State the causes of soil pollution.

The causes soil pollution are deposition of solid waste, accumulation of non-biodegradable material and toxic chemicals etc., which come from the following sources:

1. Industrial waste — Industrial waste containing chemicals, when dumped in soil, cause soil pollution. For example, fly ash from thermal plants, chemicals from oil refineries pollute the soil.
2. Urban commercial and domestic waste — Non-biodegradable wastes like glass, plastic, polythene bags remain in the soil for a long time.
3. Chemical fertilizers — Chemical fertilizers when used, disturb the natural balance of the soil. They also contaminate water bodies through run-off.
4. Biomedical waste — Hospital wastes containing plastics, metal needles and chemicals are dumped in soil.
5. Pesticides — Pesticides show permanent accumulation in soil in the form of nitrates and phosphates.