Dataset on assessment of River Yamuna, Delhi, India using indexing approach

The objective of the present study is to investigate the status of pollution load in River Yamuna, Delhi. The 13 sites for sampling, spread through the Delhi stretch of Yamuna, starting from the Wazirabad barrage till the Okhla barrage has been selected. Physicochemical parameters such as pH, temperature, DO (Dissolved oxygen), TDS (Total dissolved solids), salinity and conductivity were determined. The concentration of heavy metals (Cd, Ni, Zn, Fe, Cu, Pb, and Cr,) were assessed and found to be (0.03, 0.025, 1.365, 6.175, 0.08, 0.02, and 0.03) respectively. Varying concentration of heavy metals was found due to the widespread discharge of industrial effluents into the river. The overall mean concentration of heavy metals was observed in the following order Fe > Zn > Cu > Ni > Cr > Pb > Cd. It can be concluded that our study area as a whole is critically polluted in terms of mean Fe concentration (6.175 mg/L) due to pollutant load from various anthropogenic activities and need treatment before further use. This dataset is beneficial for policymakers, and researchers in the field of River Yamuna water quality management.


Subject area
Environmental Science More specific subject area Water monitoring, quality Type of data of the studied river stretch. The value of this parameter from Wazirabad to Okhla barrage, after joining Shahdara drain was observed in the range of 0.5-3.6 mg/l which reflects that DO is always violating the prescribed standard of 5.0 mg/l.
Heavy metal pollution Index (HPI) method, is an effective tool to characterize the surface water pollution, and show the composite influence of individual heavy metal on the overall quality of water.
HPI calculated is far above the critical index limit of 100, that indicates the water is critically polluted with respect to heavy metals. The other reason is of deterioration of Yamuna River water quality in Delhi stretch especially after Wazirabad barrage is due to unabated discharges of wastewater predominantly from domestic sources into the river.

Data
This dataset contains 4 Tables and 9 Figures that represent pollution load in River Yamuna, Delhi, India. Fig. 1 and Table 1 shows the sampling points of the study area. Table 2 and Figs. 2-8 shows the physicochemical characterization determined using standard methodologies [1]. Table 3 and Fig. 9 shows the mean heavy metal concentration and limits prescribed by World Health Organization, Central pollution control Board [4] and Bureau of Indian Standards [2,3]. Heavy metal pollution index and correlation coefficient of the samples are shown in Table 4 and Table 5 respectively.

River Yamuna
The river Yamuna is of glacial origin and is the sub-basin of the Ganga river system. Out of the total catchment area of 861,404 km 2 of the Ganga basin, the Yamuna river and its catchment together contributes to a total of 366,223 km 2 area (catchment basin area in various states accounts for  345,848 km 2 and Yamuna river area is 20,375 km 2 ), which is 42.5% of total Ganga River Basin and 10.7% of the total geographical landmass of the country reported by CPCB [4].

Sample collection
This work was a cross-sectional study. The basis for selection of sampling locations was the changeability within the river stretch considering the variations in the hydrological regimes, pollution and biodiversity characteristics. The specific study sites for sample collection were identified after carrying out the investigation survey of the study area in January 2018. A total of 13 sites from Longitudes 28°45N to 28°30 0 N and Latitudes 77°13 0 E to 77°21 E were selected including various drains falling into River Yamuna and industrial areas with respect to the location of contaminant sources, the point of sewage discharge and the ease of sampling (see in Fig. 1 and Table 1). The

Physicochemical analysis
All chemicals used in the analysis of samples were of analytical grade and obtained from Merck, India. De-ionized water was used in various water quality protocols followed in the study. Physicochemical parameters including Turbidity, pH, Temperature, conductivity, TDS, Salinity, DO determined using APHA method and cross checked by water analysis kit.

Heavy metal analysis
Heavy metal determined by following the method reported by Bhardwaj et al. [5]. A 50 mL of wellmixed, acid preserved samples were taken in an acid-washed beaker and 10 mL conc. HNO 3 was added to it. The mixture was digested on a hot plate at 90°C till the volume got reduced to 10-20 mL. Final volume was made up to 50 mL by addition of de-ionized water that was followed by filtration  using Whatman no. 42 filter paper. The digested filtrates were used for the metal quantification using Atomic Absorption Spectrophotometer (model 4141 make: Electronic Corporation of India Limited), with setting of different characteristic wavelengths of metals using hollow cathode lamps and directly aspirating the digested samples into air-acetylene flame. The instrument was calibrated by analyzing known concentration of heavy metals. Standard solutions (1000 mg/L) procured from Merck were serially diluted to obtain the desired concentrations and for each metal, a multi-point calibration graph was prepared. During the analysis, a blank run was performed after every 10 samples to   examine the instrument's performance for minimization of any errors. The concentrations of each heavy metal in every sample were determined three times, and the results were expressed as the mean concentration of heavy metal in the given sample.

Data evaluation
The aggregate influence of individual heavy metal on the overall quality of River Yamuna water was calculated using Heavy metal pollution index (HPI). Various researchers [5,8,9] reported that, HPI is a rating approach that assigns weightage (W i ) to every parameter, reflecting the relative importance of individual quality considerations in a composite way or Wi can be assessed by making values inversely proportional to the recommended standard (S i ) for the corresponding parameter. The value of HPI lies between zero and one. The highest tolerant value for drinking water (S i ) refers to the maximum allowable concentration in drinking water in the absence of any alternate water source. The maximum desirable value (I i ) indicates the standard limits for the same parameters in drinking water. For computing HPI, the Bureau of Indian Standards (BIS) for drinking water for each heavy metal (chemical parameter) in g/L was considered. Mohan et al. (1996) reported the HPI as follows: where, Q i is the sub-index of the i th parameter and W i is the unit weightage of the i th parameter and n is the considered parameters in the analysis. The unit weightage (Wi) of the parameter is calculated using Eq. (2), where, S i the maximum allowable recommended standard for i th parameter and k is the constant of proportionality. The sub-index (Qi) of the parameter is calculated using Eq. (3)