Contributions toward sustainable development: a bibliometric analysis of sustainability reporting research

Environmental Science and Pollution Research - The study determines the development of the sustainability reporting domain using a dataset of publications extracted from the Web of Science (WoS)...     

PFAS Experts Symposium: Statements on regulatory policy,chemistry and analytics,toxicology, transport/fate,and remediation for per‐ and polyfluoroalkyl substances (PFAS) contamination issues

Sixty leading members of the scientific, engineering, regulatory, and legal communities assembled for the PFAS Experts Symposium in Arlington, Virginia on May 20 and 21, 2019 to discuss issues related to per‐ and polyfluoroalkyl substances (PFAS) based on the quickly evolving developments of PFAS regulations, chemistry and analytics, transport and fate concepts, toxicology, and remediation technologies.  The Symposium created a venue for experts with various specialized skills to provide opinions and trade perspectives on existing and new approaches to PFAS assessment and remediation in light of lessons learned managing other contaminants encountered over the past four decades. The following summarizes several consensus points developed as an outcome of the Symposium:

• Regulatory and policy issues: The response by many states and the US Environmental Protection Agency (USEPA) to media exposure and public pressure related to PFAS contamination is to relatively quickly initiate programs to regulate PFAS sites. This includes the USEPA establishing relatively low lifetime health advisory levels for PFAS in drinking water and even more stringent guidance and standards in several states. In addition, if PFAS are designated as hazardous substances at the federal level, as proposed by several Congressional bills, there could be wide‐reaching effects including listing of new Superfund sites solely for PFAS, application of stringent state standards, additional characterization and remediation at existing sites, reopening of closed sites, and cost renegotiation among PRPs.
• Chemistry and analytics: PFAS analysis is confounded by the lack of regulatory‐approved methods for most PFAS in water and all PFAS in solid media and air, interference with current water‐based analytical methods if samples contain high levels of suspended solids, and sample collection and analytical interference due to the presence of PFAS in common consumer products, sampling equipment, and laboratory materials.
• Toxicology and risk: Uncertainties remain related to human health and ecological effects for most PFAS; however, regulatory standards and guidance are being established incorporating safety factors that result in part per trillion (ppt) cleanup objectives. Given the thousands of PFAS that may be present in the environment, a more appropriate paradigm may be to develop toxicity criteria for groups of PFAS rather than individual PFAS.
• Transport and fate: The recalcitrance of many perfluoroalkyl compounds and the capability of some fluorotelomers to transform into perfluoroalkyl compounds complicate conceptual site models at many PFAS sites, particularly those involving complex mixtures, such as firefighting foams. Research is warranted to better understand the physicochemical properties and corresponding transport and fate of most PFAS, of branched and linear isomers of the same compounds, and of the interactions of PFAS with other co‐contaminants such as nonaqueous phase liquids. Many PFAS exhibit complex transport mechanisms, particularly at the air/water interface, and it is uncertain whether traditional transport principles apply to the ppt levels important to PFAS projects. Existing analytical methods are sufficient when combined with the many advances in site characterization techniques to move rapidly forward at selected sites to develop and test process‐based conceptual site models.
• Existing remediation technologies and research: Current technologies largely focus on separation (sorption, ion exchange, or sequestration). Due to diversity in PFAS properties, effective treatment will likely require treatment trains. Monitored natural attenuation will not likely involve destructive reactions, but be driven by processes such as matrix diffusion, sorption, dispersion, and dilution.

The consensus message from the Symposium participants is that PFAS present far more complex challenges to the environmental community than prior contaminants. This is because, in contrast to chlorinated solvents, PFAS are severely complicated by their mobility, persistence, toxicological uncertainties, and technical obstacles to remediation—all under the backdrop of stringent regulatory and policy developments that vary by state and will be further driven by USEPA. Concern was expressed about the time, expense, and complexity required to remediate PFAS sites and whether the challenges of PFAS warrant alternative approaches to site cleanups, including the notion that adaptive management and technical impracticability waivers may be warranted at sites with expansive PFAS plumes. A paradigm shift towards receptor protection rather than broad scale groundwater/aquifer remediation may be appropriate.     

Assessment of the Conservation Measures Partnership's effort to improve conservation outcomes through adaptive management

Conservation practice has demonstrated an increasing desire for accountability of actions, particularly with respect to effectiveness, efficiency, and impact to clearly identified objectives. This has been accompanied by increased attention to achieving adaptive management. In 2002, practitioners representing several prominent conservation nongovernmental organizations (NGOs) launched a community of practice called the Conservation Measures Partnership (CMP). The partnership CMP has worked to establish standards of conservation practice to improve accountability of conservation actions through adaptive management. The focal organizing framework for CMP has been the Open Standards for the Practice of Conservation (OS). We evaluated, through an online survey and personal interviews, the first decade of CMP and the OS. The CMP has garnered a positive reputation among agencies, NGOs, and funders and has succeeded in developing a large user base of the OS. However, CMP has not fully achieved its goal of making the OS standard operating procedure for the largest NGOs (e.g., The Nature Conservancy, World Wildlife Fund), despite it being widely used within these organizations. This lack of institutionalization is attributable to multiple causes, including an increase in the number of partially overlapping decision‐support frameworks and challenges achieving full‐cycle adaptive management. Users strongly believed the OS fosters better conservation practice and highly valued the OS for improving their practice. A primary objective of the OS is to assist practitioners to achieve full‐cycle adaptive management to better integrate learning into improving the effectiveness and efficiency of actions. However, most practitioners had not yet achieved cycle completion for their projects. To improve the effectiveness of CMP, OS, and conservation practice in general, we recommend collaborative efforts among the proponents of multiple decision‐support frameworks to foster strong institutional adoption of a common set of adaptive‐management standards for conservation accountability.     

Hydrogen Sulfide Generation in Simulated Construction and Demolition Debris Landfills: Impact of Waste Composition

Abstract

Hydrogen sulfide (H₂S) generation in construction and demolition (C&D) debris landfills has been associated with the biodegradation of gypsum drywall. Laboratory research was conducted to observe H₂S generation when drywall was codisposed with different C&D debris constituents. Two experiments were conducted using simulated landfill columns. Experiment 1 consisted of various combinations of drywall, wood, and concrete to determine the impact of different waste constituents and combinations on H₂S generation. Experiment 2 was designed to examine the effect of concrete on H₂S generation and migration. The results indicate that decaying drywall, even alone, leached enough sulfate ions and organic matter for sulfate-reducing bacteria (SRB) to generate large H₂S concentrations as high as 63,000 ppmv. The codis-posed wastes show some effect on H₂S generation. At the end of experiment 1, the wood/drywall and drywall alone columns possessed H₂S concentrations >40,000 ppmv. Conversely, H₂S concentrations were <1 ppmv in those columns containing concrete. Concrete plays a role in decreasing H₂S by increasing pH out of the range for SRB growth and by reacting with H₂S. This study also showed that wood lowered H₂S concentrations initially by decreasing leachate pH values. Based on the results, two possible control mechanisms to mitigate H₂S generation in C&D debris landfills are suggested.     

Satellite telemetry reveals behavioural plasticity in a green turtle population nesting in Sri Lanka

Satellite transmitters were deployed on ten green turtles (Chelonia mydas) nesting in Rekawa Sanctuary (RS-80.851°E 6.045°N), Sri Lanka, during 2006 and 2007 to determine inter-nesting and migratory behaviours and foraging habitats. Nine turtles subsequently nested at RS and demonstrated two inter-nesting strategies linked to the location of their residence sites. Three turtles used local shallow coastal sites within 60 km of RS during some or all of their inter-nesting periods and then returned to and settled at these sites on completion of their breeding seasons. In contrast, five individuals spent inter-nesting periods proximate to RS and then migrated to and settled at distant (>350 km) shallow coastal residence sites. Another turtle also spent inter-nesting periods proximate to RS and then migrated to a distant oceanic atoll and made forays into oceanic waters for 42 days before transmissions ceased. This behavioural plasticity informs conservation management beyond protection at the nesting beach.     

Geographic variation in allele frequency of the gamete recognition protein M7 lysin throughout a mosaic blue mussel hybrid zone

Divergence at gamete recognition loci is hypothesized to result in speciation in broadcast spawning invertebrates. Many gamete recognition loci evolve quickly and show patterns of positive selection, yet the advantage of divergence is rarely known. M7 lysin is a sperm protein in the Mytilus edulis species complex that shows evidence of adaptive evolution. This locus is polymorphic with two distinct clades within Mytilus galloprovincialis, one of which, the D clade, shows the strongest signal of positive selection. We tested whether the geographic patterns in allele frequency were consistent with the hypothesis that positive selection on D clade alleles (G _D ) was due to reinforcement. Populations of M. edulis showed little evidence of introgression of G _D alleles, but there was no consistent evidence of reproductive character displacement. The lack of consistent patterns expected of reinforcement suggests that another mechanism is likely responsible for the adaptive divergence of M7 lysin.