Effects of Contamination by Heavy Metals and Metalloids on Chromosomes, Serum Biochemistry and Histopathology of the Bonylip Barb Fish Near Sepon Gold-Copper Mine, Lao PDR

Abstract

The objectives of the present study were to determine the concentrations of heavy metals and metalloids in water, sediment and Osteochilus vittatus fish, and to assess chromosome aberrations, serum biochemical changes and histopathological alterations in O. vittatus from the Nam Kok river near the Sepon gold-copper mine, Lao People’s Democratic Republic compared with the reference area. The results showed that Fe, Mn and Ni in water, As and Cd in sediment as well as As, Cd, Cr, Mn and Ni in O. vittatus muscle samples near the gold-copper mine exceeded standard values. Furthermore, the chromosome assessment in O. vittatus revealed seven types of chromosome aberrations, and the highest total number of chromosome aberrations was a centromere gap. The total number of chromosome aberrations, cell number with chromosome aberrations and percentage of chromosome aberrations in O. vittatus as well as serum liver enzymes between the studied areas were significantly different (p < 0.05). The liver histopathological alterations of the fish near the gold-copper mine revealed atypical cellular structures as nuclear membrane degeneration, rough endoplasmic reticulum disintegration and abnormal cytoplasmic mitochondria. The results of this study suggested that heavy metal and metalloid contaminations from the Sepon gold-copper mine area negatively affect O. vittatus fish in terms of chromosomal defects, serum biochemical changes and liver histopathological appearances.

Cytogenetic, Serum Liver Enzymes and Liver Cell Pathology of the Hampala Barb Fish (Hampala macrolepidota) Affected by Toxic Elements in the Contaminated Nam Kok River near the Sepon Gold-Copper Mine, Lao PDR

“…Since the Nam kok River (as the study area located near the gold-copper mine) demonstrated higher levels of, and significantly different (p < 0.05), potentially toxic elements than the Nam Souang River (as a control area without mining activities), the abnormal liver cell structures in H. macrolepidota from the study clearly revealed pathological lesions, including nuclear membrane degeneration, rough endoplasmic reticulum disintegration and abnormal cytoplasmic mitochondria. These changes imply that the potentially toxic element concentrations in H. macrolepidota near the Sepon gold-copper mine could induce liver cell structural changes, as in the bonylip barb fish (O. vittatus) at the same study site [15]. The results were in accordance with several previous studies.…”

“…From previous studies on the Nam Kok River, potentially toxic element accumulations were found to differ among fish species. Soulivongsa et al [15] reported that bony lip barb fish (Osteochilus vittatus) contained As, Cr, Fe, Mn and Ni at greater concentrations than hampala barb fish in this study, with values of 3.48 > 0.30, 4.72 > 3.58, 56.10 > 44.74, 14.76 > 4.19 and 1.76 > 1.70 mg/kg, respectively. These differences suggested that bony lip barb fish, an herbivorous fish, may consume an abundance of contaminated aquatic plants in the river in greater amounts.…”

“…The statistical results revealed that the number of cells with chromosome abnormalities, the total number of chromosome abnormalities and the percentages of chromosome abnormalities were significantly different (p < 0.05) between the H. macrolepidota fish samples from the Nam Kok River near the gold-copper mine and those from the Nam Souang River. Furthermore, compared with bonylip barb fish (Osteochilus vittatus) at the same study site [15], H. macrolepidota fish demonstrated fewer chromosomal effects in terms of the number of cells with chromosome abnormalities, the total number of chromosome abnormalities, and the percentages of chromosome abnormalities. These results could suggest that differences in metal toxicity consequences are species dependent.…”

“…Furthermore, potentially toxic elements can negatively affect fish health in terms of protein, carbohydrate and lipid profiles [66]. Furthermore, compared with bonylip barb fish (O. vittatus) at the same study site [15], H. macrolepidota fish demonstrated greater levels of both liver enzymes, particularly AST, which is directly related to the metal concentrations in the liver of H. macrolepidota fish.…”

“…As a result, the rapid growth of gold-copper mining in the Lao People's Democratic Republic has raised intense concerns involving potentially toxic element emissions into aquatic ecosystems; however, data involving types and concentrations of potentially toxic elements in the environment and the health effects of these elements on H. macrolepidota are limited. Only Soulivongsa et al [15] has reported on five toxic elements in the Nam Kok River and aquatic organisms. Fe, Mn and Ni in the river water as well as As and Cd in the sediment and As and Cd in Osterochilus vittatus fish samples in the river exceeded standard values.…”