Water chemistry and estimation of local geochemical background values of elements in headwater streams of Ken–Betwa catchment of Yamuna River, India

Abstract

The paper presents a geochemical approach to estimating the local background values of major ionic solutes and trace elements in headwater streams. Understanding the natural geochemical properties of each surface water body is essential for tracking environmental changes, identifying anthropogenic influences, and establishing baseline conditions for water quality management. This research aims to evaluate the elemental concentrations, water quality, and background values (BGVs) of stream water through systematic sampling, laboratory analysis, and hydrogeochemical and statistical interpretations. Water samples were analyzed for hydrochemical solutes such as major cations and anions using standard procedures, whereas concentrations of 44 trace elements, including heavy metals and metalloids, were determined using inductively coupled plasma mass spectrometry (ICP-MS). Water samples were collected in places that were unaffected by industrial or mining activity, as well as in generally clean areas. Statistical techniques were employed to distinguish between natural variability and potential human impacts. Hence, the mean + 2SD was then used to determine the BGV. In addition, spatial distribution maps of hydrochemical parameters were used to identify potential sources of contamination. The obtained concentrations were then compared to global water quality standards. The calculated BGVs revealed critical concentration levels of Al and Fe that surpassed the maximum limitations set by the legislation. These significantly elevated levels may constitute a health risk to people, particularly in rural locations where they rely solely on stream water and the aquatic environment. Heavy metals and metalloids including As, Cr, Cd, Pb, Ni, Hg, Zn, Cu, and Mn are found in trace amounts or below detection limits and pose no threat to the environment or human health. The levels of dissolved REEs in water samples are relatively low, indicating a geologic source. The proposed BGVs will serve as a reference to determine the impact of human activities (such as industrial discharges, agricultural runoff, and urban expansion) on water quality at the local level. The geochemical study of water also provides a robust framework for assessing the health of public and aquatic ecosystems and designing effective environmental management plans.