54 research outputs found

    Evaluating the potential of a bivalve species from the intertidal zone of the Persian Gulf for biomonitoring of trace elements using a nondestructive analytical method

    Get PDF
    This study was carried out in order to evaluate the potential of the soft and hard tissues of a bivalve species (Callista umbonella) for biomonitoring of different elements in coastal areas of northern part of the Persian Gulf as well as to assess the possible use of PIXE (Proton Induced X-ray Emission) method in this regard. The bivalve specimens and surficial sediment samples were collected from three sampling sites located on the intertidal zone of Hormozgan Province in August 2014. Concentrations of the elements were determined using the non-destructive method, PIXE. Assessment of total organic matter (TOM) and grain size were also carried out in the sediment samples. Based on the results, of the 17 elements measured in the soft tissues, (Al, Br, Ca, Cl, Cr, Fe, K, Mg, Mn, Na, O, P, S, Si, Sr, Ti and Zn) in the case of P, Fe, Br and O significant differences were observed between the sampling sites. Of the 14 elements measured in the shells (Al, Br, Ca, Cl, Cu, Fe, Mg, Mn, Na, K, O, S, Si and Sr) only in the case of Si significant differences between the sites could be detected and of the 14 elements measured in the surface sediments (Al, Ca, Cl, Cr, Fe, Mg, Mn, Na, Ni, K, O, S, Si and Ti) in the case of Na, Mg, S, Cl, K , Ca, Ti and Fe significant differences were found between the sites. In each of the above cases, order of the elements accumulation was assessed and possible causes of the differences evaluated. In order to classify the elements based on their levels in the sediments, soft tissues and shells the multivariate analyses (principal component analysis and cluster analysis) were used. According to the gained results, C. umbonella can be considered as a potential candidate species for biomonitoring of a number of elements in the coastal area of the Persian Gulf

    Shells of Bufonaria echinata as biomonitoring materials of heavy metals (Cd, Ni and Pb) pollution in the Persian Gulf: with emphasis on the annual growth sections

    Get PDF
    Concentrations of heavy metals (Cd, Ni and Pb) were determined in soft and hard tissues (three separated shell sections) of gastropod Bufonaria echinata as well as surficial sediments collected in October 2015 from two sampling sites located in the sub-littoral zone of Qeshm Island, Persian Gulf. There were significant differences between the sampling sites for concentrations of all the three elements in the shells and sediments. But in terms of the soft tissues, in the case of Ni and Pb significant differences between the sites could be observed. In all the cases, higher levels were observed in the samples from Suza site, which may be mainly due to the proximity of this site to the relevant anthropogenic sources. Comparison of the gained data from this study with the other relevant researches shows that in most cases the levels of the elements in the soft tissues and shells either fell within the range for other world areas or were lower. The observed increasing trends of metals accumulation in the shell sections (from older to younger sections) could be mainly attributed to the gradual increase of relevant anthropogenic pollutants in the study area, especially in Suza pier, during the recent years. Generally, it can be concluded that the shells of B.echinata could be possibly employed as a biomonitoring tool for historic metals contamination in northeastern part of the Persian Gulf

    Monitoring on algal bloom event in the southern of Caspian Sea

    Get PDF
    Nutrient enrichment is followed by excessive algal growth (possible in toxic and harmful species); in Caspian Sea in recent decades. So aims of the present study were 1-study on potential of algal bloom at different transects and seasons, 2- determine correlation between potential of algal bloom and environmental parameters using statistical model, and 3- the role of sediment nutrients on algal bloom in the southern Caspian Sea in 2013-2014. The samples of water were collected from four transests (Bandar Anzali, Tonekabon, Bandar Nowshahr and Bandar Amirabad) and three depths (5, 10 and 20 meter) during four seasons. Surface sediments samples were collected at same depths and transects as well. Result showed that organic phosphorous and nitrogen of water were more than inorganic phophorous and nitrogen. Also, maximum and minimum water temperature was obtained at summer and winter, respectively. The values of DO and salinity were more than 5 ml/l and 12 g/l, respectively and pH of water were ranged from weak alkaline to alkaline. Maximum organic and inorganic phosphorous and nitrogen of water were distributed at different transects and seasons. The nitrogen was limiting factor accomponing with phosphorous during spring, summer and fall, but during winter shift to more nitrogen limitation. In addition, the ecosystem was experienced sillicon limitation during winter. Result of sediments showed that inorganic phophorous was maximum during different seasons, however, percent mean of residue-P which contain organic compounds and non-degrediable compounds, was less that 5 percent. Percent of Ca-P was higher than 90, whereas Bioava.-P was less that 10 percent. The order of different forms of phosphorous were registered Ca-P>Org-P>Fe-P>Al-P>Loosely-P. The mian role of adsorbed and desorbed of Loosely-P, Fe-P and Al-P were due to temperature, Eh and pH, respectively. Annual percent of TON was two folds than TIN and NH4/N was also three times than NO_3/N. Minimun and maximum of phytoplankton abundance were obserbed in summer (73±31 million cells/m3) and winter (505±55 million cells/m3), respectively. Statiscal analysis (ANOVA) showed that phytoplankton abundance significantly increased in winter compared to the other seasons (P1000 cells/ml) during spring. Maximum abundance of phytoplankton was mainly registered at Anzali and Amirabad transects.The re-existence of Thalassionema nitzschioides (as valuble food in food chain) in dominant species list (same as the stability year of ecosystem) and decreasing of percent abundance of harmful species to the dewell and native species are good sign of good quality of the Caspian Sea water. However, Pseudonitzschia seriata expansion of the cold season to other seasons (even in summer) is important point. Pseudonitzschia seriata as harmful algae and its ability to produce toxin and potential bloom, high percent frequency and abundance during the study has important role in environmental issues of the Caspian Sea.It seems that temperature changes in different parts of the Caspian Sea in each season (except fall season) was obtained in the range of dominant species needed, therefore, it had less importance compared to nutrients. Trophic status was meso-eutroph during fall and winter seasons which was higher level than spring and summer (mesotroph). The Stephanodiscus abundance increased at Anzali transet due to nutrients enrichment of water in spring. Excessive use of silica in the spring, summer caused dominant of non Diatoms species (Binuclearia lauterbornii) and low content of Diatoms species (Chaetoceros throndsenii). In fall, high abundance of Bacillariophyta (Thalassionema nitzschioides) accompanied with consuming of silicon and ammonium. The statistical analysis also showed significant correlation between Bacillariophyta and Thalassionema nitzschioides abundance and Si/N ratio. Subsequently, the excessive use of silica in autumn and winter (due to high abundance Bacillariophyta and dominant species including Pseudonitzschia seriata and Dactyliosolen fragilissima) cause severely declined dissolved silica, and for the first time in winter, silicon was limited factor for phytoplankton growth. In addition, the results showed that there were positive correlations between abundance of dominant species and nutrients of sediments in all seasons. This is shows that some species of phytoplankton, even though the limitation of nitrogen and phosphorus in the water, are able to supply the nutrients required from the surface sediments. It would be more importance in the present study, which higher concentration of different forms of phosphorus and nitrogen in sediments as compared to the deep water, provide transport of nitrogen and phosphorus from sediment to water column

    Quantitative assessment of the impact of Mnemiopsis leidyi on the southern Caspian zooplankton structure during 1996-2010

    Get PDF
    After the arrival of the invasive species (Mnemiopsis leidyi) in the Caspian Sea (in 1999) significant changes have been occurred in the ecosystem. In the present study, the data concerning the period 1996 to 2010 (extracted from the relevant research projects) were analyzed. The period was classified into two phases, before and after the species invasion (1996 and 2001-2010). In our study, the impact of the invasive species on the structure of southern Caspian zooplankton communities was assessed during the period 2001-2010, quantitatively. The combination of abundance and distribution range of the species (ADR) during the period 2001-2009 and the year 2010 were evaluated as E (occurrence in high numbers in all localities) and D (occurrence in moderate numbers in all localities), respectively. Considering the obtained results, the year 2001, in which the relative biomass was more than 90 percent, could be considered as the expansion phase and the following years (2002-2010) as the adjustment phase. With regards to the loss of the keystone and some other native species after the invasion of M. leidyi (2001 to 2010), the impact of the invasive species on the structure of southern Caspian zooplankton communities was assessed as massive (C4)

    Investigation on the potential use of aquatic plants for biomonitoring of the important aquatic ecosystems of the country-the first phase: Anzali wetland

    Get PDF
    This research project was conducted during 2007-2008 in Anzali wetland, aiming feasibility study on aquatic plants different species (emerged, sub emerged and floating leaved plants) as essential and non essential elements concentration Biological indicators utilization including Ni, B, Cd, Pb, Cu, Mo, Se, Si, Cl, Zn, Mn, Fe, Na, Mg and Ca. and their tolerance and capabilities assessment toward exposing different elements and study on water and sediments rational role in elements absorption and important environmental factors (DO, pH, etc…) effects on absorbed quantities. Azolla filiculoides, Hydrocotyle vulgaris, Ceratophyllum demersum,Trapa natans were the gathered aquatic plants field samples. Water and sediment samples were also collected from Shijan, Abkenar and Siahkeshim sampling sites respecting 1, 2 and 3 and were digested according to the standard methods. Element concentrations were determined using ICP-AES and AAS. Lab samples were Hydrocotyle , Lemna , Ceratophyllum and exposed to Ni, Zn, Cd, Pb, Cu and Ca in Swedish standard, (SIS), Lemna growth Medium 648, Hogland's E+Medium (22,23) implementation. The results shows a significant variation (p≤ 0/0001) among the plants, sampling sites and the elements which is compatible with previous similar projects results at national and international scales, rationally. Totally pattern of the elements occurrence in the plants would be: Cd 1>3 and this is 1>2>3 for hazy and no trend for TOM variations. The lab samples test results on metal concentration illustrates Hydrocotyle and Ceratophyllum similar trends for maximum Zn and minimum Pb absorbing. However, for Lemna the highest and least absorption rates belong to Ni and Cd. Density factor sequence in heavy metals exposed lab samples would be: Lemna > Hydrocotyle > Ceratophyllum

    Ecological study on the Persian Gulf Martyres Lake, Tehran

    Get PDF
    The ecological study of the Persian Gulf Martyres Lake carried out at the 5 stations between 2013 and 2014. This study identified 35 phytoplankton taxa. The diatoms taxa was dominated and their abundance recorded highest (2000 000 cell. L^-1) in the lake. The annual phytoplankton abundance was measured as 2500 000 cell. L^-1 during the study. The total nitrogen and water temperature were the significant a biotic parameters to increase cyanophytes abundance. Furthermore, 37 zooplankton taxa were identified. The Rotatoria abundance was dominated zooplankton. The annual zooplankton abundance was measured as 72 ind.l-1. Based on the CCA, there was no correlation between Rotatoria abundance and a biotic parameters. The study benthos showed Ephemeroptera and Diptera abundance were dominated; artificial bottom and lack of sediment and organic matters were the main reasons in decreasing of the benthos density. The Chitgar lake is the poorest lake in Iran due to low density of plankton and benthos organisms. The estimation of fish production was 123 kg/ha and for the lake was determaind 16 tonne. The finding display, invasive species was the main fish Chitgar lake that would be negative effect and increase eutriphication trend in the lake. Phosphorus parameter was limited parameters and trophy level recorded low due to high N/P ration in the lake. In overall the Chitgar lake situation is in Oligotrophic category with the low trophy level

    Laboratories risks evaluation in national fish processing research center laboratories

    Get PDF
    Risks assessment of laboratories of National Fish Processing Research Center was done in 2014 and 2015 to determine the risk factors, potential risks and provide action plans to prevent the occurrence of any risks and increasing awareness of staff to safety issues. All laboratories: Chemistry, Microbiology, sensitive assessment and physical were visited and all factors were evaluated. The method for evaluation was with Failure Mode and Effects Analysis (FMEA) methods. The assessment process was designed and implemented in two phases, the first phase was the current situation of safety indexes, risks identification and distance to laboratory safety parameters included: working environment, physical factors, test methods and the human factors were done, then risk assessment and risk management of identified risks were followed by check list forms. The second phase was based on the findings, control measures and safety guidelines were done and provided. the highest risk score related to Microbiology laboratory with RPN 540 and then chemistry 360, because of the nature of sensory laboratory was not evaluated and There was no experiments in the physics laboratory and was ignored. After control measures, the risk number of laboratories decreased as follows: Microbiology to 18, chemistry to 12

    Laboratories risks evaluation of Persian Gulf and Oman Sea Ecological Research Center

    Get PDF
    In this study, to assess and classify risks associated with working in the laboratories of Persian Gulf and Oman Sea Ecological Research Center, the method of "Failure Mode Effects Analysis" (FMEA) as well as some statistical methods were used. The results of the risk assessment in the 11 affiliated laboratories showed that the risk levels in all cases, except for benthos laboratory, could be evaluated as moderate or high and therefore appropriate corrective actions must be implemented. Based on the results of the Kruskal-Wallis tests both before and after the corrective actions, there were significant differences between the laboratories from the viewpoint of risk priority number (RPN). The post hoc tests showed the lowest risk levels for the benthose and histology laboratories, while the highest risks identified in the laboratory of instrumental analysis. The results of the classification of the laboratories using cluster analysis are largely similar to those of the posthoc tests. According to Mann-Whitney U test, only in the case of the samples preparation laboratory, significant differences between the values of the RPN before and after the corrective actions could be observed (p> 0.05), however, the risk levels still remained high. In general it can be concluded that FMEA is an effective method for risk assessment in the research laboratories and appropriate statistical methods can also be used for complementary analysis

    Quantitative assessment of biopllution caused by Mnemiopsis leidyi on ecological community structure in the southern part of the Caspian Sea

    Get PDF
    After the arrival of the invasive spexies (Mnemiopsis leidyi) in the ecosystem of Caspian Sea in 1999, It had notable impacts. In this study, we,re assessing impacts of quantitative M. leidyi as a biopllutant on zooplankton community in the southern part of the Caspian Sea during 2001-2010 period. It becomes clear that Abundance and Distribution Range (ADR) of M.leidyi during 2001-2009 was in class E(occurrence in high numbers in all localities) and in year 2010 was in class D(occurrence in moderate numbers in all localities). from 2001- 2009, ADR in Summer season was in class E, but in summer 2010, relatinve biomass of M.leidyi has decreased and ADR was evaluated as D. During the fall seasons of 2001 -2010, only in fall of 2003 and 2010, the ADR was C(occurrence in low numbers in all localities) and D respectively and in other years, the ADR was in class E. In winter season relative biomass of M.leidyi decreased and only in winter of 2001 relative biomass was high and the highest ADR (class E). In winter 2003 and 2004, ADR was in class D. The biomass of M.leidyi was found to be zero in winter 2008. From winter of 2009-2010,ADR, were assessed B and A respectively. In the spring, ADR was evaluated A and D. Considering the obtained results, the yesr 2001, which the relative niomass was more than 90 percent, could be considered as the expantion phase and the following years (2002-2010) with regard to decrease of relative biomass as the adjustment phase. With regards to the loss of the keystone species (Eurytemora sP.) and some other native species, our evalution showed that the impact of M.leidyi on structure of zooplankton community was assessed as massive (C4).During summer and fall seasons that biomass of M.leidyi was higher than 50%, only A.tonsa exist, but during spring and winter seasons that biomass of M.leidyi was decreased and more species have a chance to exist
    • …
    corecore