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Measures of pollutant concentration

January 01, 1970

Measures of pollutant concentration are used to determine risk assessment in public health.

Industry is continually synthesizing new chemicals, the regulation of which requires evaluation of the potential danger for human health and the environment. Risk assessment is nowadays considered essential for making these decisions on a scientifically sound basis.

Measures or defined limits include:

No-effect concentration edit

No-effect concentration (NEC) is a risk assessment parameter that represents the concentration of a pollutant that will not harm the species involved, with respect to the effect that is studied. It is often the starting point for environmental policy.[2]

There is not much debate on the existence of an NEC,[3] but the assignment of a value is another matter. Current practice consists of the use of standard tests. In the standard tests groups of animals are exposed to different concentrations of chemicals and different effects such as survival, growth or reproduction are monitored. These toxicity tests typically result in a no-observed-effect concentration (NOEC, also called a no-observed-effect level, or NOEL). This NOEC has been severely criticized on statistical grounds by several authors[4] and it was concluded that the NOEC should be abandoned.[5]

ECx edit

A proposed alternative is the use of so-called ECx – the concentration(s) showing x% effect (e.g. an EC50 in a survival experiment indicates the concentration where 50% of the test animals would die in that experiment). ECx concentrations also have their problems in applying them to risk assessment. Any other value for x other than zero may give the impression that an effect is accepted, and this is in conflict with the aim of maximally protecting the environment.[6] In addition ECx values do depend on the exposure time.[7] ECx values for survival decrease for increasing exposure time, until equilibrium has been established. This is because effects depend on internal concentrations,[8] and that it takes time for the compound to penetrate the body of test organisms. However, sub-lethal endpoints (e.g., body size, reproductive output) may reveal less predictable effect patterns in time.[9]

The shape of the effect patterns over time depends on properties of the test compound, properties of the organism, the endpoint considered and the dimensions in which the endpoint is expressed (e.g., body size or body weight; reproduction rate or cumulative reproduction).

Biology-based edit

Biology-based methods not only aim to describe observed effects, but also to understand them in terms of underlying processes such as toxicokinetics, mortality, feeding, growth and reproduction (Kooijman 1997). This type of approach starts with the description of the uptake and elimination of a compound by an organism, as an effect can only be expected if the compound is inside the organism, and where the no-effect-concentration is one of the modeling parameters. As the approach is biologically based it is also possible by using the dynamic energy budget theory[10] to incorporate multiple stressors (e.g. effects of food restriction, temperature, etc.)[11] and processes that are active under field conditions (e.g. adaptation, population dynamics, species interactions, life cycle phenomena, etc.).[12] The effects of these multiple stressors are excluded in the standard test procedures by keeping the local environment in the test constant. It is also possible to use these parameter values to predict effects at longer exposure times, or effects when the concentration in the medium is not constant. If the observed effects include those on survival and reproduction of individuals, these parameters can also be used to predict effects on growing populations in the field.[13]

References edit

Inline edit

  1. ^ thefreedictionary.com/AOEL Retrieved on June 19, 2009
  2. ^ Bruijn et al., 1997, Chen & Selleck 1969
  3. ^ Van Straalen 1997, Crane and Newman 2000
  4. ^ Suter 1996, Laskowski 1995, Kooijman 1996, Van der Hoeven 1997
  5. ^ OECD Document No 54 of "Series on Testing Assessment", 2006
  6. ^ Bruijn et al. 1997
  7. ^ Kooijman 1981, Jager et al. 2006
  8. ^ Kooijman 1981, Péry et al. 2001a
  9. ^ Alda Alvarez et al. 2006
  10. ^ Kooijman, 2000
  11. ^ Heugens, 2001, 2003
  12. ^ Sibly and Calow (1989)
  13. ^ Kooijman 1997, Hallam et al. 1989

Bibliography edit

  • Alda Alvarez, O., Jager, T., Nunez Coloa, B. and Kammenga, J.E. (2006). Temporal dynamics of effect concentrations. Environ. Sci. Technol. 40:2478-2484.
  • Bruijn J.H.M. and Hof M. (1997) – How to measure no effect. Part IV: how acceptable is the ECx from an environmental policy point of view? Environmetrics, 8: 263 – 267.
  • Chen C.W. and Selleck R.E. (1969) - A kinetic model of fish toxicity threshold. Res. J. Water Pollut. Control Feder. 41: 294 – 308.
  • Straalen N.M. (1997) – How to measure no effect II: Threshold effects in ecotoxicology. Environmetrics, 8: 249 – 253.
  • Crane M. and Newman M.C. (2000) – What level of effect is a no observed effect? Environmental Toxicology and Chemistry, vol 19, no 2, 516 – 519
  • Suter G.W. (1996) – Abuse of hypothesis testing statistics in ecological risk assessment, Human and ecological risk assessment 2 (2): 331-347
  • Laskowski R. (1995) - Some good reasons to ban the use of NOEC, LOEC and related concepts in ecotoxicology. OIKOS 73:1, pp. 140–144
  • Hoeven N. van der, Noppert, F. and Leopold A. (1997) – How to measure no effect. Part I: Towards a new measure of chronic toxicity in ecotoxicology. Introduction and workshop results. Environmetrics, 8: 241 – 248.
  • OECD, Document No 54 of "Series on Testing Assessment", 2006. Current approaches in the statistical analysis of ecotoxicity data: a guidance to application
  • Kooijman S.A.L.M. (1981) - Parametric analyses of mortality rates in bioassays. Water Res. 15: 107 – 119
  • T. Jager, Heugens E. H. W. and Kooijman S. A. L. M. (2006) Making sense of ecotoxicological test results: towards process-based models. Ecotoxicology, 15:305-314,
  • Péry A.R.R., Flammarion P., Vollat B., Bedaux J.J.M., Kooijman S.A.L.M. and Garric J. (2002) - Using a biology-based model (DEBtox) to analyse bioassays in ecotoxicology: Opportunities & recommendations. Environ. Toxicol. & Chem., 21 (11): 2507-2513
  • Kooijman S.A.L.M. (1997) - Process-oriented descriptions of toxic effects. In: Schüürmann, G. and Markert, B. (Eds) Ecotoxicology. Spektrum Akademischer Verlag, 483 - 519
  • Kooijman S.A.L.M. (2000) - Dynamic Energy and Mass Budgets in Biological Systems. Cambridge University Press
  • Heugens, E. H. W., Hendriks, A. J., Dekker, T., Straalen, N. M. van and Admiraal, W. (2001) - A review of the effects of multiple stressors on aquatic organisms and analysis of uncertainty factors of use in risk assessment. Crit. Rev Toxicol. 31: 247-284
  • Heugens, E. H. W., Jager, T., Creyghton, R., Kraak, M. H. S., Hendriks, A. J., Straalen, N. M. van and Admiraal. W. (2003) - Temperature-dependent effects of cadmium on Daphnia magna: accumulation versus sensitivity. Environ. Sci. Technol. 37: 2145-2151.
  • Sibly R.M. and Calow P. (1989)- A life cycle theory of responses to stress. Biological Journal of the Linnean Society 37 (1-2): 101-116
  • Hallam T.G., Lassiter R.R. and Kooijman S.A.L.M. (1989) - Effects of toxicants on aquatic populations. In: Levin, S. A., Hallam, T. G. and Gross, L. F. (Eds), Mathematical Ecology. Springer, London: 352 – 382

January 01, 1970
measures, pollutant, concentration, used, determine, risk, assessment, public, health, industry, continually, synthesizing, chemicals, regulation, which, requires, evaluation, potential, danger, human, health, environment, risk, assessment, nowadays, considere. Measures of pollutant concentration are used to determine risk assessment in public health Industry is continually synthesizing new chemicals the regulation of which requires evaluation of the potential danger for human health and the environment Risk assessment is nowadays considered essential for making these decisions on a scientifically sound basis Measures or defined limits include no observed adverse effect level NOAEL also called no effect concentration NEC no observed effect concentration NOEC or similarly lowest observed adverse effect level LOAEL acceptable operator exposure level AOEL 1 ECx in percentage Contents 1 No effect concentration 2 ECx 3 Biology based 4 References 4 1 Inline 4 2 BibliographyNo effect concentration editNo effect concentration NEC is a risk assessment parameter that represents the concentration of a pollutant that will not harm the species involved with respect to the effect that is studied It is often the starting point for environmental policy 2 There is not much debate on the existence of an NEC 3 but the assignment of a value is another matter Current practice consists of the use of standard tests In the standard tests groups of animals are exposed to different concentrations of chemicals and different effects such as survival growth or reproduction are monitored These toxicity tests typically result in a no observed effect concentration NOEC also called a no observed effect level or NOEL This NOEC has been severely criticized on statistical grounds by several authors 4 and it was concluded that the NOEC should be abandoned 5 ECx editA proposed alternative is the use of so called ECx the concentration s showing x effect e g an EC50 in a survival experiment indicates the concentration where 50 of the test animals would die in that experiment ECx concentrations also have their problems in applying them to risk assessment Any other value for x other than zero may give the impression that an effect is accepted and this is in conflict with the aim of maximally protecting the environment 6 In addition ECx values do depend on the exposure time 7 ECx values for survival decrease for increasing exposure time until equilibrium has been established This is because effects depend on internal concentrations 8 and that it takes time for the compound to penetrate the body of test organisms However sub lethal endpoints e g body size reproductive output may reveal less predictable effect patterns in time 9 The shape of the effect patterns over time depends on properties of the test compound properties of the organism the endpoint considered and the dimensions in which the endpoint is expressed e g body size or body weight reproduction rate or cumulative reproduction Biology based editBiology based methods not only aim to describe observed effects but also to understand them in terms of underlying processes such as toxicokinetics mortality feeding growth and reproduction Kooijman 1997 This type of approach starts with the description of the uptake and elimination of a compound by an organism as an effect can only be expected if the compound is inside the organism and where the no effect concentration is one of the modeling parameters As the approach is biologically based it is also possible by using the dynamic energy budget theory 10 to incorporate multiple stressors e g effects of food restriction temperature etc 11 and processes that are active under field conditions e g adaptation population dynamics species interactions life cycle phenomena etc 12 The effects of these multiple stressors are excluded in the standard test procedures by keeping the local environment in the test constant It is also possible to use these parameter values to predict effects at longer exposure times or effects when the concentration in the medium is not constant If the observed effects include those on survival and reproduction of individuals these parameters can also be used to predict effects on growing populations in the field 13 References editInline edit thefreedictionary com AOEL Retrieved on June 19 2009 Bruijn et al 1997 Chen amp Selleck 1969 Van Straalen 1997 Crane and Newman 2000 Suter 1996 Laskowski 1995 Kooijman 1996 Van der Hoeven 1997 OECD Document No 54 of Series on Testing Assessment 2006 Bruijn et al 1997 Kooijman 1981 Jager et al 2006 Kooijman 1981 Pery et al 2001a Alda Alvarez et al 2006 Kooijman 2000 Heugens 2001 2003 Sibly and Calow 1989 Kooijman 1997 Hallam et al 1989 Bibliography edit Alda Alvarez O Jager T Nunez Coloa B and Kammenga J E 2006 Temporal dynamics of effect concentrations Environ Sci Technol 40 2478 2484 Bruijn J H M and Hof M 1997 How to measure no effect Part IV how acceptable is the ECx from an environmental policy point of view Environmetrics 8 263 267 Chen C W and Selleck R E 1969 A kinetic model of fish toxicity threshold Res J Water Pollut Control Feder 41 294 308 Straalen N M 1997 How to measure no effect II Threshold effects in ecotoxicology Environmetrics 8 249 253 Crane M and Newman M C 2000 What level of effect is a no observed effect Environmental Toxicology and Chemistry vol 19 no 2 516 519 Suter G W 1996 Abuse of hypothesis testing statistics in ecological risk assessment Human and ecological risk assessment 2 2 331 347 Laskowski R 1995 Some good reasons to ban the use of NOEC LOEC and related concepts in ecotoxicology OIKOS 73 1 pp 140 144 Hoeven N van der Noppert F and Leopold A 1997 How to measure no effect Part I Towards a new measure of chronic toxicity in ecotoxicology Introduction and workshop results Environmetrics 8 241 248 OECD Document No 54 of Series on Testing Assessment 2006 Current approaches in the statistical analysis of ecotoxicity data a guidance to application Kooijman S A L M 1981 Parametric analyses of mortality rates in bioassays Water Res 15 107 119 T Jager Heugens E H W and Kooijman S A L M 2006 Making sense of ecotoxicological test results towards process based models Ecotoxicology 15 305 314 Pery A R R Flammarion P Vollat B Bedaux J J M Kooijman S A L M and Garric J 2002 Using a biology based model DEBtox to analyse bioassays in ecotoxicology Opportunities amp recommendations Environ Toxicol amp Chem 21 11 2507 2513 Kooijman S A L M 1997 Process oriented descriptions of toxic effects In Schuurmann G and Markert B Eds Ecotoxicology Spektrum Akademischer Verlag 483 519 Kooijman S A L M 2000 Dynamic Energy and Mass Budgets in Biological Systems Cambridge University Press Heugens E H W Hendriks A J Dekker T Straalen N M van and Admiraal W 2001 A review of the effects of multiple stressors on aquatic organisms and analysis of uncertainty factors of use in risk assessment Crit Rev Toxicol 31 247 284 Heugens E H W Jager T Creyghton R Kraak M H S Hendriks A J Straalen N M van and Admiraal W 2003 Temperature dependent effects of cadmium on Daphnia magna accumulation versus sensitivity Environ Sci Technol 37 2145 2151 Sibly R M and Calow P 1989 A life cycle theory of responses to stress Biological Journal of the Linnean Society 37 1 2 101 116 Hallam T G Lassiter R R and Kooijman S A L M 1989 Effects of toxicants on aquatic populations In Levin S A Hallam T G and Gross L F Eds Mathematical Ecology Springer London 352 382 Retrieved from https en wikipedia org w index php title Measures of pollutant concentration amp oldid 1125074543, wikipedia, wiki, book, books, library,

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