Effects of Temperature and Salinity on Perfluorooctane Sulfonate (PFOS) Toxicity in Larval Estuarine Organisms

Abstract

Perfluorooctane sulfonate (PFOS) is a persistent contaminant that has been found globally within the environment. Key data gaps exist in the toxicity of PFOS to marine organisms, especially estuarine species that are crucial to the food web: fish, shrimp, and mollusks. This study developed toxicity thresholds for larval estuarine species, including grass shrimp (Palaemon pugio), sheepshead minnows (Cyprinodon variegatus), mysids (Americamysis bahia), and Eastern mud snails (Tritia obsoleta). Multiple abiotic stressors (salinity and temperature) were included as variables in testing the toxicity of PFOS. Acute 96 h toxicity testing under standard test conditions of 25 °C and 20 ppt seawater yielded LC50 values of 0.919 mg/L for C. variegatus, 1.375 mg/L for A. bahia, 1.559 mg/L for T. obsoleta, and 2.011 mg/L for P. pugio. The effects of increased temperature (32 °C) and decreased salinity (10 ppt) varied with test species. PFOS toxicity for the sheepshead minnows increased with temperature but was not altered by decreased salinity. For grass shrimp and mud snails, PFOS toxicity was greater under lower salinity. The combination of higher temperature and lower salinity was observed to lower the toxicity thresholds for all species. These data demonstrate that expanding toxicity testing to include a wider range of parameters will improve the environmental risk assessment of chemical contaminants, especially for species inhabiting dynamic estuarine ecosystems.

Closing the Gaps in Understanding PFAS Toxicology and Metabolism

“…Models other than human and rodent also were tested, and the results are reported in this Special Issue. These included C. variegatus (sheepshead minnow) [ 17 ], D. rerio (zebrafish) [ 26 , 27 ], and C. elegans (nematode) [ 28 ] and other aquatic species [ 29 ]. Studies with the nematode, C. elegans , observed that PFAS are obesogenic, neurotoxic, immunotoxic, and cause developmental delays [ 28 ], all of which are commonly evaluated toxic endpoints in multiple studies with fish, mice, and human in vitro models and epidemiology studies.…”

“…Few of these chemicals have been tested in mammalian studies; further studies on PFOSA and N-MeFOSA in particular may be warranted [ 26 ]. Lastly, Chung et al [ 29 ] evaluated the effects of temperature and salinity on the toxicity of PFOS in multiple marine or estuarine species, such as C. variegatus (sheepshead minnow), T. obsoleta (Eastern mud snails), P. pugio (grass shrimp), and A. bahia (mysids). Higher temperatures greatly increased toxicity in the sheepshead minnow, with other species showing less sensitivity.…”

“…Higher salinity greatly decreased toxicity in the Eastern mud snail, but less so in other species. This work demonstrates that changing environmental factors are likely to affect PFAS toxicity with differences across species [ 29 ]. These environmental effects may need to be considered within estuarine ecosystems.…”

“…New approach methods (NAMs) can quickly evaluate toxicity for large numbers of PFAS or gather high throughput data to enable more timely risk assessment. Examples include in vitro toxicokinetics studies for large numbers of PFAS [ 12 , 15 ] and across species [ 13 ], in vivo studies coupled with high throughput TK and/or omics methods [ 14 , 17 , 18 , 19 , 22 , 24 ], and toxicity evaluations that utilize fish or invertebrate embryos and larvae as models [ 17 , 26 , 27 , 29 ]. These assays can generate data on biological interactions of multiple PFAS in less time than is typically needed for traditional in vivo exposure studies.…”

“…PFAS are often detected as mixtures in water, soils, foods, food packaging, clothing, and a variety of consumer products, leading to human exposure via multiple pathways [ 30 , 31 ]. This distribution highlights the need to characterize combinations of PFAS together [ 17 , 18 , 19 , 29 ]. Many NAMs currently focus on individual chemicals for each assay, but assays to test mixtures could yield greater understanding of real-world exposures.…”

Closing the Gaps in Understanding PFAS Toxicology and Metabolism

“…Models other than human and rodent also were tested, and the results are reported in this Special Issue. These included C. variegatus (sheepshead minnow) [ 17 ], D. rerio (zebrafish) [ 26 , 27 ], and C. elegans (nematode) [ 28 ] and other aquatic species [ 29 ]. Studies with the nematode, C. elegans , observed that PFAS are obesogenic, neurotoxic, immunotoxic, and cause developmental delays [ 28 ], all of which are commonly evaluated toxic endpoints in multiple studies with fish, mice, and human in vitro models and epidemiology studies.…”

“…Few of these chemicals have been tested in mammalian studies; further studies on PFOSA and N-MeFOSA in particular may be warranted [ 26 ]. Lastly, Chung et al [ 29 ] evaluated the effects of temperature and salinity on the toxicity of PFOS in multiple marine or estuarine species, such as C. variegatus (sheepshead minnow), T. obsoleta (Eastern mud snails), P. pugio (grass shrimp), and A. bahia (mysids). Higher temperatures greatly increased toxicity in the sheepshead minnow, with other species showing less sensitivity.…”

“…Higher salinity greatly decreased toxicity in the Eastern mud snail, but less so in other species. This work demonstrates that changing environmental factors are likely to affect PFAS toxicity with differences across species [ 29 ]. These environmental effects may need to be considered within estuarine ecosystems.…”

“…New approach methods (NAMs) can quickly evaluate toxicity for large numbers of PFAS or gather high throughput data to enable more timely risk assessment. Examples include in vitro toxicokinetics studies for large numbers of PFAS [ 12 , 15 ] and across species [ 13 ], in vivo studies coupled with high throughput TK and/or omics methods [ 14 , 17 , 18 , 19 , 22 , 24 ], and toxicity evaluations that utilize fish or invertebrate embryos and larvae as models [ 17 , 26 , 27 , 29 ]. These assays can generate data on biological interactions of multiple PFAS in less time than is typically needed for traditional in vivo exposure studies.…”

“…PFAS are often detected as mixtures in water, soils, foods, food packaging, clothing, and a variety of consumer products, leading to human exposure via multiple pathways [ 30 , 31 ]. This distribution highlights the need to characterize combinations of PFAS together [ 17 , 18 , 19 , 29 ]. Many NAMs currently focus on individual chemicals for each assay, but assays to test mixtures could yield greater understanding of real-world exposures.…”

Closing the Gaps in Understanding PFAS Toxicology and Metabolism

“…Models other than human and rodent also were tested, and the results are reported in this Special Issue. These included C. variegatus (sheepshead minnow) [ 17 ], D. rerio (zebrafish) [ 26 , 27 ], and C. elegans (nematode) [ 28 ] and other aquatic species [ 29 ]. Studies with the nematode, C. elegans , observed that PFAS are obesogenic, neurotoxic, immunotoxic, and cause developmental delays [ 28 ], all of which are commonly evaluated toxic endpoints in multiple studies with fish, mice, and human in vitro models and epidemiology studies.…”

“…Few of these chemicals have been tested in mammalian studies; further studies on PFOSA and N-MeFOSA in particular may be warranted [ 26 ]. Lastly, Chung et al [ 29 ] evaluated the effects of temperature and salinity on the toxicity of PFOS in multiple marine or estuarine species, such as C. variegatus (sheepshead minnow), T. obsoleta (Eastern mud snails), P. pugio (grass shrimp), and A. bahia (mysids). Higher temperatures greatly increased toxicity in the sheepshead minnow, with other species showing less sensitivity.…”

“…Higher salinity greatly decreased toxicity in the Eastern mud snail, but less so in other species. This work demonstrates that changing environmental factors are likely to affect PFAS toxicity with differences across species [ 29 ]. These environmental effects may need to be considered within estuarine ecosystems.…”

“…New approach methods (NAMs) can quickly evaluate toxicity for large numbers of PFAS or gather high throughput data to enable more timely risk assessment. Examples include in vitro toxicokinetics studies for large numbers of PFAS [ 12 , 15 ] and across species [ 13 ], in vivo studies coupled with high throughput TK and/or omics methods [ 14 , 17 , 18 , 19 , 22 , 24 ], and toxicity evaluations that utilize fish or invertebrate embryos and larvae as models [ 17 , 26 , 27 , 29 ]. These assays can generate data on biological interactions of multiple PFAS in less time than is typically needed for traditional in vivo exposure studies.…”

“…PFAS are often detected as mixtures in water, soils, foods, food packaging, clothing, and a variety of consumer products, leading to human exposure via multiple pathways [ 30 , 31 ]. This distribution highlights the need to characterize combinations of PFAS together [ 17 , 18 , 19 , 29 ]. Many NAMs currently focus on individual chemicals for each assay, but assays to test mixtures could yield greater understanding of real-world exposures.…”

Closing the Gaps in Understanding PFAS Toxicology and Metabolism

“…Models other than human and rodent also were tested, and the results are reported in this Special Issue. These included C. variegatus (sheepshead minnow) [ 17 ], D. rerio (zebrafish) [ 26 , 27 ], and C. elegans (nematode) [ 28 ] and other aquatic species [ 29 ]. Studies with the nematode, C. elegans , observed that PFAS are obesogenic, neurotoxic, immunotoxic, and cause developmental delays [ 28 ], all of which are commonly evaluated toxic endpoints in multiple studies with fish, mice, and human in vitro models and epidemiology studies.…”

“…Few of these chemicals have been tested in mammalian studies; further studies on PFOSA and N-MeFOSA in particular may be warranted [ 26 ]. Lastly, Chung et al [ 29 ] evaluated the effects of temperature and salinity on the toxicity of PFOS in multiple marine or estuarine species, such as C. variegatus (sheepshead minnow), T. obsoleta (Eastern mud snails), P. pugio (grass shrimp), and A. bahia (mysids). Higher temperatures greatly increased toxicity in the sheepshead minnow, with other species showing less sensitivity.…”

“…Higher salinity greatly decreased toxicity in the Eastern mud snail, but less so in other species. This work demonstrates that changing environmental factors are likely to affect PFAS toxicity with differences across species [ 29 ]. These environmental effects may need to be considered within estuarine ecosystems.…”

“…New approach methods (NAMs) can quickly evaluate toxicity for large numbers of PFAS or gather high throughput data to enable more timely risk assessment. Examples include in vitro toxicokinetics studies for large numbers of PFAS [ 12 , 15 ] and across species [ 13 ], in vivo studies coupled with high throughput TK and/or omics methods [ 14 , 17 , 18 , 19 , 22 , 24 ], and toxicity evaluations that utilize fish or invertebrate embryos and larvae as models [ 17 , 26 , 27 , 29 ]. These assays can generate data on biological interactions of multiple PFAS in less time than is typically needed for traditional in vivo exposure studies.…”

“…PFAS are often detected as mixtures in water, soils, foods, food packaging, clothing, and a variety of consumer products, leading to human exposure via multiple pathways [ 30 , 31 ]. This distribution highlights the need to characterize combinations of PFAS together [ 17 , 18 , 19 , 29 ]. Many NAMs currently focus on individual chemicals for each assay, but assays to test mixtures could yield greater understanding of real-world exposures.…”