The sediment texture, redox potential and dissolved concentrations of these elements in pore water were also determined. Dissolved As diffusion flux was also calculated.

Hg bioaccumulation in marine copepods around hydrothermal vents and the adjacent marine environment in northeastern Taiwan.

The Hg concentration in seawater and copepod samples collected from the area around hydrothermal vents at Kueishan Island and the adjacent marine environment in northeastern Taiwan were analyzed to study Hg bioaccumulation in copepods living in polluted and clean marine environments. The seawater collected from the hydrothermal vent area had an extremely high concentration of dissolved Hg, 50.6-256 ng l(-1).

The occurrence and distribution of pharmaceutical compounds in the effluents of a major sewage treatment plant in Northern Taiwan and the receiving coastal waters.

The pharmaceutical residues in waste water from the largest sewage treatment plant (STP) in Northern Taiwan and in seawater around the effluent discharged area were determined. An environmental risk assessment for the marine environment was conducted based on the environment risk quotient (ERQ). The concentrations of the analyzed compounds in STP influent and effluent were generally higher than those found in coastal seawater.

Mercury contamination and accumulation in sediments of the East China Sea.

Mercury (Hg) concentrations in sediment samples collected from the inner and middle shelves of the East China Sea (ECS) were analyzed to evaluate Hg contamination levels and to calculate Hg sedimentation rates and total accumulation in the ECS. The range of Hg concentrations in surface sediments of the inner shelf was 26.5-47.

Distribution and contamination of trace metals in surface sediments of the East China Sea.

The distributions, contamination status and annual sedimentation flux of trace metals in surface sediments of the East China Sea (ECS) were studied. Higher concentrations of the studied metals were generally found in the inner shelf and the concentrations decreased seaward. The sequences of the enrichment factor (EF) of the studied metals are Cu>Mn>Ni>Zn>Pb>Fe.

Trace metals in seawater and copepods in the ocean outfall area off the northern Taiwan coast.

The distribution, partitioning and concentrations of trace metals (Cd, Cr, Cu, Fe, Mn, Pb and Zn) in seawater, including dissolved and particulate phases, and in copepods in the ocean outfall area off the northern coast of Taiwan were investigated. Normalization of metal concentrations to the background metal concentration to yield relative enrichment factors (EF), which were used to evaluate the contamination of dissolved and particulate trace metals in seawater around the ocean outfall. The EF results indicated that the outfall area was significantly contaminated by dissolved Fe and Zn, and by particulate Fe, Cr, Cu, Pb and Zn.