Highway runoff quality in Ireland

Highway runoff has been identified as a significant source of contaminants that impact on the receiving aquatic environment. Several studies have been completed documenting the characteristics of highway runoff and its implication to the receiving water in the UK and elsewhere. However, very little information is available for Ireland. The objective of this study was to determine the quality of highway runoff from major Irish roads under the current road drainage design and maintenance practice. Four sites were selected from the M4 and the M7 motorways outside Dublin. Automatic samplers and continuous monitoring devices were deployed to sample and monitor the runoff quality and quantity. More than 42 storm events were sampled and analysed for the heavy metals Cd, Cu, Pb, and Zn, 16 US EPA specified PAHs, volatile organic compounds including MTBE, and a number of conventional pollutants. All samples were analysed based on the Standard Methods. Significant quantities of solids and heavy metals were detected at all sites. PAHs were not detected very often, but when detected the values were different from quantities observed in UK highways. The heavy metal concentrations were strongly related to the total suspended solids concentrations, which has a useful implication for runoff management strategies. No strong relationship was discovered between pollutant concentrations and event characteristics such as rainfall intensity, antecedent dry days (ADD), or rainfall depth (volume). This study has demonstrated that runoff from Irish motorways was not any cleaner than in the UK although the traffic volume at the monitored sites was relatively smaller. This calls for a site specific investigation of highway runoff quality before adopting a given management strategy.     

Natural attenuation of coal combustion waste in river sediments

The weathering of coal combustion products (CCPs) in a lotic environment was assessed following the Tennessee Valley Authority (Kingston, TN) fly ash release of 2008 into surrounding rivers. Sampled materials included stockpiled ash and sediment collected from 180 to 880 days following the release. Total recoverable concentrations of heavy metals and metalloids in sediment were measured, and percent ash was estimated visually or quantified by particle counts. Arsenic and selenium in sediment were positively correlated with percent ash. For samples collected 180 days after the release, total concentrations of trace elements downstream of the release were greater than reference levels but less than concentrations measured in stockpiled ash. Total concentrations of trace elements remained elevated in ash-laden sediment after almost 2.5 years. A sequential extraction procedure (SEP) was used to speciate selected fractions of arsenic, copper, lead, nickel, and selenium in decreasing order of bioavailability. Concentrations of trace elements in sequentially extracted fractions were one to two orders of magnitude lower than total recoverable trace elements. The bulk of sequentially extractable trace elements was associated with iron-manganese oxides, the least bioavailable fraction of those measured. By 780 days, trace element concentrations in the SEP fractions approached reference concentrations in the more bioavailable water soluble, ion exchangeable, and carbonate-bound fractions. For each trace element, the percentage composition of the bioavailable fractions relative to the total concentration was calculated. These SEP indices were summed and shown to significantly decrease over time. These results document the natural attenuation of leachable trace elements in CCPs in river sediment as a result of the loss of bioavailable trace elements over time.     

Arsenic mobilization and attenuation by mineral-water interactions: implications for managed aquifer recharge

Managed aquifer recharge (MAR) has potential for addressing deficits in water supplies worldwide. It is also widely used for preventing saltwater intrusion, maintaining the groundwater table, and augmenting ecological stream flows, among many other beneficial environmental applications. However, field MAR sites have experienced arsenic mobilization from aquifer formation minerals due to induced changes in groundwater chemistry. To address this environmental concern, it is crucial to understand the potential sources and sinks impacting arsenic mobilization. This paper outlines important mineral-water interactions that can occur at MAR sites. Detailed information on minerals of concern, physiochemical processes for arsenic mobilization or attenuation, and the potential impact of microbial activity and hydrology on these processes is provided. Based on these mineral-water interactions, guidelines for predicting arsenic mobility are presented, and recommendations are made concerning MAR site monitoring. The review emphasizes important aspects in correlating interfacial reactions to reactive transport modeling and elucidating future challenges, a first step toward developing safer and more sustainable MAR operations.     

Does Engagement in Advocacy Hurt the Credibility of Scientists? Results from a Randomized National Survey Experiment

It is often assumed that issue advocacy will compromise the credibility of scientists. We conducted a randomized controlled experiment to test public reactions to six different advocacy statements made by a scientist—ranging from a purely informational statement to an endorsement of specific policies. We found that perceived credibility of the communicating scientist was uniformly high in five of the six message conditions, suffering only when he advocated for a specific policy—building more nuclear power plants (although credibility did not suffer when advocating for a different specific policy—carbon dioxide limits at power plants). We also found no significant differences in trust in the broader climate science community between the six message conditions. Our results suggest that climate scientists who wish to engage in certain forms of advocacy have considerable latitude to do so without risking harm to their credibility, or the credibility of the scientific community.     

Shark recreational fisheries: Status,challenges, and research needs

For centuries, the primary manner in which humans have interacted with sharks has been fishing. A combination of their slow-growing nature and high use-values have resulted in population declines for many species around the world, and to date the vast majority of fisheries-related work on sharks has focused on the commercial sector. Shark recreational fishing remains an overlooked area of research despite the fact that these practices are popular globally and could present challenges to their populations. Here we provide a topical overview of shark recreational fisheries, highlighting their history and current status. While recreational fishing can provide conservation benefits under certain circumstances, we focus our discourse on the relatively understudied, potentially detrimental impacts these activities may have on shark physiology, behavior, and fitness. We took this angle given the realized but potentially underestimated significance of recreational fishing for shark conservation management plans and stock assessments, in hopes of creating a dialogue around sustainability. We also present a series of broad and focused research questions and underpin areas of future research need to assist with the development of this emergent area of research.     

Performance evaluation of an in situ source area combined remedy for the remediation of commingled chlorinated ethanes and ethenes

The chlorinated volatile organic compounds (CVOCs), tetrachloroethene (PCE), trichloroethene (TCE), and 1,1,1‐trichloroethane (1,1,1‐TCA), often found as commingled contaminants of concern (COCs) in groundwater, can degrade via a variety of biotic and abiotic reductive pathways. In situ remediation of a groundwater contaminant source area containing commingled 1,1,1‐TCA, PCE, and TCE was conducted using a combined remedy/treatment train approach. The first step was to create geochemically reducing conditions in the source area to degrade the CVOCs to lesser chlorinated CVOCs (i.e., 1,1‐dichloroethane [1,1‐DCA], 1,1‐dichlorethene [1,1‐DCE], cis‐1,2‐dichoroethene [cis‐1,2‐DCE], and vinyl chloride [VC]) via enhanced reductive dechlorination (ERD). Carbon substrates were injected to create microbial‐induced geochemically reducing conditions. An abiotic reductant (zero‐valent iron [ZVI]) was also used to further degrade the CVOCs, minimizing the generation of 1,1‐DCE and VC, and co‐precipitate temporarily mobilized metals. An in situ aerobic zone was created downgradient of the treatment zone through the injection of oxygen. Remaining CVOC degradation products and temporarily mobilized metals (e.g., iron and manganese) resulting from the geochemically reducing conditions were then allowed to migrate through the aerobic zone. Within the aerobic zone, the lesser chlorinated CVOCs were oxidized and the solubilized metals were precipitated out of solution. The injection of a combination of carbon substrates and ZVI into the groundwater system at the site studied herein resulted in the generation of a geochemically reducing subsurface treatment zone that has lasted for more than 4.5 years. Mass concentrations of total CVOCs were degraded within the treatment zone, with near complete transformation of chlorinated ethenes and a more than 90 percent reduction of CVOC mass concentrations. Production of VC and 1,1‐DCE has been minimized through the combined effects of abiotic and biological processes. CVOC concentrations have declined over time and temporarily mobilized metals are precipitating out of the dissolved phase. Precipitation of the dissolved metals was mitigated using the in situ oxygenation system, also resulting in a return to aerobic conditions in downgradient groundwater. Chloroethane (CA) is the dominant CVOC degradation product within the treatment zone and downgradient of the treatment zone, and it is expected to continue to aerobically degrade over time. CA did not accumulate within and near the aerobic oxygenation zone. The expectations for the remediation system are: (1) the concentrations of CVOCs (primarily in the form of CA) will continue to degrade; (2) total organic carbon concentrations will continue to decline to pre‐remediation levels; and, (3) the groundwater geochemistry will experience an overall trend of transitioning from reducing back to pre‐remediation mildly oxidizing conditions within and downgradient of the treatment zone.     

Climate Skepticism in British Newspapers, 2007–2011

Climate skepticism in the UK media has not been a major focus of recent research. This paper aims to help fill the gap by looking at the incidence of skeptical voices in UK newspapers across three periods: 2007, 2009/2010, and 2010/2011. After analyzing more than 3200 articles, it finds that skeptical voices increased their presence markedly across all newspapers and all types of articles in the second period, and maintained a significant presence in many in the third. Uncontested skeptical voices were particularly prevalent in opinion pieces and editorials in right-leaning newspapers in the second. It also finds that skeptical voices or opinions were more likely to be included in pieces written by in-house non-specialist columnists than by environment editors or correspondents. The negative implications of the results for public understanding and the quality of public debate are then explored.     

Extricating Membership as a PRP at Hazardous Waste Disposal Sites

Corporations often become potentially responsible parties (PRPs) at hazardous waste sites because of their past transportation or disposal of hazardous substances at such sites. Determining a PRP's potential liability for the assessment and cleanup of hazardous waste sites is a challenging effort and often results in disputes among other PRPs regarding appropriate allocation of response action costs to each party. Further, public companies have an obligation to report probable and reasonably estimable costs under Generally Accepted Accounting Principles (GAAP) for environmental liabilities at their current or prior hazardous waste sites. The first step in such an evaluation is to determine whether or not a PRP can extricate themselves from any association with the subject site or, alternatively, demonstrate de minimis status. This article describes the methods by which PRPs can extricate themselves from liability associated with response action costs at contaminated sites, including: evaluating a PRP's prior settlements or indemnifications with other PRPs; identifying insurance coverage or other financial assurance instruments for the disposal facility; and examining applicable statutes of limitations against when a PRP received notification from the regulatory agency. The article also presents a case study discussing how a PRP with a portfolio of 72 hazardous waste disposal sites was able to extricate itself from the majority of these sites, resulting in only four sites where the PRP was determined to be a PRP and where an associated allocable share was assigned. © 2014 Wiley Periodicals, Inc.     

In Situ Measurement of Hydrochloric Acid in Rocket Exhaust Clouds Using a Remotely Piloted Aircraft

Abstract

An instrumentation system employing an RPV (remotely piloted vehicle) platform was developed for temporally and spatially resolved air pollution measurements, and was used to measure the evolution of gas-phase HC1 in exhaust clouds from a solid rocket motor firing and fuel pit burns. A thermistor and a sensitive (ppmv-level), rapid-response (<0.1 sec) infrared absorption sensor for HC1 were mounted in a flow channel in the RPV, permitting concentration and temperature measurements to be made in the cloud on a several-meter scale. The RPV system was flown in a series of field tests at Thiokol Corporation’s Elkton, MD division to evaluate the HC1 content of the exhaust products of a new Mg-based fuel formulation. Measurements were made in the clouds from Al-based and Mg-based solid fuel pit burns and a Mg-fueled motor firing over periods of several minutes. Elevated temperatures and HC1 concentrations were found to be temporally correlated with video images of the particulate cloud. Cl originating from the ammonium perchlorate oxidizer appeared in the exhaust as HC1 in each of the tests. Both the macroscopic and local cloud parameters indicate that the Mg-based fuel may provide some reduction in HC1 concentration compared to the standard Al-based fuel.     

The Relationship between Historic Industrial Site Use and Environmental Contamination

ABSTRACT

A methodology is presented for estimating the probability that particular classes of environmental contaminants will be of concern at brownfield redevelopment sites. These probabilities are predicted by a logistics model that is based on qualitative information about site history and status. This qualitative information comprises data that would be collected through a Phase I Environmental Site Assessment (ESA), including historic site use, current use and ownership status, and the nature of adjacent properties. The model is fit and demonstrated using a set of 59 former industrial sites in southwestern Pennsylvania that were collected from the files of the Pennsylvania Department of Environmental Protection (PADEP). Predictive models are developed for exceedances of contaminants as grouped into the following classes: metals, chlorinated hydrocarbons, fuel hydrocarbons, and PCBs. A procedure for estimating the parametric uncertainty of the model predictions is also illustrated. This method can serve as a starting point for more effective usage of existing Phase I ESA information and for evaluation of the benefit of obtaining additional site information. By increasing the decision-making value of existing (or inexpensive) data, this method can help to reduce the information asymmetry that may be an obstacle to redevelopment.