Speciation of heavy metals in estuarine sediments in the northeast of Brazil

An analytical procedure involving a three-step sequential extraction was used to determine the chemical association of heavy metals (Zn, Cr, Mn and Fe) with the major phases (exchangable, reducible and oxidizable) in samples from a fishpond of estuarine sediments. The pond is located in the Capibaribe River estuary, within the boundaries of the city of Recife, in the State of Pernambuco in the northeast of Brazil. The total metal content was determined as well. All metals were extracted from the residual fraction at a percentage greater than 50%.     

A voltammetric screening method to determine ronidazole in bovine meat

Abstract

An original voltammetric screening method, employing glassy carbon electrode (GCE) with the differential-pulse voltammetry technique (DPV), has been developed to determine residues of the anti-parasitic agent Ronidazole (RNZ) in bovine meat. By using cyclic voltammetry (CV), it has been demonstrated that an irreversible cathodic process occurs at approximately ?0.740?V (vs. Ag|AgCl, KCl 3?mol L^?1) in a 0.100?mol L^?1 phosphate buffer at pH 6.5 as supporting electrolyte. Furthermore, the behavior of RNZ in CV indicates the occurrence of a diffusion mass transfer process to the working electrode surface. The RNZ reduction mechanism was proposed as a 6-electron transfer, similar to Metronidazole under the same pH range. Quantification of RNZ and method validation were then carried out by DPV. The relative standard deviation (RSD) were 3.21% for intraday precision of 10 consecutive repetitions and 6.78% for interday precision after five analysis. Limits of detection and quantification were also obtained, and the values were 0.107 and 0.358?mg kg^?1, respectively. The recovery percentage for three different concentrations of RNZ in the bovine meat matrix ranged between 98.1% and 100.3%. The method proved to be efficient for screening RNZ in bovine meat.     

Did the Romans introduce the Egyptian mongoose (<Emphasis Type="Italic">Herpestes ichneumon</Emphasis>) into the Iberian Peninsula?

New finds of bones of the Egyptian Mongoose (Herpestes ichneumon), one from Portugal and one from Spain, were directly ¹⁴C dated to the first century AD. While the Portuguese specimen was found without connection to the Chalcolithic occupation of the Pedra Furada cave where it was recovered, the Spanish find, collected in the city of Mérida, comes from a ritual pit that also contained three human and 40 dog burials. The finds reported here show that the Egyptian mongoose, contrary to the traditional and predominant view, did not first arrive in the Iberian Peninsula during the Muslim occupation of Iberia. Instead, our findings are consistent with the hypothesis that the species was first introduced by the Romans, or at least sometime during the Roman occupation of Hispania. Therefore, radiocarbon dating of new archaeological finds of bones of the Egyptian Mongoose (Herpestes ichneumon) in the Iberian Peninsula push back the confirmed presence of the species in the region by approximately eight centuries, as the previously oldest dated record is from the ninth century. With these new dates, there are now a total of four ¹⁴C dated specimens of Egyptian mongooses from the Iberian Peninsula, and all of these dates fall within the last 2000 years. This offers support for the hypothesis that the presence of the species in Iberia is due to historical introductions and is at odds with a scenario of natural sweepstake dispersal across the Straits of Gibraltar in the Late Pleistocene (126,000–11,700 years ago), recently proposed based on genetic data.     

The determinants mostly disclosed by companies that are members of the Carbon Disclosure Project

Concerns about climate change as a result of anthropic actions have led to an increase in the volume of information disclosed about it in the reports of companies that are members of the Carbon Disclosure Project (CDP). In this context, the factors most disclosed remain obscure due to both the complexity of climate change impacts and the stakeholders’ different interests. This study aims to identify which factors are most disclosed in the reports of companies that are members of CDP. For this purpose, it is necessary to investigate if the factors indicated by managers and experts are the main ones disclosed in the reports of Brazilian companies that are members of CDP, as well as to identify which companies stand out in climate change disclosure based on these factors. To this end, 463 reports submitted by 48 companies between 2014 and 2016 were examined and 32 factors were investigated using the NVivo® software. Some companies submitted reports with unified titles, which reduced the sample. The results indicate that certain factors—prevention of pollution, prevention of loss, management of environmental assets, volume of greenhouse gas (GHG) emissions, and climate change strategy—account for 50.03% of the total volume of information disclosed about climate change. The main lesson learned from this research is that climate change mitigation strategy is strongly supported by the evidence of corporate annual reports, and it has relation with the following determinant factors: pollution prevention, loss prevention, environmental asset management, GHG emissions, and the strategy chosen by the companies to deal with climate change. Due to the low volume of research related to loss prevention and pollution prevention, we have identified that little attention has been paid to these items. Based on our results, we recommend that climate change mitigation strategies begin to consider these determinant factors in their structure because both have a strong influence in demonstrating how companies are managing these factors for stakeholders. Therefore, companies can benefit from this data to manage their resources for the maintenance of the social contract (legitimacy) through the factors most disclosed, especially companies with lower scores on the scale of ranking presented. Hence, stakeholders can have access to more information on strategies that mitigate climate change and help companies improve the disclosure of the actions that contribute to reduction of GHG emissions.     

Disclosure of climate risk information by the world’s largest companies

The risks related to global climate change are seen as threats to companies, taking into consideration their impact on the return on investment. In order to mitigate climate risk and introduce new opportunities to financiers, companies need to identify, manage, and report climate risks. The purpose of this paper is to investigate the climate risks disclosed by the 100 largest companies in the world, according to the Bloomberg and Price Waterhouse Coopers (PwC 2015) classification, and identify some characteristics of these companies that explain the disclosure level of such information. Preliminary results revealed that of the companies investigated, 14% did not disclose any climate risk information in the Carbon Disclosure Program (CDP) report. Also, from the companies that disclosed information according to the Global Reporting Initiative (GRI), 9.9% did not provide information regarding policies, actions, and strategies for mitigating the risks related to climate change. The results shown by the content analysis suggested that, in general, there is still a low level of disclosure about climate risks by these companies. The final results through econometric instruments and statistical tests indicate that the size of the company or the fact that corporations are from developed countries do not necessarily explain the level of information disclosed. However, the activity sector, the continent, and the efficiency of the Board of Directors are factors that strongly explain the level of climate risk disclosure. We conclude that more effort is needed to encourage an engaging attitude from corporations to develop actions, policies, and strategies to mitigate climate change risks and threats. In addition, the world’s largest companies should make a greater investment in climate risk disclosure.     

PCR-SSCP技术用于脱臭微生物群落结构的研究

采用PCR-SSCP(单链构象多态性)技术对脱臭生物滤池中填料生物膜微生物群落结构进行了研究.生物滤池对臭气中的污染物随驯化时间逐渐增强,去除率从50%升高到89%.对2种填料树皮和秸秆上生物膜的分析结果表明,滤池内微生物多样性随运行时间先降后升,从1.6～1.9上升到2以上;而2种填料上微生物的相似性逐渐增加,表明随着驯化进程,生物填料上的微生物能够利用臭气污染物进行生长,并随运行时间逐渐趋于丰富和稳定;树皮比秸秆具有较高的生物多样性,平均值分别为2.2和2.0,说明树皮上容易附着多种微生物生长,电镜照片也显示2种填料生物膜的增长和生物多样性的提高.SSCP条带测序结果表明生物滤池生物膜优势微生物种属为芽孢杆菌属,占33.3%;条带中不可培养细菌占44.4%;填料生物膜上的细菌绝大多数是广泛存在于土壤、水体及生物体中的微生物,它们对环境适应能力强,在臭气的污染物去除中扮演重要角色.     

基于博弈赋权物元和证据理论的无线闭塞中心风险评估*

为客观地对无线闭塞中心进行风险评估,建立基于博弈赋权物元和证据理论的评估模型,根据故障树分析法识别的风险因子构建评估指标体系,采用博弈论思想对直觉模糊层次分析法计算的主观权重和熵权法计算的客观权重进行最优组合,进而确定综合权重。运用物元理论和证据理论确定各指标的风险等级和系统整体风险等级,并通过实例分析对评估模型进行对比验证。结果表明:无线闭塞中心整体风险等级为“可容许的”,与实际情况相符。其中,系统外部通信故障的风险等级为“不期望的”,需要对其相关设备加强风险控制。     

The Effects of Irrigation and Climate on the High Plains Aquifer: A County‐Level Econometric Analysis

The High Plains Aquifer (HPA) underlies parts of eight states and 208 counties in the central area of the United States (U.S.). This region produces more than 9% of U.S. crops sales and relies on the aquifer for irrigation. However, these withdrawals have diminished the stock of water in the aquifer. In this paper, we investigate the aggregate county‐level effect on the HPA of groundwater withdrawal for irrigation, of climate variables, and of energy price changes. We merge economic theory and hydrological characteristics to jointly estimate equations describing irrigation behavior and a generalized water balance equation for the HPA. Our simple water balance model predicts, at average values for irrigation and precipitation, an HPA‐wide average decrease in the groundwater table of 0.47 feet per year, compared to 0.48 feet per year observed on average across the HPA during this 1985–2005 period. The observed distribution and predicted change across counties is in the (?3.22, 1.59) and (?2.24, 0.60) feet per year range, respectively. The estimated impact of irrigation is to decrease the water table by an average of 1.24 feet per year, whereas rainfall recharges the level by an average of 0.76 feet per year. Relative to the past several decades, if groundwater use is unconstrained, groundwater depletion would increase 50% in a scenario where precipitation falls by 25% and the number of degree days above 36°C doubles. Editor’s note : This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series.     

Winners and Losers in a World with Global Warming: Noncooperation, Altruism, and Social Welfare

In this paper, global warming is an asymmetric transboundary externality which benefits some countries or regions and harms others. We use a simple two-country model to analyze the effects of global warming on resource allocations, the global-warming stock, and national and global welfare.     

The relevance of James Lovelock’s research and philosophy to environmental science and academia

James E. Lovelock, famed for his Gaia hypothesis, which views the Earth as a living integrated and interconnected self-regulating system whose equilibrium comes about from complex energy-based interactions and feedback loops, ultimately sustaining life, passed away at the end of July, 2022 at the age of 103. Not only are the adaptive mechanisms of Gaia central to the conversation of environmental homeostasis, they lie at the heart of climate change and global warming. Lovelock is also remembered as the co-inventor of the electron capture detector that eventually allowed for the sensitive detection of chlorofluorocarbons and pesticides. Finally, Lovelock’s free-spirited nature and research independence allow academia to rethink current research’s modus operandi.