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。     

Integrating geochemical (surface waters, stream sediments) and biological (diatoms) approaches to assess AMD environmental impact in a pyritic mining area: Aljustrel (Alentejo, Portugal)

Aljustrel mines were classified as having high environmental hazard due to their large tailings volume and high metal concentrations in waters and sediments.To assess acid mine drainage impacted systems whose environmental conditions change quickly,the use of biological indicators with short generation time such as diatoms is advantageous.This study combined geochemical and diatom data,whose results were highlighted in 3 groups:Group 1,with low p H(1.9–5.1)and high metal/metalloid(Al,As,Cd,Co,Cu,Fe,Mn,Ni,Pb,Zn;0.65–1032 mg/L)and SO_4(405–39124 mg/L)concentrations.An acidophilic species,Pinnularia aljustrelica,was perfectly adapted to the adverse conditions;in contrast,teratological forms of Eunotia exigua were found,showing that metal toxicity affected this species.The low availability of metals/metalloids in sediments of this group indicates that metals/metalloids of the exchangeable fractions had been solubilized,which in fact enables metal/metalloid diatom uptake and consequently the occurrence of teratologies;Group 2,with sites of near neutral p H(5.0–6.8)and intermediate metal/metalloid(0.002–6 mg/L)and SO_4(302–2179 mg/L)concentrations;this enabled the existence of typical species of uncontaminated streams(Brachysira neglectissima,Achnanthidium minutissimum);Group 3,with samples from unimpacted sites,showing low metal/metalloid(0–0.8 mg/L)and SO_4(10–315 mg/L)concentrations,high pH(7.0–8.4)and Cl contents(10–2119 mg/L)and the presence of brackish to marine species(Entomoneis paludosa).For similar conditions of acidity,differences in diversity,abundance and teratologies of diatoms can be explained by the levels of metals/metalloids.     

Phenol transformation induced by UVA photolysis of the complex FeCl<Superscript>2+</Superscript>

Here we show that the photolysis of FeCl²⁺ upon UV irradiation of Fe(III) at pH 0.5, yielding Cl^• and then Cl₂^−•, upon further reaction with Cl⁻, induces phenol degradation. The photolysis of FeCl²⁺ can be highlighted and studied as the huge interference by FeOH²⁺ can be avoided under such conditions. Our data allowed the assessment of a photolysis quantum yield for FeCl²⁺ of 5.8 × 10⁻⁴ under UVA irradiation, much lower compared to the literature value of 0.5. The discrepancy can be explained if the photolysis process is efficient but photoformed Fe²⁺ and Cl^• undergo recombination inside the solvent cage.     

Solar and Tidal Modulations of Fecal Indicator Bacteria in Coastal Waters at Huntington Beach,California

The coastal waters at many beaches in California and the United States are afflicted with fecal pollution, which poses a health risk for people exposed to the water through recreational activities such as swimming, surfing, and diving. Identifying sources of pollution is complicated by oceanographic transport/mixing processes and the nonconservative behavior of microorganisms exposed to sunlight and hostile marine conditions. This article investigates the variation of fecal indicator bacteria (FIB) concentrations in the surf zone and the adjacent coastal marsh by applying autocorrelation and cross-correlation analyses that illustrate solar and tidal modulations. A steady state bioreactor model was developed to explain solar inactivation in the surf zone, whereas a dynamic model was applied to explain tidally influenced disturbances in the coastal marsh. These models applied to intensive monitoring datasets on FIB and environmental variables have provided insights into the biologic and physical processes controlling coastal water quality, specifically the influence of sunlight and tides on bacterial levels.