To determine the combination of chemicals that is most likely to exhibit a synergistic effect, we need to understand what a synergistic effect is. A synergistic effect occurs when two or more substances interact in a way that their combined effect is greater than the sum of their individual effects. This can lead to increased toxicity or harmful effects. Let's analyze each option:
A: Alcohol and chlorinated solvents – Alcohols, such as ethanol, can potentiate the effects of other CNS depressants. Chlorinated solvents are known to have toxic effects on the liver and nervous system. When combined, they might increase the risk of liver damage or CNS depression, potentially exhibiting a synergistic effect.
B: Ethanol and methanol – Both ethanol and methanol are alcohols, but methanol is much more toxic. Ethanol is sometimes used as an antidote for methanol poisoning because it competes with methanol for metabolism by alcohol dehydrogenase. This combination is not likely to exhibit a synergistic effect in terms of increased toxicity; rather, ethanol can mitigate methanol's toxicity.
C: Benzene and carbon tetrachloride – Both benzene and carbon tetrachloride are known to be toxic to the liver and can cause other systemic toxicities. When combined, they may exhibit a synergistic effect due to their similar toxicological profiles, potentially leading to increased liver damage or other toxic effects.
D: Lead and mercury – Both lead and mercury are heavy metals that are toxic to the nervous system and other organs. However, their mechanisms of toxicity are different, and while they can both cause harm, they do not necessarily exhibit a synergistic effect. Their combined effects would be additive, rather than synergistic.
Considering the above analyses, option C, benzene and carbon tetrachloride, is the most likely combination to exhibit a synergistic effect, as both are liver toxins and their combined effect may be more severe than their individual effects.
GPT-4o's choice: C