Five widely used metrics of bioaccumulation in fish are defined and discussed, namely the octanol–water partition coefficient (KOW), bioconcentration factor (BCF), bioaccumulation https://datingranking.net/chatango-review/ 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 regarding normal toxins when you look at the fish and other organisms that can constitute dining stores is a concern because of one another you are able to negative consequences toward bacteria by themselves and the potential for exposure to predators, and humans, that will eat these bacteria. The main focus let me reveal with the bioaccumulation for the fish, but similar principles connect with bioaccumulation in other aquatic drinking water-respiration bacteria, and in addition they get apply at sky-breathing bacteria such as for instance birds and you may mammals. Because of this, a major international step might have been introduced to evaluate industrial agents to have its capability to bioaccumulate step 1, 2 . As an element of it step, different sorts of bioaccumulation study and you will metrics are widely used to influence if or not and also to exactly what extent chemical compounds is actually bioaccumulative. Comprehensive literary works is obtainable on the bioaccumulation from scientific and you can regulatory viewpoints, advice being the recommendations of the Hairdresser step 3, cuatro , Mackay and you may Fraser 5 , Arnot and you can Gobas six , Ehrlich ainsi que al. seven , Burkhard ainsi que al. 8 , and you will Gobas ainsi que al. 9 , aforementioned summarizing the newest results off good SETAC-backed workshop held for the 2008. These types of or other critiques keeps mentioned the current presence of several metrics regarding bioaccumulation that disagree from inside the meaning, in regulating software, plus use because of the scientific area.
Our mission the following is in order to identify and you will discuss the relationships anywhere between 5 preferred bioaccumulation metrics to possess marine organisms which have a view so you can making clear the relative merits and you can applicability getting bioaccumulation tests. I first temporarily establish and discuss the bioaccumulation metrics, next incorporate a bulk equilibrium model to look at and assess brand new matchmaking between the two. I seek to render unique understanding towards the fundamental processes ensuing inside bioaccumulation and gives information to have improving and you may searching for data to possess bioaccumulation tests.
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.