Impact assessment of solid waste dumping sites on soil and groundwater quality in Haridwar district, Uttarakhand, India

The present work aimed to evaluate the effects of municipal solid waste (MSW) dumping on the quality of soil and groundwater at six specific sites (S1-S6) located in the Haridwar district of Uttarakhand, India. An analysis of selected physicochemical and heavy metal characteristics (Cu, Zn, Fe, Mn, Cd, and Cr) was conducted on groundwater and soil samples collected between July 2022 and June 2023 using standard techniques. Furthermore, the composition of municipal solid waste (MSW) was also analysed, revealing a significant proportion of biodegradable waste in comparison to non-biodegradable wastes. The areas affected by urban and industrial activity showed markedly higher concentrations of physicochemical and heavy metal parameters in both soil and groundwater samples (p < 0.05). An study of groundwater revealed concentrations from BDL to 0.170 ± 0.008 mg/L (S6) , 0.034 ± 0.004 mg/L (S4) to 1.565 ± 0.048 mg/L (S6), 1.786 ± 0.089 mg/L (S4) to 10.630 ± 0.279 mg/L (S6), 0.096 ± 0.006 mg/L (S4) to 0.321 ± 0.005 mg/L (S6), and 0.110 ± 0.005 mg/L (S6) for Cu, Zn, Fe, Mn, and Cd mg/kg , respectively. Cr was detected at the BDL level in all groundwater samples from all sites. Findings revealed that metals exceeded the BIS range, with Iron over the limit at all sites, Manganese at S1, S2, and S6 sites, and Cadmium at S1, S2, S3, and S6 sites. The examination of the soil samples revealed concentrations ranging from 0.399 ± 0.125 mg/kg (S5) to 2.806 ± 0.083 mg/kg (S6), 1.207 ± 0.044 mg/kg (S5) to 3.813 ± 0.238 mg/kg (S2), 24.972 ± 1.128 mg/kg (S5) to 47.417 ± 1.713 mg/kg (S3), 2.297 ± 0.43 mg/kg (S5) to 14.641 ± 0.229 mg/kg (S2), and BDL (S4, S5, and S6) to 0.194 ± 0.291 mg/kg (S2) for their respective elements. The Cr content was BDL in all soil samples from all sites. Several metals over the BIS range were detected, including Cu at site S6, Zn at sites S1, S2, S3, S4, and S6, Fe at all sites and Mn at site S2. In S1-S6, the total bacterial population in the soil ranged from 397 ± 67 CFU to 459±88 CFU, with values of 442 ± 86 CFU, 404 ± 78 CFU, 459 ± 88 CFU, 397 ± 67 CFU, 405 ± 67 CFU, and 451 ± 77 CFU, respectively. The findings revealed soil and groundwater pollution caused by the elevated levels of heavy metals in the groundwater, rendering the water unfit for drinking. The study underscores the need of adopting effective waste management strategies to reduce the adverse effects of solid waste disposal sites. The results can guide the formulation of development policies and laws aimed at enabling the implementation of suitable solid waste management techniques.