Maximum Acceptable Concentration MAC

According to guidelines published by the Ontario Ministry of the Environment in January 2001, the Maximum Acceptable Concentration (MAC) for Pb " in drinking water is 0.010 mg/L. The water in a community is contaminated with Pb " from an industrial source, at a concentration of 0.0800 mg/L. 

Levels for most metals and organics are well below the maximum acceptable concentrations (MAC) specified in Guidelines for the Canadian Drinking Water Quality (1978). However, the highest level of lead found in some localities is higher (79.7 /xg/L) than the MAC (50 Mg/L). 

Ion or compound Maximum Acceptable Concentration (MAC) (mg/L) Interim Maximum Acceptable Concentration (mg/L) Aesthetic Objectives (A0) (mg/L)... 

In 1990 there were 3 reports of the low level occurrence of benzene in beverages. Bottled mineral water was contaminated with benzene originated from an underground source of carbon dioxide which was inadequately carbon treated [23]. Two manufacturers found benzene in fmit flavoured mineral waters at levels greater than 5.0 pg/kg [24], The US EPA maximum contaminant level (MAE) for benzene is 0.005 mg/L [25] which is also the Canadian guideline as maximum acceptable concentration (MAC) in drinking water [26]. The manufacturers attributed the benzene to the presence of ascorbic acid and sodium benzoate in combination in their drink formations [27], omitting either of these additives eliminated the benzene. 

The sum for all organochlorinated pesticides identified in water (a, p, y-HCH, heptachlor, aldrin, DDE, dieldrin and DDT) usually exceeds the maximum acceptable concentration (MAC). 

This chapter assesses the combination of maximum acceptable concentrations (MACs) and product-specific bans (PSBs) used by regulators. First, it analyses whether this approach is near optimal , in the sense of approximating the ideal first best , in which a social planner has full knowledge of aU aspects of the problem, and in particular the damages associated with chemical use. ft then analyses the opportunities... 

In the early development of such limits, they were generally known as Maximum Allowable Concentrations or MACs, sometimes called Maximum Acceptable Concentrations, or Maximum Permissible Concentrations. 

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). 

The acceptable daily intakes set by the Joint Meeting on Pesticide Residues (JMPR) for cypermethrin, deltamethrin, and permethrin are 0-0.01 mg kg body weight, with acute oral reference doses for deltamethrin or permethrin of 0.05 mg kg bw. The National Institute for Occupational Safety and Health maximum allowable concentration (MAC) for pyrethrins at an 8 h time-weighted average is 5 mg m ... 

One accepted value of the maximum allowable concentration (MAC) of hydrogen sulfide to which a person can be exposed without injury to health is 20 ppm as set by the American Conference of Governmental Industrial Hygienists (ACGIH) (18). Although this level is not injurious to health, it does irritate the eyes. To prevent this irritation, a MAC of 5-10 ppm has been suggested (18). These two values were used to evaluate the relative toxicity of the hydrogen sulfide emissions in the preparation of the S-A-S mixes. 

Let the total stock of the resource at time the S f), with an initial level S,. The regulator sets a maximum acceptable concentration for the chemical so that, if it reaches this level in the resource, it is harmed indefinitely. This is equivalent to saying that the stock of the natural resource must not fall below S once the effective stock (S -S) is exhausted, the chemical is banned. The product-specific nature of the ban means that a MAC relates to each individual chemical once one chemical is banned, the next one to emerge on the market is assigned a firesh stock of resource (S — S). To keep the analysis simple and to highlight the strategic behaviour involved, it is assumed that the resource is non-renewable and there is no uncertainty. The dynamics of the natural resource stock canbe written as follows (where tdenotes time) ... 

In the early development of such limits, they were generally known as Maximum Allowable Concentrations or MAC S, sometimes called Maximum Acceptable Concentrations, or Maximum Permissible Concentrations. The early concept was that these were values which must not be exceeded in other words, they were truly maximum values. As the understanding of limits and the development of the philosophy for such limits grew, it was realized that short-term exposures to somewhat higher concentrations could be permitted without undue hami if the total exposure during the day was sufficiently below the maximum limit. This lead to the development of the concept of Threshold Limit Values (TLV s) by the ACGIH. 

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