Mathematical dating anywhere between metrics of chemical bioaccumulation into the fish

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 out of organic toxins from inside the fish or other organisms which can make-up dinner stores is a concern because of both you’ll be able to unfavorable effects towards bacteria on their own in addition to possibility of exposure to predators, also individuals, that consume this type of bacteria. The main focus is towards the bioaccumulation in the fish, however, similar prices apply at bioaccumulation in other marine liquid-breathing organisms, and in addition they can get connect with heavens-respiration bacteria like birds and you will mammals. Consequently, an international step has been introduced to evaluate commercial chemical compounds to own its capacity to bioaccumulate 1, dos . Within so it effort, distinct bioaccumulation investigation and you may metrics are used to dictate whether or not also to what the amount agents try bioaccumulative. Detailed literature is available on the bioaccumulation of scientific and you may regulating perspectives, examples being the studies by the Barber 3, cuatro , Mackay and you can Fraser 5 , Arnot and you can Gobas six , Ehrlich ainsi que al. seven , Burkhard et al. 8 , and you can Gobas ainsi que al. 9 , the second summarizing the fresh conclusions away from good SETAC-backed working area held inside 2008. Such or other analysis has actually talked about the clear blued profile examples presence of numerous metrics out-of bioaccumulation you to definitely disagree from inside the meaning, for the regulatory application, plus in adoption by the scientific community.

The objective here is so you can describe and you can talk about the relationships anywhere between 5 preferred bioaccumulation metrics having marine organisms with a viewpoint to help you making clear its relative deserves and you can applicability having bioaccumulation examination. I first briefly determine and you will discuss the bioaccumulation metrics, following pertain a bulk equilibrium design to look at and you can quantify the new relationship between the two. We attempt to bring unique wisdom to the hidden process ensuing in the bioaccumulation and offer guidance to have improving and you will seeking study to have 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 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.

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