People are putting the planet Earth into great difficulties, with their irresponsible way of living. During the 20th century, the world increased its consumption of fossil fuels 12 times and used 34 times more material resources. According to futurists, demand for food, animal feed and fiber can increase by 70% by 2050. If we continue to use resources at the current rate of utilization, we will need more than two planets to sustain us. Soil is becoming increasingly polluted, because of rapid population growth and accelerated economic development,and is increasingly being exploited both for food production and as a source of basic raw materials. At the same time, a large part of the waste matter that is generated in numerous human activities is deposited on the soil. All this affects the normal functioning of the soil and causes pollution and various forms of damage.
Contamination of the soil may result in its degradation, destruction, or temporary or permanent complete exclusion of the soil from function. Pollutants found on the soil surface in the inner layers can be the product of natural and human activities on Earth. Natural sources of pollution include: ore deposits, mineralization, rocks of specific composition, forest fires, volcanoes, earthquakes, storms and sandstorms, erosion, storm rains, floods. Anthropogenic sources of pollution include: mining, industry, agriculture, urbanization and communal activities, traffic and transport, forest fires caused by humans, floods, erosion. When pollutants reach the soil in any of these ways, their further fate depends on a number of physical, chemical and biological factors whose impacts are intertwined. As a consequence of various causes of pollution, the following processes can be distinguished:
- biological contamination (infection) means bringing into the soil various parasites, viruses, bacteria, fungi, etc., which reside in the soil and can directly or indirectly infect animals and humans through plants;
- chemical contamination means bringing into the soil, various harmful organic and inorganic substances in various forms (solid, liquid, gaseous), such as: heavy metals, organic pollutants, radionuclides, pesticides, mineral fertilizers, etc. The highest contamination usually occurs in the areas of industrial zones and in close proximity to roads and waste dumps.
- anthropogenic degradation represents damaging the soil when in regular use in a crop production. It arises as a result of irrational soil use, and is manifested through: damage to soil structure, compaction, reduction of physiological depth, occurrence of surface and furrow erosion, soilslides and reduction of soil fertility.
It is estimated, that 275 hectares of farmland in the European Union are "destroyed" every day.[1] Most of the world's land is in satisfactory, poor or extremely poor condition. For example, in EU countries, the situation is as follows: in Italy, about 45 percent of the coast is paved, and for Spain the particular problem is soil drainage. On the other hand, there is significant soil erosion in Eastern European countries, so about 35 percent of Podzol's soil is excessively acidic, and 40 percent of Lithuanian soil has a high concentration of heavy metals. Approximately 45% of the land in Europe has very low organic matter content (0 - 2% organic carbon)[2] and 45% of the land has a medium level (2 - 6%). The problem is particularly highlighted in the countries of southern Europe, but also in parts of France, Britain, Germany and Sweden.
In the first decade of the 21st century, the Ministry of Environment and Water of the Republic of Bulgaria implemented a program of monitoring of soil pollution that fully meets the requirements of the EC (European Commission) and EEA (European Environment Agency), with good practices in many European countries, as well as with national legislation. The monitoring program is organized in 3 levels:
- Level I refers to the assessment of soil conditions according to the following indicators: content of 9 heavy metals and metalloids, total nitrogen, phosphorus, organic carbon, active soil reaction (pH), electrical conductivity, nitric nitrogen, total carbon and persistent organic pollutants;
- Level II is oriented towards regional manifestations of degradation processes, such as acidification, salinization and erosion, soil compaction (Corine Soil Cover project);
- Level III is aimed at identifying and inventorying (listing) local soil pollution.
The periodic monitoring and listing is different depending on the monitored processes. Tests of soil samples are carried out in 15 regional EEA accredited laboratories (Executive Environmental Agency).
In the project area, the impact of anthropogenic factor on soil pollution is particularly highlighted through irregular tillage, poor selection of agricultural crops and plantations, forcing crops that are cultivated on sloping terrain, deforestation and other factors that have led to erosive processes. Erosion destroys large areas of the most fertile land, decreases its productive capacity, and gradually degrades climatic conditions and threatens the environment.
[1] www.agroklub.rs:EU lose 275 acres of farmland every day!?
[2] www. poljoprivreda.info: Karolić, R.: Plowing land (I): Agricultural soil degradation in the European Union.
2.1 Factors of environmental hazards that are affecting soil
Quality soil is essential for agriculture and the food production system, and it is vital for the future of food and agriculture. Any destruction of soil in any form threatens the future of food sources as well as humanity.
Soil degradation can occur in many forms as a result of intensification of various human activities, such as: erosion,acidification, compactness, salinization, soil desertification.
Erosion is the most widespread and most severe form of soil degradation. Wind or water, with their kinetic energy, move the surface particles of the earth from one place to another.
Erosion was once a natural process in which the amount of soil removed was equal to the amount of newly created soil and was used to rejuvenate the soil. In recent times, erosion has been accelerated due to intensive deforestation, vegetation destruction, uncontrolled grazing and inadequate tillage. The main reason why the area of arable soil is being lost and reduced is, first of all, erosion, due to which virtually 25,000 hectares are lost annually only in Serbia, while in the world it is considered that erosion consumes more than 50 million hectares annually. Combating erosion and torrential floods should be taken seriously, as they are very dangerous. Serbia is one of the countries that are very vulnerable to erosion.
Compactness of soil often occurs due to the misuse of various agricultural machines during the preparation of soil for plant cultivation.
The soil loses porosity, decreases the amount of water and air in it, compromises biodiversity and therefore the quality of the soil.
Salinization is the process of water passing across the soil over a long period of time with a high concentration of salt and it leads to its accumulation after evaporation of water.
High concentrations of soil salts adversely affect plant development.
Soil desertion is a consequence of the interaction of unpredictable climatic variations and inappropriate soil use, resulting in the disappearance or damage to the biological potential of the soil.
Over time, due to the irreversibility of the process, the soil is transformed into desert type of soil.
Acidification occurs as a result of overuse of nitrogen fertilizers in agriculture, soil drying and aerial pollution, and this natural process has been accelerated lately. Over time, acidification leads to a decrease in soil fertility and a change in its buffering capacity.
In recent years, the so-called "acid rains" have emerged as a very dangerous enemy of the soil. In recent years, it is estimated that over 10 million hectares have been drenched in Europe and North America. By definition, acid rain is an atmospheric acid precipitation in the form of rain. An even more accurate definition is that acidic rainfall is a rainfall that has a higher acidity (less pH) than normal rainfall in unpolluted regions of Earth. The term acidic precipitate covers all acidic precipitation which engulfs gases, particles as well as the liquid phase so that all acidic substances from the atmosphere are contained in the acidic precipitate. That is why the trivial name of "acid rain" is increasingly being replaced by a much more regular "atmospheric precipitate" that covers all acidic substances as well as any other pollutants found in the atmosphere.
Thus, for example, measurements of rainwater acidity in North America reached pH 3, and the lowest value for rainwater pH in the US ever measured was 2.1 in the northern parts of the United States in 1964. In Europe, the lowest value ever measured was pH 2.4 in Scotland in 1974.[1] In Serbia, the acidity of rain in Bor also reaches very low pH values between 2 and 3. By the way, unpolluted rain is also acidic, but its pH value is about 5.6.
[1] https://www.chem.bg.ac.rs: Gržetić, I.: Atmospheric precipitate and acid rains
2.2 Soil pollutants: causes and effects in the short, medium and long term
Unlike other environmental media (water, air), soil is static and has a high capacity to accept large amounts of pollutants that remain in it for many years so that the effects of pollution are long hidden and some trigger is needed to move pollutants from the soil to other environmental media. The largest sources of soil pollution today are industry, households and agricultural production.
Heavy metals are naturally found in soil, but lately their concentration in the soil have increased rapidly due to many different human activities. In the soil, metals are usually connected to mineral particles from which they are released under certain conditions (eg with acidification of the soil). They can be involved in the food chain and have toxic effects.
Pesticides, because of their intensive use in agriculture, make the soil heavily polluted. Pesticides are very resistant (persistent) and remain in the soil for a long time. Their presence in the soil adversely affects the flora and fauna of the soil, decreases soil fertility and leads to groundwater pollution.
Nitrates and phosphates, ie nitrogen (N) and phosphorus (P) are essential elements for plant growth, but their overuse in agriculture leads to soil pollution. Increased concentration in soil leads to pollution of groundwater and surface water. If phosphorus is used in large quantities, it may also be in the soil in an amount that is toxic to the plants. For example, in Serbia, 60-70% of the soil is poor in phosphorus. By increasing the phosphorus content, which should have about 20-30 mg in the soil, maximum yields are achieved. In Serbia we have over 2 million hectares where the phosphorus content is in the range of 2 or 5mg.
Radioactive contamination by origin and source of radiation can be natural and artificial. Most of the total radiation absorbed by man comes from natural sources such as cosmic radiation, terrestrial or /излишно(unnecessarily) radiation, and radiation from radioactive sources found in the tissues of living beings. Terrestrial radiation originates from natural radioactive elements found in soil, especially in clay substrates and rocks, and is different in different parts of the Earth, and is especially large above uranium ore deposits. These days, much is being said and written about the increase in radioactive radium, which goes into the soil by fertilizing with artificial fertilizers, especially phosphorus. Natural phosphorites imported by mineral fertilizer factories contain radioactive radium. Radioactive substances can accumulate in water, soil, sediments or air, but concentrations are generally higher in aquatic than in terrestrial ecosystems, since the flow is faster in water than in soil. On the other hand, widespread use of radioactivity, the use of nuclear energy, and more and more often incidental situations in recent times, alarmingly indicate serious environmental consequences for the environment and, consequently, a significant impact on the environment soil.
2.3 Examples of cause and effect analysis techniques applied in agriculture
The basic indicators of soil fertility are: total nitrogen, easily available phosphorus and potassium, humus and calcium carbonate content, pH in water and potassium chloride, all determined on the basis of soil analyzes. These fertility indicators are subject to change during the period of soil exploitation in the agricultural production process. Therefore, monitoring them is of great importance for proper soil management. Fertility checks must be carried out every four years.
In this fertility control process, the most responsible segment is certainly the soil sampling process. The soil sampling process consists of several stages: determination of sampling time, preparation for sampling, sampling, preparation and packaging of the soil sample.
The best time to collect samples from the soil is after the crop is harvested. The soil is flat at that moment, with undisturbed structures, and movement on such plots is significantly facilitated. Soil sampling can also be carried out during vegetation, and the most common cause are the deficiencies of certain nutrients on cultivated plants.
In the process of soil sampling, the goal is to form an average sample according to certain regulations and rules. The average soil sample is taken from a maximum area of 5 to 10 hectares depending on the homogeneity of the parcel.
The average soil sample from this area consists of 20 to 25 individual stitches and as many GPS coordinates. By returning to the parcel again, after 4-5 years, it is desirable to take soil samples from the same positions in order to detect a possible change in soil fertility.
After the sampling process is done, the soil must be well ground, mixed and placed in polythene or canvas bags and sent along with the label with all necessary information to an accredited laboratory for analysis.
In this way, preconditions are acquired for obtaining adequate results of soil analyzes. It is then possible to determine precisely the quantities of mineral fertilizers to be applied and to determine the fertility potential of each parcel.
Zajecar district
According to the land analysis data that the Center for Agricultural and Technological Research in Zajecar started to work from 1986 to 2010, it made more than 10,000 analyzes, as did the PSC Negotin (1990 to the present), in the whole territory of Eastern Serbia there is total change in soil fertility[1]. Constant decrease of humus, limestone and basic macro and micro elements as well as high acidification of soil is evident.
These changes are clearly seen in the following example. Land sampling was done at 11 sites, on parcels owned by the PD Zajecar (Example 1). As the majority of macro and microelements are adopted in the pH range 6 - 7, the results show that out of 11 samples, only 2 cases (samples 4 and 6), soil provides satisfactory conditions for growth and development of cultivated plants and positive plant response to supplementary care measures (nutrition and nutrition of plants with mineral and organic fertilizers).
Based on the results of chemical soil analysis, soil repair measures were carried out in the 2016/2017 season, and before the wheat and sunflower crops were planted. Soil repair was done by introducing 1,000 kg / ha of inorganic soil tiller "pH PLUS" (35% CaO + 13,5% MgO + 0,2% B) and 1,000 kg / ha of organic pelleted fertilizer "BioFert" (NPK 4: 3: 3). The analysis of land in the same locations, which was done during September (tables in Example 2), and after the removal of crops showed that the repair measures in the first year gave a certain shift and that the measures must be carried out regularly from 3 to 5 years.
Example 1.
Results of the chemical analysis of the soil done by PD “Zajecar” at 11 locations in 2016 before performing the repairing measures
Basic chemical properties of soil
Lab. No | pH | CaCO3 | Humus % |
Total N % |
AL-P2O5 mg/100g |
AL-K2O |
|
in KCI | in H2O | ||||||
1 | 3,79 | 5,17 | 0,00 | 2,07 | 0,154 | 7,8 | 25,5 |
2 | 4,17 | 5,59 | 0,00 | 2,33 | 0,173 | 5,7 | 24,1 |
3 | 4,10 | 5,47 | 0,00 | 2,56 | 0,190 | 4,4 | 22,7 |
4 | 4,63 | 6,15 | 0,00 | 1,71 | 0,147 | 7,9 | 16,4 |
5 | 4,43 | 5,77 | 0,00 | 2,36 | 0,176 | 8,1 | 30,9 |
6 | 5,47 | 7,03 | 0,00 | 1,73 | 0,149 | 3,1 | 15,0 |
7 | 4,40 | 5,85 | 0,00 | 1,74 | 0,150 | 5,2 | 29,5 |
8 | 4,04 | 5,32 | 0,00 | 1,59 | 0,137 | 9,4 | 20,0 |
9 | 3,80 | 5,10 | 0,00 | 1,80 | 0,155 | 6,0 | 20,0 |
10 | 4,59 | 5,98 | 0,00 | 1,90 | 0,164 | 4,0 | 20,5 |
11 | 4,60 | 5,99 | 0,00 | 2,64 | 0,196 | 3,1 | 26,8 |
Content of Microelements (in EDTA)
Lab. No | Cu mg/kg |
Zn mg/kg |
Fe mg/kg |
Mn mg/kg |
1 | 19,3 | 1,2 | 195,9 | 128,2 |
2 | 21,8 | 1,1 | 157,7 | 134,1 |
3 | 19,6 | 2,7 | 180,6 | 136,9 |
4 | 18,5 | 1,5 | 111,6 | 80,9 |
5 | 22,2 | 2,3 | 193,7 | 137,5 |
6 | 16,0 | 5,0 | 119,8 | 195,2 |
7 | 20,3 | 1,9 | 166,7 | 191,7 |
8 | 13,9 | 10,0 | 114,1 | 123,8 |
9 | 15,2 | 0,8 | 212,5 | 158,7 |
10 | 17,9 | 0,6 | 146,9 | 239,2 |
11 | 6,3 | 0,8 | 141,2 | 226,5 |
Boron content (in hot water)
Lab. No | B mg/kg |
1 | nd |
2 | 0,088 |
3 | 0,157 |
4 | 0,028 |
5 | 0,108 |
6 | nd |
7 | nd |
8 | nd |
9 | nd |
10 | 0,050 |
11 | 0,065 |
Results of chemical analysis of soil after repair measures have been performed (BioFert 4:3.3 1.000 kg/ha + pH Plus 1.000 kg/ha) during winter and spring 2017
Basic chemical properties of soil
Lab. No | pH | CaCO3 | Humus % |
Total N % |
AL-P2O5 |
AL-K2O |
|
in KCI | in H2O | ||||||
1 | 4,14 | 5,65 | 0,00 | 1,55 | 0,133 | 2,4 | 18,2 |
2 | 3,91 | 5,40 | 0,00 | 1,49 | 0,128 | 7,0 | 20,0 |
3 | 3,92 | 5,41 | 0,00 | 1,77 | 0,152 | 10,0 | 33,2 |
4 | 4,12 | 5,59 | 0,00 | 1,50 | 0,129 | 3,2 | 18,2 |
5 | 4,49 | 5,62 | 0,00 | 2,39 | 0,178 | 12,8 | 38,2 |
6 | 4,16 | 5,33 | 0,00 | 2,09 | 0,155 | 10,8 | 35,0 |
7 | 4,28 | 5,43 | 0,00 | 3,06 | 0,210 | 12,8 | 44,0 |
8 | 4,17 | 5,38 | 0,00 | 2,04 | 0,152 | 14,9 | 30,0 |
9 | 4,77 | 6,17 | 0,00 | 2,12 | 0,158 | 3,3 | 19,5 |
10 | 4,32 | 5,58 | 0,00 | 1,93 | 0,166 | 3,9 | 21,4 |
11 | 5,88 | 6,82 | 0,00 | 2,03 | 0,151 | 15,2 | 34,1 |
Content of Microelements (in EDTA)
Lab. No | Cu mg/kg |
Zn mg/kg |
Fe mg/kg |
Mn mg/kg |
1 | 20,18 | 2,01 | 201,3 | 100,8 |
2 | 20,67 | 3,42 | 217,3 | 129,7 |
3 | 23,19 | 1,97 | 456,9 | 173,0 |
4 | 21,69 | 5,32 | 185,5 | 118,2 |
5 | 25,48 | 2,28 | 390,5 | 200,6 |
6 | 26,56 | 3,62 | 266,3 | 183,2 |
7 | 31,78 | 13,50 | 249,9 | 210,7 |
8 | 22,15 | 4,10 | 202,8 | 136,8 |
9 | 25,69 | 4,04 | 179,1 | 211,1 |
10 | 26,04 | 1,67 | 208,8 | 247,4 |
11 | 12,38 | 2,04 | 163,5 | 207,8 |
Boron content (in hot water)
Lab. No | B mg/kg |
1 | 0,5099 |
2 | 0,4281 |
3 | 0,5056 |
4 | 0,3563 |
5 | 0,5587 |
6 | 0,3821 |
7 | 0,5795 |
8 | 0,2911 |
9 | 0,3513 |
10 | 0,3374 |
11 | 0,4368 |
Vidin district
The problem is the valley along the Timok River due to pollution originating from the RTB Bor mine (Serbia), which led to chemical degradation of the soil in Bulgaria as well. The average copper content is particularly high in the area of Rakitnica and Bregovo villages (300-500 mg / kg), and the most polluted are the chernozem in these areas. Another area in this region with heavily contaminated soils is the Balei-Kudelin area, where the most polluted are the alluvial - carbonate soils. Some lead contamination is also present on the entrance highway of the city of Vidin. In total, there are about 800 hectares of contaminants, mostly heavy metals, in the area, of which about 600 hectares are copper contaminants.[1]
[1] Atanassova Irena, Zgorelec Zeljka, Simeonova Tsetska, Simeomova Cecka, Velichkova Nikolaya, Atanassova Dimitrova Irena (2018): Solubility and availability of copper, zinc lead and iron in technosols under the effect of increasing copper levels. International Journal of Hydrology, Volume 2 Issue 3.
[1] City of Zajecar (2012): Environmental program on the territory of the city of Zajecar for the period from 2012 to 2019, Zaječar
2.4 Applied analysis techniques for risk assessment and prevention of soil pollution
Only the analysis of soil fertility gives a true indication of whether there has been a disturbance of the physicochemical characteristics of the soil, disturbance of the pH value, humus content, excess or lack of an element. Deficiency is a problem, but excess is also dangerous. This problem has been noticed since the period when larger quantities of mineral fertilizers began to be applied, and less organic fertilizers. Soil acidity is characterized by having an impaired balance of cations, primarily calcium and magnesium in the soil, which leads to increased absorption (uptake) of aluminum. The accumulation of aluminum in the soil results in the plants adopting it, which causes rapid decay of the plants as it is extremely toxic. For example, according to the latest data of 3.5 million hectares of arable land in Serbia, almost 1.5 million hectares have risky, acidic land.[1]
Changes in humus content, as well as soil pH, have been occurring and are intensified since the beginning of intensive use of mineral fertilizers. As the humus began to break down microbiologically, the addition of the nutrients needed by the microorganisms began. Also, where the harvesting residues were plowed, as good agricultural practices suggest, there was no significant decrease in humus. Organic matter does not disappear immediately, but gradually. In countries like the Netherlands where there is a lot of livestock and manure, organic matter is completely preserved. Unfortunately, livestock stock is constantly decreasing in the territory of Serbia, which greatly influences the deposition of organic matter (manure) in agricultural land.According to experts, the level of humus in soil in Serbia is already below 3%, which is at the limit of optimum and certainly not a great result. Organic matter, before the beginning of intensive agriculture in the fields of Vojvodina in the second half of the 20th century, was more than 5%, and in the last twenty years it has decreased from 3.5% to 3%.[2]
[1] https://poljoprivreda.info. Agricultural soil is constantly reducing
[2] Dnevnik (2018): No manure in the Serbian field will lead to infertile soil - Urgent increase in livestock needed, Novi Sad
2.5 The most common pollution factors in the cross-border area of Zajecar and Vidin
Zajecar district
RTB Bor. Copper production in Bor since 1903 has been an important source of environmental pollution. Dust, waste water and air pollutants affect the quality of soil, water and air. By the permanent spillage of pyrite tailings from the RTB Bor flotation tailings into the Bor River and from the Bor River at the point of its flow (Vrzogrnac) to Timok, the fertile agricultural land in the Timok Valley was destroyed. This process of soil pollution, but also of watercourses and groundwater in an area of over 2,000 hectares began in the 1950s with a drastic increase in the exploitation of copper ore and its further processing. The depth of the pyrite layer, which had been accumulating in the coastal area of Bor River and Timok for years, ranged from a tens of centimeters to one meter deep. Along with direct damages, indirect damages were also caused by the depletion of desiccated pyrite under the influence of wind on non-pyrite surfaces, which caused crop damage and environmental pollution over a large area. In the 1970s, a flotation tailings pond was built at RTB Bor and the further application of pyrite to the already destroyed land ceased, but the damage remained irreparable until today.
Chemical Industry Prahovo. IHP Prahovo was founded in 1960 as a factory of superphosphates, that is, as a chemical part of the metallurgical complex of the Bor Basin. Since then, IHP has expanded its capacity and product range. The first stage was the Superphosphate Factory (SF / PAF), then the Phosphoric Acid Factory 1 and 2, the Complex Fertilizer Factory (NKP), then the Sodium Tripolyphosphate Factory, the Cryolite Factory, the Monoammonium Phosphate Factory (MPF), the Aluminum Factory triluoride, phosphoric acid concentration and finally sulfuric acid factories. The soil is polluted by sedimentation of pollutants that are emitted into the air from the technological process, but much more by the spreading of the pyrite burn from the Prahovo soilfill as well as by the seepage of atmospheric water from the phosphogypsum landfill. Besides soils under landfills, the surrounding area is polluted as a result of the wind rose, primarily agricultural soil of the surrounding cadastral municipalities of Prahovo and Radujevac, and sometimes the pollution has a transboundary character as it is transferred by wind to the neighboring border area of Romania and Bulgaria. Previous studies have shown that most samples exceed the maximum allowable values for nickel, copper, arsenic and cadmium content.
Other soil pollutants. Local soil pollution is mostly prevalent in industrial zones where activities were carried out that could easily contaminate the soil.
The exploitation of mineral resources, which is intensive in the area of Zaječar, especially on surface mines, leads to complete degradation of the soil, not only at the site of exploitation, but in a much wider area around the exploitation field, including transport routes to the final destination of mineral resources. Such is the case with the coal mines "Vrška Čuka" Prlita (Zajecar), „Lubnica "(Zajecar)," Soko" Citluk (Sokobanja), the quarries "Rgotski Karst" near Rgotina and "Čokonjar"(Zajecar), as well as the exploitation of quartz sand in the area of Rgotina.
The eighties and nineties of the last century were marked by the Crystal Factory "Crystal“ Zaječar. It emitted a significant amount of harmful elements into the atmosphere (arsenic, mercury, cadmium ...) in certain zones of the then municipality of Zajecar, but also in other municipalities of our conutry, as well as in neighboring countries.
Inadequate waste disposal is certainly one of the main polluters of the soil. Much of the soil pollution comes from the wild landfills near towns and villages. Soil pollution is present in every rural settlement, especially in compacted settlements, due to unregulated wastewater from septic and manure pits.
Livestock farms were becoming major soil pollutants in the last two or three decades, primarily because of inadequate and uncontrolled disposal of solid and liquid waste on agricultural soil. Along with many so called home farms (20-50 cattles), in the district of Zajecar, there are two big capacity farms (over 2000 cattles), a „Halovo“ (Zajecar) pig fattening farm and an „Alapin“ (Zajecar) sheep fattening farm.
Vidin district
In 2017, a study was conducted using state-of-the-art monitoring networks to assess the physicochemical status of soil in the Vidin region and suggest optimal soil use practices. In the observed territory, the predominant soils are carbonate chernozem. Soil pH values are from neutral to slightly alkaline. Due to the rinsing process, the pH in the surface horizon is slightly acidic to neutral (6.0 - 6.6).
Environmental protection against pollution and damage (atmospheric air, water, soil, underground, soilscape, natural sites, mineral diversity, biodiversity and its elements) in the Vidin Region is performed by the Regional Inspectorate of Environment and Water - Montana (RIEV - Montana), which is a regional body of the Ministry of Environment and Water of the Republic of Bulgaria. Based on the results of the last analysis conducted between September 1 and October 15, 2018, no heavy metals were detected above the LC (lethal - lethal concentration).
The contamination is monitored in three groups of organic compounds: polycyclic aromatic hydrocarbons (PAH16), polychlorinated biphenyls (PCB6) and organochlorine pesticides. Testing shows that the content of persistent organic pollutants is below the maximum permissible concentrations (MPC). One of the main persistent organic pollutants is organochlorine pesticides, which were widely used in agriculture in the 1960s. Under the Bulgarian-Swiss Cooperation Program, the project "Environmentally friendly disposal of unusable pesticides and other plant protection products" has been approved and is being implemented in 2019. Analysis of the available information shows that no PAH and PCB contaminated soil has been registered at this stage.
Erosion is defined as the most serious threat to soil degradation in Bulgaria. Much of the territory controlled by RIEV-Montana has a slope above 18-20%, which is a basic prerequisite for the development of erosion. However, there are no major problems with soil erosion in the observed area.
The soils under RIEV-Montana controll are in good ecological condition with respect to biogenic reserves / organic matter, heavy metal and metalloid content as well as persistent organic pollutants.
2.6 Agricultural production as a cause of soil pollution
Agricultural production is one of the oldest human activities. Man's constant need for food thousands of years ago led him to collect berries, seeds and green leaves, which is considered one of the primitive connections and forms of agriculture. With the development of civilizations in Mesopotamia, Egypt, India and China soil cultivation methods were also developed, all the way to the so-called the first "agrarian revolution" in the 18th century that led to radical changes. They began to cultivate the soil mechanically and feed more and more people. Today, modern agriculture is responding to more and more demanding requirements, both in food production and environmental protection, despite tremendous technological and manufacturing advances.
In the first half of the twentieth century, man introduced the use of pesticides, mineral fertilizers and high-yielding plant genotypes into agriculture, and starterd using heavy machinery to cultivate soil. The famine has decreased, but humanity has faced a serious environmental crisis. In addition to fossil fuel production, intensive agriculture is considered one of the most aggressive human impacts on nature.
The negative effects of intensive agricultural production on the environment are particularly evident in rural areas, since most of their territory is used for food production. According to a 1991 study by the United Nations, different soil management practices have led to the degradation of 38% of arable soil, and the cause-and-effect relationship between intensive agriculture and soil erosion was evident. The consequences of overexploitation of soil were manifested as early as the early 20th century, when eolian erosion occurred on large areas in the southern United States, after decades of intensive cultivation, and thousands of families had to leave flee.
It should be said that the focus of agricultural production towards the end of XX and the beginning of this century is moving towards the principles of organic agriculture, the protection of fertile soil, water and air, reducing the impact on climate change and adapting to these changes.
Due to the intensive agricultural production, arable soil is converted into desert at the rate of 2300 square kilometers per year. If temperatures increase, the processes of decomposition of organic matter are accelerated, especially on intensively cultivated soils, leading to rapid degradation, declining productive potential and structural collapse of the soil. As a result of excessive irrigation, the water mobilizes the salt deposits and brings them into the surface layers and creates a salty soil. As most plants do not tolerate high concentrations of salt, such soil becomes unusable for agricultural production. It is estimated that the global losses caused by salinisation of agricultural soil amount to about 20% of the total irrigated area, or about forty-five million hectares of soil.
In agriculture, the most common pollutants are agrochemicals: pesticides, fertilizers and salts. Agricultural production uses fossil fuels to produce fertilizers and pesticides, for example, in the UK and the US, they account for about 2.4% of their total consumption. At the beginning of the twenty-first century, the annual value of pesticides on the world market was twenty-five billion dollars, about three billion of which were generated from sales in developing countries.
All this clearly shows that increasing agricultural productivity has a significant impact on environmental pollution. Only 10-15% of the applied pesticides reach the target pests, and the rest ends up in air, water and soil.
The most common pollutants, pesticides, have a long history. Historically, fungicides developed first, then insecticides, and last herbicides. Specifically, in 1755, arsenic and mercury sublimates were recommended and used for the treatment of wheat seeds, and copperarsulfate from 1761. Since 1824, the use of sulfur has been recommended and since then so-called "sulfur era," and in the mid-nineteenth century sulfur-lime broth was used to prevent grape moldiness. Copper and its compounds were finally recognised in the nineties of the nineteenth century (1885) through the action of a mixture of copper sulphate and lime so-called bordeaux mixture, in the suppressing of the causative agents of grapevine. This year is also being taken as the beginning of industrial production of pesticides and entering the "copper era". The so-called era Organic, synthetic fungicides began in the 1940s and last till today.
As for insecticides, a group of organochlorine non-systemic insecticides were developed in the 1930s, and among the first is hexachlorocyclohexane, better known as lindane (1942), and then aldrin, endrin, dieldrin and endosulfan are developed. Due to its toxicological characteristics, most of the insecticides from this group have been withdrawn entirely or partially from application, by the so-called Stockholm Convention of 2001, the insecticides aldrin, chlordane, dieldrin, endrin, heptachloride of this group, as well as DDT, mirex and toxafen from other groups, were put on the list of permanent organic pollutants whose production and use were prohibited. In the later period organo-phosphates, pyrethroids, neonicotinoids were created...
The first informations on the effects of some primarily inorganic compounds that destroy plants occurs at the end of the 19th century. Ferrosulfate, copper sulfate, sodium nitrate, sodium chlorate are used. The advancement of science encourages extensive research, so in the 1930s, chemical compounds that regulate the growth of plants, especially weeds, were tested. In the United Kingdom and the United States, 2,4D was discovered in 1942, one of the most widely used herbicides to date. Over the next fifty years, the production of herbicides has been increased twenty times or more, so in 1973, herbicides accounted for about 39% of the world's total pesticide production. One of the most significant, well-known and well-used groups of herbicides are the so-called soil herbicides from the Triazina group (amitrol 1954, simazin 1956, prometrin 1957, atrazine 1958 and terbutilazine 1966). As a consequence of the adverse effects on the living world, both in water and in the soil, at the end of the first decade of this century, most of these herbicides were banned from using. In the last two decades, sulfonyl urea groups and phenoxy groups are developed, etc.
Pesticides introduced into the soil may, depending on the dose and type of preparation used, alter the composition of the soil microflora. Soil fungicides and fumigants, usually, have a negative effect on soil microflora. A general indicator of the effect of pesticides on microflora is the biological activity of the soil or the intensity of the soil respiration (O2 sorption, CO2 release). Herbicides decompose relatively quickly in soil and their application at recommended doses does not adversely affect soil microflora. When introduced into the soil in increased doses, a temporary regrouping of the microflora composition occurs. The nature and extent of the action on the fauna are conditioned by the properties of the preparation, their content in the soil, the composition of the fauna and the soil and climatic conditions.
At the same time, scientific research indicates that intensive agriculture has led to a very simplified structure of agroecosystems around the world, so that today, in all climatic zones, a total of 12 types of cereals, 23 types of vegetables and 35 types of fruits are grown. A total of 70 species on about one thousand four hundred and forty million hectares of arable soil in the world is a great contrast to the diversity in tropical rain forests, where one hectare can have a hundred species of only woody plants.
The agricultural dominance of five crops - wheat (200 million hectares), maize (140 million hectares), soybeans (100 million hectares), rice (92 million hectares) and barley (55) - also indicates that agricultural systems are designated as significant pollutants to the ecosystem, which is also considered to be a consequence of intensive agriculture. Today, these five crops occupy 38% of the total arable land. These monocultures have replaced the natural ecosystems that used to be the habitat for hundreds, even thousands of species of plants, insects, and many species of vertebrates. The disappearance of forests, which is most often caused by their deforestation and conversion to agricultural soil and the accumulation of greenhouse gases, especially carbon dioxide, are irreversible processes and the consequences will be felt for a period of hundreds of years.
2.7 Agricultural soil pollution in Europe
The environment of European countries faces serious global challenges that include a growing population both in EU countries and EU candidate countries, followed by a rise in the middle class with high consumption rates, rapid economic growth in developing economies, an ever-increasing need for energy and an increased global competing for resources. European Union countries have significant sources of information and technology, new methods of resource management, a well-established culture of precaution and prevention, a history of repairing damage at the source itself and ways to get polluters to pay. Environmental management can be made more efficient through greater commitment to environmental monitoring and up-to-date reporting of pollutants and waste, using the best available information and technologies.
Although certain agricultural technologies have significantly contributed to increasing the productivity of agricultural production, such as the use of pesticides and mineral fertilizers, they now threaten environmental sustainability of agriculture.
Damage estimates from soil degradation in Europe vary, with damages only from soil erosion going from € 0.7 to € 14 billion per year and from the loss of soil organic matter between € 3.4 and € 5.6 billion per year.[1] A total amount of estimated damage for 28 EU Member States from soil degradation is around € 38 billion per year. However, there are also positive cases as well, so in Romania they have so-called "fresh soils", soils that are not very fertilized, where the humus content has remained at about 5-7% even today.
Soil degradation in the EU involves several aspects, the most important being: erosion, soil organic matter reduction, soil compacting or hardening, salinization.
Water-affected soil erosion covers an area of about 112 million hectares, or 12% of Europe's total soil, and 42 million hectares of soil is affected by wind erosion - 2% of which is severe erosion. In total, about 1/6 of the total EU soil area is affected by erosion processes.
Soil organic matter plays a major role in the carbon cycle of soil. At the same time, the soil is a greenhouse gas emitter (affecting climate change, such as carbon dioxide and methane), and is also the largest warehouse containing about 1500 gigatons of organic and inorganic carbon. Approximately 45% of the soil in Europe has a very low organic matter content (meaning 0-2% organic carbon) and 45% of the soil has a medium carbon level (meaning 2-6% organic carbon). The problem is particularly noticed in the countries of southern Europe but also in parts of France, Britain, Germany and Sweden.
Estimates of the total soil area that faces a risk of compacting vary. Some authors consider that about 36% of European soil is subject to a high or very high degree of compacting. Other authors consider that 32% of the soil is highly exposed to this process, and 18% of the soil will be moderately affected by compacting.
Salinization is the process of accumulation of soluble salts in the soil, mainly of sodium, magnesium and calcium, to which about 3.8 million hectares of soil in Europe are exposed.
The first part of the study on the social sustainability of alternative food systems (organic food production, organic farming) in the Baltic Sea region, to which Germany, Poland, Lithuania, Latvia, Estonia, Finland, Sweden and Denmark come out, provides a clear warning of the poor state of the environment in the Baltic Sea basin as well as proposed measures to improve the situation.[2] The environmental situation in the Baltic Sea region is the result of specialization in agricultural production, industrial pollution, improper waste management and unsustainable ways of living that are prevalent in countries around the Baltic Sea. Decreased use of energy from non-renewable resources, as well as decreased use of other natural resources and elimination of pesticides, would reduce air, water and soil pollution. Increased recycling of nutrients within agricultural systems through the integration of crop and livestock production on the farm would reduce the outflow of harmful substances from the field.
The ever increasing environmental degradation is leading to more active role of governmental and non-governmental sector in EU countries. Also, the soil now, more than ever, faces the risk of irreversible damage caused by wind and laminar erosion, pollution, salinisation, depletion of soil organic matter and reduction of biological diversity. All this, as well as the views of a number of non-governmental organizations (Greenpeace, Catholic development agencies…), which criticized the agricultural policies of the developed countries so far and considered it unsustainable in many respects, lead to the European Parliament adopting a resolution in 2009 on the deterioration of agricultural soil in the European Union. The resolution assumes that agriculture is an economic sector that is highly dependent on natural phenomena but at the same time offers plenty of possibilities for intervention and the best means for preventing deterioration.
Along with the analysis of the current situation, measures have been proposed to improve the environmental situation:
- creating a well-designed strategy to sustain this activity,
- considering the role of European farmers in the fight against desertification, the key role of European producers is in the conservation of surface vegetation in areas affected by frequent drought and the particular benefits of permanent crops, meadows and forests in water harvesting,
- it is considered that the instructions and management methods of the Common Agricultural Policy (CAP) should clearly include the principles and instruments of climate protection (ie climate protection as well as mitigation of climate change) as well as reducing the damage caused by soil degradation,
- calling EU to implement information and training measures specifically targeting young farmers with the aim of promoting agricultural techniques that support soil conservation, especially in relation to the impact of climate change and the impact of agricultural production on the climate,
- calling the Council and the Commission to explore strategies for the restoration of damaged soil by using the incentive measures in order to limit the deterioration of the soil.
In response to the aforementioned requests, at the meeting of the Ministers of Agriculture of the industrialized countries, held in 2009, the so-called the G8 group, made up of the most industrialized and economically powerful countries in the world, the United States and Canada, Germany, the United Kingdom, France, Italy, Japan and Russia have committed to greater investment in sustainable agricultural production and rural development, with the aim of ensuring food security in the world.[3]
EU environment ministers adopted environmental development policies in June 2012, with aim of achieving an "ambitious vision for a green Europe 2050" in which economic growth will not disrupt the environment. However, they called for better enforcement of existing laws instead of passing new ones because the conclusions should provide guidance to the European Commission in preparing the next environmental strategy as the Sixth Environmental Action Program (EAP) expires[4]. Thereafter, European Commission in 2016[5] at the meeting of the G20 Agriculture Ministers, gives support to sustainable agriculture, and stresses its support for major global agreements, including the Sustainable Development Guidelines, the Paris Climate Agreement, and the WTO Nairobi agreement.
[1] Jones, A., Panagos, P., Barcelo, S., Bouraoui, F., Bosco, C., Dewitte, O., Gardi, C., Erhard, M., Hervas de Diego, F., Hiederer, R., Jeffery, S., Lükewille, A., Marmo, L., Montanarella, L., Olazabal, C., Petersen, J., Penizek, V., Strassburger, T., Toth, G., Van den Eeckhaut, M., Van Liedekerke, M., Verheijen, F., Viestova, E., Yigini, Y. (2012). The State of Soil in Europe. Publications Office of the European Union. JRC, Italy
[2] www.poljoprivreda.info (2010): Ekonomski efekti lokalizacije hrane (3)
[3] Karolić, R. (2015): Plowing land (I): Agricultural soil degradation in the European Union,www.agroekonomija.rs
[4] EurActiv.rs (2012): EU prepare new environmetal strategy
[5] www.akademijaart.hr (2016): G20 agriculture ministers are committed to sustainable agriculture and the fight against antibiotic resistance.