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.

Latsamy Soulivongsa,Bundit Tengjaroenkul,Lamyai Neeratanaphan,Isara Patawang

doi:10.3390/ijerph18115854

Abstract

This study aimed to determine toxic element concentrations in aquatic environments, including water and sediment, and in the Hampala macrolepidota fish, and to evaluate chromosome abnormalities, serum liver enzyme changes and liver histopathological alterations in H. macrolepidota from the Nam Kok River near the Sepon gold-copper mine, Lao People’s Democratic Republic, as compared with a control area without mining activity. The results revealed significant differences (p < 0.05) in As, Ba, Cu, Fe, Mn, Ni, Se and Zn in water, in all of the studied potentially toxic elements in sediment, and in As, Ba, Cd, Cr, Cu, Mn, Ni, Se, and Zn in the fish between the study and control areas. A chromosome assessment demonstrated 6 types of chromosome abnormalities, among which centric gap had the highest total number of chromosome abnormalities. Percentage of chromosome abnormalities, percentage of cells with chromosome abnormalities and serum liver enzymes in H. macrolepidota were significantly different (p < 0.05) between the two studied areas and were higher in the contaminated fish than in the control fish. The observation of liver histopathological changes revealed cellular degeneration, such as nuclear damage, abnormal cytoplasmic mitochondria and the disintegration of rough endoplasmic reticulum. The results indicate that the contamination of potentially toxic elements in the Nam Kok River near the Sepon gold-copper mine area negatively affected chromosomes, serum liver enzymes and liver cell structures in H. macrolepidota.

Highlights

Introduction iationsThe Lao People’s Democratic Republic includes mountainous regions with natural scenery as well as various valuable mineral resources in several regions of the country
The results revealed that the 6 types of chromosome abnormalities in H. macrolepidota from the gold mining area were centric gaps, fragmentations, single chromatid gaps, deletions, single chromatid breaks and centric fragmentations, with a total number of chromosomal abnormalities being 127, 3, 3, 22, 1, and 15, respectively
Most of the measurements of water quality parameters were within the standards for non-contaminated surface water [38], especially dissolved oxygen (DO), temperature, Most of the measurements water quality parameters were within (EC), the standards for that the the potential of of hydrogen and electrical conductivity and indicated non-contaminated surface water

Summary

Introduction

The Lao People’s Democratic Republic includes mountainous regions with natural scenery as well as various valuable mineral resources in several regions of the country. The Lao government has promoted ore resources as a mechanism for increasing the gross domestic product of the country [1,2]. In 2018, the major valuable ore commodities from the Lao People’s Democratic Republic were gold and copper, with estimated export values of 200 and 502 million USD, respectively [3,4]. By 2020, the value of the total metal exports is predicted to account for 10% of Laos’s gross domestic product. In addition to the mining industry, aquaculture and fishery are major essential economic sectors in the Lao People’s Democratic Republic, accounting for more than half of animal The Sepon gold-copper mine in the Savannakhet Province is the second largest gold-copper mine, which contributes to 90% of the country’s total economic value from the mining sector [1,3].

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