Calorimetric studies on the thermal stability of methyl ethyl ketone peroxide (MEKP) formulations

The energetic decomposition of methyl ethyl ketone peroxide (MEKP) and its formulations have long been known to present a significant risk. Indeed, MEKP has the highest number of reported decomposition incidents of all organic peroxides, many of which have led to significant numbers of fatalities, injuries and damage. It is noteworthy that incidents have been reported at all stages of the product lifecycle.This paper is derived from incident-investigation work and provides a summary of serious incidents involving MEKP, followed by details of calorimetric experiments performed to investigate thermal stability of representative MEKP formulations containing varying amounts of MEKP monomer. In particular we report the wide degree of variation that exists between commercial MEKP formulations, even between materials that are of the same nominal formulation. Such variations are detectable using differential scanning calorimetry (DSC).Follow-up studies performed on a representative MEKP formulation containing MEKP monomer indicate that a risk of decomposition exists at temperatures well below the reported self-accelerating decomposition temperature (SADT) of the products. As such, the experimental results reported here suggest that lower storage temperatures (commonly recommended by manufacturers to maximise shelf life) should be considered as being essential throughout the product lifecycle to reduce the risk of accidents in storage and transportation.     

Metabolic rate throughout the annual cycle reveals the demands of an Arctic existence in great cormorants

Aquatic endotherms living in polar regions are faced with a multitude of challenges, including low air and water temperatures and low illumination, especially in winter. Like other endotherms from cold environments, Great Cormorants (Phalacrocorax carbo) living in Arctic waters were hypothesized to respond to these challenges through a combination of high daily rate of energy expenditure (DEE) and high food requirements, which are met by a high rate of catch per unit effort (CPUE). CPUE has previously been shown in Great Cormorants to be the highest of any diving bird. In the present study, we tested this hypothesis by making the first measurements of DEE and foraging activity of Arctic-dwelling Great Cormorants throughout the annual cycle. We demonstrate that, in fact, Great Cormorants have surprisingly low rates of DEE. This low DEE is attributed primarily to very low levels of foraging activity, particularly during winter, when the cormorants spent only 2% of their day submerged. Such a low level of foraging activity can only be sustained through consistently high foraging performance. We demonstrate that Great Cormorants have one of the highest recorded CPUEs for a diving predator; 18.6 g per minute submerged (95% prediction interval 13.0-24.2 g/min) during winter. Temporal variation in CPUE was investigated, and highest CPUE was associated with long days and shallow diving depths. The effect of day length is attributed to seasonal variation in prey abundance. Shallow diving leads to high CPUE because less time is spent swimming between the surface and the benthic zone where foraging occurs. Our study demonstrates the importance of obtaining accurate measurements of physiology and behavior from free-living animals when attempting to understand their ecology.     

Does iodine gas released from seaweed contribute to dietary iodine intake?

Thyroid hormone levels sufficient for brain development and normal metabolism require a minimal supply of iodine, mainly dietary. Living near the sea may confer advantages for iodine intake. Iodine (I₂) gas released from seaweeds may, through respiration, supply a significant fraction of daily iodine requirements. Gaseous iodine released over seaweed beds was measured by a new gas chromatography–mass spectrometry (GC–MS)-based method and iodine intake assessed by measuring urinary iodine (UI) excretion. Urine samples were obtained from female schoolchildren living in coastal seaweed rich and low seaweed abundance and inland areas of Ireland. Median I₂ ranged 154–905 pg/L (daytime downwind), with higher values (~1,287 pg/L) on still nights, 1,145–3,132 pg/L (over seaweed). A rough estimate of daily gaseous iodine intake in coastal areas, based upon an arbitrary respiration of 10,000L, ranged from 1 to 20 μg/day. Despite this relatively low potential I₂ intake, UI in populations living near a seaweed hotspot were much higher than in lower abundance seaweed coastal or inland areas (158, 71 and 58 μg/L, respectively). Higher values >150 μg/L were observed in 45.6% of (seaweed rich), 3.6% (lower seaweed), 2.3% (inland)) supporting the hypothesis that iodine intake in coastal regions may be dependent on seaweed abundance rather than proximity to the sea. The findings do not exclude the possibility of a significant role for iodine inhalation in influencing iodine status. Despite lacking iodized salt, coastal communities in seaweed-rich areas can maintain an adequate iodine supply. This observation brings new meaning to the expression “Sea air is good for you!”     

Measurement of environmental pollutants using passive sampling devices--a commentary on the current state of the art

Passive sampling devices have been used since the 1970s to measure time-weighted average (TWA) or equilibrium concentrations of pollutants in various environmental matrices (e.g. air, soils and sediments and water). In recent years the popularity of using such samplers has increased and the technology in now well established for the measurement of atmospheric pollutants. This sector has a long experience of using passive samplers in the short- and long-term assessment of air quality in the local environment and on a global scale (e.g. within the United Nations Stockholm Convention on the trans-boundary movement of persistent organic pollutants (POPs) where large networks of samplers on a continental scale have been established). In comparison, the use of passive samplers for monitoring the aquatic environment has been slower to take off. There has, however, been a recent research drive to develop devices for measuring the wide range of pollutants that can be found in environmental waters (e.g. ground, surface, and marine). It is now being recognised that passive samplers can play a valuable role in monitoring water quality within a legislative framework such as the European Union's Water Framework Directive (WFD). The data from these devices can be used alongside the results obtained from conventional spot or bottle sampling to improve risk assessments and to inform decisions on undertaking potentially expensive remedial actions. Such monitoring techniques may have uses within the European Registration, Evaluation, Authorisation & restriction of CHemicals (REACH) Directive and the forthcoming European Marine Strategy Directive. It is expected that the aquatic monitoring sector will follow a transition similar to that which occurred in air monitoring where data obtained from passive samplers can use used within a legal framework. There has also been increased interest in extending the role of passive samplers to both the measurement of equilibrium concentrations and investigating the movement and release of the dissolved fraction of various pollutants in the pore water of sediments and soils.     

Reasonable creatures: rights and rationalities in valuing the countryside

Debate on the economic valuation of the countryside is typically polarized between absolutist critics who would deny it any valid role and equally fervid proponents who see its techniques as the only way of integrating the environment into policy making. Such debate is structured by conflicting notions of rights, responsibilities and values, rather than by consideration of the role of technique in practical policy‐making. This paper attempts to take the debate forward and begins by examining the ways in which rights, responsibilities and values have been historically created. The techniques of economic valuation rest on particular conceptions of these, making them irreducibly political, and at the same time their results are often used to justify political decisions. Yet the proper role of technique ought to be to explore options. Provided that the sort of clarification that economic valuation offers is understood, it may, along with other types of technique, be used to open up the decision making process.     

Diving of the sea snake Pelamis platurus in the Gulf of Panamá

The horizontal movement patterns of eleven yellow-bellied sea snakes [Pelamis platurus (Linnaeus)] were determined incidentally to acoustic tracking studies of their diving behavior in the Gulf of Panamá during 1983–1985. The average speed of the snakes was 1.9 km h^-1 (range 0.3 to 7.1 km). Movement direction is influenced by phasic northsouth tidal currents and secondarily affected by combinations of factors that affect local current velocity. The velocity of diving snakes did not always agree with that observed for the surface current. Drift rate was not correlated with average or maximum dive depth, however, snakes that surfaced to breathe one or more times during a period had greater average drift rates than those that did not surface. The role of such factors as feeding, predator avoidance, thermoregulation, orientation, and the avoidance of surface turbulence are considered in a discussion of the adaptive significance of diving for P. platurus. Diving in this species may enable it to avoid surface disturbance, facilitate relative position changes within the surface drift, and contribute to various aspects of its feeding behavior.     

Zooplankton capture by two scleractinian corals,Madracis mirabilis andMontastrea cavernosa,in a field enclosure

Capture of zooplankton by scleractinian corals has been noted for several species, yet quantitative information on rates of capture and differential capture by prey taxon has been lacking. We used field enclosures to examine prey capture for two coral species,Madracis mirabilis (Duchassaing and Michelotti) andMontastrea cavernosa (Linnaeus), on the north coast of Jamaica (Discovery Bay) in November 1989, February and March 1990, and January 1992.M. mirabilis has small polyps and a branching colony morphology (high surface/volume ratio), whereasM. cavernosa has large polyps and mounding colonies (low surface/volume ratio). Corals were isolated front potential prey, then were introduced into enclosures with enhanced zooplankton concentrations for 15- to 20-min feeding periods. Corals were fixed immediately after the experiment to prevent digestion, and coelenteron contents were examined for captured zooplankton. Plankton pumps were used to sample ambient zooplankton in the enclosures near the end of each run. Selectivity and capture rates were calculated for each prey taxon in each experiment; both indices were high for relatively uncommon large prey, and low for copepods, which were often the most common items in the plankton. Sizes of zooplankton captured by both species were generally larger than those available considering all prey taxa combined, but were almost the same for both coral species, even though the corals' polyp sizes are very different. This occurred primarily because small copepods, with low capture rates, dominated most plankton samples. For specific prey species, or group of species, there were few significant differences in size between the prey available and the prey captured.M. mirabilis, with small polyps, also captured far more prey per unit coral biomass than didM. cavernosa, with much larger polyps. We hypothesize that the large differences in capture rate of prey taxa are related to escape or avoidance behavior by those potential prey, and to the mechanics of capture, rather than to any selectivity by the corals.     

Conservation and the 4 Rs,which are rescue,rehabilitation, release,and research

Vertebrate animals can be injured or threatened with injury through human activities, thus warranting their “rescue.” Details of wildlife rescue, rehabilitation, release, and associated research (our 4 Rs) are often recorded in large databases, resulting in a wealth of available information. This information has huge research potential and can contribute to understanding of animal biology, anthropogenic impacts on wildlife, and species conservation. However, such databases have been little used, few studies have evaluated factors influencing success of rehabilitation and/or release, recommended actions to conserve threatened species have rarely arisen, and direct benefits for species conservation are yet to be demonstrated. We therefore recommend that additional research be based on data from rescue, rehabilitation, and release of animals that is broader in scope than previous research and would have community support.     

Use of a physiologically based extraction test to estimate the human bioaccessibility of potentially toxic elements in urban soils from the city of Glasgow,UK

A simple, two-stage, physiologically based extraction has been applied to assess the human bioaccessibility of potentially toxic elements (PTE) in 20 urban soils from a major UK city. Chromium and iron bioaccessibilities were found to be markedly higher in the intestinal phase, whilst lead and zinc bioaccessibilities were higher in the stomach. Copper and manganese bioaccessibilities were generally similar under both extraction conditions. Principal component analysis was used to study relationships amongst bioaccessible element concentrations and land use. Distinctions could be observed between the distributions of the urban metals—copper, lead and zinc—and metals predominantly of geogenic origin, such as iron. There was no clear delineation between roadside soils and soils obtained from public parks. Bioaccessible analyte concentrations were found to be correlated with pseudototal (aqua regia soluble) analyte concentrations for all elements except iron. Results of the BCR sequential extraction did not, in general, provide a good indication of human bioaccessibility. Comparison of bioaccessible PTE concentrations with toxicological data indicated that lead is the element of greatest concern in these soils but that levels are unlikely to pose a health risk to children with average soil intake.