Evaluating groundwater nitrate and other physicochemical parameters of the arid and semi-arid district of DI Khan by multivariate statistical analysis

ABSTRACT

Nitrate as an important water pollutant, causing eutrophication was analyzed in Pakistan at different water sources (hand pump (HP), bore hole (BH) and tube well (TW)) to assess the contamination level caused by NO₃⁻. NO₃⁻ concentrations in the HP water samples were 31 mg L⁻¹ to 59 mg L⁻¹, in BH 20 mg L⁻¹ to 79 mg L⁻¹ while in TW water samples it was between 29 to 55 mg L⁻¹. The association of NO₃⁻ with other selected parameter in groundwater can be determined by using statistical approaches. Different physicochemical parameters (pH, electrical conductivity (EC), temperature and dissolved oxygen (DO)) were studied in groundwater samples of the research district. The Pearson correlation coefficient (r) for groundwater characteristics were calculated. Hierarchical Cluster Analysis (HCA) was used to categorize samples based on their groundwater quality similarities and to find links between groundwater quality factors. The key relationship of the groundwater for HP samples on EC and TDS (r = 1) had a great correlation, while all other parameters correlations were lower (r = 0.40), BH's parameters on WT and WSD (r = 0.57), WT and pH (r = 0.57), EC and DO (r = 0.50), DO and TDS (0.50), EC and TDS (r = 1) had a quite high correlation, while all other parameters correlations were less than (r = 0.40), on the other hand, tube well parameters on TDS and EC (r = 1) had a perfect correlation, DO and pH (r = 0.75) parameters correlations were less than (r = 0.40).

GRAPHICAL ABSTRACT

KEYWORDS:

• Groundwater
• nitrate
• Hierarchical Cluster Analysis
• ion chromatography

Acknowledgements

The author is thankful to Pak-US Project (No.64/PAK-US/HEC/2015/04) PI providing laboratory and other facilities.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All data generated or analysed during this study are included in this published article (and its additional files). Additional data associated with a paper can be found when contacting to authors, thereafter it can be shared. Requests for material should be made to the corresponding authors.

Additional information

Funding

This research was funded by project nr T190087MIMV and European Commission, MLTKT19481R ‘Identifying best available technologies for decentralized wastewater treatment and resource recovery for India, SLTKT20427’ Sewage sludge treatment from heavy metals, emerging pollutants and recovery of metals by fungi and by project KIK 15392 and 15401 by European Commission by project No.1.1.1.2/VIAA/3/19/531 ‘Innovative technologies for stabilization of landfills—diminishing of environmental impact and resources potential in frames of circular economy’.