Showing papers by "Mahidol University International College published in 2004"

Ultrastructural alterations in the liver and kidney of white sea bass, Lates calcarifer, in acute and subchronic cadmium exposure

Abstract: Ultrastructural alterations in the liver and kidney of 3-month-old white sea bass, Latescalcarifer, after cadmium exposure were studied by transmission electron microscopy (TEM). One group of fish was exposed to a cadmium concentration of 10 mg/L (acute) for 96 h in a static system, and another group was exposed to cadmium concentrations of 0.8 and 3 mg/L cadmium (subchronic) for 3 months in a recirculation closed system. Ultrastructural alterations observed in the hepatocytes included mitochondrial condensation, swelling, and lysis. The rough endoplasmic reticulum (RER) showed dilation, fragmentation, and vesiculation. After subchronic exposure there were numerous large lipid droplets and abundant stored glycogen. Ultrastructural alterations observed in the proximal tubules of the kidney included nuclear degeneration, condensation, and massive swelling of the mitochondria; RER fragmentation and vesiculation. Disorganized brush borders and increased numbers of large hydropic vacuoles and lysosomes were also observed. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 11–19, 2004.

Phytoextraction and accumulation of lead from contaminated soil by vetiver grass: Laboratory and simulated field study

Abstract: A soil-culture study was conducted to investigate the phytoextraction of lead (Pb) in two species of vetiver grass (Vetiveria zizanioides and V. nemoralis) irrigated with an increasing level of Pb(NO3)2 (5, 7, 9 and 11 g L-1) for 12 weeks. In a laboratory study, the removalof lead from soil was correlated with lead accumulation by roots and shoots of both species of vetiver grass. High concentration of lead (9—11 g L-1) resulted in decrease of growth, total chlorophyllcontent and biomass of V. zizanioides, while V. nemoralis died after one week of application. Toxicity symptoms (e.g., burning leaf margins, shoot die back) occurred in vetiver grass at a high concentration of lead. Based on the data V. zizanioides tolerated and accumulated the greatest amount of lead most effectively. A simulated field experiment was conducted to examine the efficiency of vetiver grass in removing lead from contaminated soil. The vetiver grasses, V. zizanioides and V. nemoralis, were grown in soil contaminated with Pb(NO3)2 (5, 7, 9, and 11 g L-1) for 3 months. The removal of lead from soil was correlated with lead accumulation by roots and shoots of both grass species. The grass roots took up more lead than the shoots. V. zizanioides could uptake more lead from soil than V. nemoralis. The effects of lead on the biomass of V. zizanioides and V. nemoralisshowed that in both species, the biomass was decreased when the lead concentration was increased. In comparison, V. zizanioidesshowed greater biomass than V. nemoralis.

Removal of lead from contaminated soils by Typha angustifolia

Abstract: A greenhouse study was demonstrated for removal of lead (Pb) from contaminated soil by the narrow — leaved cattail, Typha angustifolia. The plants were grown in sandy loam soil containing various concentrations of Pb(NO3)2 (53.3, 106.7, 160, 213.3, and 266.7 mg Pb kg-1 soil). Most lead was accumulated in roots and then transported to leaves. In soil contaminated with 266.7 mg kg-1 of lead, the plants accumulated 7492.6 mg Pb kg-1 dry weight in the roots and 167 mg Pb kg-1 dry weight in the leaves. Yet, no growth retardation from lead was detected. T. angustifolia has high potential as a plant to clean up lead contaminated soil due to its vigorous growth, high biomass productivity, and because it is a perennial in nature. Further work is required to study on the iron plaque formation and its role in metal immobilization.