SOIL POLLUTION

Sidra shakoor

SOIL POLLUTION

Definition:

• Soil pollution is the contamination of soil with harmful substances that can adversely affect the quality of the soil and the health of those living in it.

Causes:• failure due to corrosion of underground storage tanks• application of pesticides, • oil and fuel dumping, • leaching of wastes from landfills ,• direct discharge of industrial wastes to the soil.

• Health hazards:• Direct affect on human health.• Contamination of ground water aquifers.• Chronic exposure to chromium, lead and other metals,

petroleum, solvents, and many pesticide and herbicide can be carcinogenic, can cause congenital disorders.

• Remedies:• Phytoremediation• Incinerate• Household Chemical Disposal• Planting and Reforestation• crop rotation

AGROCHEMICALS

DEFINATION:

• Agrochemical,is a generic term for the various chemical products used in agriculture. In most cases, agrichemical refers to the broad range of pesticides, including insecticides, herbicides, and fungicides.

TYPES

• Rodenticides (for rodent control)• Insecticides (for insect control)• Fungicides (for fungus control)• Herbicides (for weed control)• Molluscicide (for Snails)• Nematicides (for nematode control)

ENVIRONMENTAL EFFECTS:

• While agrochemicals increase plant and animal crop production, they can also damage the environment.

• Excessive use of fertilizers has led to the contamination of groundwater .

• the runoff of fertilizers into streams, lakes, and other surface waters can increase the growth of algae, leading to the death of fish and other aquatic animals.

• Some older pesticides, like the powerful insecticide DDT (dichlorodiphenyltrichloroethane), remain active in the environment for many years.

• In North America, for example, it is believed that millions of wild birds are killed each year from exposure to the agricultural insecticide carbofuran.

PESTICIDES• DEFINATION:• A pesticide is any substance used to kill, repel, or control

certain forms of plant or animal life that are considered to be pests.

• CLASSES:• Broad spectrum pesticides (Diazinon, Trichlorfon)• Narrow spectrum pesticides• Systemic pesticides (Imidacloprid )

• RISK OF EXPOSURE TO PESTICIDES

• Farmers and their families and other persons who use chemical pesticides regularly are at greatest risk for achieving toxic levels in their bodies.

• Agricultural Health Study,

ADVANTAGES:

• Cost effectiveness• Flexibility• Protection of the environment• Quality, quantity and price of produce

Disadvantages:

• Residues in food• Entrance in the food chain• Ground water contamination• Resistance• 4000 and 19000 deaths each year, according to world health

organization statistics. • Chlorpyrifos cause severe birth defects as it is used widely as an

agricultural chemical.• They cause behavioral problems, hormonal disruptions,

neurological effects.

Insecticides

An insecticide is a pesticide used against insects. They include ovicides and

larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry

and the household.

TYPES OF INSECTICIDES

1) Organic +type Organochlorine (OC) – These insecticides are

produced by combining an organic molecule with chlorine. The most well-known insecticide of today, DDT, is classified as an organochlorine and works by attacking the nerve cells of insects

• Organophosphates (OP) – These types of insecticides are a

combination of an organic molecule and phosphates. They attack the insect’s nerve cells and are somewhat similar to the chemical agents of nerve warfare.

• Other types organic insecticides are Carbamates , Pyrethrum and Pyrethroids .

2) Inorganic types:Inorganic insecticides commonly contain

ingredients such as arsenic, lead, copper, and mercury

• Paris Green This product was utilized in the past

as an insecticide for protecting fruit against insect contamination. This chemical compound, containing copper and arsenate, is extremely toxic and used in fireworks as well as some paints.

• Silica Gel This product is found in certain

insecticide dusts and works to suffocate pests. It is more commonly used for ticks, termites and mites

Properties of perfect insecticide Properties of insecticides are as follows:-• High toxicity to target pest• Selective toxicity so beneficial insects are not

affected• No harmful residue• Cheap and safe to manufacture• Stabile under storage• Non corrosive• Residues readily and cheaply detectable

BENEFITS OF INSECTICIDES:Humans have attained important benefits

from many uses of insecticides, including:• increased yields of crops because of

protection from defoliation and diseases; • prevention of much spoilage of stored

foods; and • prevention of certain diseases, which

conserves health and has saved the lives of millions of people and domestic

animals

DISADVANTAGES:

Disadvantages of insecticides are as follows:-• recovery of treated populations

Pest populations quickly recover and bounce back, leading to repeated insecticide applications.

• Resistance. Large reproductive ability and short generation time help speed selection of resistant individuals and insecticides are than applied at ever increasing concentrations.

• Selective kill and environments alteration can lead to minor pests becoming major pests.

• Residues can be long lived and dangerous.

• Insecticides and their applications can be costly and time consuming.

DEFINITION OF FUNGI

• A pesticide used to kill fungi, especially those that cause disease.

• Streptomycin is a fungicide

• Two fungicides are copper sulfate pentahydrate (CuSO4) and Hexachlorobenzene (C6Cl6). Today more than 80% of fruit and vegetable crop acres in the U.S. are treated with fungicides every year.

TYPES OF FUNGI

• Mobility in a plant: remain on the surface of plants. Many contacts are potentially phototoxic (toxic to plants) and can damage the plant if absorbed.

• Role in protection: Repeated applications are needed to protect new growth of the plant and to replace material that has been washed off by rain or irrigation, or degraded by environmental factors such as sunlight.

• Breadth of activity: Single-site fungicides are active against only one point in one metabolic pathway in a pathogen .

• Mode of action. Fungicides kill fungi by damaging their cell membranes, inactivating critical enzymes or proteins.

• Type of chemical: inorganic or organic. Chemically, organic molecules are those that contain carbon atoms in their structure whereas inorganic molecules do not.

 Role of Fungicides in Disease Management

• In human medicines, most fungicides need to be applied before disease occurs or at the first appearance of symptoms to be effective.

• Fungicides can only protect new uninfected growth from disease. Also, few fungicides are effective against pathogens after they have infected a plant.

• . Fungicides can only protect new uninfected growth from disease. Also, few fungicides are effective against pathogens after they have infected a plant.

Why are Fungicides Needed

• To control a disease during the establishment and development of a crop.

• To increase productivity of a crop and to reduce blemishes.

• To improve the storage life and quality of harvested plants and produce.

Chemical fertilizer

• Soluble in water.• Contain only a small subset of the

minerals and nutrients .• Not support soil biology .• Produce from non renewable

resources.• Nutrient-deficiency of soil.• Maintained soils have high acidity.

Negative effect • Contamination of groundwater.• Effect on nervous system functions in

mice, as well as influence on children’s and fetus's developing neurological, endocrine and immune systems.

• Cause of acid rain.• The increase in the water-soluble nitrates

creates an influx of plant-life, which eats up oxygen and starves out fish

and crustaceans.

Effect on soil

• you apply chemical fertilizers for long period but oppositely beneficial insects will decline leading to the loss of pest control.

• long-term resistance the ecosystem has  of pesticide  which results in the lost of beneficial organisms, earthworm, micro-organism, and other species .

Positive effect 

• Phosphorus is the second most abundant nutrient in life.

• Nitrogen helps plants turn green by helping plants create chlorophyll.

• Iron protects roots and preventing the formation of phenol compounds.

• Plants use potassium to create sugars, starches and carbohydrates.

Reaction with Ammonia 

• Ammonium nitrate reacts with metal hydroxides, releasing ammonia and forming alkali metal nitrate:

          NH4NO3 + NaOH → NH3 + H2O + NaNO3

            NH4NO3 + KOH → NH3 + H2O + KNO3

IMPACTS Of SOIL POLLUTION, PESTICIDES & AGROCHEMICALS

ON ENVIRONMENT

IMPACTS ON SOIL POLLUTION

• Pesticides The pesticides used in agriculture have chemicals that last

long in the environment. In addition to killing the pests, they also effect some beneficial organisms like the earthworm in the soil. Organisms like earthworm are vital to the decomposition of materials and formation of soil.

• Acid Rains The acid rains can change the pH of the soil making it

unsuitable for cultivation.

• Garbage The household and other city garbage lies scattered in the

soil in the absence of a proper disposal system. Materials like polythene can block the passage of water into the soil and affect its water-holding capacity.

• Radioactive Substances Improper disposal of nuclear wastes can cause radioactive

substances to remain in the soil for a long time. These substances cause mutations.

• Night Soil Human excreta mixed with soil is called night soil. Open

latrines in the villages and some parts of cities are the source of this pollution. These contain disease-causing germs which can spread the disease. It is estimated that millions of children worldwide die before they reach the age of five due to lack of sanitary facilities.

IMPACTS OF PESTICIDES

• PESTICIDE POISONING: About one million pesticide poisonings occur globally every

year, resulting in 20,000 fatalities. About one-half of the human poisonings occur in poorer, less-developed countries, even though these places account for only 20% of the world's use of pesticides.

• CONTAMINATION: Pesticides can contaminate unintended land and water

when they are sprayed aerially or allowed to run off fields, or when they escape from production sites and storage tanks or are inappropriately discarded.

• EFFECT OF DDT: Environmental damage caused by pesticides have been

associated with the use of relatively persistent chemicals, such as DDT. Most modern usage of pesticides involves chemicals that are less persistent than DDT and related chlorinated hydrocarbons.

• EFFECT OF TOXICITY ON HUMANS: Pesticides causing extensive toxicity to humans. The most

famous case occurred at Bhopal, India, in 1984, in the vicinity of a factory that was manufacturing an agricultural insecticide. In that case, there was an accidental release of about 45 tons (40 tonnes) of deadly methyl isocyanate vapor to the atmosphere. This agrochemical-related emission caused the deaths of about 3,000 people, and more than 20,000 others were seriously injured.

IMPACTS OF AGROCHEMICALS

• Extensive use of fertilizers: • Eutrophication: