Bleached pulp exposure

Methods for Determining Biomarkers of Exposure and Effect. Metabolites of chlorinated phenoloic compounds in fish bile have been found to be sensitive biomaikers of bleach pulp mill effluent exposure (Brumley et al. 1996). Analysis of metabolites of chlorinated syringaldehydyes in fish bile can provide a biomarker of effluent exposure that is sensitive to low levels of exposure and correlates well with exposure concentrations. No data are available on methods that determine biomarkers of exposure and effect in humans were located. Methods for determining biomarkers of exposure and effect in humans would be helpful. 

Sullivan MJ, Stanford JT. 1990. Risk associated with potential exposure to dioxin through consumption of tea brewed using tea bags containing bleached pulp. Chemosphere 20 1755-1762. 

BLEACHED pulp. The initial experiment was followed by similar exposures of handsheets prepared from a bleached pulp (BP). Again the UF-3-filtered situation resulted in a lesser development of HAS matter (Figure 2a). The initial photochemical and subsequent thermally-induced changes in HAS matter were less extensive than in the case of the unbleached pulp (2a and b). 

Figure 2. Development of hot-alkali-soluble matter and loss of degree of polymerization in bleached pulp during exposure to "daylight" fluorescent lamps and subsequent thermal aging.

Figure 6. Data on the direct exposure of filter paper (FP) and bleached pulp (BP) summarizing the results in terms of the percentage of links broken versus footcandle hours of exposure to "daylight" fluorescent lamps. Each set of symbols signifies a different experimental run the shaded data points refer to the present results shown in Figures 3 and 5.

Exposure of Bleached Pulp. Bleached pulp, based on 50% hardwood and 50% softwood kraft, jordaned to a Canadian standard freeness of 300-350 mL, was kindly supplied by Andrew Chase of the University of Maine. Unaged handsheets made from this pulp contained 85% a-cellulose (3) and 5% hot-1%-alkali-soluble matter (4). In the experiment illustrated in Figure 1, sheets were exposed in the Atlas 6500-W xenon-arc Fade-ometer equipped with Pyrex-glass filters the air temperature was 31 °C, and the relative humidity was 27% the black-panel temperature was 65 °C. Halfway through the reported period of... 

Figure 2. Change in 2/ DPV with time of exposure. Photochemical deterioration of bleached-pulp handsheets, both oxidized and SBH reduced, in...

Lethality of 2,3,7,8-TCDD to freshwater teleosts is documented at concentrations as low as 0.038 ng/L in water and 55.0ng/kg FW in sac fry (Table 14.2). It is noteworthy that water column concentrations of 2,3,7,8-TCDD immediately downstream of 89% of 104 chlorine-bleaching pulp and paper mills exceeded 0.038 ng/L. More research is needed on dietary routes of PCDD exposure to aquatic organisms. A simple apparatus for loading 2,3,7,8-TCDD and other chemicals onto commercially available pelletized fish food is now available. Recommended safe levels for aquatic life protection are 0.01 ng/L in water and 34.0ng4cg FW tissue, and these confer a degree of protection based on lethal action - of 1.6-3.8 times (Table 14.2). Values for 2,3,7,8-TCDD protection of freshwater aquatic life are in sharp contrast to those recommended for birds and mammals, which were usually... 

The vanadium-substituted polyoxometalates are applied to chemical pulps as stoichiometric oxidants, much as elemental chlorine is currently used. The reduced polyoxometalate bleaching solutions are regenerated in a second step by treatment with chlorine-free terminal oxidants, preferably air or dioxygen. By exclusion of dioxygen during the bleaching step, exposure of the pulp to non-selective species such as hydroxyl radicals is avoided entirely. 

Because pulp bleaching agents are, for the most part, reactive oxidising agents, appropriate precautions must be taken in their handling and use. For example, it is important to ensure that the threshold limit values (TLV) (20) in Table 2 are not exceeded in the workplace air. These are airborne concentrations in either parts per million by volume under standard ambient conditions or mg per cubic meter of air. They "represent conditions under which it is beUeved that nearly all workers may be repeatedly exposed, day after day, without adverse effect" (20). TWA refers to a time-weighted average for an 8-h workday STEL is a short-term exposure limit or maximum allowable concentration to which workers can be continuously exposed for 15 minutes. 

Brumley CM, Haritos VS, Ahokas JT, et al. 1996. Metabolites of chlorinated syringaldehydes in fish bile as biomarkers of exposure to bleached eucalypt pulp effluents. Ecotoxicol Environ Saf 33 253-260. 

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