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Applications of Equilibrium Thermodynamics
Published in Kalliat T. Valsaraj, Elizabeth M. Melvin, Principles of Environmental Thermodynamics and Kinetics, 2018
Kalliat T. Valsaraj, Elizabeth M. Melvin
Mackay (1991) proposed a term “fugacity capacity,” Z that related fugacity (of any phase expressed in Pa) to concentration (expressed in mol m−3). Thus, Zmol m−3Pa−1=Cmol m−3fPa The value of Z depends on a number of factors such as identity of the solute, nature of the environmental compartment, temperature T, and pressure P. A fugacity capacity can be defined for each environmental compartment (Table 3.2). In order to obtain the value of Z, knowledge of other equilibrium relationships between phases (“partition coefficients”) is required. These relationships will be described in detail later in this chapter. Suffice it to say, at this point the partition coefficients are to be either experimentally determined or estimated from correlations.
Basic Concepts
Published in J. Mark Parnis, Donald Mackay, Multimedia Environmental Models, 2020
Fugacity is directly related to concentration by a proportionality constant Z called a “fugacity capacity” or “Z-value”, i.e.: C=Zf
Implications of toxicity testing for health risk assessment of vapor-phase and PM2.5-bound polycyclic aromatic hydrocarbons during the diesel engine combustion
Published in Human and Ecological Risk Assessment: An International Journal, 2022
Guan-Fu Chen, Ying-Chi Lin, Yuan-Chung Lin, Chia-Chi Wang, Wei-Hsiang Chen
Understanding the fates of the PAHs after the emission such as advection, diffusion, and dispersion among different environmental compartments is one of the keys to exposure and risk assessment. The fugacity model is a method useful to predict the distribution of a compound in a complex multi-media environment by estimating the potential of transferring between the media with mass balance, as listed in Equation (1) (Mackay and Paterson 1991; Peijnenburg and Struijs 2006; Zhang et al. 2015). where Vi is the volume of a given environmental medium i (m3); f is the fugacity quantifying the potential of a compound for escaping from the medium i (Pa); Z is the fugacity capacity of the medium i (mole/m3–Pa); Ei is the emission rate of the compound (mole/h); Dji is the transport coefficient of the compound from medium j to medium i (mole/h–Pa); and Dti is the decay rate of the compound in medium i (mole/hr–Pa).
Uptake/release of organic contaminants by microplastics: A critical review of influencing factors, mechanistic modeling, and thermodynamic prediction methods
Published in Critical Reviews in Environmental Science and Technology, 2022
Domenica Mosca Angelucci, M. Concetta Tomei
With the objective of evaluating the behavior of chemicals in the environment and their distribution in the different phases (including air, water and sediments), Mackay and Paterson (1981) proposed a simple methodology based on the fugacity evaluation. Known that the fugacity is linearly related to the concentration for “dilute systems” which are representative of the low concentrations generally applying to contaminants in environmental matrices, they defined a fugacity (f)-concentration (C) relationship as function of the “fugacity capacity constant Z”: where Z (expressed in units of mol/m3 atm) quantifies the capacity of the phase (solid, liquid, gas) for fugacity (atm), and at a given fugacity, C (mol/m3) is proportional to Z. In other words, toxic compounds tend to accumulate in phases where Z is high. As the fugacity, Z depends on temperature, pressure, the nature of the substance, and the medium in which the contaminant is present, while the Z dependence on the concentration is negligible at high dilutions. Knowing the Z value of the contaminant for each environmental phase, allows evaluating its distribution: highest concentrations are reached where Z is the highest. Equilibrium conditions are expressed by the equality of fugacities, and the Z ratio in the two phases gives the concentration ratio and the contaminant distribution.
Recent advances in research on cyclic volatile methylsiloxanes in sediment, soil and biosolid: a review
Published in Chemistry and Ecology, 2018
Maocai Shen, Yaxin Zhang, Ye Tian, Guangming Zeng
The trophic magnification factors (TMFs) are evaluations of the average variation in contaminant concentrations, normalised for fugacity capacity, while transferring from one trophic level up to the higher in the food web. They are different with biomagnification factors (BMFs), which are used to individual species and measured from the slope of a regression between the target compounds concentrations and trophic level of organisms in the food web [44]. Powell et al. reported field BMFs accounting to the detection of a marine food web; the BMF values of herring and shrimp were 1.0 and 1.2 for D4, 0.2 and 0.8 for D5, 0.9 and 1.75 for D6, respectively, indicating D4 and D6 are bioaccumulative which mean BMF was >1 [64]. Accounting to the TMF, Powell et al. investigated cVMS concentrations at different trophic status in a freshwater food web and a marine food web. The TMF values for D5 were measured to be <1 in the benthic freshwater food web of Lake Pepin, Mississippi [101], and in the marine food web of the Oslofjord, Norway [64], but to be >1 in Lake Mjøsa and in Lake Randsfjorden, Norway [44,45]. Compared with other matters possessing stronger bioaccumulation, there was a strange phenomenon that with the increasing trophic status in a food web, the concentrations of cVMS significantly decreased. Some scholars believed that cVMS had no significant bioaccumulate within high trophic level organisms, but had some potential to bioaccumulate within low trophic level [86]. In a recent report by Powell et al., TMFs were less than 1.0 in the pelagic marine food webs in Tokyo Bay calculated by slopes of ordinary least-squares regression models and bootstrap regression models [46]. The author also concluded that there was a biodilution of cVMS not biomagnification in Tokay Bay and biodilution was unlikely related to the food webs. The reasons caused by these results as follows: (1) the sampling collections in these findings were in different ecosystem, different species and different food webs; some species are sensitive to target chemicals, but others are insensitive to this chemicals. In a study reported by Borgå et al., concentrations of cVMS in the higher level predators were obviously variable than in other studies [45]; (2) some studies used a part of sample such as muscles, livers and lung to estimate the TMFs, but in other reports, measurements were performed in whole sample; (3) the measurement methodology was different in these studies. Consequently, to guarantee the protection is needed for benthic and pelagic invertebrate consumers in food webs, and the long-term environmental monitoring and the assessment of bioaccumulation should be studied future.