فهرست مطالب

Caspian Journal of Environmental Sciences - Volume:17 Issue: 4, Autumn 2019

Caspian Journal of Environmental Sciences
Volume:17 Issue: 4, Autumn 2019

  • تاریخ انتشار: 1398/09/10
  • تعداد عناوین: 8
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  • S. Reddy Sajjala*, S.K. Al Dawery, A. Ahmed, M.Al.N. Al Jabri Pages 285-294

    In this study an attempt has been made to disinfect total coliform bacteria present in Falaj water using solar water disinfection (SODIS) technology. SODIS experiments were conducted in winter (February 2018) and summer (May 2018) using polyethylene terephthalate (PET) bottles (less, thin and thick plastic PETs) and the glass ones of different capacities (0.5, 1 and 1.5 L). The results showed that total coliform disinfection rate in May was two folds greater than that in February. Water depth or volume of sample in the bottle had significant effect on the efficiency of SODIS. Highest disinfection rate was found on the samples collected from water depth of 6 cm (0.5 L), while the lowest was observed on samples of 8 cm in depth (1.5 L). No significant difference was observed in disinfecting total coliform between glass and less plastic PET bottle for shorter exposure periods (1 h).  Results of this research have proved SODIS as anappropriate household water treatment and safe storage for disinfecting Falaj water in Oman. This study is a step forward in Oman to employ solar energy in the water and wastewater treatments.

    Keywords: Falaj water, Total coliform bacteria, SODIS, PET bottles
  • M.S. Angaji*, L. Jabalameli, A. Tabatabaee Bafroee Pages 295-304

    Bioluminescence is the production and emission of light by living organisms. This phenomenon occurs widely in different organisms. In fact, light-emitting bacteria are the most abundant and widespread luminescent organisms found in marine, freshwater and terrestrial habitats. In this study, the sea water samples were collected from the Caspian Sea, North of Iran. Luminous colonies were observed after an overnight incubation at 25°C on nutrient sea water complete medium. One luminous bacterium isolated, identified and named as Vibrio sp. isolate Caspian based on biochemical tests and 16S rRNA gene sequencing. Besides, two genes involved in bioluminescence, luxA and luxB were sequenced. Light emission measurement was performed for this bacterium  using luminometer, then compared with a control sample previously isolated from water samples in south of Iran. Vibrio sp. Caspian had a weak light emission in comparison with control sample. Sequencing result of 16S rRNA, luxA, and luxB genes showed that these sequences were highly similar to V. vulnificus. However, there were some difference in both nucleotide and amino acid sequences of luciferase. Phylogenetic analysis based on luciferase nucleotide sequences also showed high degree of relationship between the present tested Vibrio and other related species. In general, the present study revealed the capability of indigenous marine sources of Iran for providing bioluminescent bacteria with different characteristics which may result in finding new luminous systems with various applicable capacities

    Keywords: Bioluminescence, Vibrio, luxA, luxB, Luminometer, 16S rRNA
  • M. Zamani, M. Nikooy*, H. Pourbabaei, R. Naghdi Pages 305-317

    Forest roads are one of the main affecting factors on diversity and composition of plant species. This study aimed to investigate the effects of forest road on composition of tree communities of forests in west of Guilan Province, Iran. Therefore, in two age classes (0-10 and 10-20 years old) of forest roads with five different distances from the road edge, totally, 240 sample plots (150 square meters) were taken by line transect method. The results showed that the relative importance of Fagus orientalis, Quercus castaneifolia and Acer velutinum trees on roads with lower age (0-10 years old) was higher than those with higher age (10-20 years old). The results also indicated that on the newly-constructed roads, the presence of pioneer species (Alnus subcordata and A. cappadocicum) became lower than the other species by moving from the roadside into the forest. In this study, the species importance values of A. subcordata, A. cappadocicum, and A. velutinum decreased from roadside to the forest interior. The results also showed that the Simpson’s diversity and evenness indexin old roads were higher than the young ones. The results of ANOVA analysis showed that by increasing distance from the road, the species diversity and richness declined, while species evenness elevated. The results indicated that there are higher dead trees on the roadside (0-30 and 31-60 m) compared to the inside of forest.

    Keywords: Road age, Diversity, Forest road, SIV
  • N. Dehbandi, R. Izadi Amoli*, R. Oskoueiyan, A. Gholami Pages 319-325

    Staphylococcus aureus is one of the most important causes of infections in hospitals. Although vancomycin is often prescribed for the treatment of methicillin-resistant S. aureus (MRSA), vancomycin-resistant S. aureus (VRSA) isolates remain a major problem in hospitals. In this study, we investigated the prevalence of vancomycin-resistant S. aureus isolates and also vanA gene in these clinical isolates in a hospital in Mazandaran Province, Iran. In this cross-sectional study, a total number of 60 S. aureus samples were identified from different clinical specimens after standard biochemical and microbiological tests. Disk agar diffusion test using Kirby-Bauer method was applied for antibiotics against S. aureus isolates. The presence of vanA gene was investigated in VRSA and intermediate resistance (VISA) isolates by PCR method using specific primers. Over 40% of isolates were resistant to commonly-used antibiotics, including gentamicin (46.67%), ceftazidime (45%) and carbenicillin (43.34%). Only few, however, were sensitive to gentamicin (33.33%) and ceftazidime (35%). Vancomycin was the most effective antibiotic against S. aureus isolates (56.66% sensitivity). Eleven isolates (18.34%) were resistant (VRSA) and 15 isolates (25%) were intermediate resistance (VISA) to vancomycin. Molecular analysis of vanA gene in 11 VRSA and 15 VISA showed that 8 VRSA (72.72%) and 6 VISA (40%) isolates were positive for vanA gene. The incidence of VRSA and VISA strains, as well as the frequency of vanA gene in these isolates are high and emerging in Mazandaran hospitals. There is a need to keep the emergence and spread of these strains to a minimum level.

    Keywords: Clinical isolates, Iran, Staphylococcus aureus, vanA gene, vancomycin-resistant
  • M. Mohammadi, E. Fataei* Pages 327-336

    Providing health conditions, prevention of water pollution and wastewater reuse are needed to select the best wastewater treatment process before designing and implementing, according to regional climatic conditions. the aim of the present study was to evaluate the lagoon and activated sludge wastewater treatment systems using life cycle assessment and ISO14040 standards within four steps. Required data in the study systems were matter and energy inputs, including NH3-N, TP, TN, CL, O2 and electricity, as well as pollutant outputs involving BOD5, COD, SS, NH3-N, TP, TN, CL, CO2, and CH4. The data were obtained from treatment systems of Ardabil (aerated lagoon) and Tabriz (activated sludge), Iran. Some of the data were obtained by calculation and the eco-invent database was used to complete the information required. Data were analyzed by Simapro 8.0.1 software. The results of the study demonstrated that the lagoon system in comparison with the other systems had 100% negative impacts in every effect classes, while the activated sludge system on global warming (6.39%) and photochemical oxidation (7.14%) had the least impact. Therefore, the lagoon system was recognized as the environmentally-harmful system, while the activated sludge as the best wastewater treatment system.

    Keywords: Activated sludge, Aerated lagoon, Effect classes, Environmental impact, Life cycle assessment, Wastewater
  • E. Hajiradkouchak, R. Patimar*, M. Harsij, R. Ghorbani Pages 337-351

    This study aimed to determine age and growth indices of Prussian carp, Carassius gibelio collected a total of 942 specimens on a monthly basis from February through September 2015 in three dam lakes including Golestan, Boostan and Voshmgir and one reservoir named Alakoli from the Southeast Caspian Sea. The largest specimen was a female with 220 mm in total length (TL) and 139.787 g in weight from Voshmgir. The maximum condition factor of the fish increased markedly during late April- August in all areas. Growth pattern was positive allometric in females from Alakoli, while negative allometric in females from Golestan, Boostan and Voshmgir and also in males from Voshmgir. The isometric growth observed in males from Golestan and Boostan as well as from Alakoli. The growth parameters of von Bertalanffy fit to the mean observed total lengths-at-age for each sex separately were estimated as L∞= 378.09 mm, K= 0.12, t0= -0.35 for females, L∞= 309.38 mm, K= 0.17, t0= -0.02 for males, and as L∞= 355.74 mm, K= 0.13, t0= -0.35 for total population in Golestan; L∞= 299.06 mm, K= 0.18, t0= -0.10 for females, L∞= 574.17 mm, K= 0.07, t0= -1.04 for males, and as L∞= 338.43 mm, K= 0.15, t0= -0.34 for total population in Boostan; L∞= 296.37 mm, K= 0.20, t0= -0.20 for females, L∞= 186.23 mm, K= 0.51, t0= -0.42 for males, and as L∞= 302.94 mm, K= 0.19, t0= -0.18 for total population in Voshmgir; and L∞= 347.99 mm, K= 0.04, t0= -0.12 for females, L∞= 530.92 mm, K= 0.01, t0= -0.18 for males, and as L∞= 477.73 mm, K= 0.01, t0= -0.40 for total population in Alakoli. A prolonged spawning period was observed from April through August. Maximum egg diameter and absolute fecundity were 1.39 mm and 72865 oocytes in population inhabiting Voshmgir respectively.

    Keywords: Carassius gibelio, Length-Weight Relationship, VBGF, Reproduction, Southeast Caspian Sea
  • T. Radmard, M. Ajorlo, R. Zeynivand* Pages 353-361

    The size and longevity of soil seed bank in rangeland ecosystem change continuously due to natural and anthropogenic disturbances such as seed mortality, decomposition, consumption by seedivores, fire, and germination. This study aimed to examine the influence of human-induced fire on seeds germination rate in soil seed bank of a semi-arid rangeland. The study was carried out in Darehshahr, southeast of Ilam Province, western Iran in 2016 with two treatments, i.e. burned and unburned sites, in three replications. Soil samples was randomly taken at two different layers of 0-5 and 5-10 cm. Totally, 30 soil samples were taken in each soil layers at each site. Soils were spread on 15 × 20 cm sterilized sand bed and germinated seed was monitored for 3 months. Seedlings were counted every 10 days and then removed from the trays. Diversity and richness of seedling were calculated using respective indices. The Repeated Measure Analysis of Variance was used to compare the diversity and richness of seedlings. The values of the Margalef and Menhinick richness indices in the burned site were 31.12 and 25.15% greater than that in unburned site. In addition, the values of the Simpson’s and also Shannon-Wiener diversity indices in the burned site were 26.6 and 23.27% greater than that in the unburned site, respectively.

    Keywords: Burning, Soil seed bank, Plant diversity
  • F. Hajmoradi*, A. Taleb Beydokhti Pages 363-373

    Stachys inflata Benth. belonging to Lamiaceae, grows in the vicinity of zinc and lead mine around Zehabad village, Qazvin Province, Iran. The aim of this study is to determine how S. inflata is affected by a long-term exposure to zinc and lead pollutants. The focus, here, is on how the meiotic behaviour of pollen mother cells as well as pollen fertility are affected by heavy metal pollutants. ICP-MS analyses of soil and water samples indicated the presence of lead and zinc in a concentration much higher than the recommended standard. The results revealed that soil and water polluted by heavy metals had a significant impeding effect on the division of PMCs in S. inflata. An elevated meiosis abnormality rate, as well as decreases in meiotic index and in pollen fertility were observed compared to the control. The data indicate that this species is not meiotically stable. In general, the pollen mother cells of specimen grown in polluted soil exhibited an increased incidence of chromosome stickiness, B-chromosomes, chromosome bridges, laggard chromosomes, micronucleus, desynapsis, cytomixis and formation of tripolar and pentapolar cells.

    Keywords: Heavy metal, Meiosis abnormality, Pollution, Stacys inflate