Considerations and data update for the inference of environmental quality standards for two avermectins widely used in salmon aquaculture

We have updated and reviewed toxicity data for Emamectin benzoate (EMB) and Ivermectin (IVER), two in-feed drugs used to treat sea lice in farmed Atlantic salmon, and inferred new Environmental Quality Standards (EQS) using a deterministic approach or Species Sensitivity Distributions (SSDs) based on available data. We used a SSD model averaging approach and inferred a water acute EQS value of 24.9 ng/L (SSD) for EMB, while previously established chronic water EQS of 0.17 ng/L and sediment benthic EQS of 131 ng/kg dry weight remained unchanged. For IVER, both a water acute EQS of 8.04 ng/L and a chronic water EQS of 3.98 ng/L were inferred using SSDs as well as a benthic EQS of 290 ng/kg dry weight using a deterministic approach. In light of the lack of solubility and tendency of both avermectins to sorb to material benthic EQSs remain the most relevant value to consider for regulators.

The persistence of emamectin benzoate in marine sediments with different organic matter regimes, temperature conditions, and antibiotic presence

The objectives of this 318-day study are to determine half-lives of the anti-sea lice medication emamectin benzoate (EMB) under conditions present in sediments at aquaculture sites and document the degradation of EMB into its main metabolite desmethyl emamectin benzoate (DES). Tested conditions include different matrix types (sand, mud), two temperatures (4, 10 degrees), organic matter presence (fish feed waste and feces), and the presence of oxytetracycline. We document a transformation ratio of EMB to DES of 0.16 to 4.4 % and show that the co-presence of oxytetracycline increases EMB calculated half-lives to values >6000 days for mud matrices. EMB incubated in high organic enrichment regimes was not observed to degrade at 4 degrees. Multivariate analyses show interactions between sediment conditions (matrix, temperature, organic matter [OM], oxytetracycline) influence EMB persistence and DES:EMB ratios. Ranges of EMB half-lives and information on metabolites can be used to anticipate potential effects on marine communities.

Metabolization of emamectin benzoate into desmethyl emamectin benzoate in spiked marine sediments

Emamectin benzoate (EMB) (4″deoxy- 4″-epi-methylaminoavermectin) is a pesticide developed to control pests on various crops, and in forestry. It is also used in salmon aquaculture to control sea lice infestations as an in-feed therapeutant. Little is known about EMB metabolites and potential associated toxicities in marine sediments. In this study, we used natural marine sediments (sand and mud) fortified at an EMB concentration of 60 ppb (wet weight). Results show an almost immediate transformation of EMB to Desmethyl EMB (DES) with no increased rates of metabolization when stored sediment samples were incubated for up to 16 h. The transformation ratio of EMB to DES represented between 0.16 and 0.39% of EMB; values are lower than what has been observed in fish tissue. Data suggest that DES is generated through both abiotic (tested after autoclaving marine sediments) and biological processes. Further work on freshly sampled marine sediments with EMB deposits, different organic regimes, and a detailed assessment of active bacterial communities are necessary to better evaluate the EMB to DES rate of transformation around aquaculture sites.

Species sensitivity distributions for two widely used anti-sea lice chemotherapeutants in the salmon aquaculture industry

The main objective of the present study is to construct acute aquatic species sensitivity distributions (SSD) and generate proposed HC₅ values (i.e. the hazardous concentration for which 5 % of species are affected or potentially affected) for two aquaculture anti-sea lice bath pesticides, azamethiphos, and hydrogen peroxide. These values could be used as the basis for the establishment of environmental quality standards (EQS). We have generated SSDs and inferred HC₅ values for mortality and sublethal endpoints using LC50, EC50, and NOEC/LOEC data points separately and for each bath pesticide. Through the examination of literature data on the toxicity of both compounds, we opted to use tests with limited exposure times to ensure environmental relevance for bath pesticides. We also separated life stages for some of the sensitive taxa to account for differences in sensitivities and risk of exposure. The resulting threshold concentrations in environmental seawater are 0.10 μg/L for azamethiphos and 0.15 mg/L for hydrogen peroxide. These suggested azamethiphos and hydrogen peroxide thresholds are comparable to some previously reported EQS values. Further considerations need to be included in how to better use these thresholds in a regulatory context in relation to dispersion patterns. It is also clear that delayed mortality and sublethal effects documented in the literature require further study to fully anticipate the environmental risks of using these two bath pesticides.

Adolescents' knowledge of a peer's non-suicidal self-injury and own non-suicidal self-injury and suicidality

OBJECTIVE

Some research suggests that suicidal ideation and attempt among adolescents may be contagious - that is adolescents who are exposed to peers' suicidal behaviour are more likely to experience suicidal ideation or attempt suicide themselves. Less is known about the potential contagion effect of non-suicidal self-injury (NSSI). Our objective was to determine whether knowledge of a friend's NSSI is associated with adolescent's own non-suicidal self-injury and suicidal behaviours.

METHODS

Data from 1483 youth ages 14-17 years were obtained from the 2014 Ontario Child Health Study, a cross-sectional population-based survey of children and adolescents in Ontario, Canada. Logistic regression models were used to examine associations between knowledge of a friend's NSSI and adolescents' own self-reported self-injurious and suicidal behaviours. Interactions with gender, age group and presence of a mental disorder were investigated.

RESULTS

Knowledge of a friend's non-suicidal self-injury was significantly associated with the adolescent's own non-suicidal self-injury (OR = 2.03, 95% CI 1.05-3.90), suicidal ideation (OR = 3.08, 95% CI 1.50-6.30) and suicide attempt (OR = 2.87, 95% CI 1.20-6.87).

CONCLUSION

These findings suggest an apparent contagion effect for non-suicidal self-injury. Awareness of a friend's self-injurious behaviours is associated with an adolescent's own self-injury and suicidality. Interventions aimed at preventing NSSI and suicidality should consider prevention of possible contagion at the school and/or community level.

Lifetime experience of multiple common mental disorders and 19-year mortality: results from a Canadian population-based cohort

AIMS

To examine the impact of multiple psychiatric disorders over the lifetime on risk of mortality in the general population.

METHODS

Data came from a random community-based sample of 1397 adults in Atlantic Canada, recruited in 1992. Major depression, dysthymia, panic disorder, generalised anxiety disorder and alcohol use disorders were assessed using the Diagnostic Interview Schedule (DIS). Vital status of participants through 2011 was determined using probabilistic linkages to the Canadian Mortality Database. Cox proportional hazard models with age at study entry as the time scale were used to investigate the relationship between DIS diagnoses and mortality, adjusted for participant education, smoking and obesity at baseline.

RESULTS

Results suggested that mood and anxiety disorders rarely presented in isolation - the majority of participants experienced multiple psychiatric disorders over the lifetime. Elevated risk of death was found among men with both major depression and dysthymia (HR 2.56; 95% CI 1.12-5.89), depression and alcohol use disorders (HR 2.45; 95% CI 1.18-5.10) and among men and women who experienced both panic disorder and alcohol use disorders (HR 3.80; 95% CI 1.19-12.16).

CONCLUSION

The experience of multiple mental disorders over the lifetime is extremely common, and associated with increased risk of mortality, most notably among men. Clinicians should be aware of the importance of considering contemporaneous symptoms of multiple psychiatric conditions.

Consistency in adult reporting of adverse childhood experiences

BACKGROUND

Many studies have used retrospective reports to assess the long-term consequences of early life stress. However, current individual characteristics and experiences may bias the recall of these reports. In particular, depressed mood may increase the likelihood of recall of negative experiences. The aim of the study was to assess whether specific factors are associated with consistency in the reporting of childhood adverse experiences.

METHOD

The sample comprised 7466 adults from Canada's National Population Health Survey who had reported on seven childhood adverse experiences in 1994/1995 and 2006/2007. Logistic regression was used to explore differences between those who consistently reported adverse experiences and those whose reports were inconsistent.

RESULTS

Among those retrospectively reporting on childhood traumatic experiences in 1994/1995 and 2006/2007, 39% were inconsistent in their reports of these experiences. The development of depression, increasing levels of psychological distress, as well as increasing work and chronic stress were associated with an increasing likelihood of reporting a childhood adverse experience in 2006/2007 that had not been previously reported. Increases in mastery were associated with reduced likelihood of new reporting of a childhood adverse experience in 2006/2007. The development of depression and increases in chronic stress and psychological distress were also associated with reduced likelihood of 'forgetting' a previously reported event.

CONCLUSIONS

Concurrent mental health factors may influence the reporting of traumatic childhood experiences. Studies that use retrospective reporting to estimate associations between childhood adversity and adult outcomes associated with mental health may be biased.

Trajectories of childhood neighbourhood cohesion and adolescent mental health: evidence from a national Canadian cohort

BACKGROUND

The objective of this study was to examine associations between trajectories of childhood neighbourhood social cohesion and adolescent mental health and behaviour.

METHOD

This study used data from the National Longitudinal Survey of Children and Youth, a nationally representative sample of Canadian children. The sample included 5577 children aged 0-3 years in 1994-1995, prospectively followed until age 12-15 years. Parental perceived neighbourhood cohesion was assessed every 2 years. Latent growth class modelling was used to identify trajectories of neighbourhood cohesion. Mental health and behavioural outcomes were self-reported at age 12-15 years. Logistic regression was used to examine associations between neighbourhood cohesion trajectories and outcomes, adjusting for potential confounders.

RESULTS

Five distinct trajectories were identified: 'stable low' (4.2%); 'moderate increasing' (9.1%); 'stable moderate' (68.5%); 'high falling' (8.9%); and 'stable high' (9.3%). Relative to those living in stable moderately cohesive neighbourhoods, those in stable low cohesive neighbourhoods were more likely to experience symptoms of anxiety/depression [odds ratio (OR) = 1.73, 95% confidence interval (CI) 1.04-2.90] and engage in indirect aggression (OR = 1.62, 95% CI 1.07-2.45). Those with improvements in neighbourhood cohesion had significantly lower odds of hyperactivity (OR = 0.67, 95% CI 0.46-0.98) and indirect aggression (OR = 0.69, 95% CI 0.49-0.96). In contrast, those with a decline in neighbourhood cohesion had increased odds of hyperactivity (OR = 1.67, 95% CI 1.21-2.29). Those in highly cohesive neighbourhoods in early childhood were more likely to engage in prosocial behaviour ('high falling': OR = 1.93, 95% CI 1.38-2.69; 'stable high': OR = 1.89, 95% CI 1.35-2.63).

CONCLUSIONS

These results suggest that neighbourhood cohesion in childhood may have time-sensitive effects on several domains of adolescent mental health and behaviour.

Leading the change process. Interview by Michael L. Laughlin and Carolyn Dunbar

'Change or cease to exist.' In interviews with Computers in Healthcare six industry leaders agree that increasing market pressures will force many organizations to drastically modify the way they do business. Those that don't will eventually fail.