Chemical Tracking and Marine Environmental Impact of Ocean Disposal of Calcium Carbonate Residue in the North Yellow Sea

The objective of this study is to determine the sedimentation rate and dispersion area of calcium carbonate residue dumped at sea and the impact to marine environment of dumping by a laboratory simulation experiment; chemical tracking in the field with the help of acoustic and optical tracking; and a comparative study of baseline conditions and marine environmental impact after dumping. Turbidity, pH and phosphate are selected as the chemical tracers to be monitored.

Results show that in the dumping area of 15 square miles with water depth of 50 m, if 217 t calcium carbonate residue is dumped (spot dumping) in the presence of a pycnocline with a current velocity of 60 cm/s (close to the maximum) the maximum dispersion distance of the calcium carbonate residue plume front is less than 2100 m; the dispersion area is less than 0.56 km²; and the maximum dispersion time is about 60 min when the turbidity and pH in the whole dispersion area return to background level. Therefore, the ocean disposal of calcium carbonate residue is feasible.     

Response of activity and community composition of nitrite-oxidizing bacteria to partial substitution of chemical fertilizer by organic fertilizer

Environmental Science and Pollution Research - Nitrite oxidation as the second step of nitrification can become the determining step in disturbed soil systems. As a beneficial fertilization...     

Chemical Tracking and Marine Environmental Impact of Ocean Disposal of Calcium Carbonate Residue in the North Yellow Sea

The objective of this study is to determine the sedimentation rate and dispersion area of calcium carbonate residue dumped at sea and the impact to marine environment of dumping by a laboratory simulation experiment; chemical tracking in the field with the help of acoustic and optical tracking; and a comparative study of baseline conditions and marine environmental impact after dumping. Turbidity, pH and phosphate are selected as the chemical tracers to be monitored.

Results show that in the dumping area of 15 square miles with water depth of 50 m, if 217 t calcium carbonate residue is dumped (spot dumping) in the presence of a pycnocline with a current velocity of 60 cm/s (close to the maximum) the maximum dispersion distance of the calcium carbonate residue plume front is less than 2100 m; the dispersion area is less than 0.56 km²; and the maximum dispersion time is about 60 min when the turbidity and pH in the whole dispersion area return to background level. Therefore, the ocean disposal of calcium carbonate residue is feasible.     

膜法处理含油废水研究进展

介绍了含油废水的来源、危害及其一般的处理方法,概述了国内外处理含油废水的膜分离技术——微滤、超滤、反渗透及膜法联合处理工艺的研究现状。对膜污染与预防问题进行了探讨,指出了膜法联合处理工艺是今后处理含油废水的研究方向,而研制抗污染、净化效果好、成本低廉的新型功能有机高分子过滤吸附材料也是含油废水处理领域的一项重要工作。     

云南金厂金矿床铬绢云母系列分类与地质意义

通过 5 7个电子探针分析、1个湿法化学全分析、3个中子活化分析、1个差热分析和 3个粉晶X射线衍射分析 ,首次将金厂金矿床铬绢云母系列划分为二个矿物类十个矿物种和三个生成世代 ,并总结出其成因矿物学特征 ,提出铬绢云母系列的生成与金矿的形成关系密切 ,铬绢云母系列是该区找金的重要标志     

疏浚物对栉孔扇贝急性致死量的实验研究

本文探讨实验室室条件下疏浚物对栉孔扇贝９６ｈ半致死浓度以及试验条件的筛选，实验结果表明，疏浚物粒径小于６３μｍ，海水中悬浮物浓度为１０％，水温（２０±１）℃，ｐＨ８．０－８．３，盐度２９－３０，充氧条件下，栉孔扇贝９６ｈ内的死亡率为６３％。     

成都饮食中全氟化合物的污染特征及健康风险评估

为了解成都市居民通过饮食暴露于全氟化合物(Perfluoroalkyl Substances, PFASs)的情况,本研究通过调查统计成都市居民的主要饮食情况,选取米、蔬菜、牛奶、鸡蛋、鱼和猪肉6类饮食为研究对象,采用超高效液相色谱-串联质谱法对样品中17种PFASs进行检测.结果显示,所有饮食中均检出PFASs,说明PFASs在饮食中普遍存在.鸡蛋中的∑PFASs含量最高,达(155±25.4) ng·g~(-1)(湿重,下同);白菜的∑PFASs含量最低,仅为(0.101±0.026) ng·g~(-1).大部分样品中以全氟辛烷羧酸(Perfluroroocantanoic Acid,PFOA)为主,其次为短碳链的全氟羧酸(Perfluoroalkyl Acids,PFCAs).其中,鸡蛋蛋黄中∑PFASs的含量为(600.0±98.6) ng·g~(-1),远高于蛋清中的含量(0.606±0.101) ng·g~(-1),且蛋黄中主要为全氟辛烷磺酸(Perfluorooctane Sulfonate,PFOS)(98.1%).通过风险评估可以得出,成都市居民对PFOS和PFOA的日摄入量分为85.6 ng·kg~(-1)·d~(-1)和4.38 ng·kg~(-1)·d~(-1),低于欧盟食品安全局推荐的每日最大摄入量,不会对成都市居民造成即时伤害.     

农村生活污水治理问题及优化措施

为提升农村经济水平,解决农村水环境问题,介绍了农村生活污水治理模式,包括城乡统一治理模式、村落集中处理模式、农户分散处理模式.指出了农村生活污水治理存在的问题:缺乏顶层设计,缺乏市场化投入机制与运营机制,农民群体参与不足.提出了农村生活污水治理优化建议:基于顶层设计建立长效管理机制,通过市场机制开展运行维护与管理,基于...     

Unraveling SO2-tolerant mechanism over Fe2（SO4）3/TiO2 catalysts for NOx reduction

Developing low-temperature SO₂-tolerant catalysts for the selective catalytic reduction of NO_x is still a challenging task. The sulfation of active metal oxides and deposition of ammonium bisulfate deactivate catalysts, due to the difficult decomposition of the as-formed sulfate species at low temperatures（<300 °C）. In recent years, metal sulfate catalysts have attracted increasing attention owing to their good catalytic activity and strong SO₂ tolerance at hi...     

基于监测数据的边坡参数统计特征及可靠度更新∗

掌握详细的边坡岩土体参数信息是进行边坡加固与风险评估的重要前提。目前大多采用马尔可夫链蒙特卡洛模拟方法基于现场或室内试验数据进行不确定性参数统计信息及边坡可靠度更新。然而,该方法存在计算量大、计算结果不易收敛和难以解决高维边坡不确定性参数统计特征及可靠度更新等问题。本文基于粒子群优化反向传播神经网络算法建立边坡位移代理模型优化计算过程,提出了改进的基于子集模拟的贝叶斯更新方法,进而基于边坡变形监测数据进行参数统计特征及可靠度更新。最后,将提出方法应用到长春西客站深基坑边坡工程。 结果表明：提出方法能够融合有限的场地信息有效地更新边坡岩土体参数统计特征,推断其后验概率密度函数,进而更新边坡失效概率。利用更新的土体参数计算的边坡位移与实测数据吻合,验证了提出方法的适用性和有效性。另外融合监测数据进行贝叶斯更新之后,虽然土体参数的不确定性明显降低,但是边坡失效概率受外界气温、 监测点位置及数据量值的影响会增大。