title: Spatiotemporal changes of CVOC concentrations in karst aquifers: analysis of three decades of data from Puerto Rico.
abstract: We studied the spatial and temporal distribution patterns of Chlorinated Volatile Organic Compounds (CVOCs) in the karst aquifers in northern Puerto Rico (1982-2013). Seventeen CVOCs were widely detected across the study area, with the most detected and persistent contaminated CVOCs including trichloroethylene (TCE), tetrachloroethylene (PCE), carbon tetrachloride (CT), chloroform (TCM), and methylene chloride (DCM). Historically, 471 (76%) and 319 (52%) of the 615 sampling sites have CVOC concentrations above the detection limit and maximum contamination level (MCL), respectively. The spatiotemporal patterns of the CVOC concentrations showed two clusters of contaminated areas, one near the Superfund site "Upjohn" and another near "Vega Alta Public Supply Wells." Despite a decreasing trend in concentrations, there is a general northward movement and spreading of contaminants even beyond the extent of known sources of the Superfund and landfill sites. Our analyses suggest that, besides the source conditions, karst characteristics (high heterogeneity, complex hydraulic and biochemical environment) are linked to the long-term spatiotemporal patterns of CVOCs in groundwater.
authors.affiliation: Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA.
authors.forename: Xue
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA.
authors.forename: Reza
authors.initials: R
authors.lastname: Ghasemizadeh
authors.affiliation: Department of Civil Engineering and Surveying, University of Puerto Rico, Mayaguez, PR 00682, USA.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Padilla
authors.affiliation: Department of Civil Engineering and Surveying, University of Puerto Rico, Mayaguez, PR 00682, USA.
authors.forename: Celys
authors.initials: C
authors.lastname: Irizarry
authors.affiliation: Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115, USA.
authors.forename: David
authors.initials: D
authors.lastname: Kaeli
authors.affiliation: Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA. Electronic address: aalsha@coe.neu.edu.
authors.forename: Akram
authors.initials: A
authors.lastname: Alshawabkeh
mesh_terms: D004784:Environmental Monitoring; D060587:Groundwater / Q000737:chemistry*; D011647:Puerto Rico; D013750:Tetrachloroethylene / Q000032:analysis; D014241:Trichloroethylene / Q000032:analysis; D055549:Volatile Organic Compounds / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data
chemical_list: D055549:Volatile Organic Compounds; D014874:Water Pollutants, Chemical; D014241:Trichloroethylene; D013750:Tetrachloroethylene
keywords: CVOC; Groundwater contamination; Karst; Puerto Rico (USA); Spatiotemporal patterns