The objective of this study was to develop and test nanoparticle- and polymer-based bioactive amended sorbents to enhance stormwater runoff treatment in best management practices (BMPs). Red cedar wood and expanded shale were the sorbents tested. Red cedar wood chips (RC) were modified with 3-(trihydroxysilyl) propyldimethyloctadecyl ammonium chloride (TPA) and silver nanoparticles (AgNPs) at different mass loadings (0.36 mg/g, 0.67 mg/g, and 0.93 mg/g for TPA and 0.33 mg/g and 0.68 mg/g for AgNPs) to simultaneously improve the sorption of organic and inorganic contaminants and pathogenic deactivation in BMPs treating stormwater runoff. Unmodified expanded shale is often used as a filter material for stormwater treatment and was used as a base comparison. The results showed that TPA and AgNPs loading onto red cedar increased the Langmuir maximum sorption coefficient (Q) for polycyclic aromatic hydrocarbons, up to 35 fold and 29 fold, respectively, compared to unmodified red cedar. In the case of heavy metals, Q for lead increased with increased loading of TPA and AgNPs, whereas no significant change in the Q value for cadmium was observed, while zinc and nickel sorption slightly decreased. The Langmuir maximum sorption coefficient of copper was higher for modified red cedar; however, no correlation was observed with TPA or AgNP loadings. The log reduction value (LRV) for Escherichia coli using unmodified red cedar was <1 log, while modified red cedar exhibited LRV up to 2.90 ± 0.50 log for 0.67 mg/g TPA-RC and up to 2.10 ± 0.90 log for 0.68 mg/g AgNP-RC. Although AgNP-modified red cedar shows a comparable performance to TPA-RC, the high cost of production may limit the use of AgNP-amended materials. While TPA-modified red cedar has advantages of lower cost and lower toxicity, the fate, transport, and environmental implications of TPA in natural environments has not been fully evaluated. The findings from this study show that if BMPs were to incorporate the modified red cedar, stormwater treatment of PAH and E. coli could be enhanced, and the quality of the treated water will improve.
The rock cycle is a key component of geoscience education at all levels. In this paper, we report on a new guided inquiry curricular module, Sleuthing Through the Rock Cycle, which has a blended online/offline constructivist design with comprehensive teaching notes and has been successful in pilot use in Rhode Island middle and high school classrooms over the past 3 y. The module consists of two overarching activities: (1) SherRock Holmes and the Case of the Mystery Rock Samples, and (2) Cracking the Case of the Changing Rocks. The module encourages hands-on activities, peer collaboration, and real-time teacher review of embedded textual and reflection components. Overall, Rhode Island teachers report that the module is an outstanding teaching tool and that the associated professional development is empowering. 2013 National Association of Geoscience Teachers. [DOI: 10.5408/12-326.1]
Significance As societies move toward nature-based infrastructure to provide ecosystem services for sustainable urban environmental management, knowledge of urban soils remains a critical gap. An 11-city comparison of urban to reference preurban soil profiles revealed how urbanization modifies the presence and ordering of soil layers and its properties. Urban soils had fewer horizons than their preurban counterparts, with a predominant absence of intermediate B horizons. The loss of B horizons, which are not easily replaced, as they form over decades to millennia, can affect ecosystem functions, with potentially wide-ranging consequences for ecosystem services in cities.
Abstract The U.S. Environmental Protection Agency National Stormwater Calculator ( NSWC ) simplifies the task of estimating runoff through a straightforward simulation process based on the EPA Stormwater Management Model. The NSWC accesses localized climate and soil hydrology data, and options to experiment with low‐impact development ( LID ) features for parcels up to 5 ha in size. We discuss how the NSWC treats the urban hydrologic cycle and focus on the estimation uncertainty in soil hydrology and its impact on runoff simulation by comparing field‐measured soil hydrologic data from 12 cities to corresponding NSWC estimates in three case studies. The default NSWC hydraulic conductivity is 10.1 mm/h, which underestimates conductivity measurements for New Orleans, Louisiana (95 ± 27 mm/h) and overestimates that for Omaha, Nebraska (3.0 ± 1.0 mm/h). Across all cities, the NSWC prediction, on average, underestimated hydraulic conductivity by 10.5 mm/h compared to corresponding measured values. In evaluating how LID interact with soil hydrology and runoff response, we found direct hydrologic interaction with pre‐existing soil shows high sensitivity in runoff prediction, whereas LID isolated from soils show less impact. Simulations with LID on higher permeability soils indicate that nearly all of pre‐ LID runoff is treated; while features interacting with less‐permeable soils treat only 50%. We highlight the NSWC as a screening‐level tool for site runoff dynamics and its suitability in stormwater management.
