Organic compounds and trace metals of anthropogenic origin in sediments from Montego Bay,Jamaica: assessment of sources and distribution pathways

Surface sediments throughout Montego Bay, Jamaica were collected in 1995 and analyzed for their trace metal and trace organic contaminant content. A variety of trace metals, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, coprostanol as well as chlorinated hydrocarbons such as pesticides and polychlorinated biphenyls were detected and provide evidence for several anthropogenic inputs to the bay. Two main sources of these chemicals are the Montego River and the North Gully, the latter being more significant. Particle-associated pollutants were found to be distributed along the Montego River plume, as well as being transported by the prevailing water currents to the South-Western sections of the bay, probably through re-suspension of enriched fine sediments from the North Gully outfall area.     

Inhalation health effects of fine particles from the co-combustion of coal and refuse derived fuel

This paper is concerned with health effects from the inhalation of particulate matter (PM) emitted from the combustion of coal, and from the co-combustion of refuse derived fuel (RDF) and pulverized coal mixtures, under both normal and low NO_x conditions. Specific issues focus on whether the addition of RDF to coal has an effect on PM toxicity, and whether the application of staged combustion (for low NO_x) may also be a factor in this regard.

Ash particles were sampled and collected from a pilot scale combustion unit and then re-suspended and diluted to concentrations of 1000 μg/m³. These particles were inhaled by mice, which were held in a nose-only exposure configuration. Exposure tests were for 1 h per day, and involved three sets (eight mice per set) of mice. These three sets were exposed over 8, 16, and 24 consecutive days, respectively. Pathological lung damage was measured in terms of increases in lung permeability.

Results show that the re-suspended coal/RDF ash appeared to cause very different effects on lung permeability than did coal ash alone. In addition, it was also shown that a “snapshot” of lung properties after a fixed number of daily 1-h exposures, can be misleading, since apparent repair mechanisms cause lung properties to change over a period of time. For the coal/RDF, the greatest lung damage (in terms of lung permeability increase) occurred at the short exposure period of 8 days, and thereafter appeared to be gradually repaired. Ash from staged (low NO_x) combustion of coal/RDF appeared to cause greater lung injury than that from unstaged (high NO_x) coal/RDF combustion, although the temporal behavior and (apparent) repair processes in each case were similar. In contrast to this, coal ash alone showed a slight decrease of lung permeability after 1 and 3 days, and this disappeared after 12 days. These observations are interpreted in the light of mechanisms proposed in the literature. The results all suggest that the composition of particles actually inhaled is important in determining lung injury. Particle size segregated leachability measurements showed that water soluble sulfur, zinc, and vanadium, but not iron, were present in the coal/RDF ash particles, which caused lung permeabilities to increase. However, the differences in health effects between unstaged and staged coal/RDF combustion could not be attributed to variations in pH values of the leachate.     

Altered Soil-soil Water Interactions Inferred from Stream Water Chemistry at an Artificially Acidified Watershed at Bear Brook Watershed, Maine USA

The Bear Brook Watershed in Maine, USA is the site of a paired watershed study. West Bear (WB) catchment is being artificially acidified with 1,800 eq ha-1 y-1 of (NH4)2SO4. East Bear (EB) serves as the control. After six years of artificial acidification, volume-weighted concentrations in WB, normalized to EB, increased approximately as follows, in eq L-1 : H+, 15; Al (umoles), 50; Al (eq L-1), 100; Ca. 50; Mg. 20; Na, 10; K, 2; SO4, 120; NH4, 2; NO3, 80; HCO3 has decreased 10 eq L-1. Based on changing chemistry, several inferences can be made about soil-soil water interactions.1. Various combinations of cation pairs in stream waters from both catchments are significantly correlated on an annual basis. The strongest linear correlations (r2 typically greater than 0.5), with positive slopes, occur for Mg versus Ca. These relationships suggest soil-soil water equilibria of the type:Ca+2 + Mg-X = Mg+2 + Ca-X; KCa-Mg = ([Mg+2]/[Ca+2])/([Mg-X]/[Ca-X]) or, with assumptions:K'Ca-Mg = [Mg+2]/[Ca+2]The value of K'Ca-Mg remains relatively constant through time in both watersheds, except in WB in and after the fourth year of the manipulation of WB. Thereafter there is preferential depletion (Mg>Ca>na>K), primarily along shallow flow paths - thus altering the solid activity ratios of the exchange surfaces. In EB, base cation concentrations decline with increasing discharge (increasing H+), due to dilution and interaction with soils with lower base saturation. In WB the acidification reverses this relationship, perhaps partly because of displacement of cations by NH4 from the amendments. With progressive depletion of Ca and Mg in the quick-flow paths, concentrations start to decline at higher discharge, in spite of lower pH.2. Sulfate concentrations increased in WB to as high as 230 eq L-1 at high flow. The percentage of added SO4 leached to the stream increased to approximately 65% by the end of 1995. Thus, soils along base-flow paths adsorbed about 35% of the added SO4 in 1995.3. Aluminum concentrations in WB have increased from a pre-manipulation maximum of 10 mole/L at high flow to 60 mole/L. The relationship between Al and H+ is:Al = 0.13(H+)2 + 4.35which could result from either desorption or dissolution of Al to a 2+ specie. This relationship has been relatively constant through the manipulation. The Al/Ca molar ratio increased from pre-manipulation values of 0.1 to 0.3 to 0.8, at higher flow.4. The minimum pH in WB, achieved at highest flow, has decreased from about 5.3 to <4.7, an increase of about 15 eq H+ L-1. The increase in H+ has been approximately 2 eq L-1 yr-1. Neutralization of acidity has been initially accommodated by mobilization of Ca>Mg>Al>Na>K>H; by 1995 the neutralization involves the release of Al>Ca>Mg>NaH>K. Thus, the soils are inferred to (1) have reduced base saturation, (2) preferential proportional loss of mg over Ca, (3) increased SO4 saturation, and (4) higher exchangeable acidity.     

Polybrominated diphenyl ether levels in wild and farmed Chilean salmon and preliminary flow data for commercial transport

This pilot study documented the occurrence and levels of brominated flame retardants in the tissues of farmed and wild salmon in southern Chile. Samples of Coho salmon and rainbow trout were obtained from fish farms, rivers and lakes in the Patagonia in Aysen Region, Chile. The samples were analyzed by Gas Chromatography Negative Chemical Ionization Mass Spectrometry for the different polybrominated diphenyl ether (PBDE) congeners. Contaminants were observed in all the samples, and the congeners BDE 17, 28, 47 and 66 were observed in all both farmed and wild samples. The concentrations were higher in the farmed Coho salmon, presenting significant differences with wild salmon. The levels reached 182 pg/g wet weight (ww) vs. 120 ww. In the case of the rainbow trout, the concentrations were lower, although the congener profile was quite similar. The levels reached an average of 100 pg/g ww in the farmed fish versus 110 pg/g ww in wild fish, and no significant difference was observed between the species. In both species, the congener with the highest concentration was BDE 47. Based on this information, the BDE flow was estimated for commerce, which is a form of pollutant transport not usually considered in POP pollution studies. A preliminary estimation indicated that the quantity of PBDEs mobilized by commerce was in the order of kg, and in the case of Chile might reach almost 1 kg.     

The spatial pattern of nitrogen cycling in the Adirondack Park, New York

Maps of canopy nitrogen obtained through analysis of high-resolution, hyperspectral, remotely sensed images now offer a powerful means to make landscape-scale to regional-scale estimates of forest N cycling and net primary production (NPP). Moreover, recent research has suggested that the spatial variability within maps of canopy N may be driven by environmental gradients in such features as historic forest disturbance, temperature, species composition, moisture, geology, and atmospheric N deposition. Using the wide variation in these six features found within the diverse forest ecosystems of the 2.5 million ha Adirondack Park, New York, USA, we examined linkages among environmental gradients and three measures of N cycling collected during the 2003 growing season: (1) field survey of canopy N, (2) field survey of soil C:N, and (3) canopy N measured through analysis of two 185 x 7.5 km Hyperion hyperspectral images. These three measures of N cycling strongly related to forest type but related poorly to all other environmental gradients. Further analysis revealed that the spatial pattern in N cycling appears to have distinct inter- and intraspecific components of variability. The interspecific component, or the proportional contribution of species functional traits to canopy biomass, explained 93% of spatial variability within the field canopy N survey and 37% of variability within the soil C:N survey. Residual analysis revealed that N deposition accounted for an additional 2% of variability in soil C:N, and N deposition and historical forest disturbance accounted for an additional 2.8% of variability in canopy N. Given our finding that 95.8% of the variability in the field canopy N survey could be attributed to variation in the physical environment, our research suggests that remotely sensed maps of canopy N may be useful not only to assess the spatial variability in N cycling and NPP, but also to unravel the relative importance of their multiple controlling factors.     

Quantifying and mapping species threat abatement opportunities to support national target setting

The successful implementation of the Convention on Biological Diversity's post-2020 Global Biodiversity Framework will rely on effective translation of targets from global to national level and increased engagement across diverse sectors of society. Species conservation targets require policy support measures that can be applied to a diversity of taxonomic groups, that link action targets to outcome goals, and that can be applied to both global and national data sets to account for national context, which the species threat abatement and restoration (STAR) metric does. To test the flexibility of STAR, we applied the metric to vascular plants listed on national red lists of Brazil, Norway, and South Africa. The STAR metric uses data on species’ extinction risk, distributions, and threats, which we obtained from national red lists to quantify the contribution that threat abatement and habitat restoration activities could make to reducing species’ extinction risk. Across all 3 countries, the greatest opportunity for reducing plant species’ extinction risk was from abating threats from agricultural activities, which could reduce species’ extinction risk by 54% in Norway, 36% in South Africa, and 29% in Brazil. Species extinction risk could be reduced by a further 21% in South Africa by abating threats from invasive species and by 21% in Brazil by abating threats from urban expansion. Even with different approaches to red-listing among countries, the STAR metric yielded informative results that identified where the greatest conservation gains could be made for species through threat-abatement and restoration activities. Quantifiably linking local taxonomic coverage and data collection to global processes with STAR would allow national target setting to align with global targets and enable state and nonstate actors to measure and report on their potential contributions to species conservation.     

Commodity futures and market efficiency: A fractional integrated approach

In financial time series, persistence or inertia is a feature usually observable in absolute returns, i.e., a proxy for volatility. Moreover, asset return series should be essentially unpredictable according to the efficiency market hypothesis (EMH) in its weak form. Surprisingly, recent literature has found evidence of anti-persistence in technology stocks and commodity futures returns. Anti-persistence would be indicative of an overreaction of asset prices to incoming information.     

Experimental study of effectiveness of four radon mitigation solutions, based on underground depressurization, tested in prototype housing built in a high radon area in Spain

The present paper discusses the results of an empirical study of four approaches to reducing indoor radon concentrations based on depressurization techniques in underground sumps. The experiments were conducted in prototype housing built in an area of Spain where the average radon concentration at a depth of 1 m is 250 kBq m⁻³.Sump effectiveness was analysed in two locations: underneath the basement, which involved cutting openings into the foundation, ground storey and roof slabs, and outside the basement walls, which entailed digging a pit alongside the building exterior. The effectiveness of both sumps was likewise tested with passive and forced ventilation methods.The systems proved to be highly efficient, lowering radon levels by 91-99%, except in the solution involving passive ventilation and the outside sump, where radon levels were reduced by 53-55%. At wind speeds of over 8 m/s, however, passive ventilation across an outside sump lowered radon levels by 95% due to a Venturi effect induced drop in pressure.