جستجوی مقالات مرتبط با کلیدواژه « شاخص زیستی » در نشریات گروه « زیست شناسی »

In the present study, the possibility of using macrobenthos as a biological indicator to assess the level of contamination of the rust estuary with heavy metals has been investigated.

Sampling was performed in 2016 from 4 stations in Zangi estuary at full tide.Sediment was harvested from each station using Van Wen (with a cross section of 0.025 m2) to identify benthos, determine heavy metals in sediment, determine organic matter and granulate sediments. In all 4 stations, clay particles formed the main part of the sediments.

The range of organic matter was 6.90-6.98%, with station 3 having the highest percentage and station 4 having the lowest percentage of organic matter. The identified macrobenthos in Zangi estuary were divided into five categories: Bivalvia, Gastopoda, Polychaeta, Crustacea and Fish and 26 genera and species. Station 1 with 13 species had the highest number of species and Station 2 had the highest number of macrobenthos per square meter and the highest Shannon diversity and uniformity index. Species of Hydroides sp. Polychaeta with 25.97% had the highest frequency in the population of Zangi estuary macrobenthos. Accordingly, Polychaeta with 49.1% and Bivalvia with 37.21% had the most abundant category and fish with 0.86% had the lowest frequency. Polychaeta class in stations 1 and 4 with 63.26 and 56.1% and Bivalvia class in stations 2 and 3 with 44 and 33.06%, respectively, had the highest percentage. Zinc, nickel and chromium had the highest concentrations with averages of 32.41, 23.13 and 19.16 mg/kg.Selenium had the lowest concentration in all 4 stations. The mean concentrations of heavy metals in stations 2 and 3 were significantly less polluted with stations 1 and 4 (p <0.05). Calculation of the degree of pollution in 4 stations of Zangi estuary showed the degree of severely polluted for these stations. Based on the contamination factor, except for vanadium at all stations and lead metal at station 2, which is in the highly contaminated range, other metals were in the low to high contamination range. Thus, the concentration of all metals in the bell ring was in the alarming state.

The results of the present study showed that the first and most important factor influencing the distribution of estuarine macrobenthos was the percentage of bed clay particles, heavy metals such as cadmium, lead, nickel, vanadium, chromium and zinc and then the organic matter in the bed. Also, copper metal had the least effect and correlation with the number of macrobenthos among the studied metals.

Macrobenthos communities are used as the second and third levels of food chain, and can be considered as an index of total production and water quality. This study aimed to investigate the density and abundance of macrobenthos in the Zayandeh-rood River in 2017 and use them to determine the river water quality. For this purpose, 6 sampling stations were selected completely randomly and sediment samples was collected at each station with three replications in 4 seasons. Benthos identification was performed using binocular stereomicroscope and Benthos identifiers keys. Finally, 9 families and 7 order were identified, among which Monhysteridae, Oligochaeta and Hirudinea had the highest abundance. All seasons and stations are classified as serious organic pollutants based on the ASPT index. According to the EPT index, in spring, water quality was assessed as good. Summer and fall were in poor and winter in very poor quality class. Shannon Weiner index for all seasons is in the moderately pollution class. All of the seasons according to the BMWP index, were in moderately class. Based on BMWP index, stations 1 and 3, the water in poor quality and the other stations were in the moderately quality.

The purpose of this study is to conduct a qualitative analysis of Zayandeh-rood River water using benthic invertebrate communities in fall 2017 to Spring 2018. To do so, we select 6 stations and 3 sediment samples were collected in each stations. Sediment samples were fixated and various animals were extracted from the samples and were grouped and identified according to fauna benthic identification keys were used for the identification of the sample. Finally, in spring 8 family belongs to 6 order; in autumn 11 family belongs to 7 order and in winter 6 family belongs to 4 order were identified. According to all indices, all stations and all seasons were in polluted category. Regarding the Zayandeh-rood drought, during the last decade, the flow of water in the river, especially the refinery stations and the Shakh-kenar and Sharif Abad, is practically the industrial wastewater, sewage of the cities and adjacent villages. For this reason, contaminated species in these ecosystems are species resistant to pollution.

The amount of the blood plasma/serum components can be a useful tool for monitoring health status, detecting illnesses and responses to therapy. This study was conducted to determine the concentrations of blood plasma/serum components of Periophthalmus argentilineatus at different regions of Bandar abbas coastal. The specimens were collected from three stations including (St1), (St2) and (St3) estuaries of Bandar Abbas coastal waters in summer 2015. A total of 90 specimens were measured to the nearest 0.1 cm of total length (TL) and 0.01 g body weight (BW). In research conducted on following blood plasma/serum components including Alanine S Transferase, Alkaline phosphatase, glucose, cholesterol, triglyceride, T4, T3 and TSH were measured in P. argentilineatus. The results showed that the plasma enzyme levels were higher in fish from the polluted location. Concentrations of thyroid hormones, glucose and cholesterol were significantly higher in fish from St3 than those from other stations (P<0.01). According to the results of this study, it is necessary to monitor the contaminants bioaccumulation in Bandar Abbas coastal waters. This will give an indication of the temporal and spatial extent of the process, and an assessment of the potential impact on aquatic organism’s health.

This study aimed to assess the ecological status of Khamir, Tiyab and Jagin creeks and the impact of human activities on the studied ecosystems using AMBI biological indicator. During the study period, 165 macro-benthos taxa belong to seven phyla including Annelids (65 taxa), Mollusca (65 taxa), Arthropods (28 taxa), Echinoderms (3 taxa), Hydrozoans (2 taxa), Nemertea (1 taxon) and Nematoda (1 taxon) were identified. For the total abundance, Polychaeta showed the richest taxonomic feature with 62 species, contributed 37.57% of the total abundance. The average values of AMBI in the four seasons ranged from 1.12±0.09 (spring) to 5.08±0.15 (autumn). The highest values occurred at station 6 (spring, 4.12±0.81; summer, 5.01±0.56; autumn, 5.08±0.15; winter, 4.42±0.38), and the lowest values occurred at stations 7 (spring, 1.12±0.09; summer, 1.24±0.07), and 1 (autumn, 1.25±0.07; winter, 1.33±0.24). Results from ecological status of studied creeks using AMBI index throughout the year showed that Khamir creek classified as "slightly polluted" to "moderately polluted", Tiyab creek classified as "slightly polluted" to "heavily polluted" and Jagin creek classified as "slightly polluted". The findings of this study revealed that the AMBI index is suitable for separation of areas with less impacted by human activities from areas affected by these activities and could be used as a robust management tool for monitoring programs.

The rivers are under threat by numerous pollutions and their quality assessment is a need. Water quality of the Gamasiab River in Kermanshah Province was assessed using biological indices (BMWP and ASPT method). Six stations were selected and macro invertebrates were collected by surber sampler from July 2013 to May 2014. In this study, 11 families of the macro invertebrates from 10 orders were identified; Gammaridae، Lymnaeidae and Chironomidae were the most dominant, respectively. After identifying and counting the macro invertebrates, ASPT and BMWP indices were calculated to determine the contamination of Gamasiab River. BMWP mean showed significant differences between all stations and stages (P < 0.05). Except for station 6 that was in very good class, the water quality of the Gamasiab River was classified as middle to bad condition. ASPT mean showed significant differences between stations (P < 0.01) and classified the water quality of Gamasiab River in the category 4. According to the results, environmental and ecological characteristics of Gamasiab River are moderate.

Nowadays, the entrance of pollutants including heavy metals in environment threatens the life of aquatic animals. In this study, the effect of zinc chloride (6 mg/l) and cadmium chloride (5 mg/l) exposure were studied on the activity of some metabolic enzymes in the liver, gills, brain and muscle in Snow trout (Schizothorax zarudnyi). The results showed that zinc caused a significant increase in AChE activity in the brain, AST activity in the liver and muscle and ALP activities only in the liver (p˂0.05). Exposure to cadmium significantly decreased acetylcholinesterase in the brain (p˂0.05). However, ALT activity in the liver and gills and AST activity only in the gills was increased significantly following cadmium exposure. Cadmium stimulatory effects on ALP in tissues were not statistically significant. Based on the above result, in this Species exposed to cadmium showed more toxicity than zinc, and the most sensitivity and susceptibility to the presence of cadmium and zinc in the environment was seen in livers of fish. Assessing levels of metabolic enzymes in the liver tissue and AChE enzyme in the brain tissue of Snow trout has the potential to be used as a suitable indicator to show heavy metal pollution in the aquatic ecosystem.