RESUMEN
There is always an adamant need to comprehend and draw the complex challenges of sustainability in order to help organize studies, due to the increasing human-related pressures on coastal zones. Hence, by formulating such a comprehensive framework, it could be possible to anticipate changes and support managerial decisions, as well as the degree of resilience of the region's environment. One of the approaches utilized in littoral or coastal zones is the conceptual framework of drivers, pressure, status, impact, and responses (DPSIR)..Qeshm Island, the largest island in the Persian Gulf, is accounted for being the most vital and strategic areas of the mentioned region. In recent decades, Qeshm has become one of the major cultural, natural, geological, and tourism hubs of the country due to its unique regional characteristics, along with its biodiversity and environmental sensitivity. Thereby, in the present research, a combined approach shall be followed to explore the resilience of the marine environment on the northern coast of Qeshm Island by taking advantage of the socioeconomic criterion. In this respect, the conceptual framework of the DPSIR model is utilized in combination with the structural equation model (SEM-PLS) (or partial least squares), which is one of the nonexperimental techniques, to quantify the results in the best manner possible. On the basis of the fuzzy cognitive map (FCM), the regional economic index bearing the weights of 0.62, 0.62, and 0.5, along with an institutional-managerial and biological index, respectively, denotes a two-way positive correlation, whereas this factor has a two-way, but adverse correlation, relationship with a weight of 0.65 in terms of the sociocultural index. Similarly, there is also a one-way and negative relationship, as to the economic index, with a weight of 0.69 which is in relevance with the physio-chemical index.
Asunto(s)
Ecosistema , Monitoreo del Ambiente , Biodiversidad , Humanos , Océano ÍndicoRESUMEN
The distribution and origins of Ni and V were assigned in the surficial sediments from 160 stations in Shadegan international wetlands with 537,700 ha. The findings showed that the mean total content of Ni and V in the surface sediments were 45.08 ± 12.09 and 25.25 ± 20.8 µg g-1 dw, respectively. According to the analysis chemical speciation, the Ni and V residual fraction in the surface sediments were calculated for > 80% of the total level of metals, indicating that the metals may be an indicator for the input of natural resources. The analysis of the interpolation maps according to their chemical fractionation manifested that the Ni and V pollution hotspots have been happened in the northern, southern, and western points. Interpolation maps also highlighted that Ni and V are often controlled by natural factors like parent material; however, anthropogenic inputs have also caused the accumulation of these metals in the sediment.
Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Animales , Animales Salvajes , Monitoreo del Ambiente , Sedimentos Geológicos , Océano Índico , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
This research focuses on the fractionation and distribution patterns of heavy metals (Zn, Cu, and Fe) in surficial sediments collected from Shadegan Wildlife Refuge, the biggest wetland in southern part of Iran, to provide an overall classification for the sources of metals in the study area using a sequential extraction method. For this purpose, a four-step sequential extraction technique was applied to define the partitioning of the metals into different geochemical phases of the sediment. The results illustrated that the average total level of Zn, Cu, and Fe in surface sediments were 55.20 ± 16.04, 22.86 ± 5.68, and 25,979.01 ± 6917.91 µg/g dw, respectively. On the average, the chemical partitioning of all metals in most stations was in the order of residual >oxidizable-organic > acid-reducible > exchangeable. In the same way, the results of calculated geochemical indices revealed that Cu, Zn, and Fe concentrations are mainly influenced by lithogenic origins. Compared with consensus-based SQGs, Cu was likely to result in occasionally harmful biological effects on the biota.
Asunto(s)
Monitoreo del Ambiente/métodos , Sedimentos Geológicos/química , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisis , Humedales , Fraccionamiento Químico , Cobre/análisis , Irán , Hierro/análisis , Zinc/análisisRESUMEN
In this study, total concentration and speciation of heavy metals in sediments of the Asaluyeh, one of the Iran's largest commercial ports, are investigated. 48 sediment samples were collected and analyzed for trace and major elements. Sediment quality guidelines along with calculated enrichment factors and trace metal profiles indicate that Asaluyeh port is threated by contamination, especially with respect to Hg and Cu. Normalization to Sc indicated high enrichment factors in the sediments following the decreasing order of: Hg>Cu>As>Ni>Zn>Pb≈Cr≈Mn>Co≈V≈Fe≈Al. Hg displayed the greatest potential ecological risk factor among sampling stations. The results of sequential extraction procedure revealed that in some stations >50% of Mn, V, Cu and Zn occur in potentially mobile phases and therefore are more readily mobilized in the sediments of the study area.
Asunto(s)
Monitoreo del Ambiente , Sedimentos Geológicos , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisis , Océano ÍndicoRESUMEN
Unplanned growth of cities is a matter of concern these days. Lack of attention to proper patterns of urban development has left so many harmful effects on human health and the environment. One of the most effective methods that can be used to measure the efficiency of urban development is data envelopment analysis (DEA). The present study is an attempt to evaluate the performance and efficiency of development of Yazd City using the DEA over the years 1983-2013. In this regard, the ecological factors, affecting the growth of the city of Yazd in the study period, were identified initially. The factors include elevation, slope, aspect, geology, morphology, soil, water quantity, climatic features, and land cover. Next, using variable returns to scale (BCC) based on the output-oriented approach, the efficiency of development of Yazd City was calculated by GAMS software to recognize efficient and inefficient units. Then, Anderson-Peterson (AP) ranking method was used to rank the most efficient units in the development of Yazd City over the study years. The obtained results indicated that the DMUs 2 (1984), 3 (1986), 12 (1994), 15 (1997), 21 (2004), up to 30 (2013) were efficient and introduced as units with proper performance in terms of ecological indicators affecting the urban growth. According to the Anderson-Peterson method, DMU 3 (1986) was recognized as the most efficient unit, ranked the highest (with a score of 1.20319) among the other 30 units in terms of ecological indicators affecting development of the urban growth. The research findings could clarify the strength and weak points of the ecological characteristics of the city. According to which, a comprehensive understanding of the performance of the city could be given to relevant authorities in order to amend inefficient units of urban development or direct the orientation of the city growth toward the most efficient directions.
Asunto(s)
Monitoreo del Ambiente/métodos , Remodelación Urbana , Ciudades , IránRESUMEN
The total concentrations and chemical partitioning of Ni, V and Fe have been assessed in surface sediments from 160 sites along the Shadegan wildlife refuge. The results showed that the average total level of Ni, V and Fe in surface sediments were 45.08±12.09, 25.25±20.8 and 25,979.01±6917.91µg/g dw, respectively. On the average, the chemical speciation of Ni, V and Fe in most stations were in the order of residual>oxidisable-organic>acid-reducible>exchangeable. In all fractions, the residual was accounted the highest proportion for the metals analyzed. Among the non-residual phases, the proportion of heavy metals in organic matter fraction was higher than other phases collected from all locations. The comparison between measured values in this study and some fresh water sediment quality guidelines indicated that the levels of nickel would be expected to sporadically cause harmful biological impacts on biota in the Shadegan wildlife refuge.
Asunto(s)
Sedimentos Geológicos/análisis , Níquel/análisis , Contaminación por Petróleo/análisis , Vanadio/análisis , Contaminantes Químicos del Agua/análisis , Monitoreo del Ambiente/métodos , Irán , Hierro/análisis , Metales Pesados/análisis , HumedalesRESUMEN
A total of 48 water samples and 24 sediment samples were collected at four sampling stations along the wetland during four seasons from 2009 to 2010 and analyzed by gas chromatograph-electron capture detector (GC-ECD). In water the total concentration of OCPs was 0.33, 0.01, 0.1 and 0.07 mg/L in summer, autumn, winter and spring, respectively. The most frequent OCP compounds detected were endrin and chlordane (0.08 and 0.07 mg/L), heaxachlorobenzene and chlordane (0.06, 0.02 mg/L), and chlordane (0.07 mg/L) in summer, winter and spring, respectively. The maximum concentration of ΣOCPs was found in samples collected from station 1 in summer (0.26 mg/L). In sediments the total concentrations of OCPs were 15.84 and 2.62 mg/g-dry weight (dw) in summer and winter, respectively. Chlordane was the most frequently found OCP compound, followed by lindane, 9.92 and 2.47 mg/g-dry weight (dw), respectively, in summer. While, lindane (2.52 mg/g-dw) and endosulfan I (0.1 mg/g-dw) were the highest OCP compounds detected in winter. The results obtained in this study show that there still exist a variety of organochlorine pesticide residues in the water and sediments from the Amir-kalaye wetland in Iran.
Asunto(s)
Monitoreo del Ambiente , Hidrocarburos Clorados/análisis , Plaguicidas/análisis , Humedales , Agua Dulce/química , Sedimentos Geológicos/química , Irán , Modelos Químicos , Contaminación Química del Agua/estadística & datos numéricosRESUMEN
This study aims to investigate the pollution rate of heavy metals on the western seaboard of Bandarabbas in southeast Iran using a new pollution index. The bulk of the analysis was conducted on sediments, followed by selection of a few samples to perform experiments on chemical partitioning studies as well as biological accessibility. On this basis, the proportions of natural and anthropogenic elements were calculated. Finally, with regard to chemical separation results, the pollution rate was calculated based on Muller's geo-chemical index, enrichment factor, pollution index, and a new "Risk" index. Chemical separation showed the anthropogenic origin of elements are as follows: Ni(27.5%) > Zn(6.5%) > Pb(2%) > Al (0.2%). The newly developed pollution index is indicative of "low environmental pollution "for Ni.
Asunto(s)
Sedimentos Geológicos/química , Metales Pesados/análisis , Contaminantes del Agua/análisis , IránRESUMEN
The concentration and bioavailability of Ni, Cu, Cd, Zn, and Pb in the sediments and leaves of grey mangrove, Avicennia marina, were studied throughout Sirik Azini creek (Iran) with a view to determine heavy metals bioavailability, and two methods were used. Results show that Zn and Ni had the highest concentrations in the sediments, while Cd and Cu were found to have the lowest concentrations in the sediments. Compared to the mean concentrations of heavy metals in sedimentary rock (shales), Zn and Cu showed lower concentration, possibly indicating that the origin of these heavy metals is natural. A geo-accumulation index (Igeo) was used to determine the degree of contamination in the sediments. Igeo values for Zn, Cu, Pb, and Ni showed that there is no pollution from these metals in the study area. As heavy metal concentrations in leaves were higher than the bioavailable fraction of metals in sediments, it follows that bioconcentration factors (leaf/bioavailable sediment) for some metals were higher than 1.