天津地区沙尘天气与沙尘污染程度特征分析

针对天津地区沙尘天气过程环境空气中颗粒物的污染时空分布特征进行了系统分析。在分析我国沙尘发生频源区域分布、输送途径基础上,分析了天津地区特殊的地理位置及地处沙尘暴多发区下游,空气中颗粒物的污染特征,概述了沙尘天气对空气质量影响程度的年、季、月及日污染时空变化分布特征。建立了沙尘天气颗粒物与有效水平能见度乘幂指数相关方程,为沙尘污染程度的诊断提供了依据。     

Wind Characteristics of Mesquite Streets in the Northern Chihuahuan Desert, New Mexico, USA

Past research has shown that the most important areas for active sand movement in the northern part of the Chihuahuan Desert are mesquite-dominated desert ecosystems possessing sandy soil texture. The most active sand movement in the mesquite-dominated ecosystems has been shown to take place on elongated bare soil patches referred to as “streets”. Aerodynamic properties of mesquite streets eroded by wind should be included in explaining how mesquite streets are more emissive sand sources than surrounding desert land. To understand the effects of wind properties, we measured them at two flat mesquite sites having highly similar soil textures but very different configurations of mesquite. The differences in wind properties at the two sites were caused by differences of size, orientation, and porosity of the mesquite, along with the presence of mesquite coppice dunes (sand dunes stabilized by mesquites growing in the dune and on its surface) found only at one of the two sites. Wind direction, u_* (friction velocity), z₀ (aerodynamic roughness height) and D (zero plane displacement height) were estimated for 15-m tower and 3-m mast data. These aerodynamic data allowed us to distinguish five categories with differing potentials for sediment transport. Sediment transport for the five categories varied from unrestricted, free transport to virtually no transport caused by vegetation protection from wind forces. In addition, “steering” of winds below the level of the tops of mesquite bushes and coppice dunes allowed longer parallel wind durations and increased wind erosion for streets that aligned roughly SW–NE. U.S. Government right to retain a non-exclusive royalty-free licence in and to any copyright is acknowledged.     

我国四个大气背景点颗粒物浓度及其元素分布特征

选择全国由南至北的4个大气背景站(广东南岭、湖北神农架、山西庞泉沟和吉林长白山),于2013年分4个季度同步采集环境空气颗粒物PM10和PM2.5样品,采用微波消解电感耦合等离子体质谱法测定滤膜样品中60余种元素.结果表明,4个背景点PM2.5日均质量浓度平均值为17μg·m-3,PM10为29μg·m-3,低于《环境空气质量标准》(GB 3095—2012)规定的一级浓度限值.第一季度的PM10和PM2.5最高,除长白山第三季度高于第四季度之外,其他3个点位均呈现第二季度第四季度第三季度的趋势.PM2.5和PM10二者呈线性正相关,4个季度的PM2.5/PM10比值均小于0.5,第二、第三季度较高,而第一、第四季度较低.PM10和PM2.5中元素随季节变化不大,PM2.5含量在同一水平上低于PM10.Na、Mg、Al、S、K、Ca、Fe、Zn质量浓度在0.1—10μg·m-3之间,P、Ti、Mn、Ni、Cu、Ba、Pb质量浓度在10—100 ng·m-3之间,Cd、Co、Ge、Ga、Zr、Sr、V等质量浓度在0.01—10 ng·m-3之间.K、Al、Ca含量大于10%,S、Mg、Na、Fe、Zn、Pb、Mn含量大于1%,Cu、P、Ba、Ti量介于0.5%—1%,其他痕量元素含量所占比例小于0.5%.     

Enrichments of Trace Metals in Particulate Matter From the Southern East China Sea, North of Taiwan

This study investigates the distributions and enrichments of trace metals in suspended and sinking particulate matter from southern East China Sea (ECS) north of Taiwan during the period April 1992 to April 1993. According to these results, concentration of suspended particulate matter in the inner shelf of southern China Sea, the upwellinginfluenced shelf break, and in Kuroshio water are 1.30 (surface)-4.2 (bottom) mg1^-1, ca. 0.4 mg1^-1 and 0.1-0.2 mg1^-1, respectively, reflecting various influences of terrestrial inputs. A benthic nepheloid layer (BNL), apparently owing to resuspension of local and/or remote bottom sediments, formed over the shelf region. Temporal variations in trace metal contents and enrichments in suspended matter from the shelf region reflect the variation of metal inputs from Chinese rivers, particularly from the Changjiang runoff. the enriched metals are more likely to be derived from anthropogenic input, rather than from biological accumulation. in addition, a decrease in metal contents and an increase in salinity confirm the transport of suspended particulate metals from the East China Sea shelf to the open ocean. the feature of metal plume in the intermediate layer (550-800m) of Kuroshio water also verifies this occurrence. Moreover, the sinking particles collected from a sediment trap on the upper slope are relatively enriched in lithogenic matter and trace metals, suggesting the deposit of anthropogenic metals in the slope area.     

Enrichments of Trace Metals in Particulate Matter From the Southern East China Sea,North of Taiwan

Abstract

This study investigates the distributions and enrichments of trace metals in suspended and sinking particulate matter from southern East China Sea (ECS) north of Taiwan during the period April 1992 to April 1993. According to these results, concentration of suspended particulate matter in the inner shelf of southern China Sea, the upwellinginfluenced shelf break, and in Kuroshio water are 1.30 (surface)–4.2 (bottom) mg1^?1, ca. 0.4 mg1^?1 and 0.1–0.2 mg1^?1, respectively, reflecting various influences of terrestrial inputs. A benthic nepheloid layer (BNL), apparently owing to resuspension of local and/or remote bottom sediments, formed over the shelf region. Temporal variations in trace metal contents and enrichments in suspended matter from the shelf region reflect the variation of metal inputs from Chinese rivers, particularly from the Changjiang runoff. the enriched metals are more likely to be derived from anthropogenic input, rather than from biological accumulation. in addition, a decrease in metal contents and an increase in salinity confirm the transport of suspended particulate metals from the East China Sea shelf to the open ocean. the feature of metal plume in the intermediate layer (550–800m) of Kuroshio water also verifies this occurrence. Moreover, the sinking particles collected from a sediment trap on the upper slope are relatively enriched in lithogenic matter and trace metals, suggesting the deposit of anthropogenic metals in the slope area.     

干旱区绿洲灌漠土Cu、Zn和Pb的吸附解吸特征

土壤重金属吸附解吸是影响土壤系统中重金属移动性和归宿的主要过程,影响重金属的生物有效性以及重金属在食物链中的传递等.配制一系列不同浓度的重金属,灌漠土对重金属溶液进行吸附实验24 h以达到平衡,再用硝酸铵和乙酸铵进行解吸实验24 h以达到平衡.利用热力学吸附平衡法,对西北干旱区绿洲灌漠土重金属Cu、Ni和Pb的吸附解吸行为进行序批实验研究.实验结果表明:(1)灰漠土在常温下对铜、锌和铅重金属离子的吸附等温线符合Freundlich型吸附模式,灰漠土对重金属铜、锌和铅的吸附能力由强到弱的顺序为:铅,铜,锌.(2)硝酸铵和乙酸铵解吸重金属的量与灰漠土吸附重金属量呈现出线性正相关,乙酸铵解吸重金属的量比硝酸铵解吸重金属的量大,两种解吸剂对铜、锌和铅重金属离子的解吸能力由大到小的顺序都为:铜,锌,铅,说明了一般外源的铜、锌和铅进入土壤以后,铜和锌可能比铅容易向四周转移.(3)硝酸铵和乙酸铵的解吸率呈谷形曲线,开始时硝酸铵和乙酸铵解吸重金属量的百分比随灰漠土吸附重金属量的增加而减小,在吸附量达到某一特定值时,解吸率随吸附量的增加而增加.灰漠土对铜、锌和铅的吸附作用以专性吸附为主,被灰漠土吸附的铜、锌和铅重金属离子较难解吸.     

A sustainability assessment of a high-yield agroecosystem in Huantai County,China

Sustainable agricultural development is a perennial issue for agricultural researchers, government managers, and policy makers worldwide, but especially in developing countries. In China, farms in Shandong Province epitomize modern agriculture and play a vital role in providing food for the burgeoning population. However, Chinese agriculture is being challenged by declining resources and environmental deterioration resulting from modern farming practices. China must establish an efficient agricultural sustainability index (ASI) to evaluate agricultural conditions and offer recommendations for sustainable development. Here, we use Huantai County, Shandong Province to test a regionalscale ASI from social, economic and ecological factors that includes 11 sustainability indicators. To further evaluate the complex agroecosystem, we employed the analytic hierarchy process (AHP) and AMOEBA methods to assess agricultural sustainability from 1982 to 2003. The results show that environmental problems, especially groundwater depletion, are limiting regional sustainable development.     

Long-term trends of fine particulate matter and chemical composition in the Pearl River Delta Economic Zone (PRDEZ), China

Understanding the trends in PM_2.5 levels is essential for formulating clean air plans. This paper analyzes PM_2.5 data from various published sources for the years 2000 to 2010 in the Pearl River Delta Economic Zone (PRDEZ). The long-term variation in PM_2.5 mass concentration is analyzed. Results show that PM_2.5, organic carbon (OC), elemental carbon (EC), and SO42− show a similar trend, increasing before 2005 and then decreasing slightly. The annual average PM_2.5 concentration ranges from 49.1 μg·m⁻³ in 2000 to 64.3 μg·m⁻³ in 2010, with a peak of 84.1 μg·m⁻³ in 2004. None of these 11 years meets the new National Ambient Air Quality standard (NAAQS) for PM_2.5 (35 μg·m⁻³). Overall average concentrations of OC, EC, and SO42− are 13.0, 6.5, and 11.8 μg·m⁻³, respectively. NO3− and NH4+ respectively have concentrations of 1.5 μg·m⁻³ and 2.9 μg·m⁻³ in 2000 and 6.4 μg·m⁻³ and 5.3 μg·m⁻³ in 2010, with a statistically significant average annual trend of+ 0.2 μg·m⁻³·yr⁻¹ and+ 0.1 μg·m⁻³·yr⁻¹. In certain geographic regions, OC and EC contribute most of the PM_2.5, while in other regions secondary water-soluble ions are more important. In general, OC and SO42− are the dominant components of PM_2.5, contributing 20.6% and 18.6%, respectively. These results provide, for the first time, a better understanding of the long-term PM_2.5 characteristics and trends, on a species-by-species basis, in the PRDEZ. The results indicate that PM_2.5 abatement needs to prioritize secondary species.     

西南某矿区家庭灰尘中重金属的暴露及其健康风险评价

家庭灰尘是人群居住场所的重要环境介质,人群可通过吸入、摄食及皮肤接触等途径摄入灰尘中的污染物,对健康造成一定的损伤。为探索我国西南某矿区周边村庄室内重金属的污染对人群健康的潜在风险,采用2014年3月对我国西南某矿区周边村庄室内灰尘中重金属污染水平调查的数据,结合美国EPA健康风险评价模型对人群健康风险进行分析。结果表明:人群非致癌风险和致癌风险暴露剂量均表现为儿童>成人男性>成人女性,呈现手-口摄食途径>皮肤接触途径>吸入途径,其中儿童、成人男性和成人女性手-口摄食暴露途径占总暴露剂量的98.16%、55.61%和51.5%;儿童以Pb、Cr的暴露为主,成人以Cr的暴露为主;家庭灰尘中单种重金属元素和多途径叠加的非致癌风险在8.81E-03~1.24E-02之间,均小于1,其中儿童以Pb的非致癌风险为主,经手-口摄食暴露占总风险的40%;致癌风险在4.19E-05~3.35E-04之间;A、B、C村儿童的致癌风险均高于US EPA所推荐的可接受水平10-4,其暴露剂量和健康风险均为成人男性和成人女性的5~6倍,且以Cr通过手-口摄食暴露产生的风险最大,占总风险的93%左右。     

云南省会泽县农田土壤中全氟化合物污染特征研究

为探究云南省会泽县农田土壤中全氟化合物(perfluorinated compounds,PFCs)的污染特征及其潜在来源,2015年6月采集云南省会泽县农田土壤42份,利用高效液相色谱-串联质谱仪(HPLC-MS/MS)分析了11种PFCs的含量水平。结果表明,云南省会泽县农田土壤中全氟己酸(perfluorohexanoic acid,PFHx A)、全氟庚酸(perfluoroheptanoic acid,PFHp A)和全氟己烷磺酸(perfluorohexane sulfonate,PFHx S)均未检出,其余8种PFCs(ΣPFCs)的平均含量水平为0.392 ng·g-1,含量范围为0.298~0.998ng·g-1。全氟辛酸(perfluorooctanoic acid,PFOA)和全氟辛烷磺酸(perfluorooctane sulfonate,PFOS)是最主要的PFCs,相对百分含量范围为45.93%~81.86%,其平均含量水平分别为0.116 ng·g-1和0.120 ng·g-1。与国内其他地区土壤中PFCs的含量水平相比,云南省会泽县农田土壤中PFCs含量水平低于上海,与广州、深圳、东莞、安徽、中国东部农村等地区土壤中PFCs的含量相当。主成分分析结果表明,以全氟癸酸(perfluorodecanoic acid,PFDA)、全氟辛烷磺酸(PFOS)和全氟十三酸(perfluorotridecanoic acid,PFTr DA)为主要标志物的2个主成分可以解释云南省会泽县农田土壤中73%的ΣPFCs。工业活动、大气沉降及长距离传输为云南省会泽县农田土壤中PFCs的主要来源。