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1.
In Italy, the incapability of the State to implement a national strategy for the sustainable development of coastal areas lead the regional authorities to adopt integrated coastal zone management plans. These initiatives are often relevant, correcting the defiency of the national legislation, but do not assure the implementation of a coherent littoral policy. Thereby, it is to be hoped that the recent developments in international law—and particularly the Mediterranean protocol on integrated coastal zone management recently adopted—will compel the Italian State to make a positive commitment to coastal protection.  相似文献   

2.
The high consumption of crabs (Ucides cordatus) stimulated interest in the present study on the northern coast of Brazil, which encompasses a preserved area of mangrove forest. The objective was to describe and quantify the transfer of metals from the muddy sediments to the leaves of the Rhizophora mangle, and thence the crabs and humans. The samples were collected along two transects, while samples of hair were obtained from local habitants. The pH, interstitial salinity, Eh (mV) were measured, the granulometry and mineralogical and multi-element chemical analyses were run, and the organic material determined. The sediments are silty-clayey, composed of quartz, kaolinite, iron oxides, and illite, as well as smaller portions of smectite, pyrite, halite, and high levels of SiO2 (56.5 %), Al2O3 (18.5 %), and Fe2O3 (7 %). The elements Zn, Sr, As, and Zr are concentrated in the leaves, while the bioaccumulation of Zn, Se, Sr, and As was recorded in the crabs, of which, Se is the most concentrated in the tissue of the muscles and the hepatopancreas. The concentrations of nutrient and toxic elements were similar in all age groups (hair samples), with only Hg presenting an increasing concentration between infants and adults. The highest rates of transfer were recorded for the elements Zn and Se in the crabs and Hg in leaves and hair. The accumulation of metals in the leaves and crabs reflects the chemical composition of the sediments and low rates of sediment-vegetation-crab transfer, with the exception of Hg, which accumulated in the hair.  相似文献   

3.
Now, there is a decreasing trend for the prevalence rate of Kaschin–Beck disease (KBD) in most parts of China, but the disease is still active and severe in the Tibetan Plateau for some reason. To further explore the role of selenium in the occurrence of KBD, We collected samples including drinking water, cultivated topsoil, Highland Barley grains, and tsamba in Rangtang County and Aba County, Sichuan Province and determined concentrations of selenium by Hydride Generation Atomic Fluorescence Spectrometry. Levels of selenium in the environment were analyzed in detail. Selenium in the soil–plant–food system and their relationship with prevalence rate of KBD were also discussed. The results indicate: (a) the levels of environmental selenium are very low and the study area belongs to a selenium-deficient ecological landscape; (b) the KBD becomes much more severe with decreasing environmental selenium under the selenium-deficient condition. Namely, the lower the environmental selenium is, the more severe the disease is; (c) soil selenium deficiency plays a critical role for the prevalence of local KBD, and more factors inducing selenium deficiency should be more concerned in the future.  相似文献   

4.
Large rivers often present a river–lakedelta system, with a wide range of temporal and spatial scales of the flow due to the combined effects of human activities and various natural factors, e.g., river discharge, tides, climatic variability, droughts, floods. Numerical models that allow for simulating the flow in these river–lakedelta systems are essential to study them and predict their evolution under the impact of various forcings. This is because they provide information that cannot be easily measured with sufficient temporal and spatial detail. In this study, we combine one-dimensional sectional-averaged (1D) and two-dimensional depth-averaged (2D) models, in the framework of the finite element model SLIM, to simulate the flow in the Mahakam river–lakedelta system (Indonesia). The 1D model representing the Mahakam River and four tributaries is coupled to the 2D unstructured mesh model implemented on the Mahakam Delta, the adjacent Makassar Strait, and three lakes in the central part of the river catchment. Using observations of water elevation at five stations, the bottom friction for river and tributaries, lakes, delta, and adjacent coastal zone is calibrated. Next, the model is validated using another period of observations of water elevation, flow velocity, and water discharge at various stations. Several criteria are implemented to assess the quality of the simulations, and a good agreement between simulations and observations is achieved in both calibration and validation stages. Different aspects of the flow, i.e., the division of water at two bifurcations in the delta, the effects of the lakes on the flow in the lower part of the system, the area of tidal propagation, are also quantified and discussed.  相似文献   

5.
To obtain comparable results of multi‐element analysis of plant materials by different laboratories, a harmonized sampling procedure for terrestrial and marine ecosystems is essential. The heterogeneous distribution of chemical elements in living organisms is influenced by different biological parameters. These parameters are mainly characterized by genetic predetermination, seasonal changes, edaphic and climatic conditions, and delocalization processes of chemical substances by metabolic activities.

The biological variations of the element content in plants were divided into 5 systematic levels, which are: 1. the plant species; 2. the population; 3. the stand (within an ecosystem); 4. the individual; and 5. the plant compartment. Each of these systematic levels can be related to: 1. genetic variabilities; 2. different climatic, edaphic and anthropogenic influences; 3. microclimatic or microedaphic conditions; 4. age of plants (stage of development), exposure to environmental influences (light, wind, pollution etc.), seasonal changes; and 5. transport and deposition of substances within the different plant compartments (organs, tissues, cells, organelles).

An expert system for random and systematic sampling for multi‐element analysis of environmental materials, such as plants, soils and precipitation is presented. After statistical division of the research area, the program provides advice for contamination‐free collection of environmental samples.  相似文献   

6.
The confusion effect describes the observed decrease in the likelihood that a predator will successfully catch any prey when attacking larger groups of moving prey. We introduce readers to the work of cognitive psychologists interested in human visual attention who have been studying their own version of the confusion effect for many years, developing methods and concepts that may be of fundamental utility to behavioral ecologists. In psychology, ‘basic features’ are characteristics unique to a target object in the visual field that no distracter objects share. Images containing targets with basic features are often less likely to induce the confusion effect in human subjects. Target objects with conjunctions of features, on the other hand, have no individual characteristics unique from distracters, but unique characteristics in combination. Such targets more often induce the confusion effect in humans. We propose the ‘basic feature’ (vs. conjunctions of features) as a new organizing concept for studies on the occurrence of the confusion effect in nature, potentially allowing predictions about which types of prey groups are likely to induce the confusion effect in predators.  相似文献   

7.
An annual quarterly survey of six stations in Yantian Port, Shenzhen, China was conducted from January 2020 to October 2020 to investigate the spatial and temporal distribution of dinoflagellate cysts in the surface sediment of Yantian Port. In total, 36 species representing five groups and two uncertain taxa were identified. The dominant species were Scrippsiella trochoidea, Alexandrium spp., Gymnodinium catenatum, Cochlodinium spp., and Lingulodinium polyedrum. The seasonal difference was not obvious in terms of temporal distribution. The number of species ranged from 32 to 36, and the abundance varied from 297 to 996 cysts/g. The annual average values of the diversity index, richness index, and evenness index were 3.65, 1.55, and 0.93, respectively. The annual number and abundance of heterotrophic species were higher than those of autotrophic species. The number and abundance of species at stations near the dock zone were lower than those near the adjacent area. Notably, six toxic dinoflagellate cysts were found in the surface sediment of Yantian Port, indicating a potential outbreak risk for their vegetative cells in the local coastal area. This study provides a picture of the “Seed Bank” of dinoflagellates near Yantian Port, Shenzhen, and provides a reference value for predicting the occurrence of algal blooms. © 2022 Science Press. All rights reserved.  相似文献   

8.
The phytoplankton of the Bahía Blanca Estuary, Argentina, has been surveyed since 1978. Chlorophyll a, phytoplankton abundance, species composition and physico-chemical variables have been fortnightly recorded. From 1978 to 2002, a single winter–early spring diatom bloom has dominated the main pattern of phytoplankton interannual variability. Such pattern showed noticeable changes since 2006: the absence of the typical winter bloom and changes in phenology, together with the replacement of the dominant blooming species, i.e. Thalassiosira curviseriata, and the appearance of different blooming species, i.e. Cyclotella sp. and Thalassiosira minima. The new pattern showed relatively short-lived diatom blooms that spread throughout the year. In addition, shifts in the phytoplankton size structure toward small-sized diatoms, including the replacement of relatively large Thalassiosira spp. by small Cyclotella species and Chaetoceros species have been noticed. The changes in the phenology and composition of the phytoplankton are mainly attributed to warmer winters and the extremely dry weather conditions evidenced in recent years in the Bahía Blanca area. Changing climate has modified the hydrological features in the inner part of the estuary (i.e. higher temperatures and salinities) and potentially triggered the reorganization of the phytoplankton community. This long-term study provides evidence on species-specific and structural changes at the bottom of the pelagic food web likely related to the recent hydroclimatic conditions in a temperature estuary of the southwestern Atlantic.  相似文献   

9.
Data from National Health and Nutrition Examination Survey for children aged 6–11 years for 1999–2014 were used to study time trends and factors affecting the urinary levels of barium, cobalt, cesium, molybdenum, lead, antimony, thallium, and tungsten. Adjusted levels in urine declined every two years by 5.9% for barium, by 1.2% for cesium, by 18.2% for lead, and by 14% for antimony. For every additional smoker smoking inside a home, the levels of barium increased by 10.6% and for lead by 10%, but for tungsten levels decreased by 7.7%.  相似文献   

10.
Some ecotoxic metals such as Cd, Pb, and Cu in Tessaria absinthioides were quantified to study its possible use as a bio‐indicator and/or bio‐monitor of these metals. This plant was chosen for its abundance in the area under study, along Chile and even in southern Latin America. For Cd, Pb, and Cu in all three parts of the plant (leaves, stems and roots) a different concentration pattern in each sampling areas was observed. In sampling areas Coya Sur and La Cascada copper and cadmium concentration decrease in order: leaves > roots > stems. In samples collected in Xalquincha the lowest concentrations of Cd and Pb were observed in stems. A maximum of cadmium concentration (9ug/gd.w. in leaves) was found in samples from La Cascada, a inflow to river Loa in Calama. High concentrations of lead were found in roots and leaves. Collected data demonstrate that the main pathway for cadmium is from ground water via roots into the plant. Some data obtained for lead and copper indicate that the influence of dust particles adsorbed on leaves and stems can be higher than uptake from ground water.  相似文献   

11.
Although mercury (Hg) mining in the Almadén district ceased in May 2002, the consequences of 2000 years of mining in the district has resulted in the dissemination of Hg into the surrounding environment where it poses an evident risk to biota and human health. This risk needs to be properly evaluated. The uptake of Hg has been found to be plant-specific. To establish the different manners in which plants absorb Hg, we carried out a survey of Hg levels in the soils and plants in the most representative habitats of this Mediterranean area and found that the Hg concentrations varied greatly and were dependent on the sample being tested (0.13–2,695 μg g−1 Hg). For example, the root samples had concentrations ranging from 0.06 (Oenanthe crocata, Rumex induratus) to 1095 (Polypogon monspeliensis) μg g−1 Hg, while in the leaf samples, the range was from 0.16 (Cyperus longus) to 1278 (Polypogon monspeliensis) μg g−1 Hg. There are four well-differentiated patterns of Hg uptake: (1) the rate of uptake is constant, independent of Hg concentration in the soil (e.g., Pistacia lentiscus, Quercus rotundifolia); (2) after an initial linear relationship between uptake and soil concentration, no further increase in Hgplant is observed (e.g., Asparagus acutifolius, Cistus ladanifer); (3) no increase in uptake is recorded until a threshold is surpassed, and thereafter a linear relationship between Hgplant and Hgsoil is established (e.g., Rumex bucephalophorus, Cistus crispus); (4) there is no relationship between Hgplant and Hgsoil (e.g., Oenanthe crocata and Cistus monspeliensis). Overall, the Hg concentrations found in plants from the Almadén district clearly reflect the importance of contamination processes throughout the study region.  相似文献   

12.
The Rarámuri who live in the Sierra Tarahumara of Chihuahua State, Mexico have developed local knowledge and harvesting strategies for edible wild plants that have the effect of conserving the biodiversity of their forest ecosystem. This paper presents the results of ethnobotanical research undertaken in the community of Basìhuare in the Sierra Tarahumara, to provide details on some practical aspects of the Raráamuri worldview regarding interconnections between people and their environment. This traditional philosophy forms the basis for the use of edible wild plants and the harvesting strategies practiced in Basìhuare, such as selective harvesting, environmental modification and domestication. These activities provide the opportunity for harvesters to monitor the landscape and the plant resources that occur on the land, as well as present a setting for the communication and exchange of traditional ecological knowledge. However, Rarámuri harvesting practices are under stress because of increased external pressures from commercial timber extraction and other development. We discuss the state of traditional ecological knowledge and its transmission in the context of development activities in the region. The key to sustainability in the Sierra Tarahumara may be the maintenance of traditional management practices for edible wild plants, and other nontimber forest products, that lead to the conservation of biodiversity by creating patchiness and renewing the plant cover on the land.  相似文献   

13.
Although the peri-urban region around Bogotá, Colombia contains a diversified horticulture sector, local vegetable production suffers from a critical lack of research and availability of un-biased, scientifically validated information on crop management. In this study, we identify current trends and deficiencies in fertilisation and pest management for local vegetable production. We relate pesticide type with target pests, evaluate temporal patterns in pesticide and fertiliser use for a key crop (i.e. spinach) and conduct basic nutrient budget accounting. Personal interviews with vegetable growers were combined with a detailed follow-up of management activities and soil nutrient profiles on pilot farms in two different peri-urban municipalities. Most (84%) vegetable growers relied on personal experience, and indicated a lack of unbiased information on fertiliser effectiveness and pesticide action spectra. The majority of farmers used pesticide mixtures on a calendar basis and commonly applied products below recommended doses. Soil nutrient accounts indicate insufficient fertilisation and a progressive depletion of key nutrients. Extraction rates for the principal vegetable crops exceeded by 33.6%, 20.5% and 93.0% soil nutrient availability of N, P and K, respectively. Organic products are included in local fertilisation schemes, with chicken manure as the principal source, at an average application rate of 6 t ha?1. Our findings could help policymakers and local institutions set a research and extension agenda to promote sustainable peri-urban vegetable production and help secure peri-urban livelihoods while ensuring healthy and safe horticultural production.  相似文献   

14.
The objective of this study is to develop a feedforward neural network (FNN) model to predict the dissolved oxygen in the Gru?a Reservoir, Serbia. The neural network model was developed using experimental data which are collected during a three years. The input variables of the neural network are: water pH, water temperature, chloride, total phosphate, nitrites, nitrates, ammonia, iron, manganese and electrical conductivity. Sensitivity analysis is used to determine the influence of input variables on the dependent variable. The most effective inputs are determined as pH and temperature, while nitrates, chloride and total phosphate are found to be least effective parameters. The Levenberg-Marquardt algorithm is used to train the FNN. The optimal FNN architecture was determined. The FNN architecture having 15 hidden neurons gives the best choice. Results of FNN models have been compared with the measured data on the basis of correlation coefficient (r), mean absolute error (MAE) and mean square error (MSE). Comparing the modelled values by FNN with the experimental data indicates that neural network model provides accurate results.  相似文献   

15.
Wang  Qiugui  Sha  Zhanjiang  Wang  Jinlong  Du  Jinzhou  Hu  Jufang  Ma  Yujun 《Environmental geochemistry and health》2019,41(5):2093-2111
Environmental Geochemistry and Health - Sediment sequences in Lake Qinghai spanning the past 100 years were explored to assess the effects of changes in local land desertification, dust...  相似文献   

16.

This study involved assessing and simulating the probable major pathways (surface and subsurface flow) and hydrogeochemical transport of arsenic (As) in the Beitou–Guandu area, Taiwan. A one-dimensional (1-D) generic, reactive, chemical transport model (PHREEQC) was adopted. The calibrated model showed that As transported to the downstream Guandu plain and Tan Shui river mouth accounted for 50.7 and approximately 100 % of the As in the subsurface flow pathway, respectively, suggesting that subsurface flow constituted a major As pathway. The highest As water concentration occurred near the Beitou geothermal valley because of the low pH and high redox potential in both the surface and subsurface pathways. However, As may be scavenged by aqueous Fe(II) in a reducing environment. The As concentrations in the downstream Guandu plain and Guandu wetland decreased as the simulated time increased, resulting in the adsorption of As on the surface of Fe oxydroxides and limiting the mobility of As in the surface flow pathway. The major retardation mechanism of As mobility in the subsurface flow pathway of the Guandu plain and Guandu wetland was governed by the adsorption reactions of iron-oxide and iron-sulfide minerals. The 1-D transport model was applied to predict the evolution of As in the subsurface flow pathway from 2013 to 2020. The results indicated that the As concentrations in all cells gradually increased. The geochemical redox reactions of As in the subsurface pathway subsequently led to the oxidization of As-bearing sulfides, causing As concentrations to rise substantially in the hillside area.

  相似文献   

17.
Environmental Geochemistry and Health - The importance of environmental geochemistry baseline in soils of O´Higgins Region, Chile, since it hosts in its eastern area one of the major Cu-Mo...  相似文献   

18.
The studies about patterns and impacts of a company’s corporate social responsibility (CSR) programmes on the local communities have been conducted in a number of developed countries. The similar studies, however, were still rarely conducted in developing countries, particularly in Indonesia. This study aims at discussing the impact of the CSR programmes of a cement company on the lifestyles of a rural community in six villages in Tuban district of East Java Province in Indonesia. The study was conducted from January to September 2015, using qualitative data collection and analysis. This study found that the presence of the cement company has made both positive and negative impacts to the rural community. For the positive impacts, we can see the development of infrastructure that makes the villages become more representative; the emergence of new business opportunities, such as food stalls and boarding houses; and the improvement of the quality of human resources through free health care, education, and religious activities. The supports from the cement company, however, have not been distributed equally among the villagers. In addition, we can also see the following negative impacts: the increase of social tense among the villagers due to the tight competition to obtain work in the cement company; the uneasy relation between the local people and the immigrants who work in the cement company; the decrease in the number of people working in agricultural sectors, as most of them have moved or wish to move to the cement company.  相似文献   

19.
Using a standard plot method, the stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) in leaves, litter, and soil (0-20 cm depth) was investigated for three forest types: Populus davidiana, Larix principis-rupprechtii, and Pinus tabuliformis. The results showed that the stoichiometry of C, N, and P of the same component in the three forests were significantly different. The C and N contents in leaves, litter, and soil in P. davidiana forest were higher than those in L. principis-rupprechtii and P. tabuliformis forests were. However, P in the L. principis-rupprechtii forest was higher than that in the P. davidiana forest and P. tabuliformis forests were. The C, N, and P contents of the components in the three forests were, in order, leaves > litter > soil, and the three nutrient contents were significantly higher in leaves and litter than they were in soil. C:N and C:P in the three forests exhibited a trend of litter > leaves > soil, whereas that for N:P was leaves > soil > litter. There were highly significant positive relationships in N:P between the litter and the soil in the P. davidiana forest. Leaf C:N and litter C:P in the L. principis-rupprechtii forest were significantly negatively correlated, whereas N:P in the leaves and soil was positively correlated. There was a significant positive correlation in N:P between the leaves and the soil in the P. tabuliformis forest. In conclusion, the N contents in leaves and soil exhibited a significant positive correlation, whereas there was no significant correlation between C, N, and P in litter or soil. Environmental factors had a large influence on the stoichiometry of C, N, and P in soil. In particular, latitude and altitude had the most significant effects on C, N, P, C:N, and C:P and were significantly p ositively correlated. T hese results provide a scientific basis for f urther studies on nutrient utilization a nd t he cyclic characteristics of different forests in this area. © 2018 Science Press. All rights reserved.  相似文献   

20.
Risk management processes increasingly call for enhanced stakeholder participation, and aim to integrate different risk perceptions, concerns and interests. Frequently, this goal is driven by the increased complexity of risk management processes, as risk management processes continuously have to deal with multi-risk situations including impacts resulting from risks of natural hazards and risks caused by misguided social or economic development. Although stakeholder participation is required by different policies, major challenges still arise from the question of how to perform multi-stakeholder participation in practice. In order to find answers, we tested the so-called ‘bow-tie analysis’ as a potential tool to facilitate multi-stakeholder participation with a major effort on integrating stakeholders risk perceptions and interest in the risk management processes. The bow-tie analysis is a commonly used risk assessment technique (IEC 2009) to analyse cause-and-effect pathways of risks, but its application in multi-stakeholder processes in risk management of natural hazards, especially in a European context, is rather new. Using practical experiences from the trilateral Wadden Sea Region we demonstrate the bow-tie analysis’ contribution to coastal risk management processes in this coastal area by facilitating collaborative identification, comprehension and analysis of the management system. The use of a modified bow-tie analysis in collaboration with stakeholders from the Wadden Sea Region proved to be an appropriate framework for enhancing the understanding of risk management processes and fostered disclosure of different perceptions and concerns of multi-risk problematics. The bow-tie can be beneficial as a communication and co-construction tool in risk management processes in a multi-risk context.  相似文献   

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