MAC-EQS

Chronic toxicity data are preferred for deriving an annual average EQS (AA-EQS). Acute data are used to calculate a maximum acceptable concentration EQS (MAC-EQS) and can be used to derive the AA-EQS if insufficient chronic data are available, but an AA-EQS should not be derived exclusively on the basis of acute data. Guides to efficient decision making about the testing requirements for derivation of short- and long-term EQSs based on modes of action and other considerations were provided by Verhaar et al. (1992), de Wolf et al. (2005), and Hutchinson et al. (2006). 

There has been a large increase in recent years in the application of SSDs in ecotoxi-cology, as evidenced by the recent SETAC (Society of Environmental Toxicology and Chemistry) book by Posthuma et al. (2002). This approach is being or will shortly be applied in the European Union, Australia, United States, and Canada, with a general movement (where possible) toward the use of ECx in preference to the historical use of AFs and NOECs in deterministic PNEC calculations. The toxicity endpoint used will depend on the objective. For deriving a MAC-EQS, LC(EC)50 data are appropriate, while chronic NOECs (or preferably chronic ECx values, where available) are applicable for AA-EQSs. 

Commission, 2008). In this projected modification to the Directive, only 4 trace elements are listed Cd, Ni, Pb and Hg. For these elements, the values obtained in this study were compared with the maximum allowable concentrations (MAC-EQS) for inland surface waters when available (Table 4.5.2). In France, a Circulaire (2007) defines NQEp (which are the French translation of the European MAC-EQS). However, since there is still a need to evaluate the geochemical background for many trace elements in surface waters, it has to be borne in mind when comparing water quality data with NQEp values, that these are not yet the definitive values. Finally, data were compared with limits fixed for drinking waters (Decree, 2001). 

Class and name of substance Potential health effect from long-term exposure, (1) and (2) Common sources in drinking water, (1) and (2) US EPA DW-MCL (1) WHO DW-PV (2) EU DW-PV (3) EU AA-EQS Inland surface waters (4) EU MAC-EQS Inland surface waters (4)... 

Laboratoire de Chimie des Materiaux et Catalyse, Departement de Chimie, Faculte des Sciences de Tunis, Campus Universitaire Tunis ElManar 2092 Tunis-Tunisia. bInstitut Charles Gerhardt Montpellier, UMR 5253, CNRS-UM2-ENSCM-UM1, Eq. "Materiaux Avancespour la Catalyse et la Sante", ENSCM(MACS - Site la Galera), 8, Rue Ecole Normale, 34296 Montpellier Cedex 5, France. 

In what compliance with the stipulated legislation is concerned, only alachlor was found to exceed the EQS (MAC of 700 ng/L) in two of the samples investigated (HDAD, May 2 HEIMD, April 21) [29]. 

The ionic strength effect is not limited to ksv variation as described by eq. (22). The addition of large amounts of electrolytes may also modify the quencher solubility and thus its efficiency. This effect has been used by some authors, in systems very different from those examined in this work, in order to determine the association constant of the inhibitor salt (Mac, 1997 Mac and Tokarczyk, 1999) as the electrolyte concentration is increased, the quencher ion associates, so that the effective concentration of the inhibitor ion decreases, leading to a downward curvature of the Stern-Volmer plot. Such a curvature can be quantitatively related... 

Attachment of chlorosulfonated MPc by sulfonation and sulfonamide linkage to mac-roreticular polystyrenes led to a polymer containing 0.0027 to 0.035% (49), 50) (Eq. 19) Here, the MPc are mainly aggregated at the edges of the beads. The activity of the polymers for the oxidation of cyclohexene at 351 K compared with low molecular... 

A test of the usefulness of the dimerization model is provided by the ability of Eq. (1.3-43) to represent Mac Doug all s volumetric data for acetic acid vapor. The solid line in Fig. 1.3-3. gane rated from Eq. (1.3-45) with K = 380. providas an encellent fit of the data one concludes thet the dimerization model is consistent with the observed / VT behavior at 40°C. The apparent fugacity coefficient for noetic acid vapor, fonnd from Eq. (1-3-43) with , = [Pg.22]

Such functions are useful in the presentation of absorbance-time dependencies. The exponent m will take the values 1, 2, 1/2 and 3/2 in many cases. The disadvantage of these functions is that they contain the parameter. For this reason their use in practise would require extensive tabulations. Another possibility is to develop eq. (1.41) as a power series according to Mac Laurin [10,30-32]... 

This approximation gives better results than the Mac Laurin series, since eq. (3.66) represents the asymptote to the curve, eq. (1.41). The error stays below 1% above an absorbance = 4.7 (2.04 in decadic units). In the range of natural absorbance = 4 to = 4.7 an error less than 2% is obtained. 

Taylor series will yield better results than the Mac Laurin series, eq. (3.65). Beginning at or E one finds [28]... 

Thus, the results stated above demonstrated that Flory-Huggins interaction parameters described exactly enough interactions system for mac-romolecular coil in solution, controlling its fractal dimension value. The main problem at the Eq. (58) using with the purpose of prediction is the absence of the empirical parameter calculation technique [67],... 

From the Eq. (47) it follows, that P =Q =1.0 or the reaction of all initial substances is reached at D=1.50. This observation is easily explained. The mac-romolecular coil with dimension D <1.50 is called leaking [16] or trasparent [17], sinee for such coils their complete interpenetration concerning each other is realized. It is obvious, that in this case any reactive site of coil is accessible for reaction and this allows to obtain maximum possible conversion degree. Hence, the condition Qjj <1.0 for D >1.5 is due to nonleakaging ( opacity ) of macro-molecular coils [16, 17]. 

Hence, the adduced above results showed decisive influence of macromolecu-lar coil structure, characterized by its fractal dimension, on the formed copolymer type. The reason of this is obvious enough — whichever the number of active centres is and whichever their activity, is the access to them is controlled by mac-romolecular coil stracture, namely, the higher Dp is the more compact its structure is and the stronger its surface is screened, that decelerates reaction realization. Let us note one more important aspect — the Eq. (95) introduces the Kh temporal dependence. It is obvious, that the longer reaction duration t is the larger, Kh is at and the smaller — at reaction duration does not influence on copolymer type only at the condition i e., at completely statistical... 

Note that the term [1 — MaC(0 — C)] tends to avoid the vertical displacement (deformation) of the interface. For the temperature field, the boundary condition at the free surface, eq. (23), becomes... 

---