Twenty-year inter-annual trends and seasonal variations in precipitation and stream water chemistry at the Bear Brook Watershed in Maine, USA

Mean annual concentration of ${\textrm{SO}}_{4}^{2-}$ in wet-only deposition has decreased between 1988 and 2006 at the paired watershed study at Bear Brook Watershed in Maine, USA (BBWM) due to substantially decreased emissions of SO₂. Emissions of NO_x have not changed substantially, but deposition has declined slightly at BBWM. Base cations, ${\textrm{NH}}_{4}^{+}$ , and Cl^??? concentrations were largely unchanged, with small irregular changes of <1 μeq L^???1 per year from 1988 to 2006. Precipitation chemistry, hydrology, vegetation, and temperature drive seasonal stream chemistry. Low flow periods were typical in June–October, with relatively greater contributions of deeper flow solutions with higher pH; higher concentrations of acid-neutralizing capacity, Si, and non-marine Na; and low concentrations of inorganic Al. High flow periods during November–May were typically dominated by solutions following shallow flow paths, which were characterized by lower pH and higher Al and DOC concentrations. Biological activity strongly controlled ${\textrm{NO}}_{3}^{-}$ and K^?+?. They were depressed during the growing season and elevated in the fall. Since 1987, East Bear Brook (EB), the reference stream, has been slowly responding to reduced but still elevated acid deposition. Calcium and Mg have declined fairly steadily and faster than ${\textrm{SO}}_{4}^{2-}$ , with consequent acidification (lower pH and higher inorganic Al). Eighteen years of experimental treatment with (NH₄)₂SO₄ enhanced acidification of West Bear Brook’s (WB) watershed. Despite the manipulation, ${\textrm{NH}}_{4}^{+}$ concentration remained below detection limits at WB, while leaching of ${\textrm{NO}}_{3}^{-}$ increased. The seasonal pattern for ${\textrm{NO}}_{3}^{-}$ concentrations in WB, however, remained similar to EB. Mean monthly concentrations of ${\textrm{SO}}_{4}^{2-}$ have increased in WB since 1989, initially only during periods of high flow, but gradually also during base flow. Increases in mean monthly concentrations of Ca^2?+?, Mg^2?+?, and K^?+? due to the manipulation occurred from 1989 until about 1995, during the depletion of base cations in shallow flow paths in WB. Progressive depletion of Ca and Mg at greater soil depth occurred, causing stream concentrations to decline to pre-manipulation values. Mean monthly Si concentrations did not change in EB or WB, suggesting that the manipulation had no effect on mineral weathering rates. DOC concentrations in both streams did not exhibit inter- or intra-annual trends.     

The relationship between country and individual household wealth and climate change concern: the mediating role of control

The relationship between wealth and climate change concern has been a focus of several studies. In this article, we hypothesize that richer households (and countries) are less concerned about climate change because wealth provides a buffer against some of the related risks. This leads people in wealthier countries and households to perceive a greater sense of control over climate change impacts, which in turn results in lower levels of concern. We tested this hypothesis using a unique household survey encompassing 11 OECD countries and over 10,000 households and applying mixed multi-level regression models. Our results confirmed a statistically significant negative relationship between country and household wealth and individuals’ perceptions of the seriousness of climate change. This study contributes to current literature by showing that this relationship is mediated through sense of control, measured at the country level by the country’s readiness index and at the individual household level by the extent of adoption of energy efficiency improvements. These findings raise the question of how best to incentivize action on climate change amongst those with the ability—but not necessarily the motivation—to respond.

     

Innovation in the Knowledge Age: implications for collaborative science

Current trends validate the notion that multifaceted, multimodal interdisciplinary collaborations lead to increased research productivity in publications and citations, compared to those achieved by individual researchers. Moreover, it may be that scientific breakthroughs are increasingly achieved by interdisciplinary research teams. Nonetheless, despite the perceived importance of collaboration and its bibliometric benefits, today’s scientists are still trained to be autonomous, work individually, and encourage their graduate students to do the same—perpetuating values which impede the creation of collaborative space between disciplines. As a consequence, scientists working in teams typically report serious obstacles to collaboration. This paper builds off of recent recommendations from a 2015 National Academies report on the state of team science which emphasizes greater definition of roles, responsibility, accountability, goals, and milestones. However, these recommendations do not address the subjective, relational components of collaboration which can drive innovation and creativity. The relational side of collaboration is key to understanding the capacity and capabilities of the knowledge workers, such as scientists and engineers, who comprise interdisciplinary research teams. The authors’ recommendations, grounded in organizational communication and knowledge worker literature, include a renewed focus on the process of organizing through communication rather than focusing on organization as an outcome or consequence of teamwork, leading and cultivating team members rather than managing them, and the need to address self-driven, rather than external, motivations to engage in knowledge work.     

Fecal coliforms, caffeine and carbamazepine in stormwater collection systems in a large urban area

Water samples from streams, brooks and storm sewer outfall pipes that collect storm waters across the Island of Montréal were analyzed for caffeine, carbamazepine and fecal coliforms. All samples contained various concentrations of these tracers, indicating a widespread sanitary contamination in urban environments. Fecal coliforms and caffeine levels ranged over several orders of magnitude with a modest correlation between caffeine and fecal coliforms (R² value of 0.558). An arbitrary threshold of 400 ng caffeine L⁻¹ allows us to identify samples with an elevated fecal contamination, as defined by more than 200 colony-forming units per 100 mL (cfu 100 mL⁻¹) of fecal coliforms. Low caffeine levels were sporadically related to high fecal coliform counts. Lower levels of caffeine and fecal coliforms were observed in the brooks while the larger streams and storm water discharge points contained over ten times more. The carbamazepine data showed little or no apparent correlation to caffeine. These data suggest that this storm water collection system, located in a highly urbanized urban environment, is widely contaminated by domestic sewers as indicated by the ubiquitous presence of fecal contaminants as well as caffeine and carbamazepine. Caffeine concentrations were relatively well correlated to fecal coliforms, and could potentially be used as a chemical indicator of the level of contamination by sanitary sources. The carbamazepine data was not significantly correlated to fecal coliforms and of little use in this dataset.     

Determination of organochlorine pesticide residue in sediment and water from the Densu river basin, Ghana

The distribution of organochlorine pesticides in the aquatic ecosystem from the Densu river revealed varying levels of concentration in water and the sediment samples. Three locations were sampled along the river to evaluate the levels of organochlorine pesticide residue in the river. Sediment and surface water samples were extracted by soxhlet and liquid-liquid extraction respectively and analyzed using Gas Chromatograph coupled with electron capture detector. The detectable organochlorine pesticides were gamma-hexachlorocyclohexane (HCH), delta-hexachlorocyclohexane, heptachlor, aldrin and dieldrin. The other pesticides that were investigated are gamma-chlordane, alpha endosulfan, endosulfan sulfate, p,p′-DDT and its metabolite p,p′-DDE, methoxychlor, endrin and its metabolite endrin aldehyde and endrin ketone. The order of increasing frequency of detection of samples was higher in sediment than water. In sediment, the mean concentration ranged from 0.030 μg kg⁻¹ dry weight (endrin) to 10.98 μg kg⁻¹ dry weight (aldrin). The highest detected concentration of organochlorine in water was endosulfan sulfate with mean concentration of 0.185 μg L⁻¹. Analysis of variance indicated significant differences for most organochlorine pesticide residue in the sediment sampled from the various locations. Some of the levels of organochlorine pesticides detected in water were relatively high compared to guideline values set by World Health Organization and Australia and thus could be harmful if the trend is not checked.     

Dietary exposure to technical hexabromocyclododecane (HBCD) alters courtship, incubation and parental behaviors in American kestrels (Falco sparverius)

Hexabromocyclododecane (HBCD) is a high production volume brominated flame retardant that has been detected in the environment and wildlife at increasing concentrations. This study was designed to determine potential effects of dietary exposure to environmentally relevant levels of HBCD on behavior during reproduction in captive American kestrels. Twenty kestrel pairs were exposed to 0.51 μg technical HBCD g⁻¹ kestrel d⁻¹ from 4 weeks prior to pairing until chicks hatched (∼75 d). Ten pairs of controls received the safflower oil vehicle only and were used for comparison. During the courtship period the chitter-calls were reduced in both sexes (p = 0.038) and females performed fewer bonding displays (p = 0.053). Both sexes showed a propensity to be less active than controls during courtship. The reduction in male courtship behavior was correlated with reduced courtship behaviors of females (p ? 0.008) as well as reduced egg mass (p = 0.019). During incubation, nest temperatures of treatment pairs were lower at mid-incubation (p = 0.038). HBCD-exposed males performed fewer key parental behaviors when rearing nestlings, including entering the nest-box, pair-bonding displays and food-retrievals. HBCD-exposed females appeared to compensate for the reduced parental behavior of their mates by performing these same behaviors more frequently than controls (p = 0.004, p = 0.027, p = 0.025, respectively). This study demonstrates that HBCD affects breeding behavior in American kestrels throughout the reproductive season and behavioral alterations were linked to reproductive changes (egg size). This is the first study to report HBCD effects on reproductive behavior in any animal model.     

Water Supply Reliability Tradeoffs between Removing Reservoir Storage and Improving Water Conveyance in California

Population growth, climate change, aging infrastructure, and changing societal values alter how water must be managed in the 21st Century. O'Shaughnessy Dam, located in Yosemite National Park, has been identified as a possible candidate for dam removal. It is a component of San Francisco's Hetch Hetchy System and is operated for water supply and hydropower. This article describes a spatially scaled approach to analyze water reliability without O'Shaughnessy Dam, but with improved water conveyance between the Hetch Hetchy System and existing reservoirs and aqueducts at the watershed, regional Bay Area, and statewide scales. It broadens previous research to highlight larger scale implications of removing O'Shaughnessy Dam and evaluates the role of improved water conveyance for water management. CALifornia Value Integrated Network, a large‐scale hydro‐economic model evaluates intertied water management using estimated urban and agricultural water demands for year 2050 with 72‐year historical and warm, dry hydrologic conditions. Results suggest that O'Shaughnessy Dam can be removed with additional conveyance at any spatial scale while maintaining water reliability. With a warm, dry climate, water reliability, and storage decline, indicating removing O'Shaughnessy Dam may have less effect on water management than climate change when conveyance is improved between the Hetch Hetchy System and nearby systems. Improving water conveyance can sometimes substitute for water storage in storage‐rich watersheds.     

Management of the Spring Snowmelt Recession in Regulated Systems

In an effort to restore predictable ecologically relevant spring snowmelt recession flow patterns in rivers regulated by dams, this study defined a methodology by which spring flow regimes can be modeled in regulated systems from the quantifiable characteristics of spring snowmelt recessions in unregulated rivers. An analysis of eight unregulated rivers across the Sierra Nevada mountain range in California found that unregulated systems behaved similarly with respect to seasonal spring patterns and recession limb curvature, and thus prescribed flows could be designed in a manner that mimics those predictable characteristics. Using the methodology to quantify spring recession flows in terms of a daily percent decrease in flow, a series of flow recession scenarios were created for application in an existing hydrodynamic model for the regulated Rubicon River. The modeling results showed that flow recessions with slow ramping rates similar to those observed in unregulated rivers (less than 10% per day) were likely to be protective of native aquatic species, such as the Foothill yellow‐legged frog, while flows that receded at greater rates would likely result in desiccation of egg masses and potential stranding of tadpoles and fry. Furthermore, recession rates of less than 10% per day provided the most spatially diverse hydraulic habitat in the modeled domain for an appropriate duration in spring to support all native species guilds and maximize aquatic biodiversity.     

Determination of Heavy Metals in Indoor Dust From Primary School (Sri Serdang,Malaysia): Estimation of the Health Risks

Heavy metal concentrations (Pb, Cd, and Cu) in classroom indoor dust were measured. The health risk (non-carcinogenic) of these heavy metals in classroom indoor dust to children was assessed based on United States Environmental Protection Agency health risk model. Indoor classroom dust samples were collected from 21 locations including windows, fans, and floors at a primary school in Sri Serdang, Malaysia. Classroom dust samples were processed using aqua regia method and analyzed for Pb, Cd, and Cu concentrations. The highest average heavy metal concentrations were found in windows, followed by floor and fan. Pb concentrations ranged from 34.17 μg/g to 101.87 μg/g, Cd concentrations ranged from 1.73 μg/g to 7.5 μg/g, and Cu concentrations ranged from 20.27 μg/g to 82.13 μg/g. Ventilation and cleaning process were found as the possible factors that contributed to heavy metal concentration in window, floor, and fan. Moreover, the hazard index (HI) and hazard quotient (HQ) values for heavy metals Cd and Cu were less than one. By contrast, the HI and HQ values for Pb (maximum values) were more than one, indicating potential non-carcinogenic risk to children. Long-term persistence of leaded petrol, building materials, interior paint, school located near industrial areas and major roads, as well as vehicle emission are the factors attributed to the presence of heavy metals in classroom dust. Further research under a long-term monitoring plan and actual values in a health risk model is crucial before a final decision on heavy metal exposure and its relationship to young children health risks can be made. Nevertheless, the findings of this study provide crucial evidence to include indoor dust quality in school assessment because the environmental processes and impacts of surrounding school area have health risk implications on young children.