Question

Which of the following is/are true about Maximum Contaminant Level Goals (MCLGs)?

I. The MCLG for any contaminant that is regulated as a carcinogen is set to zero.

II. An average person weighing 70 kg (154 lb) could drink two liters (about two quarts) of water containing a contaminant at the MCGL level every day for 70 years without suffering any ill effects.

III. The Maximum Contaminant Level (MCL) set by the EPA may be higher than the MCLG to account for the financial and technical barriers that may make achieving these goals difficult.

IV. The MCLG for a contaminant is always set to zero because this is the best way to protect human health.

A: II only
B: I and II only
C: I, II, and III only
D: I, II, III, and IV

Answer 1

The true statements about Maximum Contaminant Level Goals are that for carcinogens, the MCLG is set to zero, one can safely consume water with a contaminant at the MCLG level for a lifetime, and MCL may be higher than MCLG due to practical considerations.

Step-by-step explanation:

The question examines the truths about Maximum Contaminant Level Goals (MCLGs). Here are the clarifications for each statement:

• Statement I: True. The MCLG for any contaminant regulated as a carcinogen is indeed generally set to zero to protect public health because there is no safe level of exposure.
• Statement II: True. MCLGs are set with a margin of safety in mind, such that an average person could consume water with a contaminant at the MCLG level without expected health risks over a long duration, typically assumed to be a lifetime (70 years).
• Statement III: True. The Maximum Contaminant Level (MCL) can be higher than the MCLG due to issues like financial and technical barriers. MCLs are enforceable levels that take into account the feasibility of water treatment and costs.
• Statement IV: False. Not all MCLGs are set to zero. They are set based on what is safe for human health, with some level of safety margin, except for those related to carcinogens where zero is the goal.

Given these explanations, the answer to the question is C: I, II, and III only.