نشریه علوم محیطی
سال نهم شماره 1 (پیاپی 33، پاییز 1390)

Despite the increasing importance of water conservation across the world, there is very little understanding about the psychosocial variables that help predict people’s water conservational behaviour. This study used a modified model of the Theory of Planned Behaviour (TPB), including the additional variables of moral norms, self-identity and subjective myths of the nature as general beliefs, to predict intentions and behaviour regarding water conservation through a random sample of agricultural professionals (n= 80) using the survey method in Bushehr Province. Findings revealed that the modified theory of TPB can explain intention and behaviour regarding water conservation. Multiple regression analysis showed that moral norms, perceived behavioural control and risk perception can predict 68 percent of variances in water conservational intention, while subjective norms and perceived behavioural control can predict 49 percent of variances in water conservational intention based on the original TPB model. Therefore, those agricultural professionals who perceived a greater normative and commitment feeling regarding water conservational behaviour had a higher level of intention to engage in such behaviours and the significance of perceived behaviour control revealed that professionals did not have complete volition in their water conservational behaviour. Furthermore, myths of nature can predict about 39 percent, 20 percent and 28 percent of variances in attitude, moral norms and risk perception regarding water conservation.

«Information», «persuasion», «dialogue» and «consensus building» were taken as the possible communication strategies to facilitate Sustainable Animal Husbandry (SAH) in rural areas of Kohgilooyeh County, Southwestern Iran. Also, various different aspects of SAH attributes were considered which include organizational sustainability, sustainable programs, use of proper media, focusing on target customers, and suitable monitoring- evaluation systems. The study was carried out using Evidential Reasoning, a Multiple Attribute Decision Making (MADM) technique, to choose the most appropriate communication strategy for SAH in the study area. Results indicated that, generally, «dialogue» was the first communication strategy that should be chosen for SAH. Of course, it was revealed that communication strategies would vary depending on the attributes of sustainability. More detailed results, especially about how to choose media based on the communication strategy, are presented in the body of the paper.

Lag time is a parameter that appears often in theoretical and conceptual models associated with river basin. The river basin lag time is an important factor in linear modeling of river basin response. Generally, all hydrologic analyses require at least one of the time parameters of river basin and, in the majority of cases, time of concentration or lag time are used. In this research, storm data from 6 stations in the North Karoon river basin (in Iran) were analyzed. From this analysis, 23 events were selected. Then, in one experimental sub-basin located in this river basin, the lag time was calculated using field method. In this method, performed in the Darehbeed-Samsami study area, lag time was computed from a hydrograph generated by discharge measurement of a triangular scaled spillway. After that, 23 events were divided into two groups, including, one for a newly developed empirical model (70 percent) and another for validation of this model (30 percent). The results obtained from this research based on coefficient of determination (R2), root mean square error (RMSE) and relative error (%RE) statistical measures showed that the agreement between the computed(from new empirical model) and measured data is good.

Metal concentrations in commercial and non-commercial fish were surveyed to assess risks of fish consumption to human health and importantly, assess contamination in the food chain. In this study, lead (Pb), Zinc (Zn) and Copper (Cu) concentrations were determined in muscle and skin tissues of wild and cultured Cyprinus carpio (common carp) from the southeastern Caspian Sea area and a nearby fish farm in November 2007. Metal concentrations were determined by atomic absorption. Pb and Cu concentrations in all of the samples were below detection limits and there were no statistically significant differences of Zn concentrations in muscle and skin tissue between wild and cultured carp. But Zn concentrations in the skin tissue were significantly higher than in muscle tissue in both groups; this suggests that more studies about skin tissue as a site of bioaccumulation are necessary. None of the concentrations exceeded WHO safety standards. Our results have suggested that heavy metal contents in carp are negligible and that its consumption should pose no health problems for consumers of either the wild or farmed fish.

Soil salinity expansion is an environmental challenge particularly in arid and semi arid regions. In order to evaluate the progressing extent of soil salinity in relation with natural and human-induced conditions, a study was conducted using the Landsat TM imagery. The present study was conducted in the Garmsar area to the East of Tehran. A total of 288 soil samples were analyzed to determine the relationship between the spectral reflectance and Electrical Conductivity (EC), as salinity indicator. Multiple regression analysis and Ordinary Least Square regression (OLS) were used to examine the relationships between EC and derived spectral to generate several models. In the case of derived spectral, mid-infrared band (TM Band-7), visible band (Band-1), Tasseled cap3 (Wetness index) and PCA2 (Principal Component Analysis) were found to be most correlated with the observed EC values of the surface layer of the soil, at 99% confidence level. The accuracy of the prediction model was tested using a validation set of 52 soil samples in Eyvanekey plain, close to study area where the environmental circumstance consist of similar properties. RMSE and MAE were used to evaluate the performance of the map prediction quality. Results showed that the appropriate model could predict the soil salinity with precision of 4.1 and 0.49 dS m-1, respectively. The predicted salinity ranged from 0dS/m to 110dS/m. Therefore, the EC estimations were suitable to generate soil salinity map. Sensitivity analysis was tested on applied parameters that showed Band-1 and Band-7 were 3 and 2 times more than sensitive rather than other parameters respectively. The results are promising and certainly useful for soil salinity prediction.

Extraction of water from underground sources is on the increase, especially from basins stored by non-strengthened alluvium, sediments and from shallow areas of the sea. This results in sinking on the surface and leads to ground subsidence. In recent years, the Minab Plain, like many areas of Iran has faced drought, which has led to more uptake of subterranean water; this lowers the underground water level and results in sinking which appears on the surface as a sinkhole following subsidence. A field study of this sinking phenomenon involves the following procedure: Firstly, the analysis of the drought occurrences in the area including features of water table, sediment and bedrock. Secondly, the consideration of exploitation of the subsurface water; and finally, identification of the different forms of subsidence in the area from the information acquired above. Statistics from the Sheikh Abad rain-gauge station (covering a period of 27 years) were used for this investigation. Data on precipitation are presented with the decimal method and the standard precipitation index, an index that shows any decrease of climatic rainfall in the area. This data shows that in recent decades there has been less than normal rainfall and that the area has undergone a period of intense drought. In most parts of the plain new alluvium was formed at a depth of 2-3 meters from the surface, the sediment of which often constitutes large grains, which gradually changed to form finer sediment in the form of sand, silt and clay containing salt-water. Therefore, it can be said that with increasing depth, the sediments become tinier (smaller) with an increase in salinity. All of the wells in this area have settled on washed silt sediment and have a high density around the rivers of the Minab area. Because of recent droughts and the drying up of the water supply canals of Minab dam, the digging of wells has increased from 164 in 2002 to a current figure of 607 dug wells. Critical factors related to occurrences of subsidence, are that the existing alluvium covering with the varying thickness up to 150 meters has formed small-grain, silt clay-silt loam soil, which has increased surface subsidence following extraction of underground water over the past two decades.

This study was undertaken to determine the possibility of using lignocellulosic material as reinforcing filler in wood plastic composite (WPC). Recycled high density polyethylene was used as the matrix and rice-husk flour as the reinforcing filler to prepare a wood-plastic composite. WPC specimens of 45×25×1.6 cm were manufactured using a hot press (T: 200°C, P: 160 bar and t: 7 min). In the sample preparation, high density polyethylene (HDPE) was added at two loadings (40%, 60%) and WPC densities of 0.7 and 0.8 g/cm3 were tested. In order to examine the compatibility of rice husk with the polymer, maleic anhydride grafted polyethylene (MAPE) was used as a coupling agent and was a variable factor (0%, 3% and 6%). Twelve treatment groups were considered with 3 replicates per treatment, so a total of 36 groups were tested. Water absorption and the thickness of the swelling were measured after 2 and 24 hours. The mechanical properties of the specimens were determined, namely the bending strength, modulus of elasticity and internal bonding strength. According to the results, the optimum treatment with the best physical and mechanical properties was WPC at 0.8 g/cm3 density, 60% HDPE and 6% coupling agent. Results showed that with an increased content of coupling agent (MAPE), the physical and mechanical properties improved. Having significant differences between the data for water absorption and the thickness of the swelling, the optimum treatment also showed acceptable levels.

The analysis of income effect on environmental quality has been an important debate in the 1990. Several papers have used different approaches for an analysis of the relationship between income and environmental quality. Also, many of these papers have employed different measures of pollutants and income. The U inverse relationship between income and the level of pollution has been confirmed in many papers. In this paper, the relationship between pollution and income has been extracted by means of their microeconomic foundations. The U inverse relationship between the pollution generation (CO2) and GDP per unit of energy use has been tested for selected OECD and OPEC countries in 1980-2003 and 1985-2003. The results of this paper show that the economic structure of the group of countries selected and the period of time had a major role to play in rejection or acceptance of the Environmental Kuznet’s Curve hypothesis. Also, the elasticity of the problem of pollution and GDP per unit of energy use for selected OPEC countries is almost two times that of the OECD countries.