Almost every personal care product contains fragrance, whether natural or synthetic. Unfortunately, the characteristics that make a chemical useful as a fragrance are often the same ones that can cause them to have an environmental impact. The types of chemicals that smell nice typically have some toxicity to aquatic life, and the fragrances that last all day are usually chemicals that are not readily biodegradable.
However, there are a few factors that make fragrances particularly difficult to evaluate for their potential environmental impact.
Exact fragrance mixtures are often confidential trade secrets. While other chemicals have to be listed individually, chemicals that are used as fragrances can usually just be listed as “fragrance” or “parfum”. This provides no indication of what the chemicals are. If there is a chance that the fragrance is synthetic, I assume that there is a chance that the chemicals could be chemicals of high concern.
Companies usually identify when a fragrance is from natural sources. Although the smell of natural fragrances often does not last as long as that of synthetic fragrances, this is a good sign for the environment – it suggests that the chemicals do break down relatively quickly and are likely to be readily biodegradable. If a chemical is readily biodegradable, it is unlikely to be a chemical of high concern.
However, natural fragrances are usually a mix of plant extracts or essential oils. Although it is becoming common to list the plants that the fragrances are extracted from, it often is not really clear what the exact chemicals are. This can make it difficult to confirm whether they are readily biodegradable, and if they are toxic to aquatic life.
The types of plant extracts and essential oils used as fragrances are also often exempt from regulations requiring manufacturers to provide information on environmental impacts. This means that there is often little incentive or funding to complete the tests that scientists rely on to work out how the chemicals might impact the environment. As a result, there is less public information on these ingredients.