Environmental Engineering for the 21st Century: Increasing Diversity and Community Participation to Achieve Environmental and Social Justice.

Communities of color are disproportionately burdened by environmental pollution and by obstacles to influence policies that impact environmental health. Black, Hispanic, and Native American students and faculty are also largely underrepresented in environmental engineering programs in the United States. Nearly 80 participants of a workshop at the 2019 Association of Environmental Engineering and Science Professors (AEESP) Research and Education Conference developed recommendations for reversing these trends. Workshop participants identified factors for success in academia, which included adopting a broader definition for the impact of research and teaching. Participants also supported the use of community-based participatory research and classroom action research methods in engineering programs for recruiting, retaining, and supporting the transition of underrepresented students into professional and academic careers. However, institutions must also evolve to recognize the academic value of community-based work to enable faculty, especially underrepresented minority faculty, who use it effectively, to succeed in tenure promotions. Workshop discussions elucidated potential causal relationships between factors that influence the co-creation of research related to academic skills, community skills, mutual trust, and shared knowledge. Based on the discussions from this workshop, we propose a pathway for increasing diversity and community participation in the environmental engineering discipline by exposing students to community-based participatory methods, establishing action research groups for faculty, broadening the definition of research impact to improve tenure promotion experiences for minority faculty, and using a mixed methods approach to evaluate its impact.

Total mercury loadings in sediment from gold mining and conservation areas in Guyana.

The Low Carbon Development Strategy proposed in June 2009 by the government of Guyana in response to the Reducing Emissions from Deforestation and Forest Degradation in Developing Countries program has triggered evaluation of forest-related activities, thereby acting as a catalyst for improvements in Guyana's small- to medium-scale gold mining industry. This has also shed light on areas committed to conservation, something that has also been handled by Non Governmental Organizations. This paper compares water quality and mercury concentrations in sediment from four main areas in Guyana, two that are heavily mined for gold using mercury amalgamation methods (Arakaka and Mahdia) and two that are considered conservation areas (Iwokrama and Konashen). Fifty-three sediment and soil mercury loadings ranged from 29 to 1,200 ng/g and averaged 215 ± 187 ng/g for all sites with similar averages in conservation and mining areas. Sediment loadings are within the range seen in French Guiana and Suriname, but conservation area samples had higher loadings than the corresponding uncontaminated baselines. Type of ore and location in the mining process seemed to influence mercury loadings. Mercury sediment loadings were slightly positively correlated with pH (correlation coefficient = 0.2; p value < 0.001) whereas no significant correlations were found with dissolved oxygen or turbidity.

Delivering sustainable infrastructure that supports the urban built environment.

Sustainable living will require megacity-level infrastructural support designs and paradigms.

Characterization and adsorption of arsenate and selenite onto Kemiron.

Kemiron, a commercially available, porous iron oxide sorbent was evaluated in batch systems for arsenate (As(V)) and selenite (Se(IV)) removal from aqueous solutions as a function of pH, ionic strength, and particle size (< 38 micro m and between 250 and 425 micro m). BET surface area of Kemiron is 39.8 m(2)/g and Electron dispersive spectroscopy (EDS) studies found Kemiron to be 40.37% iron and 42.25% oxygen by mass. Langmuir isotherms best described the As(V) and Se(IV) removal at pH 7 with maximum adsorption capacity of 82 mg/g and 52 mg/g respectively. As(V) and Se(IV) sorption decreased as pH increased and both anions were unaffected by sodium nitrate (NaNO(3)) background electrolyte. As(V) sorption was not affected in surface water samples from the Hillsborough River. Batch kinetic models of the experimental data on the 250 to 425 micro m particle size yielded mass transfer coefficients of 0.0008 min(-1) and 0.009 min(-1) for As(V) and Se(IV) respectively.

Variability in goethite surface site density: evidence from proton and carbonate sorption.

Goethite is a representative iron oxide in natural environments due to its abundance and thermodynamic stability and may be responsible for many surface-mediated processes, including ion retention and mobility in aqueous settings. A large variability in morphologies and specific surface areas of goethite crystals exists but little work has been done to compare surface reactivity between them. The present work offers experimental evidence for the existence of an inverse relationship between sorption capacity for protons and carbonate ions and specific surface area of goethite for three synthetic goethite preparations spanning surface area differences by a factor of 2. An explanation for this was found by assuming a variable reactive site density between preparations in direct relationship to their sorption capacity based on congruency of carbonate sorption computed on a per-site basis. Previous evidence of maximum sorption capacities supports this explanation, and site density ratios between the goethites studied here were obtained. Triple layer surface complexation modeling was successful in describing adsorption data for all goethite preparations using equal stoichiometries. A new formulation of standard state for activities of surface species based on a 1.0 mole fraction of sites on the solid allowed transformation of the conventional molar concentration-based affinity constants to values based on site occupancy. In this fashion, by applying the appropriate site density ratios, a single set of affinity constant values was found that described accurately the adsorption data for all preparations.