Investigating the environmental effects of power plant, petrochemical and refinery on the soil resources of Western Barkhor

Dissertation for M.A. degree

Treatment: Natural Geography (Geomorphology-Hydrology)

Abstract

The increasing population growth followed by the development of industrial activities on the one hand and non-compliance with environmental requirements on the other hand, have caused huge amounts of pollutants to enter the environment in the last few decades. Accumulation of some dangerous heavy elements can limit the use of soil to produce healthy crops for agricultural lands and cause harm to humans and other living beings. Therefore, the current research was conducted with the aim of investigating the contamination of soils exposed to lead and cadmium metals. To carry out the work, first, during the field visit and preliminary surveys of the western Barkhor lands located in the east of the polluting industries, the refinery, petrochemical and Shahid Mohammad Montazeri power plants up to 20 kilometers were selected. Then, soil sampling was done randomly from a depth of 0-10 cm in 41 points in the selected area and in each point in the form of compound sampling. The soil samples were transferred to the laboratory, air-dried and passed through a 2 mm sieve, and some physical and chemical properties and absorbable concentration and total samples were measured. The results showed that the concentration of cadmium in the soils of the region is higher than the permissible limit and these soils are contaminated with cadmium. Examining the map and graphs showed that the amount of cadmium in the soil is related to the longitude, and as the longitude increases and as a result, moving away from the mother industries, the amount of cadmium in the soil increases. Regarding lead, the results showed that the amount of lead in the soils of the region is higher than the permissible limit and the soils of the region are polluted in terms of lead. Examining the map shows that the spatial distribution of lead in the region does not have a specific pattern.

Key words: pollution, soil, heavy metals, cadmium, lead. The health of humans and the environment. Heavy elements are considered among the most important pollutants in the environment, which have been highly considered in the last few decades. The accumulation of heavy elements in the soil, especially in agricultural lands, is a gradual thing and the concentration of heavy elements can reach a level that threatens human food security. Every year, thousands of tons of these elements enter the soil as a result of urban, industrial and agricultural activities. The study of various researchers in the country shows that the intensification of industrial activities in the country on the one hand and non-compliance with environmental issues and standards by some industrial owners on the other hand have caused environmental pollution in some areas of the country.

Soil is one of the important components of the bio-journey of the planet and plays an important role in the health of humans and animals. Soil not only plays an important role in the production of food and clothing, but also has an important effect in maintaining the quality of the environment.  Therefore, soil pollution by chemicals is one of the most important biological issues.

In the past few decades, with the progress of industry, the amount of toxic elements in the soil has increased. Urban and industrial effluents, solid wastes from various urban, industrial and agricultural activities, all kinds of fertilizers and chemical poisons are important sources of soil pollution with toxic elements. which have been strongly considered in the last few decades.                         

Polluting substances entering the environment are either of natural origin or are created as a result of human actions. Most of the natural pollutants are not concentrated in one place and decompose to a harmless extent. On the contrary, the most acute type of human pollution occurs near cities or industrial areas, that is, where pollutants are concentrated in air, water and soil in a dense and low volume. In addition, many human pollutants are chemical compounds that do not break down in natural ways. Therefore, any city or point that is located in the vicinity of a polluting economic factor. Undoubtedly, it has been affected and its effects can be seen in social, economic and environmental aspects. Pollution of the environment in every part (water, soil, air and plants) is a problem whose harmful effects will be evident in the long term. In fact, soil is the most sensitive and vital part of the earth. In addition to the role they play in the continuation of life, soils have also left a major impact on the evolution and even the origin of life.Of course, industrial activities and as a result of soil pollution have irreparable effects on our life, and knowing the polluting sources and preventing soil pollution makes possible the optimal use of resources and minimizes environmental risks. Considering the importance of soil as an important and basic resource in the production of society's wealth and in the development and health plans of society, we must pay enough attention to the soil health and protection program and try to avoid pollution or preserve its natural quality. This economic boom has certainly caused the creation of significant environmental effects, which is important to investigate. One of the most important environmental effects of these industries is soil pollution through the entry of solid and liquid waste into the soil, as well as the deposition of suspended particles from these industries on the surface of the soil and plants of the region and being absorbed into the soil. Therefore, considering the importance of this project, this project was carried out to investigate the level of contamination of the soil in the region with dangerous heavy elements, cadmium and lead.   

1-2 Objectives and necessity of research

Following the development of industries in a place, environmental pollution also increases. The purpose of investigating and evaluating the effects of dust industries is to know the level of pollution and find ways to control it. The present research was also carried out in order to investigate the effects of the western Barkhor industries (power plants, refineries and petrochemicals) on the soil resources of this region with the following objectives.

Investigation of the degree of contamination of the western Barkhor soil in terms of heavy metals cadmium and lead

Investigating the distribution of the concentration of cadmium and lead elements in the soil of the region and the extent of the influence of the existing industries in the region on this distribution

1-3 Research background

Rahmani (1374) in a study entitled Esfahan Mobarakeh Steel Company's Effluent Quality and Its Effects on the Land under Moi Cultivation has come to the conclusion that the soils irrigated by industrial effluent have an absorbable concentration of heavy elements beyond the control soil and the total concentration of heavy elements is within the critical concentration range of these elements in the soil. Regarding the spatial correlation of heavy metals, all the studied elements have a moderate correlation. Golchin et al. (1385) in a research titled "Investigation of the effect of Zanjan lead and zinc factories on the contamination of crops and garden crops with heavy metals" have come to the conclusion that the concentration of lead and cadmium in plant samples near the factory is high and worrisome, and the most contamination of lead and cadmium was observed in fodder, which is used by livestock and is also harmful to humans.

Emami et al. (2005) in a research entitled investigation of the concentration of cadmium, lead and zinc in the profile of a type of calcareous loam soil after washing with a solution of these elements, have come to the conclusion that the concentration of cadmium in different depths of the soil had significant differences and only from a depth of 14 to 30 cm no significant difference was observed between different depths. It seems that the cause of concentration distribution is the way of filling the soil column because it is not possible to compress all soil layers equally, as a result some layers become denser than other layers. This causes the layers that are more compressed due to the lower speed of water and the longer contact of the solution with the solid phase, to absorb a larger amount of heavy elements. Khosravi et al. (2007) modeled the spatial distribution of total lead and total cadmium in the surface soil of Isfahan city by discontinuous kriging method and using ARC GIS92 software. The statistical analysis of the data of this study showed that there was a significant positive correlation between the amount of cadmium and lead at the level of 5%, but there was no significant correlation with other parameters.

Amini et al. (2005) used index kriging for 255 surface soil samples (0-20 cm) to prepare a map of cadmium and lead contamination in the soils of Isfahan region with an area of ??6800 km. They compared the obtained concentrations with the reference value of Switzerland, in more than 80% of the samples cadmium was higher than the reference value and in only 2% of the samples the amount of lead was higher than the reference value. In this study, using kriging, the probability index maps of cadmium and lead concentrations exceeding the desired threshold were determined. The results showed that the probability of contamination by cadmium is much larger (> 95%), while this probability is small (> 5%) for lead.