Determination of Commonly Used Herbicides in Surface Water Using Solid-Phase Extraction and Dual-Column HPLC-DAD

The present study describes the application of different solid-phase extraction techniques for the extraction, separation, and quantitative determination of 10 commonly used herbicides with different chemical structures (chlorsulfuron, diuron, bentazone, linuron, chlorpropham, fenoxoprop-ethyl, MCPA, diclofop-methyl, fluazifop-butyl, trifluraline) in water. Octadecyl (C₁₈) Empore extraction disks, octadecyl (C₁₈), and stryene divinylbenzene (SDB) Bond Elut Env cartridges were compared for solid-phase extraction efficiency. Herbicides were separated and quantified by reversed-phase high performance liquid chromatography with diode-array detection (HPLC-DAD) with simultaneous separation on two columns of differing polarity (C₁₈ and CN) to confirm identification. Analytical separation was performed simultaneously on C₁₈ and CN columns. Reanalysis of the sample extracts on a (cyano) CN column were used to confirm the identity of these compounds. Method optimization and validation parameters were presented in this work. Recoveries varied from 76.0% to 99.0% for C₁₈ disks, from 75.1% to 100.0% for C₁₈ cartridges, and from 54.0% to 98.0% for SDB cartridges over concentrations at 0.025–0.4 μg L^?1. The limits of detection were 0.012–0.035 μg L^?1.     

Factors affecting the flux of arsenic through the mussel Mytilus galloprovincialis

Radiotracer experiments were designed to study the effects of certain environmental and biological factors on arsenic accumulation and elimination processes in the Mediterranean mussel Mytilus galloprovincialis. Arsenic (as arsenate) uptake increased with increasing arsenic concentration in the water; however, the response was not proportional, indicating that accumulation was partially suppressed at higher external arsenic concentrations. In general, approximately 80% of the ⁷⁴As taken up was associated with the soft parts, with small mussels concentrating ⁷⁴As to a greater degree than larger individuals. The highest ⁷⁴As concentrations were recorded in the byssus and the digestive gland. Increased temperature enhanced both arsenic uptake and loss. Mussels in sea water at 19 S accumulated approximately three times more ⁷⁴As than those held at 38 S. Arsenic loss was much less affected by salinity, with only a tendency for greater arsenic retention noted at lower salinities. Studies carried out in the laboratory and in situ revealed that arsenic turnover was significantly more rapid in actively growing individuals living under natural conditions. Arsenic-74 loss from the in situ group was essentially biphasic, with biological half-times of approximately 3 and 32 days for the fast and slow compartments, respectively. The active secretion of arsenic in the byssal threads contributed to the total elimination of the element from the mussels.     

Rheological and Mechanical Properties of Poly(lactic acid)/Bio-Based Polyethylene/Clay Biocomposites Containing Montmorillonite and Vermiculite Clays

Journal of Polymers and the Environment - This work aims to investigate the effect of organically modified montmorillonite (OMMT) and vermiculite (OVT) clays on the properties of poly(lactic acid)...     

Shift of Spawning Season and Effects of Climate Warming on Developmental Stages of a Grayling (Salmonidae)

Abstract: River‐dwelling fish, such as European graylings (Thymallus thymallus), are susceptible to changes in climate because they can often not avoid suboptimal temperatures, especially during early developmental stages. We analyzed data collected in a 62‐year‐long (1948–2009) population monitoring program. Male and female graylings were sampled about three times/week during the yearly spawning season in order to follow the development of the population. The occurrence of females bearing ripe eggs was used to approximate the timing of each spawning season. In the last years of the study, spawning season was more than 3 weeks earlier than in the first years. This shift was linked to increasing water temperatures as recorded over the last 39 years with a temperature logger at the spawning site. In early spring water temperatures rose more slowly than in later spring. Thus, embryos and larvae were exposed to increasingly colder water at a stage that is critical for sex determination and pathogen resistance in other salmonids. In summer, however, fry were exposed to increasingly warmer temperatures. The changes in water temperatures that we found embryos, larvae, and fry were exposed to could be contributing to the decline in abundance that has occurred over the last 30–40 years.     

污泥电解脱水过程中泥饼厚度变化研究

污泥电解脱水具有独特优势,但同时伴随电耗高、时空产率低等问题。为实现能耗优化,以污泥电解脱水过程中泥饼厚度的变化为切入点,通过小试装置原位探究厚度变化规律以及厚度变化与含水率之间的关系,通过观察垂直电场作用下厚度的变化,使含水率的变化更加直观和可控,并从密度和含水率入手,对厚度变化的机理进行简要分析。结果表明:电解脱水过程中泥饼厚度变化具有一定规律,当泥饼初始厚度较小时,泥饼厚度随含水率的降低而减小;当泥饼初始厚度较大时,泥饼厚度随含水率的减少呈先增大后减小的趋势。     

淹水和干湿交替对修复后土壤铬的稳定性影响研究

采用固化/稳定化技术修复后的场地和土壤因其污染物未彻底清除而备受关注,外界环境胁迫下重金属存在再活化的风险,但再活化的速率和形式尚不明确. 我国华南地区高温多雨,水热交换频繁剧烈,固化/稳定化后修复场地的安全利用面临更大的潜在风险. 以珠三角地区2个典型固化/稳定化修复后场地土壤为研究对象,开展淹水和干湿交替对土壤重金属铬(Cr)的释放、形态转化及其影响机制研究. 结果表明:①淹水和干湿交替可提高已固化/稳定化土壤中Cr的浸出浓度. 场地A和B土壤Cr的浸出浓度较淹水前分别上升了1.32和8.72倍,干湿交替后场地A土壤Cr的浸出浓度略有下降,场地B土壤Cr的浸出浓度则增加了4.32倍. ②淹水和干湿交替促使已固化/稳定化的Cr从酸可提取态向相对稳定的可氧化态等转化. 场地A和B土壤中酸可提取态Cr含量较淹水前的变化率分别为?60.17%和?14.34%,可氧化态Cr含量的变化率分别为2.71%和13.30%;干湿交替后土壤可提取态Cr含量的变化率分别为?28.78%和?2.13%,可氧化态Cr含量的变化率分别为5.48%和10.22%. ③淹水通过降低土壤氧化还原点位(E_h)、pH和无定形氧化铁等影响Cr的稳定性,促使Mn4+、Fe3+的还原和Cr的重新释放;干湿交替较淹水处理对固化/稳定化体系的影响相对较小. 研究显示,水分胁迫可提高固化/稳定化修复后土壤Cr的浸出浓度、改变赋存形态,但其浸出浓度远低于GB 5085.3—2007《危险废物鉴别标准 浸出毒性鉴别》和HJ/T 301—2007《铬渣污染治理环境保护技术规范(暂行)》规定的浸出液浓度限值;鉴于外界环境胁迫的长期性和复杂性,以及当前“一评定终身”的效果评估管理模式对未彻底清除污染物场地后期监管的无力性,持续关注和系统管控是实现固化/稳定化修复后场地可持续安全利用的必要途径.      

面向区域大气环境质量改善的京津冀及周边地区产业结构评估与优化建议

不合理的产业结构与布局是京津冀及周边地区大气污染严重的主要原因,开展区域产业结构与布局优化是有效改善区域大气环境质量的重要手段。应用产业结构相似系数法、产业结构偏离修正指数法及产业结构转移度量法分别定量评估京津冀及周边地区7个省(区、市)产业结构的趋同化、合理化及高级化程度,提出区域大气环境质量改善的产业结构优化对策。结果表明:京津冀及周边地区各省(区、市)之间产业结构相似系数逐年递增,且逼近1,存在较为严重的结构趋同现象;除北京市外,其他省(区、市)产业结构的合理化程度普遍较低,且改善速度较慢;区域产业结构高级化程度处于平缓上升趋势,北京市的产业结构高级化程度最高,其他省(区、市)普遍较低。未来应从明确各省(区、市)发展特征与定位、制定差异化发展策略、统筹优化产业布局、加快产业转移和整合等方面进行优化。     

锌冶炼用氧化锌富集物再生综合效益评价

针对锌冶炼用氧化锌富集物的再生效益进行评估,对推动锌再生资源利用的合理规划,支持环境管理的科学决策具有重要意义。以国内企业的调研结果为依据,建立包括经济效益、资源效益、环境效益和社会效益4个层面影响因素的氧化锌富集物再生综合效益评价指标体系;运用层次分析法（AHP）和基于指标相关性的权重确定方法（CRITIC）对指标进行组合赋权,再对采用黄金分割法划分的标准云进行修正,进而构建基于组合赋权-云模型的综合效益评价模型,并对江西某铅锌金属公司进行实例评价。结果表明：该企业氧化锌富集物再生制锌的综合效益水平较高,一级指标中资源效益水平高,环境、社会和经济效益水平较高,且环境效益和社会效益的评价结果不确定性更大。所得结果兼顾评价过程中的模糊性和随机性,提供了更加全面的锌冶炼用氧化锌富集物再生效益评价信息。

     

Generic foresight model in changing hygiene habits with the pandemic: use of wet wipes in next generations

Journal of Material Cycles and Waste Management - The vast use of wet wipes has now become a habitude, particularly following the altered perception of cleanliness during the pandemic and the...