What Do We Know About the Ecological Risk of Personal Care Product Ingredients?
Felix Ayala-Fierro, Henkel Consumer Goods
Personal care products (PCPs) have been used for many years, and demand for these products is growing as economies around the world, especially Asia, continue to grow. PCPs were a hot topic at the SETAC North America annual meeting in Long Beach. Following is a summary of the author’s observations about PCPs from that meeting.
The ingredients in PCPs reach the environment via a “down-the-drain” path. The amounts in ecosystems such as rivers and soils are directly related to the percent removed by waste water treatment plants. Degradation further reduces the amount found in ecosystems. Exposure to these ingredients can be determined using modeling programs but often require four sets of data: (1) per capita usage information, (2) accurate partitioning and reactivity data, (3) results from well designed monitoring programs and (4) predictions of fate and pathways of exposure from mass balance models.
Monitoring and modeling programs are frequently used in risk assessments. ScenAT is a geo-referenced exposure model used recently to predict exposure of PCP ingredients in freshwater ecosystems around the Asia 12 region. The predictions directly depend on grouping by “product affordability,” which may differ from other areas in the world.
SimpleTreat is a sewage treatment plant model used in European Union regulatory risk assessment to predict discharge into the environment. The model has been improved by addressing uncertainty of chemical input properties and variability observed in removal rates. A validation study with ten selected chemicals from PCP ingredients was favorable. The use of real data allows the transition from deterministic worst-case modeling to a more realistic approach.
A project is Rochester, Minn., collected water and sediment samples to characterize contaminants of emerging concern (CEC) profiles and land uses associated with sub-watersheds and identify CEC-land use “fingerprints” (unique profiles of chemical markers) to indicate the influence of a given land use on water quality. The impact on land may also be affected by solid waste deposition especially in developing countries which may lead to acute and long-term consequences for the environment in receiving sites. Measuring PCP ingredients in these areas is important to raise awareness in government, society and industry.
Environmental risk characterization has been conducted with some PCP ingredients. Fatty alcohols are one of the major surfactant classes used in PCP but are also synthesized naturally. The major contribution (84%) comes from naturally occurring terrestrial plants, therefore a risk assessment for a particular surfactant class should include a complete source characterization. The small component that may be attributed to discharges from waste water treatment plants appears to be substantially under the probable no-effects concentration for the free alcohols, based on quantitative structure–activity relationship (QSAR) approaches.
Triclosan (TCS) is used as antimicrobial in PCP and reaches soil via application of sludge-containing biosolids. Studies were conducted under OECD guidelines to determine the potential risk for the terrestrial environment. Results demonstrated that TCS poses minimal risk to earthworms (Eisenia fetida) and to the development of 10 species of terrestrial plants as measured in survival, emergence, shoot biomass and length, and normalcy. TCS also reaches the marine environment and has been recently found in parts-per-trillion levels in Singapore seawater in costal systems. Although it has been demonstrated that low levels do not have a significant impact on toxic end points, the authors continue to evaluate effects on physical stress.
The use of monitoring and modeling is key to understand the environmental risk of PCP ingredients. However, data developed under Good Manufacturing Practices should be preferred. A good model should list potential limitations and be transparent for all involved parties. The use of real data allows a more realistic approach including all potential sources of contaminants both natural and anthropogenic.
Author’s contact information: Felix.Ayala-Fierro@us.henkel.com
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