Stabilization of residues obtained from the treatment of laboratory waste: Part 2--transformation of plasma vitrified slag into composites

The Sustainable Environment Research Center of National Cheng Kung University in Taiwan has set up a treatment plant to dispose of laboratory waste. In the treatment process, the residue from the incineration system and the physical and chemical system is vitrified by a plasma melting system. Part 1 of this study described the treatment path of metals during vitrification. In Part 2, plasma vitrified slag is reused by using a molding technology. Unsaturated polyester resin and glass fiber were used as the molding material and additive, respectively, in the molding process. With an appropriate mixing ratio of unsaturated polyester resin, glass fiber, and slag, the physical properties of composites improved, and the ultimate tensile strength reached 17.6 MPa. However, an excess amount of slag reduced the strength and even retarded the production of composites. Differential thermal analysis and the water bathing test results show that the composite decomposed at 80 degrees C and that it vaporized at 187 degrees C. Although the unsaturated polyester resin decomposed, the metal encapsulated in the slag did not leach out. The results show that the reuse of slag using molding technology should be taken into consideration.     

Coating effects on the glass adsorption of polychlorinated biphenyl (PCB) congeners

The effects of coating materials on polychlorinated biphenyl (PCB) adsorption in aqueous solution were assessed in an attempt to minimize PCB sorption loss during sampling processes. A coating material, which enhances PCB adsorption and allows adsorbed PCBs to be readily extracted by solvents, can act as a sampling concentrator to reduce PCB losses from both adsorption and evaporation. Several coating materials were evaluated, including paraffin oil, silicone oil, dimethyldichlorosilane (Sylon-CT), Prosil 28^® and polydimethylsiloxane (PDS) with viscosity 0.65, 50 (PDS 50), and 500 (PDS 500) cSt. PDS and silicone oil enhanced adsorption for all five congeners examined (IUPAC No. 28, 52, 101, 138, and 180). Sylon-CT, paraffin oil and Prosil 28^® had inconsistent effects on adsorption of different congeners. Desorption of adsorbed PCBs onto all coating types was assessed. The recovery efficiency of extracting PCBs with solvents was enhanced greatly with all coatings as opposed to non-coated surfaces, with the exception of paraffin oil. Coating with silicon oil, PDS 50, and 500 resulted in virtually 100% recovery of adsorbed PCBs. It was also found that Teflon containers were poor substitutes for glass containers and failed to minimize PCB losses. Among the materials studied, the best coating that could be used as a sampling concentrator was PDS 500.     

Identification of a novel PCB source through analysis of 209 PCB congeners by US EPA modified method 1668

PCDD/Fs and PCBs in surface waters and effluent waste streams flowing into New York/New Jersey Harbor were sampled by large volume filtration and solid phase extraction (XAD-2). Passive hexane samplers were employed in sewer trackdown. Extraction media were analyzed for 2,3,7,8 substituted PCDD/Fs and all 209 PCB congeners. The non-Aroclor PCB congener, 3,3^′-DiCB, was ubiquitous in the harbor and was found to be associated with pigment manufacture. Knowledge of inadvertent synthesis of non-Aroclor PCBs is not new but its magnitude and the generation of congeners with dioxin-like properties from this process is novel.     

Congener-specific approach to human PCB concentrations by serum analysis

The objective of this study was to evaluate all congeners of polychlorinated biphenyls (PCBs) in human serum samples. Concentrations of all PCB congeners in the serum of 87 volunteers were determined by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The participants consisted of 47 males and 40 females, including 25 men working at municipal solid waste incinerators (MSWIs). The mean concentrations of total PCBs and dioxin-like PCBs were 242.77ng/g lipid (median: 180.17ng/g lipid) and 18.57ng/g lipid (median: 15.34ng/g lipid), respectively. Penta-, hexa-, and heptachlorinated biphenyls contributed more than 80% of the total PCBs detected in human serum. Congener-specific analysis indicated that PCB153, PCB138, PCB180, PCB187, and PCB118 contributed 57.3% of the total PCBs detected in human serum samples. A statistical analysis was performed to determine whether there were significant correlations between PCB concentrations and specific variables such as age, gender, smoking habits, occupation, and body mass index (BMI). However, serum PCB concentrations correlated only with age. In addition, we found that total PCBs and dioxin-like PCBs highly correlated with PCB153 (correlation coefficient r=0.93, p<0.01) and PCB118 (correlation coefficient r=0.98, p<0.01), respectively. Thus these two congeners could be satisfactory indicators for total PCBs and dioxin-like PCBs in human serum.     

Estimation of the contribution of a municipal waste incinerator to the overall emission and human intake of PCBs in Wilrijk, Flanders

The contribution of the emission of PCBs by a municipal waste incinerator in Wilrijk, a relatively industrialized district in the largest city of Flanders, to the total emission to air and to the total human intake was estimated. Therefore it was compared to the emission of PCBs by evaporation from PCB containing applications (transformers, capacitors, paint, ink, etc.) and to the intake of PCBs with food. As there was a lack of PCB data from the incinerator, the PCB emission concentration was estimated using three different approaches. A PCB measurement of the incinerator emission, performed later on, fell within the predicted range of 0.0004-0.005 ng TEQ/Nm3. Emission of PCBs from PCB containing applications and intake from food were deduced from information available on Flemish and European level. The results indicate a PCB contribution from the incinerator to local emissions between 0.3% and 3% of the emission from PCB containing applications and a contribution to human intake less than 6 x 10(-4)% of the intake from food.     

Review of PCBs in US schools: a brief history,an estimate of the number of impacted schools,and an approach for evaluating indoor air samples

PCBs in building materials such as caulks and sealants are a largely unrecognized source of contamination in the building environment. Schools are of particular interest, as the period of extensive school construction (about 1950 to 1980) coincides with the time of greatest use of PCBs as plasticizers in building materials. In the USA, we estimate that the number of schools with PCB in building caulk ranges from 12,960 to 25,920 based upon the number of schools built in the time of PCB use and the proportion of buildings found to contain PCB caulk and sealants. Field and laboratory studies have demonstrated that PCBs from both interior and exterior caulking can be the source of elevated PCB air concentrations in these buildings, at levels that exceed health-based PCB exposure guidelines for building occupants. Air sampling in buildings containing PCB caulk has shown that the airborne PCB concentrations can be highly variable, even in repeat samples collected within a room. Sampling and data analysis strategies that recognize this variability can provide the basis for informed decision making about compliance with health-based exposure limits, even in cases where small numbers of samples are taken. The health risks posed by PCB exposures, particularly among children, mandate precautionary approaches to managing PCBs in building materials.     

废旧冰箱拆解聚氨酯泡沫塑料制备PU/PP复合材料

利用废旧冰箱拆解的聚氨酯泡沫塑料(PU)和聚丙烯(PP)、聚丙烯接枝马来酸酐(PP-g-MAH)为原料,采用物理化学回收技术制备PU/PP复合材料。用正交实验法分析PU填充量、PU粒径和PP-g-MAH 3个因素对PU/PP复合材料力学性能影响的显著性。结果表明,PU填充量对PU/PP复合材料拉伸性能有显著影响,对冲击性能和弯曲性能没有显著影响;在本文的实验范围内,PU粒径对PU/PP复合材料的力学性能影响不大;而PP-g-MAH投加量对PU/PP复合材料具有一定的影响。确定的优化工艺配方为:PU 40%;PU粒径选择2.00 mm;PP-g-MAH投加量10%。采用优化工艺制备的PU/PP复合材料的密度为1 042.88 kg/m3;冲击强度为2.9 kJ/m2;拉伸强度为10.30 MPa;拉伸模量为1 100 MPa;弯曲强度为18.5 MPa;弯曲模量为733 MPa。     

Update on Building and Structure Decontamination

Cleanup of the nation’s hazardous waste sites is a top environmental priority. Since the ultimate objective of many cleanup programs is to return the contaminated site and buildings on the site to active use, additional information regarding both established and emerging technologies for building decontamination is needed.

A pilot scale study was performed at an actual Superfund Site to evaluate, side by side, the efficacy of PCB removal using two decontamination processes. One process entails use of a shotblasting technique in which contaminated concrete surfaces are cut away and physically removed. The other process involves application of an alkali metal/polyethylene glycolate mixture directly to contaminated concrete surfaces for insitu degradation of PCBs.     

Evaluation of PCB sources and releases for identifying priorities to reduce PCBs in Washington State (USA)

Polychlorinated biphenyls (PCBs) are ubiquitously distributed in the environment and produce multiple adverse effects in humans and wildlife. As a result, the purpose of our study was to characterize PCB sources in anthropogenic materials and releases to the environment in Washington State (USA) in order to formulate recommendations to reduce PCB exposures. Methods included review of relevant publications (e.g., open literature, industry studies and reports, federal and state government databases), scaling of PCB sources from national or county estimates to state estimates, and communication with industry associations and private and public utilities. Recognizing high associated uncertainty due to incomplete data, we strived to provide central tendency estimates for PCB sources. In terms of mass (high to low), PCB sources include lamp ballasts, caulk, small capacitors, large capacitors, and transformers. For perspective, these sources (200,000–500,000 kg) overwhelm PCBs estimated to reside in the Puget Sound ecosystem (1500 kg). Annual releases of PCBs to the environment (high to low) are attributed to lamp ballasts (400–1500 kg), inadvertent generation by industrial processes (900 kg), caulk (160 kg), small capacitors (3–150 kg), large capacitors (10–80 kg), pigments and dyes (0.02–31 kg), and transformers (<2 kg). Recommendations to characterize the extent of PCB distribution and decrease exposures include assessment of PCBs in buildings (e.g., schools) and replacement of these materials, development of Best Management Practices (BMPs) to contain PCBs, reduction of inadvertent generation of PCBs in consumer products, expansion of environmental monitoring and public education, and research to identify specific PCB congener profiles in human tissues.     

Bioaccumulation of polychlorinated biphenyls in ranid frogs and northern water snakes from a hazardous waste site and a contaminated watershed

Livers of bullfrogs (Rana catesbeiana) from a polychlorinated biphenyl (PCB) contaminated watershed and hazardous waste site located in Pickens County, South Carolina, contained significantly higher concentrations of PCBs (2.33 and 2.26 ppm, respectively) than those from a reference site (0.05 ppm). Green frogs (R. clamitans) from the two contaminated sites also accumulated higher levels of PCBs (2.37 and 3.88 ppm, respectively) than those from the reference site (0.02 ppm). No temporal variation was observed in PCB concentrations of bullfrogs or green frogs from the contaminated sites between 1992 and 1993. Levels of PCBs in the livers of northern water snakes (Nerodia sipedon) were significantly higher in snakes from the contaminated watershed (13.70 ppm) than in those from the waste site (2.29 ppm) and two reference sites (2.50 and 1.23 ppm). When compared to frogs, significantly higher bioaccumulation occurred in water snakes from the contaminated watershed. No significant differences in PCB levels were found with respect to sex or body size (snout-vent length (SVL) or body mass) for frogs or snakes. PCBs were detected also in eggs of both frogs and snakes. Results of this study provide baseline data and document the bioaccumulation of PCB residues in frog and snake tissues; however, the significance of these tissue residues to reproduction, survival, growth/development, and population dynamics in contaminated habitats is unknown.     

Evaluation of cumulative PCB exposure estimated by a job exposure matrix versus PCB serum concentrations

Although polychlorinated biphenyls (PCBs) have been banned in many countries for more than three decades, exposures to PCBs continue to be of concern due to their long half-lives and carcinogenic effects. In National Institute for Occupational Safety and Health studies, we are using semiquantitative plant-specific job exposure matrices (JEMs) to estimate historical PCB exposures for workers (n?=?24,865) exposed to PCBs from 1938 to 1978 at three capacitor manufacturing plants. A subcohort of these workers (n?=?410) employed in two of these plants had serum PCB concentrations measured at up to four times between 1976 and 1989. Our objectives were to evaluate the strength of association between an individual worker’s measured serum PCB levels and the same worker’s cumulative exposure estimated through 1977 with the (1) JEM and (2) duration of employment, and to calculate the explained variance the JEM provides for serum PCB levels using (3) simple linear regression. Consistent strong and statistically significant associations were observed between the cumulative exposures estimated with the JEM and serum PCB concentrations for all years. The strength of association between duration of employment and serum PCBs was good for highly chlorinated (Aroclor 1254/HPCB) but not less chlorinated (Aroclor 1242/LPCB) PCBs. In the simple regression models, cumulative occupational exposure estimated using the JEMs explained 14–24 % of the variance of the Aroclor 1242/LPCB and 22–39 % for Aroclor 1254/HPCB serum concentrations. We regard the cumulative exposure estimated with the JEM as a better estimate of PCB body burdens than serum concentrations quantified as Aroclor 1242/LPCB and Aroclor 1254/HPCB.     

A case of polychlorinated biphenyl contamination of water and sediment in the Slovenian karst region (Yugoslavia)

An incident is described in which polychlorinated biphenyls (PCBs) from an electro-industrial plant waste tip draining into ground-water channels in karst terrain have contaminated a potable water source. PCB composition data were obtained using quadropole GC-MS and capillary GC. The average level of PCBs determined in water was 0.3 μg 1^?1 and in sediment 55 μg g^?1     

PCB removal from contaminated dredged material

The purpose of this study was to evaluate the feasibility of decontaminating PCB contaminated sediment using land treatment technology. Five glass aquariums were set up to test the disappearance of polychlorinated biphenyls (PCBs) in dredged sediment under laboratory conditions that simulated photodegradation, biological transformation, and volatilization in dredged material confined disposal facilities (CDFs). A 40% decline in PCB concentration was achieved over a period of 5 months. Analysis of the variance in the data showed that periodic tilling produced a tangible effect on the disappearance of PCBs. However, the process or processes responsible for PCB disappearance could not be determined. PCB disappearance from the sediment was most likely caused by a combination of photolysis, volatilization, and biodegradation mechanisms rather than by any single process.     

PCBs contributions to the total TEQ released from Korean municipal and industrial waste incinerators

Non-ortho and mono-ortho polychlorinated biphenyls (PCBs) were determined in the stack gases and the fly-ash from nine Korean municipal solid waste incinerators (MSWIs). Soil samples collected near MSWI and industrial waste incinerator (IWI) sites were also examined for PCBs. The PCBs levels in the stack gas samples ranged between 0.0046 and 12.0 TEQ-ng/Nm³. The PCB homologue profiles were distinct for the stack gas samples and different from the fly-ash. PCBs levels in soil samples collected near MSWIs and IWI ranged between 0.86 and 19.73 TEQ-ng/g with background levels of 0.17 TEQ-ng/g. The lower chlorination PCBs were dominant in the soil samples. The stack emission PCBs homologue patterns were compared to those detected in the soil samples. The findings suggest that localized point sources as well air mass movement contribute to the deposition of PCBs onto soil.     

酸化油渣与膨胀型阻燃剂协效阻燃环氧树脂

餐厨垃圾生产柴油中产生酸化油渣固废(AR)。采用红外光谱(FTIR)法对AR进行分析,认为AR具有较好的阻燃成炭性能。将AR与多聚磷酸铵/三聚氰胺/季戊四醇(APP/MEL/PER)膨胀阻燃体系(IFR)复配,协效阻燃环氧树脂(EP),用极限氧指数法(LOI)、垂直燃烧法(UL94)对其阻燃性能进行了检测,并通过对燃烧残渣的分析讨论了阻燃机理。结果表明,当APP/MEL/PER/AR质量分数为25%,其中AR的质量分数为2%~6%时,阻燃EP的LOI达到30%,具有良好的阻燃性能,并降低了阻燃剂及阻燃材料总体成本。研究成果对餐厨垃圾能源化起到积极推动作用。     

Analysis of PCBs in sediments by glass capillary gas chromatography

The analysis of individual PCB components in river sediments with glass capillary gas chromatography was studied. For Aroclor 1242 a mean recovery of over 85 % was established. Decachlorobiphenyl contents obtained by perchlorination appear to be 1.1 to 3.7 times higher than total-PCB contents estimated with capillary GC. Besides reliable contents of individual PCBs the capillary method provides information about the composition of the PCB contamination in sediments and may be of use in the identification of PCB sources.     

Congener-specific egg contribution of polychlorinated biphenyls to nestlings in two passerine species

Quantifying polychlorinated biphenyl (PCB) residues in nestlings of avian species is a common method for assessing trophic transfer and risk at PCB-contaminated sites. The proportion of nestling PCB mass due to maternal transfer is often accounted for by subtracting total PCB mass in eggs from nestlings. However, variation in physicochemical properties and metabolism among congeners may lead to differences between egg contribution based on total PCBs and dioxin-like congeners. We examined congener-specific variation in contribution of PCBs from eggs to nestlings in tree swallows and European starlings. Egg contribution of total PCB mass was 14.3 and 16.2%, respectively, whereas contribution based on dioxin-like congeners was 14.8 and 13.6%, respectively. These data suggest that using total PCB mass in eggs to adjust estimates of PCB accumulation in nestlings may not reflect patterns for dioxin-like congeners, potentially over or under-estimating the risk of toxicity of PCBs.     

Polychlorinated dibenzo-p-dioxins, dibenzofurans and 'dioxin-like' PCBs in flue gas emissions from municipal waste management plants

The aim of this work is to give representative data on polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyl (PCBs) from stack gas emissions of an urban solid waste management plant which has to comply with the limit of 0.1 ng I-TEQ/Nm3. In particular, the study is focused on 29 target compounds, the seventeen 2,3,7,8-PCDDs/Fs, four non-ortho PCBs and eight mono-ortho PCBs which configure so-called 'dioxin-like' PCBs (DL-PCBs). To this end, emission measurements were performed during one year over the three operating combustion lines in a selected waste management plant. In general, accurate methodology allowed characterizing all target compounds in almost all the samples analyzed. In addition, a typical pattern for DL-PCBs is reported. The pattern presented PCB #118 to be the highest, nevertheless the figures demonstrated DL-PCBs contribution to the total TEQ around 3% being PCB #126 the most important congener due to its TEF of 0.1. Finally, remarkable differences were achieved in comparison with both environmental and biological samples such as soils, sediments, human milk or fish since these matrices may present DL-PCB contribution to the total TEQ up to 77%.     

PCBs and PCDD/Fs in lake sediments of Grosser Arbersee, Bavarian Forest, South Germany

Despite their environmental importance, there are still relatively few historical studies of the environmental occurrence of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), especially in middle Europe. Trends in PCBs and PCDD/Fs were, therefore, assessed in lake sediments of the Grosser Arbersee over the past 130 years (1860-1990). Ballschmiter-PCB concentrations (congeners # 28, 52, 101, 138, 153, 180) increased between 1946 and 1972 from 4.2 to 32.0 microg kg(-1) dry wt, but have since decreased to 25.6 microg kg(-1) dry wt. High chlorinated PCB congeners reached their maxima earlier (1968-1972) than low chlorinated congeners (1985-1991). These trends were consistent with patterns expected from the production and use of PCBs and their precursors. PCDD/F concentrations increased between 1950 from 0.6 microg kg(-1) dry wt to 2.3 microg kg(-1) dry wt in 1977, falling to 1.7 microg kg(-1) dry wt by 1993. PCDF concentrations exceeded those of PCDD until 1968, but afterwards PCDDs (especially OCDD) were predominant. These patterns suggest that domestic heating and waste combustion were the most likely sources, but pollution from local industries, such as metal smelting and glass production, might also have been involved. The data provide a valuable case study from central Europe which confirms the overall declining trends of PCB and PCDD/F contamination shown elsewhere.     

Polychlorinated Biphenyl Recovery Efficiency from Stack Gas and Ambient Air

Polychlorinated biphenyls (PCBs) are now recognized as presenting a severe environmental hazard because of their toxicity and persistence in the environment. High temperature combustion has been shown to be an effective method for destroying these compounds.¹ Unfortunately, few facilities are available for their destruction. As part of a feasibility study to convert a liquid-waste incinerator designed for waste fuel to a PCB waste, the sampling efficiency of toluene filled fritted impingers and Chromosorb 102 filled tubes was evaluated.