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Heavy Metal Index

Antimony leaching from polyethylene terephthalate (PET) plastic used for bottled drinking water

Nine PET bottled waters bought in Arizona were measured for antimony by ICP-MS, with a local tap water for comparison.

Nine PET bottled waters bought in Arizona were measured for antimony by ICP-MS, with a local tap water for comparison. As purchased, bottled-water antimony ranged from 0.095 to 0.521 ppb, with means of 0.195 ± 0.116 ppb at the start and 0.226 ± 0.160 ppb after three months at 22 °C. Heating one bottle to 80 °C raised antimony well above the 6 ppb USEPA maximum contaminant level, reaching 14.4 ppb after seven days, while pH from 6.3 to 8.3 and freezing did not. Microwave digestion of that bottle’s plastic found 213 ± 35 mg/kg antimony. Brand names appear in the methods and are omitted here; the paper’s brand ID numbers are used where a result is tied to one bottle.

Key numbers

AnalyteMatrixValueUnitStatisticNWhere
Sbdrinking water limit (USEPA/Ontario/Health Canada)6ppbregulatory_limitp.PDF p.2 (printed 552)
Sbdrinking water limit (Germany)5ppbregulatory_limitp.PDF p.2 (printed 552)
Sbdrinking water limit (EU)5ppbregulatory_limitp.PDF p.2 (printed 552)
Sbdrinking water limit (Japan)2ppbregulatory_limitp.PDF p.2 (printed 552)
Sbdrinking water limit (WHO)20ppbregulatory_limitp.PDF p.2 (printed 552)
SbICP-MS water0.004ppblodp.PDF p.3 (printed 553)
Sbnine Arizona PET bottled waters, as purchased0.095-0.521ppbrange9Fig. 1 p.PDF p.1 (printed 551)
Sbnine Arizona PET bottled waters, start of study0.195 ± 0.116ppbmean9Fig. 1 p.PDF p.1 (printed 551)
Sbnine Arizona PET bottled waters, after 3 months at 22 °C0.226 ± 0.160ppbmean9Fig. 1 p.PDF p.1 (printed 551)
SbTempe, Arizona tap water0.146 ± 0.002ppbmeanp.PDF p.3 (printed 553)
SbBrand 9 bottled water, Fig. 3 maximum cited13.9ppbmaxFig. 3 p.PDF p.6 (printed 556)
Sbsunlight-exposed Brand 9, 7 days, water about 35 °C0.37-0.61ppbrangetriplicateFig. 5 p.PDF p.5 (printed 555)

Methods (brief)

Bottles purchased summer 2006. Water transferred to acid-washed HDPE, acidified with HNO3, indium internal standard. Incubations at 22, 40, 60, and 80 °C. Screening matrix on brand ID 9: pH 6.3, 7.3, 8.3; control 48 h; frozen −20 °C 48 h; 80 °C 48 h; UV-PEN 254 nm for 6 h. Outdoor sun exposure 9-16 August 2006 with foil-wrapped controls. Piece leaching: 9.4 cm × 9.4 cm plastics in 1 L nanopure water at 80 °C up to 10 days.

Detection and reporting: Limit of detection 0.004 ppb; method reporting level 0.028 ppb. Handling blank <0.005 ppb. Precision within 3% (1s) on NIST 1640, NIST 1643e, and NRC SLRS-4.

Basis: Sb in water as ppb. PET content as mg/kg plastic and mg/cm2. Migration experiments are release into the bottled water or into nanopure water, not total content. The paper equates ppb with mg/L in the MCL sentence; the water concentrations are in the μg/L range that drinking-water MCLs use, and are transcribed in the printed unit ppb.

Evidence fitness

This source can support: Total Sb in southwestern US PET bottled water as purchased, as a range and mean; Temperature-dependent Sb release from PET into water; Total Sb and a few other elements in one PET bottle after digestion; Cited drinking-water Sb limits.

It cannot support: A full brand-level concentration table; Sb speciation; A certification limit; Sunlight as a large independent driver (the paper found only a small, non-significant difference versus a temperature-matched control).

Limitations

Per-brand as-purchased concentrations exist only as Fig. 1, so they were not transcribed bottle by bottle; the printed range and the two study means were entered, and individual rows were not all transcribed. One pH 7.3 control cell is a dash in Table 1 and was omitted. The 376 ppb figure is a complete-leach calculation, not a measurement. Chromium in the digest is total chromium, not chromium(VI). The paper prints the MCL unit as ppb and once as mg/L in the same sentence.

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