title: Levels of perfluorochemicals in water samples from Catalonia, Spain: is drinking water a significant contribution to human exposure?
abstract: OBJECTIVE
  In recent years, due to a high persistence, biomagnification in food webs, presence in remote regions, and potential toxicity, perfluorochemicals (PFCs) have generated a considerable interest. The present study was aimed to determine the levels of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and other PFCs in drinking water (tap and bottled) and river water samples from Tarragona Province (Catalonia, Spain).
  
  
  METHODS
  Municipal drinking (tap) water samples were collected from the four most populated towns in the Tarragona Province, whereas samples of bottled waters were purchased from supermarkets. River water samples were collected from the Ebro (two samples), Cortiella, and Francolí Rivers. After pretreatment, PFC analyses were performed by HPLC-MS. Quantification was done using the internal standard method, with recoveries between 68% and 118%.
  
  
  RESULTS
  In tap water, PFOS and PFOA levels ranged between 0.39 and 0.87 ng/L (0.78 and 1.74 pmol/L) and between 0.32 and 6.28 ng/L (0.77 and 15.2 pmol/L), respectively. PFHpA, PFHxS, and PFNA were also other detected PFCs. PFC levels were notably lower in bottled water, where PFOS could not be detected in any sample. Moreover, PFHpA, PFHxS, PFOA, PFNA, PFOS, PFOSA, and PFDA could be detected in the river water samples. PFOS and PFOA concentrations were between <0.24 and 5.88 ng/L (<0.48 and 11.8 pmol/L) and between <0.22 and 24.9 ng/L (<0.53 and 60.1 pmol/L), respectively.
  
  
  CONCLUSIONS
  Assuming a human water consumption of 2 L per day, the daily intake of PFOS and PFOA by the population of the area under evaluation was calculated (0.78-1.74 and 12.6 ng, respectively). It was found that drinking water might be a source of exposure to PFCs as important as the dietary intake of these pollutants.
  
  
  CONCLUSIONS
  The contribution of drinking water (tap and bottled) to the human daily intake of various PFCs has been compared for the first time with data from dietary intake of these PFCs. It was noted that in certain cases, drinking water can be a source of exposure to PFCs as important as the dietary intake of these pollutants although the current concentrations were similar or lower than those reported in the literature for surface water samples from a number of regions and countries.
  
  
  CONCLUSIONS
  Further studies should be carried out in order to increase the knowledge of the role of drinking water in human exposure to PFCs.
authors.affiliation: Man-Technology-Environment Research Center (MTM), Department of Natural Sciences, Orebro University, 701 82 Orebro, Sweden.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Ericson
authors.forename: Martí
authors.initials: M
authors.lastname: Nadal
authors.forename: Bert
authors.initials: B
authors.lastname: van Bavel
authors.forename: Gunilla
authors.initials: G
authors.lastname: Lindström
authors.forename: José L
authors.initials: JL
authors.lastname: Domingo