Use of Nonlinear Regression Techniques for Describing Concentration-Response Relationships of Plant Species Exposed to Contaminated Site Soils

Stephenson, Gerald R.; Koper, Nicola; Atkinson, G.; Solomon, Keith R.; Scroggins, Richard P.

doi:10.1897/1551-5028(2000)019<2968:uonrtf>2.0.co;2

Cited by 30 publications

(35 citation statements)

References 8 publications

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“…Data were evaluated using linear and nonlinear regression techniques to generate lethal and effect concentrations (LCx and ECx) resulting in 10, 25, and 50% differences in measured endpoints from control treatments (31). LCx and ECx values were calculated using actual measured concentrations.…”

Section: Methodsmentioning

confidence: 99%

Fluorotelomer Acids are More Toxic than Perfluorinated Acids

Phillips

Dinglasan-Panlilio

Mabury

et al. 2007

Environ. Sci. Technol.

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113

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Saturated and unsaturated fluorotelomer carboxylic acids have been identified as intermediates in the degradation of fluorotelomer alcohols to perfluorinated carboxylic acids (PFCAs). Although surface waters are the likely environmental sink for telomer acids, no fate or toxicity data exist for this matrix. We assessed the acute toxicity of the 4:2, 6:2, 8:2, and 10:2 saturated (FTCA) and unsaturated (FTUCA) fluorotelomer carboxylic acids to Daphnia magna, Chironomus tentans, and Lemna gibba. In general, toxicity increased with increasing fluorocarbon (FC) chain length, particularly for telomer acids of g8 FCs. In addition, the FTCAs were generally more toxic than the corresponding FTUCAs. Acute EC50s ranged from 0.025 mg/L (0.04 µmol/L) for D. magna (10:2 FTCA, immobility) to 63 mg/L (167 µmol/L) for C. tentans (6:2 FTCA, growth). While chain-length trends observed in the current study agree with those previously reported for PFCAs, the toxicity thresholds generated here are up to 10 000 times smaller. Our data provide the first evidence that PFCA precursors are more toxic than the PFCAs themselves.

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Section: Methodsmentioning

confidence: 99%

Fluorotelomer Acids are More Toxic than Perfluorinated Acids

Phillips

Dinglasan-Panlilio

Mabury

et al. 2007

Environ. Sci. Technol.

Self Cite

113

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“…Four replicates of 10 individuals were prepared for each treatment. Survivorship was assessed after 2, 4,6,8,12,16,20,24,36, and 48 h. Water quality parameters were collected at test initiation and completion for all experiments.…”

Section: Pimephales Promelas Bioassaysmentioning

confidence: 99%

“…Effect concentration values (EC10, EC25, EC50) for chronic experiments were obtained using a reparameterized logistic three-parameter model in Sigma Plot (Systat Software) according to Brain et al [23] based on Stephenson et al [24].…”

Section: Statistical Analysesmentioning

confidence: 99%

Aquatic toxicity of sertraline to Pimephales promelas at environmentally relevant surface water pH

Valenti

Perez‐Hurtado

Chambliss

et al. 2009

Enviro Toxic and Chemistry

132

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Abstract-Researchers recognize that ionization state may influence the biological activity of weak acids and bases. Dissociation in aqueous solutions is controlled by the pK a of a compound and the pH of the matrix. Because many pharmaceuticals are implicitly designed as ionizable compounds, site-specific variability in pH of receiving waters may introduce uncertainty to ecological risk assessments. The present study employed 48-h and 7-d toxicity tests with Pimephales promelas exposed to the model weak base pharmaceutical sertraline over a gradient of environmentally relevant surface water pHs. The 48-h experiments were completed in triplicate, and the average lethal concentration values were 647, 205, and 72 mg/L sertraline at pH 6.5, 7.5, and 8.5, respectively. Survivorship, growth, and feeding rate (a nontraditional endpoint linked by other researchers to sertraline's specific mode of action) were monitored during the 7-d experiment. Adverse effects were more pronounced when individuals were exposed to sertraline at pH 8.5 compared to pH 7.5 and 6.5. The pH-dependent toxicological relationships from these studies were related to in-stream pH data for two streams in the Brazos River basin of central Texas, USA. This predictive approach was taken because of the scarcity of environmental analytical data for sertraline. The results of this study emphasized temporal variability associated with in-stream pH linked to seasonal differences within and between these spatially related systems. Relating site-specific pH variability of surface waters to ionization state may allow researchers to reduce uncertainty during ecological risk assessment of pharmaceuticals by improving estimates of biological effects associated with exposure.

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“…Seedling emergence values and the respective SFM and SDM data were analyzed independently for each species using nonlinear or linear regression models as described in Stephenson et al (2000) and Kuperman et al (2003). Histograms of the residuals and stem-andleaf graphs were examined to ensure that normality assumptions were met.…”

Section: Resultsmentioning

confidence: 99%

Toxicities of TNT and RDX to Terrestrial Plants in Five Soils with Contrasting Characteristics

Simini¹,

Checkai²,

Phillips³

et al. 2013

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)XX-07-2013 REPORT TYPE AUTHOR(S)Simini, Michael; Checkai, Ronald T.; Kuperman, Roman G.; Phillips, Carlton T.; Kolakowski, Jan E.; and Kurnas, Carl W. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)Director, ECBC, ATTN: RDCB-DRT-E, APG, MD 21010-5424 PERFORMING ORGANIZATION REPORT NUMBER ECBC-TR-1091 SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)Strategic Environmental Research and Development Program 4800 Mark Center Drive, Suite 17D08, Alexandria, VA 22350-3605 SPONSOR/MONITOR'S ACRONYM(S) SERDP SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTES ABSTRACT-LIMIT 200 WORDSThis study was designed to produce scientifically defensible benchmark data for the development of ecological-based soil screening levels for 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) for terrestrial plants. The physical and chemical properties of different soils may alter the bioavailability and toxicity of TNT and RDX to plant species. We investigated individual ecotoxicities of TNT and RDX to alfalfa (Medicago sativa L.), Japanese millet (J. millet; Echinochloa crus-galli L. [Beauv.]), and perennial ryegrass (Lolium perenne L.) in five natural soils that varied in pH, organic matter, and clay contents. On the basis of EC 50 values (the TNT or RDX concentrations that produce 50% reductions in selected measurement endpoints) and 95% confidence intervals for shoot fresh and dry masses (SDM), TNT weathered-and-aged (W-A) in soils significantly reduced (p < 0.05) growth of alfalfa, J. millet, and perennial ryegrass. RDX W-A in soil was moderately inhibitory to growth of J. millet and perennial ryegrass in all five soils but did not affect growth of alfalfa. No statistically significant correlations between TNT toxicity and these soil properties were identified; however, statistically significant (p < 0.05) inverse relationships were identified between the RDX EC 50 values for perennial ryegrass SDM and soil clay content and pH.

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Use of Nonlinear Regression Techniques for Describing Concentration-Response Relationships of Plant Species Exposed to Contaminated Site Soils

Cited by 30 publications

References 8 publications

Fluorotelomer Acids are More Toxic than Perfluorinated Acids

Fluorotelomer Acids are More Toxic than Perfluorinated Acids

Aquatic toxicity of sertraline to Pimephales promelas at environmentally relevant surface water pH

Toxicities of TNT and RDX to Terrestrial Plants in Five Soils with Contrasting Characteristics

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