ABSTRACT
The acute toxicity of diazinon in combination with atrazine concentrations of 5, 10, 20, and 40 microg/L was evaluated using Ceriodaphnia dubia. Atrazine concentrations as low as 5 microg/L in combination with diazinon significantly increased toxicity to C. dubia compared to diazinon alone. Atrazine and diazinon residues within water samples collected from 65 subbasins throughout Denton, Texas, USA were used to assess the environmental relevance of pesticide concentrations. A geographical information system was used to examine the relationship between subbasin land uses and pesticide concentrations. Significant correlations were observed between in situ atrazine and diazinon concentrations and some subbasin land uses. Atrazine was significantly (P < 0.05) correlated to diazinon during some months. Of the 276 samples collected, 39% exceeded our experimentally derived diazinon LC(50) value, and 39% exceeded our minimum atrazine concentration of 5.0 microg/L. Results indicate the potential for increased toxicity from mixtures of compounds at environmentally realistic concentrations.
Subject(s)
Atrazine/toxicity , Cladocera , Diazinon/toxicity , Geographic Information Systems , Herbicides/toxicity , Insecticides/toxicity , Water Pollutants, Chemical/toxicity , Animals , Atrazine/chemistry , Diazinon/chemistry , Drug Interactions , Environment , Herbicides/chemistry , Insecticides/chemistry , Lethal Dose 50ABSTRACT
Continuous electronic fetal monitoring (EFM) in labor is one of the most commonly used interventions during intrapartum care. However, randomized controlled trials, observational studies, and meta-analyses about the use of continuous EFM on low-risk intrapartum patients have found no significant differences in infant outcomes between infants whose mothers had EFM or intermittent auscultation (IA) of the fetal heart rate. In addition, research shows a higher incidence of cesarean birth when EFM is used. Although evidence-based practice is supposed to be our goal, the evidence about the lack of efficacy of EFM has not been used in practice. In fact, EFM has become the standard of practice in this country. Considering these facts, should EFM continue to be the standard of practice for low-risk laboring women? Is informed consent indicated, giving women the choice between EFM and IA? Should IA be offered to all low-risk laboring women? Ethical decision-making models are used to examine those questions and to help nurses better delineate their advocacy role.
Subject(s)
Choice Behavior , Fetal Monitoring/ethics , Fetal Monitoring/psychology , Informed Consent/ethics , Informed Consent/psychology , Patient Participation/psychology , Auscultation , Decision Support Techniques , Evidence-Based Medicine , Female , Fetal Monitoring/nursing , Fetal Monitoring/standards , Humans , Models, Nursing , Nurse's Role , Obstetric Nursing/ethics , Obstetric Nursing/standards , Patient Advocacy/ethics , Patient Selection , Practice Guidelines as Topic , Pregnancy , Pregnancy Outcome , Principle-Based Ethics , VirtuesABSTRACT
Diazinon and copper are two contaminants that are widely found in urban streams and in municipal wastewater effluents. Because these contaminants may be found concurrently, the potential for their joint toxicity is of interest, particularly with regard to toxicity testing of wastewater effluents and the ecological implications of simultaneous exposures in urban streams. Although interactions between metals are well studied, relatively little is known about interactions between metals and organophosphate compounds such as diazinon. In this study, the interaction between copper and diazinon was evaluated using cladoceran (Ceriodaphnia dubia) in 48-h static tests within laboratory water. Using toxic units derived from concurrently established 48-h median lethal concentration values (LC50) of test organisms of each individual toxicant, the effects of the mixture of copper and diazinon on the survival of C. dubia were shown to be generally nonconcentration additive (LC50 significantly greater than one toxic unit). However, evaluation of the dose-response relationship across the entire range of effect levels revealed that the mortality induced by the mixture of copper and diazinon supported concentration additivity at higher effect levels.
