Human toxicity

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Toxicity generally describes the extent of the toxic effect of a toxic substance. The human toxicity (from Latin humanus 'human', also English human 'human', 'human'; from Greek τοξικότητα, from toxikón (phármakon) - arrow (poison) from toxa - bow and arrow) refers specifically to humans, i.e. . H. it is understood to mean the entirety of all substances that have a toxic effect on humans. It deals with numerous toxic substances such as heavy metals and organic substances that are directly harmful to humans. The effects can be very different: damage to the respiratory tract , the nervous system , the liver and kidneys , cancer , deformities , developmental disorders (trivalent arsenic , for example, is a well-known human toxic poison ).

Other names

Human toxicity according to CML (1991/92), human toxicological impacts according to SETAC Europe (1996), toxic hazard to humans according to DIN / NAGUS UA2 (1996), direct health damage according to UBA (1999).

Effects of substances toxic to humans

The substances and their effects are very different:

  • Cytotoxic effects (disturbance of cellular function, other than DNA changes or damage)
  • Respiratory damage,
  • Damage to the nervous system,
  • Damage to the liver and kidneys,
  • Chemical carcinogenesis,
  • Reproductive toxicity (embryo and foetotoxicity, teratogenicity [damage to the child] and effects on fertility [fertility]; all stages of reproduction can be affected),

Here, substances that are toxic to humans, as well as other substances considered toxic, are divided into three categories. The absorption of some substances is necessary for the organism. An overdose is toxic, but an undersupply of the body also has negative effects. Such substances are called essential substances. A distinction is also made between concentration and summation poisons. If the ingestion of a substance has reversibly toxic effects above a certain threshold value, and irreversibly sublethal and ultimately fatal effects at higher doses, this substance is referred to as a concentration poison. The dose-effect relationship typically shows a sigmoid (S-shaped curve: first flat, then abrupt, finally flattening rise again). If irreversible damage occurs regardless of the amount of substance absorbed, it is a summation poison. When ingested, the substance accumulates in the organism, e.g. B. by entering into covalent bonds. Effects of further gifts add up. Genotoxic substances are among the summation poisons.

Factors

Factors that influence the dangerousness of a substance are: concentration, exposure (time), absorption / kinetics, susceptibility and lifespan.

Concentration: Only when a certain concentration is exceeded does the substance have a toxic effect on an organism. There is no risk below this threshold value (“no-level effect”).

Exposure time: It states how long an individual is exposed to a substance. A shorter exposure time at high concentrations is often considered to be less dangerous than a long exposure time at a low concentration of the substance.

Absorption / kinetics: Depending on the substance, it can enter the organism through inhalation, oral ingestion or skin contact. The toxicity of one and the same substance can vary depending on the type of intake.

Vulnerability: Certain groups of people are potentially more at risk than others. The more vulnerable groups include a. Asthmatics, allergy sufferers, pregnant women, children, the elderly.

Lifespan: Depending on specific material properties, the presence of potential reaction partners, weather conditions, etc., some substances can be classified as toxic longer than others because, for example, they are viewed as highly toxic in the reactive state, but no longer pose a hazard in the bound of them.

Determination and measurands

The methods used under toxicity are used for determination and measurement .

Human toxicity as part of life cycle assessments

As an impact category, human toxicity can play a role in the impact assessment. According to the Federal Environment Agency, human toxicity is a category that is assigned to the life cycle inventory item group: Effects through chemical emissions. In this sense, it corresponds to an “output-related category”. In particular, the specific effects of biotechnology fall into the categories of human toxicity and ecotoxicity. These categories are close-range effects, even if the substances can be transported over long distances via the mobile media of air and water. One possible method for the quantitative assessment of the effects of human and ecotoxicity is the “Critical Surface Time” method (CST 95). When calculating the weighting factors, distribution and degradation behavior in the environment as well as toxicity data are included. The human toxicity potential (HTP) is given in lead equivalents. This methodology has proven particularly useful for assessing the impact of agricultural production methods.

See also

literature

  • W. Walk: Quantification of human toxic effects . Aachen 2002.
  • Human toxicity . EcoSMEs, ecosmes.net Status: September 16, 2004, accessed June 1, 2012.
  • I. Renner, W. Klöpffer: Investigation of the adaptation of life cycle assessments to specific requirements of biotechnological processes and products . Environmental research plan of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, 2005, Research Report 201 66 306, UBA-FB 000713, Umweltdaten.de (PDF; 1.4 MB) Status: 02.2005, accessed May 30, 2012.

Individual evidence

  1. ↑ O. Jolliet, P. Crettaz: Critical Surface-Time 95. A Life Cycle Impact Assessment Methodology Including Fate and Exposure . Ecole Polytechnique Federale de Lausanne, Lausanne 1997.
  2. ↑ W. Klöpffer, I. Renner, B. Tappeser, C. Eckelkamp, R. Dietrich: Life cycle assessment of genetically modified products as a basis for a comprehensive assessment of possible environmental effects . UBA Monograph 111, Federal Environment Agency, Vienna 1999.