Occurrence of and risk posed by highly carcinogenic dibenzo[def,p]chrysene isomers in urban soil

Dibenzopyrene and its isomers are considered the most potent carcinogens of all polycyclic aromatic hydrocarbons tested to date. However, despite public concerns over their deleterious effects, they have not been extensively studied. The occurrence of four highly carcinogenic isomers of dibenzopyrene – dibenzo[def,p]chrysene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene in urban soil samples from Shanghai, China, have been determined in this study, as well as that of benzo[a]pyrene and coronene. A total of 14 peaks with ions at m/z 302 were detected by gas chromatography-mass spectrometry. Although the concentrations of benzo[a]pyrene and the sum of the 16 priority polycyclic aromatic hydrocarbons were greater than that of dibenzopyrene and its isomers, the carcinogenic potency of the latter was higher than that of benzo[a]pyrene. The results also indicate that the relative carcinogenic potency of the four dibenzopyrene isomers in the samples is higher than that of the 16 priority polycyclic aromatic hydrocarbons.     

Removal of bisphenol A from wastewater by physical,chemical and biological remediation techniques. A review

Environmental Chemistry Letters - Bisphenol A is a well-known endocrine-disrupting compound that is commonly detected in industrial effluents and wastewater treatment plants. It is extensively used...     

珠江八大入海口表层沉积物中DDTs和HCHs残留调查

于2010年8月-2011年5月4次采集珠江八大人海口表层沉积物,采用气相色谱-电子捕获（GC—ECD）法分析沉积物中DDTs（p,P’-DDE、P,P’-DDD、0,P’-DDT、P,P-DDT）和HCHs（α-HCH、β-HCH、γ-HCH、δ-HCH）的污染现状。结果显示,珠江8大人海口表层沉积物中DDTs总含量介于1．02—3．08μg·kg-1之间（以干质量计,下同）,平均值为1．91μg·kg-1;HCHs总含量介于0．21—0．41μg·kg-1之间,平均值为0．31μg·kg-1。DDTs平均含量大于HCHs,其中P,P。DDT对污染的贡献最大,含量范围为ND～7．66μg·kg-1,平均值为2．12μg·kg-1。大部分样点伽（α-HCH）／w（γ-HCH）比值小于3,说明研究区α-HCH大都被降解,或者林丹正取代工业HCHs成为珠江口水环境中HCHs输入的主要来源;甜（DDT）／w（DDD＋DDE）比值大于2,表明沉积物中除早期农药残留外,仍然有新的DDTs类农药输入。     

新农药氯虫酰胺在醇液中的光解

分别以氙灯和紫外灯为光源,对氯虫酰胺在甲醇和乙醇中的光解动力学及降解机理进行了研究。结果表明,在氙灯和紫外照射下,氯虫酰胺在甲醇和乙醇中的光解符合一级反应动力学规律。在模拟太阳光氙灯辐射下,氯虫酰胺在甲醇和乙醇中的光解半衰期分别为1．58h和2．57h,而紫外光辐射下分别为1．49min和1．60min。采用LC-MS对氯虫酰胺光解产物进行分离和鉴定,推断氯虫酰胺在醇中的光解途径主要涉及到分子环合和重排生成光解产物A[2-（2-溴-4H-吡唑并[1,5．d]吡啶并[3,2-b]B,4]恶嗪-4-基亚氨基）-5-氯-N,3-二甲基苯甲酰胺]和B[2-（3-溴-1-（3-羟基吡啶-2-基）-1H-吡唑-5-基）-6-氯-3,8-二甲基喹啉-4（3H）-酮1。     

Effects of the level of dietary protein on the toxicity of hexachlorocyclohexane in rats

Male albino rats were fed for 28 days from weaning on diets containing 5% (group 1), 10% (group 2) and 21% (group 3, normal protein) protein as casein. At the end of dietary period, HCH was administered daily for 30 days to investigate the interaction between protein deficiency and pesticide toxicity. The results indicated that rats fed a lower protein diet and HCH had a higher mortality, lower rate of growth, increased liver weight and deposition of the pesticide in blood and tissues in larger amounts. Blood pressure (systolic and diastolic) was significantly increased and the heart rate showed tachycardia in low protein exposed animals. A significant increase of total lipids, cholesterol, triglycirides, free fatty acids in serum and tissues of animals exposed to low protein was observed. A close correlation existed between lipid accumulation and storage of HCH in tissues and dietary protein seemed to play an important role in detoxification.     

连云港潮滩表层沉积物中有机氯农药残留特征与风险评估

利用GC-ECD检测了连云港地区绣针河口、临洪河口、灌河口北和灌河口南等4个潮滩断面表层沉积物中DDTs和HCHs含量及组成成分.结果表明,连云港潮滩沉积物中有机氯农药的含量在2.15—24.84 ng.g-1之间,均值为9.09 ng.g-1.其中DDTs的含量在1.11—11.74 ng.g-1之间,均值为3.72 ng.g-1,HCHs的含量在0.38—20.17 ng.g-1之间,均值为5.36 ng.g-1.4个断面有机氯农药含量的顺序是临洪河口>绣针河口>灌河口北>灌河口南.连云港潮滩沉积物中HCHs主要来源于早期林丹在土壤中的残留,灌河口有新的DDT污染源输入.总有机碳是影响绣针河口和临洪河口潮滩有机氯农药分布的主要因素.以风险低值(ERL)为评价基准,沉积物中有机氯农药的最大风险商达到7.43,连云港潮滩有机氯农药存在着一定的潜在生态风险.     

Ecological and health risks of DDTs and HCHs in surface water from the upper reaches of the Huaihe River

Based on the available toxicity data and the concentrations of DDTs and HCHs in surface water from the upper reaches of the Huaihe River, overlapping areas of probability density and margin of safety (MOS₁₀) were used to estimate the risk levels of DDTs and HCHs to aquatic organisms. The overlapping areas of α-HCH, γ-HCH, p,p′-DDE, p,p′-DDD, and p,p′-DDT were found to be 9.3 × 10^?5, 4.6 × 10^?3, 4.3 × 10^?2, 2.2 × 10^?2, and 4.2 × 10^?2, respectively. The risks from DDTs were higher than those from HCHs, the risk from α-HCH being the smallest. The MOS₁₀ values of α-HCH, γ-HCH, p,p′-DDE, p,p′-DDD, and p,p′-DDT were 2.6 × 10³, 97, 5.9, 15, and 8.6, respectively, i.e. greater than 1.0, indicating limited overlaps between the distributions of exposure concentrations and of toxicity data, and thus minimal ecological risk. Health risk calculations based on incremental lifetime risks for HCHs and DDTs were conducted to evaluate human cancer risk and non-carcinogenic hazard. The total cancer risks from organochlorine pesticides (OCPs) in the studied area were in the range of 10^?8–10^?7, lower than the baseline value of acceptable risk (10^?6). Non-carcinogenic hazard indices of OCPs ranging from 10^?6 to 10^?5 were much lower than the threshold values (1.0). These results suggest that the water from the upper reaches of the Huaihe River does not pose any health risk for local residents using river water as a source for drinking water.     

Photocatalytic degradation of ciprofloxacin in aqueous media: a short review

The frequent detection of antibiotics such as ciprofloxacin in surface and drinking waters around the world has attracted concern from various researchers. Such presence is an indication that the decontamination of water polluted by antibiotics is beyond the conventional treatment methods. However, among the different treatment methods that have been developed in the area of water purification, heterogeneous photocatalysis using semiconductor as a mediator has been rated as an efficient and a green wastewater treatment method. This is because, the process is effective in degrading and mineralizing organic pollutants, using UV or visible light. The present review paper covers a brief survey over a range of publications in the last decade, involving photocatalytic materials that have been employed in the purification of water contaminated by ciprofloxacin.     

A biological approach in the treatment of TNT wastewater

A mixed microbial population in digested sewage culture under strict anaerobic conditions degraded TNT (2,4,6‐trinitrotoluene) effectively. An initial concentration of 110 mg/L of TNT was reduced to a non‐detectable amount (> 99% removal) in 6 days of incubation. Red color due to the electron charge of NO₂ groups becomes colorless after 6 days of incubation, while the autoclave control remained red in color. Further stepwise deamination and subsequent mineralization by ring cleavage occurred by mixed nitroreductase which is available from many of the denitrifying bacteria predominantly in sewage culture.     

A new photoproduct of the drug furosemide in aqueous media

The solar phototransformation of furosemide has been investigated in aqueous media. Irradiation of the drug in distilled water, in water and humic acids or nitrate ions, and in sewage sludge water affords a new dehalogenated dimer. The formation of the dimer has been explained by the formation of a cation radical intermediate. The low-measured environmental concentration of furosemide with respect to predicted environmental concentration in the Po and Lambro Rivers could be justified by its phototransformation.     

Quorum sensing regulation methods and their effects on biofilm in biological waste treatment systems: A review

• Quorum sensing enhancement and inhibition methods are summarized. • Effects of quorum sensing regulation on biofilm are reviewed. • Current knowledge gaps and research challenges are proposed. Quorum sensing (QS) plays an important role in microbial aggregation control. Recently, the optimization of biological waste treatment systems by QS regulation gained an increasing attention. The effects of QS regulation on treatment performances and biofilm were frequently investigated. To understand the state of art of QS regulation, this review summarizes the methods of QS enhancement and QS inhibition in biological waste treatment systems. Typical QS enhancement methods include adding exogenous QS molecules, adding QS accelerants and cultivating QS bacteria, while typical QS inhibition methods include additions of quorum quenching (QQ) bacteria, QS-degrading enzymes, QS-degrading oxidants, and QS inhibitors. The specific improvements after applying these QS regulation methods in different treatment systems are concluded. In addition, the effects of QS regulation methods on biofilm in biological waste treatment systems are reviewed in terms of biofilm formation, extracellular polymeric substances production, microbial viability, and microbial community. In the end, the knowledge gaps in current researches are analyzed, and the requirements for future study are suggested.     

Ionic liquids for the inhibition of gas hydrates. A review

The formation of gas hydrates is a major issue during the operation of oil and gas pipelines, because gas hydrates cause plugging, thereby disrupting the normal oil and gas flows. A solution is to inject gas hydrate inhibitors such as ionic liquids. Contrary to classical inhibitors, ionic liquids act both as thermodynamic inhibitors and hydrate inhibitors, and as anti-agglomerates. Imidazolium-based ionic liquids have been found efficient for the inhibition of CO₂ and CH₄ hydrates. For CO₂ gas hydrates, N-ethyl-N-methylmorpholinium bromide showed an average depression temperature of 1.72 K at 10 wt% concentration. The induction time of 1-ethyl-3-methyl imidazolium bromide is 36.3 h for CO₂ hydrates at 1 wt% concentration. For CH₄ hydrates, 1-ethyl-3-methyl-imidazolium chloride showed average depression temperature of 4.80 K at 40 wt%. For mixed gas hydrates of CO₂ and CH₄, only quaternary ammonium salts have been studied. Tetramethyl ammonium hydroxide shifted the hydrate liquid vapour equilibrium to 1.56 K at 10 wt%, while tetrabutylammonium hydroxide showed an induction time of 0.74 h at 1 wt% concentration.

     

The neuston of the subtropical and boreal North-eastern Atlantic Ocean. A review

The present paper compiles results of recent studies on distribution, abundance, migratory pattern and feeding of invertebrates and early stages of fish in the uppermost layer of the subtropical and boreal Atlantic Ocean. Three ecological groups are described: euneuston, living permanently at the surface; facultative neuston, invading the uppermost layer mainly during night; pseudoneuston, comprising the uppermost part of populations which are mainly concentrated in deeper layers. For several species of fish, a shift in behaviour was found: eggs and yolk-sac larvae are mainly missing from the uppermost layers, young post-larvae staying permanently close to the surface, and old larvae and juveniles performing diurnal vertical migrations. During daytime, the uppermost layer serves as a refuge for only a small number of welladapted organisms, while at dusk and at night considerable immigration occurs. During daytime, zooneuston is mainly carnivorous or omnivorous. In boreal and turbid waters, the ecological differences between the uppermost and lower layers are reduced. Neuston is an important element of the ecosystem in these areas.     

Biotreatment strategies for the removal of microplastics from freshwater systems. A review

Environmental Chemistry Letters - Research on plastic pollution has recently evidenced the ubiquitous presence of tiny plastic particles called microplastics. Microplastics alter organisms because...     

A review of marine pollution issues in the Caribbean

Marine pollution and coastal degradation have become serious development issues in the Caribbean. Early evidence of marine pollution was mainly anecdotal, but within the last 10--15 years, work conducted by universities and research institutions in the Region has provided the beginnings of a database that identifies several common marine pollution problems. The United Nations Environment Programme (UNEP), the Intergovernmental Oceanographic Commission (IOC) and the Pan American World Health Organization (PAHO/WHO) have also been instrumental in co-ordinating several marine pollution studies. In the English-speaking Caribbean, the University of the West Indies, the Institute of Marine Affairs in Trinidad and Tobago, and the Caribbean Environmental Health Institute located in St Lucia, have taken a lead role in identifying marine pollution problems in their Sub-Region. For the Wider Caribbean a database for petroleum pollution and marine debris has been developed. Land-based sources of marine pollution have been identified as a major problem, with several hot spots identified in mainland countries and in some of the larger industrialised islands. Organic and nutrient pollution, particularly from sewage, is most widespread and is possibly the most serious marine pollution problem in the Caribbean. A lack of capital investment funds to install the appropriate infrastructure to deal with sewage and other liquid effluents is a major stumbling block to solving the problem of marine pollution in the Caribbean. Other factors include political will and administrative and legal structures to regulate human development activities.     

A review of arsenicals in biology

The most toxic form of arsenic is arsine gas. Arsenite is also highly toxic and arsenate is moderately toxic. Arsine gas will lyse red blood cells, arsenite inactivates particular enzymes and arsenate uncouples oxidative phosphorylation. Arsenic does not appear to be a significant mutagen. Epidemiological studies have implicated arsenic as a cause of lung cancer and skin cancer, but arsenic generally does not induce cancer in laboratory animals. Arsenic may bioaccumulate in some plants and marine organisms. Bacteria can be resistant to arsenic by preventing arsenate from entering the cell (chromosomal resistance) or pumping arsenic out of the cell (plasmid resistance). Many different organisms, including mammals, have the ability to methylate inorganic arsenic. Biomethylation seems to be a mechanism of arsenic detoxification.     

Combined technologies for the remediation of soils contaminated by organic pollutants. A review

Organic-contaminated soils are a major health issue because pollutants can be transferred to waters, air, and living organisms. Many remediation technologies have been developed, yet single methods are usually not fully efficient due to the wide diversity of soil and pollutant properties. Therefore, combining several methods has recently shown wider application range, higher efficiency, and better economic benefits. Here we compare combined remediation technologies to clean organic-contaminated soils, with focus on physical–chemical, physical–chemical-biological, and biological-microbial methods. Physical–chemical methods are the most widely used due to their high efficiency, yet they are costly, and they alter soil properties. These issues can be alleviated by adding a biological treatment. Combined biological-microbial methods are more recent and rely on bioengineering.

     

湿地碳循环研究综述

湿地由于其巨大的碳库储存能力而成为碳循环研究的热点之一.从湿地CO_2/CH_4释放时空格局,CO_2/CH_4释放影响因子,碳"源""汇"评估及人类活动影响四个方而综述了国内外湿地碳循环方面的研究工作.认为当前对湿地碳排放过程各种潜在的影响因素比较清楚,但碳排放过程各种影响因子之间存在的交互作用有待于进一步深入研究.在进行不同湿地类型碳循环研究的同时,应加强包括微生物、植物根系等地下碳动态研究,加强碳、氮耦合研究.在评估人类活动对湿地碳循环的影响过程中,要综合考虑植被碳库、土壤碳库及土壤碳排的变化.另外,无论从认识不同湿地类型碳过程特征及机理的角度,还是从减少全球或区域碳收支估测不确定性的角度来看,加强数据缺乏地区的湿地类型的碳平衡及相关碳过程的研究都具有重要意义.     

A critical review of the compassionate conservation debate

Compassionate conservation holds that compassion should transform conservation. It has prompted heated debate and has been criticized strongly. We reviewed the debate to characterize compassionate conservation and to philosophically analyze critiques that are recurring and that warrant further critical attention. The necessary elements of compassionate conservation relate to the moral value of sentient animals and conservation and to science and conservation practice. Although compassionate conservation has several nontraditional necessary conditions, it also importantly allows a degree of pluralism in values and scientific judgment regarding animals and conservation practice. We identified 52 specific criticisms from 11 articles that directly critique compassionate conservation. We closely examined 33 of these because they recurred regularly or included substantial questions that required further response. Critics criticized compassionate conservation's ethical foundations, scientific credentials, clarity of application, understanding of compassion, its alleged threat to conservation and biodiversity. Some criticisms, we found, are question begging, confused, or overlook conceptual complexity. These criticisms raise questions for critics and proponents, regarding, for example, equal versus differential intrinsic moral value of different sentient animals (including humans), problems of natural and human-caused suffering of wild animals and predation, and the acceptability of specific conservation practices within compassionate conservation. By addressing recurring and faulty critiques of compassionate conservation and identifying issues for compassionate conservation to address, this review provides a clearer basis for crucial ongoing interdisciplinary dialogue about ethics, values, and conservation.