The EPA Ecosystem Services Tool Selection Portal.

The dynamics of an environmental decision-making context can be complicated. The use of decision support tools can help better facilitate restoring and maintaining ecosystems that provide environmental benefits (ecosystem services) to people. Although an ecosystem services assessment tool is designed for specific purposes, having access to a comprehensive suite of tools offers the user additional insight and resources to help in decision making. A range of approaches exist to connect ecosystem services to a given decision context ranging from less to more complex: using the best professional judgment; applying examples from other efforts; testing individual tool applications; and using a systematic, decision-tree approach to navigate among relevant tools and frameworks. The U.S. Environmental Protection Agency developed a decision-tree approach for a user to navigate the question of how to choose among a suite of ecosystem services assessment tools for three decision contexts: (1) ecological risk assessments; (2) cleanup of contaminated sites; (3) and generic structured decision-making processes. This tool selection navigator was developed with/for the intended user, including developing crosswalks between tool functionality and the user's language for what they require in a tool. To navigate the tool, the user first chooses one of three decision contexts. Second, the user selects among the different phases of the decision process. Third, the user selects among a few ecosystem-services related tasks relevant to the decision context chosen to identify potential tools. The tool uses simple language to navigate the decision pathways and provides the user with a suite of potential ES resources and tools for their given decision context.

Increasing in situ bioremediation effectiveness through field-scale application of molecular biological tools.

Leveraging the capabilities of microorganisms to reduce (degrade or transform) concentrations of pollutants in soil and groundwater can be a cost-effective, natural remedial approach to manage contaminated sites. Traditional design and implementation of bioremediation strategies consist of lab-scale biodegradation studies or collection of field-scale geochemical data to infer associated biological processes. While both lab-scale biodegradation studies and field-scale geochemical data are useful for remedial decision-making, additional insights can be gained through the application of Molecular Biological Tools (MBTs) to directly measure contaminant-degrading microorganisms and associated bioremediation processes. Field-scale application of a standardized framework pairing MBTs with traditional contaminant and geochemical analyses was successfully performed at two contaminated sites. At a site with trichloroethene (TCE) impacted groundwater, framework application informed design of an enhanced bioremediation approach. Baseline abundances of 16S rRNA genes for a genus of obligate organohalide-respiring bacteria (i.e., Dehalococcoides) were measured at low abundances (101-102 cells/mL) within the TCE source and plume areas. In combination with geochemical analyses, these data suggested that intrinsic biodegradation (i.e., reductive dechlorination) may be occurring, but activities were limited by electron donor availability. The framework was utilized to support development of a full-scale enhanced bioremediation design (i.e., electron donor addition) and to monitor remedial performance. Additionally, the framework was applied at a second site with residual petroleum hydrocarbon (PHC) impacted soils and groundwater. MBTs, specifically qPCR and 16S gene amplicon rRNA sequencing, were used to characterize intrinsic bioremediation mechanisms. Functional genes associated with anaerobic biodegradation of diesel components (e.g., naphthyl-2-methyl-succinate synthase, naphthalene carboxylase, alkylsuccinate synthase, and benzoyl coenzyme A reductase) were measured to be 2-3 orders of magnitude greater than unimpacted, background samples. Intrinsic bioremediation mechanisms were determined to be sufficient to achieve groundwater remediation objectives. Nonetheless, the framework was further utilized to assess that an enhanced bioremediation could be a successful remedial alternative or complement to source area treatment. While bioremediation of chlorinated solvents, PHCs, and other contaminants has been demonstrated to successfully reduce environmental risk and reach site goals, the application of field-scale MBT data in combination with contaminant and geochemical data analyses to design, implement, and monitor a site-specific bioremediation approach can result in more consistent remedy effectiveness.

Communicating about Contaminated Site Cleanup using Coordinated and Consistent Metrics: Opportunity and Challenge for the U.S. Department of Energy.

Over $500 billion has gone toward cleanup of large contaminated sites owned and/or operated by the U.S. Federal Government over the past 30 years. Nevertheless, some stakeholders worry about the risks associated with what they perceive as a slow process of cleanup, as well as the positive and negative impacts of the cleanup activities themselves. Therefore, it is important for both the U.S. taxpayer and workers and residents living near the sites that are impacted by site conditions and activities, to clearly understand the progress that is being made toward achieving published cleanup goals, and a timeline for completion. This manuscript asks how lessons drawn from risk communication literature can inform practices for communicating metrics related to cleanup progress at U.S Department of Energy former nuclear weapon sites to different audiences. Following the review of literature, we present a case study that explores metrics being used and communicated on the websites of DOE and its largest sites, and discuss the consistency of these metrics and implications for public understanding and trust of progress being made. We finish the manuscript by applying the principles from the literature to the findings from the case study to suggest how the DOE could consider improvements in the format, content or delivery of cleanup progress metrics to its various audiences.

Phytoremediation removal rates of benzene, toluene, and chlorobenzene.

Phytoremediation is a sustainable remedial approach, although performance efficacy is rarely reported. In this study, we assessed a phytoremediation plot treating benzene, toluene, and chlorobenzene. A comparison of the calculated phytoremediation removal rate with estimates of onsite contaminant mass was used to forecast cleanup periods. The investigation demonstrated that substantial microbial degradation was occurring in the subsurface. Estimates of transpiration indicated that the trees planted were removing approximately 240,000 L of water per year. This large quantity of water removal implies substantial removal of contaminant due to large amounts of contaminants in the groundwater; however, these contaminants extensively sorb to the soil, resulting in large quantities of contaminant mass in the subsurface. The total estimate of subsurface contaminant mass was also complicated by the presence of non-aqueous phase liquids (NAPL), additional contaminant masses that were difficult to quantify. These uncertainties of initial contaminant mass at the site result in large uncertainty in the cleanup period, although mean estimates are on the order of decades. Collectively, the model indicates contaminant removal rates on the order of 10-2-100 kg/tree/year. The benefit of the phytoremediation system is relatively sustainable cleanup over the long periods necessary due to the presence of NAPL.

[Brief Introduction of Pollution Sites Remediation and Risk Assessment and Its Policy Making in United States].

Site remediation has become an imperative part of environmental protection in China due to recent economic development, urban spreading, new industries replacing old ones, relocation of old industrial sites, and increased environmental conscience. This paper mainly introduced the concept, method, calculation, risk assessment and management for polluted sites remediation based on experience from California, USA. Further, the paper presented the concept of vapor intrusion and how to use vapor intrusion methodology to determine site remediation standard. Mathematical modeling approaches were also discussed in terms of how to determine the residual pollutant concentrations in soil and how to calculate indoor vapor concentrations. Based on risk assessment, California Environmental Protection Agency, Water Resources Control Board issued a 'Low Threat Underground Storage Tank Case Closure Policy' for impacted underground storage tank sites. The numerical criteria in the Policy were based on calculations of human health risk assessment. Finally, a real case study in California, USA, was presented to demonstrate how the risk assessment calculations were applied in polluted site remediation, which helps to answer the question of 'how clean is clean'.