PCDDs, PCDFs, dioxin-like PCBs and indicator PCBs in soil from five selected areas in Slovakia

There is a lack of information regarding persistent organic pollutants (POPs) in soil from Slovakia. This paper reports the concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), 12 dioxin-like polychlorinated biphenyls (dl-PCBs) and 6 indicator PCBs associated with 32 soil samples collected in 2007 from areas in the vicinity up to several kilometres from four selected industrial PCDD/F sources in Slovakia and one background area.The results show that the total WHO₁₉₉₈-PCDD/F/dl-PCB-TEQ concentrations varied from 0.34 to 18.05 pg g⁻¹ dry weight (dw) and the average total TEQ concentrations in samples collected at the Šala, Košice, Krompachy and Dubová areas were 3.18, 2.64, 7.80, and 3.19 pg g⁻¹ dw respectively. The average of the total WHO₁₉₉₈-TEQ values in three soil samples representing the background Starina area was 0.66 pg g⁻¹ dw. The predominant contaminants among 2,3,7,8-substituted PCDD/Fs, dl-PCB, and indicator PCBs was OCDD, PCB 118, and PCB 153 respectively. The major contributors to the TEQ were 2,3,4,7,8-PeCDF, PCB 126, 1,2,3,7,8-PeCDD, PCB 156 and 1,2,3,4,7,8-HxCDF + 1,2,3,4,7,9-HxCDF in descending order.     

Polychlorinated biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in surface sediments from Monastir Bay (Tunisia,Central Mediterranean): Occurrence,distribution and seasonal variations

An assessment of PCB and PBDE contamination of surface sediments in Monastir Bay was carried out in two contrasted seasons of the year. Samples were collected from 5 sites and analyzed for the ∑₇ marker PCBs (i.e. PCBs 28, 52, 101, 118, 138, 153 and 180) and ∑₄ PBDE congeners (PBDEs 47, 99, 119 and 153) by GC/ECD. Concentrations of both PCBs and PBDEs showed seasonal variations. PCB concentrations were in the range of 3.1–9.3 ng g⁻¹ and 1.1–8.1 ng g⁻¹ in wet and dry season respectively, and sediments were considered moderately contaminated with PCBs. All PCBs analyzed were detected in surface sediments. PCB 153 and 52 congeners showed the highest relative abundance in both winter and summer. PBDE concentrations ranged from not detect to 0.1 ng g⁻¹, with only BDE-47 congener detected in sediments and only in winter. Analysis of spatial and seasonal variations indicated that PCB distribution is governed by hydrodynamics and temporal variability of inputs. While the PCB contamination appeared to be mainly land-based, PBDEs are suspected to originate from atmospheric deposition.     

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。     

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.     

济南市道路尘中类二噁英类多氯联苯残留情况

通过采集济南市区主要路段道路尘样品,用气相色谱-电子俘获检测器(GC-ECD)方法分析了济南市区主要路段道路尘中毒性较高的12种类二噁英类多氯联苯(DL-PCBs)的残留情况,并对样品中DL-PCBs的含量、污染水平及同系物的组成进行了详细研究。结果发现,DL-PCBs在各采样点均有检出,残留总浓度在0.20～22.84ng/g(干重)范围内,平均值为0.0051ng/kg,同系物PCB81的检出率最高为90%,而同系物PCB189未被检出。计算的毒性当量(TEQ)值显示,对毒性当量贡献最大的是同系物PCB126,其TEQ值高达117.100pg/g(干重)。由平均残留百分含量较大的同系物结构分析可知,济南市区主要路段道路尘中非邻位氯取代的剧毒类二噁英类PCBs含量相对较大。