Challenges in assessing the toxic effects of polycyclic aromatic hydrocarbons to marine organisms: a case study on the acute toxicity of pyrene to the European seabass (Dicentrarchus labrax L.)

The acute toxicity (96 h) of pyrene (PY) to European seabass (Dicentrachus labrax) juveniles assessed in a semi-static bioassay (SSB) with medium renewal at each 12 h, and in a static bioassay (SB) without medium renewal was compared in laboratorial conditions (water PY concentrations: 0.07-10 mg L⁻¹). Main findings in the SSB that assessed mainly the toxicity of PY and its metabolites were: increased levels of bile PY metabolites in good agreement with the profile of lipid peroxidation levels (LPO) in exposed fish relating PY exposure and oxidative damage; increased levels of PY-type compounds in the brain indicating their ability to cross the blood-brain barrier; increased levels of these substances in liver and muscle which are edible tissues for humans thus raising concern on potential adverse effects on consumers of fish from PY contaminated areas; a significant inhibition of glutathione S-transferase activity suggesting its involvement in PY detoxication as toxicant scavenger; finally, an almost complete impairment of the swimming velocity at all the PY concentrations linking sub-individual to higher population level effects. In the SB, where the overall toxicity of PY, its metabolites and environmental degradation products was evaluated, 19% and 79% of PY decay in test media was found at 12 and 96 h, respectively. In general, the effects were similar to those of SSB but with significant effects being induced at higher PY concentrations indicating that the parental compound is more toxic than its environmental degradation products. The other main differences relatively to the SSB were: increased levels of PY-type substances in the liver suggesting more accumulation in this organ. Therefore, these findings highlight the need of carefully considering experimental design options when assessing the toxicity of readily degradable substances to marine fish, and stress the importance of taking into consideration the toxicity of environmental degradation products in addition to toxic effects of the parental substance and its metabolites for marine ecological risk assessment.     

Estimation of thyroid doses and health risks resulting from the intake of radioactive iodine in foods and drinking water by the citizens of Tokyo after the Fukushima nuclear accident

The release of radioactive materials from the Fukushima nuclear power plant after the Great East Japan Earthquake on 11 March 2011 poses health risks. In this study, the intake of iodine 131 (I-131) in drinking water and foods (milk, dairy products, and vegetables) by citizens of Tokyo was estimated. The effects of countermeasures (restrictions on the distribution of foods and the distribution of bottled water for infants) on reducing intake were also evaluated. The average thyroid equivalent doses without countermeasures from 21 March 2011 were 0.42 mSv in adults, 1.49 mSv in children, and 2.08 mSv in infants. Those with countermeasures were 0.28, 0.97, and 1.14 mSv respectively, reductions of 33%, 35%, and 45%. Drinking water contributed more to intake by adults and children than foods. The intake of I-131 within the first 2 weeks was more than 80% of the estimated intake, owing to its short half-life, indicating that rapid countermeasures are important in reducing intake. The average risks of cancer incidence and mortality due to I-131 for infants were estimated to be 3 × 10⁻⁵ and 0.2 × 10⁻⁵, respectively, lower than the annual risks of traffic accidents, naturally occurring radioactive material (potassium 40), and environmental pollutants such as diesel exhaust particles.     

Assessment of DDT and mercury levels in fish and sediments in the Iriri River,Brazil: Distribution and ecological risk

Abstract

In order to assess the risk of exposure of human populations to dichlorodiphenyltrichloroethane (DDT) and mercury, muscles of five fish species were analysed, along with the surface sediment of 14 Iriri River sampling sites. The fish specimens were sacrificed by the spinal section, prior to sex identification, body weight determination and total length. Considering the fish specimens studied, 11% of them showed concentrations of mercury higher than the maximum established by the World Health Organization for safe human consumption. A positive correlation between fish body weight and mercury concentration was observed, besides a positive correlation between the fish size and Hg concentration. Significant differences (P?<?0.05) were found between mean concentrations of DDT and metabolites among species of fish studied. In the Plagioscion squamossissimus species, the highest concentration of total DDT (151.4?ng/g) was found, while in Eugerres Brasilianus species, the lowest. However, the DDT levels in fish muscle of studied species are below the maximum set by FAO-Alimentarius CODEX. In the sediments, total DDT ranged from 11.58?ng/g to 48.4?ng/g, which is associated with the historical DDT use in the Amazon. According to sediment quality guidelines, these levels have a moderate toxic effect in almost all of the studied region.     

Phytotoxic activity of crop residues from Burdock and an active substance

Abstract

Problems related to weed management such as outbreaks of herbicide-resistant weeds have recently increased. An interesting approach to such problems is to use plant materials with phytotoxic activity. Burdock (Arctium lappa L.) is a biennial herb belonging to Asteraceae and is cultivated in several countries. The present study investigated the phytotoxic activity of burdock and its active substances. Extracts of both burdock leaves and roots inhibited the shoot and root growth of cress and barnyard grass, where the level of inhibition increased with increasing extract concentration. The leaf extracts had 2.0–2.5 times higher activity than the root extracts. Bioassay-guided separations of the leaf extracts led to isolation of a phytotoxic substance, onopordopicrin. Onopordopicrin significantly inhibited the shoot and root growth of cress and barnyard grass. The concentrations of the substance required for 50% growth inhibition were 0.27 and 0.26?mM for cress shoots and roots, respectively, and 1.86 and 0.35?mM for barnyard grass shoots and roots, respectively. The present results suggest that burdock leaves have high phytotoxic activity and onopordopicrin may play a major role in the activity. Burdock leaves may be a good resource for weed management.     

采油废水中多环芳烃的生态风险评价

先利用C-18固相萃取小柱富集大港油田港东联合处理站污水处理站的采油废水中16种多环芳烃(PAHs,即萘、苊烯、苊、芴、菲、蒽、荧蒽、芘、、苯并[a]蒽、苯并[b]荧蒽、苯并[k]荧蒽、苯并[a]芘、茚并[1,2,3-cd]芘、二苯并[a,h]蒽和苯并[g,h,i]苝),再用气相色谱/质谱(GC/MS)分析测定其浓度,以评价PAHs的去除率和生态风险。结果表明:(1)采油废水经处理后,COD、石油类去除率分别达到82.27%、91.06%;外排水COD、石油类达到《污水综合排放标准》(GB 8978—1996)一级标准要求,优于中国采油废水处理的一般水平。(2)采油废水主要以2、3环的PAHs为主,约占总量的93%以上。(3)苯并[a]芘超过《地表水环境质量标准》(GB 3838—2002)中限值。(4)处理前的采油废水中蒽、菲和苯并[a]芘具有一定的生态风险;处理后的外排水中萘、蒽、菲、荧蒽、苯并[a]芘的暴露浓度(PEC)/预测无效应浓度(PNEC)均小于1,目前尚未对环境造成威胁。但是8种PAHs(苊烯和苯并类PAHs除外)总和表现出较大的毒性,需要引起重视。     

西安市大气中多环芳烃的季节变化及健康风险评价

对西安市2009年6月-2010年5月空气中的总悬浮颗粒（TSP）和气态样品进行了连续采样,利用GC—MS对16种PAHs进行分析。∑PAHs浓度（气相＋颗粒相）范围为39．93～1032．46ng／m^3,平均值为197．34ng／m^3;其中,冬季大气中∑PAHs浓度最大,相对浓度的范围为31．21％～72．98％,而夏季的浓度最小;检测出16种2～6环的PAHs,其中以3—4环为主。利用特征分子比值法和因子分析进行源解析,发现研究区PAHs的主要来源为燃煤和机动车尾气排放。通过苯并（a）芘（BaP）等效毒性（BEQ）和苯并（a）芘等效致癌浓度（BaPE）进行健康风险评价,结果显示,西安大气中PAHs的毒性具有明显的季节差异,特别是秋季和冬季大气中PAHs对人类的健康存在较大的潜在威胁。     

“地球工程”作为减缓气候变化手段的几个关键问题

减缓气候变化可以在大的地理尺度上以工程技术手段来实施。地球工程包括所有能源生产和消费以外的、不涉及工业生产过程管理的,在较大的地球尺度或规模上,去除大气中的CO2或直接控制太阳辐射而降温的各种人为的工程技术手段,主要包括三大类:绿色生物技术手段、碳捕获与埋存技术和太阳光辐射额度控制管理技术。这一类地球工程手段有着一系列经济、技术、环境、伦理、安全和不确定性含义。本文就近年来国际上关于地球工程作为减缓气候变化可能技术选择的几个关键问题开展了分析和讨论,涉及概念界定、技术特点、可能影响、治理构架等。作者认为,对于直接作用于碳的地球工程手段,如绿色生物技术手段和碳捕获与埋存技术,风险小、可操控;太阳光辐管理技术,通过人为排放到大气的SO2和气溶胶等的降温效应,来控制地球气温的上升,尽管使用的经济成本可能不高,具有实际操作可能,但其巨大的不确定性和可能的安全含义,需要引起足够的重视。从伦理上看,当代人是否有权来开展太阳光辐管理技术这类具有巨大科学不确定性的地球工程存在争议,在科学不确定的情况下采取任何行动,就失去了伦理学基础。从法律上看,人工干预太阳辐射,即使是科学实验或研究,由于其影响超出了国界,超出了当代人,也超出了人类社会,如果有人采取行动,也存在法律依据上的质疑。人工干预太阳辐射的研究和实施,需要一个国际治理构架。为了防止其他国家单独行动,需要"相互约束"的治理构架——"自我约束"以换取他国同意"自我约束"。鉴于气候变化和光辐管理在科学上的不确定性,目前不宜实施,短期内也不会提上议事日程。太阳光辐管理技术影响的复杂性和气候变化风险的迫切性,需要我们加大科学研究力度,为科学决策提供依据。中国作为一个新兴经济体,世界第一大CO2排放国,地域空间气候条件存在巨大差异性。从减排成本的角度,从气候影响的空间差异性,开展地球工程的科学研究,有着科学、政策和国际气候外交的积极意义。但是,相关的科学研究需要国际制度构架。由于气候变化框架公约及其谈判尚未涉及,需要开展系统科学、技术、经济、法律和国家安全等方面的相关研究,提高科学认知度,为国际谈判和政策选择提供决策依据。     

土地督察对土地违法的遏制效应评价

选择当年发生土地违法案件数和当年发生土地违法涉案面积作为主要表征指标,收集了2002-2009年的省级面板数据,分析土地督察对土地违法是否有影响以及影响的程度。论文分别采用了固定效应模型、随机效应和混合OLS模型加以估计,通过相关检验,最后选用了固定效应模型的估计结果。在模型估计结果的基础上,对土地督察的违法遏制效果进行了评价。分析表明:①土地督察的确对减少土地违法有显著影响,土地例行督察覆盖度每提高1%,可能减少土地违法案件92件,可能使土地违法涉案面积减少约2.18%;②若对某省份实施了专项督察,则可能减少土地违法案件7件,可能使土地违法涉案面积减少31.11%;③由于实行了土地例行督察和专项督察,可能使2007-2009年的土地违法案件分别少发生84件、3 473件和12 500件,土地违法涉案面积分别少发生2 314.13 hm2、1 919.75 hm2和3 046.57 hm2。     

A contextual framework for understanding good practice in integrated catchment management

Principles of good practice for collaborative resource management were derived from the literature and their use studied in a range of integrated catchment management processes. Desk-based reviews and interviews with participants allowed the principles to be refined and described within a framework that illustrates the interrelationships between core principles, enabling principles, precursors to a project and the influence of external factors on such collaborative processes. The findings illustrate the importance of these relationships in understanding how success is defined and under what conditions successful outcomes can be achieved. Understanding how these procedural aspects influence outcomes contributes to the wider literature on collaborative resource management that often treats processes separately from their context.     

Relation between management's behavioural intentions toward the environment and environmental actions

Drawing on Ajzen's Theory of Planned Behaviour, this paper analyses whether there is a relation between management's behavioural intentions toward an environmental problem and the company's specific actions in this area, and also considers the impact of the company size on these actions. For the data, a questionnaire was sent to 184 managers employed in industrial companies located in Spain which belonged to the automobile industry. The empirical analysis produces positive and significant regression coefficients and provides support for the hypotheses proposed. Specifically, the results show that the environmental actions carried out in the company respond at least in part to management's behavioural intentions toward these issues and the size of the firm.