Agriculture, industry, urbanisation and nuclear activities generate large quantities of waste containing physical, chemical and biological contaminants. When these wastes are improperly handled, treated or disposed of, pollutants can enter the soil and disturb its physical, chemical and biological properties. Soil is an important component of the environment because it supports plant growth, stores nutrients and water, provides habitat for microorganisms and acts as a medium through which many substances move into groundwater and food chains. Therefore, contamination of soil by different categories of waste is an important environmental health concern. Agricultural waste contributes significantly to soil pollution, particularly where modern intensive farming practices are used. Agricultural activities generate crop residues, animal manure, pesticides, herbicides, chemical fertilisers, plastic materials and wastewater. Excessive application of chemical fertilisers is one of the major sources of soil contamination. Nitrogenous, phosphatic and potassium fertilisers are necessary for crop production, but their continuous and excessive use can alter soil chemistry. Excess nitrogen may be converted into nitrates, which can leach into groundwater, while excessive phosphate can accumulate in soil and subsequently reach nearby water bodies. Fertilisers may also contain trace amounts of heavy metals such as cadmium, lead and arsenic, which can accumulate in agricultural soils over time. Pesticides and herbicides are another important source of agricultural soil pollution. These chemicals are designed to kill insects, weeds, fungi and other pests, but some of them persist in soil for long periods. Repeated application can lead to accumulation of pesticide residues. Persistent organic pollutants may remain in the environment and can be absorbed by crops, entering the human and animal food chains. Some pesticides can also adversely affect beneficial soil organisms, earthworms and microorganisms that are essential for maintaining soil fertility. Agricultural plastics, including mulch films, pesticide containers, irrigation materials and packaging, can leave plastic fragments and microplastics in soil when they are improperly discarded or burned. Animal waste can also cause soil pollution when livestock manure, poultry litter and slaughterhouse wastes are disposed of without proper treatment. Such wastes contain organic matter, nutrients, pathogens, antibiotics and, in some cases, heavy metals. Excessive application of untreated manure may introduce disease-causing microorganisms and increase nutrient concentrations in soil. Agricultural wastewater containing salts, fertilisers, pesticides and organic matter can further degrade soil quality. Burning crop residues can deposit ash and pollutants on the land and may contribute to the accumulation of particulate matter and toxic compounds. Industrial activities are among the most serious sources of soil pollution because industrial waste may contain highly toxic and persistent substances. Industries such as mining, metal processing, electroplating, chemical manufacturing, petroleum refining, tanning, paper production, textile manufacturing and pharmaceutical production generate different forms of hazardous waste. If industrial effluents, sludge or solid waste are discharged directly onto land, pollutants can accumulate in the soil. Heavy metals are particularly important industrial soil pollutants. Lead, mercury, cadmium, chromium, arsenic, nickel and copper may be released from industrial processes. These substances are not easily degraded and can remain in soil for many years. Their accumulation may reduce soil fertility and harm plants