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Saunders LJ, Wania F. Cross-Species Evaluation of Bioaccumulation Thresholds for Air-Breathing Animals. Environ Sci Technol 2023. [PMID: 37450684 DOI: 10.1021/acs.est.2c09115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
In air-breathing organisms, an organic chemical's susceptibility to elimination via urinary excretion and respiratory exhalation can be judged on the basis of the octanol-water partition ratio (KOW) and the octanol-air partition ratio (KOA), respectively. Current regulations specify that chemicals with KOW values of <102 and KOA values of <105 may be screened as non-bioaccumulative in air breathers. Here we used a model-based approach to evaluate whether these thresholds are consistent with a biomagnification factor of 1 for 141 different mammals, birds, and reptiles. Animals with lower rates of respiration (e.g., manatees and sloths) and those ingesting high-lipid diets (e.g., polar bears and carnivorous birds) were predicted to be able to biomagnify persistent chemicals with KOA values of <105. This was also observed for several temperate reptiles due to their lower respiration rates and internal temperatures. Protective KOA thresholds were determined to be <104.85 for mammals, <104.60 for birds, <104.60 for reptiles at >25 °C, and <103.95 for reptiles at ≤25 °C. For all animals, urination alone was not efficient to prevent the biomagnification of any organic chemical. For chemicals with KOW values of <101, we found that biomagnification of persistent chemicals was constrained by the water-air partition ratio (KWA) rather than KOA. Differences in physiology may need to be considered in bioaccumulation assessments of air-breathing species.
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Affiliation(s)
- Leslie J Saunders
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Frank Wania
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
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Stoyanovich SS, Saunders LJ, Yang Z, Hanson ML, Hollebone BP, Orihel DM, Palace V, Rodriguez-Gil JL, Mirnaghi FS, Shah K, Blais JM. Chemical Weathering Patterns of Diluted Bitumen Spilled into Freshwater Limnocorrals. Environ Sci Technol 2023. [PMID: 37267462 DOI: 10.1021/acs.est.2c05468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Due to the sudden nature of oil spills, few controlled studies have documented how oil weathers immediately following accidental release into a natural lake environment. Here, we evaluated the weathering patterns of Cold Lake Winter Blend, a diluted bitumen (dilbit) product, by performing a series of controlled spills into limnocorrals installed in a freshwater lake in Northern Ontario, Canada. Using a regression-based design, we added seven different dilbit volumes, ranging from 1.5 to 180 L, resulting in oil-to-water ratios between 1:71,000 (v/v) and 1:500 (v/v). We monitored changes in the composition of various petroleum hydrocarbons (PHCs), including n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and oil biomarkers in dilbit over time, as it naturally weathered for 70 days. Depletion rate constants (kD) of n-alkanes and PAHs ranged from 0.0009 to 0.41 d-1 and 0.0008 to 0.38 d-1, respectively. There was no significant relationship between kD and spill volume, suggesting that spill size did not influence the depletion of petroleum hydrocarbons from the slick. Diagnostic ratios calculated from concentrations of n-alkanes, isoprenoids, and PAHs indicated that evaporation and photooxidation were major processes contributing to dilbit weathering, whereas dissolution and biodegradation were less important. These results demonstrate the usefulness of large scale field studies carried out under realistic environmental conditions to elucidate the role of different weathering processes following a dilbit spill.
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Affiliation(s)
| | | | - Zeyu Yang
- Emergencies Science and Technology Section, Environment and Climate Change Canada, Ottawa, Ontario K1V 1C7, Canada
| | - Mark L Hanson
- Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Bruce P Hollebone
- Emergencies Science and Technology Section, Environment and Climate Change Canada, Ottawa, Ontario K1V 1C7, Canada
| | - Diane M Orihel
- Department of Biology and School of Environmental Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Vince Palace
- International Institute for Sustainable Development, Experimental Lakes Area, 111 Lombard Avenue, Suite 325, Winnipeg, Manitoba R3N 0T4, Canada
| | - Jose L Rodriguez-Gil
- Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- International Institute for Sustainable Development, Experimental Lakes Area, 111 Lombard Avenue, Suite 325, Winnipeg, Manitoba R3N 0T4, Canada
| | - Fatemeh S Mirnaghi
- Emergencies Science and Technology Section, Environment and Climate Change Canada, Ottawa, Ontario K1V 1C7, Canada
| | - Keval Shah
- Emergencies Science and Technology Section, Environment and Climate Change Canada, Ottawa, Ontario K1V 1C7, Canada
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Saunders LJ, Nichols JW, Arnot JA, Armitage JM, Wania F. An amended in vitro- in vivo extrapolation model that accounts for first pass clearance effects on chemical bioaccumulation in fish. Environ Sci Process Impacts 2023; 25:741-754. [PMID: 36876637 DOI: 10.1039/d2em00522k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Measured rates of in vitro intrinsic clearance for fish may be extrapolated to the whole animal as a means of estimating a whole-body biotransformation rate constant (kB; d-1). This estimate of kB can then be used as an input to existing bioaccumulation prediction models. Most in vitro-in vivo extrapolation/bioaccumulation (IVIVE/B) modeling efforts to date have focused on predicting the chemical bioconcentration in fish (aqueous only exposure), with less attention paid to dietary exposures. Following dietary uptake, biotransformation in the gut lumen, intestinal epithelia, and liver can reduce chemical accumulation; however, current IVIVE/B models do not consider these first pass clearance effects on dietary uptake. Here we present an amended IVIVE/B model that accounts for first pass clearance. The model is then used to examine how biotransformation in the liver and intestinal epithelia (alone or combined) may impact chemical accumulation that occurs during dietary exposure. First pass clearance by the liver can greatly reduce dietary uptake of contaminants, but these effects are only apparent at rapid rates of in vitro biotransformation (first order depletion rate constant kDEP ≥ 10 h-1). The impact of first pass clearance becomes more pronounced when biotransformation in the intestinal epithelia is included in the model. Modelled results suggest that biotransformation in the liver and intestinal epithelia cannot entirely explain reduced dietary uptake reported in several in vivo bioaccumulation tests. This unexplained reduction in dietary uptake is attributed to chemical degradation in the gut lumen. These findings underscore the need for research to directly investigate luminal biotransformation in fish.
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Affiliation(s)
- Leslie J Saunders
- Department of Physical and Environmental Science, University of Toronto Scarborough, Toronto, Ontario, Canada.
| | - John W Nichols
- United States Environmental Protection Agency, Duluth, MN, USA
| | - Jon A Arnot
- Department of Physical and Environmental Science, University of Toronto Scarborough, Toronto, Ontario, Canada.
- ARC Arnot Research and Consulting, Toronto, Ontario, Canada
| | - James M Armitage
- AES Armitage Environmental Sciences Inc., Ottawa, Ontario, Canada
| | - Frank Wania
- Department of Physical and Environmental Science, University of Toronto Scarborough, Toronto, Ontario, Canada.
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Saunders LJ, Nichols JW. Models Used to Predict Chemical Bioaccumulation in Fish from in Vitro Biotransformation Rates Require Accurate Estimates of Blood-Water Partitioning and Chemical Volume of Distribution. Environ Toxicol Chem 2023; 42:33-45. [PMID: 36282023 PMCID: PMC10824487 DOI: 10.1002/etc.5503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/11/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
Methods for extrapolating measured in vitro intrinsic clearance to a whole-body biotransformation rate constant (kB ) have been developed to support modeled bioaccumulation assessments for fish. The inclusion of extrapolated kB values into existing bioaccumulation models improves the prediction of chemical bioconcentration factors (BCFs), but there remains a tendency for these methods to overestimate BCFs relative to measured values. Therefore, a need exists to evaluate the extrapolation procedure to assess potential sources of error in predicted kB values. We examined how three different approaches (empirically based, composition based, and polyparameter linear free energy relationships [ppLFERs]) used to predict chemical partitioning in vitro (liver S9 system; KS9W ), in blood (KBW ), and in whole fish tissues (KFW ) impact the prediction of a chemical's hepatic clearance binding term (fU ) and apparent volume of distribution (VD ), both of which factor into the calculation of kB and the BCF. Each approach yielded different KS9W , KBW , and KFW values, but resulted in fU values that were of similar magnitude and remained relatively constant at log octanol-water partition ratios (KOW ) greater than 4. This is because KBW and KS9W values predicted by any given approach exhibit a similar dependence on log KOW (i.e., regression slope), which results in a cancelation of "errors" when fU is calculated. In contrast, differences in KBW values predicted by the three approaches translate to differences in VD , and by extension kB and the BCF, which become most apparent at log KOW greater than 6. There is a need to collect KBW and VD data for hydrophobic chemicals in fish that can be used to evaluate and improve existing partitioning prediction approaches in extrapolation models for fish. Environ Toxicol Chem 2023;42:33-45. © 2022 SETAC.
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Affiliation(s)
- Leslie J. Saunders
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
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Saunders LJ, Rodriguez-Gil JL, Stoyanovich SS, Kimpe LE, Hanson ML, Hollebone BP, Orihel DM, Blais JM. Effect of spilled diluted bitumen on chemical air-water exchange in boreal lake limnocorrals. Chemosphere 2022; 291:132708. [PMID: 34715102 DOI: 10.1016/j.chemosphere.2021.132708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 10/19/2021] [Accepted: 10/24/2021] [Indexed: 06/13/2023]
Abstract
Following spills into water, petroleum oils can spread widely and produce surface slicks. Resulting slicks may impede volatilization and possibly increase chemical persistence in water. While the influence of oil films on chemical air-water exchange has been examined through theoretical and laboratory studies, field studies have not been conducted to assess the relevance of these effects following actual oil spill events. Here we evaluated the effect of diluted bitumen (dilbit) experimentally spilled in limnocorrals installed in a boreal lake on the volatilization of sulfur hexafluoride (SF6), a non-reactive volatile tracer gas. Dilbit spills were monitored over 70 days and SF6 was introduced twice (after 7 and 48 days) to evaluate the influence of spilled dilbit on the loss of SF6 from water. Volatilization rate constants of SF6 (kVOL) significantly decreased by up to 80% with increasing total dilbit spill cover. Using a theoretical equation, decreases in kVOL were largely explained by a reduction in open water area where chemical exchange across the air-water interface occurs. Apparent effects of the slick on SF6 mass transfer were estimated to be smaller by comparison (20%).To account for this reduction in volatilization, oil spill fate models should include a correction to consider the impact of spill cover on the air-water exchange of organic chemicals.
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Affiliation(s)
- Leslie J Saunders
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
| | - Jose L Rodriguez-Gil
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada; International Institute for Sustainable Development Experimental Lakes Area, Winnipeg, Manitoba, Canada; Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada
| | | | - Linda E Kimpe
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Mark L Hanson
- Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Bruce P Hollebone
- Emergencies Science and Technology Section, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Diane M Orihel
- Department of Biology and School of Environmental Studies, Queen's University, Kingston, Ontario, Canada
| | - Jules M Blais
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
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Saunders LJ, Fitzsimmons PN, Nichols JW, Gobas FAPC. In vitro-in vivo extrapolation of hepatic and gastrointestinal biotransformation rates of hydrophobic chemicals in rainbow trout. Aquat Toxicol 2020; 228:105629. [PMID: 33002683 PMCID: PMC7962060 DOI: 10.1016/j.aquatox.2020.105629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 08/24/2020] [Accepted: 09/05/2020] [Indexed: 06/11/2023]
Abstract
Hepatic in vitro biotransformation assays, in combination with in vitro-in vivo extrapolation (IVIVE) and bioaccumulation modeling, can be used to support regulatory bioaccumulation assessments. In most applications, however, these methods ignore the possibility of extrahepatic metabolism. Here we evaluated intestinal biotransformation in rainbow trout using S9 fractions prepared from the upper intestinal (GIT) epithelium. Measured levels of activity determined using standard substrates for phase I and phase II biotransformation enzymes were within 2-fold of activities measured in hepatic S9 fractions. In vitro intrinsic clearance rates for 2-ethylhexyl-4-methoxycinnamate (EHMC; an organic sunscreen agent) and two polycyclic aromatic hydrocarbons (pyrene [PYR] and benzo(a)pyrene [BAP]) were significantly higher in liver S9 fractions than in GIT S9 fractions. For octocrylene (OCT; a second sunscreen agent), however, in vitro intrinsic clearance rates were higher in GIT S9 fractions compared to liver S9 fractions. An existing 'liver only' IVIVE model was expanded to consider biotransformation in both the liver and GIT. Relevant IVIVE scaling factors were developed by morphological, histological, and biochemical evaluation of trout intestines. For chemicals biotransformed at higher rates by hepatic S9 fractions (i.e., BAP, PYR, EHMC), the 'liver & GIT' model yielded whole-body biotransformation rate constants (kMET) that were within 1.2 to 1.4-fold of those estimated using the 'liver only' model. In contrast to these findings, the mean kMET for OCT obtained using the 'liver & GIT' model was 3.3 times higher than the mean kMET derived using the 'liver only' model and was in good agreement with empirical kMET estimates determined previously for trout (<20 % difference). The results of this study suggest that current 'liver only' IVIVE approaches may underestimate in vivo biotransformation rates for chemicals that undergo substantial biotransformation in the GIT.
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Affiliation(s)
- Leslie J Saunders
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | | | - John W Nichols
- United States Environmental Protection Agency, Duluth, MN, USA
| | - Frank A P C Gobas
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada; School of Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia, Canada.
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Saunders LJ, Hoffman AD, Nichols JW, Gobas FA. Dietary Bioaccumulation and Biotransformation of Hydrophobic Organic Sunscreen Agents in Rainbow Trout. Environ Toxicol Chem 2020; 39:574-586. [PMID: 31749247 PMCID: PMC7424631 DOI: 10.1002/etc.4638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/13/2019] [Accepted: 11/18/2019] [Indexed: 05/10/2023]
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.
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Affiliation(s)
- Leslie J. Saunders
- Department of Biological Sciences, Simon Fraser University,
Burnaby, British Columbia, Canada
| | - Alex D. Hoffman
- United States Environmental Protection Agency, Duluth,
Minnesota, USA
| | - John W. Nichols
- United States Environmental Protection Agency, Duluth,
Minnesota, USA
| | - Frank A.P.C. Gobas
- Department of Biological Sciences, Simon Fraser University,
Burnaby, British Columbia, Canada
- School of Resource and Environmental Management, Simon
Fraser University, Burnaby, British Columbia, Canada
- Address correspondence to
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Saunders LJ, Fontanay S, Nichols JW, Gobas FA. Concentration dependence of in vitro biotransformation rates of hydrophobic organic sunscreen agents in rainbow trout S9 fractions: Implications for bioaccumulation assessment. Environ Toxicol Chem 2019; 38:548-560. [PMID: 30569498 PMCID: PMC6477924 DOI: 10.1002/etc.4342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/03/2018] [Accepted: 12/16/2018] [Indexed: 05/04/2023]
Abstract
In vitro biotransformation studies were performed to support the bioaccumulation assessment of 3 hydrophobic organic ultraviolet filters (UVFs), 4-methylbenzylidene camphor (4-MBC), 2-ethylhexyl-4-methoxycinnamate (EHMC), and octocrylene. In vitro depletion rate constants (kdep ) were determined for each UVF using rainbow trout liver S9 fractions. Incubations performed with and without added cofactors showed complete (4-MBC) or partial (EHMC and octocrylene) dependence of kdep on addition of the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH), suggesting that hydrolysis of EHMC and octocrylene by NADPH-independent enzymes (e.g., carboxylesterases) is an important metabolic route. The concentration dependence of kdep was then evaluated to estimate Michaelis-Menten parameters (KM and Vmax ) for each UVF. Measured kdep values were then extrapolated to apparent whole-body biotransformation rate constants using an in vitro-in vivo extrapolation (IVIVE) model. Bioconcentration factors (BCFs) calculated from kdep values measured at concentrations well below KM were closer to empirical BCFs than those calculated from kdep measured at higher test concentrations. Modeled BCFs were sensitive to in vitro binding assumptions employed in the IVIVE model, highlighting the need for further characterization of chemical binding effects on hepatic clearance. The results suggest that the tested UVFs are unlikely to accumulate to levels exceeding the European Union Registration, Evaluation, Authorisation, and Restriction regulation criterion for bioaccumulative substances (BCF > 2000 L kg-1 ). However, consideration of appropriate in vitro test concentrations and binding correction factors are important when IVIVE methods are used to refine modeled BCFs. Environ Toxicol Chem 2019;38:548-560. © 2018 SETAC.
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Affiliation(s)
- Leslie J. Saunders
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Simon Fontanay
- Department of Biological Engineering, Polytech Clermont-Ferrand, France
| | - John W. Nichols
- United States Environmental Protection Agency, Duluth, Minnesota, USA
| | - Frank A.P.C. Gobas
- School of Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia, Canada
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Gobas FAPC, Lee YS, Saunders LJ, Moore MM, Trowell JJ, Kennedy CJ. Response to Comment on: "Estimating the Bioconcentration Factors of Hydrophobic Organic Chemicals from Biotransformation Rates Using Rainbow Trout Hepatocytes". Arch Environ Contam Toxicol 2019; 76:154-156. [PMID: 30413865 DOI: 10.1007/s00244-018-0579-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
| | - Yung-Shan Lee
- Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
| | | | - Margo M Moore
- Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
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Saunders LJ, Mazumder A, Lowe CJ. Pharmaceutical concentrations in screened municipal wastewaters in Victoria, British Columbia: A comparison with prescription rates and predicted concentrations. Environ Toxicol Chem 2016; 35:919-929. [PMID: 26363402 DOI: 10.1002/etc.3241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 05/28/2015] [Accepted: 09/10/2015] [Indexed: 06/05/2023]
Abstract
Pharmaceuticals and personal care products (PPCPs) are emerging chemicals of concern detected in surface waters globally. Recent reviews advocate that PPCP occurrence, fate, and exposure need to be better predicted and characterized. The use of pharmaceutical prescription rates to estimate PPCP concentrations in the environment has been suggested. Concentrations of 7 pharmaceuticals (acetylsalicylic acid, diclofenac, fenoprofen, gemfibrozil, ibuprofen, ketoprofen, and naproxen) were measured in municipal wastewater using gas chromatography/ion trap-tandem mass spectroscopy (GC/IT-MS/MS). Subregional pharmaceutical prescription data were investigated to determine whether they could predict measured effluent concentrations (MECs) in wastewaters. Predicted effluent concentrations (PECs) for 5 of the 7 pharmaceuticals were within 2-fold agreement of the MECs when the fraction of parent pharmaceutical excreted was not considered. When the fraction of parent pharmaceutical excreted was considered, the respective PECs decreased, and most were within an order of magnitude of the MECs. Regression relationships of monthly PECs versus MECs were statistically significant (p < 0.05) but weak (R(2) = 0.18-0.56) for all pharmaceuticals except ketoprofen. This suggests high variability in the data and may be the result of factors influencing MECs such as the analytical methods used, wastewater sampling frequency, and methodology. The PECs were based solely on prescription rates and did not account for inputs of pharmaceuticals that had a significant over-the-counter component or were from other sources (e.g., hospitals).
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Affiliation(s)
- Leslie J Saunders
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Asit Mazumder
- Water and Aquatic Sciences Research Program, Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Christopher J Lowe
- Water and Aquatic Sciences Research Program, Department of Biology, University of Victoria, Victoria, British Columbia, Canada
- Capital Regional District, Victoria, British Columbia, Canada
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Williams SA, Laney SJ, Bierwert LA, Saunders LJ, Boakye DA, Fischer P, Goodman D, Helmy H, Hoti SL, Vasuki V, Lammie PJ, Plichart C, Ramzy RMR, Ottesen EA. Development and standardization of a rapid, PCR-based method for the detection of Wuchereria bancrofti in mosquitoes, for xenomonitoring the human prevalence of bancroftian filariasis. Ann Trop Med Parasitol 2002; 96 Suppl 2:S41-6. [PMID: 12625916 DOI: 10.1179/000349802125002356] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PCR has recently been studied as a promising tool for monitoring the progress of efforts to eliminate lymphatic filariasis. PCR can be used to test concurrently at least 30 pools, with as many as 40 mosquitoes in each pool, for the presence of filarial larvae. The SspI PCR assay for the detection of Wuchereria bancrofti DNA in pools of mosquitoes has been used since 1994 in a variety of laboratories worldwide. During that time, the original assay has been modified in these different laboratories and no standardized assay currently exists. In an effort to standardize and improve the assay, a meeting was held on 15-16 November 2001, at Emory University in Atlanta, with representatives from most of the laboratories currently using the assay. The first round of testing was designed to test the four most promising methods for DNA extraction from pools of mosquitoes. Two of the four methods stood out as clearly the best and these will be now optimised and evaluated in two further rounds of testing.
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Affiliation(s)
- S A Williams
- Clark Science Center, Smith College, Northampton, MA 01063, USA.
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