Chlorinated dibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxins and dibenzofurans in the baltic herrinj and sprat of estonian coastal waters

BACKGROUND, AIMS AND SCOPE: The concentration of chlorinated dibenzo-p-dioxins and dibenzofurans in many fish from the Baltic requires monitoring, since it approaches or exceeds the European Union threshold limit value of 4 pg TEQ/g wet weight of fish for human consumption. The concentrations, expressed in TEQs, are important for toxicology and regulations, but hide the concentrations of the individual congeners, which are important for other environmental sciences, source allocation, and for the detection of measurement errors. This report evaluates the results of a survey reported earlier only in the terms of the TEQ concentrations. METHODS: Principal Component Analysis (PCA) was used to reduce the dimensions of the data (17 = 7 chlorinated dibenzo-p-dioxin and 10 chlorinated dibenzofuran congeners) to three principal components. This facilitated the interpretation of the congener profiles. Slopes of the congener concentrations as a function of age of the fish were estimated by least squares regression. The results were compared with a large set of data for lake trout from Lake Ontario. RESULTS AND DISCUSSION: The congener profiles of Baltic herring are less scattered than those of sprat. The profiles of herring from the central Baltic differ from those of herring from the Gulf of Riga and both appear to be affected relatively minimally by the age of the fish. The congener profiles of herring from the western Gulf of Finland are similar to those from the central Baltic, those from middle Gulf of Finland are similar to those from the Gulf of Riga. Both seem to be more affected by age of the fish than the profiles of the first two groups. The concentrations of several pentachloro- and hexachloro-dibenzo-p-dioxins and dibenzofurans increase with the age of the fish CONCLUSION: PCA is a good technique for the evaluation of the congener profiles. The resulting loading and score plots provide a good graphic summary of the multidimensional data. Additional analyses are needed to confirm the observed profile patterns. A comparison with the results of a long-term monitoring from another area shows that the age of the fish is a more important factor than the year of capture. RECOMMENDATION AND OUTLOOK: The surveys should continue for a number of years and the results should be presented and evaluated both in terms of the TEQs as well as in terms of weight concentrations. Since the concentrations do not appear to change very much from year to year, it would be better to carry out surveys only every 3-4 years and, instead, stratify the sampling according to age and gender of the fish, and to analyze replicate extracts by replicate measurements. The inclusion of unmarked replicate samples would be a good quality assurance measure. It would be desirable to analyze additional parts of the food chain in order to understand the fate of the compounds in the ecosystem.     

感潮港口多时段船舶引航过程风险仿真模型

为研究感潮港口船舶在不同潮时进港靠泊的引航过程风险演化规律,以优化泊位利用率和提高港口的生产效率,有必要进行多时段船舶引航过程风险的动态仿真。在对船舶引航任务场景和历史数据进行分析的基础上,采取HHM方法构建船舶引航过程的关键风险指标体系,采用AHP-CRITIC方法结合风险因素的主客观分布特点获取不同引航阶段中各指标权重,最后利用不确定人工智能云模型进行多时段船舶引航过程风险的建模仿真。通过某集装箱船的感潮水域引航过程场景分析,融合采样点的客观数据和专家知识对6个靠泊窗口期船舶引航过程风险进行动态仿真。结果表明:船舶引航过程风险演化整体呈U形曲线模式,相比正常航行阶段风险值,船舶引航初始和靠泊阶段风险值高60%左右;感潮港口6个窗口期的船舶引航过程风险略有差异,潮高、潮流对船舶交通流和起锚、靠泊作业安全影响明显。     

特厚倾斜煤层采空区对公路路基沉降影响研究

为了研究采空区导致上覆复杂岩层运移致使公路路基沉降问题,以颗粒流理论为基础,通过下落法构建模型。根据煤层位置,假设了7种采空区长度进行模拟。模拟的结果为岩层应力、应变在不同情况下的最终状态,同时提出了影响区和松散堆积区的概念。结果表明,由于岩层构造复杂,在不同情况下主要影响区和松散堆积区的发展变化是不同的,特别是岩层4的作用较为特殊。根据公路路基设计规范,采空区只限于假设1和假设2的采空区范围内,路基沉降才能满足规范要求。     

受限水域船舶积压风险测度方法研究

为了系统、客观地评估受限水域船舶积压衍生风险,实现对船舶积压风险的防控,进行船舶积压风险测度方法的研究。阐述了受限水域船舶积压风险的3种表现形式,提炼了风险表现形式的测评指标,提出了受限水域船舶积压指数,并建立了以二元Logistic回归为核心的风险测度模型,对积压风险测评指标进行量化处理,最后通过对三峡-葛洲坝枢纽船舶积压风险的实证分析验证测度方法的可行性。结果表明,受限水域船舶积压风险测度方法可以根据水域特征筛选积压风险主要测评指标,并最终得到积压衍生风险发生概率预测公式,预测并判断相应水域某一时期的船舶积压衍生风险严重程度,对实时测度和降低受限水域船舶积压风险、完善受限水域船舶通航安全预警和相关软件开发运用具有重要意义。     

Determination of total hydrocarbon concentration in coastal waters and sediments off the east coast of Peninsular Malaysia

To determine the level of total hydrocarbon concentrations (THCs) along the eastern coastal regions of Peninsular Malaysia, samples of subsurface seawater (1 m) and surface sediments were collected from several sampling stations between June and August 1993. THCs in seawater and sediments as determined by fluorescence spectroscopy ranged from 1.4 to 21.8 µg L-1 (Seligi crude oil equivalents) and from 0.79 to 20.0 mg kg-1 (dry weight Seligi crude oil equivalents) respectively. In comparison to results obtained in similar surveys in Malaysian waters, the levels of THCs found in the present study were significantly lower indicating lower hydrocarbon contamination in the area studied.     

Characterization of environmental water samples using strontium and lead stable isotope compositions

A simple procedure using both cation and anion exchange chromatography has been applied in the study of lead and strontium isotope composition in rain and stream water samples from remote catchments in Scotland. Whereas the soil released strontium to stream waters, lead was removed from rain water and the concentrations in stream waters were very low. Highly precise analysis by thermal ionisation mass spectrometry proved necessary in the determination of strontium isotope composition. The ⁸⁷Sr/⁸⁶Sr ratio in rain water was close to that of marine strontium but the ratios in stream waters were constant and highly characteristic for the stream. In the case of the stream at the Sourhope site, the ratio (0.70798 ± 0.00005) was less than that in rain water and probably resulted from the weathering of one specific mineral. The results suggested that the ⁸⁷Sr/⁸⁶Sr ratios could be used as a stable isotope tracer of waters and to provide information on the weathering processes. Two major anthropogenic components of lead were identified in water samples. One had its origin in petrol additives whereas the other was probably of industrial origin. The low ²⁰⁶Pb/²⁰⁷Pb ratios observed in stream waters confirmed the lead as being of anthropogenic origin and the data suggested that there was a movement, albeit very small, of lead from the soil to waters.     

重庆地区酸化水体中几种元素形态特征初探

研究了碳、氮、硒和铝在酸化水体中的形态特征。被研究的典型酸化水体中４种元素的最主要的形态分别为ＤＯＣ、Ｓｅ（ＩＶ）和。分析了这些元素的形态与水体中３９种测定参数之间的相关性；探讨了几种主要形态与浮游植物、浮游动物和底栖动物的关系。     

重庆地区酸化水体中的浮游生物

对我国重酸雨区重庆市郊六个不同酸度水体中的藻类和浮游动物进行调查和比较的结果表明，酸化水体（ＰＨ＜５．０）中的藻类和浮游动物的种类数分别较同一地区正常水体的少４１．８８％５０．０％；细胞或个体密度分别较正常水体的少７０．０％和３４－６７％。轻度酸化水体（６．０＞ＰＨ＞５．０）的上述指标亦较正常水体的低，但不如酸化水体的明显。     

基于OLCI数据的福建近海悬浮物浓度遥感反演

悬浮物（TSM）是评估水质的重要指标,也是水色遥感反演的核心参数之一.海陆色度仪（OLCI）是新一代海洋水色传感器,具有良好的光谱及时空分辨率.为有效监测福建近海悬浮物浓度的时空变化,本文结合OLCI遥感数据和现场实测悬浮物浓度数据,使用CatBoost、随机森林和多元回归方法,分别构建悬浮物浓度反演模型,最后使用验证集对比分析不同模型的反演精度.结果表明,CatBoost模型估算精度最高,均方根误差（RMSE）为2.76 mg·L^-1,平均绝对百分比误差（MAPE）为23.67%,决定系数R²为0.89.使用CatBoost模型对2017—2018年多时相OLCI影像进行TSM浓度遥感反演,结果发现,福建近海TSM浓度变化显著,但总体呈现近岸高于远岸、北部高于南部、江河入海口和港湾处高于周围其他海域、春季高于夏季的时空分布特征.本研究可为福建近海的悬浮物浓度监测提供一种有效的方法,也进一步证明了OLCI影像良好的水色反演能力,可作为水质监测的有效遥感数据源.     

航道水域的船舶夜航环境风险评价

准确地识别航道水域夜航环境的风险因子并对其进行客观、合理地评价,可以有效规避该风险并保障航道水域船舶的夜航安全。在查阅分析大量文献的基础上,结合专家意见确定航道水域夜航环境风险评价指标体系,运用层次分析法和熵权法确定了各指标的主、客观权重。采用物元综合评价法对航道水域夜航环境风险进行评价,通过查阅相关标准和文献确定航道水域夜航环境风险因子的经典域和节域,将实测的定量定性指标数据代入关联函数计算得出对应等级的关联度,乘以权重向量后确定该水域环境的风险等级。选取天津港3条航道进行实例评价,结果表明,船舶在航道B夜航为低风险,在航道A和航道C夜航为一般风险,实例结果与航道实际情况一致,验证了该方法的有效性。