JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2006 | Volume:- | Issue:27|Papers Count:10

Due to its adverse effects on the activity and cellular structure of microorganism's high salt concentration significantly reduce the efficiency of biological treatment processes of saline wastewater.Synthetic wastewater composed of diluted molasses, urea, salts of buffer phosphate and various concentrations of salt (0.7- 2.5% NaCl), was treated in a Moving Bed Biofilm Reactor unit (MBBR).In order to start up, the recycled sludge flow of activated sludge culture obtained from the wastewater treatment plant was added (used as inoculums) to MBBR reactors that 50% of the reactor's volume were filled with the carrier elements, shaped like small corrugated cylinders, are made of polyethylene.The effects of important process variables such as COD loading rate (Ls), hydraulic loading rate (Q/A) and salt concentration on the performance of the system were investigated. An empirical mathematical model describes the system's performance in various salt concentrations and COD loading rates separately. Using the experimental data, the constants of models were determined.The obtained equations can be used in MBBRs systems under similar conditions and with in the ranges tested for the parameters.

This study has been carried out to evaluate the existing noise pollution in schools of central karaj situated at 35 Km west of Tehran. The Leq30 min was measured in classes and the noise level was analyzed in one-octave band central frequencies to calculate the preferred noise criteria. A questionnaire was filled by teachers in order to evaluate the probable subjective effects of noise pollution.The results indicated that the mean value of PNC and Leq 30 min A was 55.6dB and 51.8dBA, respectively, which were higher than the recommended permissible values (both 35 dB (A)).This may be due to the increased numbers of schoolchildren, oldness of school buildings, presence of schools in areas with heavy traffic, e g, along busy streets and high ways, construction activities, and lack of sports hall in schools. Noise pollution in non-profit schools was 4dBA less than the stste schools. It might be due to the fact that the private schools mostly had new buildings, fewer students than the state school, and sports hall for the children to exercise.According to an open-ended questionnaire, 32% of teachers considered noise pollution as the main problem while teaching at school, And 47% of them believed that it could be harmful to the students and might decrease their motivation.

In this survey, residue of Dimethoate phosphate insecticide upon the cucumber product (that it is the most important truck farming in the Fars province) was measured in 2004. In this study from TLC Scanner method was used. The area divided to subdivisions included: Kor River, Korsivand River and Sivand sub-basin. In the each of these subdivisions, 6 places were selected for sampling. And from cucumbers of each place in as exhibit to market, the sampling carried out into accidental. The obtained results of examinations, war presented that: in 66.7% of samples, measure of Dimethoate residue was upward of standard. In the 22.2% of samples, the residue was less than of standard, but it was near of it and in the tolerance records. In the 11.1% of yielded samples, didn't watch Dimethoate insecticide.By comparison of obtained results from residue of Dimethoate insecticide in cucumber in these 3 basins, with use of Kurskal-wallis method, didn't watch significant difference and comparison of obtained results, the commodities in selected areas in 3 subdivision with limits by T-test, as most of areas, P>0.05 was and also didn't watch signficant difference.

In this study, the effect of various NiCl2 treatments (0, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450,500mM) on seed germination in Brassica napus cultivars (Hyola and PF) has been investigated.The results show that an increase in the nickel concentration causes a decrease in the seed germination in Hyola, which was greater than that in PF. Therefore, it is concluded that the toxicity of nickel is probably one of biochemical mechanisms influencing the response of these cultivars to the nickel stress.Also, the effect of various NiCl2 treatments (0, 100, 300, 500mM) at rosette stage of two Brassica napus cultivars on the proline metabolism, catalase and peroxidase activity of leaves and root was investigated under the greenhouse conditions. The two types of cultivars (PF and Hyola) were highly sensitive to NiCl2 treatments. In general, in response to the heavy metal treatments, proline concentration, catalase and peroxidase activity in both varieties are increased. Therefore, it seems that the heavy metal stress could induce significant changes in proline and catalase and peroxidase activity both in the leaves and the root during the rosette stage through these cultivars.

Planktonic blooming is one of the aspects of biological pollution in marine environment. Due to the harmful effects of this natural phenomenon on the aquatic resources, marine ecosystems and human beings caused by consuming polluted aquatic creatures or by contact with polluted water, another effect of this phenomenon, i, e., mutagenicity and carcinogenicity of planktonic blooming, was investigated. This study was conducted using Ames test with Salmonella typhimurium strain TA97 and microsome. In this research, a sample of red tide (chlamydomonas sp) in the two phases of supernatant and mass was added separately to the minimal agar medium Salmonella typhimurium strain TA97. For comparison, sodium aside and distilled water were used as positive and negative controls, respectively. Counting the colonies and comparing them with those of negative control, the impact of red tide mutagenicity in the supernatant phase was observed. Such an impact was not observed in the mass phase.Carcinogencity microsome of rat liver produced under sterile conditions was added to the minimal agar medium having plank tonic blooming sample and strain TA97. The impact of mutagenicity was not observed when the numbers of produced colonies in the sample, the positive control and the negative control were compared.

Polycyclic aromatic hydrocarbons (PAHs) are among the most important pollutant. The study done at the Ecological Academy of Caspian Sea study indicated that the concentration of naphthalene in different regions of Caspian Sea was more than other PAHs.In this research, different species of Pseudomonas bacteria capable of naphthalene degradation were isolated from the southeastern Caspian waters. The Samples were taken from the two stations in Amirabad and Noshar ports and were cultured in minersl basal medium having naphthalene (as sole carbon source); then, they were sub-cultured in cetrimid agar.Biochemical tests and differential medium were used for the identification of Pseudomonas spp. Four different Pseudomonas including P.putida; P. aeruginosa, Pjluorescens, and P.saccharophila were isolated. P. putida and saccharophila had the highest and lowest frequencies in the two stations, respectively.The rate of naphthalene degradation was shown to be dependent on different factors such as the density of degrader bacteria, oxygen, temperature, pH, salinity and nutrients. The concentration of naphthalene for optimal degradation was 107-108 cfu/ml P.putida was the dominant bacterium for naphthalene degradation.

"Rafetus euphraticus" is a medium-sized trionychid species thought to be most closely related to the Asian species "Rafetus swinhoe". It is found only in the Euphrates and Tigris rivers and their tributaries of Turkey, Syria, Iraq, and Iran. In Iran, it is found in the rivers of Khuzestan province. Mesopotamian soft-shell turtle is listed as "endangered" in the IUCN Red List of threatened species. Unfortunately, in Iran this turtle is not protected by low.In the course of this study (February 2002 - June 2005), 14 visits were made to the habitats of the specie along the Karkhe, Dez and Karoon rivers and their tributaries in Khuzestan province. During these visits 20 specimens were observed and habitats characteristics of observation sites were recorded. Based on these variables, the habitats were ranked from 1 (poor) to 4 (excellent) which are reported in the paper. Also, 5 specimens were taken and their morph metric characteristic were measured and reported.According to the findings of the study, habitat destruction, pollution and poaching are the main threatening factors. To protect this species, more information is needed about biology, habitats, and the relationship between the local communities and the species.

This article investigates the countries' situation according to maritime political geography. In this view, countries are divided into three groups. The purpose of this study is to present a clear image of the geopolitical situation of the land locked states, those neigh boring the seas, and those close to the oceans.Analyzing the information and the documents obtained about the countries' efforts and struggles aimed at sovereignty over the different parts of the seas, it can be argued that the claims of powerful and developing states are different in this regard and that each of them is seeking its interests in the seas through legal means.