Extremely cold and hot temperatures increase the risk of ischaemic heart disease mortality: epidemiological evidence from China.

OBJECTIVE: To examine the effects of extremely cold and hot temperatures on ischaemic heart disease (IHD) mortality in five cities (Beijing, Tianjin, Shanghai, Wuhan and Guangzhou) in China; and to examine the time relationships between cold and hot temperatures and IHD mortality for each city. DESIGN: A negative binomial regression model combined with a distributed lag non-linear model was used to examine city-specific temperature effects on IHD mortality up to 20 lag days. A meta-analysis was used to pool the cold effects and hot effects across the five cities. PATIENTS: 16 559 IHD deaths were monitored by a sentinel surveillance system in five cities during 2004-2008. RESULTS: The relationships between temperature and IHD mortality were non-linear in all five cities. The minimum-mortality temperatures in northern cities were lower than in southern cities. In Beijing, Tianjin and Guangzhou, the effects of extremely cold temperatures were delayed, while Shanghai and Wuhan had immediate cold effects. The effects of extremely hot temperatures appeared immediately in all the cities except Wuhan. Meta-analysis showed that IHD mortality increased 48% at the 1st percentile of temperature (extremely cold temperature) compared with the 10th percentile, while IHD mortality increased 18% at the 99th percentile of temperature (extremely hot temperature) compared with the 90th percentile. CONCLUSIONS: Results indicate that both extremely cold and hot temperatures increase IHD mortality in China. Each city has its characteristics of heat effects on IHD mortality. The policy for response to climate change should consider local climate-IHD mortality relationships

Toxicidade de misturas de cianotoxinas e compostos químicos

Mestrado em Biologia Aplicada - Toxicologia e EcotoxicologiaOs organismos aquáticos podem estar constantemente expostos a cianotoxinas e contaminantes antropogénicos provenientes das florescências de cianobactérias e das atividades humanas, respetivamente. A microcistina-LR (MC-LR) e a cilindrospermopsina (CYN) são as cianotoxinas mais frequentemente detetadas nas florescências de cianobactérias e têm sido encontradas simultaneamente na água. Os metais e pesticidas são contaminantes antropogénicos normalmente encontrados no ambiente aquático como resultado da intensificação das atividades agrícolas e industriais. O cádmio (Cd) e a terbutilazina (TBA) foram selecionados como exemplos de metais e pesticidas que podem co-ocorrer com cianotoxinas no ambiente. No entanto, o risco ecotoxicológico combinado de cianotoxinas e/ou contaminantes antropogénicos existentes no ambiente aquático é ainda pouco conhecido. O presente trabalho teve como objetivo identificar alguns padrões e comportamentos biológicos relativamente a este tipo de combinações. Os efeitos de misturas binárias de MC-LR, CYN, Cd e TBA foram avaliados nas taxas de crescimento da alga Chlorella vulgaris após 4 e 7 dias de exposição, usando o modelo de referência de ação independente (AI). A ferramenta MIXTOX foi usada para avaliar possíveis desvios ao modelo de referência (devido a interações entre compostos), tais como sinergismo/antagonismo, dependência da dose ou do rácio da mistura. Os resultados demonstraram vários padrões de resposta, dependendo da mistura binária testada. Foi detetado sinergismo na mistura de MC-LR e CYN em ambos os períodos de exposição. Na mistura de MC-LR e TBA, houve um desvio dependente do nível da dose entre os componentes para ambos os períodos de exposição, onde se observou antagonismo e sinergismo para concentrações baixas e elevadas de ambos os compostos, respetivamente. Na mistura de MC-LR e Cd, registou-se antagonismo após 4 dias de exposição e um desvio dependente do nível da dose entre os componentes após 7 dias de exposição, observando-se sinergismo e antagonismo para concentrações baixas e elevadas de ambos os compostos, respetivamente. Embora na mistura de CYN e TBA se tenha observado um desvio dependente do rácio entre os componentes, com um padrão de antagonismo perante a dominância da CYN, na mistura de CYN e Cd observou-se antagonismo após 4 dias de exposição. Após 7 dias de exposição foi observado um padrão semelhante de resposta em ambas as misturas contendo CYN, ou seja, um desvio dependente do nível da dose entre os componentes na qual se observou sinergismo para as concentrações baixas e antagonismo para as concentrações elevadas testadas de ambos os compostos. Para a mistura de TBA e Cd, registou-se antagonismo após 4 dias de exposição e um desvio dependente do nível das doses entre os componentes (antagonismo para concentrações baixas e sinergismo para concentrações elevadas de ambos os componentes) após 7 dias de exposição. Devido à diversidade de efeitos e comportamentos que podem resultar da combinação de tóxicos bastante comuns, este estudo mostra a importância de avaliar os efeitos combinados de cianotoxinas e/ou contaminantes antropogénicos.Aquatic organisms may be exposed to cyanotoxins and anthropogenic contaminants originated from harmful cyanobacterial blooms and human activities, respectively. Microcystin-LR (MC-LR) and cylindrospermopsin (CYN) are the most frequently detected cyanotoxins in harmful cyanobacterial blooms and have been simultaneously reported in the water. Metals and pesticides are anthropogenic contaminants commonly found in the aquatic environment as a result of the intensification of agricultural and industrial activities. Cadmium (Cd) and terbuthylazine (TBA) were chosen as an example of the possible metals and pesticides that can co-occurr with cyanotoxins in the environment. However, the ecotoxicological risk of combinations of cyanotoxins and/or anthropogenic contaminants in the aquatic environment needs more studies. The present work aimed to elucidate some biological behaviours and patterns regarding these combinations. The effects of binary mixtures of MC-LR, CYN, Cd and TBA on the growth rate of the freshwater algae Chlorella vulgaris were assessed after 4 and 7 days of exposure using the reference model of independent action (IA). The MIXTOX tool was used to detect possible deviations (due to the interaction between compounds) from the reference model such as synergism/antagonism, dose ratio and dose level dependency. The results demonstrated that several patterns of response were obtained depending on the binary mixture. Synergism was detected in the mixture of MC-LR and CYN for the two exposure periods. In the MC-LR and TBA mixture, a dose-level deviation was observed for the two exposure periods indicating antagonism at low dose levels and synergism at high dose levels. In the MC-LR and Cd mixture, deviations for antagonism were found for a 4-day exposure period while a dose-level deviation was observed for a 7-day exposure period showing synergism at low dose levels and antagonism at high dose levels. A dose-ratio deviation was observed in the CYN and TBA mixture, with a pattern for antagonism when CYN was the compound dominant, while deviations for antagonism were observed in the CYN and Cd mixture for a 4-day exposure period. Similar patterns of response were obtained for both mixtures involving CYN after 7 days of exposure, namely dose-level deviation indicating synergism at low dose levels and antagonism at high dose levels. For TBA and Cd mixture, antagonism was found for a 4-day exposure period and a dose-level deviation (antagonism at low dose levels and synergism at high dose levels) was observed for a 7-day exposure period. Due to the diversity of effects and behaviours that can result from the combination of very common toxicants, this study shows the importance of evaluating the combined effects of cyanotoxins and/or anthropogenic contaminants

Fungal Pigments 2021

New edition of the reprint Fungal pigments: Chapters titles: PART 1. Investigation on various chemical classes of fungal pigments: Genomic Analysis and Assessment of Melanin Synthesis in Amorphotheca resinae by Jeong-Joo Oh et al.; Fungal Melanins and Applications in Healthcare, Bioremediation and Industry by Ellie Rose Mattoon et al.; Recent Findings in Azaphilone Pigments by Lúcia P. S. Pimenta et al.; Characterization of a Biofilm Bioreactor Designed for the Single-Step Production of Aerial Conidia and Oosporein by Beauveria bassiana PQ2 by Héctor Raziel Lara-Juache et al.; PART 2. Molecular characterization: Molecular Characterization of Fungal Pigments by Miriam S. Valenzuela-Gloria et al.; PART 3. Biological properties: Seven New Cytotoxic and Antimicrobial Xanthoquinodins from Jugulospora vestita by Lulu Shao et al.; PART 4. Toxicity assessment and safety evaluation of fungal pigments: Safety Evaluation of Fungal Pigments for Food Applications by Rajendran Poorniammal et al.; Preliminary Examination of the Toxicity of Spalting Fungal Pigments: A Comparison between Extraction Methods by Badria H. Almurshidi et al.; PART 5. Use of by-products or waste for industrial production of fungal pigments: Production of Bio-Based Pigments from Food Processing Industry By-Products Using Aspergillus carbonarius by Ezgi Bezirhan Arikan et al.; PART 6. Prospective aspects and brainstorming: Does Structural Color Exist in True Fungi? by Juliet Brodie et al.; Fungal Biomarkers Stability in Mars Regolith Analogues after Simulated Space and Mars-like Conditions by Alessia Cassaro et al

The influences of spatially variable rainfall and localized infiltration on groundwater recharge in a water management context

Water management involves monitoring, predicting, and stewarding the quality and quantity of groundwater recharge at the watershed scale. Recharge sustains baseflow to streams and replenishes water extracted by pumping at wells; it is frequently estimated using numerical models that couple or fully integrate surface water and groundwater domains and use water budgets to partition water into various components of the hydrological cycle. However, uncertainty associated with the input data for large components such as precipitation and evapotranspiration may hinder model accuracy, and preferential flow dynamics such as depression focused recharge (DFR) may not be represented at typical modelling scales (≥10s of sq. km) or with typical approaches. The present study addressed two themes related to groundwater sustainability and vulnerability: 1) the sensitivity of modelled recharge estimates to the spatial variability of rainfall, and 2) the vulnerability of public supply wells to DFR during large-magnitude rainfall or snowmelt events. The region investigated during this research was the Alder Creek watershed (78 sq. km), a typical southern Ontario setting overlying glacial moraine sediments with mostly agricultural land use, some urban and aggregate resource development, and whose recharge supplies multiple municipal well fields for the cities of Kitchener and Waterloo. Rainfall is often the largest component of the water budget and even a small uncertainty percentage may lead to challenges for accurately estimating groundwater recharge as a calculated residual within a water budget approach. However, rainfall monitoring networks typically have widely spaced gauges that are frequently outside the watershed of interest. Assessment of the influence of spatially variable rainfall on annual recharge rate estimates was performed by comparing transient simulations using input data from three different rain gauge networks within a coupled and fully-distributed numerical model. A local network of six weather stations with rain gauges was installed and operated in and around the study watershed for three years, and data from six regional stations (within 30 km of the watershed) and one national station (3 km from the watershed) were obtained from publicly available sources. Time series of distributed, daily rainfall were interpolated via the inverse distance squared method using data from each of the rain gauge networks for three calendar years. The temporal and spatial snowfall distribution was consistent among all scenarios, to maintain focus on differences caused by the rainfall input data. Results showed that annual average recharge rates could differ considerably between scenarios, with differences sometimes greater than the water-budget derived uncertainty for recharge. Differences in overall recharge between pairs of scenarios involving the local rain gauge network were largest, varying by up to 141 mm per year, or 44% of the steady state recharge estimated in a previous study. Streamflow estimates for the local rainfall simulations were closer to observations than those using regional or national rainfall. Because the three scenarios used the same set of underlying soil parameters, the results suggest that the availability of local rainfall measurements has the potential to improve the calibration of transient watershed hydrogeological models. The second theme of the present study was exemplified by the Walkerton tragedy in 2000, where pathogenic microbes were rapidly transported from ground surface to a public supply well during a heavy rainfall event. The vulnerability of such wells to surface-originating contaminants during major hydrological events remains poorly understood and is difficult to quantify. Such events may result in overland flow collecting in low topographic locations, leading to localized infiltration. If focused recharge occurs in the immediate vicinity of a public supply well, the threat to the water quality of that well may significantly increase temporarily. These conditions are frequently encountered within the glaciated landscape of southern Ontario. Conventional approaches for defining the threat of groundwater under the direct influence of surface water (GUDI) do not routinely account for this type of transient infiltration event and instead assume steady state flow fields without localized recharge. The present study combined the monitoring and modelling of a site in southern Ontario where DFR is routinely observed to occur within 50 m of a public supply well. Extensive site characterization and hydrologic monitoring were conducted at the site over a period of 3.5 years, specifically during large-magnitude hydrologic events including heavy rainfall and snowmelt. Integrated surface water – groundwater models employing HydroGeoSphere (HGS) were used to quantify the transport of potential contaminants infiltrating beneath a depression and a creek and the associated risk to the public supply well. Simulated relative concentrations at the well were below “detection” for typical median contaminant concentrations in surface water but > 1 cfu/100 mL with travel times between 118 and 142 days for creek and DFR solutes, respectively, based on maximum initial surface water concentrations. Results suggest that DFR and localized recharge could increase the threat to overburden wells under extreme conditions. Ponding reduced travel time by at least 58 days for the DFR solute. In order to extend the analysis of recharge estimate sensitivity to spatial rainfall variability to the longer term, and to incorporate the influence of actual evapotranspiration (AET) uncertainty, a method was developed to employ stochastic rainfall time series and AET estimates in a Monte Carlo framework to quantify the resulting variability in recharge estimates and three groundwater management metrics. Stochastic rainfall time series were generated via a parametric, mixed exponential method for three virtual stations within the Alder Creek watershed and constrained by field-derived spatial correlation coefficients. Observed snowfall data from one nearby national weather station were used to calculate total precipitation. Stochastic annual AET estimates were generated based on: 1) calculated annual potential evapotranspiration at the national weather station, 2) observed variation about the Budyko curve in 45 US MOPEX watersheds with PET/P ratios within ±0.05 of the average ratio calculated for the national weather station near the watershed, and 3) a correction factor to remove AET from the saturated zone. Recharge rates for the Alder Creek watershed were calculated via a 46-year vadose zone water budget for each of 16,778 realizations. The surface water fraction of streamflow was estimated using hydrograph separation results for the watershed. It was hypothesized that spatially variable precipitation would exert more influence on recharge than AET because it is a larger component of the local water budget. Groundwater recharge results were applied to three different metrics related to water quality, well vulnerability, and water quantity. Results suggest that estimates of non-point source contaminant loadings to the water table could differ by up to ±14% from the average. Worst case changes in capture zone area estimates for a public supply well could be up to ±15% different from the average. The ratio of maximum to minimum cumulative recharge over all realizations was 1.31, though contributions from spatial rainfall variability alone led to a ratio of 1.15. This suggests that AET uncertainty and spatial rainfall variability each contribute nearly the same amount of variability to recharge estimates. This latter ratio is less than the result (~2) from a previous study of a much larger watershed in Spain. The results highlight the importance of AET estimates for recharge rate estimation, and their potential impacts on land use planning and groundwater management. This method could be used to project impacts of climate change on recharge variability at the watershed scale. Overall, results suggest that the spatial variability of rainfall could impact recharge rate estimates in numerical models of small to medium sized watersheds (e.g., 78 sq. km), especially during short simulations. Annual recharge estimates could vary over a range equivalent to 44% of a previously estimated steady state value, though long-term (46-yr) estimates could vary over a range equivalent to 12% of this value due to averaging over time. Non-point source loadings and capture zone areas could vary up to ±7.0% and ±7.4% from the average, respectively, over the long term due to spatial rainfall variability, though uncertainties associated with AET could increase this to ±14% or ±15%, respectively. The hydrological event characterization and well vulnerability modelling of the second research theme suggest that localized recharge could lead to increased microbial risks for wells screened in overburden sediments during large hydrological events (≥ 40 mm rainfall over 4 days) through the phenomenon of temporary ponding. The method developed for the long-term stochastic recharge rate analysis could be applied in other settings as an alternative to, or to complement, large-scale, fully-distributed 3D numerical modelling

Studies on Water Management Issues

This book shares knowledge gained through water management related research. It describes a broad range of approaches and technologies, of which have been developed and used by researchers for managing water resource problems. This multidisciplinary book covers water management issues under surface water management, groundwater management, water quality management, and water resource planning management subtopics. The main objective of this book is to enable a better understanding of these perspectives relating to water management practices. This book is expected to be useful to researchers, policy-makers, and non-governmental organizations working on water related projects in countries worldwide