Laboratory and In situ Selenium Bioaccumulation Assessment in the Benthic Macroinvertebrates Hyalella azteca and Chironomus dilutus.

Selenium (Se) bioaccumulation and toxicity in aquatic vertebrates have been thoroughly investigated. Limited information is available on Se bioaccumulation at the base of aquatic food webs. In this study, we evaluated Se bioaccumulation in two benthic macroinvertebrates (BMI), Hyalella azteca and Chironomus dilutus raised in the laboratory and caged in-situ to a Canadian boreal lake e (i.e., McClean Lake) that receives continuous low-level inputs of Se (< 1 µg/L) from a uranium mill. Additional Se bioaccumulation assays were conducted in the laboratory with these BMI to (i) confirm field results, (ii) compare Se bioaccumulation in lab-read and native H. azteca populations and (iii) identify the major Se exposure pathway (surface water, top 1 cm and top 2-3 cm sediment layers) leading to Se bioaccumulation in H. azteca. Field and laboratory studies indicated overall comparable Se bioaccumulation and trophic transfer factors (TTFs) in co-exposed H. azteca (whole-body Se 0.9-3.1 µg/g d.w; TTFs 0.6-6.3) and C. dilutus (whole-body Se at 0.7-3.2 µg Se/g d.w.; TTFs 0.7-3.4). Native and lab-reared H. azteca populations exposed to sediment and periphyton from McClean Lake exhibited similar Se uptake and bioaccumulation (NLR, p = 0.003; 4.1 ± 0.8 µg Se/g d.w), demonstrating that lab-reared organisms are good surrogates to assess on-site Se bioaccumulation potential. The greater Se concentrations in H. azteca exposed to the top 1-3 cm sediment layer relative to waterborne exposure, corroborates the importance of the sediment-detrital pathway leading to greater Se bioaccumulation potential to higher trophic levels via BMI.

Effects of diluted effluent on aquatic macroinvertebrate communities at the McClean Lake uranium operation in northern Saskatchewan.

Diluted treated effluent from the McClean Lake uranium mill in northern Saskatchewan is released into Vulture Lake, which flows into the east basin of McClean Lake; this input could potentially cause a variety of disturbances to the aquatic systems. This study aimed to determine the potential effects of diluted effluent exposure (metals and major ions) on benthic macroinvertebrates in Vulture Lake and McClean Lake. Two monitoring locations located in Vulture Lake and eight in McClean Lake were used for collection water, sediment, and benthic macroinvertebrates. Complementary surface water bioassays were performed with larvae of the midge Chironomus dilutus using lake water from selected sites. Results indicated that total macroinvertebrate abundance and Margalef index (MI) did not follow the diluted effluent pattern. In addition, while the MI from artificial substrate samplers showed higher values in Vulture Lake and lower values at McClean Lake sites 4 and 5 (closer to effluent diffuser), the values recorded for sediment grab samples registered lower indices in Vulture Lake and higher values for sites 4 and 5. The final model from a Generalized Additive Modelling (GAM) approach suggested that electrical conductivity (EC), selenium (Se), and chloride (Cl) in water, and total organic carbon (TOC) and cadmium (Cd) in sediment are key variables that collectively may have influenced macroinvertebrate community composition at the study sites. Finally, across all test endpoints in the bioassays, exposure to lake water from Vulture Lake and McClean Lake had no statistically significant effects on C. dilutus.

The influence of sampling method and season on modeling of selenium into coldwater fish and implications on tissue-based water quality benchmarks.

Selenium (Se) contamination of aquatic ecosystems has led to the local extirpation of some Se-sensitive fish species. Although Se exposure occurs primarily via diet, considerable uncertainty lies in modeling Se transfer and bioaccumulation from sediment, detritus, and/or periphyton through benthic macroinvertebrates (BMI) to fish. Here we estimated Se concentrations in four coldwater fish species (northern pike, white sucker, lake whitefish, and ninespine stickleback) inhabiting boreal lakes downstream from a uranium mill in northern Canada. In addition, we evaluated the potential effects of BMI and periphyton sampling methods (artificial substrates vs. grab samples), seasons (summer vs. winter), and models (USEPA vs. Assessment of the Dispersion and Effects of Parameter Transport) on the estimated Se concentrations in fish tissue. Results were compared with site-specific benchmarks and observed Se concentrations in resident fish. In summer 2019, periphyton and BMI were sampled at 10 sampling stations (two in Vulture Lake and eight in McClean Lake) using artificial substrates (n = 4) and sediment grab samples (n = 3). In winter 2021, samples were collected in McClean Lake (n = 3) through ice holes using a sediment grab sampler. Estimated Se concentrations in fish tissue depended on the surface sediment or periphyton Se concentrations used in the models. At Vulture Lake, Se concentrations in northern pike muscle estimated using the grab sample data (17.3 ± 11.5 µg/g DW), but not the artificial substrates (34.5 ± 1.2 µg/g DW), were comparable with the observed mean concentration (19.0 ± 1.4 µg/g DW) in this species. At McClean Lake, Se body burdens in forage fish estimated using data from both sampling methods were comparable with measured data. Significantly lower mean whole-body Se concentrations were estimated for all fish species in winter (1.0 ± 0.3 µg/g DW) relative to summer (4.8 ± 1.6 µg/g DW). Further investigation is necessary to understand how potential seasonal shifts in dietary Se exposure relate to fish reproduction and early life stages. Integr Environ Assess Manag 2023;00:1-15. © 2023 SETAC.

Sampling method and season influence selenium dynamics at the base of a boreal lake food chain.

Few studies have investigated the potential influence of sampling method and season on Se bioaccumulation at the base of the aquatic food chain. In particular, the effects of low water temperature associated with prolonged ice-cover periods on Se uptake by periphyton and further transfer to benthic macroinvertebrates (BMI) have been overlooked. Such information is crucial to help improve Se modelling and risk assessment at sites receiving continuous Se inputs. To date, this seems to be the first study to address these research questions. Here, we examined potential differences related to sampling methods (artificial substrates vs. grab samples) and seasons (summer vs. winter) on Se dynamics in the benthic food chain of a boreal lake (McClean Lake) receiving continuous low-level Se input from a Saskatchewan uranium milling operation. During summer 2019, water, sediment grab samples and artificial substrates were sampled from 8 sites with varying mill-treated effluent exposure. In winter 2021, water and sediment grab samples were sampled at 4 locations in McClean Lake. Water, sediment, and biological samples were subsequently analyzed for total Se concentrations. Enrichment functions (EF) in periphyton and trophic transfer factors (TTF) in BMI were calculated for both sampling methods and seasons. Periphyton collected with artificial substrates (Hester-Dendy samplers and glass plates) exhibited significantly higher mean Se concentrations (2.4 ± 1.5 µg/g d.w) than periphyton collected from the surface of sediment grab samples (1.1 ± 1.3 µg/g d.w). Selenium concentrations in periphyton sampled in winter (3.5 ± 1.0 µg/g d.w) were significantly greater than summer (1.1 ± 1.3 µg/g d.w). Nevertheless, Se bioaccumulation in BMI was similar between seasons, possibly suggesting that invertebrates are not actively feeding in winter. Further investigations are necessary to verify if peak Se bioaccumulation in BMI takes place in spring, coinciding with the reproductive and developmental windows of some fish species.

Application of autonomous sensor technology to estimate selenium exposure and a site-specific selenium threshold in a Canadian boreal lake.

There is an increasing trend in the use of real-time sensor technology to remotely monitor aquatic ecosystems. Commercially available probes, however, are currently not able to measure aqueous selenium (Se) concentrations. Because of the well-described bioaccumulation potential and associated toxicity of Se in oviparous vertebrates, it is crucial to monitor Se concentrations at sites receiving continuous effluent Se input. This study aimed to estimate Se concentrations in a boreal lake (McClean Lake) downstream from a Saskatchewan uranium mill using real-time electrical conductivity (EC) data measured by autonomous sensors. Additionally, this study aimed to derive a site-specific total aqueous Se (TSe) threshold based on Se concentrations in periphyton and benthic macroinvertebrates sampled from the same lake. To characterize effluent distribution within the lake, eight Smart Water (Libelium) sensor units were programmed to report EC and temperature for five and seven consecutive weeks in 2018 and 2019, respectively. In parallel, periphyton and benthic macroinvertebrates were sampled with Hester-Dendy's artificial substrate samplers (n = 4) at the same sites and subsequently analyzed for Se concentrations. Electrical conductivity was measured with a handheld field meter for sensor data validation and adjusted to the median lake water temperature (13 °C) registered for the deployment periods. Results demonstrated good accuracy of sensor readings relative to handheld field meter readings and the successful use of real-time EC in estimating TSe exposure (r = 0.87; r2 = 0.84). Linear regression equations derived for Se in detritivores versus Se in periphyton and Se in periphyton versus sensor-estimated TSe were used to estimate a site-specific TSe threshold of 0.7 µg/L (±0.2). Moreover, mean Se concentrations in periphyton (16.7 ± 4.4 µg/g dry weight [d.w.]) and benthic detritivores (6.0 ± 0.4 µg/g d.w.) from one of the exposure sites helped identify an area with potential for high Se bioaccumulation and toxicity in aquatic organisms in McClean Lake. Integr Environ Assess Manag 2023;19:395-411. © 2022 SETAC.

Selenium Distribution and Trophic Transfer in the Periphyton-Benthic Macroinvertebrate Food Chain in Boreal Lakes Downstream from a Milling Operation.

Selenium (Se) is an essential micronutrient with a narrow essentiality-toxicity range known to bioaccumulate in aquatic food webs. Selenium uptake and trophic transfer at the base of aquatic food chains represent a great source of uncertainty for Se risk assessment. The goal of the present study was to investigate Se distribution in water and sediment and its subsequent transfer into the periphyton-benthic macroinvertebrate (BMI) food chain in boreal lakes downstream from a Saskatchewan uranium mill. In particular, the present study aimed to assess potential differences in Se bioaccumulation patterns by BMI taxa to contribute to the current knowledge gap. During summer 2018 and 2019, water, sediment, periphyton, and BMI were sampled at two sites in Vulture Lake, seven sites in McClean Lake east basin, and one reference site in McClean Lake west basin. Periphyton and BMI taxa were sampled with artificial substrates (Hester-Dendy) deployed for 5 weeks in 2018 and 7 weeks in 2019; BMI were sorted into the lowest practical achievable taxonomic level and analyzed for total Se concentrations. At the diluted effluent exposure sites, Se concentrations in BMI ranged from 1.3 to 18.0 µg/g dry weight and from 0.3 to 49.3 µg/g dry weight in 2018 and 2019, respectively, whereas concentrations ranged from 0.01 to 3.5 µg/g dry weight at the reference site. Selenium concentrations in periphyton and some BMI taxa sampled near the effluent diffuser (Se < 1 µg/L) reached levels comparable to higher effluent exposure sites (Se > 2 µg/L). Despite differences in Se bioaccumulation among BMI taxa, an approximately one-to-one trophic transfer ratio was observed for benthic primary consumers and benthic predatory taxa. Environ Toxicol Chem 2022;41:2181-2192. © 2022 SETAC.

Delineating Effluent Exposure and Cumulative Ecotoxicological Risk of Metals Downstream of a Saskatchewan Uranium Mill Using Autonomous Sensors.

There is increasing interest in using autonomous sensor technology to monitor aquatic ecosystems in real time and in employing such monitoring data to perform better ecological risk assessments. At seven locations in McClean Lake in northern Saskatchewan (Canada) that received diluted uranium milling effluent, we deployed sensor units to track effluent distribution and help predict potential biological effects on aquatic invertebrates. Water was also collected from each location on multiple occasions to measure major ions, dissolved metals, and routine water quality, and sediment was sampled to analyze total metals. The ecotoxicological risk to aquatic invertebrates was estimated using hazard quotients (HQs). The cumulative risk was estimated by summing the individual HQs, and the major ions risk was based on total osmolarity. The results indicated temporal and spatial variations in effluent exposure based on sensor electrical conductivity (EC) measurements in the McClean Lake East Basin. Individual HQs for water ranged from "moderate" (0.40-0.69) to "very high" (greater than 1) for silver, cadmium, arsenic, selenium, mercury, iron, and thallium. At all sites, major ions risk was less than 1. Individual HQs for sediment were "moderate" (0.40-0.69), "high" (0.7-0.99), and "very high" (greater than 1) for vanadium and cadmium. The cumulative risk in water and sediment for all metals combined was greater than 1 at some sites in Vulture Lake (which discharged into McClean Lake) and in McClean Lake itself. A more detailed estimation of the risks for aqueous selenium and arsenic (the only two metals that had good correlation with sensor EC data) indicated that their 90th percentile HQ values were less than 1 in McClean Lake, suggesting that these contaminants of concern do not represent a significant direct risk to aquatic invertebrate communities. Environ Toxicol Chem 2022;41:1765-1777. © 2022 SETAC.

Potencialidades e fragilidades institucionais no cuidado ao idoso com hipertensão / Institutional strengths and weaknesses in the care of older adults with hypertension / Fortalezas y debilidades institucionales en el cuidado del adulto mayor con hipertensión

Objetivo: avaliar a capacidade institucional de cuidado ao paciente hipertenso nos serviços de saúde destinados aos idosos, a partir da percepção das equipes de saúde. Método: estudo transversal, com 53 profissionais de saúde das instituições ambulatoriais especializadas no cuidado ao idoso na cidade de Manaus, Amazonas, Brasil. Aplicou-se a Avaliação da Capacidade Institucional para Atenção às Condições Crônicas (ACIC). Os dados são apresentados em valores de média. Resultados: as potencialidades foram nas dimensões: autocuidado apoiado (6,1 ± 2,7), organização da atenção à saúde (5,5 ± 2,1) e desenho do sistema de prestação de serviços (5,1 ± 2,6). As fragilidades foram: sistema de informação clínica (3,9 ± 2,7), recursos da comunidade (4,0 ± 2,9), integração dos componentes do modelo de atenção (4,1 ± 2,7) e suporte às decisões (4,4 ± 2,9). Conclusão: de acordo com o ACIC, as instituições apresentaram capacidade básica na prestação de cuidado ao paciente hipertenso.

Objective: To evaluate the institutional capacity to care for hypertensive patients in health services for older adults, based on the perception of health teams. Method: A cross-sectional study with 53 health professionals from outpatient institutions specializing in the care of older adults in the city of Manaus, Amazonas, Brazil. The Institutional Capacity Assessment for Attention to Chronic Conditions (ACIC) was applied. Data are presented in mean values. Results: The strengths were in the dimensions: supported self-care (6.1 ± 2.7), organization of health care (5.5 ± 2.1), and design of the service delivery system (5.1 ± 2.6). The weaknesses were: clinical information system (3.9 ± 2.7), community resources (4.0 ± 2.9), integration of the components of the care model (4.1 ± 2.7), and support for decisions (4.4 ± 2.9). Conclusion: According to the ACIC, the institutions presented a basic capacity to provide care to hypertensive patients.

Objetivo: evaluar la capacidad institucional para la atención de hipertensos en los servicios de salud del anciano, a partir de la percepción de los equipos de salud. Método: estudio transversal, con 53 profesionales de la salud de instituciones ambulatorias especializadas en el cuidado de ancianos en la ciudad de Manaus, Amazonas, Brasil. Se aplicó la Evaluación de la Capacidad Institucional para la Atención de Condiciones Crónicas (ACIC). Los datos se presentan como valores medios. Resultados: las potencialidades estuvieron en las dimensiones: autocuidado apoyado (6,1 ± 2,7), organización de la atención en salud (5,5 ± 2,1) y diseño del sistema de prestación de servicios (5,1 ± 2,6). Las debilidades fueron: sistema de información clínica (3,9 ± 2,7), recursos comunitarios (4,0 ± 2,9), integración de los componentes del modelo de atención (4,1 ± 2,7) y apoyo a las decisiones (4,4 ± 2,9). Conclusión: según la ACIC, las instituciones tenían una capacidad básica para brindar atención a los pacientes hipertensos.

Ecological risk assessment (ERA) based on contaminated groundwater to predict potential impacts to a wetland ecosystem.

To assess the ecological risk resulting from an accidental gasoline spill upstream from a wetland, groundwater and sediment sampling was carried out during two campaigns at the 48th and 52nd months after the spill had occurred. In total, 21 groundwater monitoring wells in the affected area were sampled plus an additional reference well located upstream from the accident location. Seven sediment sampling points were selected inside the wetland, plus a reference point upstream from the accident. Physicochemical parameters, BTEX (benzene, toluene, ethylbenzene, m-xylene, p-xylene and o-xylene) and metal concentrations were analysed to estimate the chemical risk. Acute (Allivibrio fischeri, Daphnia similis, Hyalella azteca) and chronic (Artemia salina and Desmodesmus subspicatus) toxicity assays were performed with groundwater and sediments elutriate to determine the ecotoxicological risk. Results from groundwater indicated an extreme chemical level of risk in14 out of 21 monitoring wells. These 14 wells also exhibited free-phase gasoline and lead (Pb) concentrations above the threshold values adopted by this study. The presence of Pb, however, could not be associated with the gasoline accident. High acute and chronic toxicities were reported for the majority of wells. Conversely, the risks associated with the sediments were considered low in most sampling points, and the ecotoxicity found could not be related to the presence of gasoline. Groundwater flow modelling results have evidenced the migration of the contamination plume towards the wetland. Thus, to prevent contamination from reaching the protected area, more effective groundwater clean-up techniques are still required.

Intradermal Application of Crotamine Induces Inflammatory and Immunological Changes In Vivo.

Crotamine is a single-chain polypeptide with cell-penetrating properties, which is considered a promising molecule for clinical use. Nevertheless, its biosafety data are still scarce. Herein, we assessed the in vivo proinflammatory properties of crotamine, including its local effect and systemic serum parameters. Sixty male Wistar rats were intradermically injected with 200, 400 and 800 µg crotamine and analyzed after 1, 3 and 7 days. Local effect of crotamine was assessed by determination of MPO and NAG activities, NO levels and angiogenesis. Systemic inflammatory response was assessed by determination of IL-10, TNF-α, CRP, NO, TBARS and SH groups. Crotamine induced macrophages and neutrophils chemotaxis as evidenced by the upregulation of both NAG (0.5⁻0.6 OD/mg) and MPO (0.1⁻0.2 OD/mg) activities, on the first and third day of analysis, respectively. High levels of NO were observed for all concentrations and time-points. Moreover, 800 µg crotamine resulted in serum NO (64.7 µM) and local tissue NO (58.5 µM) levels higher or equivalent to those recorded for their respective histamine controls (55.7 µM and 59.0 µM). Crotamine also induced a significant angiogenic response compared to histamine. Systemically, crotamine induced a progressive increase in serum CRP levels up to the third day of analysis (22.4⁻45.8 mg/mL), which was significantly greater than control values. Crotamine (400 µg) also caused an increase in serum TNF-α, in the first day of analysis (1095.4 pg/mL), however a significant increase in IL-10 (122.2 pg/mL) was also recorded for the same time-point, suggesting the induction of an anti-inflammatory effect. Finally, crotamine changed the systemic redox state by inducing gradual increase in serum levels of TBARS (1.0⁻1.8 µM/mL) and decrease in SH levels (124.7⁻19.5 µM/mL) throughout the experimental period of analysis. In summary, rats intradermally injected with crotamine presented local and systemic acute inflammatory responses similarly to histamine, which limits crotamine therapeutic use on its original form.

Environmental risk assessment of psychoactive drugs in the aquatic environment.

The consumption of psychoactive pharmaceuticals has increased worldwide, and wastewater treatment plants are not able to eliminate them from the effluent. An extensive review was carried out to assess the environmental risk (ERA model) based on secondary data about potential impacts on non-target organisms of seven psychoactive drugs consumed worldwide (alprazolam, bromazepam, citalopram, clonazepam, diazepam, lorazepam, and oxazepam). Risk quotients (RQs) were calculated according to the European Medicines Agency (EMA) on ERA of Medicinal Products For Human Use based on (i) the predicted and measured environmental concentrations (PEC and MEC, respectively) of the psychoactive drug in surface water, groundwater, and wastewater effluent and (ii) the predicted no-effect concentration (PNEC) derived from ecotoxicological assays or ECOSAR software. Furthermore, this study reviews and discusses non-standardized ecotoxicity assays, such as sublethal and behavioral effects on different organisms. In total, 903 MEC entries of psychoactive drugs and 162 data on ecotoxicological assays were gathered from the literature survey addressing behavioral effects (115), acute/chronic effects (35), and sublethal effects (12). Citalopram and diazepam were the only substances that are likely to pose an environmental risk (RQ > 1) to surface waters. Even though there is considerable amount of data on behavioral effects of psychoactive drugs to aquatic species, results are currently not integrated into the EMA risk assessment framework. The large amount of data on psychoactive drug concentrations and effects on non-target organisms collected, interpreted, and discussed in the present study should be used as a baseline for future improvement of ERA strategies.

Vitamin E and caloric restriction promote hepatic homeostasis through expression of connexin 26, N-cad, E-cad and cholesterol metabolism genes.

Connexins (Cx) and cadherins are responsible for cell homeostasis. The Cx activity is directly related to cholesterol. The present work investigates whether vitamin E, with or without caloric restriction (CR), alters the mRNA expression of Cx26, Cx32, Cx43, N-cadherins (N-cads), E-cadherins (E-cads) and alpha-smooth muscle actin (α-SMA), and evaluates their relation to cholesterol metabolism in rat liver. Animals were divided into different groups: control with ad libitum diet (C), control+vitamin E (CV), aloric restriction with intake to 60% of group C (CR), and the intake of group CR+vitamin E (RV). There were increases of manganese superoxide dismutase (Mn-SOD) and glutathione S-transferase mu 1, indicating antioxidant effects of CR and vitamin E. An increase of nitric oxide in the CR group was in agreement with the Mn-SOD data. Supplementation with vitamin E, with or without CR, upregulated the expression of Cx26 mRNA and increased low-density lipoprotein cholesterol (LDL-c) in the CV group. Reductions of Cx32 and Cx43 were associated with lower LDL-c. Increases in Hmgcr and low-density lipoprotein receptor (LDLr) in the CV and RV groups could be explained by the effect of vitamin E. A reduction of LDLr in the CR group was due to the reduced dietary intake. Increases in cadherins in the CV, CR and RV groups were indicative of tissue maintenance, which was also supported by increases of α-SMA in groups CV and RV. Finally, vitamin E, with or without CR, increased Cx26, probably modulated by expression of the Hmgcr and LDLr genes. This suggests important relationship of Cxs and cholesterol metabolism genes.