Heavy metals in coastal wetland sediments of the Pearl River Estuary, China

Sediment quality in coastal wetlands of the Pearl River Estuary was concerned since the wetlands were used for land reclamation, aquaculture and wildlife protection, and meanwhile served as one of the main ultimate sinks for large amount of heavy metals discharged from the rapidly developing Pearl River Delta. Total concentrations of heavy metal, such as Zn, Ni, Cr, Cu, Pb, and Cd, and their chemical speciation were investigated. Results showed that the sediments were significantly contaminated by Cd, Zn and Ni with concentration ranges of 2.79-4.65, 239.4-345.7 and 24.8-122.1mg/kg, respectively. A major portion (34.6-46.8%) of Pb, Cd, and Zn was strongly associated with exchangeable fractions, while Cu, Ni and Cr were predominantly associated with organic fractions, residual, and Fe-Mn oxide. Cd and Zn would be the main potential risk and the sediment quality is no longer meeting the demand of the current wetland utilization strategies.     

Analysis of the effects diclofenac has on Japanese medaka (Oryzias latipes) using real-time PCR

The expression levels of cytochrome P450 1A, p53 and vitellogenin were investigated in three different tissues of male medaka fish after exposure to diclofenac that is one of the main concerns among pharmaceuticals frequently found in sewage treatment plant (STP) effluents. The results showed that cytochrome P450 1A, p53 and vitellogenin were highly expressed in tissue-specific gene expression patterns after exposure to 8 mg/l and 1 μg/l of diclofenac. These elevated expression levels of three biomarkers suggested that diclofenac has potential to cause cellular toxicity, p53-related genotoxicity and estrogenic effects. It is also noteworthy that diclofenac has the potential to cause these effects even at an environmentally relevant concentration of diclofenac, 1 μg/l.     

Nutrient Dynamics in Jiaozhou Bay

Three cruises were carried out in Jiaozhou Bay (JZB) in the neap tide in October 2002 (fall) and in both neap and spring tides in May 2003 (spring) to understand the relative importance of external nutrient inputs versus physical transport and internal biogeochemical processes. Nutrients (, , , , silicic acid, total dissolved nitrogen (TDN) and phosphorus (TDP), dissolved organic nitrogen (DON) and phosphorus (DOP)) were measured. The concentrations of nutrients were higher in the northern part than in the southern part. High concentrations of and DON in JZB demonstrated the anthropogenic input. Ambient nutrient ratios indicated that the potential limiting nutrients for phytoplankton growth were silicon, and then phosphorus. Nutrients showed an obvious tidal effect with low values at flood tide and high values at ebb tide. Nutrient elements were transported into JZB in the north and output in the south (i.e., into the Yellow Sea), which varied with season, tidal cycle and investigation sites. Water exchange between JZB and the Yellow Sea exports , and DON out of JZB, while it inputs , silicic acid and DOP into JZB. Nutrient budgets demonstrate that riverine input and wastewater discharge are major sources of nutrients, while residual flow is of minor importance in JZB ecosystem. JZB is a sink for the nutrient elements we studied except for DON. Stoichiometric calculations demonstrate that JZB is a net autotrophic system.     

Dynamic response of the scenic beauty value of different forests to various thinning intensities in central eastern China

Forest management has a significant influence on the preferences of people for forest landscapes. This study sought to evaluate the dynamic effects of thinning intensities on the landscape value of forests over time. Five typical stands in Wuxiangsi National Forest Park in Nanjing&facet-content-type=ReferenceWorkEntry&sortOrder=relevance' class='reference-link webtrekk-track' gaCategory="internal-link" gaLabel="Nanjing" gaAction="reference keyword">Nanjing, China, were subjected to a thinning experiment designed with four intensities: unthinned, light thinning, moderate thinning, and heavy thinning. People’s preferences for landscape photographs taken in plots under various thinning intensities were assessed through scenic beauty estimation (SBE) at 2 and 5 years after thinning. The differences in scenic beauty value between different thinning intensities were then analyzed with a paired samples t test for the two periods. The results indicated that the landscape value of all of the thinned plots significantly exceeded that of the unthinned plots 2 years after thinning (p?相似文献   

兽药类环境内分泌干扰效应及评价研究进展

兽药在保障动物健康、提高畜禽产品质量尤其在畜牧业集约化发展等方面起着至关重要的作用,然而兽药和饲料添加剂的大量使用成为生态环境污染和人体健康损害的一个重要因素。研究表明许多抗生素类和激素类兽药是典型的环境内分泌干扰物,通过多种方式干扰生物体雄激素、雌激素、甲状腺激素等内分泌过程,产生内分泌干扰效应。本文介绍了典型兽药的污染现状及其内分泌干扰效应研究最新进展;以环境内分泌干扰物的最新研究方法为基础,较全面地评述了可用于兽药类内分泌干扰物的快速筛选、检测及评价方法,并对该领域未来研究提出了展望和建议,以期为环境和农业等管理部门制定兽药的使用、排放、管理政策提供科学依据。     

Chemical properties of dissolved organic matter derived from sugarcane rind and the impacts on copper adsorption onto red soil

Dissolved organic matter (DOM), as the most active organic carbon in the soil, has a coherent affinity with heavy metals from inherent and exogenous sources. Although the important roles of DOM in the adsorption of heavy metals in soil have previously been demonstrated, the heterogeneity and variability of the chemical constitution of DOM impede the investigation of its effects on heavy metal adsorption onto soil under natural conditions. Fresh DOM (FDOM) and degraded DOM (DDOM) from sugarcane rind were prepared, and their chemical properties were measured by Fourier-transform infrared spectrometry (FTIR), excitation-emission matrix (EEM) fluorescence spectroscopes, nuclear magnetic resonance (NMR), and molecular weight distribution (MWD). They were also used in batch experiments to evaluate their effects on the adsorption of Cu(II) onto farmland red soil. Based on our results, the chemical structure and composition of DDOM greatly varied; compared with FDOM, the C/O ratio (from 24.0 to 9.6%) and fluorescence index (FI) (from 1.4 to 1.0) decreased, and high molecular weight (>10 kDa) compounds increased from 23.18 to 70.51%, while low molecular weight (<3 kDa) compounds decreased from 56.13 to 12.13%; aromaticity and humification degree were markedly enhanced. The discrepancy of FDOM and DDOM in terms of chemical properties greatly influenced Cu(II) adsorption onto red soil by affecting DOM-Cu(II) complex capacity. The FDOM inhibited the adsorption of Cu(II), while DDOM promoted adsorption, which was significantly influenced by soil pH. Maximum adsorption capacity (Q _m) was 0.92 and 5.76 mg g^?1 in the presence of FDOM and DDOM, respectively. The adsorption process with DDOM could be better described by the Langmuir model, while that with FDOM was better described by the Freundlich model. The impacts caused by the dynamic changes of the chemical properties of DOM under natural conditions should therefore be considered in the risk assessment and remediation of soils contaminated with heavy metals.     

The impact of airborne particulate matter on pediatric hospital admissions for pneumonia among children in Jinan,China: A case-crossover study

This study aims to examine the effect of short-term changes in the concentration of particulate matter of diameter ≤2.5 µm (PM_2.5) and ≤10 µm (PM₁₀) on pediatric hospital admissions for pneumonia in Jinan, China. It explores confoundings factors of weather, season, and chemical pollutants. Information on pediatric hospital admissions for pneumonia in 2014 was extracted from the database of Jinan Qilu Hospital. The relative risk of pediatric hospital admissions for pneumonia was assessed using a case-crossover approach, controlling weather variables, day of the week, and seasonality. The single-pollutant model demonstrated that increased risk of pediatric hospital admissions for pneumonia was significantly associated with elevated PM_2.5 concentrations the day before hospital admission and elevated PM₁₀ concentrations 2 days before hospital admission. An increment of 10 μg/m³ in PM_2.5 and PM₁₀ was correlated with a 6% (95% CI 1.02–-1.10) and 4% (95% CI 1.00–1.08) rise in number of admissions for pneumonia, respectively. In two pollutant models, PM_2.5 and PM₁₀ remained significant after inclusion of sulfur dioxide or nitrogen dioxide but not carbon monoxide. This study demonstrated that short-term exposure to atmospheric particulate matter (PM_2.5/PM₁₀) may be an important determinant of pediatric hospital admissions for pneumonia in Jinan, China.

Implications: This study demonstrated that short-term exposure to atmospheric particulate matter (PM_2.5/PM₁₀) may be an important determinant of pediatric hospital admissions for pneumonia in Jinan, China, and suggested the relevance of pollutant exposure levels and their effects. As a specific group, children are sensitive to airborne particulate matter. This study estimated the short-term effects attribute to other air pollutants to provide references for relevant studies.     

酶抑制法检测蔬菜中的有机磷农药

对新型酶抑制检测蔬菜中有机磷农药残留量的方法进行了研究,介绍了胆碱酯酶的提取、纯化方法,以及用粗酶和纯酶检测蔬菜中有机磷农药残留量的测定效果,确定了最佳实验条件。对样品的预处理方法进行了改进,得出该法的检测限为1mg／L,对甲基对硫磷等几种常用农药的加标回收率为90．4％～112％,相对标准偏差为1．06％～9．83％,表明三项评价指标均符合全国农药残留科研协作组对农药残留分析方法的基本要求。     

多元回归和BP人工神经网络模型对混合厌氧消化产气量的预测研究

在中温且控制pH值条件下,对脂肪类单基质和城市污水厂剩余污泥进行混合厌氧消化试验。基于多元回归原理和BP人工神经网络原理,对其建立产气量预测模型。由实验数据计算得出:两个阶段多元回归模型的预测平均准确率分别为75.69%和79.29%;BP神经网络模型的预测平均准确率为79.05%。通过对比两种模型的预测结果可知,两种模型都有较高的预测准确率,但BP模型的预测准确率更高,更适用于混合厌氧消化产气量预测。     

宁东能源化工基地工业固体废物综合利用现状分析、预测及建议

宁东能源化工基地目前以及将来都是宁夏回族自治区工业固体废物主要产生源,因此做好宁东能源基地工业固体废物污染防治工作就相当于解决了宁夏地区大部分工业固体废物问题。通过对基地在工业固体废物方面存在的问题进行剖析,提出宁东能源化工基地固体废物污染防治对策,旨在为减少宁东基地工业固体废物的产生量,提高工业固体废物的综合利用率。做好工业固体废物贮存、处置工作,提供科学指导,保证基地的高水平建设,为可持续发展提供科学依据。