How Many Chemicals in Commerce Have Been Analyzed in Environmental Media? A 50 Year Bibliometric Analysis
Level 4 - case-series / case-control
Cross-sectional bibliometric database survey (level assigned by non-clinical design analogy)
OpenAlex W4380853537 · doi:10.1021/acs.est.2c09353
What was done
The authors conducted a bibliometric survey of the CAS CAplus database using the indexing roles "analytical study" and "pollutant" across a 55-year historical window. They identified 19,776 CAS Registry Numbers (CASRNs) and mapped their occurrences across biological and environmental studies to assess how comprehensively commercial chemicals, priority lists, pharmaceuticals, and pesticides have been monitored.
What was found
The search yielded 19,776 unique CASRNs with 9.251 × 10^6 total counts over 55 years. Approximately 14,150 CASRNs corresponded to priority list substances, their close analogs, or transformation products. Research demonstrated heavy reporting bias: the top 100 most reported CASRNs accounted for 34% of the entire dataset. Substances listed on industrial chemical inventories in Europe, China, and the United States made up only about 5% of measured substances, whereas pharmaceuticals and current-use pesticides accounted for 50% to 60% of all CASRN counts between 2000 and 2015.
Why it matters
This study highlights a major blind spot in environmental surveillance: while tens of thousands of industrial chemicals are in commercial use, routine environmental testing repeatedly monitors a narrow subset of regulated priority compounds, pesticides, and pharmaceuticals.
Limits
The analysis relies entirely on CAplus indexing terminology and literature coverage, potentially omitting studies not indexed with specific analytical or pollutant flags. Publication frequency serves as a proxy for research attention rather than actual environmental risk, mass loading, or human exposure. Regulatory monitoring data held in private or non-indexed government databases were not evaluated.
Cited by
- context 50,000 new synthetic chemicals of unknown toxicology have been introduced into the environment.