A chemist shows a labelled flask in his hand; in the background other labelled flasks in an shelf.Click to enlarge
Toxicology is the study of poisons and incidences of poisoning.
Source: contrastwerkstatt /

Toxicology is the study of poisons and incidences of poisoning to which both artificial and natural substances can give rise in people. As a rule, a distinction is made between toxicology and eco-toxicology, the latter being defined as the effects of substances on organisms in populations and ecosystems.

What is toxicology?

Toxicological investigations on animals are known as in-vivo toxicology, whereas in-vitro or cellular toxicology gains its insights at a cellular level.

Risk assessment, damage prevention

Toxicology is an applied science, which investigates and describes the deleterious impacts on health of individual chemicals or substance compounds.  Effects are described according to the length of the investigations (e.g. short-term, chronic, life-long) and the kind of damage observed (e.g. irritative, caustic, mutagenic, carcinogenic, reproduction-toxic). Toxicologists do not only observe the effects which arise; they also try to clarify the chemical-biological interdependencies and, if at all possible, the actual mechanisms whereby the effects occur. The goals are to identify the hazards that arise from exposure to particular substances, to estimate the risks to human and animal health, and to find ways to prevent damage from occurring. For the purposes of risk assessment, information on the effects of longer-term exposure and irreversible effects is usually more significant than data concerning acute toxicity. This is of primary importance above all in respect of hazardous incidents and cases of poisoning.

The toxicity of substances and the intensity of their effects normally depends on the ingested dose. If scientists are to undertake a risk assessment they need, in addition to the toxicity profile, to take into account the strength of the effect, the principal characteristics of the injury caused, and the use of the substance. In some situations, ingestion of very small amounts of a highly toxic substance can give rise to a lower risk than a situation in which a less toxic substance are released in large amounts or in an uncontrolled way into the environment. In order to arrive at an estimation of the hazardous potential of substances and to be able to make precise as possible statements about potential risks, toxicology makes use of knowledge derived from biology, biochemistry, physiology, cellular biology, and pharmacology. All of this information is necessary to be able to define the toxicity of a substance as precisely as possible and to derive appropriate measures.

Establishing threshold tolerances and guideline values

The process of establishing tolerable threshold levels and guideline values is a fundamental but also especially difficult task for toxicologists. Effect-inducing mechanisms have to be analysed, and medical, biological, and physiological data collated and evaluated, all within a common framework.

One of the tasks of the German Federal Environment Agency (Umweltbundesamt) is to look for answers to questions concerning substances with various toxicological properties. Among our focal points are risk analysis for harmful substances in indoor air and for chemicals which are significant to the safety of chemical plants, as well as the evaluation of those harmful substances measured in the German Environmental Survey (GerES IV) for Children and the Environmental Specimen Bank, human specimen part. In addition, such particular aspects as the toxicology of endocrine disrupting chemicals and nano-particles are being investigated.