Understanding plant biology and related microbial ecology as a means to phytoremediate soil and groundwater contamination has broadened and advanced the field of environmental engineering and science over the past 30 years. Using plants to transform and degrade xenobiotic organic pollutants delivers new methods for environmental restoration. Manipulations of the plant microbiome through bioaugmentation, endophytes, adding various growth factors, genetic modification, and/or selecting the microbial community via insertion of probiotics or phages for gene transfer are future areas of research to further expand this green, cost-effective, aesthetically pleasing technology�phytoremediation.

Bioremediation is a promising treatment technology for 1,4-dioxane-contaminated groundwater. However, metabolic dioxane-degrading bacteria identified to date are limited by their slow kinetics and inability to sustain growth at low dioxane concentrations (<100 μg/L). Furthermore, strains may underperform because of missing growth factors, such as amino acids or vitamins. In this work, we reevaluate Rhodococcus ruber strain 219 as a dioxane-degrading strain with bioaugmentation potential. We report rapid growth and metabolic dioxane degradation by R. ruber 219 when supplemented with thiamine (vitamin B1). We also discern that the strain lacks a complete de novo thiamine synthesis pathway, indicating that R. ruber 219 is a probable thiamine auxotroph. However, when supplemented with thiamine, the strain’s Monod kinetics (K s = 0.015 ± 0.03 μg/L) and exceedingly low S min (0.49 ± 1.16 μg/L) suggest this strain can maintain growth at very low dioxane concentrations (<100 μg/L). Accordingly, we demonstrate that thiamine-grown R. ruber 219 sustains degradation of dilute dioxane (<100 μg/L) to below health advisory levels. This is the first study to report sustained metabolic dioxane biodegradation to below health advisory levels of 0.35 μg/L. Overall, our findings solidify R. ruber 219 as a promising candidate for bioremediation of dioxane-contaminated groundwater.

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Since the beginning of the industrial revolution, humans have burned enormous quantities of coal, oil, and natural gas, rivaling nature’s elemental cycles of C, N, and S. The result has been a disruption in a steady state of CO2 and other greenhouse gases in the atmosphere, a warming of the planet, and changes in master variables (temperature, pH, and pε) of the sea affecting critical physical, chemical, and biological reactions. Humans have also produced copious quantities of N and P fertilizers producing widespread coastal hypoxia and low dissolved oxygen conditions, which now threaten even the open ocean. Consequently, our massive alteration of state variables diminishes coral reefs, fisheries, and marine ecosystems, which are the foundation of life on Earth. We point to a myriad of actions and alternatives which will help to stem the tide of climate change and its effects on the sea while, at the same time, creating a more sustainable future for humans and ecosystems alike.

Fecal contamination of Iowa recreational water bodies poses a threat to water quality as well as human health. Concern regarding the health effects of waterborne pathogens resulted in 149 beach advisories across 39 state-owned beaches during the 2015 beach season alone. While the presence of pollution is often clear, its cause and source may be difficult to identify. Furthermore, the current practice in Iowa of sampling once per week leads to high uncertainty and inadequately protects swimmers from exposure. The objective of this study was to determine the influential environmental factors and sources causing spikes in fecal contamination at F.W. Kent Park Lake in Oxford, IA, and to develop a predictive model of beach E. coli concentrations. Water samples were collected at the swimming beach as well as throughout the watershed from May to October, 2015. All samples were analyzed for Escherichia Coli using the IDEXX Colilert enumeration method. Together with weekly data from 2012 through 2014, two predictive models of E. coli based upon influential environmental and water quality variables were developed using EPA Virtual Beach software. These models proved to be more accurate than the current method used to assess risks to swimmers that assumes bacterial concentrations remain constant between samples. In addition, through statistical analysis and modeling, this study found evidence that the main source of fecal contamination were wild geese that frequent the beach. v