Determination of brevetoxin in recent marine sediments

Harmful algal blooms (HAB) of Karenia brevis (K. brevis) produce a suite of lipid soluble polyether brevetoxins, known to cause environmental, health and economic ill effects. There is evidence that K. brevis has increased in abundance over the past 50 years, but the dataset is incomplete. The objective of this paper was to analyze sediment from an area where K. brevis blooms have occurred and investigate if these compounds are incorporated into the underlying sediment, thus potentially allowing the use of brevetoxins as an indicator of past K. Brevis blooms. The results from LC-ESI-MS-MS analyses of brevetoxin analogs detected in surficial sediments from three sites (Fort Meyers Beach [FMB], Big Hickory Pass [BHP] and Big Carlos Pass [BCP]) along the Southwest Florida coastline with prior HAB history are promising. The analogs detected from BHP sediments were PbTx-2 and PbTx-3 with values of 0.81 and 3.1 ng g(-1) dry sediment, respectively. The detected PbTx-2 from BCP was 3.6 ng g(-1) dry sediment, while the detected PbTx-3 from BCP was 9.7 ng g(-1) dry sediment. PbTx-3 was only detected at the FMB site (2.7 ng g(-1) dry sediment). The detection of brevetoxins in recent sediments where K. brevis have occurred indicates brevetoxin incorporation into marine sediments.     

Analysis of chlorothalonil and degradation products in soil and water by GC/MS and LC/MS

We present a method using gas chromatography (GC) and liquid chromatography (LC) coupled to a mass selective detector to measure concentrations of the fungicide chlorothalonil and several of its metabolites in soil and water. The methods employed solid-phase extraction using a hydrophobic polymeric phase for the isolation of analytes. In lake water, average analyte recoveries ranged from 70% to 110%, with exception of pentachloronitrobenzene that gave low recoveries (23%). The method detection limits were determined to be in the range of 1 and 0.1microg l(-1) for the LC and GC methods, respectively. In soil samples, recoveries ranged from 80% to 95% for 4-hydroxy-2,5,6-trichloroisophthalonitrile (metabolite II) and 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene (metabolite III). Limits of detection (LOD) were 0.05 and 0.02microg g(-1), respectively. Chlorothalonil and other metabolites were analyzed by GC giving recoveries ranging from 54% to 130% with LOD of 0.001-0.005microg g(-1).     

Vehicle Hydrocarbons’ Emission Characteristics Determined Using the Monte Carlo Method

Environmental Modeling & Assessment - Hydrocarbons (HCs) are products of incomplete combustion process which can occur during operation of the internal combustion engines (Flagan and Seinfeld...     

Comparison of Aquifer Sustainability Under Groundwater Administrations in Oklahoma and Texas1

Mittelstet, Aaron R., Michael D. Smolen, Garey A. Fox, and Damian C. Adams, 2011. Comparison of Aquifer Sustainability Under Groundwater Administrations in Oklahoma and Texas. Journal of the American Water Resources Association (JAWRA) 1‐8. DOI: 10.1111/j.1752‐1688.2011.00524.x Abstract: We compared two approaches to administration of groundwater law on a hydrologic model of the North Canadian River, an alluvial aquifer in northwestern Oklahoma. Oklahoma limits pumping rates to retain 50% aquifer saturated thickness after 20 years of groundwater use. The Texas Panhandle Groundwater Conservation District’s (GCD) rules limit pumping to a rate that consumes no more than 50% of saturated thickness in 50 years, with reevaluation and readjustment of permits every 5 years. Using a hydrologic model (MODFLOW), we simulated river‐groundwater interaction and aquifer dynamics under increasing levels of “development” (i.e., increasing groundwater withdrawals). Oklahoma’s approach initially would limit groundwater extraction more than the GCD approach, but the GCD approach would be more protective in the long run. Under Oklahoma rules more than half of aquifer storage would be depleted when development reaches 65%. Reevaluation of permits under the Texas Panhandle GCD approach would severely limit pumping as the 50% level is approached. Both Oklahoma and Texas Panhandle GCD approaches would deplete alluvial base flow at approximately 10% development. Results suggest periodic review of permits could protect aquifer storage and river base flow. Modeling total aquifer storage is more sensitive to recharge rate and aquifer hydraulic conductivity than to specific yield, while river leakage is most sensitive to aquifer hydraulic conductivity followed by specific yield.     

Immobilization and Encapsulation of Contaminants Using Silica Treatments: A Review

The immobilization and encapsulation of contaminants using silica treatments is an emerging technology for the management of contaminated land. This article reviews the potential of silica treatments for the management of metals, hydrocarbons, and acid mine drainage at contaminated sites; and evaluates the effects of environmental conditions on silica treatment performance. The review demonstrates the potential of silica treatments for managing contaminated land; however, a paucity of research offers only a limited understanding of this technology. Further development of the technology will require additional research evaluating its long‐term performance under a range of environmental conditions. Field‐based experiments and studies investigating potential adverse effects of silica treatments are also necessary to demonstrate the safety, efficacy, and reliability of silica treatments. © 2013 Wiley Periodicals, Inc.     

Development of a Dynamic Pharmacokinetic Model to Estimate Bioconcentration of Xenobiotics in Earthworms

A simple and dynamic pharmacokinetic model was developed to predict bioconcentration of organic contaminants in earthworms. The model was parameterized experimentally by placing Lumbricus terrestris in soil contaminated with 200 μg/cm² of malathion. The toxicokinetics of malathion uptake, depuration, and degradation in soil is measured. After parameterization, the model was able to accurately predict the bioconcentration factor of malathion at steady state. Sensitivity analyses were performed and the rate of absorption was determined to be the most sensitive parameter. Varying the rate of malathion elimination from earthworm tissues, malathion degradation, and the amount of malathion applied to the soil by 25-fold did not result in the bioconcentration of malathion. An increase in the rate of malathion absorption into earthworm tissues by 25-fold did result in bioconcentration. Previously published pharmacokinetic studies on xenobiotics with log K _ow values ranging up to 8.05 were used to test the predictive capacity of the model. The model was able to predict from 83% to 105% of the experimentally derived bioconcentration factors.     

Assessing energy use and greenhouse gas emission savings from compact housing: a small-town case study

Data from the US Department of Energy show that single-family detached homes consume about 17% more energy per year than attached homes and roughly double that of units in large multi-family structures. While greater use of these compact housing types could reduce a community's energy use and greenhouse gas (GHG) emissions, most local climate action plans (CAPs) do not quantify those potential savings. This article describes how the climate action planning process in the Town of Blacksburg, Virginia has addressed residential sector GHG emissions and demonstrates a methodology applied in that community for estimating potential GHG reductions from compact housing. It finds that in an aggressive compact housing scenario GHG emissions from new housing could be decreased by as much as 36%, without factoring in additional energy conservation or efficiency measures. The article concludes with a discussion of the opportunities and challenges related to implementing compact housing in future residential development.     

Clostridia dominate 16S rRNA gene libraries prepared from the hindgut of temperate marine herbivorous fishes

Bacterial diversity in the microbial communities of posterior gut sections of three temperate marine herbivorous fish species from New Zealand was characterised using Amplified Ribosomal DNA Restriction Analysis, and 16S rRNA gene amplification and sequencing methods. The fish were collected in 1999–2000 in the Hauraki Gulf, New Zealand (35°54’–36°24’S, 174°48’–175°25’E). The gastrointestinal bacterial communities of Kyphosus sydneyanus (Günther, 1886) (F. Kyphosidae), Odax pullus (Forster in Bloch and Schneider, 1801) (F. Labridae) and Aplodactylus arctidens Richardson, 1839 (F. Aplodactylidae) were dominated by five clades of bacteria, four of which belong to recognized clostridial clusters. The clone libraries of K. sydneyanus and O. pullus contained sequences from most of these clades, but were dominated by members of clostridial clusters XI and XIVa, respectively. The clone library of A. arctidens was dominated by members of clostridial cluster XIVb and an unassigned cluster containing Eubacterium desmolans and Papillibacter cinnaminovorans. The finding that strains of Firmicutes dominated the gastrointestinal microbial communities of all three fish species is consistent with the results of similar studies on terrestrial vertebrate herbivores. This work thus contributes to the view that gastrointestinal symbionts in some marine herbivorous fishes may play a similar role to those in terrestrial vertebrate herbivores studied to date.     

Errant corporations, diffuse responsibilities, and the environment: ethical issues in the Orica case study

The papers in this volume deal with various aspects of the HCB legacy at the Orica plant at Botany. Whether explicitly or implicitly, they are concerned with questions of ethics; with the just distribution of burdens and benefits; with just processes for disposing of dangerous industrial waste; and with a just custodianship of the Botany environment. These ethical issues illustrate the difficulty of securing corporate accountability, and the elusiveness of responsibility within organisations. This paper reflects on some of the issues for ethics raised by the Orica case and their significance for corporate ethics.     

Assessment of metal contamination using X-ray fluorescence spectrometry and the toxicity characteristic leaching procedure (TCLP) during remediation of a waste disposal site in Antarctica

The remediation of the Thala Valley landfill, Casey Station, East Antarctica, is part of efforts to clean-up contaminated sites associated with the Australian Antarctic Program. These sites, ranging from abandoned rubbish dumps to fuel spills, are contaminated principally with metals and petroleum hydrocarbons. Remediation success depends on accurate, cost-effective and timely--fit-for-purpose--chemical analysis of soil and water samples from the site, which is required to guide excavation, the in situ or off-site treatment and disposal of contaminated material, and to validate satisfactory remediation. Owing to the remote location of Antarctica, it is necessary to carry out chemical analyses on-site. Waste and soil contaminated with Pb, Zn, Cd, and Cu were excavated from Thala Valley for removal to Australia, treatment and disposal. Analysis of total metal concentrations in soil was performed at Casey Station with a transportable energy dispersive X-ray fluorescence (EDXRF) spectrometer. Soil samples were prepared using a simple size-fractionation method to expedite sample throughput. A method for assessing contaminant mobility in solid waste (toxicity characteristic leaching procedure, TCLP) was also used to characterise soil. Although this was more labour-intensive and time-consuming than the total metals analysis, it was of great utility because leachable metals were often significant determinants in the assessment of contaminated soil. The combined data helped managers during remediation, directing excavation and allowing waste to be classified for treatment and disposal before its return to Australia.