JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2007 | Volume:8 | Issue:4 (31)|Papers Count:12

Recycling is one the widely used alternatives in the solid waste management system. For recycling plans, recognizing the quality and the quantity of the solid waste is quite necessary. All over the world, especially in the developed countries, a lot has been done in this regard. But in Iran, no comprehensive survey about the potential of recycling in urban areas has been done.For the first time, this study was implemented in 2003 for all provinces including Sistan and Baloochestan. Three cities of Zahedan, Iranshahr and Chabahar were chosen for study. Sampling and examinations were done according to the standard methods obtained from governmental agencies and the related literature.The results show that every person produces 504 g solid waste per day with the moisture and density of 25.5% and 182.8 kg/m3, respectively. Solid waste consists of 53% garbage. C/N ratio, 22, makes it suitable for composting. Other important constituents are plastic and paper with 10.8% and 10.5%, respectively.

This study considers oil trajectory and fate models in the Persian Gulf, which have been studied in Iran and other countries. The governing equations and the main physical parameters are determined in processes affecting an oil slick. Schmidt and Richardson numbers are used in mass transfer coefficient for evaporation and vertical diffusion coefficient, respectively. The main governing equations of the movement of the oil slick are Navier-Stokes equation, continuity equation and concentration transport equation. The effective source term (mass balance), which includes the evaporation, dissolution, and vertical dispersion, as well as the shoreline and bed deposition and also vertical and horizontal diffusion coefficients are important factors in the concentration transport equation. Based on studies, an ideal two-dimensional trajectory and fate model simulates the movement of the oil slick. The characteristic of an ideal three-dimensional oil fate model simulates the distribution of oil particle concentration in the water column. This model is proposed for the prediction of oil spill movement in the Persian Gulf. The model has been run for the region between the Khark Island and the Bushehr Port. The results show consistency with other similar studies.

Today, the numerous consequences of air pollution, especially those related to people's health such as respiratory, heart and nervous system diseases, have made the monitoring and control of air quality an unavoidable issue and the main concern in all societies.In this study, due to the fact that Tehran>s air is much polluted, the city>s air quality index for 5 major air pollutants - 03, PM10, CO, SO2, and NO2 - in 2004 was calculated.The Air Quality Index showed that 262 days in the year under study, air pollution had been more than the accepted standard level (i.e., AQI= 100). In 12 percent of the days, the air quality was rated as unhealthy and in 5 percent of the days as hazardous, with carbon monoxide as the cause of pollution in 83% of the cases. It should also be mentioned that the three months of August, September and October of 2004 were the most polluted with average indices of 190, 185, and 188 on the AQI scale. Comparing the results of this study with the results of the studies done in the previous years, it can be concluded that Tehran>s air quality has not improved much and is still very dangerous for people, specially the sensitive groups.

Due to the modern life and human activities, air pollution has now become a main concern in Tehran and other large cities and may lead to important environmental impacts. Since traffic plays a major role in polluting the air of Tehran, public transportation as the best option in the world is essential to prevent and control air pollution. Subway as a fast, safe, and reliable means of public transportation has the fewest environmental impacts. Now, Tehran subway plays a significant role in reducing the city>s air pollution. In this study, the environmental impacts of 4 inter-station ventilation systems in the northern half of line one of Tehran subway were studied. To this end, the carbon monoxide, relative humidity, air velocity, and temperature in 4 different stations were measured and compared to the similar parameters measured by the environmental monitoring stations located close to the subway stations of this study. The results show that the average carbon monoxide concentration level at the subway stations are 30% to 40% lower than the average carbon monoxide concentration levels measured by environmental monitoring stations located close to the subway stations. The average carbon monoxide concentration levels measured at the subway stations are less than clean air criterion (.9ppm) and the average daily temperature of air exiting from ventilation stations is 21-27 degrees centigrade. This is 10 degrees lower than the average daily air temperature in Tehran in the hot months of July and August. The average daily relative humidity of air exiting from ventilation stations is 40-50 % mainly due to the nonstop and proper operation of the subway ventilation system. This is 15 %more than the average daily relative humidity of Tehran.The results also show that the air velocity at the ventilation systems is independent of the city's air velocity changes.This study shows that the ventilation system of Tehran subway can be considered as an appropriate system under normal conditions. It not only reduces the air pollution but also increases the quality of air around the subway stations.

In this study, the acute toxicity of the heavy metal of cobalt on Cyprinus carpio was determined in the laboratory of the Science and Research Branch, Islamic Azad University, in 1384.The experimental investigation took 96 hours using the O. E. C. D. guidelines. Fishes were divided randomly into eight groups of ten fishes each. The average length and weight of the fishes were 9±1.5cm and 10.125±2.19 gr, respectively. A group was chosen as the control group and seven groups were placed under concentrations of 50, 100, 200, 300, 400, 500, and 600 mg/Lit cobalt. All important physicochemical parameters of water including pH, dissolved oxygen, hardness, temperature, and conductivity, total alkalinity, phosphate, nitrate and nitrite were measured. All the examinations were done with two replicates. The data were analized using probit analysis with software spss. The 96h LC50 values of cobalt chloride for Cyprinus carpio with two replicates were values of 328 and 327 mg/Lit,. respectively.

In this study, hatchability and nutritional value of Artemia urmiana's Nauplii, and the effects of temperature on these factors were evaluated. The experiments were conducted factorially with two levels of temperatures (25 and 30oc) in triplicate random groups. Hatchability of cysts at these temperatures were determined. To determine the biochemical composition of their body, Naupliies were hatched in five-liter bottles and harvested after 24 hours. Dry weight, protein, lipid, carbohydrate, ash, caloric content, and fatty acid compositions of Nauplii's were determined at these two temperatures. The individual dry weight and the individual biochemical composition of Nauplii were also determined.The results showed that the hatching percentage and hatching efficiency increased with an increase in both temperature and time. For the hatching percentage, the increase was significant (p<0.05). The nutritional value of Naupliies decreased slightly at higher temperatures in most cases, but the change was not found significant (p>0.05). Based on the results of the study, a temperature of 300 c is recommended for cysts' hatching; at such a temperature, not only hatchability increases, but the nutritional value is also preserved.

Khoshk River which flows through Shiraz and pours into Maharloo Lake is a seasonal river. Different types of wastewater (domestic, business, industrial, and agricultural wastewater) run into this river.To examine the quality of the river>s water and the pollution caused by heavy metals (Cadmium, Zinc, Copper, Iron and Nickel), six stations were established and samples were taken from the water in 2005. Also, in the spring of 2005, some samples were taken from the products of the nearby farms and the rate of heavy metals found in them was measured. The average concentration of heavy metals in the rivers water was compared with the maximum allowable figures for drinking water, surface waters, irrigation, and aquatic creatures, using a t-student test (with a confidence level of 95%).The results showed that the water in station one (Moali Abad bridge) lacks heavy metals and is completely safe for any use. However, the water in the stations two (Namazi bridge), three (Parking bridge), four (Salman bridge), and five (Sharif Abad bridge) is not suitable for drinking, irrigation, and aquatic creatures, but it is safe as surface water. The water in station six (end of Kharchool) is not suitable for drinking and aquatic creatures, but it can be used for irrigation and is also safe as surface water.Regarding the farming products, it can be said that some of them contain heavy metals but only the rate of copper in all the plants and iron in only one case was more than the maximum allowable figures.

Occupational injuries and fatalities occur every day in workplaces. They often occur because employees are not trained on the proper job procedures. JSA, a consistent and systematic approach, can help identify and assess risks associated with hazardous job and develop control measures.In this approach, jobs are broken down into theirs steps, potential hazards associated with each step are identified and assessed, and then proper control measures are recommended. This research was conducted in a production factory where 45 hazards were identified and assessed through JSA, of which 14 were high-risk, 28 moderate-risk and 3 low-risk hazards.To remove or reduce the risks, certain control measures are recommended, among which training the workers and supervising their performance continuously are the most important ones.

Japan's rapid economic growth during the 1960s caused water pollution problems to spread and intensify. In 1967, the government of Japan enacted the "Basic Law for Environmental Pollution Control" to promote comprehensive countermeasures against the various forms of environmental pollution. Environmental Quality Standards (EQS) for water pollutants are target levels for water quality that are to be achieved and maintained in public waters. These standards are established to achieve two major goals: protection of human health and conservation of the living environment. The first goal is met by setting uniform national standards applicable to all public waters. However, the second goal is achieved by classifying rivers, lakes, reservoirs, and coastal waters based on water usage and by establishing EQS values for each class. In March 1993, the Environment Agency broadened and strengthened the EQS for protecting human health. As a result, EQS for a total of forty-eight substances including cadmium and cyanide are now available. The main aim of this paper is to review water quality standards in Japan and the results can be useful for the developing countries such as Iran.

The City of Rey with a population of 1 million suffers from water crisis. Among different water resources, groundwater has a major role in supplying 40 to 50 percent of the city's drinking water. Therefore, its contamination must be studied both as a regional issue and as a threat to the social health.In this study, nitrate is considered as the best index showing the groundwater contamination, especially due to the anthropogenic activities in the area. In studying the nitrate contamination of the groundwater, there were several problems such as the lack of proper data and the vastness of the case-study area.This study focuses on contamination sources, saturated zones, and the quantity of nitrate discharged into the groundwater .The groundwater concentration in central and eastern parts of the city is 65 ppm.The mathematical model (MT3D) makes it possible to predict the groundwater quality. The simulation results show that the concentration of nitrate will increase in the central and eastern regions, but a sewage collection network can reduce the concentration of nitrate by 30 ppm.