Final answer:
The substances that are never included in the top ten substances on the priority list are likely 'polyaromatic hydrocarbons' as a category and 'petroleum products' as they represent broad groups of compounds rather than specific individual chemicals.
option d is the correct
Step-by-step explanation:
The student is asking which of the following substances is never included in the top ten substances on the priority list: mercury, benzo(b)fluoranthene, benzene, polyaromatic hydrocarbons, or petroleum products.
To provide an informed answer, we should refer to the Agency for Toxic Substances and Disease Registry (ATSDR) Substance Priority List or similar resources that identify substances based on frequency, toxicity, and potential for human exposure.
While benzene and mercury have been known to frequently make such lists due to their toxicity and widespread use, polyaromatic hydrocarbons (PAHs) like benzo(b)fluoranthene are also recognized for their potential risks. Moreover, 'petroleum products' is a broad category that includes a range of compounds, some of which may be on the priority list.
Given the broad nature of 'petroleum products,' which can encompass both toxic and non-toxic substances, and considering 'polyaromatic hydrocarbon' is a class of compounds rather than a specific one, it's most likely that these two options would not be individually listed in a top ten substances on a priority list. It's important to specify individual compounds when referring to priority lists.
The category 'polyaromatic hydrocarbon' includes many substances, some of which are likely to appear on such lists, but the general category itself wouldn't be. Petroleum products, as a broad category, would also likely include substances individually listed, but as a category, it won't feature on the top ten substances on a priority list of specific chemicals.