Machine-learning models to map pH and redox conditions in groundwater in a layered aquifer system, Northern Atlantic Coastal Plain, eastern USA

DeSimone, Leslie A.; Pope, Jason P.; Ransom, Katherine Marie

doi:10.1016/j.ejrh.2020.100697

Cited by 21 publications

(18 citation statements)

References 55 publications

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“…Generally drinking water having pH < 7 is measured as acidic, and pH > 7 is considered basic. The normal range for pH in surface water systems is 6.5 to 8.5 and for groundwater aquifers 6 to 8.5 [74][75][76]. Unlike the Niger Delta Basin, groundwater in coastal basins of southwestern Nigeria is slightly alkaline.…”

Section: Physical Chemistrymentioning

confidence: 99%

Detailed Hydrogeological and Hydrochemical Reassessment of Coastal Basins of Southwestern Nigeria

2021

Geol Earth Mar Sci

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prolonged residence time in the aquifer and saltwater intrusion account for the variability of hydrochemistry of groundwater in coastal aquifers [1,[11][12][13][14]. The hydrochemistry of coastal aquifers of southwestern Nigeria is highly variable due to variation in geological configurations and human activities. Groundwater contamination stemming from human activities, and inadequate sewage discharge is on the rise in Nigeria [15][16][17]. Consequently, groundwater utilized for domestic uses is problematic and hence calls for scientific scrutiny. Examining hydrochemistry and groundwater quality in coastal regions is crucial to monitor and detect groundwater contaminants sources [18][19][20][21]. Groundwater quality analysis in Abeokuta South, Nigeria by Emenike, Nnaji [17] showed that water quality parameters exhibited wide variations from location to location. Sodium, magnesium, iron (++), and EC showed the most violation of drinking water quality standards. Anthropogenetic actions are escalating threat to groundwater quality and thus call for routine monitoring of groundwater in Abeokuta. Statistical and hydrochemical modelling of groundwater quality southwestern Nigeria showed a conjunctive imprint of anthropogenic and geogenic activities influencing the increasing dissolved chemical constituents in the groundwaters

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Section: Physical Chemistrymentioning

confidence: 99%

Detailed Hydrogeological and Hydrochemical Reassessment of Coastal Basins of Southwestern Nigeria

2021

Geol Earth Mar Sci

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“…Average influent groundwater quality characteristics within each cluster compared to the required influent water quality for certification under NSF P473 are provided in Table 1. Groundwater in clusters B and C was significantly below the certified pH range, typical of the acidic conditions of surficial aquifers in the North Carolina Coastal Plain (DeSimone et al, 2020). This study was approved by the University of North Carolina Institutional Review Board (IRB Study No.…”

Section: Study Area and Participant Recruitmentmentioning

confidence: 99%

Longitudinal assessment of point‐of‐use carbon filters for removal of per‐ and polyfluoroalkyl substances from private well water

et al. 2021

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Eighteen private well users in North Carolina were recruited to test the performance of under-sink, activated carbon block water filters to remove per-and polyfluoroalkyl substances (PFAS). Monthly sampling was conducted for 8 months. Filters were certified for removal of perfluorooctanoic acid and perfluorooctanesulfonic acid under NSF International certification P473, but not for additional short-chain perfluoroalkyl acids or perfluoroalkyl ether acids (PFEAs) evaluated in this study. Out of 47 targeted analytes, 17 PFAS were detected in filter influent samples (influent P PFAS 4.7-131 ng/L). Mixed-effects Tobit regression models showed that the filters effectively removed 97%-99% of all influent PFAS, including short-chain PFEAs, for the entire manufacturer-recommended lifetime of the device. The prevalence of PFAS above the minimum reporting limits was reduced by 99.5%, and the prevalence of any PFAS above the method detection limits was reduced by 92%. The results provide increased confidence in NSF P473-certified filters for the removal of PFAS from private well water.activated carbon, PFAS, point-of-use water treatment, private wells | INTRODUCTIONPer-and polyfluoroalkyl substances (PFAS)-including perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonic acids (PFSAs) (together referred to as perfluoroalkyl acids (PFAAs)), and replacement perfluoroalkyl ether acids (PFEAs)-have generated concern in recent decades for their widespread environmental

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“…Several studies have used borate ions as a typical buffer solution to mimic groundwaterrelevant pH conditions (6.0-8.5) owing to their pH buffering capacity being in a range of 8.0-10.0 [26,27]. Borate ions were recently found to stimulate PMS activity or induce PMS depletion resulting in accelerating or decelerating the degradation of target compounds depending on its concentrations [24,28].…”

Section: Introductionmentioning

confidence: 99%

Role of Borate Buffer in Organic Degradation by Peroxymonosulfate in the Presence of Metal Oxides

Park

Kim

2021

Water

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The effects of borate ions on the reactivity of peroxymonosulfate (PMS) during organic degradation in the presence of metal oxides were examined. The metal oxides exhibited catalytic abilities for the degradation of carbamazepine (CBZ) but not for phenol (PN). Scavenging experiments revealed the absence of radical generation during PN degradation in the presence of the various metal oxides and borate buffer. This indicated that the borate buffer hindered the catalytic abilities of the metal oxides for producing radicals via the PMS oxidant, especially during the faster degradation of compounds such as PN. Various concentrations of borate ions were assessed for enabling pH control and permitting catalytic activity. Fe2O3 was found to accelerate and inhibit PN degradation at borate-ion concentrations of 2 mM and 5–20 mM, respectively. Only the 20 mM borate-ion solutions were successful at maintaining the initial pH for 2 d. Phosphate buffer, which was examined as an alternative, also disrupted radical formation but not as considerably as that of the borate ions with metal oxides. This study demonstrates the significance of enabling pH control and permitting the catalytic activity for ensuring the effective use of oxyanions as buffers.

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Machine-learning models to map pH and redox conditions in groundwater in a layered aquifer system, Northern Atlantic Coastal Plain, eastern USA

Cited by 21 publications

References 55 publications

Detailed Hydrogeological and Hydrochemical Reassessment of Coastal Basins of Southwestern Nigeria

Detailed Hydrogeological and Hydrochemical Reassessment of Coastal Basins of Southwestern Nigeria

Longitudinal assessment of point‐of‐use carbon filters for removal of per‐ and polyfluoroalkyl substances from private well water

Role of Borate Buffer in Organic Degradation by Peroxymonosulfate in the Presence of Metal Oxides

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