Department of Geography, Adamas University, Kolkata, West Bengal, 700126, India.
Environ Sci Pollut Res Int. 2021 Apr;28(13):15853-15869. doi: 10.1007/s11356-020-11655-6. Epub 2020 Nov 26.
Water quality is a critical environmental issue because all forms of life depend on the water. The present study primarily focused on the spatiotemporal trends of water quality in a section of the Bhagirathi-Hugli River, West Bengal, using geospatial technology and integrated statistical methods. For this purpose, 83 samples of 7 water parameters were analysed and compared them with Indian Standards (IS 2004), Environmental Protection Agency (EPA 2001) and World Health Organization (WHO 1993) for the protection of aquatic life and human consumption. Correlation, box and whisker plots, paired sample t test, water quality index (WQI), cluster analysis (CA) and principal component analysis (PCA) were applied as an integrated multivariate statistical approach to understanding the nature of water quality. Pollution sources were identified by PCA indicating different origins both naturally and anthropogenic sources. The box and whisker plots displayed the significantly spatiotemporal variations and concentration of the variables. The paired sample t test identified that the surface water quality varied significantly between the seasons with significant value p < 0.05. Cluster analysis grouped 83 monitoring sites into 4 clusters to identify the pollution status such as low, moderate, high and very high pollution sites. Principal component analysis confirmed that the first three PCs with eigenvalues are higher than 1 contributing 90.83% of total variability for various parameters. The conductivity, total dissolved solids (TDS), salt and pH were expressively influenced by the anthropogenic effect while the temperature, oxidation-reduction potential (ORP) and dissolved oxygen (DO) were affected by seasonal factors. Results of WQI ranged from 45.04 to 83.79, and an average value was 69.55 with 69% samples representing poor water quality for drinking and domestic purposes. It also indicates that the water quality of rural sites was better than industrial and urban sites in both seasons and also shows that it was better for the duration of the post-monsoon than pre-monsoon.
水质是一个至关重要的环境问题，因为所有形式的生命都依赖于水。本研究主要利用地理空间技术和综合统计方法，研究了印度西孟加拉邦一段 Bhagirathi-Hugli 河的水质时空变化趋势。为此，分析了 7 个水质参数的 83 个样本，并将其与印度标准 (IS 2004)、美国环保署 (EPA 2001) 和世界卫生组织 (WHO 1993) 进行了比较，以保护水生生物和人类消费。相关性、箱线图、配对样本 t 检验、水质指数 (WQI)、聚类分析 (CA) 和主成分分析 (PCA) 被应用于综合多变量统计方法，以了解水质的性质。主成分分析确定了污染源，表明存在不同的自然和人为来源。箱线图显示了变量的显著时空变化和浓度。配对样本 t 检验表明，地表水质量在季节之间存在显著差异，具有显著的 p 值<0.05。聚类分析将 83 个监测点分为 4 组，以识别污染状况，如低、中、高和极高污染点。主成分分析证实，前三个特征值大于 1 的主成分对各种参数的总变异性贡献了 90.83%。电导率、总溶解固体 (TDS)、盐度和 pH 值受人为影响显著，而温度、氧化还原电位 (ORP) 和溶解氧 (DO) 受季节因素影响。WQI 的结果范围从 45.04 到 83.79，平均值为 69.55，有 69%的样本表示饮用水和家庭用水水质较差。这也表明，无论是在雨季还是旱季，农村地区的水质都优于工业和城市地区，而且旱季过后的水质也优于旱季前。
