Bioconcentration of triclosan, methyl-triclosan, and triclocarban in the plants and sediments of a constructed wetland

Constructed wetlands are a potential method for the removal of two pharmaceutical and personal care products from wastewater effluent. Triclosan (TCS; 5-chloro-2-[2,4-dichlorophenoxy]phenol) and triclocarban (TCC; 3,4,4′-trichlorocarbanillide) are antimicrobial agents added to a variety of consumer products whose accumulation patterns in constructed wetlands are poorly understood. Here, we report the accumulation of TCS, its metabolite methyl-triclosan (MTCS; 5-chloro-2-[2,4-dichlorophenoxy]), and TCC in wetland plant tissues and sediments. Three wetland macrophytes: Typha latifolia, Pontederia cordata, and Sagittaria graminea were sampled from a constructed wetland in Denton, Texas, USA. MTCS concentrations were below the method detection limit (MDL) for all species. TCS root tissue concentrations in T. latifolia were significantly greater than root concentrations in P. cordata (mean ± SE in ng g⁻¹: 40.3 ± 11.3 vs. 15.0 ± 1.9, respectively), while for TCC, shoot tissue concentrations in S. graminea were significantly greater than in T. latifolia (22.8 ± 9.3 vs. 9.0 (MDL), respectively). For both TCS and TCC, T. latifolia root tissue concentrations were significantly greater than shoot concentrations (TCS: 40.3 ± 11.3 vs. 17.2 ± 0.2, TCC: 26.0 ± 3.6 vs. 9.0, (MDL)). TCC concentrations in P. cordata roots were significantly greater than in shoots (34.4 ± 5.3 vs. 15.4 ± 2.8, respectively). TCS concentrations in T. latifolia roots and sediments and TCC concentrations in sediments generally decreased from wetland inflow to outflow. To our knowledge, this is the first study documenting species and tissue specific differences in the accumulation of TCS and TCC in plants from an operational constructed wetland. The species specific differences in bioaccumulation suggest TCS and TCC removal from constructed wetlands could be enhanced through targeted plantings.     

PAH-sequestration capacity of granular and powder activated carbon amendments in soil, and their effects on earthworms and plants

A field lysimeter study was carried out to investigate whether the amendment of 2% powder and granular activated carbon (PAC and GAC) to a soil with moderate PAH contamination had an impact on the PAH bioaccumulation of earthworms and plants, since AC is known to be a strong sorbent for organic pollutants. Furthermore, secondary effects of AC on plants and earthworms were studied through growth and nutrient uptake, and survival and weight gain. Additionally, the effect of AC amendments on soil characteristics like pH, water holding capacity, and the water retention curve of the soil were investigated. Results show that the amendment of 2% PAC had a negative effect on plant growth while the GAC increased the growth rate of plants. PAC was toxic to earthworms, demonstrated by a significant weight loss, while the results for GAC were less clear due to ambiguous results of a field and a parallel laboratory study. Both kinds of AC significantly reduced biota to soil accumulation factors (BSAFs) of PAHs in earthworms and plants. The GAC reduced the BSAFs of earthworms by an average of 47 ± 44% and the PAC amendment reduced them by 72 ± 19%. For the investigated plants the BSAFs were reduced by 46 ± 36% and 53 ± 22% by the GAC and PAC, respectively.     

Recreational System Optimization to Reduce Conflict on Public Lands

In response to federal administrative rule, the Tahoe National Forest (TNF), California, USA engaged in trail-route prioritization for motorized recreation (e.g., off-highway-vehicles) and other recreation types. The prioritization was intended to identify routes that were suitable and ill-suited for maintenance in a transportation system. A recreational user survey was conducted online (n?=?813) for user preferences for trail system characteristics, recreational use patterns, and demographics. Motorized trail users and non-motorized users displayed very clear and contrasting preferences for the same system. As has been found by previous investigators, non-motorized users expressed antagonism to motorized use on the same recreational travel system, whereas motorized users either supported multiple-use routes or dismissed non-motorized recreationists' concerns. To help the TNF plan for reduced conflict, a geographic information system (GIS) based modeling approach was used to identify recreational opportunities and potential environmental impacts of all travel routes. This GIS-based approach was based on an expert-derived rule set. The rules addressed particular environmental and recreation concerns in the TNF. Route segments were identified that could be incorporated into minimal-impact networks to support various types of recreation. The combination of potential impacts and user-benefits supported an optimization approach for an appropriate recreational travel network to minimize environmental impacts and user-conflicts in a multi-purpose system.     

Effects of Operating Variables on PAH Emissions and Mutagenicity of Emissions from Woodstoves

As part of the Integrated Air Cancer Project, the U.S. Environmental Protection Agency (EPA) has conducted field emission measurement programs in Raleigh, North Carolina, and Boise, Idaho, to identify the potential mutagenic Impact of residential wood burning and motor vehicles on ambient and indoor air. These studies included the collection of emission samples from chimneys serving wood burning appliances. Parallel projects were undertaken in Instrumented woodstove test laboratories to quantify woodstove emissions during operations typical of in-house usage but under more controlled conditions.

Three woodstoves were operated In test laboratories over a range of burnrates, burning eastern oak, southern yellow pine, or western white pine. Two conventional stoves were tested at an altitude of 90 m. One of the conventional stoves and a catalytic stove were tested at an altitude of 825 m.

Decreasing burnrate increased total paniculate emissions from the conventional stoves while the catalytic stove's total particulate emissions were unaffected. There was no correlation of total particulate emissions with altitude whereas total polynuclear aromatic hydrocarbon (PAH) emissions were higher at the lower altitude. Mutagenicity of the catalytic stove emissions was higher than emissions from the conventional stove. Emissions from burning pine were more mutagenic than emissions from oak.     

Measurement of Organic Acids,Aldehydes, and Ketones in Residential Environments and Their Relation to Ozone

Abstract

Ozone and several polar volatile organic compounds (VOCs) including organic acids and carbonyls (aldehydes and ketones) were measured over an approximately 24 hour period in four residences during the winter of 1993 and in nine residences during the summer of 1993. All residences were in the greater Boston, Massachusetts area. The relation of the polar VOCs to the ozone concentration was examined. Indoor carbonyl concentrations were similar between the summer and winter, with the total mean winter concentration being 31.7 ppb and the total mean summer concentration being 36.6 ppb. However, the average air exchange rate was 0.9 hr^?1 during the winter and 2.6 hr^?1 during the summer. Therefore, the estimated carbonyl emission rates were significantly higher during the summer. Indoor organic acid concentrations were about twice as high during the summer as during the winter. For formic acid, the indoor winter mean was 9.8 ppb, and the summer indoor mean was 17.8 ppb. For acetic acid, the indoor winter mean was 15.5 ppb, and the summer indoor mean was 28.7 ppb. The concentrations of the polar VOCs were found to be significantly correlated with one another. Also, the emission rates of the polar VOCs were found to be correlated with both the environmental variables such as temperature and relative humidity and the ozone removal rate; however, it was difficult to apportion the relative effects of the environmental variables and the ozone removal.     

Tissue heavy metal concentrations of stranded California sea lions (Zalophus californianus) in Southern California

Concentrations of nine heavy metals (As, Cd, Cu, Fe, Hg, Pb, Mn, Mo and Zn) were determined in the hepatic and renal tissues of 80 stranded California sea lions (Zalophus californianus). Significant age-dependant increases were observed in liver and kidney concentrations of cadmium and mercury, and renal zinc concentrations. Hepatic iron concentrations were significantly higher in females than males. Animals with suspected domoic acid associated pathological findings had significantly higher concentrations of liver and kidney cadmium; and significantly higher liver mercury concentrations when compared to animals classified with infectious disease or traumatic mortality. Significantly higher hepatic burdens of molybdenum and zinc were found in animals that died from infectious diseases. This is the largest study of tissue heavy metal concentrations in California sea lions to date. These data demonstrate how passive monitoring of stranded animals can provide insight into environmental impacts on marine mammals.     

An investigation of inorganic antimony species and antimony associated with soil humic acid molar mass fractions in contaminated soils

The presence of antimony compounds is often suspected in the soil of apple orchards contaminated with lead arsenate pesticide and in the soil of shooting ranges. Nitric acid (1M) extractable Sb from the shooting range (8300 microg kg(-1)) and the apple orchard (69 microg kg(-1)) had considerably higher surface Sb levels than the control site (<1.5 microg kg(-1)), and Sb was confined to the top approximately 30 cm soil layer. Sb(V) was the principal species in the shooting range and the apple orchard surface soils. Size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) analysis of humic acids isolated from the two contaminated soils demonstrated that Sb has complexed to humic acid molar mass fractions. The results also indicate that humic acids have the ability to arrest the mobility of Sb through soils and would be beneficial in converting Sb(III) to a less toxic species, Sb(V), in contaminated areas.     

Comparing domestic versus imported apples: A focus on energy use

GOAL, SCOPE AND BACKGROUND: The issue of whether food miles are a relevant indicator for the environmental impacts associated with foods has received significant attention in recent years. It is suggested here that issues other than the distance travelled need to be considered. The argument is presented by illustrating the case for the provision of apples. MATERIALS AND METHODS: The effects of variability in primary energy requirements for apple cultivation and for other life cycle stages, seasonality (timing of consumption) and loss of produce during storage are studied in this paper, by comparing apples from different supplier countries for consumption in Europe. RESULTS: Data sources for primary energy use (PEU) of apple production are identified ranging from 0.4-3.8 MJ/kg apples for European and Southern American countries and 0.4-0.7 MJ/kg for New Zealand. This variability is related to different yields and producer management practices in the different countries. Storage loss may range from 5% to 40% for storage periods between 4 and 10 months, and this has a significant effect on the results (e.g. increasing the total PEU by 8-16% when stored for 5-9 months in Europe as compared with a no loss and no storage situation). The storage periods and related storage losses change markedly through the year for imported (i.e. non-European) versus European apples. DISCUSSION: The timing of consumption and related storage losses need to be included in the assessment, as this affects the order of preference for locally sourced versus imported apples. The variability in energy requirements in different life cycle stages, but particularly for the fruit production stage, is also significant in this comparative analysis. CONCLUSIONS: Overall, it seems that there are similarities in the total PEU ranges for European and New Zealand apples during the Southern Hemisphere's apple season (European spring and summer). However, during the European autumn and winter (Northern Hemisphere apple season) PEU values are generally higher for apples imported from the Southern Hemisphere compared with European apples consumed in Europe. However, this latter observation may not hold true where apples for consumption in one European country are imported from another European country, because energy use for road transportation has a significant influence on the result. RECOMMENDATIONS AND PERSPECTIVES: Future studies comparing alternative sources of fresh produce need to account for ranges of data for the fruit production and storage stages, which reflect the seasonality of production.     

A roadmap for carbon capture and storage in the UK

Carbon capture and storage (CCS) technology has been endorsed by the IPCC and the UK government as a key mitigation option but remains on the cusp of wide-scale commercial deployment. Here we present a technology roadmap for CCS, depicted in terms of external factors and short- and long-term pathways for its development, moving from a demonstration to commercialisation era. The roadmap was been developed through a two-phase process of stakeholder engagement; the second phase of this, a high level stakeholder workshop, is documented here. This approach has provided a unique overview of the current status, potential and barriers to CCS deployment in the UK. In addition to the roadmap graphics and more detailed review, five consensus conclusions emerging from the workshop are presented. These describe the need for a monetary CO₂ value and the financing of carbon capture and storage schemes; the lack of technical barriers to the deployment of demonstration scale CCS plant; the role of demonstration projects in developing a robust regulatory framework; key storage issues; the need for a long-term vision in furthering both the technical and non-technical development of CCS.     

Wellbore integrity analysis of a natural CO2 producer

Long-term integrity of existing wells in a CO₂-rich environment is essential for ensuring that geological sequestration of CO₂ will be an effective technology for mitigating greenhouse gas-induced climate change. The potential for wellbore leakage depends in part on the quality of the original construction as well as geochemical and geomechanical stresses that occur over its life-cycle. Field data are essential for assessing the integrated effect of these factors and their impact on wellbore integrity, defined as the maintenance of isolation between subsurface intervals. In this report, we investigate a 30-year-old well from a natural CO₂ production reservoir using a suite of downhole and laboratory tests to characterize isolation performance.These tests included mineralogical and hydrological characterization of 10 core samples of casing/cement/formation, wireline surveys to evaluate well conditions, fluid samples and an in situ permeability test. We find evidence for CO₂ migration in the occurrence of carbonated cement and calculate that the effective permeability of an 11′-region of the wellbore barrier system was between 0.5 and 1 milliDarcy. Despite these observations, we find that the amount of fluid migration along the wellbore was probably small because of several factors: the amount of carbonation decreased with distance from the reservoir, cement permeability was low (0.3–30 microDarcy), the cement–casing and cement-formation interfaces were tight, the casing was not corroded, fluid samples lacked CO₂, and the pressure gradient between reservoir and caprock was maintained. We conclude that the barrier system has ultimately performed well over the last 3 decades. These results will be used as part of a broader effort to develop a long-term predictive simulation tool to assess wellbore integrity performance in CO₂ storage sites.