Metal forms and dynamics in urban stormwater runoff: New insights from diffusive gradients in thin-films (DGT) measurements.

Stormwater runoff typically contains significant quantities of metal contaminants that enter urban waterways over short durations and represent a potential risk to water quality. The origin of metals within the catchment and processes that occur over the storm can control the partitioning of metals between a range of different forms. Understanding the fraction of metals present in a form that is potentially bioavailable to aquatic organisms is useful for environmental risk assessment. To help provide this information, the forms and dynamics of metal contaminants in an urban system were assessed across a storm. Temporal patterns in the concentration of metals in dissolved and particulate (total suspended solids; TSS) forms were assessed from water samples, and diffusive gradients in thin-films (DGTs) were deployed to measure the DGT-labile time-integrated metal concentration. Results indicate that the concentrations of dissolved and TSS-associated metals increased during the storm, with the metals Al, Cd, Co, Cu, Pb and Zn representing the greatest concern relative to water quality guideline values (GVs). The portion of labile metal as measured by DGT devices indicated that during the storm a substantial fraction (∼98%) of metals were complexed and pose a lower risk of acute toxicity to aquatic organisms. Comparison of DGT results to GVs indicate that current GVs are likely quite conservative when assessing stormwater pollution risks with regards to metal contaminants. This study provides valuable insight into the forms and dynamics of metals in an urban system receiving stormwater inputs and assists with the development of improved approaches for the assessment of short-term, intermittent discharge events.

Growth Performance and Plasma Metabolites of Grazing Beef Cattle Backgrounded on Buffel or Buffel-Desmanthus Mixed Pastures.

Dietary crude protein and dry matter digestibility are among the major factors limiting feed intake and weight gain of cattle grazing native and improved pastures in the subtropics of Northern Australia during the dry season. Incorporating a suitable legume into grasses improves pasture quality and cattle weight gain, but only a limited number of legume pastures can establish and persist in cracking clay soils. This study aimed to evaluate the effect of Desmanthus inclusion in buffel grass (Cenchrus ciliaris) pastures on the plasma metabolite profile and growth performance of grazing beef cattle during the dry season. We hypothesised that backgrounding steers on buffel grass-Desmanthus mixed pastures would elicit significant changes in plasma glucose, bilirubin, creatinine, non-esterified fatty acids and ß-hydroxybutyrate, resulting in higher liveweight gains than in steers on buffel grass only pastures. Four hundred tropical composite steers were assigned to buffel grass only (n = 200) or buffel grass oversown with Desmanthus (11.5% initial sward dry matter) pastures (n = 200) and grazed for 147 days during the dry season. Desmanthus accounted for 6.2% sward dry matter at the end of grazing period. Plasma metabolites results showed that changes in ß-hydroxybutyrate, creatinine, bilirubin, glucose and non-esterified fatty acids were within the expected normal range for all the steers, indicating that with or without Desmanthus inclusion in the diet of grazing steers, animal health status was not compromised. It was also evident that Desmanthus inclusion in buffel grass pastures had no impact on the plasma metabolite profile, liveweight and daily weight gain of grazing steers. Therefore, our tested hypothesis of higher changes in plasma metabolite profile and higher liveweight gains due to backgrounding on low-level buffel grass-Desmanthus mixed pastures does not hold.

Toward a Global Understanding of Chemical Pollution: A First Comprehensive Analysis of National and Regional Chemical Inventories.

Chemicals, while bringing benefits to society, may be released during their lifecycles and possibly cause harm to humans and ecosystems. Chemical pollution has been mentioned as one of the planetary boundaries within which humanity can safely operate, but is not comprehensively understood. Here, 22 chemical inventories from 19 countries and regions are analyzed to achieve a first comprehensive overview of chemicals on the market as an essential first step toward a global understanding of chemical pollution. Over 350 000 chemicals and mixtures of chemicals have been registered for production and use, up to three times as many as previously estimated and with substantial differences across countries/regions. A noteworthy finding is that the identities of many chemicals remain publicly unknown because they are claimed as confidential (over 50 000) or ambiguously described (up to 70 000). Coordinated efforts by all stakeholders including scientists from different disciplines are urgently needed, with (new) areas of interest and opportunities highlighted here.

Role-Emerging Clinical Placements in a Community-Based HIV Organization - Opportunities for Interprofessional Collaboration: A Case Report.

Purpose: We describe the development, implementation, and outcomes of role-emerging (RE) clinical placements at Positive Living Niagara (PLN), a community-based HIV organization (CBHIVO), for two second-year, entry-level Master of Science (Physiotherapy) (MSc[PT]) students from McMaster University. Client Description: A national, not-for-profit organization, Realize, conducted outreach to identify CBHIVOs interested in developing physiotherapy (PT) student placements. Intervention: PLN responded to the outreach and worked with McMaster's MSc(PT) programme and Realize to establish two part-time RE PT student placements. The placement description and expectations were developed collaboratively by PLN, Realize, and the MSc(PT) programme. All PT students participating in their third 6-week clinical placement were eligible to apply. A registered occupational therapist and physiotherapist and PLN's programme services manager participated in a shared model to supervise the students' clinical and administrative activities. Measures and Outcome: These first RE PT placements in a Canadian CBHIVO were completed between November and December 2016. The evaluation of the student and placement included a learning contract and the Canadian Physiotherapy Assessment of Clinical Performance. Over 6 weeks, the students collaborated with people living with HIV (PLWHIV) who were members of PLN to identify a role for physiotherapists at PLN and led two health promotion workshops for PLN's members and staff. Implications: The RE PT placement identified future opportunities for physiotherapists at PLN. The experience also influenced one student's decision to apply after graduation for a newly created PT position that included working with PLWHIV.

Objectif : présenter la création, la mise en œuvre et les résultats de stages cliniques en milieux émergents (MÉ) au sein de Positive Living Niagara (PLN), un organisme communautaire voué au VIH (OCVIH) où ont séjourné deux étudiants à la maîtrise en physiothérapie de l'université McMaster. Description du client : un organisme à but non lucratif national, Realize, a demandé à des OCVIH s'ils aimeraient accueillir des stages en physiothérapie. Intervention : PLN a répondu et, conjointement avec le programme de maîtrise en physiothérapie de McMaster, a mis sur pied deux stages en physiothérapie à temps partiel en MÉ. PLN, Realize et le programme de maîtrise ont rédigé ensemble la description du stage et les attentes. Tous les étudiants en physiothérapie qui participaient à leur troisième stage clinique de six semaines étaient admissibles. Un ergothérapeute agréé, un physiothérapeute et le chef des services relatifs aux programmes de PLN ont participé à un modèle de supervision partagé des activités cliniques et administratives des étudiants. Mesures et résultats : Ces premiers stages de physiothérapie en MÉ tenus dans un OCVIH canadien ont eu lieu entre novembre et décembre 2016. L'évaluation de l'étudiant et du stage incluait un contrat d'apprentissage et l'évaluation du rendement clinique de la physiothérapie au Canada. Sur une période de six semaines, les étudiants ont collaboré avec des personnes vivant avec le VIH (PVVIH) membres de PLN pour déterminer le rôle des physiothérapeutes à PLN et ont dirigé deux ateliers de promotion de la santé pour les membres et le personnel de PLN. Conséquences : le stage en physiothérapie en MÉ a permis de relever de futures possibilités pour les physiothérapeutes à PLN. L'expérience a également incité un étudiant à postuler, après l'obtention de son diplôme, à un nouveau poste de physiothérapeute auprès de PVVIH.

Unmet basic needs negatively affect health-related quality of life in people aging with HIV: results from the Positive Spaces, Healthy Places study.

BACKGROUND: Basic needs (e.g., food security and stable housing) are important determinants of health and well-being, yet their impact on health-related quality of life (HRQoL) in the context of HIV and aging has not been systematically investigated. METHODS: Multiple linear regression models examined the relationship between unmet basic needs, and physical and mental HRQoL by age strata (20-34, 35-49 and 50+) in a cross-sectional sample of 496 people living with HIV in Ontario, Canada. RESULTS: An overwhelming majority of participants (87%) reported unmet needs related to food, clothing or housing. The prevalence of unmet basic needs in the two older groups appeared to be lower than among younger participants, but the difference did not reach statistical significance. The presence of unmet basic needs predicted substantially lower mean physical health and mental health summary scores in the two oldest groups. Notably, age moderated the influence of unmet basic needs on HRQoL. CONCLUSIONS: The availability and accessibility of food security, appropriate clothing and stable housing for people living with HIV who are aging need to become a higher priority for program planners and decision makers.

Elevated Mortality and Associated Social Determinants of Health in a Community-Based Sample of People Living with HIV in Ontario, Canada: Findings from the Positive Spaces, Healthy Places (PSHP) Study.

We examined social determinants of health associated with all-cause mortality among 602 people living with HIV/AIDS in Ontario, Canada. Mortality status was verified at 1-, 3-, and 5-year follow-up visits with information obtained from proxies (family members, partners, and friends), obituaries, and local AIDS memorial lists. Of the 454 people for whom mortality information was available, 53 individuals died yielding a crude mortality rate of 22.3 deaths per 1000 person-years, a rate substantially higher than the rate in the general population (6.8 per 1000 population). Experiencing both homelessness and incarceration independently predicted high risk of mortality among men who have sex with men (MSM) while suboptimal self-rated general health at previous visit predicted higher greater risk of mortality in both MSM and women and heterosexual men. Homelessness and incarceration may contribute to HIV disease progression and mortality. Intensive case management that increases retention in care and facilitates linkage to housing services may help to reduce excess deaths among people with HIV.

Ecological Risk Assessment of Nano-enabled Pesticides: A Perspective on Problem Formulation.

Plant protection products containing nanomaterials that alter the functionality or risk profile of active ingredients (nano-enabled pesticides) promise many benefits over conventional pesticide products. These benefits may include improved formulation characteristics, easier application, better targeting of pest species, increased efficacy, lower application rates, and enhanced environmental safety. After many years of research and development, nano-enabled pesticides are starting to make their way into the market. The introduction of this technology raises a number of issues for regulators, including how does the ecological risk assessment of nano-enabled pesticide products differ from that of conventional plant protection products? In this paper, a group drawn from regulatory agencies, academia, research, and the agrochemicals industry offers a perspective on relevant considerations pertaining to the problem formulation phase of the ecological risk assessment of nano-enabled pesticides.

Food insufficiency, housing and health-related quality of life: results from the Positive Spaces, Healthy Places study.

Studies of people living with HIV who are homeless or unstably housed show a high prevalence of food insufficiency (>50%) and associated poor health outcomes; however, most evidence is in the form of cross-sectional studies. To better understand this issue, we conducted a longitudinal study to examine the impact of food insufficiency and housing instability on overall physical and mental health-related quality of life (HRQoL) among people living with HIV in Ontario. Six hundred and two adults living with HIV were enrolled in the Positive Spaces, Healthy Places study and followed from 2006 to 2009. Interviewer-administered questionnaires were used, and generalized linear mixed-effects models constructed to examine longitudinal associations between food insufficiency, housing instability and physical and mental HRQoL. At baseline, 57% of participants were classified as food insufficient. After adjusting for potential confounders, longitudinal analyses revealed a significant, negative association between food insufficiency and physical and mental HRQoL outcomes, respectively [effect size (ES) with 95% confidence interval (CI): (ES = -2.1, CI = -3.9,-0.3); (ES = -3.5, CI = -6.1,-1.5)]. Furthermore, difficulties meeting housing costs were shown to have additional negative impacts on mental HRQoL. Food insufficiency is highly prevalent among people living with HIV in Ontario, particularly for those with unstable housing. This vulnerable group of individuals is in urgent need of changes to current housing programmes, services and policies, as well as careful consideration of their unmet nutritional needs.

Predicting aquifer response time for application in catchment modeling.

It is well established that changes in catchment land use can lead to significant impacts on water resources. Where land-use changes increase evapotranspiration there is a resultant decrease in groundwater recharge, which in turn decreases groundwater discharge to streams. The response time of changes in groundwater discharge to a change in recharge is a key aspect of predicting impacts of land-use change on catchment water yield. Predicting these impacts across the large catchments relevant to water resource planning can require the estimation of groundwater response times from hundreds of aquifers. At this scale, detailed site-specific measured data are often absent, and available spatial data are limited. While numerical models can be applied, there is little advantage if there are no detailed data to parameterize them. Simple analytical methods are useful in this situation, as they allow the variability in groundwater response to be incorporated into catchment hydrological models, with minimal modeling overhead. This paper describes an analytical model which has been developed to capture some of the features of real, sloping aquifer systems. The derived groundwater response timescale can be used to parameterize a groundwater discharge function, allowing groundwater response to be predicted in relation to different broad catchment characteristics at a level of complexity which matches the available data. The results from the analytical model are compared to published field data and numerical model results, and provide an approach with broad application to inform water resource planning in other large, data-scarce catchments.

Using MODFLOW 2000 to model ET and recharge for shallow ground water problems.

In environments with shallow ground water elevation, small changes in the water table can cause significant variations in recharge and evapotranspiration fluxes. Particularly, where ground water is close to the soil surface, both recharge and evapotranspiration are regulated by a thin unsaturated zone and, for accuracy, must be represented using nonconstant and often nonlinear relationships. The most commonly used ground water flow model today, MODFLOW, was originally designed with a modular structure with independent packages representing recharge and evaporation processes. Systems with shallow ground water, however, may be better represented using either a recharge function that varies with ground water depth or a continuous recharge and evapotranspiration function that is dependent on depth to water table. In situations where the boundaries between recharging and nonrecharging cells change with time, such as near a seepage zone, a continuous ground water flux relationship allows recharge rates to change with depth rather than having to calculate them at each stress period. This research article describes the modification of the MODFLOW 2000 recharge and segmented evapotranspiration packages into a continuous recharge-discharge function that allows ground water flux to be represented as a continuous process, dependent on head. The modifications were then used to model long-term recharge and evapotranspiration processes on a saline, semiarid floodplain in order to understand spatial patterns of salinization, and an overview of this process is given.

Influence of pasture and concentrates in the diet of grazing dairy cows on the fatty acid composition of milk.

In five short-term experiments conducted in Victoria in 1997 and 1998, grazing dairy cows were given either pasture alone or pasture supplemented with high-energy concentrates, and the fatty acid profiles of milk fat were measured. We established the effects of these feeds on some aspects of milk fat of importance for human nutrition, but we specifically focused on the hypothesis that conjugated linoleic acid (CLA) concentrations in milk fat increase as pasture intake increases, and decrease as more concentrates are fed. In agreement with previous research, feeding fresh pasture alone resulted in high concentrations (1.0-1.8 g/100 g milk fat) of CLA. When the effect of level of pasture consumption on CLA content was examined, a significant positive relationship (r2 = 0.35; P < 0.05) was obtained. When cereal grain concentrates were used to supplement pasture intake, the CLA content of milk fat generally declined (P < 0.05), except where the amount of concentrates given led to a marked reduction in total milk fat concentration. The use of cereal grain concentrates also generally resulted in significant (P < 0.05) increases in medium-chain saturated fatty acids, but always reduced the contribution of butyric acid to milk fat, from 4.5 to 3.9 g/100 g milk fat, on average.

Variations in stream water uptake by Eucalyptus camaldulensis with differing access to stream water.

The stable isotopes 2H and 18O were used to determine the water sources of Eucalyptus camaldulensis at three sites with varying exposure to stream water, all underlain by moderately saline groundwater. Water uptake patterns were a function of the long-term availability of surface water. Trees with permanent access to a stream used some stream water at all times. However, water from soils or the water table commonly made up 50% of these trees' water. Trees beside an ephemeral stream had access to the stream 40-50% of the time (depending on the level of the stream). No more than 30% of the water they used was stream water when it was available. However, stream water use did not vary greatly whether the trees had access to the stream for 2 weeks or 10 months prior to sampling. Trees at the third site only had access to surface water during a flood. These trees did not change their uptake patterns during 2 months inundation compared with dry times, so were not utilising the low-salinity flood water. Pre-dawn leaf water potentials and leaf 13C measurements showed that the trees with permanent access to the stream experienced lower water stress and had lower water use efficiencies than trees at the least frequently flooded site. The trees beside the ephemeral stream appeared to change their water use efficiency in response to the availability of surface water; it was similar to the perennial-stream trees when stream water was available and higher at other times. Despite causing water stress, uptake of soil water and groundwater would be advantageous to E. camaldulensis in this semi-arid area, as it would provide the trees with a supply of nutrients and a reliable source of water. E. camaldulensis at the study site may not be as vulnerable to changes in stream flow and water quality as previously thought.

Sources of water used by riparian Eucalyptus camaldulensis overlying highly saline groundwater.

Water sources of Eucalyptus camaldulensis Dehn. trees were investigated on a semiarid floodplain in south-eastern Australia. The trees investigated ranged in distance from 0.5 to 40 m from a stream, with electrical conductivity 0.8 dSm-1, and grew over groundwater with electrical conductivity ranging from 30 to 50 dSm-1. The sources of water being used by the trees were investigated using the naturally occurring stable isotopes of water and measurements of soil water potential. Xylem water potential and leaf conductance were also examined to identify the trees' response to using these sources of water. Trees at distances greater than about 15 m from the stream used no stream water. The trees used groundwater in summer and a combination of groundwater and rain-derived surface-soil water (0.05-0.15 m depth) in winter. In doing so they suffered water stress at electrical conductivities higher than approximately 40 dSm-1 (equivalent to approximately -1.4 MPa). Trees adjacent to the stream used stream water directly in summer, but may have used stream water from the soil profile in winter, after the stream had risen and recharged the soil water. E. camaldulensis appeared to be partially opportunistic in the sources of water they used.