skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Impact of physical and chemical parameters on square wave anodic stripping voltammetry for trace Pb 2+ detection in water
Title: Impact of physical and chemical parameters on square wave anodic stripping voltammetry for trace Pb 2+ detection in water
Exposure to lead, a toxic heavy metal, in drinking water is a worldwide problem. Lead leaching from lead service lines, the main contamination source, and other plumbing materials is controlled by the plumbosolvency of water. Square wave anodic stripping voltammetry (SWASV) has been greatly explored as a rapid and portable technique for the detection of trace Pb 2+ ions in drinking water. However, the impact of water quality parameters (WQP) on the SWASV technique is not well understood. Herein, SWASV was employed to detect 10 μg L −1 Pb 2+ and determine trends in the stripping peak changes in simulated water samples while individually varying the pH, conductivity, alkalinity, free chlorine, temperature, and copper levels. The pH and conductivity were controlled using the buffer 3-( N -morpholino)propanesulfonic acid (MOPS), and NaNO 3 , respectively and kept at pH = 7.0 and conductivity = 500 μS cm −1 when exploring other WQPs. The working electrode, a gold-nanoparticle-modified carbon nanotube fiber cross-section (AuNP-CNT f -CS) electrode provided sufficiently sharp and prominent peaks for 10 μg L −1 Pb 2+ detection as well as good reproducibility, with a relative error of 5.9% in simulated water. We found that conductivity, and temperature had a proportional relationship to the peak height, and pH, alkalinity, free chlorine, and copper had an inverse relationship. In addition, increasing the copper concentration caused broadening and shifting of the Pb 2+ stripping peak. At extremely low conductivities (<100 μS cm −1 ), the voltammograms became difficult to interpret owing to the formation of inverted and distorted peaks. These trends were then also observed within a local drinking water sample in order to validate the results.  more » « less
Award ID(s):
2016484
PAR ID:
10340425
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
The Analyst
ISSN:
0003-2654
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ; ; et al (, ACS ES&T Water)
    We assessed the effect of redox conditions on the mobility of lead (Pb), copper (Cu), and iron (Fe) from sediments affected by acid mine drainage (AMD). This was accomplished by integrating laboratory microcosm experiments, aqueous chemistry, diffraction, and electron microscopy. Microcosm experiments underwent 3 consecutive 5 day redox phases: oxic-anoxicoxic. The sediments contained Fe (51,000 mg/kg), Pb (307 mg/kg), and Cu (30 mg/kg), and minerals such as Illite, albite, and goethite. Microscopy analyses revealed that Pb and Cu are associated with Al-silicates and jarosite. Iron release peaked under anoxic conditions (∼250 mg/L), then decreased in the second oxic phase (<70 mg/L). Extraction experiments confirmed that Pb and Cu are water-labile at pH 3.4 (Pb: 27 μg/L exceeding the United States Environmental Protection Agency drinking water action level of 15 μg/L, Cu: 75 μg/L), but less labile at pH 6.4 (Pb: 7 μg/L, Cu: 3 μg/L). DNA sequencing detected metal-tolerant fungal genera (Trichoderma, Fusarium, Penicillium, and Aspergillus) in the sediments. This study provides insights into the biogeochemical processes influencing the lability of metals in AMD-affected sites, which have relevant implications for risk assessment, remediation strategies, and recovery of critical minerals. 
    more » « less
  2. ; ; ; (, Environmental Science: Water Research & Technology)
    null (Ed.)
    A rapid and sensitive method is described for measuring perchlorate (ClO 4 − ), chlorate (ClO 3 − ), chlorite (ClO 2 − ), bromate (BrO 3 − ), and iodate (IO 3 − ) ions in natural and treated waters using non-suppressed ion chromatography with electrospray ionization and tandem mass spectrometry (NS-IC-MS/MS). Major benefits of the NS-IC-MS/MS method include a short analysis time (12 minutes), low limits of quantification for BrO 3 − (0.10 μg L −1 ), ClO 4 − (0.06 μg L −1 ), ClO 3 − (0.80 μg L −1 ), and ClO 2 − (0.40 μg L −1 ), and compatibility with conventional LC-MS/MS instrumentation. Chromatographic separations were generally performed under isocratic conditions with a Thermo Scientific Dionex AS16 column, using a mobile phase of 20% 1 M aqueous methylamine and 80% acetonitrile. The isocratic method can also be optimized for IO 3 − analysis by including a gradient from the isocratic mobile phase to 100% 1 M aqueous methylamine. Four common anions (Cl − , Br − , SO 4 2− , and HCO 3 − /CO 3 2− ), a natural organic matter isolate (Suwannee River NOM), and several real water samples were tested to examine influences of natural water constituents on oxyhalide detection. Only ClO 2 − quantification was significantly affected – by elevated chloride concentrations (>2 mM) and NOM. The method was successfully applied to quantify oxyhalides in natural waters, chlorinated tap water, and waters subjected to advanced oxidation by sunlight-driven photolysis of free available chlorine (sunlight/FAC). Sunlight/FAC treatment of NOM-free waters containing 200 μg L −1 Br − resulted in formation of up to 263 ± 35 μg L −1 and 764 ± 54 μg L −1 ClO 3 − , and up to 20.1 ± 1.0 μg L −1 and 33.8 ± 1.0 μg L −1 BrO 3 − (at pH 6 and 8, respectively). NOM strongly inhibited ClO 3 − and BrO 3 − formation, likely by scavenging reactive oxygen or halogen species. As prior work shows that the greatest benefits in applying the sunlight/FAC process for purposes of improving disinfection of chlorine-resistant microorganisms are realized in waters with lower DOC levels and higher pH, it may therefore be desirable to limit potential applications to waters containing moderate DOC concentrations ( e.g. , ∼1–2 mg C L −1 ), low Br − concentrations ( e.g. , <50 μg L −1 ), and circumneutral to moderately alkaline pH ( e.g. , pH 7–8) to strike a balance between maximizing microbial inactivation while minimizing formation of oxyhalides and other disinfection byproducts. 
    more » « less
  3. ; ; ; ; ; (, Environmental Science: Water Research & Technology)
    null (Ed.)
    This study investigated the reaction kinetics on the oxidative transformation of lead( ii ) minerals by free chlorine (HOCl) and free bromine (HOBr) in drinking water distribution systems. According to chemical equilibrium predictions, lead( ii ) carbonate minerals, cerussite PbCO 3(s) and hydrocerussite Pb 3 (CO 3 ) 2 (OH) 2(s) , and lead( ii ) phosphate mineral, chloropyromorphite Pb 5 (PO 4 ) 3 Cl (s) are formed in drinking water distribution systems in the absence and presence of phosphate, respectively. X-ray absorption near edge spectroscopy (XANES) data showed that at pH 7 and a 10 mM alkalinity, the majority of cerussite and hydrocerussite was oxidized to lead( iv ) mineral PbO 2(s) within 120 minutes of reaction with chlorine (3 : 1 Cl 2  : Pb( ii ) molar ratio). In contrast, very little oxidation of chloropyromorphite occurred. Under similar conditions, oxidation of lead( ii ) carbonate and phosphate minerals by HOBr exhibited a reaction kinetics that was orders of magnitude faster than by HOCl. Their end oxidation products were identified as mainly plattnerite β-PbO 2(s) and trace amounts of scrutinyite α-PbO 2(s) based on X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) spectroscopic analysis. A kinetic model was established based on the solid-phase experimental data. The model predicted that in real drinking water distribution systems, it takes 0.6–1.2 years to completely oxidize Pb( ii ) minerals in the surface layer of corrosion scales to PbO 2(s) by HOCl without phosphate, but only 0.1–0.2 years in the presence of bromide (Br − ) due the catalytic effects of HOBr generation. The model also predicts that the addition of phosphate will significantly inhibit Pb( ii ) mineral oxidation by HOCl, but only be modestly effective in the presence of Br − . This study provides insightful understanding on the effect of residual disinfectant on the oxidation of lead corrosion scales and strategies to prevent lead release from drinking water distribution systems. 
    more » « less
  4. ; (, Environmental Science: Water Research & Technology)
    Lead( iv ) oxide PbO 2 is one dominant solid phase in lead corrosion scales of drinking water distribution systems. Understanding the colloidal dispersion of PbO 2 is important for lead control in drinking water, especially under scenarios of switching the residual disinfectant from chlorine to chloramine. This study investigated the changes in lead release and colloidal dispersion from PbO 2(s) associated with the presence of natural organic matter (NOM), the introduction of chloramine, and the addition of a phosphate corrosion inhibitor in drinking water distribution systems. Experimental data showed that when NOM was present, the surface charges of PbO 2 exhibited a prominent negative shift, leading to colloidal dispersion of Pb( iv ) particles. The presence of chloramine did not significantly change the detrimental effects of NOM on the colloidal behavior of PbO 2 . In contrast, the addition of phosphate greatly reduced colloidal lead release in the size range between 0.1 and 0.45 μm, and limited lead release with colloidal sizes less than 0.1 μm to below 15 μg L −1 , i.e. , the U.S. EPA regulatory standard. The beneficial effects of phosphate addition are mainly attributed to the suppression in colloidal dispersion of Pb( iv ) particles. Meanwhile, the presence of phosphate also limits the reductive dissolution of PbO 2 via the formation of hydroxypyromorphite Pb 5 (PO 4 ) 3 OH particles. Results from this study suggest that phosphate limits the dispersion of PbO 2(s) by NOM and prevented the release of Pb( iv ) colloids into drinking water. 
    more » « less
  5. ; ; ; (, Pathogens)
    null (Ed.)
    Flint, MI experienced two outbreaks of Legionnaires’ Disease (LD) during the summers of 2014 and 2015, coinciding with use of Flint River as a drinking water source without corrosion control. Using simulated distribution systems (SDSs) followed by stagnant simulated premise (i.e., building) plumbing reactors (SPPRs) containing cross-linked polyethylene (PEX) or copper pipe, we reproduced trends in water chemistry and Legionella proliferation observed in the field when Flint River versus Detroit water were used before, during, and after the outbreak. Specifically, due to high chlorine demand in the SDSs, SPPRs with treated Flint River water were chlorine deficient and had elevated L. pneumophila numbers in the PEX condition. SPPRs with Detroit water, which had lower chlorine demand and higher residual chlorine, lost all culturable L. pneumophila within two months. L. pneumophila also diminished more rapidly with time in Flint River SPPRs with copper pipe, presumably due to the bacteriostatic properties of elevated copper concentrations caused by lack of corrosion control and stagnation. This study confirms hypothesized mechanisms by which the switch in water chemistry, pipe materials, and different flow patterns in Flint premise plumbing may have contributed to observed LD outbreak patterns. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email