Groundwater Selenium Level and its Enrichment Dynamics in Seawater Intrusion Area along the Northern Coastal Zones of Shandong Province, China

Abstract

The variation of groundwater properties caused by seawater intrusion, such as OH-, TDS, can potentially affect the groundwater Se levels. But there are no researches detailing the mechanism of groundwater selenium characteristics in seawater intrusion areas along coastal zones. Buzhuang town has been selected for study and groundwater is sampled to discuss the behavior of groundwater selenium with the intrusion of seawater. The groundwater Se levels range from 1.43 to 15.60 μg/L, with an average of 6.23 μg/L. All are within the limit of 10 μg/L except Wanglu village, but the local groundwater Se levels in 8 villages exceed the chronic criterion of 5 μg/L, and the Se levels in local groundwater are higher than those in the supplied water which has a non-seawater source. The groundwater Se levels have been shown to be elevated by seawater intrusion. The groundwater Se levels are positively correlated with Cl-, TDS, Br-, Na + , Mg 2+ , Ca 2+ and Fe and negatively correlated with pH. Ion competition effects and the Na-Mg-sulfate minerals play an important role in the adsorption and desorption for and , which are the important dynamic species for groundwater selenium enrichment. However, Ca and Fe ions have less contribution to groundwater Se variation because of the lower affinity for and and lesser content in groundwater of seawater intrusion areas.

The Enrichment Process of Groundwater Fluorine in Sea Water Intrusion Area of Gaomi City, China

“…The groundwater parameters of Cl − and TDS are often used to adequately classify water samples in sea water intrusion, and TDS > 1000 mg/L or Cl − > 250 mg/L is a sign of sea water intrusion (Liu et al 2018;Chen et al 2019b). The average of Cl − and TDS in the area underlain by Quaternary sediment indicates an obvious sea water intrusion.…”

“…OH − and F − have the same radius and recharges, and groundwater OH − often exchanges F − in minerals (Wang et al 2015;Chen et al 2019b). It is widely documented that the groundwater F − concentration increases with increasing pH (Ma et al 2014;Wang et al 2015;Guo et al 2015;Chen et al 2019b).…”

“…OH − and F − have the same radius and recharges, and groundwater OH − often exchanges F − in minerals (Wang et al 2015;Chen et al 2019b). It is widely documented that the groundwater F − concentration increases with increasing pH (Ma et al 2014;Wang et al 2015;Guo et al 2015;Chen et al 2019b). The groundwater in the area underlain by Quaternary sediments appears more alkaline due to sea water intrusion, and groundwater F − levels are positively correlated with pH (Figure 2).…”

Microbe–Mineral Interaction-Induced Microorganism-Augmented Permeable Reactive Barriers for Remediation of Contaminated Soil and Groundwater: A Review

“…The WHO suggested that the average daily intake of Se be ∼30–50 μg day –1 . Inadequate or excess Se intake will cause adverse effects on the human body (safety range of 40–400 μg day –1 ). , Some researchers tried to remediate groundwater contaminated with Se­(VI) and Se­(IV) with Bio-PRBs and achieved a satisfying removal effect.…”