Mercury particulate fraction

In total mercury determinations, filtration of seawater samples has been found to be a serious source of contamination (see also Chapter 2). Hierefore, filtration should only be considered in cases where the suspended particulate matter (SPM) needs to be investigated separately and/or when the particulate fraction of Hgr is >20% and expected to fluctuate strongly as, e.g., in estuaries and other coastal zones. 

Research indicates that a significant fraction (50-90% ) of mercury is volatilized and lost during coal combustion (10, 11, 12) and that many of the potentially hazardous trace elements appear concentrated upon finer particulate emissions (13, 14). Several investigators have observed enrichment of these hazardous elements upon particulates in urban areas... 

In addition to this, another, often overlooked issue is the disposal of solid byproducts of the incineration process. MSW incinerators essentially produce two types of solid by-products. The first is the slag, or bottom ash, which is mostly made of the noncombustible fractions of the waste, plus a small fraction of the combustible fraction. The second is fly ash, the particulate material captured in the particulate removal section of the flue gas treatment plant, which is often mixed with various other chemicals used for flue gas treatment. Bottom ash and fly ash are characterized by very high concentrations of PTE, such as lead, mercury, cadmium, and nickel, which can easily leach into the environment. 

The presence of mercury in natural gas has been detected in numerous fields for many years. Mercury found in natural gas is generally in metallic form and its concentration varies from 1 to 75pgNm Natural gas associated condensates are very different First the mercury found in condensates is present in various chemical states elementary, ionic and organometallic second, arsenic is often simultaneously present third, the concentration ranges of mercury and arsenic are generally and, respectively, in the ranges of 10 to 3000 ppb and 10 to 150 ppb. The distribution of mercury and arsenic for an Asian condensate is shown in Fig. 18.30. For this particulate condensate, the large majority of mercury is found in the C3 and C fractions, whereas, arsenic was almost exclusively found in the residue. 

It has been well-documented that fossil fuel canbustion is a source of mercury contamination. The mercury content of thirty-six American coals ranged from about 70 ppb to as much as 33,000 ppb (Joensuu, 1971). Studies conducted by Gladney and Gordon (1978) indicate that as much as 93 percent of the total mercury liberated from a coal-fired power plant was concentrated in the < 2 pm particulate size fraction. Mercury data for oil is limited although crude oil samples from California contained frcmi 1,900 to 21,000 ppb mercury (Bailey, et al., 1961). 

Gold (Au), when administered to the rat as either NaAuCl4, or sodium aurothiomalate, accumulates in the particulate component of the kidney and in low molecular weight metalloprotein fraction of the cytosol. Induction of metallothionein synthesis by Au not only seems to be less efficient than that in response to mercury (Hg), cadmium (Cd) and bismuth (Bi) (PiOTROWSKi et al. 1979), but also to be determined by changes in copper distribution (Mo-GiLNiCKA and Webb 1981). Pre-treatment with Cd increased the contents of metallothionein-bound Au, Cu and Zn in the hamster kidney (Mogilnicka and Webb 1982). 

For the determination of particulate mercury, add-cleaned Teflon and quartz fibre filters, the latter combusted at 500 °C (Coquery and Cossa, 1995), are recommended. A significant fraction of the mercury in seawater is present in colloidal forms and separated with the aid of add-cleaned ultrafiltration cartridges (Stordal et oL, 19%). 

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