SEGH Articles

Flux Based Management of a Groundwater Pollution: from Mass Flux Measurements to Regulatory Decisions

01 August 2011
Goedele Verrydt won the Springer / Hemphill Prize for Student Oral Presentation at SEGH 2011 in Ormskirk, UK.

 

Goedele Verreydt, M.Sc. in Environmental Engineering (2004), commenced her PhD in the Department of Biology at the University of Antwerp in January 2008. Her PhD research concerns the determination and calculation of groundwater contaminant mass fluxes in the frame of a groundwater management, which she performs in the research group Land and Water Management at the Flemish Institute for Technological Research (VITO), Mol, Belgium.

The management of contaminated groundwater is very challenging. Most decisions regarding groundwater pollutions are driven by contaminant concentrations. Since concentration estimates may be highly uncertain and do not include the fluctuations caused by spatially and temporally varying hydrologic conditions, these strategies can be improved by additionally considering contaminant mass fluxes (mass of contaminants passing per unit time per unit area) and contaminant mass discharges (sum of all mass flux measures across an entire plume). The contaminant mass that effectively reaches a downgradient receptor, determines the actual risks for the receptor and should therefore be monitored on site. The combined monitoring of contaminant mass fluxes and groundwater fluxes along a control plane is possible with Passive Flux Meters (PFMs), recently developed passive sampling devices that are installed in monitoring wells for a certain period of time.

 

The main objectives of this study are:

  • to delineate a robust interpretation method for the measurement and calculation of groundwater contaminant fluxes, based on mass flux measurement with Passive Flux Meters (PFMs);
  • to define a clear strategy that supports regulatory decisions in a flux and risk based groundwater management.

The PFM consists of a permeable sorbent infused with soluble tracers packed in a nylon mesh tube. The measurements of the captured contaminants and the remaining resident tracer on the sorbent are used to estimate respectively contaminant and groundwater fluxes.

To calibrate and validate the PFMs, lab as well as field experiments are performed. In addition, the measured water fluxes and contaminant mass fluxes are compared to the results obtained by traditional measurement techniques. The proposed management strategy is based on a source-path-receptor approach.

The PFM has proven to be a valuable instrument for the measurement of contaminant mass flux in groundwater. The extrapolation options of the PFM flux data are defined. Mass discharge can be estimated by integrating the PFM mass flux data throughout the control plane, which converts the individual flux values to a time-stamped cumulative flux (or discharge value). Further, a theoretical framework for a flux based management strategy is set by introducing the term CMDmax (maximum accepted contaminant mass discharge) at a predefined plane of compliance, i.e. a control plane orthogonal to the main flow direction and upgradient the receptor. The proposed strategy includes remedial action if the CMDmax is exceeded.

 G. Verreydt1,2, I. Van keer1 and J. Bronders1

1VITO, Land and Water Management, Boeretang 200, 2400 Mol, Belgium

2Artesis University College of Antwerp, Paardenmarkt 92, 2000 Antwerpen

 goedele.verreydt@vito.be

 Figure shows Mrs. Verreydt retrieving a PFM during a field demonstration in Rijmenam, Belgium.

 Annable, L.D., K. Hatfield, J. Cho, H. Klammler, B.L. Parker, J.A. Cherry and P.S.C. Rao. 2005. Field-Scale Evaluation of the Passive Flux Meter for Simultaneous Measurement of Groundwater and Contaminant Fluxes. Environmental Science & Technology 39(18): 7194-7201.     

Verreydt, G., Bronders, J., Van Keer, I., Diels, L. & Vanderauwera, P. (2010) Passive samplers for monitoring VOCs in groundwater and the prospects related to mass flux measurements. Ground Water Monitoring and Remediation 30(2): 114-126.

Keep up to date

Submit Content

Members can keep in touch with their colleagues through short news and events articles of interest to the SEGH community.

Science in the News

Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

  • The society for environmental Geochemistry and health (SEGH): a retrospect 2019-02-22
  • Air quality and PM 10 -associated poly-aromatic hydrocarbons around the railway traffic area: statistical and air mass trajectory approaches 2019-02-19

    Abstract

    Diesel engine railway traffic causes atmosphere pollution due to the exhaust emission which may be harmful to the passengers as well as workers. In this study, the air quality and PM10 concentrations were evaluated around a railway station in Northeast India where trains are operated with diesel engines. The gaseous pollutant (e.g. SO2, NO2, and NH3) was collected and measured by using ultraviolet–visible spectroscopy. The advanced level characterizations of the PM10 samples were carried out by using ion chromatography, Fourier-transform infrared, X-ray diffraction, inductively coupled plasma optical emission spectrometry , X-ray photoelectron spectroscopy, field-emission scanning electron microscopy with energy-dispersive spectroscopy, and high-resolution transmission electron microscopy with energy-dispersive spectroscopy techniques to know their possible environmental contaminants. High-performance liquid chromatography technique was used to determine the concentration of polycyclic aromatic hydrocarbons to estimate the possible atmospheric pollution level caused by the rail traffic in the enclosure. The average PM10 concentration was found to be 262.11 µg m−3 (maximum 24 hour) which indicates poor air quality (AQI category) around the rail traffic. The statistical and air mass trajectory analysis was also done to know their mutual correlation and source apportionment. This study will modify traditional studies where only models are used to simulate the origins.

  • The geochemistry of geophagic material consumed in Onangama Village, Northern Namibia: a potential health hazard for pregnant women in the area 2019-02-18

    Abstract

    Ingestion of geophagic materials might affect human health and induce diseases by different ways. The purpose of this study is to determine the geochemical composition of geophagic material consumed especially by pregnant women in Onangama Village, Northern Namibia and to assess its possible health effects. X-ray fluorescence and inductively coupled plasma mass spectrometry were used in order to determine the major, and trace elements as well as anions concentrations of the consumed material. The geochemical analysis revealed high concentrations of aluminium (Al), calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), potassium (K), sodium (Na), and silica (Si); and trace elements including arsenic (As), chromium (Cr), mercury (Hg), nickel (Ni) and vanadium (V) as well as sulphate (SO42−), nitrate (NO3), and nitrite (NO2) anions comparing to the recommended daily allowance for pregnant women. The pH for some of the studied samples is alkaline, which might increase the gastrointestinal tract pH (pH < 2) and cause a decrease in the bioavailability of elements. The calculated health risk index (HRI > 1) revealed that Al and Mn might be a potential risk for human consumption. Based on the results obtained from the geochemical analysis, the consumption of the studied material might present a potential health risk to pregnant women including concomitant detrimental maternal and foetal effects.