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
Introduction
Bioaccumulation off natural toxins during the fish or any other organisms that can compose dining chains is an issue due to each other you’ll be able to negative effects into bacteria themselves therefore the possibility experience of predators, and individuals, that can consume this type of organisms. The main focus listed here is to your bioaccumulation inside the seafood, but similar prices affect bioaccumulation various other marine liquid-breathing bacteria, and in addition they get apply at air-breathing organisms such as wild birds and you can animals. Thus, a global step might have been introduced to test commercial chemical to possess its capacity to bioaccumulate step 1, 2 . Within so it effort, different sorts of bioaccumulation analysis and you can metrics are used to determine if and also to just what extent toxins is bioaccumulative. Comprehensive books is obtainable for the bioaccumulation out of medical and you will regulatory views, examples being the recommendations of the Barber step three, cuatro , Mackay and you will Fraser 5 , Arnot and you can Gobas six , Ehrlich ainsi que al. seven , Burkhard mais aussi al. 8 , and Gobas et al. 9 , the second summarizing the brand new results off a good SETAC-sponsored working area held for the 2008. Such or any other product reviews keeps pointed out the clear presence of multiple metrics of bioaccumulation that disagree within the definition, inside the regulating software, as well as in use by scientific area.
Our very own goal is to identify and you may talk about the matchmaking between 5 well-known bioaccumulation metrics to have aquatic organisms which have a viewpoint so you’re able to clarifying their cousin merits and you may usefulness having bioaccumulation tests. I basic temporarily determine and you may discuss the bioaccumulation metrics, following use a bulk equilibrium design to examine and measure the brand new dating between them. We seek to render novel information to your hidden techniques resulting from inside the bioaccumulation and provide suggestions for boosting and you can finding investigation for bioaccumulation examination.
BIOACCUMULATION METRICS
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 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 amor en linea 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.