efsa-opinion-chromium-food-drinking-water
efsa-opinion-chromium-food-drinking-water
efsa-opinion-chromium-food-drinking-water
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Chromium in <strong>food</strong> and <strong>drinking</strong> <strong>water</strong><br />
average found at a few mg/kg levels. Rare crocoite (PbCrO 4 ) is the only mineral where Cr(VI) occurs<br />
naturally. Soils from the weathering of basalt, serpentine and ultramafic rocks, and phosphorites may<br />
contain <strong>chromium</strong> at levels as high as 3500 mg/kg, whereas soils from degradation of granite or<br />
sandstone rocks normally have <strong>chromium</strong> only at levels of a few tens of mg/kg. Chromium<br />
concentrations in thousands of USA and Canadian soil samples were reported to range from 1 to<br />
2000 and from 5 to 1500 mg/kg, respectively, with corresponding geometric means of 37 and<br />
43 mg/kg (WHO, 1988; ATSDR, 2012). Examples of hot spots can be found, for instance associated<br />
with old chromite mining sites; <strong>chromium</strong> has also been detected at a very high level (43 000 mg/kg)<br />
in soil at the Butterworth Landfill site in Grand Rapid City, Michigan. The use of chromated copper<br />
arsenate (CCA) as an outdoor wood preservative may be a cause for soil contamination. In 1994 and<br />
1995, <strong>chromium</strong> was detected in sediments obtained from the coastal <strong>water</strong>s of the eastern U.S.<br />
seashore at concentrations lower than 0.2 mg/g (Hyland et al., 1998).<br />
Examples of Cr(VI) occurrence from incidental anthropogenic sources<br />
As human exposure to toxic Cr(VI) compounds, several of which are quite soluble, is a matter of<br />
health concern, investigations and monitoring activities have been and are performed in different parts<br />
of the world, especially focused on assessing the chemical presence and levels in <strong>drinking</strong> <strong>water</strong> and<br />
its sources. From the generic examples described hereafter, <strong>drinking</strong> <strong>water</strong> seems to be the matrix of<br />
concern with respect to a potential human exposure deriving from an undetected accidental<br />
contamination.<br />
An accidental release of Cr(VI) from a chemical plant into the atmosphere occurred in August 2011 in<br />
Kooragang Island (Newcastle, New South Wales). The aerosol emission carrying Cr(VI) was<br />
deposited downwind of the stack, mostly on and around the facility. The spill continued for<br />
approximately 20 minutes. The original Cr(VI) emission estimate of 10-20 kg was subsequently<br />
revised to an estimated 1 kg of Cr(VI) which, in fact, rained down over the Orica plant; another<br />
35-60 g fell out over the suburb of Stockton (Orica, 2012), whose residents were therefore potentially<br />
exposed to the contaminated aerosol. Approximately 20 workers at the plant were exposed as well as<br />
70 nearby homes in Stockton.<br />
The contamination of <strong>drinking</strong> <strong>water</strong> in the southern California town of Hinkley ensued from a<br />
prolonged ground<strong>water</strong> contamination (EWG, 2005; Sutton, 2010). At the center of the case was a<br />
facility called the Hinkley compressor station, part of a long natural gas pipeline. Between 1952 and<br />
1966, the compressor station used <strong>water</strong> containing Cr(VI) compounds to fight corrosion in the<br />
machinery. Some Cr(VI)-contaminated waste<strong>water</strong>, discharged to unlined ponds at the site, percolated<br />
into the ground<strong>water</strong>, affecting a large area near the plant. Average background Cr(VI) levels in<br />
ground<strong>water</strong> were recorded as 1.2 µg/L (total <strong>chromium</strong> 1.5 µg/L) with a peak of 3.1 µg/L (total<br />
<strong>chromium</strong> 3.2 µg/L) (PG&E, 2007; CA EPA, 2008).<br />
A contaminated ground<strong>water</strong> plume originating from unknown source(s) allegedly composed of<br />
hazardous substances that were released into the Edwards-Trinity aquifer was detected at Midland<br />
(Texas), a community of approximately 114 000 people. At the time of the report by Cook (2010), the<br />
plume had an extension of a few kilometres and was situated under approximately 105 ha of<br />
residential and commercial land. Based on the results of a domestic <strong>drinking</strong> <strong>water</strong> well, an extensive<br />
ground<strong>water</strong> sampling was performed in 2009. The ground<strong>water</strong> plume contained elevated<br />
concentrations of total <strong>chromium</strong> including Cr(VI), that exceeded the U.S. EPA maximum<br />
contaminant limit (MCL) of 0.1 mg/L for total <strong>chromium</strong> and Cr(VI) in many active domestic <strong>water</strong><br />
wells: in particular, a large proportion of samples contained total <strong>chromium</strong> and/or Cr(VI) forms in the<br />
range 500-5000 µg/L.<br />
According to Vasilatos et al. (2008), total <strong>chromium</strong> and Cr(VI) were measured in the Thiva-Tanagra-<br />
Malakasa basin, Eastern Sterea Hellas, Greece. In the area, which is known for a 40-year long<br />
industrial activity, <strong>chromium</strong> levels as high as 80 and 53 µg/L were found in the urban <strong>drinking</strong> <strong>water</strong><br />
supplies of Oropos and Inofyta, respectively. The pollution of ground<strong>water</strong> by Cr(VI) in the majority<br />
of <strong>water</strong> wells in the Thiva-Tanagra-Malakasa basin was related to the widespread industrial activity,<br />
the use of hexavalent <strong>chromium</strong> in various processes, and the discharges of Cr-containing wastes. In<br />
another study (Vasilatos et al., 2010), hexavalent <strong>chromium</strong> was detected in ground<strong>water</strong> systems in<br />
EFSA Journal 2014;12(3):3595 19