Ming-Chao Lin

An integrated GIS-based approach in assessing carcinogenic risks via food-chain exposure in arsenic-affected groundwater areas

This study presented an integrated GIS‐based approach for assessing potential carcinogenic risks via food‐chain exposure of ingesting inorganic arsenic (As) in aquacultural tilapia, milkfish, mullet, and clam in the As‐affected groundwater areas. To integrate spatial information, geographic information system (GIS) was adopted to combine polygon‐shaped features of aquacultural species with cell‐shaped features of As contamination in groundwater. Owing to sparse measured data, Monte Carlo simulation and sequential indicator simulation were used to characterize the uncertainty of assessed parameters. Target cancer risks (TRs) of ingesting As contents at fish ponds were spatially mapped to assess potential risks to human health. The analyzed results reveal that clam farmed at the western coastal ponds and milkfish farmed at the southwestern coastal ponds have high risks to human health, whereas tilapia cultivated mainly at the inland ponds only has high risks at the 95th percentile of TR. Mullet in general has low risks to human health. Moreover, to decrease risks, this study suggests reducing the use of As‐affected groundwater at clam and milkfish ponds due to high bioconcentration factor (BCF) of clam and inorganic As accumulation ratio of milkfish. The integrated GIS‐based approach can provide fishery administrators with an effective management strategy at specific fish ponds with high risks to human health.

Drag, morphology and mechanical properties of three species of octocorals

Abstract Drag force, morphology and mechanical properties of three Sarcophyton species, S. buitendijki Verseveldt, S. cinereum Tixier-Durivault and S. crassocaule Moser were studied. Among the three species, S. buitendijki has the highest flexibility and lowest stiffness that enable them to bend into a drag-reducing orientation by collapsing the colony and lying near the substratum at higher velocities. S. cinereum has intermediate flexibility and stiffness; deformation of the colony does not result in the reduction of drag forces, it resists drag forces by stiffness. Colonies of S. crassocaule have the highest stiffness which allows them to retain streamlining. They reduce drag forces by staying in the lower-velocity boundary layer. This study shows that the three sympatric Sarcophyton species possess different morphological and mechanical properties and they coexist in the same environment by adopting different strategies to reduce drag forces.

Shrimp shell as a potential sorbent for removal of arsenic from aqueous solution.

This study examined the ability of shrimp shell to remove arsenic (As) from aqueous solutions. The shells of two species of shrimp, black tiger shrimp Penaeus monodon and white shrimp Litopenaeus vannamei, were chosen to be the sorbents. Laboratory exposure experiments estimated uptake and depuration rate constants (i.e., k1 and k2) as well as the bioconcentration factors (BCF) of the shells of the two shrimps. A first-order one-compartment model was presented to describe the uptake kinetics of As in shrimp shell. The resulting k1, k2, and BCF values of black tiger shrimp were 0.034–1.722xa0ml/g/day, 0.007–0.345xa0g/g/day, and 5.08xa0±xa01.56xa0ml/g, while those for white shrimp were 0.053–0.523xa0ml/g/day, 0.011–0.237xa0g/g/day, and 3.95xa0±xa01.88xa0ml/g, respectively. The sorption capacities of black tiger shrimp shell and white shrimp shell were 1.08xa0×xa010−4–6.66xa0×xa010−3 and 1.04xa0×xa010−4–3.26xa0×xa010−3xa0mmol/g, respectively. The sorption capacity of shrimp shell increased with the initial As concentration in water. Shrimp shell, as a waste material, could be potentially used for the removal of As from an aqueous medium. Although the As-removal capacity of shrimp shell was lower than those of natural and chemical sorbents, using shrimp shells as sorbents is less expensive and could increase the additional value of shrimp products.

Shell of abalone Haliotis diversicolor supertexta can eliminate waterborne zinc biokinetically.

Dietary and nondietary accumulation of waterborne zinc (Zn) by shell of abalone Haliotis diversicolor supertexta was studied to determine if abalone shell can accumulate and eliminate Zn biokinetically. Shell of H. diversicolor supertexta rapidly accumulated Zn at microgram per gram concentrations during a 7-d uptake period for dietary and nondietary exposure to 1 microgml(-1) Zn seawater. Depuration half-lives were 7.22 and 15.40 d for dietary and nondietary exposure, respectively. The uptake rate constants were 5.12 and 4.84 ml g(-1)d(-1), respectively, for dietary and nondietary exposure. The depuration rate constants were 0.048 and 0.10 d(-1), respectively for dietary and nondietary exposure. Results from this study showed that the shell of H. diversicolor supertexta accumulated Zn and that it reflected the composition of the seawater in which the abalone lived. This suggested that the shell of H. diversicolor supertexta can be used as a bioindicator or can act as a receptor to biokinetically eliminate heavy metals from aquatic food webs.