Solid partitioning and solid-liquid distribution of Po and Pb in marine anoxic sediments: roads of Cherbourg at the northwestern France

A sequential extraction protocol has been used to determine the solid-phase partition of ²¹⁰Po and ²¹⁰Pb in anoxic marine sediment from the roads of Cherbourg (France) in the central English Channel. Measurements were also obtained in pore waters, in which ²¹⁰Po activities range between 1 and 20 mBq L⁻¹ and ²¹⁰Pb activities between 2.4 and 3.8 mBq L⁻¹, with highest activities in the topmost layer. These activities are higher than in seawater, suggesting that sediment act as a source of both ²¹⁰Po and ²¹⁰Pb for overlying water. The ²¹⁰Po profile in the pore waters is apparently correlated with those obtained for Fe, Mn and SO₄²⁻, suggesting an influence of early diagenetic processes on the ²¹⁰Po solid-liquid distribution. In the sediment, ²¹⁰Po is predominantly bound to organic matter or chromium reducible sulphides, and residuals (clay minerals and refractory oxides). Our results indicate that ²¹⁰Po is not significantly bound to AVS, i.e. acid volatile sulphides: bioturbation could play a role by the early redistribution of ²¹⁰Po bound to acid volatile sulphides in the sediment. ²¹⁰Po, ²¹⁰Pb and Pb exhibit differences in terms of distribution, probably due to a different mode of penetration in the sediment. This work provides information on solid and liquid distribution of ²¹⁰Po and ²¹⁰Pb in marine sediment. These data are very scarce in the litterature.     

Water Quality in the Near Coastal Waters of the Gulf of Mexico Affected by Hurricane Katrina: Before and After the Storm

Water quality was assessed following Hurricane Katrina in the affected waters of Alabama, Mississippi, and Louisiana. Post-landfall water quality was compared to pre-hurricane conditions using indicators assessed by EPA’s National Coastal Assessment program and additional indicators of contaminants in water and pathogens. Water quality data collected after Hurricane Katrina suggest that the coastal waters affected by the storm exhibited higher salinity and concentrations of chlorophyll a, dissolved inorganic phosphorus, and total suspended solids following the storm compared to the previous 5-year averages. Higher bottom dissolved oxygen concentrations and light attenuation were also observed. Contaminant concentrations measured in the water column were very low or undetectable, as were the presence of pathogens. Overall water quality did not significantly differ from water quality assessed in the five years preceding the storm. Statistical analyses indicate that use of a probabilistic survey design is appropriate for making pre-storm and post storm comparisons for water quality condition on an areal basis. The information in this article has been funded wholly (or in part) by the U.S. Environmental Protection Agency. It has been subjected to review by the National Health and Environmental Effects Research Laboratory and approved for publication. Approval does not signify that the contents reflect the views of the Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. This is contribution number 1280 from the Gulf Ecology Division.     

Assessing the steady-state [·NO<Subscript>2</Subscript>] in environmental samples

Based on available literature data of [NO₂ ⁻], steady-state [·OH], and ·OH generation rate upon nitrate photolysis in environmental aqueous samples under sunlight, the steady-state [·NO₂], could be calculated. Interestingly, one to two orders of magnitude more ·NO₂ would be formed in photochemical processes in atmospheric water droplets compared to transfer from the gas phase. The relative importance of nitrite oxidation compared to nitrate photolysis as an ·NO₂ source would be higher in atmospheric than in surface waters. The calculated levels of ·NO₂ could lead to substantial transformation of phenol into nitrophenols in both atmospheric and surface waters.     

基于MODIS的烟台近海水体叶绿素浓度分布

利用实测光谱数据及水体叶绿素浓度数据建立了基于MODIS数据的叶绿素反演模型,并利用MODIS L1B数据对研究区的叶绿素浓度进行了反演。通过分析烟台近海水体叶绿素浓度分布得出,烟台近海水体叶绿素浓度由沿岸向海延伸,叶绿素的浓度逐渐增加;通过不同月份的叶绿素浓度分布状况发现,夏季水体叶绿素浓度含量最高,冬季最低。     

江苏某县乡镇饮用水中挥发性有机物的检测及其风险评价

在江苏某癌症高发县5个乡镇10个村进行布点取样,采集深层地下水与浅层地下水共计20个水样。采用吹扫捕集与气相色谱-质谱联用方法测定水样中14种挥发性有机物(VOCs),检出二氯甲烷、1,3-二氯丙烷、三氯甲烷、苯和四氯化碳5种VOCs,其质量浓度分别为0.14～1.71、ND～50.98、0.29～90.02、0.09～2.35、0.18～3.45μg/L。2个水样中的三氯甲烷和6个水样中四氯化碳超过《生活饮用水卫生标准》(GB 5749—2006)规定的限值。采用优化的美国环保局风险评价模型进行人体健康风险评价,其非致癌风险指数为0.000 7～0.072,致癌风险水平1.70×10-7～2.03×10-5,70%水样的致癌风险水平超过10-6水质监控值,2个浅层地下水的致癌风险水平较高。四氯化碳和三氯甲烷对非致癌风险指数和致癌风险水平贡献较大。     

垃圾堆体固有渗透与孔隙度协同演化特征实验研究

为探讨上覆载荷作用下垃圾堆体渗透特性的变化规律,采用自制的生活垃圾渗透率/孔隙度测试实验装置,研究了不同载荷、不同压实密度及不同含水率对垃圾堆体固有渗透率和孔隙度变化规律的影响,并构建了固有渗透率与孔隙度之间的协同表征模型。结果表明,压实密度与上覆载荷呈指数递增的变化形式;随着含水率的增大,垃圾固有渗透率显著降低;垃圾固有渗透率随孔隙度的减小呈现指数递减,传统K-C模型无法描述这一变化规律,而幂函数形式(κ=AnB)和线性形式(lg(κ)=a+blg(n))2种协同表征模型均与实验结果达到了良好的拟合效果,验证了2种模型的可靠性;随着模型尺度的增大,固有渗透率从10-15m2量级增加至10-12m2量级,孔隙度从0.378增加至0.685。     

Long-Term Effects on Soil of the Disposal of Olive Mill Waste Waters (OMW)

Disposal of untreated olive mill waste waters (OMW) is a serious environmental problem in many Mediterranean countries. The aim of this work was to assess whether changes in soil properties have occurred due to direct disposal of raw OMW on soil and in evaporation ponds, and to investigate the potential fate and transport of pollutants after olive oil production had ceased. The results clearly showed that uncontrolled OMW disposal is a significant source of pollution to surface soil and waters. Disposal of OMW on soil greatly increased electrical conductivity (EC), available phosphorous (P), exchangeable potassium (K) and magnesium (Mg), organic matter, polyphenols, total and inorganic nitrogen (N), and available micronutrients mainly in surface soil layers. The presence of a high content of clay and carbonates in soil act as barriers and prevent downward transport of pollutants. Residual levels of total carbon (C), polyphenols, total and inorganic N, exchangeable K⁺, available P, iron (Fe), and copper (Cu) were also elevated even 8 years after mill closure. The long term disposal of OMW highlights the need to establish soil quality standards for soil parameters in order to identify soils affected by the disposal of OMW.     

Pre-concentration of naturally occurring radionuclides and the determination of (212)Pb from fresh waters

A novel technique has been developed for determining the ²¹²Pb activity of fresh waters. This is of interest to environmental monitoring programmes that utilise gross α-activity methods to screen for anthropogenic radionuclides. The contribution from ²¹²Pb varies, and is difficult to experimentally measure due to its relatively short half-life (t_½ = 10.6 h) and low environmental activity (<0.1 Bq l⁻¹). The use of a three-stage technique that encompasses a unique form of pre-concentration, separation and analysis by liquid scintillation counting allows a lower detection limit of 0.006 Bq l⁻¹ with a chemical yield of 92.5 ± 5.6%. The measurement can be obtained within 7 h of sample collection, and is calculated using the radioactive decay of ²¹²Bi. Other naturally occurring radionuclides may also be extracted using the pre-concentration stage of the technique, with efficiencies above 90% at a range of pH values.     

江苏省近岸海域表层海水微塑料的组成与赋存特征

于2019年10月,对江苏省(连云港、盐城和南通3市)近岸海域6个站位进行了1个航次的表层海水微塑料采样,监测分析了微塑料的粒径、丰度和组分分布情况.结果表明,江苏省近岸海域表层海水中微塑料污染广泛存在,监测站位检出率100％.微塑料粒径分布为0.02～4.80 mm,微米级微塑料占比最高(总体粒径占比83.4％),6...     

海底管道在位状态调查实践

根据调查设备搭载器的不同,将海底管道在位状态调查方法归为船载、自治水下机器人搭载(AUV 搭载)和无人遥控潜水器搭载(ROV搭载)三类;在浅水段采用船载调查,在深水段采用AUV搭载调查,在此基础上进行重点关注区域筛选,开展ROV调查,最后进行整体评价和分析对比,这种^“(船载/AUV)+ROV^”组合模式很好地实现了多种调查方法的优势互补。实际上,采用AUV搭载进行海底管道在位状态调查在国内业界尚属首次。调查所取得的管道位置、埋深、周边障碍物的分布以及管道人工处理情况等成果,为后期开展管道维护工作提供了重要的基础数据。此次成功实践可为以后从浅水到深水的管道在位状态调查提供经验和借鉴。