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Agrivoltaics shows promise as a practice that can reduce agricultural water use and plant water stress, while also increasing photovoltaic (PV) efficiency due to cooler temperatures of the panels from evapotranspiration below, but little work has investigated this practice at the residential scale. The objectives of this study were to evaluate the potential impact on water use and garden plants that would be found on a typical residential property, and evaluate the impact on solar PV energy production using residential agrivoltaics vs. typical roof-mount residential solar panels. Experimental plots were established to compare lettuce growth and water use between full-sun and a shaded agrivoltaics setup, and to compare temperatures and power production of the PV panels in the agrivoltaics plot vs. a typical roof-mount installation. Results showed significantly less irrigation requirements in the agrivolatic plot vs. the full-sun plot. Weights and leaf counts were significantly lower in the agrivolatic plot, though average leaf lengths were greater than in the full-sun plot. Roof-mount PV panel temperature was significantly higher than the agrivoltaics panel, depending on cloud cover and irradiance, which corresponded to up to a 3.6% decrease in power loss. Results show promise for both water conservation and energy production benefits, but further work is needed to determine optimal conditions that would not affect plant yield, and to verify effects on PV panel production under full load conditions.

This study investigated the effectiveness of metal and nutrient removal from stormwater in bioretention systems amended with agricultural byproducts. Both batch and column studies were cond...

This paper presents the preliminary stages of a research program centered on the development of a systems approach to water and sanitation service management and operation. Given high failure rates of rural water and sanitation infrastructure in developing countries, the sector now points to “systems approaches” as ways for practitioners and service stakeholders to understand the economic, institutional, political, environmental, and technical externalities that drive sustained service provision. Unfortunately, systems approaches and techniques often rely on expensive or inaccessible forms of quantitative data and are inaccessible to local stakeholders. Moreover, limited evidence exists for the true benefits of a systems approach in supporting sustained service provision. This research aims to fill these gaps by developing and refining an accessible participatory systems mapping approach to modeling factor interaction as a means to improve identification and characterization of leverage points for improved policy and practice for water and sanitation services. Coupled with this, application of computer models of the water and sanitation systems will help to identify areas of technical vulnerability that, alongside stakeholder interviews, will help prioritize which technical interventions, if any, would be most effective.

International experiential learning programs are becoming increasingly common and can be complex in both format and content. Due to the complexity of these programs, highlighting lessons learned is a critical activity for future program growth and improvement. In this vein, our paper highlights and learns from two international experiential learning activities in engineering, both at the undergraduate level, that focused on water supply infrastructure: one, a project-based experience in an urban setting in Amazonia Peru; the other, a mixed project and course-based experience in rural Chile. Overarching lessons learned from both programs relate to in-country partners, trip preparation, and interaction with local people. Site and partner selection that builds upon relationships and the clear articulation of expectations from both sides is critical for success. Both programs also highlighted the value of intensive trip preparation, including course organization, pre-trip team meetings, book studies, learning the local language, and meetings with local partners. Both programs suffered in their own way due to lack of meaningful interaction with one local people group or another. Throughout the paper, we highlight further insights and implications, whether unique or crosscutting, and link these to recommendations for future international experiential learning program development.

Municipal biosolids are commonly applied to agricultural lands as fertilizer, but this also poses potential risks to groundwater and surface water quality from constituents that may be mobilized during storm events. In the present study, an existing model, Groundwater Loading Effects of Agricultural Management Systems (GLEAMS), is modified to predict the fate and transport of organic contaminants from land-applied biosolids, primarily via addition of a labile biosolids organic carbon phase distinct from soil organic carbon. While capable of simulating contaminant transport in runoff and via percolation, only the runoff portion of the model was able to be calibrated using existing experimental data, and showed good agreement with field runoff data for acetaminophen, ibuprofen, triclosan, triclocarban, and estrone, but substantially under-predicted concentrations for carbamazepine, androstenedione, and progesterone. The model is applied to various scenarios using varied chemical properties, application date in the arid west, and application method (i.e., surface spreading vs. incorporation). Chemicals with longer half-lives and lower KOCs exhibited higher losses in runoff than chemicals with shorter half-lives and higher KOCs. For short half-life chemicals (i.e., ≤100 days), application at the beginning of the dry season resulted in the lowest losses. However, for long half-life chemicals (∼1000 days) with high KOC (10,000-100,000), application during the rainy season resulted in the lowest losses, because this caused organic carbon to be high during the period of highest runoff. While further work is necessary to calibrate the percolation and subsurface transport portion, the model can help predict environmental risk from land-application of biosolids, highlight gaps in our knowledge about how chemicals are mobilized and transported from biosolids, and help identify management practices that result in minimal impacts to water quality.

This paper describes the humanitarian effort to help bring clean water and solar power to people in need along the Amazon River in Nauta, Peru. George Fox University partnered with JungleMaster Ministries to create a long-term development plan, beginning with a full prototype of the system at the NGO's house in Nauta. The engineering design, installation, and test of the system are discussed in detail, along with a unique data acquisition system that was successfully employed and is currently recording data and sending it back to the USA for daily monitoring.

Municipal biosolids are commonly applied to land as soil amendment or fertilizer as a form of beneficial reuse of what could otherwise be viewed as waste. Balanced against this benefit are potential risks to groundwater and surface water quality from constituents that may be mobilized during storm events. The objective of the present study was to characterize the mobilization of selected endocrine-disrupting compounds, heavy metals, and total estrogenic activity in rainfall runoff from land-applied biosolids. Rainfall simulations were conducted on soil plots amended with biosolids. Surface runoff and leachate was collected and analyzed for the endocrine-disrupting compounds bisphenol A, 17α-ethynylestradiol, triclocarban, triclosan, octylphenol, and nonylphenol; a suite of 16 metals; and estrogenic activity via the estrogen receptor-mediated chemical activated luciferase gene expression (ER-CALUX) bioassay. Triclocarban (2.3-17.3 ng/L), triclosan (

Recent research has indicated that the antimicrobial chemical triclocarban (TCC) represents a new type of endocrine disruptor, amplifying the transcriptional activity of steroid hormones and their receptors while itself exhibiting little affinity for these receptors. The effects of TCC were studied in the freshwater mudsnail Potamopyrgus antipodarum. Specimens were exposed to concentrations ranging from 0.05 to 10.5 microg/L dissolved TCC and were removed and dissected, and embryos contained within the brood pouch were counted and classified as shelled or unshelled after two and four weeks of exposure. After four weeks, environmentally relevant TCC concentrations of 1.6 to 10.5 microg/L resulted in statistically significant increases in the number of unshelled embryos, whereas 0.2, 1.6, and 10.5 microg/L exposures significantly increased numbers of shelled embryos. The lowest observed effect concentration (LOEC) was 0.2 microg/L, the no observed effect concentration (NOEC) was 0.05 microg/L; the 10% effective concentration (EC10) and the median effective concentration (EC50) for unshelled effects were 0.5 microg/L and 2.5 microg/L, respectively. Given the widespread occurrence of TCC in the environment and the effects shown at environmentally relevant concentrations, these results indicate that TCC may be causing reproductive effects in the environment. Furthermore, the present study indicates that environmental risk from a new class of endocrine-disrupting chemicals (EDCs) is both qualitatively and quantitatively similar to risk from existing classes of EDCs.

A mathematical environmental transport model of roadside applied herbicides at the site scale (approximately 100 m) was stochastically applied using a Monte-Carlo technique to simulate the concentrations of 33 herbicides in stormwater runoff. Field surveys, laboratory sorption data, and literature data were used to generate probability distribution functions for model input parameters to allow extrapolation of the model to the regional scale. Predicted concentrations were compared to EPA acute toxicity end points for aquatic organisms to determine the frequency of potentiallytoxic outcomes. Results are presented for three geographical regions in California and two highway geometries. For a given herbicide, frequencies of potential toxicity (FPTs) varied by as much as 36% between region and highway type. Of 33 herbicides modeled, 16 exhibit average FPTs greater than 50% at the maximum herbicide application rate, while 20 exhibit average FPTs less than 50% at the minimum herbicide application rate. Based on these FPTs and current usage statistics, selected herbicides were determined to be more environmentally acceptable than others in terms of acute toxicity and other documented environmental effects. This analysis creates a decision support system that can be used to evaluate the relative water quality impacts of varied herbicide application practices.

Management decisions concerning the spraying of herbicides on highway roadsides are evaluated on the basis of their impact on resulting environmental risk. A mathematical transport model was previously applied to the State of California with a Monte Carlo technique, and in this study the results are manipulated to evaluate the risk reduction that results from restricting herbicide application on the basis of site characteristics or changing other application practices. Results show that eliminating herbicide applications where the slope of the grass adjacent to the highway is greater than 30° has little or no effect on risk. Eliminating application where the width of the grass adjacent to the highway is less than 2 m or where soil organic carbon content is less than 0.5% can lead to significant reductions in environmental risk for certain herbicides. Additionally, limiting the width of the spray zone and applying the minimum manufacturer-suggested application rate reduce the risk to aquatic ecosystems. Applying at the minimum rate has the greatest potential to decrease risk. Results of this study show that management decisions can have a significant effect on limiting herbicide runoff risks to aquatic ecosystems. Decision makers would have to weigh costs of alternatives to herbicide spraying for controlling roadside vegetation against the environmental risk reductions.