Assessment of surface water and groundwater quality and their associated human health risks around dumpsites, Cross River State, Southern Nigeria

Abstract

The present study evaluates surface water and groundwater and explores their associated human health risk around dumpsites in four Nigerian cities. Hence, groundwater (GW), surface water (SW), dumpsites leachate (CW) and rainwater (RW) samples were collected and analyzed for physicochemical parameters, major ions trace and rare earth elements using standard field and laboratory methods. Moreover, the study applied multivariate statistics, geochemical modeling, scatter plots and pollution indices. Elevated concentration of TDS, TH, Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻, HCO₃⁻, SO₄²⁻, NO₃⁻ and Al were obtained in the different water samples. REE data showed that the LREEs are higher compared to the HREEs, while the plots of REE data normalized to Post Archean Australian Shale (PAAS) revealed a middle REE enrichment relative to LREE and HREEs. Majority of the samples exhibits variable positive Europium, Cerium, Gadolinium and Erbium anomalies. The concentration of aluminum, iron and manganese were higher than MAL in some GW and SW samples, while in CW, Co, Cu and Zn were below their respective MAL. The major hydrochemical facies, were Ca²⁺–HCO₃⁻, Na⁺–Ca²⁺–HCO₃⁻, Na⁺–HCO₃⁻ and Na⁺–Cl⁻. The strong correlation between water pollution parameters suggests that those parameters were derived from common natural and anthropogenic sources. Furthermore, R-mode factor analysis and hierarchal cluster analysis indicated that the water chemistry was controlled by both water-rock interaction and anthropogenic activities. The pollution index for all the samples was low, suggesting that the water samples are suitable for human consumption, except for some samples with pollution index suggesting poor water quality for consumption and irrigation. Though the average daily dose for both adults and children were < 1, elevated hazard quotient > 1 values were observed in some samples, while hazard index values > 1 were also recorded. Carcinogenic values greater than 10⁻⁶ and 10⁻⁴ were observed for some samples due to the high Cd, Cr and Ni concentrations, suggesting potential health risk. The results showed that sustainable management measures are required to control open waste disposal so that water resources contamination can be effectively reduced.