Hydrogeochemical Evolution and Heavy Metal Contamination in Groundwater of a Reclaimed Land on Zhoushan Island

Abstract

The need for valuable land has encouraged reclamation in coastal areas worldwide in the past decades. Land reclamation can alter the groundwater quality in coastal aquifers. The purpose of this study is to identify the effect of land reclamation on groundwater chemistry, especially the major ions, and heavy metals on Zhoushan Island, China. The subsurface media on the island is composed of two layers, i.e., an upper infill layer and an underlain clay layer. The upper layer is previously ocean and filled with various materials. The clay layer is the original marine sediment. The dominated Na and Cl ions in groundwater illustrate high salinity sources of groundwater in the subsurface of the reclaimed land. A mixing trend between seawater and river water of the groundwater in infill layer is also detected based on the ratios of Cl and Br. Though the heavy metal concentrations (Cd, Cr, Zn and Hg) are high in marine sediments, no significant releasing trends in the groundwater are detected in a short-term after reclamation (based on standard GB18668). Meanwhile, Fe-III concentrations in the aquifer have a strong correlation with precipitation events. Column desorption experiments and simulations indicate the Cd and Cr release from the sediment would pose a health risk when the groundwater in the infill layer being gradually flushed by fresh water. These results provide a foundation for the prediction of groundwater quality and are helpful for the future water management in a newly reclaimed land.

Experimental investigation of groundwater contamination by surface sources: Determination of adsorption capacity, diffusion, and sorption potential of selected anions in different soils

“…A similar trend was observed during sulfate adsorption with an increase in pH from 6.96 to 7.08 and 7.55 to 8.63, respectively, in soil‐1 and soil‐2. The same trend of pH variation was also reported by earlier studies (Zhang et al., ). The increase in pH could be attributed to the replacement of the hydroxyl group from the soil by the anions.…”

Groundwater Salinity Susceptibility Mapping Using Classifier Ensemble and Bayesian Machine Learning Models

“…While the climate change, rapid urban development, unsewered disposal, constructions, mining, and other industrial pollutants are constantly threatening the quality and quantity of groundwater; generally the oil and gas production, as well as agricultural practices of overusing pesticides and fertilizers more than any anthropogenic activities, are contributing to the groundwater contamination and scarcity [5]- [16]. Various salts (including nontoxic and toxic ions), minerals, heavy metals, microorganisms, pathogens, petroleum pollutants, and nutrients are among the major contaminators [17]- [22]. The salinity of groundwater may have various origins of natural and man-made causes [23].…”

Use of Heavy Metal Content and Modified Water Quality Index to Assess Groundwater Quality in a Semiarid Area

“…Many methods such as multivariate statistical techniques (e.g., cluster analysis, principal component analysis, and factor analysis) [13,14], hydro-geochemical evaluation [15,16], heavy metal indices (e.g., heavy metal pollution index, degree of contamination, heavy metal evaluation index, contamination factor, and health risk assessment) [17][18][19], and water evaluation indices [13] have been developed for assessing water quality considering physicochemical parameters. Grading water quality indicators largely depends on indicator concentration and the rate of relative toxicity.…”