SUPERVISION Prof. Dr. Mervat Salah SOIL POLLUTION SUPERVISION Prof. Dr. Mervat Salah

What causes heavy metal pollution? Anthropogenic causes Heavy metal- released to the river/ocean from numerous sources. Typical sources- 1. municipal wastewater-treatment plants 2. manufacturing industries, 3. mining, 4. transportation 5. rural agricultural cultivation & fertilization. transported as either dissolved species in water/ integral part of suspended sediments. may be volatilized to the atmosphere or stored in riverbed sediments. Toxic heavy metal- taken up by organisms; the metals dissolved in water have the greatest potential of causing the most deleterious effects.

What is soil pollution? Another way of looking at it…. Soil is a resource Increasing use of agrochemicals (herbicides, pesticides), Green Revolution Soil pollution comprises the pollution of soils with materials, mostly chemicals, that are out of place or are present at concentrations higher than normal which may have adverse effects on humans or other organisms. It is difficult to define soil pollution exactly because different opinions exist on how to characterize a pollutant; while some consider the use of pesticides acceptable if their effect does not exceed the intended result, others do not consider any use of pesticides or even chemical fertilizers acceptable. However, soil pollution is also caused by means other than the direct addition of xenobiotic (man-made) chemicals such as agricultural runoff waters, industrial waste materials, acidic precipitates, and radioactive fallout. Both organic (those that contain carbon) and inorganic (those that don't) contaminants are important in soil. The most prominent chemical groups of organic contaminants are fuel hydrocarbons, polynuclear aromatic hydrocarbons ( PAHs ), polychlorinated biphenyls ( PCBs ), chlorinated aromatic compounds, detergents, and pesticides. Inorganic species include nitrates, phosphates, and heavy metals such as cadmium, chromium and lead; inorganic acids; and radionuclides (radioactive substances). Among the sources of these contaminants are agricultural runoffs, acidic precipitates, industrial waste materials, and radioactive fallout.

Metals have unique chemical properties 1. Do not decay like organics 2. Necessary and beneficial to plants 3. Always present at background levels from parent rock weathering 4. Often occur as cations, which are actively exchanged in plant cell processes In soil science, cation exchange capacity (CEC) is the capacity of a soil for ion exchange of cations between the soil and the soil solution. CEC is used as a measure of fertility, nutrient retention capacity, and the capacity to protect groundwater from cation contamination. Cations can also be easier to understand by just adding the group number. The quantity of positively charged ions (cations) that a clay mineral or similar material can accommodate on its negatively charged surface is expressed as milli-ion equivalent per 100 g, or more commonly as milliequivalent (meq) per 100 g or cmol/kg. Clays are aluminosilicates in which some of the aluminium and silicon ions have been replaced by elements with different valence, or charge. For example, aluminium (Al3+) may be replaced by iron (Fe2+) or magnesium (Mg2+), leading to a net negative charge. This charge attracts cations when the clay is immersed in an electrolyte such as salty water and causes an electrical double layer. The cation-exchange capacity is often expressed in terms of its contribution per unit pore volume, Qv.

Causes Of soil pollution Leakages from sanitary sewage. Acid rains, when fumes released from industries get mixed with rains. Fuel leakages from automobiles, that get washed away due to rain and Seep into the nearby soil. Unhealthy waste management techniques, which are characterized by release of sewage into the large dumping grounds and nearby streams or rivers.

Causes of Soil Pollution? . Industrial wastes, such as harmful gases and chemicals, agricultural pesticides , fertilizers and insecticides are the most important causes of soil pollution. Ignorance towards soil management and related systems. Unfavorable and harmful irrigation practices. Improper septic system and management and maintenance of the same.

Effects of Soil Pollution The effects of pollution on soil are quite alarming and can cause huge disturbances in the ecological balance and health of living creatures on earth. Decrease in soil fertility and therefore decrease in the soil yield. Loss of soil and natural nutrients present in it. Plants also would not thrive in such a soil, which would further result in soil erosion.

Effects of soil pollution Disturbance in the balance of flora and fauna residing in the soil. Increase in salinity of the soil, which therefore makes it unfit for vegetation, thus making it useless and barren. Generally crops cannot grow and flourish in a polluted soil. Yet if some crops manage to grow, then those would be poisonous enough to cause serious health problems in people consuming them.

Ignorance towards soil management and related systems. Soil pollution is a result of many activities and experiments done by mankind and some of the leading soil pollution causes are discussed below. Industrial wastes, such as harmful gases and chemicals, agricultural pesticides, fertilizers and insecticides are the most important causes of soil pollution. Ignorance towards soil management and related systems. Unfavorable and harmful irrigation practices. Improper septic system and management and maintenance of the same. Leakages from sanitary sewage. Acid rains, when fumes released from industries get mixed with rains.

Fuel leakages from automobiles, that get washed away due to rain and seep into the nearby soil. Unhealthy waste management techniques, which are characterized by release of sewage into the large dumping grounds and nearby streams or rivers. Creation of toxic dust leading is another potential effect of soil pollution. Foul smell due to industrial chemicals and gases might result in headaches, fatigue, nausea, etc. in many people. Soil pollutants would bring in alteration in the soil structure, which would lead to death of many essential organisms in it. This would also affect the larger predators and compel them to move to other places, once they lose their food supply.

Solutions for Soil Pollution Soil pollution has many sources, from agriculture to industry to human activity. Polluted soils affect harm life and, in turn, wildlife. Depending upon the polluting agent, pollutants can persist in the environment. Solutions, therefore, involve not just removing a source of pollution but also cleaning up and restoring the polluted area. Adding to the complexity of soil pollution is nonpoint source pollution (NSP), which enters the environment through runoff. Take any action at your disposal to reduce soil pollution, as you may not always find a clearly defined source.

Solutions for Soil Pollution Reduce Waste Consider the amount of needlessly generated waste . Chemicals used in paper manufacturing can end up in the soil -.Choose wisely when shopping; avoid purchasing products - With excessive packaging. Reuse holiday wrap, or cut down on the amount you use.

Solutions for Soil Pollution Agriculture Best Practices:- - Runoff contains pesticides, fertilizers, and agricultural waste that can have harmful effects on soils. - Excessive amounts of phosphates, phosphorus and nitrogen found in fertilizers can cause fish and plant kill, resulting in contaminated soils. - Use organic herbicides when gardening, or none at all. Plant native plants, which thrive in local conditions, often making pesticide use unnecessary

Solutions for Soil Pollution Reduction of Human Impact : - Finally, simply reduce your negative impact on the environment. . Recycle whenever possible to help ease soil pollution. Use cloth bags instead of paper or plastic at the grocery store, and substitute polycarbonate bottles for plastic water bottles. Reduction of Acid Rain Sulfur dioxide emissions can cause acid rain and forest destruction. Fortunately, the introduction of scrubbers on smokestacks of coal-burning power plants has produced some progress in this area.

Example Soil Pollution: The introduction of substances, biological organisms, or energy into the soil, resulting in a change of the soil quality, which is likely to affect the normal use of the soil or endangering public health and the living environment.

Soil contaminants are spilled onto the surface through many different activities. Most of these are the result of accidents involving the vehicles that are transporting waste material from site of origin to a disposal site. wearing level “B" protective gear wearing level “A" protective gear Much good agricultural land is threatened by chemical pollution, particularly - as here in China - by waste products from urban centres. Chemical degradation is responsible for 12 per cent of global soil degradation Source: UNEP, Zehng Zhong Su, China, Still Pictures Drilling to determine pollution extent wearing level “D" protective gear

Others involve accidents involving vehicles (automobiles, trucks and airplanes) not transporting wastes, but carrying materials, including fuel, that when spilled contaminate the soil.

Illegal dumping is the disposal of waste in authorized areas. It is also known as “open dumping”, “fly dumping”, and “mid-night dumping”.  Illegal dumps occur most often along isolated roadsides in remote areas of the country.  Materials often found in illegal dumps include large household ppliances, tires, excess building materials, old furniture, oil, household chemicals, and common household refuse. Washington state New York Iowa Missouri Virginia

Pollutant on soil surface Seattle, WA Pollutant on soil surface When any liquid pollutant is on or just below the ground surface for any period of time, one of three things could happen to it, if it is not cleaned up first. 1- pollutant might be washed away by precipitation, causing little or no harm to the ground on which it was found. pollutants will simply accumulate somewhere else) Waco, Tx

2- the pollutant, if volatile, could evaporate, again causing little harm to the soil (however, not a solution to the bigger pollution problem, as it might become a source of air pollution). 3- pollutant could infiltrate through the unsaturated soil, in much the same way as ground water.

Agricultural practices, including the use of agricultural chemicals, are another primary source of pollution on or near the ground surface. Most agricultural chemicals are water-soluble nitrates and phosphates that are applied to fields, lawns and gardens to stimulate the growth of crops, grass and flowers.

Agro Chemicals When not used by the plants the nutrients can enter streams and lakes during the run-off or leaching events. Once in a body of water, these nutrients continue to promote the growth of plants, the resulting plant detritus is food for micro-organisms, and as the population of such organisms grows, the supply of oxygen in the water is depleted.

Algae in streams Water is capable of supporting a large population of bacteria and the bacteria will have a high demand for oxygen. Soon the oxygen supply is depleted by the bacteria and other organisms in the water now lack oxygen (fish kills)

Soil Pollution Information needed to clean up materials added to soil include: 1) Kind of material - organic or inorganic - is the material biodegradable, is the material dangerous to animals and humans, 2) how much material was added to the soil, will it overload the organisms in the soil; 3) C:N ratio of the material, are additional nutrients needed ( N & P)

Soil Pollution 4) Kind of Soil - will the soil be able to handle the material before groundwater is contaminated, 5) Growing conditions for the soil organisms - is it too cold, too wet etc. 6) How long has the material been on the site - is there evidence of environmental problems, is it undergoing decomposition. 7) Immediate danger to people and the environment - Urgency of the situation.

Bioremediation A treatment process that uses microorganisms (yeast, fungi, or bacteria) to break down, or degrade, hazardous substances into less toxic or nontoxic substances (carbon dioxide and water)

Conditions that favor Bioremediation Temperature favorable for organisms Water available (near field capacity) Nutrients (N, P, K) in adequate supply C:N ratio of material < 30:1 Material added is similar to naturally occurring organic material Oxygen in sufficient quantity