Effects of vegetable oil residue after soil extraction on physical-chemical properties of sandy soil and plant growth

Vegetable oil has the ability to extract polycyclic aromatic hydrocarbons(PAHs)from contaminated sandy soil for a remediation purpose,with some of the oil remaining in the soil.Although most of the PAHs were removed,the risk of residue oil in the soil was not known.The objective of this study was to evaluate the effects of the vegetable oil residue on higher plant growth and sandy soil properties after soil extraction for a better understanding of the soil remediation.Addition of sunflower oil and column ex...     

卤水盆地在层状矿床形成中的作用

根据间隙溶液及其周围的盐下陆源地层岩石的研究,阐明了把地表蒸发盐盐水改造为含矿溶液的机制;研究了含矿盐水变为成矿溶液的可能途径。     

Water quality soft-sensor prediction in anaerobic process using deep neural network optimized by Tree-structured Parzen Estimator

● Hybrid deep-learning model is proposed for water quality prediction. ● Tree-structured Parzen Estimator is employed to optimize the neural network. ● Developed model performs well in accuracy and uncertainty. ● Usage of the proposed model can reduce carbon emission and energy consumption. Anaerobic process is regarded as a green and sustainable process due to low carbon emission and minimal energy consumption in wastewater treatment plants (WWTPs). However, some water quality metrics are not measurable in real time, thus influencing the judgment of the operators and may increase energy consumption and carbon emission. One of the solutions is using a soft-sensor prediction technique. This article introduces a water quality soft-sensor prediction method based on Bidirectional Gated Recurrent Unit (BiGRU) combined with Gaussian Progress Regression (GPR) optimized by Tree-structured Parzen Estimator (TPE). TPE automatically optimizes the hyperparameters of BiGRU, and BiGRU is trained to obtain the point prediction with GPR for the interval prediction. Then, a case study applying this prediction method for an actual anaerobic process (2500 m³/d) is carried out. Results show that TPE effectively optimizes the hyperparameters of BiGRU. For point prediction of COD_eff and biogas yield, R² values of BiGRU, which are 0.973 and 0.939, respectively, are increased by 1.03%–7.61% and 1.28%–10.33%, compared with those of other models, and the valid prediction interval can be obtained. Besides, the proposed model is assessed as a reliable model for anaerobic process through the probability prediction and reliable evaluation. It is expected to provide high accuracy and reliable water quality prediction to offer basis for operators in WWTPs to control the reactor and minimize carbon emission and energy consumption.     

Perfluoroalkane acids in human milk under the global monitoring plan of the Stockholm Convention on Persistent Organic Pollutants (2008–2019)

● Perfluorooctanesulfonic acid and perfluorooctanoic acid highest in human milk. ● All other perfluoroalkane substances had median values of zero (101 samples). ● Branched PFOS recommended to be analyzed separately from linear isomer. ● PFOS and PFOA showed differentiated regional and income distribution. ● Human health risk assessment values not yet available at global level. Within the global monitoring plan (GMP) established by article 16 of the Stockholm Convention on Persistent Organic Pollutants, perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonic acid (PFHxS) are recommended for analysis in core matrices to assess occurrence and changes geographically and with time. In 101 samples consisting of 86 national pools and 15 pools from States in Brazil obtained between 2008 and 2019, PFHxS was detected in 17% of the national pools and none in Brazil. PFOA and PFOS had a detection frequency of 100% and 92%, respectively. Other perfluoroalkane substances (PFAS) had either low detection frequencies and median values of zero (carboxylic acids C₄–C₁₁; except PFOA) or could not be quantified in any sample (sulfonic acids, C₄–C₁₀, and long-chain carboxylic acids, C₁₂–C₁₄). Correlation between PFOA and PFOS was moderately (r = 0.58). Whereas median values were almost identical (18.9 pg/g f.w. for PFOS; 18.6 pg/g f.w. for PFOA), PFOS showed larger ranges (< 6.2 pg/g f.w.–212 pg/g f.w.) than PFOA (< 6.2 pg/g f.w.–63.4 pg/g f.w.). It was shown that wealthier countries had higher PFOA concentrations than poorer countries. No difference in concentrations was found for samples collected in countries having or not having ratified the Stockholm Convention amendments to list PFOS or PFOA. The goal to achieve 50% decrease in concentrations within ten years was met by Antigua and Barbuda, Kenya, and Nigeria for PFOS and by Antigua and Barbuda for PFOA. In a few cases, increases were observed; one country for PFOS, four countries for PFOA.     

Arsenic species in electronic cigarettes: Determination and potential health risk

Human exposure to contaminants from electronic cigarettes(e-cigarettes) and the associated health effects are poorly understood.There has been no report on the speciation of arsenic in e-liquid(solution used for e-cigarettes) and aerosols.We report here determination of arsenic species in e-liquids and aerosols generated from vaping the e-liquid.Seventeen e-liquid samples of major brands,purchased from local and online stores in Canada and China,were analyzed for arsenic species using high-perfo...     

废塑料裂解生产原料油的研究

本文对聚乙烯和聚丙烯的混合物裂解成原料油进行了研究 ,在 44 0℃条件下 ,不同比例的聚乙烯和聚丙烯被裂解。结果发现 ,聚丙烯有最高的液体回收率。几种催化剂被应用到聚丙烯的裂解过程中。裂解产品组分的构成及催化剂的选择是本研究的主要内容。通过比较几种不同催化剂的催化结果发现 ,复合催化剂有更好的催化效果。本研究为将来的废塑料综合利用提供了一种新的有用方法     

钨矿床的生物地球化学找矿特征

<正> 有关钨矿床的生物地球化学研究成果已有许多报道。所获资料表明,利用钨被植物富集的特征作为生物地球化学标志,基本上是行不通的。所以,在进行钨矿床的生物地球化学找矿时,必需注意与具体钨矿化类型有成因联系的伴生元素。     

Emission Inventories of Carbon-containing Greenhouse Gases in China and Technological Measures for Their Abatement

The report summarizes surveys on carbon inventories and initiatives on sustainable carbon cycling taken by the Research Center for Eco-Environmental Sciences, where the authors work/worked. The first part of the report, which appeared in the preceding issue of this journal, deals with the concept of sustainable carbon cycling, the historic evolution of carbon cycling processes in China, carbon pool enhancement, value addition, carbon sequestration and carbon balance. This very paper, as the second part of the report, covers the results of carbon dynamics modeling, emission inventories of various carbon-containing greenhouse gases and their potential abatement measures.     

贱金属硫化物附近水中金属活动性的实验研究

前言 长期以来,勘探地球化学工作者认为,当远离矿带的天然水流过未扰动的贱金属硫化物矿床时,水中仅富集了Zn。因此,在地下水中Zn便成了一种有用的“示踪”或“指示”元素,而Cu、Pb、Fe是相对不活     

岩浆建造——岩石圈演化的指示剂

本文以大陆岩石圈发展历史中的核阶段、克拉通阶段和大陆海洋阶段的岩浆建造为线索,着重介绍了岩浆岩建造的全球性和区域性的指示作用,以助人们了解具体的大型大地构造及其个别单元的岩浆作用演化的规律性,以及正在演化的岩石圈内岩浆作用变化的总趋向。