Predicting the impact and duration of persistent and mobile organic compounds in groundwater systems using a contaminant mass discharge approach

This study investigated methods for predicting the duration and impact on groundwater quality from persistent and mobile organic compounds (PMOCs) at a drinking water well field affected by multiple contaminant sources. The fungicide metabolite N,N-dimethylsulfamide (DMS), which frequently occurs above the Danish groundwater quality criterion (0.1 μg/L), was used as an example. By combining contaminant mass discharge (CMD) estimations, modeling, and groundwater dating, a number of important discoveries were made. The current center of contaminant mass was located near the source area. The CMD at the well field was predicted to peak in 2040, and an effect from the investigated sources on groundwater quality could be expected until the end of the 21st century. A discrepancy in the current CMD at the well field and the estimated arrival time from the studied source area suggested an additional pesticide source, which has not yet been thoroughly investigated. The presence of the unknown source was supported by model simulations, producing an improved mass balance after inclusion of a contaminant source closer to the well field. The approach applied here was capable of predicting the duration and impact of DMS contamination at a well field at catchment scale. It furthermore shows potential for identification and quantification of the contribution from individual sources, and is also applicable for other PMOCs. Predicting the duration of the release and impact of contaminant sources on abstraction wells is highly valuable for water resources management and authorities responsible for contaminant risk assessment, remediation, and long-term planning at water utilities.

Long-term leaching through clayey till of N,N-dimethylsulfamide, a Persistent and Mobile Organic Compound (PMOC)

Environmental pollution with Persistent and Mobile Organic Compounds (PMOC) from anthropogenic activities is an increasing cause for concern. These compounds are readily leached to groundwater aquifers and are likely to resist degradation, putting pressure on groundwater resources. Pesticides can form PMOCs upon degradation in the environment. The PMOC N,N-dimethylsulfamide (DMS) was the most frequently detected pesticide metabolite in Danish drinking water wells in 2020, although the pesticidal use of the last parent compound (tolylfluanid) ended in 2007. This study aimed to improve the understanding of the leaching of the PMOC DMS from clayey tills by combining a review of compound properties, sources and use, comprehensive field observations and numerical flow and solute transport modeling. The modeling explored the mechanisms of DMS retention during vertical transport in clayey till and the fingerprint in the underlying aquifer. The results were supported by detailed field observations at an agricultural site with strawberry production. Porewater samples were collected from clayey till to a depth of 12 m bgs by a custom designed installation method of suction cups. Groundwater sampling (249 samples) was designed to provide vertical concentration profiles at various distances from the presumed sources. The review of properties showed that the parent compounds and intermediates degrade quickly in topsoil, releasing the highly persistent and mobile DMS. We tested the effect of fractures on transport with different hydraulic apertures and a scenario without fractures by numerical modeling. The results showed that the presence of fractures can smooth the breakthrough curve below the clayey till, leading to faster breakthrough, lower maximum concentration, and several decades of prolonged leaching in simulations with the largest aperture (20 μm). The fracture-matrix interaction is a possible explanation for the observed delay of leaching from clayey till. The vertical concentration profiles in groundwater were used for identifying the sources at the field site and testing source strengths. Assigning one point source (200 μg/L) and two diffuse sources (40-50 μg/L) to the model produced vertical concentration profiles that compared well with observed field data in clayey till and the aquifer. All results were integrated into a conceptual model for the environmental fate of PMOCs in soil and groundwater. The findings of this study imply that the presence of fractures in clayey till should be considered in conceptual site models, since they can substantially prolong the leaching of PMOCs to groundwater. The integration of comprehensive field investigations and numerical modeling is key to understand the fate of PMOCs in complex field systems with different source types. Together with widespread occurrences of PMOCs in groundwater systems, the results highlight the need for improved approval procedures for pesticides and biocides which considers their persistent and mobile metabolites.

Risk assessment of consumer spray products using in vitro lung surfactant function inhibition, exposure modelling and chemical analysis

Consumer spray products release aerosols that can potentially be inhaled and reach the deep parts of the lungs. A thin layer of liquid, containing a mixture of proteins and lipids known as lung surfactant, coats the alveoli. Inhibition of lung surfactant function can lead to acute loss of lung function. We focused on two groups of spray products; 8 cleaning and 13 impregnation products, and in the context of risk assessment, used an in vitro method for assessing inhibition of lung surfactant function. Original spray-cans were used to generate aerosols to measure aerodynamic particle size distribution. We recreated a real-life exposure scenario to estimate the alveolar deposited dose. Most impregnation products inhibited lung surfactant function at the lowest aerosolization rate, whereas only two cleaning products inhibited function at the highest rates. We used inhibitory dose and estimated alveolar deposition to calculate the margin of safety (MoS). The MoS for the inhibitory products was ≤1 for the impregnation products, while much larger for the cleaning products (>880). This risk assessment focused on the risk of lung surfactant function disruption and provides knowledge on an endpoint of lung toxicity that is not investigated by the currently available OECD test guidelines.

P634Motivation for physical activity predicts effect of cardiac rehabilitation in an elderly cardiac population

Background

Motivation for physical activity is a psychological parameter that is sparsely described in secondary prevention, and it is plausible that motivation contributes to differential effect of CR.

Purpose

To investigate if motivation, measured using the behavioural regulation in exercise questionnaire (BREQ-2), predicts VO2peak in elderly cardiac patients before and after CR.

Methods

Prospective cohort study (Danish cohort from the EU-CaRE study) of elderly patients with ischemic or valvular disease enrolled in CR. Motivation for physical activity was measured using the BREQ-2 questionnaire at baseline, which measures five constructs of motivation and a summed score. VO2peak was measured before and after CR by a cardiopulmonary exercise test (CPET). The impact of motivation on VO2peak was examined using standardized multiple regression analyses.

Results

203 patients performed the baseline tests. 182 (90%) completed CR and had full data available. Dropout was not associated with motivation. VO2peak at baseline was 18 ml/kg/min (SD±5.1) and was associated with motivation score: for each SD increase in motivation VO2peak was 1.05 (0.43–1.69) ml/kg/min higher (p<0.01). Mean improvement was 2.3 (12%) ml/kg/min (SD±4.3). Higher motivation was positively associated with VO2peak (0.78 (0.33–1.24) pr. SD improvement (p=0.01) after adjusting for age, sex, depression, comorbidities and baseline VO2peak (Table). Subscales of the BREQ2 indicate that internal but not external motivation drives this positive association.

Predictors of change in VO2peak Age and sex adjusted Multiple adjusted model Motivation (RAI pr. SD) 0.57 (0.12 to 1.01)* 0.78 (0.33 to 1.24)** Baseline VO2peak (pr. SD) −0.56 (−1.16 to 0.21) −1.30 (−1.94 to −0.66)*** Age (pr. SD) −0.84 (−1.85 to 0.18) −1.00 (−2.01 to −0.01)* Sex (male) −0.18 (−1.21 to 0.85) 0.74 (−0.28 to 1.76) Previous smoker −0.23 (−1.22 to 0.77) −0.37 (−1.34 to 0.59) Current smoker −1.43 (−3.00 to 0.14) −1.89 (−3.36 to −0.40)* Diabetes (Yes) −1.37 (−2.50 to −0.24)* −1.62 (−2.78 to −0.48)** Kidney disease (Yes) −0.98 (−2.37 to 0.42) −1.45 (−2.84 to −0.06)* PHQ-9 (pr. SD) 0.22 (−0.24 to 0.69) 0.21 (−0.24 to 0.66)

Conclusion

In elderly cardiac patients, level of motivation is important to achieve benefits of CR. Future studies should address if motivation measured with BREQ-2 can be applied as a screening tool for elderly patients to provide more personalized intervention.

Effect of high-intensity training versus moderate training on peak oxygen uptake and chronotropic response in heart transplant recipients: a randomized crossover trial

In heart transplant (HTx) recipients, there has been reluctance to recommend high-intensity interval training (HIIT) due to denervation and chronotropic impairment of the heart. We compared the effects of 12 weeks' HIIT versus continued moderate exercise (CON) on exercise capacity and chronotropic response in stable HTx recipients >12 months after transplantation in a randomized crossover trial. The study was completed by 16 HTx recipients (mean age 52 years, 75% males). Baseline peak oxygen uptake (VO2peak ) was 22.9 mL/kg/min. HIIT increased VO2peak by 4.9 ± 2.7 mL/min/kg (17%) and CON by 2.6 ± 2.2 mL/kg/min (10%) (significantly higher in HIIT; p < 0.001). During HIIT, systolic blood pressure decreased significantly (p = 0.037) with no significant change in CON (p = 0.241; between group difference p = 0.027). Peak heart rate (HRpeak ) increased significantly by 4.3 beats per minute (p = 0.014) after HIIT with no significant change in CON (p = 0.34; between group difference p = 0.027). Heart rate recovery (HRrecovery ) improved in both groups with a trend toward greater improvement after HIIT. The 5-month washout showed a significant loss of improvement. HIIT was well tolerated, had a superior effect on oxygen uptake, and led to an unexpected increase in HRpeak accompanied by a faster HRrecovery . This indicates that the benefits of HIIT are partly a result of improved chronotropic response.

NIH consensus development conference draft statement on vaginal birth after cesarean: new insights

OBJECTIVE

To provide health care providers, patients, and the general public with a responsible assessment of currently available data on vaginal birth after cesarean (VBAC).

PARTICIPANTS

A non-DHHS, nonadvocate 15-member panel representing the fields of obstetrics and gynecology, urogynecology, maternal and fetal medicine, pediatrics, midwifery, clinical pharmacology, medical ethics, internal medicine, family medicine, perinatal and reproductive psychiatry, anesthesiology, nursing, biostatistics, epidemiology, health care regulation, risk management, and a public representative, and a public representative. In addition, 21 experts from pertinent fields presented data to the panel and conference audience.

EVIDENCE

Presentations by experts and a systematic review of the literature prepared by the Oregon Evidence-based Practice Center, through the Agency for Healthcare Research and Quality. Scientific evidence was given precedence over anecdotal experience.

CONFERENCE PROCESS

The panel drafted its statement based on scientific evidence presented in open forum and on published scientific literature. The draft statement was presented on the final day of the conference and circulated to the audience for comment. The panel released a revised statement later that day at http://consensus.nih.gov. This statement is an independent report of the panel and is not a policy statement of the NIH or the Federal Government.

CONCLUSIONS

Given the available evidence, trial of labor is a reasonable option for many pregnant women with one prior low transverse uterine incision. The data reviewed in this report show that both trial of labor and elective repeat cesarean delivery for a pregnant woman with one prior transverse uterine incision have important risks and benefits and that these risks and benefits differ for the woman and her fetus. This poses a profound ethical dilemma for the woman, as well as her caregivers, because benefit for the woman may come at the price of increased risk for the fetus and vice versa. This conundrum is worsened by the general paucity of high-level evidence about both medical and nonmedical factors, which prevents the precise quantification of risks and benefits that might help to make an informed decision about trial of labor compared with elective repeat cesarean delivery. The panel was mindful of these clinical and ethical uncertainties in making the following conclusions and recommendations. One of the panel’s major goals is to support pregnant women with one prior transverse uterine incision to make informed decisions about trial of labor compared with elective repeat cesarean delivery. The panel recommends that clinicians and other maternity care providers use the responses to the six questions, especially questions 3 and 4, to incorporate an evidence-based approach into the decisionmaking process. Information, including risk assessment, should be shared with the woman at a level and pace that she can understand. When trial of labor and elective repeat cesarean delivery are medically equivalent options, a shared decisionmaking process should be adopted and, whenever possible, the woman’s preference should be honored. The panel is concerned about the barriers that women face in gaining access to clinicians and facilities that are able and willing to offer trial of labor. Given the low level of evidence for the requirement for "immediately available" surgical and anesthesia personnel in current guidelines, the panel recommends that the American College of Obstetricians and Gynecologists and the American Society of Anesthesiologists reassess this requirement with specific reference to other obstetric complications of comparable risk, risk stratification, and in light of limited physician and nursing resources. Healthcare organizations, physicians, and other clinicians should consider making public their trial of labor policies and VBAC rates, as well as their plans for responding to obstetric emergencies. The panel recommends that hospitals, maternity care providers, healthcare and professional liability insurers, consumers, and policymakers collaborate on the development of integrated services that could mitigate or even eliminate current barriers to trial of labor. The panel is concerned that medical-legal considerations add to, and in many instances exacerbate, these barriers to trial of labor. Policymakers, providers, and other stakeholders must collaborate in developing and implementing appropriate strategies to mitigate the chilling effect the medical-legal environment has on access to care. High-quality research is needed in many areas. The panel has identified areas that need attention in response to question 6. Research in these areas should be given appropriate priority and should be adequately funded--especially studies that would help to characterize more precisely the short-term and long-term maternal, fetal, and neonatal outcomes of trial of labor and elective repeat cesarean delivery.

The demographic impact of extreme events: stochastic weather drives survival and population dynamics in a long-lived seabird

1. Most scenarios for future climate change predict increased variability and thus increased frequency of extreme weather events. To predict impacts of climate change on wild populations, we need to understand whether this translates into increased variability in demographic parameters, which would lead to reduced population growth rates even without a change in mean parameter values. This requires robust estimates of temporal process variance, for example in survival, and identification of weather covariates linked to interannual variability. 2. The European shag Phalacrocorax aristotelis (L.) shows unusually large variability in population size, and large-scale mortality events have been linked to winter gales. We estimated first-year, second-year and adult survival based on 43 years of ringing and dead recovery data from the Isle of May, Scotland, using recent methods to quantify temporal process variance and identify aspects of winter weather linked to survival. 3. Survival was highly variable for all age groups, and for second-year and adult birds process variance declined strongly when the most extreme year was excluded. Survival in these age groups was low in winters with strong onshore winds and high rainfall. Variation in first-year survival was not related to winter weather, and process variance, although high, was less affected by extreme years. A stochastic population model showed that increasing process variance in survival would lead to reduced population growth rate and increasing probability of extinction. 4. As in other cormorants, shag plumage is only partially waterproof, presumably an adaptation to highly efficient underwater foraging. We speculate that this adaptation may make individuals vulnerable to rough winter weather, leading to boom-and-bust dynamics, where rapid population growth under favourable conditions allows recovery from periodic large-scale weather-related mortality. 5. Given that extreme weather events are predicted to become more frequent, species such as shags that are vulnerable to such events are likely to exhibit stronger reductions in population growth than would be expected from changes in mean climate. Vulnerability to extreme events thus needs to be accounted for when predicting the ecological impacts of climate change.

Conspecific reproductive success affects age of recruitment in a great cormorant, Phalacrocorax carbo sinensis, colony

Few studies have addressed the proximate factors affecting the age at which individuals of long-lived bird species are recruited into the breeding population. We use capture-recapture analysis of resightings of 16 birth cohorts of colour-ringed great cormorants, Phalacrocorax carbo sinensis, in a Danish colony to assess the evidence for two hypotheses: conspecific attraction (earlier recruitment when the colony is large) and conspecific reproductive success (earlier recruitment following years of high breeding success). For both males and females, conspecific reproductive success was the most important covariate explaining the interannual variation in age of recruitment; colony size was also important for females. These covariates explained nearly 60% of the year-to-year variation for both sexes. The age of recruitment increased for cohorts born after 1990, and this increase was correlated with a decline in breeding success in the colony; we interpret this as an indirect and delayed density-dependent effect. Females were recruited earlier than males (mean age of recruitment for cohorts born before 1990: 2.98 years versus 3.53 years); the most plausible reason for this is a skewed sex ratio in favour of males in the adult population. Recruitment of males may thus, to some extent, be constrained by the availability of females. This study provides the first evidence that conspecific reproductive success can affect the age at which individual birds start to breed.

Management of twin pregnancies consisting of a complete hydatidiform mole and normal fetus

OBJECTIVE

To report the clinical features, management, and outcome of twin pregnancies consisting of a complete hydatidiform mole and a coexisting normal fetus.

METHODS

Between 1966 and 1997, seven women with complete hydatidiform mole and coexisting normal fetus were treated at the John I. Brewer Trophoblastic Disease Center of Northwestern University Medical School. Clinical features, including presenting symptoms, gestational dates, hCG levels, and complications, as well as route of delivery or evacuation, pregnancy outcome, genetic analysis, and need for chemotherapy were assessed.

RESULTS

Four women required uterine evacuation before 20 weeks' gestation because of vaginal bleeding or medical complications, one woman required an emergency hysterotomy because of hemorrhage at 24 weeks, and two women delivered normal, viable infants at 26 and 34 weeks. The pathologic diagnosis of complete hydatidiform mole was confirmed in each case and the chromosome complement was 46,XX in all molar gestations. Four of seven women required chemotherapy for treatment of nonmetastatic gestational trophoblastic tumors, including both women who delivered viable infants and two of the five women whose pregnancies were evacuated before 24 weeks' gestation. All four patients were treated with five to seven cycles of a 5-day methotrexate regimen and achieved complete remission.

CONCLUSION

Patients with a twin pregnancy consisting of a complete mole and a normal fetus are at increased risk for hemorrhage and medical complications, as well as the development of persistent gestational trophoblastic tumor.

[Endocarditis--clinical picture of native valve infection]

In a population of 930,000 inhabitants all records of native valve infective endocarditis diagnosed in the decade 1980-89 were reviewed. One hundred and thirty-two cases were found, of whom 23 were not diagnosed until postmortem. Median prehospital duration of symptoms was 20 days (range 0-180) and median in-hospital diagnostic delay five days (range 0-54). Known cardiac disease was found in 42%, possible portal of entry in 33%, but in 36% no predisposing factors were found. During the clinical course 55% experienced cardiac failure and 17% embolic episodes. Surgery was required in 19 patients. Of 111 culture positive cases, streptococci were found in 61 and staphylococci in 45 cases. Overall mortality was 33% with a mortality of clinically diagnosed cases of 18%. Native valve endocarditis is thus associated with a significant mortality in part due to significant diagnostic delays and a large number of post-mortem diagnosed cases. Only by securing a high level of alertness towards endocarditis can we expect a reduced mortality.

Native valve infective endocarditis in the general population: a 10-year survey of the clinical picture during the 1980s

In a population of 930,000 inhabitants all records of native valve infective endocarditis diagnosed in the decade 1980-89 were reviewed. Using strict case definitions 132 clinically well-defined or post-mortem diagnosed cases were found. Included were cases referred to the local department of cardiology, as well as cases treated in non-specialized departments. Of 132 cases found 23 were only diagnosed post mortem. The male/female ratio was 71/61. The median prehospital duration of symptoms was 20 days (range 0-180 days) and the median in-hospital diagnostic delay was 5 days (range 0-54 days). Known cardiac disease was found in 42% of cases, a possible portal of entry was found in 33%, but in 36% there were no predisposing factors. Remarkably, only two patients had known rheumatic heart disease and none had a known dental focus. During the clinical course 55% experienced cardiac failure and 17% embolic episodes. In 19 patients surgery was required. Of 111 culture-positive cases streptococci were found in 61 and staphylococci in 45 cases. Echocardiography was performed in 95 cases with echocardiographic signs of endocarditis in 65 patients. Overall mortality was 33% with a mortality in clinically diagnosed cases of 18%. Of 14 cases needing immediate surgical intervention, two died.

Anaphylactic reaction during immunotherapy related to alcohol consumption

A case of anaphylaxis related to alcohol consumption during immunotherapy is reported. We advise to consider whether there has been noticeable alcohol consumption prior to each injection.

Circadian variation in the pharmacokinetics of verapamil

Circadian variation in the metabolism of verapamil was investigated in 10 patients with stable angina pectoris during treatment with sustained-release verapamil 360 mg at 08.00 h or 22.0 h. No major difference in exercise parameters was found. During the evening dosage schedule a significantly greater bioavailability (AUC) and a prolonged time to peak concentration was found. During the night (24.00 h-06.00 h) the half-life of verapamil was significantly longer than during the day (16.00 h-22.00 h). These differences in pharmacokinetics may be due to reduced hepatic blood flow at night or to circadian variation in hepatic microsomal metabolism.