Biogenic volatile organic compounds as a potential stimulator for organic contaminant degradation by soil microorganisms

The effects of monoterpenes on the degradation of ¹⁴C-2,4-dichlorophenol (DCP) were investigated in soils collected from areas surrounding monoterpene and non-monoterpene-emitting vegetation. Indigenous microorganisms degraded ¹⁴C-2,4-DCP to ¹⁴CO₂, after 1 d contact time. Degradation was enhanced by prior exposure of the soils to 2,4-DCP for 32 d, increasing extents of mineralisation up to 60%. Monoterpene amendments further enhanced 2,4-DCP degradation, but only following pre-exposure to both 2,4-DCP and monoterpene, with total 2,4-DCP mineralisation extents of up to 71%. Degradation was greatest at the higher monoterpene concentrations (≥1 μg kg⁻¹). Total mineralisation extents were similar between concentrations, but higher than the control and the 0.1 μg kg⁻¹ amendment, indicating that increases in monoterpene concentration has a diminishing enhancing effect. We suggest that monoterpenes can stimulate the biodegradation of 2,4-DCP by indigenous soil microorganisms and that monoterpene amendment in soils is an effective strategy for removing organic contaminants.     

Short-Term Forecasting of Nitrogen Dioxide (NO<Subscript>2</Subscript>) Levels Using a Hybrid Statistical and Air Mass History Modelling Approach

A novel hybrid model has been developed to support the provision of real-time air quality forecasts. Statistical techniques have been applied in parallel with air mass history modelling to provide an efficient and accurate forecasting system with the ability to identify high NO₂ events, which tend to be the episodes of most significance in Ireland. Air mass history modelling and k-means clustering are used to identify air mass types that lead to high NO₂ levels in Ireland. Trajectory matching techniques allow data associated with these air masses to be partitioned during model development. Non-parametric regression (NPR) has been applied to describe nonlinear variations in concentration levels with wind speed, direction and season and produce a set of linearized factors which, together with other meteorological variables, are employed as inputs to a multiple linear regression. The model uses an innovative integrated approach to combine the NPR with the air mass history modelling results. On validation, a correlation coefficient of 0.75 was obtained, and 91 % of daily maximum (hourly averaged) NO₂ predictions were within a factor of two of the measured value. High pollution events were well captured, as indicated by strong agreement between measured and modelled high percentile values. The model requires only simple input data, does not require an emission inventory and utilises very low computational resources. It represents an accurate and efficient means of producing real-time air quality forecasts and, when used in combination with forecaster experience, is a useful tool for identifying periods of poor air quality 24 h in advance. The hybrid approach outlined in this paper can easily be applied to produce high-quality forecasts of both NO₂ and additional pollutants at new locations/countries where historical monitoring data are available.     

Population growth rate and carrying capacity for springtails Folsomia candida exposed to ivermectin.

Forecasting the effects of stressors on the dynamics of natural populations requires assessment of the joint effects of a stressor and population density on the population response. The effects can be depicted as a contour map in which the population response, here assessed by population growth rate, varies with stress and density in the same way that the height of land above sea level varies with latitude and longitude. We present the first complete map of this type using as our model Folsomia candida exposed to five different concentrations of the widespread anthelmintic veterinary medicine ivermectin in replicated microcosm experiments lasting 49 days. The concentrations of ivermectin in yeast were 0.0, 6.8, 28.8, 66.4, and 210.0 mg/L wet weight. Increasing density and chemical concentration both significantly reduced the population growth rate of Folsomia candida, in part through effects on food consumption and fecundity. The interaction between density and ivermectin concentration was "less-than-additive," implying that at high density populations were able to compensate for the effects of the chemical. This result demonstrates that regulatory protocols carried out at low density (as in most past experiments) may seriously overestimate effects in the field, where densities are locally high and populations are resource limited (e.g., in feces of livestock treated with ivermectin).     

Effects of Mowing and Prescribed Fire on Plant Community Structure and Function in Rare Coastal Sandplains,Nantucket Island,MA, USA

Coastal sandplains provide habitat for a suite of rare and endangered plant and wildlife species in the northeastern United States. These early successional plant communities were maintained by natural and anthropogenic disturbances including salt spray, fire, and livestock grazing, but over the last 150 years, a decrease in anthropogenic disturbance frequency and intensity has resulted in a shift towards woody shrub dominance at the expense of herbaceous taxa. This study quantified the effects of more than a decade of dormant season disturbance-based vegetation management (mowing and prescribed fire) on coastal sandplain plant community composition on Nantucket Island, Massachusetts, USA. We used time-series plant cover data from two similar sites to evaluate the effectiveness of disturbance management for restoring herbaceous species cover and reducing woody shrub dominance. Our results indicate that applying management outside of the peak of the growing season has not been effective in maintaining or increasing the cover of herbaceous species. While management activities resulted in significant (P < 0.01) increases in herbaceous species immediately after treatment, woody species recolonized and dominated treated sites within 3-years post treatment at the expense of graminoids and forbs. These results highlight the difficulties associated with directing ecological succession using disturbance-based management to maintain rare, herbaceous species in coastal sandplain systems that were once a prevalent landscape component under historically chronic anthropogenic disturbance. Further experimentation with growing season disturbance-based management and different combinations of management techniques could provide insights into management alternatives for maintaining herbaceous conservation targets in coastal sandplains.     

Carbonate mineralization of volcanic province basalts

Flood basalts are receiving increasing attention as possible host formations for geologic sequestration of anthropogenic CO₂, with studies underway in the United States, India, Iceland, and Canada. Basalts from the United States, India, and South Africa were reacted with aqueous dissolved CO₂ and aqueous dissolved CO₂–H₂S mixtures under supercritical CO₂ (scCO₂) conditions to study the geochemical reactions resulting from injection of CO₂ in such formations. Despite the basalt samples having similar bulk chemical composition, mineralogy and dissolution kinetics, long-term static experiments show significant differences in rates of mineralization as well as compositions and morphologies of precipitates that form when the basalts are reacted with CO₂ and CO₂–H₂S mixtures in water. For example, basalt from the Newark Basin in the United States was by far the most reactive of any basalt tested to date. Reacted grains from the Newark Basin basalt appeared severely weathered and contained extensive carbonate precipitates with significant Fe content. In comparison, the post-reacted samples associated with the Columbia River basalts from the United States contained calcite grains with classic “dogtooth spar” morphology and trace cation substitution (Mg and Mn). Carbonation of the other basalts produced precipitates with compositions that varied chemically throughout the entire testing period. The Karoo basalt from South Africa appeared the least reactive, with very limited mineralization occurring during the testing with CO₂-saturated water. Compositional differences in the precipitates suggest changes in fluid chemistry unique to the dissolution behavior of each basalt sample reacted with CO₂-saturated water. No convincing correlations were identified between basalt reactivity and differences in bulk composition, mineralogy, glassy mesostasis quantity or composition. Moreover, the relative reactivity of different basalt samples was unexpectedly different in the experiments conducted with aqueous dissolved CO₂–H₂S mixtures versus those with CO₂ only. For example, the Karoo basalt was highly reactive in the presence of aqueous dissolved CO₂–H₂S, as evident by nodules of carbonate coating the basalt grains after 181 days of testing. However, the most reactive basalt in CO₂–H₂O, Newark Basin, formed only iron sulfide coatings in tests with a CO₂–H₂S mixture, which inhibited carbonate mineralization.     

Community relations and mining: Core to business but not “core business”

Over the past two decades the global mining industry has witnessed the necessity and emergence of community relations and development (CRD) functions, essentially under the rubric of sustainable development and corporate social responsibility (CSR). These functions provide companies with mechanisms through which to engage and manage their relationships with key stakeholder groups, share development benefits and protect business interests. Despite widespread claims by the industry that companies have adopted CSR as a ‘core competence’, we argue that the industry has yet to incorporate the CRD function as part of ‘core business’ at the level of practice. This article characterises a CRD function and related processes within the context of a large-scale mining operation in West Africa. Findings reflect a more universal trend relating to the function and organisational positioning of CRD practice in the resources sector. The authors argue that functional equity needs to be established if the sustainable development agenda is to have a genuine future within the mining industry.     

Resistant weeds were controlled by the combined use of herbicides and bioherbicides

The intensive and abundant use of synthetic herbicides has been questioned in recent decades due to the strong dependence and also the resistance effects that are identified in weeds. Several grain crops suffer from the weed control system because many of the weeds are already resistant to the main herbicides that are used. In recent years, there has been a large gap in the market without the addition of new synthetic herbicides with mechanisms of action that differ from those already existing. The objective of this short piece is to address and overcome this challenge and bring an innovative and alternative solution that proposes a synergistic action system between bioherbicides produced by the fungus Trichoderma koningiopsis and synthetic herbicides (2,4‐dichlorophenoxyacetic acid, glyphosate, and ammonium glufosinate). The plants included in this study were Bidens pilosa (amor seco, or in the United States, beggar ticks or Spanish needle), Euphorbia heterophylla (adeus‐brasil), and Conyza bonariensis (margaridinha‐do‐campo, or, in the United States, hairy fleabane or asthmaweed). It was verified that, in the application of the biocomposites in the presence of chemical herbicides, potentiation of the phytotoxic action (100%) occurred under the target plants, emphasizing phytotoxicity to the weed, C. bonariensis, which is currently resistant to available herbicides. The bioherbicides studied have promising characteristics to be explored in the biocontrol of weeds.     

Critical Review on the Public Health Impact of Norovirus Contamination in Shellfish and the Environment: A UK Perspective

We review the risk of norovirus (NoV) infection to the human population from consumption of contaminated shellfish. From a UK perspective, risk is apportioned for different vectors of NoV infection within the population. NoV spreads mainly by person-to-person contact or via unsanitary food handling. NoV also enters the coastal zone via wastewater discharges resulting in contamination of shellfish waters. Typically, NoV persists in the marine environment for several days, with its presence strongly linked to human population density, wastewater discharge rate, and efficacy of wastewater treatment. Shellfish bioaccumulate NoV and current post-harvest depuration is inefficient in its removal. While NoV can be inactivated by cooking (e.g. mussels), consumption of contaminated raw shellfish (e.g. oysters) represents a risk to human health. Consumption of contaminated food accounts for 3–11% of NoV cases in the UK (~74,000 cases/year), of which 16% are attributable to oyster consumption (11,800 cases/year). However, environmental and human factors influencing NoV infectivity remain poorly understood. Lack of standard methods for accurate quantification of infective and non-infective (damaged) NoV particles represent a major barrier, hampering identification of an appropriate lower NoV contamination limit for shellfish. Future management strategies may include shellfish quality assessment (at point of harvest or at point of supply) or harvesting controls. However, poor understanding of NoV inactivation in shellfish and the environment currently limits accurate apportionment and risk assessment for NoV and hence the identification of appropriate shellfish or environmental quality standards.