Dietary Bioaccumulation and Biotransformation of Hydrophobic Organic Sunscreen Agents in Rainbow Trout

Abstract

The present study investigated the dietary bioaccumulation and biotransformation of hydrophobic organic sunscreen agents, 2‐ethylhexyl‐4‐methoxycinnamate (EHMC) and octocrylene (OCT), in rainbow trout using a modified Organisation for Economic Co‐operation and Development 305 dietary bioaccumulation test that incorporated nonbiotransformed reference chemicals. Trout were exposed to 3 dietary concentrations of each chemical to investigate the relationship between dietary exposure concentration and observed accumulation and depuration. Both EHMC and OCT were significantly biotransformed, resulting in mean in vivo whole‐body biotransformation rate constants (kMET) of 0.54 ± 0.06 and 0.09 ± 0.01 d–1, respectively. The kMET values generated for both chemicals did not differ between dietary exposure concentrations, indicating that chemical concentrations in the fish were not high enough to saturate biotransformation enzymes. Both somatic and luminal biotransformation substantially reduce EHMC and OCT bioaccumulation potential in trout. Biomagnification factors (BMFs) and bioconcentration factors (BCFs) of EHMC averaged 0.0035 kg lipid kg lipid–1 and 396 L kg–1, respectively, whereas those of OCT averaged 0.0084 kg lipid kg lipid–1 and 1267 L kg–1. These values are 1 to 2 orders of magnitude lower than the BMFs and BCFs generated for reference chemicals of similar log KOW. In addition, for both chemicals, derived BMFs and BCFs fell below established bioaccumulation criteria (1.0 kg lipid kg lipid–1 and 2000 L kg–1, respectively), suggesting that EHMC ad OCT are unlikely to bioaccumulate to a high degree in aquatic biota. Environ Toxicol Chem 2020;39:574–586. © 2019 SETAC

Sunscreens: UV filters to protect us: Part 2-Increasing awareness of UV filters and their potential toxicities to us and our environment

“…In Norway, cod liver specimens contained organic UV filters, most notably octocrylene (found in 80% of specimens) and BP-3 (found in 50% of specimens). In Spain, similar UV filters were found in fish species including: white fish, rainbow trout, barb, perch, chub, and mussels ( Blitz and Norton, 2008 , Schneider and Lim, 2019a , Schneider and Lim, 2019b , Narla and Lim, 2020 , Saunders et al, 2020 ). Similar findings have also been seen in aquatic biota in the Pearl River Estuarine of the South China Sea ( Peng et al, 2017 ).…”

“…Bioaccumulation in human adipose tissue has been well documented with freshwater fish consumption in areas including the Great Lakes with mercury, DDT, polychlorinated biphenyls (PCBs) (EPA-US) 2017 ). Organic UVFs have been shown to follow similar metabolic pathways, thus when people eat those fish, the lipophilic compounds are further concentrated in human adipose tissue ( Balmer et al, 2005 , Langford et al, 2015 , Saunders et al, 2020 ).…”

In vitro-in vivo extrapolation of hepatic and gastrointestinal biotransformation rates of hydrophobic chemicals in rainbow trout

“…Empirical in vivo biotransformation rate constants (k MET ; Table 2) for EHMC and OCT were reported previously in a single study performed with rainbow trout following exposure to either chemical at three different dietary concentrations (Saunders et al, 2020). No dosedependent effects on k MET , fish weight, or lipid content was observed.…”

“…No dosedependent effects on k MET , fish weight, or lipid content was observed. Therefore, in the extrapolation of EHMC and OCT biotransformation rates, modeled fish weights and fractional lipid contents were set to the mean of the three reported values (Table 2; Saunders et al, 2020). Empirical k MET values for BAP and PYR in trout were obtained from multiple studies that used different sized trout (Niimi and Palazzo, 1986;Lo et al, 2015b;DiMauro, 2018).…”

Trophic contamination by octocrylene does not affect aerobic metabolic scope in juveniles clownfish

“…The widespread occurrence of OC in the environment has led to its frequent detection in biota. Due to its lipophilic properties and stability, OC tend to accumulate in aquatic organism [5,10,[13][14][15][16][17][18]. The wide distribution of OC is all the more disturbing since it has recently been shown that it could be transformed and accumulated in forms that are more diffi cult to detect and quantify [19].…”