Biocides in Soils of Urban Stormwater Infiltration Systems—Indications of Inputs from Point and Non-point Sources

International audienceAbstract Urban stormwater contains various micropollutants, such as biocides, which are washed off from facades during wind-driven rain events. Biocides can reach the groundwater via stormwater infiltration systems (SIS), although the soil layer acts as a reactive barrier preventing the leaching of biocides but producing transformation products (TPs). Little is known about the occurrence and concentration of biocides in SIS soils, their distribution and temporal behavior. Here, we present a first systematic screening of three commonly used biocides (diuron, octylisothiazolinone (OIT), terbutryn) and four TPs of terbutryn in 46 French and German SIS. Overall, biocide occurrence in SIS topsoils was ubiquitous but low, while point source inputs to specific SIS were high but rare. Low concentrations ( 90 days) and widely used in renders and paints. In contrast, high concentrations of diuron (168 ng g -1 ) and OIT (58 ng g -1 ) were observed in only one sample, suggesting an urban point source contamination, possibly from a freshly repainted facade. The distinction between source types provides a basis for targeted measures to prevent biocide entry to groundwater. Altogether, this study opens the door to a more systematic consideration of micropollutant dissipation and ecotoxicological effects in SIS design and monitoring

Discharge and fate of biocide residuals to ephemeral stormwater retention pond sediments

Biocides used in paints and renders prevent algae and fungi growth but can wash off during wind-driven rain and enter urban environments. Retention ponds represent part of stormwater management that retain water and partly pollutants. However, it is poorly understood which percentage of biocides leached from facades reaches a pond and how efficiently biocides are retained inside ponds although biocides can have harmful environmental effects. Here, we combined measurements and modeling to address diffuse biocide loss and a pond's retention capacity in a delimited residential area of 3 ha, with detached houses connected to an ephemeral retention pond. Six stormwater events were sampled within 2 years and confirmed biocidal residuals at pond inflow. Model results revealed that during the sampled events only 11% of terbutryn leachate arrived at the pond while the major part of this biocide was diffusely lost in the residential area. Measured low terbutryn concentrations in the sediment (mean 2.6 ng g−1) confirmed this result. Model results suggested that approximately 50% of terbutryn reaching the pond were retained and degraded. Our results are site-specific but suggest that biocide retention in ponds is limited, environmental entry pathways are diverse and that biocide use should be limited at its source. HIGHLIGHTS Comparison of measured and modeled data suggests that diffuse losses are the major pathway (89%) of biocides.; Only 11% of leached terbutryn arrived at the stormwater retention pond where about half was retained while the remaining half spilled over into the sewage system.; Results imply diverse entry pathways of biocides and suggest measures at the source are best.

Where should hydrology go? An early-career perspective on the next IAHS Scientific Decade: 2023-2032

This paper shares an early-career perspective on potential themes for the upcoming International Association of Hydrological Sciences (IAHS) scientific decade (SD). This opinion paper synthesizes six discussion sessions in western Europe identifying three themes that all offer a different perspective on the hydrological threats the world faces and could serve to direct the broader hydrological community: “Tipping points and thresholds in hydrology”, “Intensification of the water cycle”, and “Water services under pressure”. Additionally, four trends were distinguished concerning the way in which hydrological research is conducted: big data, bridging science and practice, open science, and inter- and multidisciplinarity. These themes and trends will provide valuable input for future discussions on the theme for the next IAHS SD. We encourage other Early-Career Scientists to voice their opinion by organizing their own discussion sessions and commenting on this paper to make this initiative grow from a regional initiative to a global movement

Where should hydrology go? An early-career perspective on the next IAHS Scientific Decade: 2023–2032

This paper shares an early-career perspective on potential themes for the upcoming International Association of Hydrological Sciences (IAHS) Scientific Decade (SD). This opinion paper synthesizes six discussion sessions in western Europe identifying three themes that all offer a different perspective on the hydrological threats the world faces and could serve to direct the broader hydrological community: “Tipping points and thresholds in hydrology,” “Intensification of the water cycle,” and “Water services under pressure.” Additionally, four trends were distinguished concerning the way in which hydrological research is conducted: big data, bridging science and practice, open science, and inter- and multidisciplinarity. These themes and trends will provide valuable input for future discussions on the theme for the next IAHS SD. We encourage other early-career scientists to voice their opinion by organizing their own discussion sessions and commenting on this paper to make this initiative grow from a regional initiative to a global movement

Oxidative stress induces myeloperoxidase expression in endocardial endothelial cells from patients with chronic heart failure.

Increased oxidative stress has been implicated in the pathogenesis of a number of cardiovascular diseases. Recent findings suggest that myeloperoxidase (MPO) may play a key role in the initiation and maintenance of chronic heart failure (CHF) by contributing to the depletion of the intracellular reservoir of nitric oxide (NO). NO consumption through MPO activity may lead to protein chlorination or nitration, leading to tissue damage. Primary cultures of human endocardial endothelial cells (EEC) obtained at heart transplantation of patients with CHF and human umbilical vein endothelial cells (HUVEC) were subjected to oxidative stress by incubation with hydrogen peroxide at non lethal (60 microM) dose for different exposure times (3 and 6 h). Treated and control cells were tested by immunohistochemistry and RT-PCR for MPO and 3-chlorotyrosine expression. Both endothelial cell types expressed myeloperoxidase following oxidative stress, with higher levels in EEC. Moreover, 3-chlorotyrosine accumulation in treated cells alone indicated the presence of MPO-derived hypochlorous acid. Immunohistochemistry on sections from post-infarcted heart confirmed in vivo the endothelial positivity to MPO, 3-chlorotyrosine and, to a minor extent, nitrotyrosine. Immunohistochemical observations were confirmed by detection of MPO mRNA in both stimulated EEC and HUVEC cells. This study demonstrates for the first time that EEC can express MPO after oxidative stress, both in vitro and in vivo, followed by accumulation of 3-chlorotyrosine, an end product of oxidative stress. Deregulation of endothelial functions may contribute to the development of a number of cardiovascular diseases, including CHF. The results also highlight the notion that endothelium is not only a target but also a key player in oxidative-driven cardiovascular stress