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    Challenges of managing harmful algal blooms in US drinking water systems

    1.Hudnell, H. K. The state of US freshwater harmful algal blooms assessments, policy and legislation. Toxicon 55, 1024–1034 (2010).CAS 
    Article 

    Google Scholar 
    2.Hudnell, H. K. & Dortch, Q. in Cyanobacterial Harmful Algal Blooms: State of the Science and Research Needs (ed. Hudnell, H. K.) 17–43 (Springer, 2008).3.Loftin, K. A. et al. Cyanotoxins in inland lakes of the United States: occurrence and potential recreational health risks in the EPA National Lakes Assessment 2007. Harmful Algae 56, 77–90 (2016).CAS 
    Article 

    Google Scholar 
    4.Dodds, W. K. et al. Eutrophication of US freshwaters: analysis of potential economic damages. Environ. Sci. Technol. 43, 12–19 (2009).CAS 
    Article 

    Google Scholar 
    5.Jetoo, S., Grover, V. I. & Krantzberg, G. The Toledo drinking water advisory: suggested application of the water safety planning approach. Sustainability 7, 9787–9808 (2015).Article 

    Google Scholar 
    6.Water Advisory After-Action Assessment (Novak Consulting Group, 2018).7.Milly, P. C. D. et al. Stationarity is dead: whither water management? Science 319, 573–574 (2008).CAS 
    Article 

    Google Scholar 
    8.Hallegatte, S. Strategies to adapt to an uncertain climate change. Glob. Environ. Change 19, 240–247 (2009).Article 

    Google Scholar 
    9.A Compilation of Cost Data Associated with the Impacts and Control of Nutrient Pollution EPA 820-F-15-096 (EPA, 2015).10.Brooks, B. W. et al. Are harmful algal blooms becoming the greatest inland water quality threat to public health and aquatic ecosystems? Environ. Toxicol. Chem. 35, 6–13 (2016).CAS 
    Article 

    Google Scholar 
    11.He, X. et al. Toxic cyanobacteria and drinking water: impacts, detection, and treatment. Harmful Algae 54, 174–193 (2016).CAS 
    Article 

    Google Scholar 
    12.Recommendations for Public Water Systems to Manage Cyanotoxins in Drinking Water EPA 815-R-15-010 (EPA, 2015).13.Zamyadi, A. et al. Toxic cyanobacterial breakthrough and accumulation in a drinking water plant: a monitoring and treatment challenge. Water Res. 46, 1511–1523 (2012).CAS 
    Article 

    Google Scholar 
    14.Walker, B. & Wathen, E. Across US, Toxic Blooms Pollute Lakes (EWG, 2018); https://www.ewg.org/toxicalgalblooms/15.Carmichael, W. W. & Boyer, G. L. Health impacts from cyanobacteria harmful algae blooms: implications for the North American Great Lakes. Harmful Algae 54, 194–212 (2016).Article 

    Google Scholar 
    16.Davis, T. W., Berry, D. L., Boyer, G. L. & Gobler, C. J. The effects of temperature and nutrients on the growth and dynamics of toxic and non-toxic strains of Microcystis during cyanobacteria blooms. Harmful Algae 8, 715–725 (2009).CAS 
    Article 

    Google Scholar 
    17.Ho, J. C. & Michalak, A. M. Challenges in tracking harmful algal blooms: a synthesis of evidence from Lake Erie. J. Great Lakes Res. 41, 317–325 (2015).Article 

    Google Scholar 
    18.Paerl, H. W. & Paul, V. J. Climate change: links to global expansion of harmful cyanobacteria. Water Res. 46, 1349–1363 (2012).CAS 
    Article 

    Google Scholar 
    19.Chapra, S. C. et al. Climate change impacts on harmful algal blooms in US freshwaters: a screening-level assessment. Environ. Sci. Technol. 51, 8933–8943 (2017).CAS 
    Article 

    Google Scholar 
    20.Paerl, H. W. & Huisman, J. Climate change: a catalyst for global expansion of harmful cyanobacterial blooms. Environ. Microbiol. Rep. 1, 27–37 (2009).CAS 
    Article 

    Google Scholar 
    21.Mullin, C. A. & Kirchhoff, C. J. Marshaling adaptive capacities within an adaptive management framework to enhance the resiliency of wastewater systems. J. Am. Water Resour. Assoc. 55, 906–919 (2019).Article 

    Google Scholar 
    22.Henrie, T., Plummer, S. & Roberson, J. A. Occurrence and state approaches for addressing cyanotoxins in US drinking water. J. Am. Water Works Assoc. 109, 40–47 (2017).Article 

    Google Scholar 
    23.EPA drinking water health advisories for cyanotoxins. EPA https://www.epa.gov/cyanohabs/epa-drinking-water-health-advisories-cyanotoxins (accessed 25 April 2021).24.Watson, S. B. et al. in Freshwater Algae of North America: Ecology and Classification (eds Wehr, J. D. et al.) 873–920 (Academic Press, 2015); https://doi.org/10.1016/B978-0-12-385876-4.00020-725.Moore, S. K. et al. Impacts of climate variability and future climate change on harmful algal blooms and human health. Environ. Health 7, S4 (2008).Article 

    Google Scholar 
    26.Anderson, D. M., Glibert, P. M. & Burkholder, J. M. Harmful algal blooms and eutrophication: nutrient sources, composition, and consequences. Estuaries 25, 704–726 (2002).Article 

    Google Scholar 
    27.Olson, G., Wilczak, A., Boozarpour, M., Degraca, A. & Weintraub, J. M. Evaluating and prioritizing contaminants of emerging concern in drinking water. J. Am. Water Works Assoc. 109, 54–63 (2017).Article 

    Google Scholar 
    28.The Fourth Unregulated Contaminant Monitoring Rule (UCMR 4): Data Summary, April 2021 (EPA, 2021).29.Beversdorf, L. J. et al. Analysis of cyanobacterial metabolites in surface and raw drinking waters reveals more than microcystin. Water Res. 140, 280–290 (2018).CAS 
    Article 

    Google Scholar 
    30.Almuhtaram, H., Cui, Y., Zamyadi, A. & Hofmann, R. Cyanotoxins and cyanobacteria cell accumulations in drinking water treatment plants with a low risk of bloom formation at the source. Toxins 10, 430 (2018).CAS 
    Article 

    Google Scholar 
    31.Wolf, D. & Klaiber, H. A. Bloom and bust: toxic algae’s impact on nearby property values. Ecol. Econ. 135, 209–221 (2017).Article 

    Google Scholar 
    32.Smith, E. A., Blanchard, P. B. & Bargu, S. Education and public outreach concerning freshwater harmful algal blooms in southern Louisiana. Harmful Algae 35, 38–45 (2014).Article 

    Google Scholar 
    33.Brisson, G., Dubé, K., Doyon, S. & Lévesque, B. Social construction of cyanobacteria blooms in Quebec: a matter of perceptions and risk management. Sage Open 7, 1–10 (2017).Article 

    Google Scholar 
    34.Zhang, W. & Sohngen, B. Do US anglers care about harmful algal blooms? A discrete choice experiment of Lake Erie recreational anglers. Am. J. Agric. Econ. 100, 868–888 (2018).Article 

    Google Scholar 
    35.McCarty, C. L. et al. Community needs assessment after microcystin toxin contamination of a municipal water supply—Lucas County, Ohio, September 2014. Morb. Mortal Wkly Rep. 65, 925–929 (2016).Article 

    Google Scholar 
    36.Wilson, R. S., Howard, G. & Burnett, E. A. Improving nutrient management practices in agriculture: the role of risk-based beliefs in understanding farmers’ attitudes toward taking additional action. Water Resour. Res. 5, 6735–6746 (2014).Article 

    Google Scholar 
    37.Renn, O. The social amplification/attenuation of risk framework: application to climate change. Wiley Interdiscip. Rev. Clim. Change 2, 154–169 (2011).Article 

    Google Scholar 
    38.Breakwell, G. M. Models of risk construction: some applications to climate change. Wiley Interdiscip. Rev. Clim. Change 1, 857–870 (2010).Article 

    Google Scholar 
    39.Kirchhoff, C. J. & Watson, P. L. Are wastewater systems adapting to climate change? J. Am. Water Resour. Assoc. 55, 869–880 (2019).Article 

    Google Scholar 
    40.Bubeck, P., Botzen, W. J. W. & Aerts, J. A review of risk perceptions and other factors that influence flood mitigation behavior. Risk Anal. 32, 1481–1495 (2012).CAS 
    Article 

    Google Scholar 
    41.Soane, E. et al. Flood perception and mitigation: the role of severity, agency, and experience in the purchase of flood protection, and the communication of flood information. Environ. Plan. A 42, 3023–3038 (2010).Article 

    Google Scholar 
    42.Wachinger, G., Renn, O., Begg, C. & Kuhlicke, C. The risk perception paradox—implications for governance and communication of natural hazards. Risk Anal. 33, 1049–1065 (2013).Article 

    Google Scholar 
    43.Dittrich, R., Wreford, A., Butler, A. & Moran, D. The impact of flood action groups on the uptake of flood management measures. Climatic Change 138, 471–489 (2016).Article 

    Google Scholar 
    44.Pahl-Wostl, C. An evolutionary perspective on water governance: from understanding to transformation. Water Resour. Manag. 31, 2917–2932 (2017).Article 

    Google Scholar 
    45.Dilling, L., Daly, M. E., Travis, W. R., Wilhelmi, O. V. & Klein, R. A. The dynamics of vulnerability: why adapting to climate variability will not always prepare us for climate change. Wiley Interdiscip. Rev. Clim. Change 6, 413–425 (2015).Article 

    Google Scholar 
    46.Coastal SEES: Lake Erie. Notes from October 26 workshop titled The Future of Harmful Algal Blooms held at Ottawa National Wildlife Refuge (2018).47.Gerding, J. A. et al. Uncovering environmental health: an initial assessment of the profession’s health department workforce and practice. J. Environ. Health 81, 24–33 (2019).
    Google Scholar 
    48.Bazerman, M. H. Climate change as a predictable surprise. Climatic Change 77, 179–193 (2006).Article 

    Google Scholar 
    49.Bolson, J., Martinez, C., Breuer, N., Srivastava, P. & Knox, P. Climate information use among southeast US water managers: beyond barriers and toward opportunities. Reg. Environ. Change 13, 141–151 (2013).Article 

    Google Scholar 
    50.Kirchhoff, C. J. Understanding and enhancing climate information use in water management. Climatic Change 119, 495–509 (2013).Article 

    Google Scholar 
    51.Lemos, M. C., Kirchhoff, C. J. & Ramprasad, V. Narrowing the climate information usability gap. Nat. Clim. Change 2, 789–794 (2012).Article 

    Google Scholar 
    52.Dillman, D. A., Smyth, J. D. & Christian, L. M. Internet, Phone, Mail, and Mixed-Mode Surveys: The Tailored Design Method (Wiley, 2014).53.Tourangeau, R. & Plewes, T. J. Nonresponse in Social Science Surveys: A Research Agenda (National Academic Press, 2013); https://doi.org/10.17226/1829354.Sánchez-Fernández, J., Muñoz-Leiva, F. & Montoro-Ríos, F. J. Improving retention rate and response quality in Web-based surveys. Comput. Human Behav. 28, 507–514 (2012).Article 

    Google Scholar 
    55.Hollister, J. W. & Kreakie, B. J. Associations between chlorophyll a and various microcystin health advisory concentrations. F1000Res. 5, 151 (2016).
    Google Scholar 
    56.RStudio Team RStudio: Integrated Development for R (RStudio, PBC, 2019).57.Fox, J. & Weisberg, S. An R Companion to Applied Regression (Sage, 2019). More

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    Collaborative management of the Grand Ethiopian Renaissance Dam increases economic benefits and resilience

    Structure of the modeling frameworkThe coevolutionary macroeconomy and river system simulation framework introduced in this study consists of two modeling components: (a) the Egyptian economy and (b) the Nile river system. The modeling framework accounts for the coevolutionary dynamics of river and economic systems using an iterative process. This multi-sector framework is designed for river systems with multiyear storage dams and a mix of hydro and non-hydro electricity generation. The two modeling components are described separately below, followed by a description of their interaction, which characterizes two-way hydro-economic feedbacks. The application of the coevolutionary framework to the Nile is then discussed.Economy-wide modeling componentThe Egyptian economy-wide modeling component is based on the IFPRI (International Food Policy Research Institute) standard open-source CGE model43. The model was modified to include water, energy, and land components and run dynamically (i.e., for a multiyear period). In previous studies, water, energy, and land resources have been included in the productive activities of CGE models in a variety of ways. A recent review of the literature distinguished between CGE models that treat water as an explicit factor of production, those that include water as an implicit factor of production (i.e., embedded in land productivity), and those that treat water as a commodity (i.e., an intermediate input)58. Energy-oriented CGE models typically combine energy with capital in the production structure of goods and services59,60. The inclusion of energy in CGE models is straightforward compared to water because energy is a marketed commodity that can be easily reallocated to different sectors. The reallocation of water supplies across space and time requires storage and network infrastructure and is often constrained by unpredictable supplies (stochastic hydrology). Moreover, raw water supplies are typically unpriced61,62,63,64; thus, the economic value of water is not included in economic data (e.g., social accounting matrices and input–output tables).In this study, we modified IFPRI’s standard CGE model such that economic activities produce commodities using a three-level process (Supplementary Fig. 5). At the top level, composite intermediate inputs and the value-added-energy bundle are combined to produce commodities using a Leontief Function65. The function maintains fixed proportions of inputs (composite intermediate inputs and value-added energy in this case) for each unit of output (commodity). At the second level, energy and value-added are aggregated using a Constant Elasticity of Substitution function (CES)66, such that the optimal input quantities of value-added and energy for each activity are determined based on relative prices subject to substitution elasticity similar to energy-oriented CGE models59. At the third level, substitution is allowed between the electricity commodity and other energy commodities using a CES function. A CES function is also used to combine labor, capital, and land into value-added.The model is customized to allow each household group to allocate its consumption budget to the purchase of commodities based on a nested linear expenditure system (LES)67 and CES (Supplementary Fig. 5). At the top level, a LES function is used to divide the consumption budget between essential and nonessential demands68. The nonessential consumption budget is divided between five commodity categories using fixed shares. Each category includes different commodities that can substitute each other based on CES functions.We modified the IFPRI CGE model to include four types of capital: (a) hydro capital used by a hydropower activity to produce electricity, (b) non-hydro capital used by a non-hydro activity to produce electricity, (c) water capital used by a municipal water activity to produce municipal water, and (d) general capital used by other activities. The use of land and water capital varies endogenously based on their rents. Logistic functions are used to simulate the response of the use of land and water capital to their rents. General and non-hydro capital grow based on past investments. Investment is allocated between these two capital types according to their relative rates of return. Given the increase in electricity demand resulting from economic growth, this specification of investment behavior allows for an incremental expansion of non-hydro electricity generation capacity; hydropower capacity does not grow endogenously with the year-to-year investment allocation. It is assumed that no new hydropower investments are made over the 30-year simulation period. To connect the economy-wide model with the river system model, dynamic exogenous shocks on land, water capital, hydro capital, and non-hydro capital are introduced to the economic model based on the river system modeling component, which simulates water and electricity availability, as explained below.River system modeling componentPywr, a generic open-source Python library for simulating resource system networks42, is used to model the water system, including hydropower generation, in addition to an aggregated representation of non-hydro electricity generation. Pywr allows building resource system elements using input (e.g., catchments), output (e.g., water abstraction), and storage nodes (e.g., reservoirs). Nodes are linked in a network fashion to enable the flow and allocation of resources such as water and electricity. Pywr uses a time-stepping linear programming approach to drive resource allocation using priorities and system operating rules. Any time step resolution can be selected for Pywr simulations (e.g., hourly, daily, weekly, and monthly). Pywr’s multi-scenario simulation allows consideration of uncertainty in resource systems, e.g., hydrologic stochasticity.The simulation results of Pywr can be processed, observed, and/or saved through “recorders.” We extended Pywr “recorders” to enable annual aggregation of the water and electricity metrics required for integration with the economy-wide modeling component. These metrics include annual irrigation and municipal water supply fractions, annual electricity generation from hydropower dams, and annual electricity generation from non-hydro energy generators.Coevolutionary macroeconomy and river system simulationSupplementary Fig. 6 shows a flowchart of the novel coevolutionary macroeconomy and river system generalized hydro-economic69 modeling framework. The figure shows the interaction between the economy-wide modeling component (with an annual time step) and the river system modeling component (with a monthly time step) within each annual time step. Dynamic-recursive multiyear simulations are performed by repeating the procedure in Supplementary Fig. 6 multiple times.The dynamic behavior of CGE models is typically driven by external drivers, such as capital growth (determined as a function of previous investment levels), labor growth, and productivity trends. In the first iteration, the CGE model solves based on its external drivers and determines changes to annual water and electricity demands and non-hydro electricity generation capacity relative to the economy’s initial year. Changes produced by the CGE model in relation to the irrigated area, the water capital, the demand for the electricity commodity, and the non-hydro capital are used as an estimate in the river system model for changes in irrigation water demand, municipal water demand, electricity demand, and non-hydro electricity generation capacity, respectively. The first CGE iteration assumes no irrigation deficit and electricity generation equal to that of the base year. The CGE and the river system models iteratively correct the initial assumptions of water curtailments and electricity generation, as explained in more detail below.CGE models typically have an annual time step, but river system models run at smaller time intervals (e.g., monthly, weekly, daily, hourly). River system models have finer temporal resolutions to enable simulation of the spatial and temporal constraints of river basin resource systems, i.e., to better capture the consequences of stochastic hydrology and infrastructure constraints (e.g., reservoir storage). Although the iterative framework presented in Supplementary Fig. 6 is based on a monthly river system model, models with smaller time steps could also be used. The river system model uses the changes in irrigation water demand, municipal water demand, electricity demand, and non-hydro electricity generation capacity, computed by the economy-wide modeling component, to scale the corresponding water and electricity parameters. The river system model then performs a monthly simulation over a 12-month period based on monthly river flow data and the modified water and electricity demands and non-hydro capacity. The river system model then computes the fractions of annual irrigation and municipal water demands that can be met in addition to the annual hydro and non-hydro electricity generation. Water supply and electricity generation depend on the spatial and temporal availability of natural resources (e.g., river flow), infrastructure capacities (e.g., non-hydro and hydro capacities), and infrastructure operating rules.After the river system modeling component determines water supply fractions and electricity generation, two tests are performed to determine (a) whether the models have converged and (b) when to stop iterating. These tests indicate whether to proceed to the next iteration or accept the current state of the CGE and the river system models as a solution for the annual time step. Passing either of the two tests terminates the iterative convergence process. The CGE and the river system models pass the convergence test when the difference between the current and the previous iteration’s values of an annual economy, water, or energy metric falls below a certain convergence threshold. The value of the threshold depends on the desired level of accuracy and available computational capacity. The stopping test imposes a maximum number of iterations at which the current state of the CGE and the river system models is considered a solution for the annual time step. The stopping test acts as a safeguard to prevent excessively long iteration over one annual time step. The convergence test is performed starting from the second iteration. Thus, at least two iterations are performed within each annual time step to ensure convergence.Failure in the convergence and stopping tests results in proceeding to the next iteration. In the next iteration, annual water supply fractions and electricity generation of the previous iteration are applied to the CGE model to compute new changes to annual water and electricity demands and non-hydro electricity generation capacity relative to the initial year of the economy (i.e., the base year). The irrigation and municipal water supply fractions, computed by the river system modeling component, are introduced to the CGE model as shocks to the land and water capital, respectively. The ratio between current electricity generation and electricity generation in the initial year of the economy is calculated for each of the two electricity generation technology groups (i.e., hydro and non-hydro) and introduced as shocks to the hydro and non-hydro capitals.Implementation of the coevolutionary frameworkThe open-source Python Network Simulation (Pynsim) framework44 was extended and used to integrate the economy-wide and river system modeling components and to manage their iteration, sequencing, and time stepping. Each of the two components was specified as a Pynsim “engine”44. Although the IFPRI CGE model is written in the General Algebraic Modeling System (GAMS)70, it was linked to Pynsim through the GAMS Python Application Programming Interface. Eight Pynsim integration nodes were created for data exchange between the economy-wide and river system modeling components. Four of the integration nodes transfer changes in annual water (irrigation and municipal) and electricity demands and non-hydro electricity generation capacity from the economy-wide to the river system modeling components. The other four integration nodes transfer the annual water (irrigation and municipal) supply fractions and hydro and non-hydro electricity generation from the river system to the economy-wide modeling components.Eastern Nile River system modelSupplementary Fig. 7 shows a schematic of the monthly river system model of the Eastern Nile Basin. The model uses naturalized inflow data for the period 1901–2002, obtained from the Eastern Nile Technical Regional Office54. The Eastern Nile River System model contains all major dams and water consumers in the basin, including the GERD and the HAD. The baseline water withdrawal targets are shown in Supplementary Fig. 8. Supplementary Table 1 reports the main characteristics of the dams included in the Nile River System model. The model was calibrated and validated at eight locations across the basin based on historically observed river flows and reservoir water levels over 1970–2002. This period was chosen based on the availability of observed data. Supplementary Fig. 9 and Supplementary Table 2 show the performance of the Eastern Nile River system at eight locations. In the model, non-hydro electricity generation is used to fill the gap between hydropower generation and electricity demand, subject to generation capacity. This assumption is valid since hydropower in Egypt is a by-product of other activities. Furthermore, the historical evolution of the Egyptian electricity mix shows relatively regular annual hydropower generation with a steady increase in electricity generation from other technologies to fill the supply-demand gap8.Initial filling assumptions of the Washington draft proposalSupplementary Table 3 describes the 5-year plan for the initial filling of the GERD in the Washington draft proposal assuming normal or above-average hydrological conditions. We assumed that after achieving the water retention target of the first year (4.9 bcm), two 375 MW turbines become operational. The rest of the turbines become operational after achieving the second year’s water retention target (18.4 bcm). We assumed that once the filling targets of year-1 or year-2 are achieved, reservoir storage is always maintained above these targets in order to keep the turbines operational. In the Washington draft proposal, water retention is limited to July and August, with a minimum environmental release of 43 Mm3/day. During the initial filling period, from September to June, releases from the GERD equal the inflow to the reservoir. However, if a drought occurs during the 5-year initial filling plan specified in Table S3, the Washington draft proposal has provisions for implementing delays in filling the GERD (our assumptions for these provisions are described in a later section).Long-term operation assumptions of the Washington draft proposalThe Washington draft proposal’s operating rules for the long-term operation of the GERD begins when reservoir storage reaches 49.3 bcm. We assumed that when reservoir storage is at or above 49.3 bcm, water is released through the GERD’s turbines to maintain a constant monthly energy production of 1170 GWh to maximize the 90% power generation reliability71. If reservoir storage drops below 49.3 bcm, the target monthly energy production is reduced to 585 GWh. The purpose of reducing the energy generation target is to enable the GERD storage to recover above 49.3 bcm. Water releases designed to maintain a regular power rate depend on the reservoir water level at the beginning of the time step (the higher the water level, the lower the releases required). A minimum environmental release of 43 Mm3/day is maintained throughout the year when possible. Additional water releases may be made following drought mitigation mechanisms that resemble those of the Washington draft proposal, as described below.Drought mitigation assumptions of the Washington draft proposalThe Washington plan includes three mechanisms to mitigate the adverse effects of droughts, prolonged droughts, and prolonged periods of dry years on the downstream riparians46. The mechanism for mitigating droughts is triggered when the GERD’s annual inflow is forecast to be ≤37 bcm. This first mechanism requires Ethiopia to release a minimum annual water volume, depending on the forecast annual inflow and GERD storage at the beginning of the hydrologic year (see Exhibit A in Egypt’s letter to the United Nations Security Council dated 19 June 202046).The effectiveness of the mechanism for mitigating droughts depends on the accuracy of the forecast of the annual inflow for the upcoming hydrological year. To implement the Washington plan in this study’s river simulation model, we do not forecast annual flows for the next hydrological year. Instead, drought mitigation conditions are checked in March of every hydrologic year, by which time, on average, about 96% of the river’s annual flow is already known because it occurs from June to February. If necessary, water releases during the remaining 3 months of the hydrological year (March–May) are increased to achieve the minimum annual releases specified in the mechanism for mitigating droughts. These increased releases during March–May effectively offset any deviations from water releases specified by the drought mitigation mechanism given the dam inflows and releases in the previous 9 months of the current hydrologic year.The mechanism for mitigating prolonged droughts requires that the average annual release over every 4-year period equal at least 39 bcm (37 bcm during the initial filling). In the implementation of this prolonged drought mitigation mechanism of the Washington draft proposal in our river simulation model, we check in March of every hydrological year to ensure that this annual average release over the previous 4-year period is achieved. Although this mechanism does not depend on reservoir inflow, it is also checked for in March to provide flexibility to GERD operation during the rest of the year.The mechanism for mitigating prolonged periods of dry years is similar to the prolonged drought mitigation mechanism, except the period over which annual releases are averaged is longer (5 years) and the average annual release is higher (40 bcm). We implement this mechanism in our river simulation model in the same way, checking in March of every hydrological year to ensure that the annual average release over the previous 5-year period is achieved. Supplementary Fig. 10 shows the exceedance probability of the annual, 4-year average annual, and 5-year average annual flow of Blue Nile at the location of the GERD over the period 1901–2002. The drought mitigation thresholds of the Washington draft proposal are marked in the figure to show their probability of occurrence in the river flow data.If a deficit from the minimum releases of any of the three mechanisms is identified at the beginning of March, water releases over March–May are increased equally in each month to offset the deficit.Initial filling assumptions of the coordinated operationThe coordinated operating strategy for the initial filling of the GERD is similar to the Washington plan, except for the retention of inflows to meet the targets in Table S3 is not constrained to July and August. The coordinated operation requires that a minimum environmental release of 43 Mm3/day be maintained throughout the year when possible. If physically possible, releases from the GERD are also greater than or equal to (1) Sudan’s monthly water withdrawal targets along the Blue and Main Nile, plus (2) Egypt’s monthly water release target from the HAD if HAD storage is below 50 bcm (156 m a.s.l.). This operating strategy enables Ethiopia to avoid delays in filling the GERD as long as HAD storage is at or above 50 bcm. In simulating coordinated operation, the operations of the Roseires, Sennar, and Merowe dams have been adapted to pass GERD releases intended to benefit Egypt. It was assumed that two of the GERD turbines become operational after achieving the first year’s water retention target, and the rest of the turbines become operational once the second year’s filling target is achieved. After achieving the filling targets of year-1 or year-2, reservoir storage is always maintained above these targets (i.e., 4.9 or 18.4 bcm) to keep the turbines operational.Long-term operation assumptions of the coordinated operationAs with the Washington draft proposal, the long-term operation of the GERD begins as soon as reservoir storage reaches 49.3 bcm. Also the same as the Washington plan, it was assumed that when reservoir storage is at or above 49.3 bcm, water is released through the GERD’s turbines to maintain a constant monthly energy production of 1170 GWh to maximize the 90% power generation reliability71. If reservoir storage drops below 49.3 bcm, the target monthly energy generation is reduced to 585 GWh. A minimum environmental release of 43 Mm3/day is maintained throughout the year when physically possible. The key difference between the Washington draft proposal and coordinated operation is that when physically possible, the coordinated operation ensures that the GERD releases are greater than or equal to Sudan’s water withdrawal targets on the Blue and Main Nile plus Egypt’s target releases from the HAD if HAD storage is below 50 bcm (156 m asl). This provides Ethiopia more flexibility in the operation of the GERD as long as HAD storage is at or above 50 bcm.Drought mitigation assumptions of the coordinated operationThe coordinated operation strategy does not include drought mitigation measures that are based on minimum annual water releases. Instead, a dynamic mechanism is used to help reduce downstream water deficits during periods of water scarcity, as explained in previous sections. Such an approach provides flexibility to Ethiopia in GERD operation and increases the basin-wide and national water, electricity, and economic gains.Economy-wide model of EgyptThe CGE model of Egypt represents a dynamic-recursive, single-country, open-economy, including four agent types: households, enterprises, the government, and the rest of the world. Households are classified into ten groups based on location (urban or rural) and income (five quintiles). The model includes 11 production activities: agriculture, light industry, heavy industry, construction, transport, hydropower, non-hydro, other energy, municipal water supply, public services, and other services. Each of the 11 activities produces a distinct commodity except hydropower and non-hydro, which produce a similar commodity (i.e., electricity). Production activities use six factors of production to produce commodities: labor, land, general capital, water capital, hydro capital, and non-hydro capital. Labor and general capital are assumed to be mobile across production activities, whereas land, water capital, hydro capital, and non-hydro capital are specific to agriculture, municipal water supply, hydropower, and non-hydro, respectively. Labor is updated exogenously to follow the projected changes in the 16–64 age group of the shared socioeconomic pathways (SSPs) “middle of the road” scenario72. Total factor productivity is also updated exogenously to follow economic performance under the “middle of the road” scenario.The CGE model of Egypt assumes fixed price of commodities on the international market following the small open-economy assumption, i.e., that the economy participates in international trade but does not affect world prices73. Government spending is simulated as a fixed share of total absorption (total demand for marketed goods and services). The model follows the saving-investment identity (savings are equal to investment) assuming fixed saving propensities. Foreign savings are assumed fixed, and the exchange rate is flexible.The baseline model was calibrated to a 2019 Social Accounting Matrix (SAM) of Egypt. The 2019 SAM was generated based on a 2011 SAM using an expansion factor equal to the ratio between the Egyptian GDP in the 2 years. We compared the generated SAM with the structure of Egypt’s economy based on the most recent data in the World Bank Database; no significant differences were found in the economy’s structure. Supplementary Fig. 11 shows this comparison.Nile River system–Egypt’s economic integrationThe Eastern Nile River system model and the CGE model of Egypt run dynamically over a 30-year simulation period (2020–2049) and multiple scenarios. For each 30-year simulation, the CGE model executes 30 annual time steps, and the river system model executes 360 monthly time steps (30 years × 12 months). The CGE and river system models are integrated through the water and electricity sectors, as described earlier. The convergence test is performed using the GDP at market prices with an assumed convergence threshold of US$ 5 million. A maximum of 50 iterations is specified for each annual time step. All simulated time steps converged in More

  • in

    Water is the middle child in global climate policy

    1.Fawcett, A. A. et al. Science 350, 1168–1169 (2015).CAS 
    Article 

    Google Scholar 
    2.Griscom, B. W. et al. Proc. Natl Acad. Sci. USA 114, 11645–11650 (2017).CAS 
    Article 

    Google Scholar 
    3.Santos da Silva, S. R. et al. Nat. Commun. 12, 1276 (2021).CAS 
    Article 

    Google Scholar 
    4.Santos da Silva, S. R. et al. PLoS ONE 14, e0215013 (2019).CAS 
    Article 

    Google Scholar 
    5.Muñoz Castillo, R. et al. J. Clean. Prod. 214, 52–61 (2019).Article 

    Google Scholar 
    6.Hejazi, M. I. et al. Proc. Natl Acad. Sci. USA 112, 10635–10640 (2015).CAS 
    Article 

    Google Scholar 
    7.Vörösmarty, C. J., Green, P., Salisbury, J. & Lammers, R. B. Science 289, 284–288 (2000).Article 

    Google Scholar 
    8.Kiguchi, M., Shen, Y., Kanae, S. & Oki, T. Hydrol. Sci. J. 60, 14–29 (2015).Article 

    Google Scholar 
    9.Graham, N. T. et al. Water Resour. Res. 54, 6423–6440 (2018).Article 

    Google Scholar 
    10.O’Neill, B. C. et al. Glob. Environ. Change 42, 169–180 (2017).Article 

    Google Scholar 
    11.Graham, N. T. et al. Environ. Res. Lett. 15, 014007 (2020).Article 

    Google Scholar 
    12.Rodriguez, D. J. et al. Modeling the Water–Energy Nexus: How Do Water Constraints Affect Energy Planning in South Africa? (World Bank Group, 2017).13.Rodriguez, D. J. et al. Thirsty Energy: Modeling the Water–Energy Nexus in China (World Bank Group, 2018).14.Borgomeo, E. et al. The Water–Energy–Food Nexus in the Middle East and North Africa: Scenarios for a Sustainable Future (World Bank Group, 2018). More

  • in

    Climate change and the future of western US water governance

    1.Goble, D. D. Or. L. Rev. 71, 381–408 (1992).
    Google Scholar 
    2.Goldberg, C. E., Tsosie, R., Clinton, R. N. & Riley, A. R. American Indian Law: Native Nations and the Federal System 7th edn (Carolina Academic Press, 2015).3.Winters v. United States, 207 U.S. 564 (1908).4.In Re The General Adjudication of All Rights to Use Water in the Big Horn River System, 753 P.2d 76 (WY, 1988).5.Arizona v. California, 373 U.S 546 (1963).6.Water Policies for the Future (National Water Commission, 1973).7.Neuman, J. C. Envtl L. Rev. 28, 919–996 (1998).
    Google Scholar 
    8.Tarlock, A. D. & Robison, J. A. Law of Water Rights and Resources (Thomson Reuters, 2019).9.State Ex. Re. Reynolds v. Mears 525 P.2d 870 (NM, 1974).10.National Audubon Society v. Superior Court 658 P.2d 788 (CA, 1983).11.Hedden-Nicely, D. R. Idaho L. Rev. 47, 147–173 (2010).
    Google Scholar 
    12.Wilkinson, C. F. Crossing the Next Meridian: Land, Water, and the Future of the West (Island Press, 1992).13.Fiege, M. Irrigated Eden: The Making of an Agricultural Landscape in the American West (Univ. Washington Press, 1999).14.Reisner, M. Cadillac Desert: The American West and its Disappearing Water (Penguin, 1993).15.Ebeling, E., Kearl, Z., Weaver, E. & Wentzel, N. Water Banking and Water Marketing in Select Western States (Washington State Department of Ecology, 2019).16.Colorado River Water Delivery Agreement: Federal Quantification Settlement Agreement for Purposes of Section 5(B) of Interim Surplus Guidelines (US Department of the Interior, 2003).17.Surface Water Coalition – Idaho Ground Water Appropriators, Inc. 2015 Settlement Agreement (2015).18.Keeler, B. L., Derickson, K. D., Waters, H. & Walker, R. One Earth 2, 211–213 (2020).Article 

    Google Scholar 
    19.Norton-Smith, K. et al. Climate Chand Indigenous Peoples: A Synthesis of Current Impacts and Experiences Report PNW-GTR-944 (United States Forest Service, 2016).20.Climate Change and Indigenous Peoples: Indigenous Peoples and Indigenous Voices: Backgrounder (UN Permanent Forum on Indigenous Issues, 2007). More

  • in

    Towards a model for road runoff infiltration management

    1.Leroy, M. C. et al. Assessment of PAH dissipation processes in large-scale outdoor mesocosms simulating vegetated road-side swales. Sci. Total Environ. 520, 146–153 (2015).CAS 
    Article 

    Google Scholar 
    2.Helmreich, B., Hilliges, R., Schriewer, A. & Horn, H. Runoff pollutants of a highly trafficked urban road – correlation analysis and seasonal influences. Chemosphere 80, 991–997 (2010).CAS 
    Article 

    Google Scholar 
    3.Wagner, S. et al. Tire wear particles in the aquatic environment – A review on generation, analysis, occurrence, fate and effects. Water Res. 139, 83–100 (2018).CAS 
    Article 

    Google Scholar 
    4.Pramanik, B. K., Roychand, R., Monira, S., Bhuiyan, M. & Jegatheesan, V. Fate of road-dust associated microplastics and per- and polyfluorinated substances in stormwater. Process Saf. Environ. Prot. 144, 236–241 (2020).CAS 
    Article 

    Google Scholar 
    5.Hensen, B. et al. Entry of biocides and their transformation products into groundwater via urban stormwater infiltration systems. Water Res. 144, 413–423 (2018).CAS 
    Article 

    Google Scholar 
    6.Mrowiec, M. Road runoff management using improved infiltration ponds. Transp. Res. Procedia 14, 2659–2667 (2016).Article 

    Google Scholar 
    7.Goh, X., Radhakrishnan, M., Zevenbergen, C. & Pathirana, A. Effectiveness of Runoff control legislation and active, beautiful, clean (ABC) waters design features in Singapore. Water 9, 627 (2017).Article 

    Google Scholar 
    8.Liu, A., Liu, L., Li, D. & Guan, Y. Characterizing heavy metal build-up on urban road surfaces: Implication for stormwater reuse. Sci. Total Environ. 515–516, 20–29 (2015).Article 
    CAS 

    Google Scholar 
    9.Chen, C., Guo, W. & Ngo, H. H. Pesticides in stormwater runoff—a mini review. Front. Environ Sci. Eng. 13, 72 (2019).Article 
    CAS 

    Google Scholar 
    10.Leroy, M. C. et al. Performance of vegetated swales for improving road runoff quality in a moderate traffic urban area. Sci. Total Environ. 566–567, 113–121 (2016).Article 
    CAS 

    Google Scholar 
    11.Weiss, P. T., LeFevre, G. & Gulliver, J. S. Contamination of Soil and Groundwater due to Stormwater Infiltration Practices. Saint Anthony Falls Laboratory Project Report No. 38 (Saint Anthony Falls Laboratory, 2008).12.Cederkvist, K., Jensen, M. B. & Holm, P. E. Method for assessment of stormwater treatment facilities – synthetic road runoff addition including micro-pollutants and tracer. J. Environ. Manag. 198, 107–117 (2017).CAS 
    Article 

    Google Scholar 
    13.Tedoldi, D., Chebbo, G., Pierlot, D., Kovacs, Y. & Gromaire, M. C. Impact of runoff infiltration on contaminant accumulation and transport in the soil/filter media of Sustainable Urban Drainage Systems: a literature review. Sci. Total Environ. 569–570, 904–926 (2016).Article 
    CAS 

    Google Scholar 
    14.Murakami, M. et al. Multiple evaluations of the removal of pollutants in road runoff by soil infiltration. Water Res. 42, 2745–2755 (2008).CAS 
    Article 

    Google Scholar 
    15.Flanagan, K. et al. Retention and transport processes of particulate and dissolved micropollutants in stormwater biofilters treating road runoff. Sci. Total Environ. 656, 1178–1190 (2019).CAS 
    Article 

    Google Scholar 
    16.Piguet, P., Parriaux, A. & Bensimon, M. The diffuse infiltration of road runoff: An environmental improvement. Sci. Total Environ. 397, 13–23 (2008).CAS 
    Article 

    Google Scholar 
    17.Scholz, M. & Kazemi Yazdi, S. Treatment of road runoff by a combined storm water treatment, detention and infiltration system. Water Air Soil Pollut. 198, 55–64 (2009).CAS 
    Article 

    Google Scholar 
    18.Huber, M. & Helmreich, B. Stormwater management: calculation of traffic area runoff loads and traffic related emissions. Water 8, 294 (2016).19.Krein, A. & Schorer, M. Road runoff pollution by polycyclic aromatic hydrocarbons and its contribution to river sediments. Water Res. 34, 4110–4115 (2000).CAS 
    Article 

    Google Scholar 
    20.Murakami, M., Nakajima, F. & Furumai, H. Modelling of runoff behaviour of particle-bound polycyclic aromatic hydrocarbons (PAHs) from roads and roofs. Water Res. 38, 4475–4483 (2004).CAS 
    Article 

    Google Scholar 
    21.Pinasseau, L. et al. Use of passive sampling and high resolution mass spectrometry using a suspect screening approach to characterise emerging pollutants in contaminated groundwater and runoff. Sci. Total Environ. 672, 253–263 (2019).CAS 
    Article 

    Google Scholar 
    22.Bergé, A. et al. Non-target strategies by HRMS to evaluate fluidized micro-grain activated carbon as a tertiary treatment of wastewater. Chemosphere 213, 587–595 (2018).Article 
    CAS 

    Google Scholar 
    23.Nguyen, T. M. H. et al. Influences of chemical properties, soil properties, and solution ph on soil-water partitioning coefficients of per- and polyfluoroalkyl substances (PFASs). Environ. Sci. Technol. 54, 15883–15892 (2020).CAS 
    Article 

    Google Scholar 
    24.Batjes, N. H. Methodological Framework for Assessment and Mapping of the Vulnerability of Soils to Diffuse Pollution at a Continental Level (SOVEUR Project) (ISRIC—World Soil Information, 1997).25.Arrêté du 8 janvier 1998 fixant les prescriptions techniques applicables aux épandages de boues sur les sols agricoles pris en application du décret no. 97-1133 du 8 décembre 1997 relatif à l’épandage des boues issues du traitement des eaux usées. J. Off. 16, https://www.legifrance.gouv.fr/loda/id/JORFTEXT000000570287/ (1998).26.Sauvé, S., Hendershot, W. & Allen, H. E. Solid-solution partitioning of metals in contaminated soils: dependence on pH, total metal burden and organic matter. Environ. Sci. Technol. 34, 1125–1131 (2000).Article 
    CAS 

    Google Scholar 
    27.Yadav, S. Correlation analysis in biological studies. J. Pract. Cardiovasc. Sci. 4, 116 (2018).Article 

    Google Scholar 
    28.Cottin, N. & Merlin, G. Removal of PAHs from laboratory columns simulating the humus upper layer of vertical flow constructed wetlands. Chemosphere 73, 711–716 (2008).CAS 
    Article 

    Google Scholar 
    29.Ren, X. et al. Sorption, transport and biodegradation – an insight into bioavailability of persistent organic pollutants in soil. Sci. Total Environ. 610–611, 1154–1163 (2018).Article 
    CAS 

    Google Scholar 
    30.Wiest, L. et al. Priority substances in accumulated sediments in a stormwater detention basin from an industrial area. Environ. Pollut. 243, 1669–1678 (2018).CAS 
    Article 

    Google Scholar 
    31.Hares, R. J. & Ward, N. I. Sediment accumulation in newly constructed vegetative treatment facilities along a new major road. Sci. Total Environ. 334–335, 473–479 (2004).Article 
    CAS 

    Google Scholar 
    32.Strömvall, A., Norin, M. & Pettersson, T. J. R. Organic contaminants in urban sediments and vertical leaching in road ditches. In The Eighth Highway and Urban Environment Symposium (eds Morrison, G. M. & Rauch, S.) 235–247 (Springer, 2007).33.Dechesne, M., Barraud, S. & Bardin, J. P. Spatial distribution of pollution in an urban stormwater infiltration basin. J. Contam. Hydrol. 72, 189–205 (2004).CAS 
    Article 

    Google Scholar 
    34.Dierkes, C. & Geiger, W. F. Pollution retention capabilities of roadside soils. Water Sci. Technol. 39, 201–208 (1999).CAS 
    Article 

    Google Scholar 
    35.Sauvé, S., Mcbride, M. B., Norvell, W. A. & Hendershot, W. H. Copper solubility and speciation of in situ contaminated soils: effects of copper level, pH and organic matter. Water Air Soil Pollut. 100, 133–149 (1997).Article 

    Google Scholar 
    36.Sauvé, S., Manna, S., Turmel, M. C., Roy, A. G. & Courchesne, F. Solid-solution partitioning of Cd, Cu, Ni, Pb, and Zn in the organic horizons of a forest soil. Environ. Sci. Technol. 37, 5191–5196 (2003).Article 
    CAS 

    Google Scholar 
    37.El-Mufleh, A. et al. Distribution of PAHs and trace metals in urban stormwater sediments: combination of density fractionation, mineralogy and microanalysis. Environ. Sci. Pollut. Res. 21, 9764–9776 (2014).CAS 
    Article 

    Google Scholar 
    38.Rostvall, A. et al. Removal of pharmaceuticals, perfluoroalkyl substances and other micropollutants from wastewater using lignite, Xylit, sand, granular activated carbon (GAC) and GAC+Polonite® in column tests – role of physicochemical properties. Water Res. 137, 97–106 (2018).CAS 
    Article 

    Google Scholar 
    39.Paredes, L., Fernandez-Fontaina, E., Lema, J. M., Omil, F. & Carballa, M. Understanding the fate of organic micropollutants in sand and granular activated carbon biofiltration systems. Sci. Total Environ. 551–552, 640–648 (2016).Article 
    CAS 

    Google Scholar 
    40.FAO, ITPS, GSBI, SCBD & EC. State of knowledge of soil biodiversity – status, challenges and potentialities. FAO https://doi.org/10.4060/cb1928en (2020).41.Tietz, A., Langergraber, G., Watzinger, A., Haberl, R. & Kirschner, A. K. T. Bacterial carbon utilization in vertical subsurface flow constructed wetlands. Water Res. 42, 1622–1634 (2008).CAS 
    Article 

    Google Scholar 
    42.Weil, R. R. & Brady, N. C. The Nature and Properties of Soils 15th edn (Pearson Education, 2016).43.Usman, K., Al-Ghouti, M. A. & Abu-Dieyeh, M. H. The assessment of cadmium, chromium, copper, and nickel tolerance and bioaccumulation by shrub plant Tetraena qataranse. Sci. Rep. 9, 1–11 (2019).
    Google Scholar 
    44.Nuel, M., Laurent, J., Bois, P., Heintz, D. & Wanko, A. Seasonal and ageing effect on the behaviour of 86 drugs in a full-scale surface treatment wetland: removal efficiencies and distribution in plants and sediments. Sci. Total Environ. 615, 1099–1109 (2018).CAS 
    Article 

    Google Scholar 
    45.FAO. World Reference Base For Soil Resources 2014. International Soil Classification System For Naming Soils And Creating Legends For Soil Maps. World Soil Resources Report No. 106 (2014).46.Villette, C. et al. In situ localization of micropollutants and associated stress response in Populus nigra leaves. Environ. Int. 126, 523–532 (2019).CAS 
    Article 

    Google Scholar 
    47.Schymanski, E. L. et al. Identifying small molecules via high resolution mass spectrometry: communicating confidence. Environ. Sci. Technol. 48, 2097–2098 (2014).CAS 
    Article 

    Google Scholar 
    48.Boleda, M. R., Galceran, M. T. & Ventura, F. Validation and uncertainty estimation of a multiresidue method for pharmaceuticals in surface and treated waters by liquid chromatography-tandem mass spectrometry. J. Chromatogr. A 1286, 146–158 (2013).CAS 
    Article 

    Google Scholar 
    49.Barupal, D. K. & Fiehn, O. Chemical similarity enrichment analysis (ChemRICH) as alternative to biochemical pathway mapping for metabolomic datasets. Sci. Rep. 7, 1–11 (2017).CAS 
    Article 

    Google Scholar  More

  • in

    Reimagining safe drinking water on the basis of twenty-first-century science

    1.Muir, D. C. G. & Howard, P. H. Are there other persistent organic pollutants? A challenge for environmental chemists. Environ. Sci. Technol. 40, 7157–7166 (2006).CAS 
    Article 

    Google Scholar 
    2.Wang, Z., Walker, G. W., Muir, D. C. G. & Nagatani-Yoshida, K. Toward a global understanding of chemical pollution: a first comprehensive analysis of national and regional chemical inventories. Environ. Sci. Technol. 54, 2575–2584 (2020).CAS 
    Article 

    Google Scholar 
    3.Schwarzenbach, R. P. et al. The challenge of micropollutants in aquatic systems. Science 313, 1072–1077 (2006).CAS 
    Article 

    Google Scholar 
    4.National Academy of Sciences Science and Decisions: Advancing Risk Assessment (National Academies, 2009); https://doi.org/10.17226/122095.Paustenbach, D. J., Panko, J. M., Scott, P. K. & Unice, K. M. A methodology for estimating human exposure to perfluorooctanoic acid (PFOA): a retrospective exposure assessment of a community (1951-2003). J. Toxicol. Environ. Health Pt A 70, 28–57 (2007).CAS 
    Article 

    Google Scholar 
    6.Sunderland, E. M. et al. A review of the pathways of human exposure to poly- and perfluoroalkyl substances (PFASs) and present understanding of health effects. J. Expo. Sci. Environ. Epidemiol. 29, 131–147 (2019).CAS 
    Article 

    Google Scholar 
    7.Hopkins, Z. R., Sun, M., DeWitt, J. C. & Knappe, D. R. U. Recently detected drinking water contaminants: GenX and other per- and polyfluoroalkyl ether acids. J. Am. Water Works Assoc. 110, 13–28 (2018).CAS 
    Article 

    Google Scholar 
    8.Jarema, K. A., Hunter, D. L., Shaffer, R. M., Behl, M. & Padilla, S. Acute and developmental behavioral effects of flame retardants and related chemicals in zebrafish. Neurotoxicol. Teratol. 52, 194–209 (2015).CAS 
    Article 

    Google Scholar 
    9.Weis, C. P. The value of alternatives assessment. Environ. Health Perspect. 124, A40 (2016).Article 

    Google Scholar 
    10.Jacobs, M. M., Malloy, T. F., Tickner, J. A. & Edwards, S. Alternatives assessment frameworks: research needs for the informed substitution of hazardous chemicals. Environ. Health Perspect. 124, 265–280 (2016).Article 

    Google Scholar 
    11.Sarigiannis, D. A. & Hansen, U. Considering the cumulative risk of mixtures of chemicals – a challenge for policy makers. Environ. Health 11(Suppl 1), S18 (2012).Article 

    Google Scholar 
    12.Von Gunten, U. Oxidation processes in water treatment: are we on track? Environ. Sci. Technol. 52, 5062–5075 (2018).CAS 
    Article 

    Google Scholar 
    13.Krasner, S. W. et al. Occurrence of a new generation of disinfection byproducts. Environ. Sci. Technol. 40, 7175–7185 (2006).CAS 
    Article 

    Google Scholar 
    14.Richardson, S. D. & Plewa, M. J. To regulate or not to regulate? What to do with more toxic disinfection by-products? J. Environ. Chem. Eng. 8, 103939 (2020).CAS 
    Article 

    Google Scholar 
    15.Altenburger, R. et al. Mixture effects in samples of multiple contaminants—an inter-laboratory study with manifold bioassays. Environ. Int. 114, 95–106 (2018).CAS 
    Article 

    Google Scholar 
    16.Legler, J. et al. A novel in vivo bioassay for (xeno-)estrogens using transgenic zebrafish. Environ. Sci. Technol. 34, 4439–4444 (2000).CAS 
    Article 

    Google Scholar 
    17.Nelson, J., Bishay, F., van Roodselaar, A., Ikonomou, M. & Law, F. C. P. The use of in vitro bioassays to quantify endocrine disrupting chemicals in municipal wastewater treatment plant effluents. Sci. Total Environ. 374, 80–90 (2007).CAS 
    Article 

    Google Scholar 
    18.Stalter, D., Magdeburg, A. & Oehlmann, J. Comparative toxicity assessment of ozone and activated carbon treated sewage effluents using an in vivo test battery. Water Res. 44, 2610–2620 (2010).CAS 
    Article 

    Google Scholar 
    19.Cao, N. et al. Evaluation of wastewater reclamation technologies based on in vitro and in vivo bioassays. Sci. Total Environ. 407, 1588–1597 (2009).CAS 
    Article 

    Google Scholar 
    20.Neale, P. A. et al. Application of in vitro bioassays for water quality monitoring in three drinking water treatment plants using different treatment processes including biological treatment, nanofiltration and ozonation coupled with disinfection. Environ. Sci. Water Res. Technol. 6, 2444–2453 (2020).CAS 
    Article 

    Google Scholar 
    21.Escher, B. I. et al. Benchmarking organic micropollutants in wastewater, recycled water and drinking water with in vitro bioassays. Environ. Sci. Technol. 48, 1940–1956 (2014).CAS 
    Article 

    Google Scholar 
    22.Conley, J. M. et al. Comparison of in vitro estrogenic activity and estrogen concentrations in source and treated waters from 25 U.S. drinking water treatment plants. Sci. Total Environ. 579, 1610–1617 (2017).CAS 
    Article 

    Google Scholar 
    23.Medlock Kakaley, E. et al. In vitro effects-based method and water quality screening model for use in pre- and post-distribution treated waters. Sci. Total Environ. 768, 144750 (2021).CAS 
    Article 

    Google Scholar 
    24.Neale, P. A. & Escher, B. I. In vitro bioassays to assess drinking water quality. Curr. Opin. Environ. Sci. Health 7, 1–7 (2019).Article 

    Google Scholar 
    25.Alygizakis, N. A. et al. Exploring the potential of a global emerging contaminant early warning network through the use of retrospective suspect screening with high-resolution mass spectrometry. Environ. Sci. Technol. 52, 5135–5144 (2018).CAS 
    Article 

    Google Scholar 
    26.Escher, B. I., Stapleton, H. M. & Schymanski, E. L. Tracking complex mixtures in our changing environment. Science 367, 388–392 (2020).CAS 
    Article 

    Google Scholar 
    27.Peter, K. T., Wu, C., Tian, Z. & Kolodziej, E. P. Application of nontarget high resolution mass spectrometry data to quantitative source apportionment. Environ. Sci. Technol. 53, 12257–12268 (2019).CAS 
    Article 

    Google Scholar 
    28.Schymanski, E. L. et al. Non-target screening with high-resolution mass spectrometry: critical review using a collaborative trial on water analysis. Anal. Bioanal. Chem. 407, 6237–6255 (2015).CAS 
    Article 

    Google Scholar 
    29.Williams, A. J. et al. The CompTox chemistry dashboard: a community data resource for environmental chemistry. J. Cheminform. 9, 61 (2017).Article 
    CAS 

    Google Scholar 
    30.CompTox Chemicals Dashboard (US EPA, 2017); https://www.epa.gov/chemical-research/comptox-chemicals-dashboard31.Dong, H., Cuthbertson, A. A. & Richardson, S. D. Effect-directed analysis (eda): a promising tool for nontarget identification of unknown disinfection byproducts in drinking water. Environ. Sci. Technol. 54, 1290–1292 (2020).CAS 
    Article 

    Google Scholar 
    32.Vughs, D., Baken, K. A., Kolkman, A., Martijn, A. J. & de Voogt, P. Application of effect-directed analysis to identify mutagenic nitrogenous disinfection by-products of advanced oxidation drinking water treatment. Environ. Sci. Pollut. Res. 25, 3951–3964 (2018).CAS 
    Article 

    Google Scholar 
    33.Altenburger, R. et al. Future water quality monitoring—adapting tools to deal with mixtures of pollutants in water resource management. Sci. Total Environ. 512–513, 540–551 (2015).Article 
    CAS 

    Google Scholar 
    34.Zwart, N. et al. High-throughput effect-directed analysis using downscaled in vitro reporter gene assays to identify endocrine disruptors in surface water. Environ. Sci. Technol. 52, 4367–4377 (2018).CAS 
    Article 

    Google Scholar 
    35.Brunner, A. M. et al. Integration of target analyses, non-target screening and effect-based monitoring to assess OMP related water quality changes in drinking water treatment. Sci. Total Environ. 705, 135779 (2020).CAS 
    Article 

    Google Scholar 
    36.Raies, A. B. & Bajic, V. B. In silico toxicology: computational methods for the prediction of chemical toxicity. WIREs Comput. Mol. Sci. 6, 147–172 (2016).CAS 
    Article 

    Google Scholar 
    37.New Approach Methods Work Plan (US EPA, 2020).38.Bliss, C. I. The toxicity of poisons applied jointly. Ann. Appl. Biol. 26, 585–615 (1939).CAS 
    Article 

    Google Scholar 
    39.Altenburger, R., Nendza, M. & Schüürmann, G. Mixture toxicity and its modeling by quantitative structure-activity relationships. Environ. Toxicol. Chem. 22, 1900–1915 (2003).CAS 
    Article 

    Google Scholar 
    40.Rider, C. V. & Ellen, J. (eds) Chemical Mixtures and Combined Chemical and Nonchemical Stressors (Springer, 2018); https://doi.org/10.1007/978-3-319-56234-641.Rabinowitz, J. R., Goldsmith, M. R., Little, S. B. & Pasquinelli, M. A. Computational molecular modeling for evaluating the toxicity of environmental chemicals: prioritizing bioassay requirements. Environ. Health Perspect. 116, 573–576 (2008).CAS 
    Article 

    Google Scholar 
    42.Kwiatkowski, C. F. et al. Scientific basis for managing PFAS as a chemical class. Environ. Sci. Technol. Lett. 7, 532–543 (2020).CAS 
    Article 

    Google Scholar 
    43.Rosario-Ortiz, F. et al. How do you like your tap water? Science 351, 912–914 (2006).Article 

    Google Scholar 
    44.Kar, S. & Leszczynski, J. Exploration of computational approaches to predict the toxicity of chemical mixtures. Toxics 7, 15 (2019).CAS 
    Article 

    Google Scholar 
    45.Crittenden, J. C. et al. Predicting GAC performance with rapid small-scale column tests. J. Am. Water Works Assoc. 83, 77–87 (1991).CAS 
    Article 

    Google Scholar 
    46.Topol, E. J. Individualized medicine from prewomb to tomb. Cell 157, 241–253 (2014).CAS 
    Article 

    Google Scholar 
    47.Ternes, T. A. et al. Integrated evaluation concept to assess the efficacy of advanced wastewater treatment processes for the elimination of micropollutants and pathogens. Environ. Sci. Technol. 51, 308–319 (2017).CAS 
    Article 

    Google Scholar 
    48.Leusch, F. D. L. et al. Assessment of wastewater and recycled water quality: a comparison of lines of evidence from in vitro, in vivo and chemical analyses. Water Res. 50, 420–431 (2014).CAS 
    Article 

    Google Scholar 
    49.Drewes, J. E., Hemming, J., Ladenburger, S. J., Schauer, J. & Sonzogni, W. An assessment of endocrine disrupting activity changes during wastewater treatment through the use of bioassays and chemical measurements. Water Environ. Res. 77, 12–23 (2005).CAS 
    Article 

    Google Scholar 
    50.Dingemans, M. M. L., Baken, K. A., van der Oost, R., Schriks, M. & van Wezel, A. P. Risk-based approach in the revised European Union drinking water legislation: opportunities for bioanalytical tools. Integr. Environ. Assess. Manag. 15, 126–134 (2019).Article 

    Google Scholar 
    51.Escher, B. I. & Neale, P. A. Effect-based trigger values for mixtures of chemicals in surface water detected with in vitro bioassays. Environ. Toxicol. Chem. 40, 487–499 (2021).CAS 
    Article 

    Google Scholar 
    52.Reemtsma, T. et al. Mind the gap: persistent and mobile organic compounds—water contaminants that slip through. Environ. Sci. Technol. 50, 10308–10315 (2016).CAS 
    Article 

    Google Scholar 
    53.Brack, W. Effect-directed analysis: a promising tool for the identification of organic toxicants in complex mixtures? Anal. Bioanal. Chem. 377, 397–407 (2003).CAS 
    Article 

    Google Scholar 
    54.Campos, B. & Colbourne, J. K. How omics technologies can enhance chemical safety regulation: perspectives from academia, government, and industry. Environ. Toxicol. Chem. 37, 1252–1259 (2018).CAS 
    Article 

    Google Scholar 
    55.Zhen, H. et al. Assessing the impact of wastewater treatment plant effluent on downstream drinking water-source quality using a zebrafish (Danio Rerio) liver cell-based metabolomics approach. Water Res. 145, 198–209 (2018).CAS 
    Article 

    Google Scholar 
    56.Xia, P. et al. Benchmarking water quality from wastewater to drinking waters using reduced transcriptome of human cells. Environ. Sci. Technol. 51, 9318–9326 (2017).CAS 
    Article 

    Google Scholar 
    57.Prasse, C. Reactivity-directed analysis-a novel approach for the identification of toxic organic electrophiles in drinking water. Environ. Sci. Process. Impacts 23, 48–65 (2021).CAS 
    Article 

    Google Scholar 
    58.Dodd, B. AB-1755 The Open and Transparent Water Data Act: Assembly Bill No. 1755 (California Legislative Information, 2016); https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=201520160AB175559.Mons, B., Schultes, E., Liu, F. & Jacobsen, A. The FAIR principles: first generation implementation choices and challenges. Data Intell. 2, 1–9 (2020).Article 

    Google Scholar 
    60.National Research Council Toward Precision Medicine: Building a Knowledge Network for Biomedical Research and a New Taxonomy of Disease (National Academies, 2011).61.Drinking Water and Public Health in the United States (American Public Health Association, 2019).62.Allman, A., Daoutiis, P., Arnol, W. A. & Cussler, E. L. Efficient water pollution abatement. Ind. Eng. Chem. Res. https://doi.org/10.1021/acs.iecr.9b03241 (2019).63.A Working Approach for Identifying Potential Candidate Chemicals for Prioritization (US EPA, 2018).64.Janesick, A. S. et al. On the utility of ToxCastTM and ToxPi as methods for identifying new obesogens. Environ. Health Perspect. https://doi.org/10.1289/ehp.1510352 (2016).65.Janesick, A. S., Dimastrogiovanni, G., Chamorro-Garcia, R. & Blumberg, B. Reply to “comment on ‘On the utility of ToxCastTM and ToxPi as methods for identifying new obesogens’”. Environ. Health Perspect. https://doi.org/10.1289/EHP1122 (2017).66.Houck, K. A. et al. Comment on “On the utility of ToxCastTM and ToxPi as methods for identifying new obesogens”. Environ. Health Perspect. https://doi.org/10.1289/EHP881 (2017).67.Molnar, C. et al. Pitfalls to avoid when interpreting machine learning models. Preprint at https://arxiv.org/abs/2007.04131 (2020). More

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    Webcast: how to green your lab

    CAREER COLUMN
    25 August 2021

    Webcast: how to green your lab

    Taking steps to lower the environmental impact of your research can reduce costs.

    Jack Leeming

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    Jack Leeming

    Jack Leeming is a careers editor at Nature.

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    In this 60-minute webinar, three speakers share their experiences and advice on how to reduce waste and emissions from the laboratory. They then answer questions from Nature’s readers.Namrata Jain speaks about espousing the merits of a green lab during her PhD programme. Jain, who now works as a marketing consultant at My Green Lab, a non-profit organization in San Diego, California, also suggests training programmes for researchers in which they can learn more about lab emissions. “There is a vast potential to improve the way science is done today and to incorporate sustainability into our lab practice,” she says.Kathryn Ann-Ramirez Aguilar champions a more efficient use of space, reducing waste and saving costs as part of her role as a manager in the Green Labs programme at the University of Colorado Boulder. “The only item in the lab that was asking us to save resources was a sticker on the light switch,” she says of her inspiration to combat lab waste. “I thought to myself that we must be able to do more than just turn off the lights when we leave.”Cintia Milagre, an organic chemist at São Paulo State University in Brazil, who also runs a green-lab programme, describes her experiences managing labs with reduced costs and carbon footprints. She says working in lower-resource areas often requires researchers to think more about the environmental impact of their work.The session was held on 5 August 2021. The three participants also suggested more resources to support green-lab initiatives and took part in a live Q&A discussion about how researchers at all career stages can make efforts to reduce wastage — often saving money for their labs in the process.It forms part of Nature Careers’ ongoing 2021 webinar programme. For information about future topics, please visit https://www.nature.com/webcasts/.

    doi: https://doi.org/10.1038/d41586-021-02352-6

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    A staggering store of water is revealed in Earth’s crust

    People gather at a pump in India to collect groundwater. Accessible, fresh water makes up only a fraction of the water in Earth’s crust. Credit: Jack Laurenson/Lnp/Shutterstock

    Water resources
    17 August 2021
    A staggering store of water is revealed in Earth’s crust

    Modelling work shows that crustal groundwater accounts for more water than the world’s ice caps and glaciers.

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    The depths of Earth’s crust hold a huge volume of ancient, salty water that has been undetected until now.Grant Ferguson at the University of Saskatchewan in Saskatoon, Canada, and his colleagues calculated how much of this underground water should exist. They analysed a global database of the types of rock that make up the uppermost 10 kilometres of the planet’s continental crust. Nearly 88% is hard crystalline rock, and 12% is sedimentary rock, which has large spaces between its grains.The scientists calculated how much water could exist between the grains of both of these rock types, and estimated that the uppermost 10 kilometres of Earth’s crust holds nearly 44 million cubic kilometres of water. That’s more than the amount frozen in glaciers and the ice sheets of Greenland and Antarctica.Most of this vast reservoir lies at a depth of between 1 kilometre and 10 kilometres, beyond the reach of wells that could tap it. The groundwater used by many farmers for irrigation and by billions of people for drinking is at much shallower depths.

    Geophys. Res. Lett. (2021)

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