Five widely used metrics of bioaccumulation in fish are defined and discussed, namely the octanol–water partition coefficient (KOW), bioconcentration factor (BCF), bioaccumulation factor (BAF), biomagnification factor (BMF), and trophic magnification factor (TMF). Algebraic relationships between these metrics are developed and discussed using conventional expressions for chemical uptake from water and food and first-order losses by respiration, egestion, biotransformation, and growth dilution. Two BCFs ely as an equilibrium partition coefficient KFW or as a nonequilibrium BCFK in which egestion losses are included. Bioaccumulation factors are shown to be the product of the BCFK and a ely, the diet-to-water concentration ratio and the ratio of uptake rate constants for respiration and dietary uptake. Biomagnification factors are shown to be proportional to the lipid-normalized ratio of the predator/prey values of BCFK and the ratio of the equilibrium multipliers. Relationships with TMFs are also discussed. The effects of chemical hydrophobicity, biotransformation, and growth are evaluated by applying the relationships to a range of illustrative chemicals of varying KOW in a linear 4-trophic-level food web with typical values for uptake and loss rate constants. The roles of respiratory and dietary intakes are demonstrated, and even slow rates of biotransformation and growth can significantly affect bioaccumulation. The BCFKs and the values of M can be regarded as the fundamental determinants of bioaccumulation and biomagnification in aquatic food webs. Analyzing data from food webs can be enhanced by plotting logarithmic lipid-normalized concentrations or fugacities as a linear function of trophic level to deduce TMFs. Implications for determining bioaccumulation by laboratory tests for regulatory purposes are discussed. Environ Toxicol Chem 2013;–1466. © 2013 SETAC
Bioaccumulation regarding organic chemicals from inside the fish and other organisms which can form dining organizations is a concern on account of one another you can easily unfavorable outcomes towards organisms on their own and also the possibility connection with predators, plus people, that eat these types of organisms. The focus here’s into bioaccumulation inside seafood, but equivalent values apply at bioaccumulation in other aquatic h2o-respiration organisms, and they also will get apply to air-respiration organisms such as for example birds and you may animals. Because of this, a major international step could have been introduced to test commercial toxins getting their power to bioaccumulate 1, dos . As part of so it step, different sorts of bioaccumulation analysis and metrics are acclimatized to determine whether and also to exactly what extent chemical substances is bioaccumulative. Comprehensive literature is obtainable on the bioaccumulation out of medical and regulating point of views, advice being the critiques from the Barber step 3, cuatro , Mackay and you can Fraser 5 , Arnot and you may Gobas six , Ehrlich et al. eight , Burkhard et al. 8 , and you will Gobas et al. 9 , the second summarizing this new results from an excellent SETAC-backed workshop kept inside 2008. This type of or any other ratings have pointed out the existence of multiple metrics of bioaccumulation one to differ in the meaning, inside regulating application, plus in adoption by scientific community.
Our purpose listed here is to help you describe and you may talk about the relationship between 5 well-known bioaccumulation metrics to possess aquatic organisms that have a standpoint in order to clarifying the cousin deserves and applicability to own bioaccumulation tests. I very first temporarily describe and discuss the bioaccumulation metrics, next implement a size harmony model to look at and you will assess the latest matchmaking among them. We seek to give book understanding into fundamental procedure ensuing from inside the bioaccumulation and provide recommendations to have improving and in search of study for bioaccumulation tests.
For the current analysis, we define and describe 5 common metrics for assessing bioaccumulation. Differences exist in the definitions and usage of these terms; however, the definitions given here are casualdates hookup used to develop mathematical relationships in the next section. The octanol–water partition coefficient (KOW) is widely used as an indicator of hydrophobicity and thus the partitioning of a chemical from water into lipids and other organic phases such as protein 10 . The KOW is primarily controlled by the solubility of the substance in water, because the solubility of neutral, liquid nonpolar organic chemicals in octanol is relatively constant. A log KOW value of 5 is often used as a bioaccumulation assessment criterion; however, depending on the regulatory program, lower values are also used to categorize bioaccumulation potential. Whereas KOW gives a reasonable and conservative estimate of lipid–water partitioning for nonpolar hydrophobic substances 11 , it may not accurately simulate partitioning for more polar and ionogenic organic chemicals and other chemical classes such as organofluorines and silicones. Direct empirical measurement is essential in such cases.