IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Research article
erdSome Physico-Chemical Characteristics of Surface Water inMining Areas in the Lao PDRSANTI KONGMANY*
Center of Excellence in Environment, Research and Academic Service Office,National University of Laos, Vientiane Capital, Lao PDR
Email: s.kongmany@nuol.edu.la

VANSENG CHOUNLAMANY
Faculty of Natural Sciences, National University of Laos, Vientiane Capital, Lao PDR

PHETYASONE XAYPANYA
Faculty of Water Resources, National University of Laos, Vientiane Capital, Lao PDR

OULAY PHOUPASONG
Faculty of Environmental Sciences, National University of Laos, Vientiane Capital, Lao PDR

BOUNTHOB PRAXAYSOMBATH
Faculty of Natural Sciences, National University of Laos, Vientiane Capital, Lao PDR

SINDAVANH PHENGTHAVANH
Information Compilation Division, Department of Mining Management,
Ministry of Energy and Mines, Vientiane Capital, Lao PDR
Received 22 February 2022

Accepted 25 April 2022(*Corresponding Author)

Abstract Lao People’s Democratic Republic (the Lao PDR), is naturally enriched withmineral resources having been the important potential in the country socio-economicdevelopment. Mining activities for utilizing such resource is expected to bring not onlybenefit but also environmental problems such as deforestation due to land opening, surface
water quality decline. The objective of this study was to initially investigate the surface
water quality of the two main rivers (Namkok and NamMo) near two mining areas (Seponand PhuBia) in Savannakhet and Xaysomboun provinces, respectively. Water samples from5 sampling sites on each river were analyzed for physical (pH, EC, temperature, turbidity,TDS,) and chemical (alkalinity, DO, COD, inorganic cations and anions, and some heavymetals) characteristics in two sampling times (May and July) in 2021. The finding results
unveiled that the water of the two rivers had temperature of 23-32oC, DO 8-16 mg/L andCOD 1.8-64 mg/L. The water pH, EC, and alkalinity were found at values of 7-8, 83-576µS/cm, and 48-174 mg-CaCO3/L ranges, respectively. In contrast, the amount of TDS in theboth rivers were 53-369 mg/L. The detected dominant cations were Na+, Ca2+ and Mg2+ andtheir concentration was in a concentration range of 0.5-34 mg/L, while main anions were F–, Cl– and SO42- (3-9 mg/L). The particulate matter content in the water in the form of TSS(67-372 mg/L) were observed. The presence of both TDS and TSS might lead to the water
turbidity of as low as 5 NTU or as high as 200 NTU. The investigated heavy metal
concentration was typically low. Based on the findings, the water quality of the two rivers
at the time of investigation was not beyond the Lao national environmental quality criteria.
Keywords physico-chemical characteristics, surface water, mining areas, the Lao PDR

INTRODUCTION
Lao People’s Democratic Republic (Lao PDR or Laos), a country in Indochina peninsula, has an
outstanding abundance of natural resources such as densely forest for reserving the water resourcesⒸ ISERD136

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

and its quality, nutrient-rich abundance for agriculture, streams for agricultural irrigation, humanbeing livelihood and water resources for hydropower development, precious minerals, charm andbeautiful tourist sites (Kiprop, 2019). If well managed and used, the natural resources wealthcontribute to the national development and bring benefit to Lao people (Vostroknutova, 2010).
Depositing in many parts of Laos, it has identified that more than 570 mining areas where gold,copper, zinc and lead covered around 47%, which are the socio-economic development potentialsof Laos (Kyophilvong, 2009). Two main mining companies in Laos are Lanxang Mineral Company
which have been operating at Vilabuly district of Savannakhet province since 1993, and PhuBia
Mining Company Limited which have been operating at Anuvong district of Xaysomboun province
since 1994 (Shibata, 2008).
The environmental impacts from mining is diverse, and various tools are needed formonitoring and assessing the impacts (Islam et al., 2020). Physical, biological and chemical
properties are the main components of water quality for assessing the mining caused impacts to thewater sources environment (Amin et al., 2016; Hirwa et al., 2019). The water quality assessment
could provide important information for protecting environment and people living downstream ofthe mining areas (Gerhardt et al., 2004). However, the mostly concerned river water pollution
caused by mining is the presence of heavy metals of which their concentration and distribution in
the surface water are dominated by the geochemical situation and the pollution source, but
seriously affected by mining leachate and chemical wastewater discharge (Liang et al., 2011).
Therefore, the inspection of mining companies which must follow the environmental standard
criteria and the participation of the publics in the water quality monitoring (WQM) might havechallenges beyond the environmental responsibility of the authorities: (1) scientific soundness, (2)political relevance and (3) harmonization in WQM implementation (Mercado-Garcia et al., 2019).
OBJECTIVE
The objective of this study was to investigate the physico-chemical characteristics of the mainrivers – NamKok and NamMo rivers near the two gold-copper mining areas in Vilabuly andAnuvong districts of Savannakhet and Xaysomboun provinces, respectively.
METHODOLOGY
Sampling Sites and Times
The physico-chemical characteristics of NamKok and NamMo were investigated in two samplingtimes – one in May and another in July as a representative of dry and rainy season in 2021. The
typical maps of the two mining areas where 5 selected sampling sites were marked are shown inFig. 1. The selected sampling sites are the same places where the water quality was also monitoredby the companies’ environmental monitoring units.
Sampling and Analytical Method
The water samples collected by grabbing method were either preserved or non-reserved and stored
in plastic sample bottles according to the parameters - alkalinity, hardness, chemical oxygen
demand (COD), inorganic cations and anions, and heavy metals for being analyzed in a laboratory.
During transportation to the laboratory, the all sample in the bottles were kept in an ice box withcooling packs. The electrical conductivity (EC), pH, dissolved oxygen (DO), temperature andturbidity of water samples was measured at the sampling sites using portable multi-parameter water
quality meter and turbidity meter. Total dissolved solids (TDS) was estimated from EC, while totalsuspended solid (TSS) was determined by Standard Methods 2540 D (dried at 103-105°C),
alkalinity, hardness by titrimetric method, COD by potassium dichromate method, inorganic
cations and anions by ion chromatographic method, heavy metals (Cu, Pb, Cr, As, Hg, Zn, Cd, Ni,Fe) by atomic absorption spectrometric method (APHA et al., 2017).
Ⓒ ISERD137

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Fig. 1 A typical topographic maps of 5 sampling sites in NamMo (NMo1-5) andNamKok (NKok1-5) in PhuBia and Sepon Mining Areas
RESULTS AND DISCUSSION
Temperature, pH, DO and Alkalinity
The comparison of temperature, pH, DO and Alkalinity for the two rivers (NamMo and NamKok)
are shown in Fig. 2. The temperature and pH characteristics of them were similar. In contrast,
NamKok’s DO and alkalinity was somehow higher than those of NamMo. The difference in theriver’s alkalinity in May and July would be due to their seasonal hydrological and geographicalcharacteristics. High alkalinity of these rivers would be good for high buffering capacity of thewater against change in pH (Weiner and Matthews, 2003), and this would be correlated to theobserved pH.

Fig. 2 Temperature, pH, DO and Alkalinity of NamMo (NMo1-5) andNamKok (NKok1-5) in May and July 2021
TDS, TSS, EC, Turbidity and CODⒸ ISERD

138

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

The analytical results of the two rivers in terms of TDS, TSS, EC, turbidity and COD are shown inFig. 3. NamKok river showed its TDS and TSS characteristics higher than that of NamMo in May,but not much different in July, and this would lead to their similar properties on EC. For COD, bothrivers showed high values in opposite month, the reason is still unclear whether by the effect ofwater nature dilution or anthropogenic mining activities (Xu et al., 2020).

Fig. 3 TDS, TSS, EC, Turbidity and COD of NamMo (NMo1-5) andNamKok (NKok1-5) in May and July 2021

Fig. 4 Characteristics of Some heavy metals in NamMo (NMo1-5) andNamKok (NKok1-5) in May and July 2021

Ⓒ ISERD

139

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Characteristics of Some Heavy Metals in NamMo and NamKok
The contamination of heavy metals in water resources nearby the mining operation activities is themost concerned as most of heavy metals are toxic even at very low concentration (Fashola et al.,2016; Liang et al., 2011; Mahato et al., 2017). In this study, the presence of less toxic metals (Fe,Cu, Zn) and much toxic metals (As, Cr, Cd, Ni, Pb, Hg) in NamMo and NamKok rivers wereinvestigated and the results are shown in Fig. 4.
The concentrations of heavy metals in NamKok river were mainly higher than those in
NamMo, except Zn and Ni. The Zn concentration in NamMo river was much higher than that in
NamKok and it is expected that Zn metal might be abundant in nature nearby the NamMo area.
Concerning As, its concentration in NamMo river was found similar in all 5 sampling sites
indicating that such presentation would occur naturally (Wurl et al., 2018).
In contrast, the presence of As in NamKok river in July in downstream was somehow higher
than those in upstream, indicating that leaching As from upstream area due to runoff would beexpected as the cause (Dai et al., 2013). Similarly, the concentration of Hg in water sampled at thedown-stream in both rivers was higher than those at upstream. The presence of Hg in the surface
water could occur through soil erosion, surface runoff, and land use in the mining areas (Dai et al.,2013). The presence of Cr in both NamMo and NamKok rivers is in similar characteristics, while
the highest concentration of Cr peaked at the middle stream. Furthermore, the presence of Cr insuch concentration in both rivers would be due to its natural occurrence (Chrysochoou et al., 2016;
Ferronato and Torretta, 2019; Mani Tripathi and Chaurasia, 2020). The presence of Ni in bothrivers was very low indicated by its concentration below the detection limit.
CONCLUSION
This study unveiled, even not completely, that the water quality of the two rivers - NamMo andNamKok in the mining operation areas at the time of our investigation is still not in serious
situation according to their physico-chemical characteristics which were not beyond the limited
value in comparison to the Lao national environmental standard (2017) on surface water quality.
The water quality of the two rivers would be affected by the seasonal (May versus July) andgeographical (upstream versus downstream) difference. The results from this study could be used
as a fundamental scientific data for further study. However, it is recommended that more sampling
frequency and sites should be further taken into account for future investigation so that the water
characteristics would be more realistic.
ACKNOWLEDGEMENTS
The authors would like acknowledge the Second Strengthening Higher Education Project (SSHEP),
Department of Higher Education, Ministry of Education and Sports of Lao PDR for financial
support. Furthermore, Authors would like to thank Lanxang Mineral Mining Limited and PhuBia
mining companies for facilitating our team in site visiting and sample collection.
REFERENCES
Amin, J.K.M., Shekha, Y.A. and Amin, J.K.M. 2016. Environmental impacts of sand and gravel mining onwater quality and biodiversity in Kalak Sub-District. ZANCO, Journal of Pure and Applied Sciences, 28(5), Retrieved from DOI https://doi.org/10.21271/zjpas.28.5.18
APHA, AWWA and WEF. 2017. Standard methods for the examination of water and wastewater. In
Standard Methods, Retrieved from DOI https://doi.org/10.1016/0043-1354(82)90249-4
Chrysochoou, M., Theologou, E., Bompoti, N., Dermatas, D. and Panagiotakis, I. 2016. Occurrence, origin
and transformation processes of geogenic chromium in soils and sediments. Current Pollution Reports, 2,224-235, Retrieved from DOI https://doi.org/10.1007/s40726-016-0044-2Ⓒ ISERD140IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Dai, Z., Feng, X., Zhang, C., Shang, L. and Qiu, G. 2013. Assessment of mercury erosion by surface water inWanshan mercury mining area. Environmental Research, 125, 2-11, Retrieved from DOI https://doi.org/10.1016/j.envres.2013.03.014
Fashola, O.M., Ngole-Jeme, M.V. and Babalola, O.O. 2016. Heavy metal pollution from gold mines:
Environmental effects and bacterial strategies for resistance. International Journal of Environmental
Research and Public Health, 13 (11), 1047, Retrieved from DOI https://doi.org/10.3390/ijerph13111047
Ferronato, N. and Torretta, V. 2019. Waste mismanagement in developing countries: A review of global
issues. International Journal of Environmental Research and Public Health, 16 (6), 1060, Retrieved fromDOI https://doi.org/10.3390/ijerph16061060
Gerhardt, A., Bisthoven, J.L. de and Soares, A.M.V.M. 2004. Macroinvertebrate response to acid minedrainage: Community metrics and on-line behavioural toxicity bioassay. Environmental Pollution, 130(2), 263-274, Retrieved from https://doi.org/10.1016/j.envpol.2003.11.016
Hirwa, H., Nshimiyimana, X.F., Tuyishime, H. and Shingiro, C. 2019. Impact of mining activities on waterquality status at wolfram mining and processing (WMP), Burera, Rwanda. Journal of Materials andEnvironmentalSciences, 10 (12), 1214-1220, Retrieved from https://www.jmaterenvironsci.com/Document/ vol10/vol10_N12/JMES-2019-10-120-Hirwa.pdf
Islam, K., Vilaysouk, X. and Murakami, S. 2020. Integrating remote sensing and life cycle assessment toquantify the environmental impacts of copper-silver-gold mining: A case study from Laos. Resources,Conservation and Recycling, 154, 104630, Retrieved from https://doi.org/10.1016/j.resconrec.2019.
104630Japan International Cooperation Agency (JICA). 2008. The geological mapping and mineral information
service project for promotion of mining industry in the Lao People's Democratic Republic. Retrieved
from https://openjicareport.jica.go.jp/pdf/11899895_01.pdf
Kyophilvong, P. 2009. Mining sector in Laos. Ide-Jetro, 69-100, Retrieved from https://www.ide.go.jp/library/English/Publish/Reports/Brc/pdf/02_ch3.pdf
Liang, N., Yang, L., Dai, J. and Pang, X. 2011. Heavy metal pollution in surface water of Linglong gold
mining area, China. Procedia Environmental Sciences, 10, Part A, 914-917, Retrieved from https://doi.
org/10.1016/j.proenv.2011.09.146
Mahato, K.M., Singh, G., Singh, K.P., Singh, K.A. and Tiwari, K.A. 2017. Assessment of mine water quality
using heavy metal pollution Index in a coal mining area of Damodar River Basin, India. Bulletin ofEnvironmental Contamination and Toxicology, 99, 54-61.
Mercado-Garcia, D., Beeckman, E., Van Butsel, J., Arroyo, N.D., Peña, M.S., Van Buggendhoudt, C., De
Saeyer, N., Forio, M.A.E., De Schamphelaere, K.A.C., Wyseure, G. and Goethals, P. 2019. Assessing
the freshwater quality of a large-scale mining watershed: The need for integrated approaches. Water, 11(9), 1-20, Retrieved from DOI https://doi.org/10.3390/w11091797
Tripathi, M.S. and Chaurasia, S. 2020. Detection of chromium in surface and groundwater and its bioabsorption using bio-wastes and vermiculite. Engineering Science and Technology, an International
Journal, 23 (5), 1153-1161, Retrieved from DOI https://doi.org/10.1016/j.jestch.2019.12.002
Vostroknutova, E. 2010. Lao PDR development report 2010 natural resource management for sustainable
development: Hydropower and mining. The World Bank.
Weiner, F.R. and Matthews, A.R. 2003. Measurement of water quality. Environmental Engineering, 81-106,
Butterworth-Heinemann, Retrieved from DOI https://doi.org/10.1016/b978-075067294-8/50005-1
World Atlas. 2019. What are the major natural resources of Laos? World Atlas, Retrieved from https://www.worldatlas.com/articles/what-are-the-major-natural-resources-of-laos.html
Wurl, J., Lamadrid, I.M., Mendez-Rodriguez, L. and Vargas, A.B. 2018. Arsenic concentration in the surface
water of a former mining area: The la junta creek, Baja California sur, Mexico. International Journal ofEnvironmental Research and Public Health, 15 (3), 437, Retrieved from DOI https://doi.org/10.3390/ijerph15030437
Xu, J., Jin, G., Mo, Y., Tang, H. and Li, L. 2020. Assessing anthropogenic impacts on chemical andbiochemical oxygen demand in different spatial scales with bayesian networks. Water, 12 (1), 246,Retrieved from DOI https://doi.org/10.3390/w12010246Ⓒ ISERD141