This study makes a new estimate of the global historical production for perfluorooctane sulfonyl fluoride (POSF), and then focuses on producing a first estimate of the global historical environmental releases of perfluorooctane sulfonate (PFOS). The total historical worldwide production of POSF was estimated to be 96,000 t (or 122,500 t, including unusable wastes) between 1970-2002, with an estimated global release of 45,250 t to air and water between 1970-2012 from direct (manufacture, use, and consumer products) and indirect (PFOS precursors and/or impurities) sources. Estimates indicate that direct emissions from POSF-derived products are the major source to the environment resulting in releases of 450-2700 t PFOS into wastewater streams, primarily through losses from stain repellent treated carpets, waterproof apparel, and aqueous fire fighting foams. Large uncertainties surround indirect sources and have not yet been estimated due to limited information on environmental degradation, although it can be assumed that some POSF-derived chemicals will degrade to PFOS over time. The properties of PFOS (high water solubility, negligible vapor pressure, and limited sorption to particles) imply it will reside in surface waters, predominantly in oceans. Measured oceanic data suggests approximately 235-1770 t of PFOS currently reside in ocean surface waters, similar to the estimated PFOS releases. Environmental monitoring from the 1970s onward shows strong upward trends in biota, in broad agreement with the estimates of use and emissions made here. Since cessation of POSF production by 3M in 2002, a reduction in some compartments has been observed, although current and future exposure is dependent on emission routes, subsequent transport and degradation.
This paper presents data from a survey of polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) concentrations in 191 global background surface (0-5 cm) soils. Differences of up to 4 orders of magnitude were found between sites for PCBs. The lowest and highest PCB concentrations (26 and 97,000 pg/g dw) were found in samples from Greenland and mainland Europe (France, Germany, Poland), respectively. Background soil PCB concentrations were strongly influenced by proximity to source region and soil organic matter (SOM) content Most (>80%) of the estimated soil PCB burden remains in the "global source region" of the Northern Hemisphere (NH) temperate latitudes (30-60 degrees N) or in the OM-rich soils just north of that %SOM correlated with PCB and HCB in the global data set, with the correlation coefficients being greater for HCB and the lighter PCBs than for heavier homologues. OM-rich soils in the NH consistently contained the highest burdens; such soils are a key global compartment for these compounds. Evidence for global fractionation of PCBs was found in the subset of soils from latitudes north of the global source region but was not discerned with the global data set The full data set was used to estimate the burden for individual congeners/homologues in surface background soils and a global soil total PCB burden of 21,000 t. The significance of the inventory is briefly discussed in relation to the latest estimates of global production and atmospheric emission.
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