Capacity for Watershed Cumulative Effects Assessment and Management: Lessons from the Lower Fraser River Basin, Canada

This study examines the capacity to support the cumulative effects assessment and management for watersheds. The research is set in the Lower Fraser River Basin, a densely populated sub-watershed in British Columbia’s lower mainland. Eight requirements or requisites for the watershed cumulative effects assessment and management are applied to evaluate current capacity for implementation in the Lower Fraser, and to identify the areas in need of capacity development. Results show that advancing watershed cumulative effects assessment and management requires not only good science but also leadership in the coordination of monitoring programs, and in ensuring the appropriate incentives and penalties for engagement and nonengagement. The lack of leadership in this regard is the result of existing governance structures arranged around the political boundaries, which have produced over time multiple agencies and jurisdictional fragmentation. Notwithstanding this, we argue that the watershed is the most appropriate scale for assessing and managing the cumulative effects to complex ecosystems.     

Response of sugar maple to calcium addition to northern hardwood forest

Watershed budget studies at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA, have demonstrated high calcium depletion of soil during the 20th century due, in part, to acid deposition. Over the past 25 years, tree growth (especially for sugar maple) has declined on the experimental watersheds at the HBEF. In October 1999, 0.85 Mg Ca/ha was added to Watershed 1 (W1) at the HBEF in the form of wollastonite (CaSiO3), a treatment that, by summer 2002, had raised the pH in the Oie horizon from 3.8 to 5.0 and, in the Oa horizon, from 3.9 to 4.2. We measured the response of sugar maple to the calcium fertilization treatment on W1. Foliar calcium concentration of canopy sugar maples in W1 increased markedly beginning the second year after treatment, and foliar manganese declined in years four and five. By 2005, the crown condition of sugar maple was much healthier in the treated watershed as compared with the untreated reference watershed (W6). Following high seed production in 2000 and 2002, the density of sugar maple seedlings increased significantly on W1 in comparison with W6 in 2001 and 2003. Survivorship of the 2003 cohort through July 2005 was much higher on W1 (36.6%) than W6 (10.2%). In 2003, sugar maple germinants on W1 were approximately 50% larger than those in reference plots, and foliar chlorophyll concentrations were significantly greater (0.27 g/m2 vs. 0.23 g/m2 leaf area). Foliage and fine-root calcium concentrations were roughly twice as high, and manganese concentrations twice as low in the treated than the reference seedlings in 2003 and 2004. Mycorrhizal colonization of seedlings was also much greater in the treated (22.4% of root length) than the reference sites (4.4%). A similar, though less dramatic, difference was observed for mycorrhizal colonization of mature sugar maples (56% vs. 35%). These results reinforce and extend other regional observations that sugar maple decline in the northeastern United States and southern Canada is caused in part by anthropogenic effects on soil calcium status, but the causal interactions among inorganic nutrition, physiological stress, mycorrhizal colonization, and seedling growth and health remain to be established.     

Predictive abilities of numerical sediment quality guidelines in Sydney Harbour, Australia, and vicinity

Matching chemical and toxicological data of surficial sediments from Sydney Harbour, Australia, and vicinity, were collected to evaluate predictive abilities of Effects Range-Low (ERL), Effects Range-Median (ERM) and other sediment quality guidelines (SQGs). Samples (n=103) containing a wide range of chemicals and concentrations were subjected to a battery of 4-6 toxicity tests. ERLs and functionally equivalent low-range SQGs were highly predictive of non-toxicity when not exceeded, as incidences of toxicity were 0-8%. ERMs and other mid-range SQGs were predictive of toxicity in combined test data with > or = 80% of toxic samples with one or more SQG exceeded. Predictive abilities of mid-range SQGs were low for amphipod survival tests (generally < 20% toxic samples), but the incidence of toxicity increased with increasing numbers of SQGs exceeded and increasing mean SQG quotients. Predictive abilities of SQGs generally matched their narrative intent when outcomes of multiple toxicity tests were considered, and were consistent with North American data. Functionally equivalent SQGs gave comparable results (except where developed for single chemical classes), indicating that predictive abilities were primarily influenced by sensitivities of test species and/or the bioavailability of contaminants.     

Degradation of aqueous piperazine in carbon dioxide capture

Concentrated, aqueous piperazine (PZ) is a novel solvent for carbon dioxide (CO₂) capture by absorption/stripping. One of the major advantages of PZ is its resistance to thermal degradation and oxidation.At 135 and 150 °C, 8 m PZ is up to two orders of magnitude more resistant to thermal degradation than 7 m monoethanolamine (MEA). After 18 weeks at 150 °C, only 6.3% of the initial PZ was degraded, yielding an apparent first order rate constant for amine loss of 6.1 × 10^?9 s^?1. PZ was the most resistant amine tested, with the other screened amines shown in order of decreasing resistance: 7 m 2-amino-2-methyl-1-propanol, 7 m Diglycolamine^®, 7 m N-(2-hydroxyethyl)piperazine, 7 m MEA, 8 m ethylenediamine, and 7 m diethylenetriamine. Thermal resistance allows the use of higher temperatures and pressures in the stripper, potentially leading to overall energy savings.Concentrated PZ solutions demonstrate resistance to oxidation compared to 7 m MEA solutions. Experiments investigating metal-catalyzed oxidation found that PZ solutions were 3–5 times more resistant to oxidation than MEA. Catalysts tested were 1.0 mM iron (II), 4.0–5.0 mM copper (II), and a combination of stainless steel metals (iron (II), nickel (II), and chromium (III)). Inhibitor A reduced PZ degradation catalyzed by iron (II) and copper (II).     

Experimental assessment and validation of quantification methods for cellulose content in municipal wastewater and sludge

Environmental Science and Pollution Research - Cellulose, mostly in the form of toilet paper, forms a major component of the particulates in raw municipal wastewater, which could lead to...     

Sodium bisulfate and a sodium bisulfate/tannin mixture decreases pH when added to an in vitro incubated poultry cecal or fecal contents while reducing Salmonella Typhimurium marker strain survival and altering the microbiome

The objective of the present study was to investigate the ability of animal feed-grade sodium bisulfate (SBS) and a mixture of sodium bisulfate/tannin to inhibit the growth of Salmonella using an anerobic in vitro mixed cecal culture to mimic the conditions within the chicken cecum. An initial inoculum of Salmonella Typhimurium was introduced to an anerobic dilution solution containing 1/3000 diluted cecal bacteria and solids consisting of ground chicken feed and different percentages of solid SBS or SBS/tannin, and surviving organisms were enumerated. Two different experimental designs were employed. In the “unadapted” treatment, the S. Typhimurium was added at the beginning of the culture incubation along with cecal bacteria and chicken feed/SBS or chicken feed/SBS/tannin. In the “adapted” treatment, S. Typhimurium was added after a 24 hour pre-incubation of the cecal bacteria with the chicken feed/SBS or chicken feed/SBS/tannin. Adding SBS resulted in reduction of pH in the cultures which paralleled with the reduction of S. Typhimurium. The SBS alone was found to be inhibitory to S. Typhimurium in the adapted treatment at all concentrations tested (0.25, 0.5, and 0.75%), and the degree of inhibition was concentration-dependent. Salmonella Typhimurium was completely killed in the adapted culture with 0.5% SBS after 24 and 48 h. The SBS/tannin mixture was less inhibitory than SBS alone at the same concentrations in side-by-side comparisons. Testing at a 0.5% SBS concentration, chicken age had little or no effect on log reduction of S. Typhimurium relative to age-matched control cultures without SBS, but age did affect the absolute number of S. Typhimurium surviving, with the greatest decreases occurring at 2 and 4 weeks of age (approx. 10³ S. Typhimurium surviving) compared to 6 weeks of age (approx. 10⁵ Salmonella surviving). Microbiome analysis with an Illumina MiSeq platform was conducted to investigate bacterial compositional changes related to the addition of SBS. The relative abundance of Firmicutes (at the phylum level) was decreased, and genera Lactobacillus and Faecalibacterium were increased when SBS was added to the anaerobic mixed culture containing either fecal or cecal material. The antimicrobial action of feed-grade SBS may represent a potential pre-harvest control measure for Salmonella in poultry production.     

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.     

Recruitment to food by the German yellowjacket, Vespula germanica

The hypothesis that Vespula germanica foragers can recruit nestmates to food resources was tested using a protocol that controlled for the biasing effects of social factors at the resource, including local enhancement and food-site marking substances. Foragers from an observation colony in the field were trained to visit a dish of scented corn syrup solution 15?m east of the nest. A second feeding station, 22?m northeast of the nest, offered incoming foragers a choice between food with the training scent and food with a control scent. Significantly more naive foragers arriving at that station chose the food with the training scent. We conclude that the German yellowjacket is able to recruit nestmates to carbohydrate food sources, and that recruits use food odor to locate the source of food being brought into the nest.