Residue of raw materials or waste separated out during the processing of crops or mineral ores.


A substance that causes defects in development between conception and birth. A teratogen is a substance that causes a structural or functional birth defect.

Tertiary wastewater treatment

Advanced cleaning of wastewater that goes beyond the secondary or biological stage to remove nutrients such as phosphorus and nitrogen and most biochemical oxygen demand (BOD) and suspended solids.

Thermal pollution.

Discharge of heated water from industrial processes that can affect the life processes of aquatic organisms.

Total Cropped Area

This represents the total area sown once and/or more than once in a particular year, i.e. the area is counted as many times as there are sowings in a year. This total area is known as gross cropped area.

Total Cultivable Area

This consists of net area sown, current fallows, fallow lands other than current fallows, culturable waste and land under miscellaneous tree crops.

Total Cultivated Area

This consists of net area sown and current fallows.

Total suspended solids (TSS)

A measure of the suspended solids in wastewater, effluent, or water bodies.

Total Un-Cultivable Area

It is the area arrived at by deducting the total cultivable area from the total reported area.

Total Un-Cultivated Area

It is the area arrived at by deducting the total cultivated area from the total reported area.


Poisonous or harmful to the body (ecotoxic relates to damage to the environment). 

Toxic agent

Chemical or physical (for example, radiation, heat, cold, microwaves) agents that, under certain circumstances of exposure, can cause harmful effects to living organisms.

Toxic pollutants

Materials contaminating the environment that cause death, disease, or birth defects in organisms that ingest or absorb them. The quantities and length of exposure necessary to cause these effects can vary widely.

Toxic substance

A chemical or mixture that may present an unreasonable risk of injury to health or the environment.


The degree of danger posed by a substance to animal or plant life.


The study of the harmful effects of substances on humans or animals.


A poisonous substance that can either be natural (produced by plants, animals or bacteria) or manufactured.

Trichloroethylene (TCE)

A stable, low-boiling point colorless liquid, toxic by inhalation. TCE is used as a solvent, as a metal degreasing agent and in other industrial applications.

Trickling filter

A coarse biological treatment system in which wastewater trickles over a bed of stones or other material covered with bacterial growth. The bacteria break down the organic waste in the sewage and produce clean water.

Tropical Cyclone

Storms of various intensities that form over warm tropical and subtropical waters; classified according to intensity and degree of organization and including tropical disturbances, tropical depressions, tropical storms, and hurricanes.

Tropical storm
A warm-core tropical cyclone in which the maximum sustained surface wind (1 minute mean) ranges from 34 to 63 knots (62.4-116 kilometers per hour).

A shallow water progressive wave, potentially catastrophic, caused by an underwater earthquake or volcano that can rise to great heights and catastrophically inundate shore lands.


An abnormal mass of tissue that results from excessive cell division that is uncontrolled and progressive. Tumors perform no useful body function. Tumors can be either benign (not cancer) or malignant (cancer). 


1. Haziness in air caused by the presence of particles and pollutants. 

2. A similar cloudy condition in water due to suspended silt or organic matter.