Country‐Specific Environmental Risks of Fragrance Encapsulates Used in Laundry Care Products

Abstract

Fragrance encapsulates (FEs) are designed to deliver fragrance components, notably in laundry care products. They are made of thermoset polymeric shells surrounding the fragrance content. These materials enter the environment mainly during laundry washing, but little is known about their distribution in and impact on the environment. The aim of the present study was to estimate the environmental concentrations of FE shells in freshwater, sediment, and soil compartments for 34 selected countries and to compare them with ecotoxicological effects. Probabilistic material flow analysis was used to estimate worst-case predicted environmental concentrations (PECs). The lowest freshwater PEC was predicted for Finland (0.00011 µg/L) and the highest for Belgium (0.13 µg/L). Accumulation of FE shells between 2010 and 2019 was considered for sediments and sludge-treated soils. The PECs in sediments ranged from 3.0 µg/kg (Finland) to 3400 µg/kg (Belgium). For sludge-treated soil, the concentration was estimated to be between 0 (Malta and Switzerland) and 3600 µg/kg (Vietnam). Ecotoxicological tests showed no effects for FE shells at any tested concentration (up to 2700 µg/L freshwater, 5400 µg/kg sediment, and 9100 µg/kg soil), thus not allowing derivation of a predicted-no-effect concentration (PNEC). Therefore, to characterize the environmental risks, the PEC values were compared with highest-observed-no-effect concentrations (HONECs) derived from ecotoxicological tests. The PEC/HONEC ratios were 9.3 × 10 -6 , 0.13, and 0.04 for surface waters, sediments, and sludge-treated soils, respectively, which are much below 1, suggesting no environmental risk. Because the PEC values constitute an upper boundary (no fate considered) and the HONEC values represent a lower boundary (actual PNEC values based on NOECs will be higher), the current risk estimation can be considered a precautionary worst-case assessment.

Are Fragrance Encapsulates Taken Up by Aquatic and Terrestrial Invertebrate Species?

“…The same slurry preparation with double-labeling of shells and content was used for the water exposures. However, the highest water concentration estimated by Cai et al (2021) was only 0.13 µg/L, in Belgium. This is approximately a factor of 25,000 times lower than the tested concentrations for the amphipod and the bivalve, but this high concentration was necessary to allow detection of any potential uptake from the water column.…”

“…The concentration in soil of 50 mg/kg (slurry containing 7% of shells) used in tests with earthworms corresponds to the highest worldwide concentration of shells (3,600 µg/shells) in sludge-treated soil as estimated by Cai et al (2021). The same slurry preparation with double labelling of shells and content was used for the water exposures.…”

“…Also, translocation of microplastics to the circulatory system has been observed in this mussel species after 3 h of exposure to 3‐ and 9.6‐µm polystyrene particles at 0.51 g/L (Browne et al, 2008). While the fate of fragrance encapsulates in the environment has been modeled (Cai et al, 2021), so far a differentiated investigation on the eventual uptake of fragrance encapsulates in organisms is not available.…”

“…After use, fragrance encapsulates are generally released via the sewer to reach the sewage‐treatment plant (STP) or released directly via the gray water into the environment and represent <0.03% of the released microplastics, as calculated by Cai et al (2021). Unlike the large majority of the thermoplastic particles (low‐ and high‐density polyethylene, diphenyl ethylenes, and polypropylene) which are rigid particles of various sizes and shapes with a density <1 g/cm 3 that tend to float and may enter the aquatic environment suspended in effluents (Carr et al, 2016), fragrance encapsulates with a density >1 g/cm 3 have the tendency to sink in the water column.…”

“…On average in Europe and North America, 30 and 50%, respectively, of the STP‐generated sludge is used as fertilizer for agricultural purposes and in Ireland even >70% (Coors et al, 2016; Corradini et al, 2019). Therefore, this practice may represent a source of fragrance encapsulates which are potentially ingested by terrestrial organisms (Schmidt et al, 2006), albeit a very minimal source of microplastics (0.03% as estimated by Cai et al [2021]). In a fate modeling exercise, these authors predicted the European average concentration of fragrance encapsulate polymeric shells in sludge‐treated soil to be 210 µg/kg.…”