Disinfection by-product

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Disinfection by-products (DNP) arise from chemical reactions between organic and inorganic substances in water during the water disinfection process .

By-products of chlorine-based disinfectants

Disinfectants such as chlorine and chloramine are strong oxidizing agents that are introduced into water to destroy pathogenic microbes , to oxidize taste and odor-forming compounds and to form a disinfectant residue so that water can safely reach the consumer from microbial contamination. These disinfectants can react with naturally occurring fulvic , humic , amino acids and other natural organics, as well as iodide and bromide ions , to create a range of DNPs , such as trihalomethanes (THM), haloacetic acids (HAAs), bromate , chlorite and so-called "resultant" DNP as halogen Nitromethane , haloacetonitriles , haloamides , Halogenfuranone , Iodsäuren as iodoacetic acid , Iodtrihalogenmethane , nitrosamines and others.

Chloramine has become a popular disinfectant in the US that has been shown to produce N- nitrosodimethylamine (NDMA), which is a potential human carcinogen , as well as highly genotoxic iodinated DNPs, such as iodoacetic acid, when iodide is present in the water source.

Residual chlorine and other disinfectants can also react further within the (waste) water network. Both through further reactions with dissolved natural organic substances and with biofilms present in the pipelines . In addition to the strong influence of the types of organic and inorganic substances in the spring water, the types and concentrations of DNP vary depending on the type of disinfectant used, the disinfectant dose, the concentration of natural organic material and bromide / iodide, the time since dosing (i.e. water aging) , Temperature and pH of the water.

In swimming pools where chlorine was used, levels of trihalomethanes were measured that are generally below the current EU standard for drinking water (100 micrograms per liter). Concentrations of various trihalomethanes (mainly chloroform) of up to 0.43 ppm have been measured. In addition, trichloramine has been detected in the air above swimming pools and is believed to increase asthma in professional swimmers. Trichloramine is formed by the reaction of urea (from urine and sweat) with chlorine and gives the indoor pool its unmistakable odor.

By-products of non-chlorine based disinfectants

Several strong oxidizing agents are used in the disinfection and treatment of drinking water, many of which also cause the formation of DNP. For example , ozone produces ketones , carboxylic acids and aldehydes, including formaldehyde . Bromide in spring water can be converted to bromate by chlorine (or hypochlorite) and ozone by hypobromite , a carcinogen that is regulated in the USA, as well as other brominated DNPs.

As the regulations for established DNPs such as THM and HAA are tightened, drinking water treatment plants will have to switch to alternative disinfection methods. This change will change the distribution of DNP classes.

Occur

DNPs are found in most drinking water supplies that have undergone chlorination , chlorination , ozonation, or treatment with chlorine dioxide . There are many hundreds of DNPs in treated drinking water and at least 600 have been identified. The low level of many of these DNPs, along with the analytical cost of testing water samples, means that in practice only a handful of DNPs are actually monitored. It is increasingly found that the genotoxicities and cytotoxicities of many DNPs that do not require monitoring (especially iodinated, nitrogen-containing DNPs) are comparatively much higher than the DNPs that are usually monitored in the developed world (THM and HAAs).

Health hazards

Epidemiological studies have examined the links between exposure to DNP in drinking water with cancer , adverse birth outcomes, and birth defects . Meta-analyzes and pooled analyzes from these studies have shown consistent associations for bladder cancer and babies born “small in relation to maturity” , but not for congenital abnormalities (birth defects). Miscarriages have also been reported in some studies. However, the presumably responsible agent is not known in the epidemiological studies because the number of DNPs in a water sample is high and exposure surrogates such as monitoring data of a specific by-product (often total trihalomethanes) are used instead of a more detailed exposure.

The World Health Organization has stated that the risk of death from pathogens is at least 100 to 1,000 times higher than the risk of cancer from disinfection by-products and that the risk of disease from pathogens is at least 10,000 to 1 million times higher than the risk of cancer from disinfection by-products.

Regulation and supervision

The U.S. Environmental Protection Agency has set Maximum Contaminant Levels (MCLs) for bromate, chlorite, haloacetic acids, and total trihalomethanes (TTHM). In Europe, the TTHM content was set at 100 micrograms per liter and the bromate content at 10 micrograms per liter according to the Drinking Water Directive. No guideline values ​​have been set for HAA in Europe. The World Health Organization has established guidelines for several DNPs, including bromates, bromodichloromethane, chlorate, chlorite, chloroacetic acid, chloroform, cyanogen chloride, dibromoacetonitrile, dibromloromethane, dichloroacetic acid, dichloroacetonitrile, NDMA, and trichloroacetic acid.

literature

  • Celia Henry Arnaud: The chemical reactions taking place in your swimming pool . In: Chemical & Engineering News . tape 94 , no. 31 , 2016, p. 28-32 (English, acs.org ).

Individual evidence

  1. ↑ a b c d e f g S. Richardson, M. Plewa, E. Wagner, R. Schoeny, D. Demarini: Occurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: A review and roadmap for research . In: Mutation Research / Reviews in Mutation Research . tape 636 , no. 1-3 , November 2007, pp. 178–242 , doi : 10.1016 / j.mrrev.2007.09.001 (English).
  2. ^ A b Susan D. Richardson, Francesca Fasano, J. Jackson Ellington, F. Gene Crumley, Katherine M. Buettner: Occurrence and Mammalian Cell Toxicity of Iodinated Disinfection Byproducts in Drinking Water . In: Environmental Science & Technology . tape 42 , no. 22 , November 15, 2008, ISSN  0013-936X , p. 8330-8338 , doi : 10.1021 / es801169k (English).
  3. ↑ Meri Koivusalo, Terttu Vartiainen: Drinking Water Chlorination By-Products And Cancer . In: Reviews on Environmental Health . tape 12 , no. 2 , ISSN  2191-0308 , doi : 10.1515 / REVEH.1997.12.2.81 (English).
  4. ^ Mark J. Nieuwenhuijsen, Mireille B. Toledano, Paul Elliott: Uptake of chlorination disinfection by products; a review and a discussion of its implications for exposure assessment in epidemiological studies . In: Journal of Exposure Science & Environmental Epidemiology . tape 10 , no. 6 , November 2000, ISSN  1559-0631 , p. 586-599 , doi : 10.1038 / sj.jea.7500139 (English).
  5. ↑ JA Beech, R Diaz, C Ordaz, B Palomeque: Nitrates, chlorates and trihalomethanes in swimming pool water. In: American Journal of Public Health . tape 70 , no. 1 , ISSN  0090-0036 , p. 79-82 , doi : 10.2105 / AJPH.70.1.79 (English).
  6. ↑ Judy S. LaKind, Susan D. Richardson, Benjamin C. Blount: The Good, the Bad, and the Volatile: Can We Have Both Healthy Pools and Healthy People? In: Environmental Science & Technology . tape 44 , no. 9 , 2010, ISSN  0013-936X , p. 3205–3210 , doi : 10.1021 / es903241k (English).
  7. ↑ Jerome O Nriagu: Encyclopedia of environmental health . Elsevier Science, Amsterdam (Netherlands) 2012, ISBN 978-1-78034-468-3 (English, credoreference.com [accessed February 11, 2019]).
  8. ↑ Michael J. Plewa, Mark G. Muellner, Susan D. Richardson, Francesca Fasano, Katherine M. Buettner: Occurrence, Synthesis, and Mammalian Cell Cytotoxicity and Genotoxicity of Haloacetamides: An Emerging Class of Nitrogenous Drinking Water Disinfection Byproducts . In: Environmental Science & Technology . tape 42 , no. 3 , 2008, p. 955-961 , doi : 10.1021 / es071754h (English).
  9. ^ CM Villanueva, KP Cantor, JO Grimalt, N. Malats, D. Silverman: Bladder Cancer and Exposure to Water Disinfection By-Products through Ingestion, Bathing, Showering, and Swimming in Pools . In: American Journal of Epidemiology . tape 165 , no. 2 , September 27, 2006, ISSN  0002-9262 , p. 148–156 , doi : 10.1093 / aje / kwj364 (English).
  10. ↑ N. Costet, CM Villanueva, JJK Jaakkola, M. Kogevinas, KP Cantor: Water disinfection by-products and bladder cancer: is there a European specificity? A pooled and meta-analysis of European case-control studies . In: Occupational and Environmental Medicine . tape 68 , no. 5 , May 1, 2011, ISSN  1351-0711 , p. 379-385 , doi : 10.1136 / oem.2010.062703 (English).
  11. ↑ Mark J. Nieuwenhuijsen, David Martinez, James Grellier, James Bennett, Nicky Best: Chlorination Disinfection By-Products in Drinking Water and Congenital Anomalies: Review and Meta-Analyzes . In: Environmental Health Perspectives . tape 117 , no. 10 , 2009, ISSN  0091-6765 , p. 1486–1493 , doi : 10.1289 / ehp.0900677 , PMID 20019896 (English).
  12. ↑ Kirsten Waller, Shanna H. Swan, Gerald DeLorenze, Barbara Hopkins: Trihalomethanes in Drinking Water and Spontaneous Abortion: . In: Epidemiology . tape 9 , no. 2 , 1998, ISSN  1044-3983 , pp. 134–140 , doi : 10.1097 / 00001648-199803000-00006 (English).
  13. ↑ David A Savitz, Microbial / Disinfection By-Products Research Council (US), AWWA Research Foundation, United States, Environmental Protection Agency: Drinking water disinfection by-products and pregnancy outcome . Awwa Research Foundation, Denver, CO 2005 (English, worldcat.org [accessed February 11, 2019]).
  14. ↑ D. Bevan: DISINFECTANTS AND DISINFECTION . In: Science . January 6, 1893, ISSN  0036-8075 , p. 298–299 , doi : 10.1126 / science.ns-21.539.298-a (English).
  15. ↑ Directive 2008/105 / EC of the European Parliament and of the Council of 16 December 2008 on environmental quality standards in the field of water policy and amending and subsequently repealing Council Directives 82/176 / EEC, 83/513 / EEC, 84/156 / EEC, 84/491 / EEC and 86/280 / EEC as well as amending Directive 2000/60 / EC . OJ L, 32008L0105, December 24, 2008 ( europa.eu [accessed February 11, 2019]).
  16. ^ World Health Organization Water, Sanitation and Health Team: Guidelines for drinking-water quality. Vol. 1, Recommendations . Geneva: World Health Organization, 2004, ISBN 978-92-4154638-6 (English, who.int [accessed February 11, 2019]).