Review of Fate, Exposure, and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen Usage and Human Health (2022) / Chapter Skim
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6 Review of Studies on the Effects of UV Filters in Aquatic Environments
6 Review of Studies on the Effects of UV Filters in Aquatic Environments
Pages 121-160
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From page 121... ...
The majority of toxicity data on effects are for direct exposures to UV filters in water or sediment and thus constitute most of what can be found in this chapter. Laboratory toxicity testing data are the most widely used in the effects assessment inputs to ERAs of individual chemicals.
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From page 122... ...
. Acute toxicity tests are shorter in duration (typically 24–96 hours)
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From page 123... ...
. ACUTE TOXICITY QSAR OVERVIEW Determinations of QSARs are commonly employed at the earliest tiers of an ERA.
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From page 124... ...
Sulisobenzone Phenols 462 1160 5580 Y Y Y (polar narcosis) Titanium dioxide (ionoregulatory disruption)
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From page 125... ...
Of these four, meradimate would likely have the highest priority as being the most potentially toxic of the four UV filters that do not currently have acute toxicity data. Several potential modes of action are indicated across all UV filters exemplifying the diversity of substitutions and functionalizations present.
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From page 126... ...
These key considerations are based on existing toxicity testing guidelines used by OECD and EPA. However, many guidelines were not included as considerations in this effort in order to be more inclusive, particularly given the number of toxicity tests conducted on nonstandard toxicity test species that were important to consider.
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From page 127... ...
a"Technically credible" endpoints are ECx- lowest concentration tested is below the ECx, confidence intervals are calculable, replication was > 1, treatments were > 3 and preferably 5 or more concentrations used in a concentration range (2–3x)
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From page 128... ...
Avobenzone Limited aquatic toxicity data is available for avobenzone on standard test organisms. Acute toxicity studies reported in ECHA5 report no effects under solubility (27 µg/L; Table 4.1)
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From page 129... ...
and no chronic toxicity tests were conducted for registration with ECHA. Reported in ECHA are a 72-h NOEC ≥ 8.9 µg/L (the highest mean measured concentration from saturated solutions)
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From page 130... ...
Algal studies present the most variable range of acute toxicity data. The majority of studies report 72- to 96-h EC50s for growth inhibition from 670 to 5,220 µg/L (Du et al., 2017; Esperanza et al., 2019; Lee et al., 2020; Sieratowicz et al., 2011; ECHA)
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From page 131... ...
. Acute toxicity tests have been reported for four intact hard coral species using adult fragments or coral larvae.
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From page 132... ...
subcapitata is reported in ECHA. Three zebrafish acute toxicity tests with octisalate reported no mortality within water solubility in ECHA, reporting LC50 values ranging from > 82,000 µg/L to 613,000 µg/L (nominal)
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From page 133... ...
Therefore, results of toxicity testing on these UV filters can vary significantly, requiring consideration of these influential factors. Most toxicity studies have been conducted on nanoparticle sizes (< 100 nm)
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From page 134... ...
Silane coatings on ZnO nanoparticles create a more hydrophilic particle and greater acute toxicity to the marine copepod, Tigriopus japonicus, that is more due to the size-dependent uptake and therefore zinc exposure rather than ROS generation differences. A study with Escherichia coli found that carboxymethyl cellulose (CMC)
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From page 135... ...
. Acute toxicity to fish is low, ranging from 96-h LC50 155,000 µg/L (medaka; Ma et al., 2012)
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From page 136... ...
. In fact, there are more studies that find no impact up to 10,000 µg/L and above including acute toxicity in mature marine abalone (Haliotis diversicolor supertexta)
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From page 137... ...
Results of acute toxicity tests assessed as potentially ERA-applicable by the committee are plotted in Figure 6.1 (limited to category 1 studies for ease of graphing)
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From page 138... ...
magna acute toxicity data were available. For these UV filters, ECOSAR v.
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From page 139... ...
Insoluble TiO2 is not toxic within the range of solubility and ZnO toxicity is close, but slightly below, the limit of solubility. Chronic toxicity to D
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From page 140... ...
When multiple studies were available, geometric means were calculated to represent the central tendency of the responses. Chronic toxicity data for fish exposed to UV filters is too sparse to allow meaningful analysis.
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From page 141... ...
magna acute toxicity data were compared to data on acute toxicity to corals as a means to ascertain corals' sensitivity to UV filters relative to that of standard freshwater invertebrates. Data for oxybenzone, sulisobenzone, dioxybenzone, octinoxate, and octocrylene were gathered from the literature after evaluation for data quality (i.e., data provided in the tables in Appendix E)
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From page 142... ...
. This concentration is universally FIGURE 6.5 Plot of the ranges of coral acute toxicity data compared to Daphnia magna acute toxicity data.
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From page 143... ...
to be considered a long-term exposure. Standard and nonstandard taxa were utilized whenever possible and SSDs were postulated only when algae, invertebrate, and fish toxicity data were available.
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From page 144... ...
SSDs were of more varying quality than the ones used here and it has not been demonstrated that acute cell line data can be so extrapolated. Octinoxate Based on the acute toxicity values for 11 species, sufficient information was available to develop an SSD for octinoxate, with some caveats.
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From page 145... ...
REVIEW OF STUDIES ON THE EFFECTS OF UV FILTERS IN AQUATIC ENVIRONMENTS 145 FIGURE 6.6 Acute and chronic species sensitivity distributions for oxybenzone, octinoxate, TiO2, and ZnO. NOTE: LCL = lower confidence limit.
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From page 146... ...
One advantage of this chronic data set is that the water hardness has been universally 17 Textwas modified here and elsewhere in the report, after release of the prepublication report, in order to clarify the data source for the species sensitivity distributions for TiO2 and ZnO (acute)
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From page 147... ...
(2015) estimated that based on acute toxicity information the HC5 was 60 µg/L with a 90 percent confidence range of 30–150 µg/L.
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From page 148... ...
. Establishing a consequential endocrine modulation or endocrine disruptive activity that eventually impacts population level responses of growth, reproduction and appropriate sex ratios is largely absent in the suite of studies described here.
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In this section, the committee considers potential exposure of groups of listed species and toxicity information about members of these groups, though the species of study themselves may not be listed. Most of this 20 See https://www.epa.gov/chemical-research/toxicity-forecasting.
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From page 150... ...
Toxicity tests have been conducted on several standard freshwater species for 10 of the UV filters (described in Comparative Potency of UV Filters to Standard Test Organisms) , with several UV filters having measured 96-h LC50s under solubility limits.
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From page 151... ...
No exposure or toxicity data currently exist for ESA listed species although data is available for the marine species M galloprovincialis (Mediterranean mussel)
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From page 152... ...
Ecosystem-level effects can be difficult to assess because experiments and toxicity studies that traditionally use single species cannot simply be summed to predict ecosystem effects due to complex interactions among species. Studies on species interactions and ecosystem processes are frequently lacking in the literature on the effects of chemical contaminants (Richmond et al., 2017)
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From page 153... ...
. Ecosystem Processes Effects on Nutrient Cycling Nutrient transformations that occur in microbial communities can have large effects on ecosystem health, yet little is known about the influence of UV filters on these microbially mediated processes.
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From page 154... ...
Effects on Primary Production Primary production by benthic or water column primary producers provides the base of the aquatic food web in most aquatic ecosystems. Studies are available for algae, typically freshwater algae, for all UV filters other than those with no toxicity information at all.
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From page 155... ...
. Causal Analysis and UV Filters In this section, UV filters are examined in the context of other known stressors by first considering the stressors that are identified by the scientific community as prominent causes of impaired aquatic ecosystems, with consideration of how to assess the degree to which UV filters specifically are a contributing factor.
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From page 156... ...
However, as described in Chapter 4, the spatial and temporal variability and longer-term mean exposure concentrations for UV filters are not well characterized. Possible Cumulative and Interacting Effects The suite of stressors on aquatic ecosystems described above collectively contribute to observed impairments and could include independent effects but also effects involving interactions (additive, synergistic and/or antagonistic)
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From page 157... ...
(2019b) exposed two coral species to dilutions of a "wash-off" of a sunscreen product (containing 7 percent octinoxate, 3.6 percent octocrylene)
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From page 158... ...
Filling knowledge gaps in toxicity data will inform higher tiered risk assessments, including the creation of SSDs when deemed necessary, as well as information about potential effects on threatened and endangered species via data for surrogate species. Importantly, findings about toxicity, when possible, must be put in perspective with environmental exposure in order to ultimately determine risk.
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From page 159... ...
Knowledge Gap: There are very few studies on the toxicity of UV filter degradates, despite observations of degradation of avobenzone, padimate O, octinoxate, and oxybenzone during toxicity tests. Knowledge Gap: There are few studies on community and ecosystem dynamics, the need for which is supported by the few that indicate potential effects on ecosystem processes like nutrient cycling, organic matter decomposition, and effects on primary producers and other key species.
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