Effects of regional differences in waste composition on the thermal formation of polychlorinated aromatics during incineration

Two artificial wastes (A and B) whose contents reflect regional differences in municipal solid waste composition, were used to investigate the thermal formation of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and naphthalenes (PCNs) during incineration. Flue gas samples were simultaneously collected at three ports in the post-combustion zone corresponding to flue gas temperatures of 400, 300, and 200 °C. The combustion of Waste B, which had a higher chlorine and metal content than Waste A, produced greater levels of highly-chlorinated homologues, as demonstrated by a higher degree of chlorination. The total concentrations of PCDDs, PCDFs, PCBs, and PCNs formed in the combustion of both wastes increased as temperature decreased along the convector. There were no significant differences in total concentrations between Waste A and Waste B combustion at specific temperatures, with exception of PCDFs at 400 °C. Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) modeling, used to evaluate the data for all compound groups, suggest that during flue gas quenching at temperatures of 400 °C low-chlorinated homologues are preferentially formed in the presence of copper, which is known to be a very active catalyst for this process. At 300 and 200 °C, the formation of highly-chlorinated homologues is favored.     

Toxicological assessment of chlorinated diphenyl ethers in the rat

Abstract

Chlorinated diphenyl ethers are environmental contaminants that have been found in Great Lakes fish and birds. Because of their presence in the food chain, and potential for human exposure, the present short‐term study was conducted to assess their toxicity. Groups of 10 male and 10 female rats were each given by gavage 2,2’,4,4'6‐pentachlorodiphenyl ether (CDE1), 2,2’,4,4’,5,6‐hexachlorodiphenyl ether (CDE2) or 2,2’,3,3’,4,6'‐hexachlorodiphenyl ether (CDE3) at dose levels of 0.04, 0.4, 4.0 or 40 mg/kg b.w./day for a period of 28 days. The control group received an equivalent volume of corn oil only (0.5 ml/100 g b.w.). Treatment with the three CDE congeners did not result in suppression of growth rate or food consumption. Increased liver weights were seen in the animals of both sexes fed 40 mg/kg CDE2, in males treated with 40 mg/kg CDE1, and in females with 40 mg/kg CDE3. Hepatic microsomal aminopyrine demethylase activity was significantly higher in the male rats administered 40 mg/kg CDE2, and aniline hydroxylase activity was elevated in the females following the same treatment. Serum glucose, calcium, protein and urea nitrogen of CDE1‐treated males were higher than the control. Levels of uric acid, potassium and LDH of CDE3‐treated females were also elevated. No hematological changes were observed. Histological examination revealed that the liver and thyroid were the target organs affected by CDE treatment but the morphological changes were mild even at the highest dose level. Changes in the liver consisted of nuclear vesiculation and increased cytoplasmic volume. Alterations in the thyroid were characterized by increased epithelial height and follicular collapse. Based on the data presented above, the 3 CDE congeners can only be considered moderately toxic in the rat.     

多氯联苯光化学降解研究的最新进展

综述了近10年以来多氯联苯(PCBs)在有机相、表面活性剂中的直接光化学降解行为,以及PCBs在水相中的光敏化反应和光催化反应等间接光化学降解行为。从光解动力学、光解途径、光解机理以及光解产物等几方面阐述了PCBs的光化学行为,光催化降解有机污染物是一种很有发展前景的有机污染物治理技术。     

环境中多氯联苯（PCBs）的分析方法研究

探讨了环境中多氯联苯（PCBs）来源特性和分析检测方法。讨论了目前较为常用的样品前处理方法,如溶剂萃取法、固相萃取法、固相微萃取法等,常见的检测方法包括化学分析法和生物分析法,并对PCBs分析检测的发展前景进行了展望。     

秋冬季厦门岛大气颗粒物中PCBs的污染特征及入海通量

于2006至2008年秋季和冬季在台湾海峡西岸厦门岛采集大气颗粒物样品,分析28种多氯联苯（PCBs）,包括指示性PCBs和类二恶英PCBs的含量特征及组成,探讨其可能来源,并对其干沉降入海通量进行估算。结果显示,2006至2008年秋冬季厦门岛大气颗粒物中PCBs的浓度分别为0.43~53.55、2.07~81.14和3.79~153.39 pg/m³,主要以高氯取代PCBs为主,类二恶英PCBs毒性当量值与主要城市相当。冬季PCBs浓度高于秋季,且2006至2008年的秋冬季PCBs浓度呈上升趋势,这可能受到厦门市汽车尾气和工业废气排放等人类活动导致大气颗粒物含量升高的影响。气团后向轨迹分析表明,冬季厦门岛大气颗粒物中较高浓度的PCBs主要受中国北方大陆污染气团来源的影响,而秋季大多来源于洁净海洋气团。秋季和冬季,大气颗粒物中PCBs的沉降通量分别为3.79和8.32 ng/（m²·d）,按调查区域覆盖面积（63 000 km²）估算,通过大气干沉降向台湾海峡输入的PCBs量分别为22 kg和47 kg。     

Determination of PCBs, PCDDs and PCDFs in insulating oil samples from stored Chinese electrical capacitors by HRGC/HRMS

Homologue and congener profiles of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in commercial PCBs formulations are key information for the source identification of PCBs contamination as well as for the risk assessment caused by potential exposure. The isotope dilution technology in combination with high resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS) has made the accurate determination of such profiles possible. So far, various commercial PCB formulations except Chinese products have been successfully determined. Two PCBs containing insulating oil samples from stored Chinese electrical capacitors have been determined with the same methodology for comparability. The total concentration PCBs in two oil samples were 790 000 μg g⁻¹ and 720 000 μg g⁻¹, respectively. TriCBs, TetraCBs, and DiCBs were found to be most abundant. Concentration of dioxins contamination in two samples is 650-670 ngTEQ g⁻¹, of which 69-71 ngTEQ g⁻¹ from PCDD/Fs with the predominant congeners of 1,2,7,8-TeCDF; 2,3,7,8-TeCDF; 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDF. The contributions of DL-PCBs in total TEQ in both samples were more than 85%. The dioxin-like toxicity in insulating oils contained in electrical capacitors could be considered receive attention as an important dioxins source if such wastes are not managed in an environmentally sound manner.     

Prediction of environmental partition coefficients and the Henry's law constants for 135 congeners of chlorodibenzothiophene

Polychlorinated dibenzothiophenes (PCDTs) could be classified as persistent organic pollutants (POPs) in the environment and are particularly interesting due to their structural resemblance to highly toxic dioxins. We show here some basic environmental properties such as n-octanol water (K_OW), n-octanol/air (K_OA) and air/water (K_AW) partition coefficients as well as Henry’s law constants (K_H) for all 135 congeners of chlorodibenzothiophene. Predictions were made by regression of principal components (PCR) and with aid of a set of standard chemicals, for which physical–chemical properties are well featured. Computed K_OW, K_OA, K_AW and K_H values for mono-CDTs ranged, respectively, between 4.66 and 4.71, 7.48 and 7.55, −2.84 and −2.82, 3.56 and 3.74; for di-CDTs between 5.02 and 5.28, 8.03 and 8.29, −3.01 and −2.95, 2.42 and 2.75; for tri-CDTs between 5.53 and 5.70, 8.65 and 8.87, −3.2 and −3.11, 1.58 and 1.92; for tetra-CDTs between 5.95 and 6.13, 9.27 and 9.50, −3.39 and −3.27, 1.02 and 1.33; for penta-CDTs between 6.38 and 6.51, 9.88 and 10.05, −3.54 and −3.45, 0.72 and 0.88; for hexa-CDTs between 6.83 and 6.97, 10.54 and 10.66, −3.72 and −3.64, 0.47 and 0.56; for hepta-CDTs between 7.28 and 7.35, 11.12 and 11.20, −3.81 and −3.87, 0.33 and 0.38; for octa-CDT 7.74, 11.78, −4.04 and 0.23. An estimated value of the three types of partition coefficient and Henry’s law constants suggest that polychlorinated dibenzothiophenes are lipophilic and semi-volatile persistent organic pollutants. Their mobility in the environment seems to be very similar to that of some well-known POPs such as polychlorinated dibenzofurans, -dibenzo-p-dioxins, and -biphenyls or organochlorine pesticides.     

Airborne PCDD/Fs in two e-waste recycling regions after stricter environmental regulations

Since the 2010 s, the authorities of Guangdong province and local governments have enhanced law enforcement and environmental regulations to abolish open burning, acid washing, and other uncontrolled e-waste recycling activities. In this study, ambient air and indoor dust near different kinds of e-waste recycling processes were collected in Guiyu and Qingyuan to investigate the pollution status of particles and polychlorinated dibenzo-pdioxins and furans(PCDD/Fs) after stricter environmental regulations. PM_(2.5) and PCDD/Fs both showed significantly reduced levels in the two regions compared with the documented data. The congener distribution and principal component analysis results also confirmed the significant differences between the current PCDD/Fs pollution characterizations and the historical ones. The estimated total intake doses via air inhalation and dust ingestion of children in the recycling region of Guiyu ranged from 10 to 32 pg TEQ/(kg·day), which far exceeded the tolerable daily intake(TDI) limit(1–4 pg TEQ/(kg·day). Although the measurements showed a significant reduction of the release of PCDD/Fs, the pollution status was still considered severe in Guiyu town after stricter regulations were implemented.     

Revisiting old lessons from classic literature on persistent global pollutants: This article belongs to Ambio’s 50th Anniversary Collection. Theme: Environmental contaminants

Looking back 50 years at classic literature was a reminder of inspiring discoveries and clever theories that were formative to the field of environmental chemistry, but also of the irreparable costs that persistent global pollutants have had on ecosystems and human society. In my view, these three papers have greatly impacted contemporary science and influenced development of policies that have limited the spread of hazardous contaminants. At the same time, a sobering reality is that reversing decades of past pollution has proven impossible in our lifetime, and global trends are dire for both legacy and emerging contaminants. Lessons in these papers are clear to most environmental scientists, but I argue have not resulted in adequate investment in infrastructure or manpower to enable systematic unbiased searching for pollutants as proposed by Sören Jensen in 1972. Acknowledging that the costs of new global contaminants will be too high, we must incentivize safer chemicals and their sustainable use, increase international exchange of lists of chemicals in commerce, and coordinate international efforts in nontarget screening to identify new contaminants before they circulate the world.     

Fungal hydroxylation of polychlorinated naphthalenes with chlorine migration by wood rotting fungi

Biodegradation of the polychlorinated naphthalenes (PCNs) 1,4-dichloronaphthalene (1,4-DCN), 2,7-dichloronaphthalene (2,7-DCN), and 1,2,3,4-tetrachloronaphthalene (1,2,3,4-TCN), by the white-rot fungus Phlebia lindtneri was investigated. 1,4-DCN was metabolized to form six metabolites by the fungus. It was estimated from GC–MS fragment patterns that the metabolites were four putative hydroxylated and two dihydrodihydroxylated compounds. One of the hydroxylated products was identified as 2,4-dichloro-1-naphthol by GC–MS analysis using an authentic standard. This intermediate indicated chlorine migration in a biological system of P. lindtneri. 2,7-DCN was metabolized to five hydroxylated metabolites and a dihydrodihydroxylated metabolite. Significant inhibition of the degradation of DCNs and formation of their metabolic products was observed in incubation with the cytochrome P-450 monooxygenase inhibitor piperonyl butoxide. The formation of the dihydrodiol-like metabolites, chlorine migration and the experiment with P-450 inhibitor suggested that P. lindtneri provides hydroxyl metabolites via benzene oxide intermediates of DCNs by a cytochrome P450 monooxygenase. In addition, P. lindtneri degraded 1,2,3,4-TCN; two hydroxylated compounds and a dihydrodihydroxylated compound were formed.