seid omid aleyasin; bahman shamsesfandabad; Hamid Toranjzar; abas ahmadi; Shahro Mokhtari
Abstract
Abstract: Wetlands are one of the most productive ecosystems in the world. They provide a unique and rich habitat for creature .they also perform a wide range of economic and service functions such as water conservation, runoff regulation, water quality treatment and recreational services. The aim of ...
Read More
Abstract: Wetlands are one of the most productive ecosystems in the world. They provide a unique and rich habitat for creature .they also perform a wide range of economic and service functions such as water conservation, runoff regulation, water quality treatment and recreational services. The aim of this study was to evaluate the ecosystem health of Meyghan Wetland of Arak based on different methods. To evaluate the Meyghan Wetland of Arak and also to evaluate the status of benthic organisms and other parameters, sampling of sediments of the wetland floor was performed. Sampling was performed at 10 points of the wetland and at 5 replications at each point. Several indicators were used to assess the health of Meyghan Wetland. Which included a biotic-index (BI) based on the work of Borja et al. (2000). In addition to the above, the main framework includes bio-indicators, heavy metal pollution index and water quality index, which have been considered in this study. The ecosystem health of Meyghan Wetland was evaluated based on the mentioned indicators and the map of ecosystem health of Meyghan Wetland was prepared. The results of this study showed that except for the nickel, zinc and lead as well as pH, for other elements (EC, Na, Cl, Mg, Ca, HCO3, SO4 and TDS), the lowest and highest values belong respectively To stations 3 and 6. The high amount of these elements in station 6 can be due to the activity of sodium sulfate factory in the northern part of the wetland, which causes changes in the wetland ecosystem by removing sediments from the wetland floor. In the case of copper, zinc and lead, the lowest concentration is seen in the northwestern part of the wetland and the highest concentration is seen in the western and southeastern parts of the wetland.
Kianfar payamani; Eisa Solgi; Kazem Rangzan; Taher Farhadinejad
Abstract
Sediments can be sensitive indicators for monitoring contaminants in aquatic environments. Therefore, understanding the mechanisms of accumulation and geochemical distribution of heavy metals in aquatic systems and providing basic information for judging environmental health risks, spatial study of metal ...
Read More
Sediments can be sensitive indicators for monitoring contaminants in aquatic environments. Therefore, understanding the mechanisms of accumulation and geochemical distribution of heavy metals in aquatic systems and providing basic information for judging environmental health risks, spatial study of metal concentrations in sediments and their comparison with non-contaminated bases is of great importance. One of the common methods of soil pollution assessment is the use of pollution factor index (CF). The calculation of this index requires determining the background of the elements under study. For this purpose, statistical methods based on mean and standard deviation of data are commonly used. Due to the skuwness of the distribution of geochemical data, the use of this parametric method is limited, so the use of methods resistant to outlier data can be proposed as an alternative approach. In the last two decades, the fractal method has been used to separate communities in data related to many disciplines of earth sciences. In order to evaluate the two mentioned methods, 770 samples of waterway sediments containing six metal elements of As, Cr, Cu, Ni, Pb and Zn were collected in an area that is located in the north of Khorramabad. The background of the elements was determined by both methods (statistical method resistant to outlier data and fractal method) and finally the CF index was calculated. This index based on statistical methods assessed at the intermediate level for arsenic, chromium, copper, nickel, lead and zinc 7.5, 0.8, 5.5, 0.5, 4.7 and 9.2 percent, respectively. For the mentioned elements based on fractal method, the medium level of contamination were 39%, 28.9%, 88.6%, 39.4%, 45.7%, 73.4% of the total sample, respectively. In addition, with the second method, 3% (copper), 0.1% (lead) and 4.3% (zinc) of the number of samples have been evaluated at a considerable level. The results showed that the use of statistical methods in determining the background of the elements, despite the selection of a statistical method appropriate to the distribution of data, has reduced the sensitivity of the pollution index and reduced the efficiency of the index in the separation of pollution classes. While the use of fractal method due to considering the spatial dimension (area) in separating different background communities from anomalies leads to better efficiency of CF index and thus improves regional pollution estimates.
hasan izanloo; kaka shahedi; karim solaimani
Abstract
Assessment of metals absorbed to suspended solids in urban floods, allows managers to take measures to improve the quality of the urban environment. This article examines the changes in the concentration of heavy metals such as lead, zinc and copper in suspended load of runoff from the Bojnourd urban ...
Read More
Assessment of metals absorbed to suspended solids in urban floods, allows managers to take measures to improve the quality of the urban environment. This article examines the changes in the concentration of heavy metals such as lead, zinc and copper in suspended load of runoff from the Bojnourd urban watershed in autumn and spring seasons. For this reason, 52 samples were collected. After preparing the samples, separation of suspended sediment using the Whatman filter paper and then weighing the amount of sediment in runoff, using atomic absorption, the amount of heavy metals dissolved in runoff and heavy metals absorbed to suspended solids in runoff were measured in terms of ppb. The results showed that the amount of suspended sediment weight is higher in spring than autumn. Results indicated that the maximum concentration of insoluble heavy metals and attached to sediments is more than soluble heavy metals in runoff. On the other hand, the results revealed that the mean maximum concentration of zinc and copper, except lead attached to sediments, is higher in the spring than autumn and the spatial concentration of zinc and copper in samples of runoff suspended sediments from Sandalabad Stream (FC3S) is higher. While on the lead, concentration for the samples taken from the runoff pathways and drainage network (FB2S) was higher. However, the difference in location of data for heavy metals absorbed to suspended sediments is not statistically significant. The Pearson correlation test results showed that there is a positive but low correlation between lead and zinc (r =0.166) in the autumn and the lead and copper (r=0.271) in the spring. Significance of this correlation is certified using hierarchical cluster analysis method.
