Background metal levels determination in bivalves – quality assessment of the European Water Framework Directive

Background levels of metals (Ag, Cd, Cu, Cr, Hg, Ni, Pb and Zn) in biomonitors (Mytilus galloprovincialis mussels and Crassostrea gigas oysters), in estuarine waters within the Basque Country (south-east Bay of Biscay) are estimated using non-parametric statistical tools and data are presented graphically, with the aim of being used in assessing the ecological status, within the European Water Framework Directive (WFD). The basis for this study was the statistical analysis of data compiled from monitoring programmes undertaken along the Basque coast, between 1990 and 2008. For this analysis, a heuristic method was adapted and used. Results showed different metal background ranges throughout the year for both mussels and oysters. Values corresponding to the upper limit of the background range (i.e. value of the upper whisker of the box-plot) are proposed as the ‘high/good’ status boundary, according to the WFD.     

Spatial distribution of copper in relation to recreational boating in a California shallow-water basin

The overall effect of the number of boats on the copper (Cu) levels in the water column and sediment, along with their spatial variability within Shelter Island Yacht Basin (SIYB), San Diego Bay, California was examined. We identified a horizontal gradient of increasing dissolved Cu and Cu in sediment from outside to the head of SIYB which was coincident with the increasing number of boats. Spatial models of Cu distribution in water and sediment indicated the presence of ‘hotspots’ of Cu concentration. From outside to the head of SIYB, dissolved Cu ranged from 1.3 μ g L^?1 to 14.6 μ g L^?1 in surface water, and 2.0 μ g L^?1 to 10.2 μ g L^?1 in bottom water. Cu in sediment exceeded the Effect Range Low of 34 mg kg^?1 (i.e. where adverse effects to fauna may occur), with a peak concentration of 442 mg kg^?1 at the head of the basin. Free Cu⁺⁺ in surface water was several orders of magnitude higher than in sediment porewater. High-resolution data of Cu species together with probability maps presented in this paper will allow managers to easily visualise and localise areas of impaired quality and to prioritise which areas should be targeted to improve Cu-related conditions.     

Trace metals in fish of economic interest from the west of Alexandria,Egypt

The concentration of some heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, and Zn) in the muscle, liver, and gills in eight fish species, Caranx crysos, Euthynnus alleferatus, Scomberomorus commerson, Sphyraena viridensis, Sargus sargus, Siganus rivulatus, Mugil species, and Sardinella aurita were collected seasonally from the Mediterranean Sea in the region of Alexandria. The highest concentrations of Cd, Cu, Fe, and Zn were measured in liver tissue, while gill tissue yielded the highest concentrations of Mn, Ni, and Pb. Muscle is the organ of poor accumulation factor for all metals under investigation. Concentration of cadmium in muscle in Mugil species exceeds the permissible limit in summer, while Siganus rivulatus exceeds it in the summer and autumn seasons. On the other hand, copper, nickel, lead, and zinc are still much lower than the permissible levels. The metal pollution index (MPI) for metals was studied, revealing that Siganus rivulatus, Mugil species and Sardinella aurita had the highest MPI. Provisional tolerable daily intake (PTDI) indicates that the concentration levels of Cd, Cu, Fe, Mn, Ni, Pb, and Zn in the muscle of all fish species under investigation are much lower than recommended PTDI values, and accordingly there is no risk for the human consumption of these fish species.     

Public sector perspectives and policy implications for the Pitons Management Area World Heritage Site,St. Lucia

St. Lucia faces numerous challenges associated with striking a balance between its economic and conservation goals with respect to the Pitons Management Area (PMA) World Heritage Site. Among the various stakeholders, the public sector, which largely constitutes the administrative authorities representing the general public, plays an instrumental role in site management. They are primarily responsible for policy formulation as well as the provision of fiscal incentives and funds to assist in the maintenance of the site. Based on a qualitative inquiry approach, this study explored the perspectives of key persons among pertinent public and non-profit organizations. Semi-structured interviews were conducted among local and national representatives from the public sector. Results revealed that the designation of the PMA as a World Heritage Site has presented both opportunities and challenges to the management of the site. Findings strongly indicate that the integrity and sustainability of the site is at stake due to a lack of commitment, coordination and political will in the public sector.     

三峡水库香溪河库湾冬季甲藻水华生消机理初探

2010年1—2月在香溪河库湾上、中、下游各选取1个监测点对水体环境因子及藻类进行监测,对水温、营养盐含量等进行分析,探讨香溪河库湾冬季甲藻水华的生消机理. 结果表明:2010年冬季,香溪河库湾末端暴发了甲藻水华,持续44 d,优势藻种为拟多甲藻(Peridiniopsis sp.),最高细胞密度达到11.8×106 L-1;适宜的水温、充足的营养盐以及良好的光照、弱分层水体是香溪河库湾冬季甲藻水华暴发的主要原因;Zmix/Zeu〔Zmix(混合层深度)与Zeu(真光层深度)之比〕在2~3之间时有利于甲藻生长;库湾中下游因水体掺混强烈而在冬季未暴发水华;后期水体分层状态的加强及Zmix/Zeu的减小是甲藻水华消失的主要原因.      

Interspecific association among main plant species in the unstable slope with high-frequency debris flow北大核心CSCD

To determine the characteristics of vegetation community structure and the relationship between species in the frequent watersheds of debris flow in fragile ecological environments, based on sample survey and 2 × 2 joint table techniques, we used analysis of variance test, χ2 test, Jaccard index, Pearson correlation coefficient, and Spearman's rank correlation coefficient test to study the main plant species correlations in the stable zone, instable zone, and deposit zone of the unstable slope. The analysis of variance test showed that all 45 species pairs had a significant negative correlation in the stable zone and instable zone, whereas there was no significant negative correlation in the deposit zone, which showed that the species had an independent distribution trend. The results from the different tests showed that there were 1 pair, 4 pairs, and 4 pairs from the stable zone, instable zone, and deposit zone, respectively, which had significant interspecific association under the χ2 test and the ratios of positive correlation pairs to negative correlation pairs were 0.55, 0.67, and 0.67 in the stable zone, instable zone, and deposit zone, respectively. There were 8 pairs, 5 pairs, and 5 pairs from the stable zone, instable zone, and deposit zone, respectively, which had significant interspecific association from the Pearson correlation analysis test, and the ratios of positive correlation pairs to negative correlation pairs were 0.36, 0.45, and 0.45 in the stable zone, instable zone, and deposit zone, respectively. There were 10 pairs, 6 pairs, and 9 pairs from the stable zone, instable zone, and deposit zone, respectively, which had significant interspecific association from the Spearman's rank correlation analysis test and the ratios of positive correlation pairs to negative correlation pairs were 0.5, 0.55, and 0.6 in the stable zone, instable zone, and deposit zone, respectively. The three test results showed general similarities but there were some differences. Most species pairs did not reach a significant level in the three zones and the number of negatively related species was more than the number of positively related species. In brief, this loose interspecific relationship indicates that the entire plant community was not stable, and the interspecific relationships among species are susceptible to environmental interference in the ecologically fragile areas of the debris flow basin. Therefore, rational selection and configuration of species should be applied to promote community structure development and ecological environmental improvement in vegetation restoration process areas with high-frequency debris flow. © 2018 Science Press. All rights reserved.     

乡村路网对三峡库区社区水平森林结构的影响

道路作为人为扰动介质被认为是短时空尺度森林景观演化或用途转换的主要驱动力之一,体现为明显的“通道-阻隔”效应。论文以重庆市石柱县西沱镇为例,以3期遥感影像和调研数据为基础,利用ArcGIS的缓冲叠加功能,基于路网动态变化角度,从类型、林龄、起源等主要森林结构方面分析路网变化对森林结构变化的影响。结果表明：1）研究区道路数量先增加后减少,道路质量以等外公路和村级公路的改善为主。2）道路对森林景观干扰性明显。森林从类型、起源、林龄三方面在道路缓冲区内的破碎度均高于非缓冲区内的破碎度。1992—2002年及2002—2014年两个时期相比,前一时期其他灌木林、幼龄林以及萌生林大幅减少,基本表现为道路缓冲区内减少量大于非缓冲区内减少量。后一时期乔木林、中龄林以及萌生林有所增加,其他灌木林和成熟林轻微减少,其中,乔木林在道路缓冲区内增加量大于非缓冲区内增加量,中龄林及萌生林则表现为道路缓冲区内增加量弱于非缓冲区内增加量。3）道路影响域范围内,在无政策性干预条件下,道路的增加和质量的提高很大程度上导致森林景观的退化,低级路段的消失则有助于森林景观的恢复。     

有机质对三峡库区消落区沉积物磷释放的影响

以三峡库区丰都消落区沉积物为研究对象,通过分析沉积物中磷的赋存形态,以及去除轻组有机质沉积物和沉积物矿物质对磷的吸附等温曲线,揭示了磷的赋存形态及释放与有机质的关系. 结果表明:消落区本底土壤较沉积物w(总磷),w(有机磷)及w(活性磷)更高,首次覆水时更具潜在释磷风险,夏季出露期有利于沉积物有机质和有机磷积累,沉积物有机质矿化分解对磷释放起促进作用,沉积物中w(有机质)与w(有机磷)呈显著正相关,与w(无机磷)呈负相关.      

疏浚对梅粱湾表层沉积物重金属赋存形态及其生物毒性的影响

选择太湖梅梁湾未疏浚、疏浚后1周和疏浚后半年的表层沉积物为研究对象,测定其中重金属的含量及其不同赋存形态所占比例,开展沉积物间隙水中重金属毒性试验,据此探讨疏浚对沉积物中重金属含量及其赋存形态所占比例和生物毒性的影响. 结果表明:太湖梅梁湾调查区未疏浚沉积物重金属含量明显高于疏浚区,重金属的生物毒性占沉积物综合毒性的25%～35%. 疏浚后1周沉积物重金属含量急剧降低32%～51%,但对重金属生物毒性影响较大的吸附态及碳酸盐结合态重金属比例由未疏浚时的未检出或含量极低增加到40%～83%,生物毒性相应增加17%～38%;疏浚后半年,沉积物中重金属的总量略有回升,吸附态及碳酸盐结合态重金属比例下降,生物毒性下降并低于未疏浚时水平.