Assessment of groundwater contamination from industrial effluents along Challawa River, Kano State, Nigeria

Abstract

Industrial effluents released into surface and subsurface environments pose a serious threat to groundwater quality, particularly in urban industrial corridors.This study investigates the extent of groundwater contamination arising from the discharge of industrial effluents into the Challawa River, Kano State, Nigeria. Water samples were collected from boreholes, hand-dug wells, and river points and analyzed for physico-chemical and heavy metal parameters following APHA standards. The results showed turbidity levels ranging from 320 to 1,050 NTU, total dissolved solids (TDS) from 850 to 1,600 mg/L, and electrical conductivity from 1,200 to 2,500 µS/cm. Heavy metals including chromium (0.28–0.35 mg/L), iron (1.2–2.4 mg/L), and sulphate (190–340 mg/L) exceeded WHO minimum standard and Nigerian Industrial Standards (NIS) limits. The findings indicate significant infiltration of effluents into shallow aquifers, posing health and environmental risks. Effective industrial waste management, routine groundwater monitoring, and strict regulatory enforcement are recommended to safeguard water resources and public health. The detected levels of heavy metals and other physicochemical parameters beyond permissible limits serve as evidence-based guidance for regulators to establish stricter effluent discharge limits for industries operating along the Challawa Industrial Estate. Such data also support the design of groundwater protection policies and land-use zoning regulations to prevent borehole drilling and agricultural irrigation near polluted zones. Furthermore, the study outcomes can aid in developing continuous groundwater-quality monitoring frameworks that ensure early detection of contamination plumes and safeguard potable water supplies. The results provide a scientific foundation for remediation programmes and the polluter-pays enforcement principle implemented by NESREA, while also guiding public awareness campaigns to encourage responsible waste-disposal practices in surrounding communities. In summary, the study contributes directly to evidence-based environmental decision-making, public-health protection, and sustainable water-resource management in Kano State and other industrial regions of Nigeria.