DEGRADATION AND RESTORATION OF SOIL

Transcription

1 CHAPTER VI DEGRADATION AND RESTORATION OF SOIL 6.0 Introduction Soil is a natural body consisting of layers of primarily mineral constituents of variable thicknesses, which differ from the parent materials in their texture, structure, consistence, color, chemical, biological and other physical characteristics. Soil is composed of particles of broken rock that have been altered by chemical and mechanical processes that include weathering and erosion. Soil is altered from its parent rock due to interactions between the lithosphere, hydrosphere, atmosphere and the biosphere. It is a mixture of mineral and organic constituents that are in solid gaseous and aqueous states. The sustainable use of soil resources depends on three factors: soil characteristics, related to environmental (climate, hydrologic etc.) conditions and land use. These factors interact with the system, where the change in one factor causes alteration in the others. Therefore the sustainable use of soil resources is a dynamic issue. It is important to assess our soil resources as the prime object of sustainable human existence. This approach needs to be an integral part of land use planning and decision making at different levels, ranging from the local to national scales. To answer the challenge of soil resource degradation, there is an urgent need to develop a common, simple and transparent method. 6.1 Kerala Government policies for the pollution of Soil The development of an economy is must for the implementation of appropriate development projects in the areas of agriculture, forestry etc., A policy for soil is imperative for improving the living conditions of people. Periodic monitoring of soil fertility to maintain and improve its productivity. Some of the soil policies of Kerala 128

2 government are: Adoption of soil and water conservation methods in man-made forests to make the land use system ecologically sustainable; Strengthening of soil conservation programs for preventing soil degradation. Identifying and promoting substitutes for river sand Assessment and monitoring of soil and water (surface and ground water) quality throughout the State on a continuing basis] State wide and local campaigns to minimize soil and run-off losses by carrying out extensive works like contour trenching, contour bunding, terracing, construction of small water storages and protection of the vegetal cover in the catchments areas as a part of a watershed based planning process. Protection of land and water bodies through appropriate soil from erosion as well as water and soil for pollution and degradation; Conduct of pre-irrigation and post-irrigation soil survey and post-irrigation soil survey for monitoring the impact of irrigation on soil conditions; Enactment of laws for appropriate land uses to protect the soil from erosion as well as water and soil for pollution and degradation; Restoration and reclamation of degraded areas including weed-infested areas, mined areas, grazing land and salt affected soils. 6.2 Dimension of the problem of soil degradation 1. Solid waste management and Soil Degradation in Grasim Rayon s at Mavoor. The solid waste which was generated by the Grasim Rayon in Mavoor has not only generated pollution in the air and water, but also added the effluents into the soil. This was due to the severe mismanagement of the solid wastes of the industry. The solid 129

3 waste consisted of poisonous heavy metals which were not suitably disposed. They were stored freely in one of the sites exposed to air and water. The rain water used to carry these substances and added into the Chaliyar River. As a result of the free access of the solid waste into the water, the water had high concentrations of heavy metals like mercury Copper, Nickel and Chromium. These effluents were not only carried along with the river water in the entire stretch but also permanently deposited these metals into the soil thereby making it dangerous and difficult for reclamation. The effluents therefore have penetrated deep into the soils causing innumerable health problems not only for the present generations, but they will continue to give problems for many generations to come. The pollution Control Board could not take any effective steps against M/s. Grasim Industries, Pulp Division, which generated solid wastes containing heavy metals threatening health standards. The Rayon industry which produced the effluents utterly failed to contain discharge of pollutants within the admissible limits. The government proposed for a committee which studied the pollution problems connected with this Mavoor rayon industry. The Committee was informed about the results of the study which was conducted on health effects on environment. Their findings projected that the people of Chungapally panchayat and Mavoor where the Rayons factory is situated are in the grip of cancer since the Management failed to adopt suitable measure for the storage and disposal of hazardous wastes. The issue is still grave in spite of the long standing agitation by the local people. Therefore, the Committee recommends that the Government should examine this issue in detail and initiate action for ensuring strict adherence of provisions of Hazardous Wastes (Management and Handling) Rules, Two significant types of soil degradation have occurred: 1. Chemical pollution in the soil. 2. Heavy metallic deposition and degradation of soil. 130

4 These two types of pollution are different in their nature and effects. Their regional concentration also differs between each other. 2. Chemical pollution: Chemical pollution in the soils has occurred due to the inundation of the waters from Chaliyar River into the agricultural fields. Chemical pollution is the result of the chemical effluents which were released into the waters from the Industry. The risk and spread of the chemical pollution could be observed in the nearby agricultural paddy fields where the fields are inundated with huge water. Therefore the soil was sampled from the agricultural fields where their concentrations is very high and they are vulnerable to harmful pollutants present in the soils where food is grown, since it is a threat to the health and it will get into our food cycle and affect the health of the population. 3. Heavy metallic deposition: Heavy metals have occurred due to the mismanagement of the solid waste. The data pertaining to the heavy metals was collected from the department of Kerala pollution control board (KPCB). The soil examination was done at the vicinity of the river bed by the KPCB. 6.3 Materials and methods Primary survey was conducted at eleven places around the study area to collect soil samples from agricultural fields to estimate the chemical composition of the coil. These samples were tested at the Center for Water Resource Development and Management (CWRDM) soil lab. The secondary data of soil was collected from soil department of Malappuram and Calicut. The soil analyses were conducted for ph, Electrical conductivity, Magnesium, Potassium, Calcium, and Sodium. The composition of soil as existed prior to the starting of this industry was collected from soil department 131

5 of Malappuram and Kozhikode district. GIS was used to convert point data to spatial continuous data by spatial interpolation. 6.4 Heavy metals in Mavoor industrial area Heavy metals are extremely dangerous for the health of the people, plants, and agricultural crops. High concentration and consumption of these metals can even cause deaths. The following table shows the heavy metals present in the soil at the vicinity of the Chaliyar River and its associated impact of health is also shown for each of the different metals. Heavy metals Source: Internet Table 6.0: Heavy metals in Mavoor industrial area Observed in the soil sample test Recommended daily dose 6.5 Degradation and restoration of soil Over dose Copper (Cu) mg As little as 10 mg of copper can have a toxic effect Zinc (Zn) mg Doses larger than 25 mg may cause anaemia and copper deficiency Nickel (Ni) 5-17 < 1 mg Products containing nickel may cause skin rash in case of allergies Chromium (Cr) 6-26 ppm 120µg Doses larger than 200 µg are toxic and may cause concentration problems and faintings It is essential to restore the soil because degradation of soil is one of the greatest loss to the region and the country at large. Soil is the primary resource by which civilizations grow. But the restoration of soil does not take place quickly, and it is not possible to estimate or project the restoration of soil to happen within a short period of 10 to 20 years. The work of restoration can be completed only over a very long period of time, and also through specific geographical and management conditions. The degraded 132

6 soils consisting of concentrated effluents are able to stand a chance for restoration under the following conditions: 1. In soils under flooded condition the effluents decline gradually over seasons successively. 2. Cultivation of Rice straw and grain did not contain any Cr in contrast to other metals, even at very high level of metal addition. 3. The reversion of Cr(VI) to nonextractable form was more sharp in alluvial and black soils while the laterite soil continued to maintain the extractable Cr(VI) for a longer period of flooding indicating its potential toxicity. 6.6 Chemical pollution in Mavoor industrial area The following is the soil analysis conducted in the agricultural soil Table 6.1: Soil quality in the Study area place Thiruvambadi Station No. 1 Station No. 2 Exchangeable bases cmol/kg (depth 30 cm) Ca Na K Mg Ph Ec Elathoor Station No. 1 Station No. 2 Beypore Station No. 1 Station No Kakodi Station No. 1 Station No Chaliyar Station No Station No Station No Source: department of soil Malappuram and Calicut

7 6.7 Spatial and temporal aspects in chemical composition of soil in the study area 1. Calcium (Ca) Most of the soil analysis in Ca is concerned with diagnosis of solid and solid-saline problems. The common effects of the calcium content in the soil are increased due to industrialization and allied activities. Higher concentrations of calcium in soil will give rise to higher ph in soil. Spatial and temporal aspects of Calcium Sl.No Range Fig.6.0:Calcium content Table.6.2:Calcium content in deffrent period Area in Before Rayon production area in sq. Kms. Calcium Percentage of land (Before) 134 After the Closure of the industry Percentage of land (After) Total Source: department of soil Malappuram and Calicut

8 Thiruvambadi, Elathoor and Beypore are 0.1 cmol/kg and Kakodi and Chaliyar is 0.45cmol/kg and 2.3cmol/kg respectively. During the time of the the contamination of the calcium content on the core part of Mavoor industrial region is neutral. 2. Electrical Conductivity (Ec) The electrical conductivity of the soil water system rises according to the content of the solulable salt. Electrical conductivity supports the growth of crops, rangeland plants, and trees. In the Mavoor industrial region the content of electrical conductivity is moderate; it is mostly due to the effluents of the degraded materials directly discharged into the Chaliyar River. Spatial and temporal aspects of Electrical conductivity Fig.6.1: Electrical condectivity 135

9 Table.6.3:Electrical condectivity Electrical conductivity Sl.No Range Area in Before Percentage of After the Percentage of Rayon land (Before) Closure of land (After) production area the industry in sq. Kms Total Source: department of soil Malappuram and calicut Sands have low conductivity and clays have high conductivity, soil electrical conductivity correlates very strongly with particle size and soil texture. Soils prone to drought or excessive water will show variations in soil texture that can be delineated using soil electrical conductivity. Since water-holding capacity is intimately linked to crop yields, there is enormous potential to use soil electrical conductivity measurements to delineate areas with different yield potential. Soil electrical conductivity also can delineate differences in organic matter content and cation exchange capacity (also known as Celectrical conductivity). 3. Potassium (K) Potassium (K) is an essential nutrient for plant growth. Because large amounts are absorbed from the root zone in the production of most agronomic crops, it is classified as a macronutrient. When the supply from the soil is not adequate, K must be supplied in a fertilizer program. 136

10 Spatial and temporal aspects of Potassium Fig.6.2: Distribution of Potassium Table.6.4: Potassium content in different period Sl.No Area in Before Rayon production area in sq. Kms. Potassium Percentage of land (Before) After the Closure of the industry Percentage land (After) Total Source: department of soil Malappuram and Calicut of After the closure of the industry the composition of local soil has undergone lot of changes. Although quick and dramatic changes are not possible within a short time, yet when man directly interferes definitely changes can happen fast and change the soil s ecosystem. The soils of the study area show a sudden transition. There are specific pockets in the study area which show extremely high levels of potassium. 137

11 4. Magnesium (Mg) Soil a non-renewable natural resource, has several functions in the biosphere and for humans. It is a reactor, transformer and integrator of material and energy from other natural resources. Spatial and temporal aspects of Magnesium Fig.6.3: Distribution of Magnesium Sl.No Range Table.6.5: Magneium content in different period Area in Before Rayon production area in sq. Kms. Magnesium Percentage of land (Before) After the Closure of the industry Percentage of land (After) Total Source: department of soil Malappuram and Calicut 138

12 5. Sodium (Na) Though out a plant food nutrient, sodium plays a critical role in soil and turf grass health. The primary problem posed by high sodium is not a toxicity hazard, but a rapid decline in soil structure that can begin when sodium base saturation exceeds the critical 5% level. High sodium reduces soil permeability, resulting in drainage and compaction. Sodium is essential for animals and herbivores depend on the content in plants to supply their needs. There is, therefore, a role for sodium in herbage species additional to that of plant nutrient. Sodium is highly susceptible to leaching and available soil sodium can be lost over winter. It is not possible to build up reserves of sodium in the soil by repeated applications over years. High levels of exchangeable sodium can disperse clay particles resulting in a loss of soil structure. High sodium in land can generally be treated with Gypsum or Lime. Spatial and temporal aspects of Sodium Fig.6.4: Distribution of Sodium 139

13 Table.6.6: Sodium content in different period Sodium Sl.No Range Area in Before Percentage of After the Percentage of Rayon production area in sq. Kms. land (Before) Closure of the land (After) industry Total Source: department of soil Malappuram and Calicut 6. Hydrogen potentials (ph) ph is a scale that chemists use to measure acidity. Values below 7 are considered acidic, values above 7 are alkaline (the opposite of acidic) and 7 is neutral. Apart from the other chemical content the hydrogen potential content in the Mavoor industrial region is equal in all part. During this period the only 5.1 is found in Beypore, Elathoor and Thiruvambadi region and 4.9 is found in the reaming part of Chaliyar and Kakodi regions. This study shows the hydrogen potentials in Mavoor rayon industrial region is neutral position in the all period of time since

14 Spatial and temporal aspects of Hydrogen potential Fig.6.5:Hytdrogen potential Table.6.:7 Hydrogen potential content in different period Hydrogen potential Sl.No Range Area in Before Rayon production area in sq. Kms Percentage of land (Before) After the Closure of the industry Percentage of land (After) Total Source: department of soil Malappuram and Calicut 141

15 Soil Quality before and after the closure of the rayon industry (a) (b) Fig: 6.6 Soil qualities before and after the establishment of Rayon Industry 6.8 Conclusion Investigations were carried out to characterize the polluted soils from rayon (Mavoor) industry through a series of laboratory experiments. The soil problems identified in four out of eleven locations studied in the rice growing area around were mainly due to high ph (8.5-9) associated with high alkalinity. However, no heavy metal accumulation could be attributed to the problem in agricultural fields. The liquid waste from rayon factory was alkaline containing high oxidisable organic carbon (14 mg/1 COml) and low in metal contaminants. 142