Biomonitoring of contaminated mine tailings through age accumulation of trace metals in the bank vole (Clethrionomys glareolus)

Lead, zinc and cadmium were determined in a range of tissues from laboratory-bred bank voles (Clethrionomys glareolus) exposed to elevated levels of dietary zinc (124 micrograms g-1). The pelletised diet was derived from vegetation harvested from the surface of a revegetated tailings dam at a modern Zn-Pb mine. Exposure regimes to the contaminated diet were 16, 32, 64, 128 or 256 days. Elevated levels of dietary zinc were not reflected in the individual tissue or total body concentrations. Marginal age accumulation of lead and cadmium was evident in the liver (Pb) and kidney (Pb and Cd). Tissue residues did not attain toxicologically significant concentrations. Animals inhabiting the grassland are considered to be at low ecotoxicological risk with respect to trace metals.     

Effects of low concentrations of herbicides on full-season, field-grown potatoes

Current phytotoxicity plant test protocols for US pesticide registration require testing for effects on seedling emergence and early growth without regard to other important factors, such as plant reproduction. Yield and quality reduction can have significant economic and ecological effects. Therefore, field trials were conducted to determine if potato (Solanum tubersum L.) vegetative growth and tuber yield and quality were affected by herbicides at below recommended field rates. Potatoes were grown in fields at the Oregon State University Horticulture Farm with herbicides applied at below recommended field application rates 14 d after emergence (DAE) or at 28 DAE. Plant height was measured before and 14 d after application. Visual foliar injury was rated 14 d after application, and tuber yield and quality parameters were measured at harvest (120 DAE). Some tubers were grown in the greenhouse the following year to determine if there were carry-over effects. Potato vegetation and tuber yield quality were generally more affected by herbicides applied at 14 DAE than at 28 DAE. Tuber yield and quality parameters were more affected by lower herbicide rates than were plant height or injury. There were significant yield losses caused by low rates of sulfometuron methyl and imazapyr and, to a lesser extent, with glyphosate and cloransulam-methyl. Bromoxynil and MCPA ((4-chloro-2-methylphenoxy)acetic) acid had little effect on the plants. Vegetative responses did not accurately predict yield and quality responses of tubers; therefore, reproductive responses should be considered in phytotoxicity test protocols for pesticide registration in the USA.     

Comparison of in vivo and in vitro methodologies for the assessment of arsenic bioavailability in contaminated soils

An in vivo swine assay was utilised for the determination of arsenic (As) bioavailability in contaminated soils. Arsenic bioavailability was assessed using pharmacokinetic analysis encompassing area under the blood plasma-As concentration time curve following zero correction and dose normalisation. In contaminated soil studies, As uptake into systemic circulation was compared to an arsenate oral dose and expressed as relative As bioavailability. Arsenic bioavailability ranged from 6.9+/-5.0% to 74.7+/-11.2% in 12 contaminated soils collected from former railway corridors, dip sites, mine sites and naturally elevated gossan soils. Arsenic bioavailability was generally low in the gossan soils and highest in the railway soils, ranging from 12.1+/-8.5% to 16.4+/-9.1% and 11.2+/-4.7% to 74.7+/-11.2%, respectively. Comparison of in vivo and in vitro (Simplified Bioaccessibility Extraction Test [SBET]) data from the 12 contaminated soils and bioavailability data collected from an As spiked soil study demonstrated that As bioavailability and As bioaccessibility were linearly correlated (in vivo As bioavailability (mgkg(-1))=14.19+0.93.SBET As bioaccessibility (mgkg(-1)); r(2)=0.92). The correlation between the two methods indicates that As bioavailability (in vivo) may be estimated using the less expensive, rapid in vitro chemical extraction method (SBET) to predict As exposure in human health risk assessment.     

Associations of Forest Cover,Fragment Area,and Connectivity with Neotropical Understory Bird Species Richness and Abundance

Theoretical and empirical studies demonstrate that the total amount of forest and the size and connectivity of fragments have nonlinear effects on species survival. We tested how habitat amount and configuration affect understory bird species richness and abundance. We used mist nets (almost 34,000 net hours) to sample birds in 53 Atlantic Forest fragments in southeastern Brazil. Fragments were distributed among 3 10,800‐ha landscapes. The remaining forest in these landscapes was below (10% forest cover), similar to (30%), and above (50%) the theoretical fragmentation threshold (approximately 30%) below which the effects of fragmentation should be intensified. Species‐richness estimates were significantly higher (F= 3715, p = 0.00) where 50% of the forest remained, which suggests a species occurrence threshold of 30–50% forest, which is higher than usually occurs (<30%). Relations between forest cover and species richness differed depending on species sensitivity to forest conversion and fragmentation. For less sensitive species, species richness decreased as forest cover increased, whereas for highly sensitive species the opposite occurred. For sensitive species, species richness and the amount of forest cover were positively related, particularly when forest cover was 30–50%. Fragment size and connectivity were related to species richness and abundance in all landscapes, not just below the 30% threshold. Where 10% of the forest remained, fragment size was more related to species richness and abundance than connectivity. However, the relation between connectivity and species richness and abundance was stronger where 30% of the landscape was forested. Where 50% of the landscape was forested, fragment size and connectivity were both related to species richness and abundance. Our results demonstrated a rapid loss of species at relatively high levels of forest cover (30–50%). Highly sensitive species were 3‐4 times more common above the 30–50% threshold than below it; however, our results do not support a unique fragmentation threshold. Asociaciones de la Cobertura Forestal, Superficie del Fragmento y Conectividad con la Riqueza y Abundancia de Aves Neotropicales de Sotobosque     

Comments on the NAS Report: Odors From Stationary and Mobile Sources

ABSTRACT

Solid phase microextraction (SPME) presents many advantages over conventional analytical methods by combining sampling, preconcentration, and direct transfer of the analytes into a standard gas chromatograph (GC). Since its commercial introduction in the early 1990s, SPME has been successfully applied to the sampling and analysis of environmental samples. This paper presents an overview of the current methods for air sampling and analysis with SPME using both grab and time-weighted average (TWA) modes. Methods include total volatile organic compounds (TVOCs), formaldehyde, and several target volatile organic compounds (VOCs). Field sampling data obtained with these methods in indoor air were validated with conventional methods based on sorbent tubes. The advantages and challenges associated with SPME for air sampling are also discussed. SPME is accurate, fast, sensitive, versatile, and cost-efficient, and could serve as a powerful alternative to conventional methods used by the research, industrial, regulatory, and academic communities.     

Species composition,community structure and zoogeography of fishes of mangrove estuaries in the Solomon Islands

Mangrove estuaries in the Solomon Islands are well developed, but are small and isolated from each other by extensive fringing coral reef lagoons. A total of 136 species of fish were recorded from 13 estuaries (6 estuaries in Kolombangara, 3 in New Georgia, 3 in Rendova and 1 in the Florida Group); none contained more than 50 species. Sampling took place during five 3 wk expeditions from 1986 to 1988. The mean biomass of 11.60 g m^–2 is comparable with that of similar estuaries in northern Australia. Cluster-analysis revealed two patterns of fish species composition. The first group, in which Gobiidae were the most numerous taxon, inhabited soft, muddy-bottom estuaries. The second group, dominated by Pomacentridae, lived in hard-bottom, log-strewn estuaries. The role of the estuaries as nursery grounds for coral reef species was assessed and found to be insignificant, but they are used as feeding grounds by mobile piscivorous species. The species composition of Solomon Island estuaries was compared with that of other Indo-Pacific estuaries. No endemic species were found and the fauna is typical of such mangrove systems throughout the region. However, several taxa that are common in Australia or New Guinea were not found, notably Ariidae, Centropomidae,Pomadasys, and Sciaenidae. These absentees, and the fish fauna as a whole, are discussed in relation to the position of the Solomon Islands at the western edge of the Pacific Plate, the effects of deep-ocean trenches, the recent geological origin of the islands, and possible methods of colonisation from nearby mangroves in Australia and New Guinea. The importance of larval durations and dispersal to colonisation are discussed in relation to oceanic circulation patterns in the Solomon Sea.     

The impact of the Gulf crisis on Qatar's humanitarian sector

The 2017 Gulf crisis is one of the most challenging episodes faced by Qatar since its independence in 1971, with major economic, social, and political impacts on the Arab Gulf nation. Its economic prognosis has been brought into doubt, the map of regional alliances has been redrawn, and any prospects of deeper regional integration have been dashed. This paper analyses the little-documented impact of the crisis on Qatar's humanitarian sector, which has unfolded as the small, gas-rich emirate has striven to become a major humanitarian donor. It concludes that while there have been disruptions to humanitarian operations and regional coordination, the Gulf crisis has triggered and in some cases accelerated already intended reforms across the Qatari humanitarian sector. In the long term, the reorganisation and adaptation implemented to weather the storm of the crisis may help Qatar to emerge from the crisis with a more sustainable and resilient humanitarian sector.     

Principles and application of an in vivo swine assay for the determination of arsenic bioavailability in contaminated matrices

The assessment of arsenic (As) bioavailability from contaminated matrices is a crucial parameter for reducing the uncertainty when estimating exposure for human health risk assessment. In vivo assessment of As utilising swine is considered an appropriate model for human health risk assessment applications as swine are remarkably similar to humans in terms of physiology and As metabolism. While limited in vivo As bioavailability data is available in the literature, few details have been provided regarding technical considerations for performing in vivo assays. This paper describes, with examples, surgical, experimental design and analytical issues associated with performing chronic and acute in vivo swine assays to determine As bioavailability in contaminated soil and food.     

Natural concentrations and reference values of heavy metals in sedimentary soils in the Brazilian Amazon

The soils of the Brazilian Amazon exhibit large geochemical diversity reflecting the different soil formation processes in an area covering 49% of the Brazilian territory. Soil contamination by heavy metals is one of the threats to the sustainability of this Biome but establishing quality reference values (QRVs) for the region is a challenging owing to the immense territorial area of the Amazon. This study aimed to determine the natural background of heavy metals in soils from the southwestern Brazilian Amazon in order to propose QRVs for Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, and Zn for alluvial sedimentary soils. One hundred and twenty-eight soil samples were collected at a depth of 0.0–0.2 m in sites with minimal anthropogenic interference. Soil sample digestion was based on the EPA 3051A method and metal concentrations were determined by ICP-OES. QRVs calculated for the southwestern Brazilian Amazon are among the lowest recorded in Brazil (mg kg^?1): Ba (16.5), Cd (0.1), Cr (6.9), Cu (2.8), Fe (15.4), Mn (13.4), Ni (1.7), Pb (4.4), Sb (0.9), and Zn (5.7). The low metal concentration is likely a result of the sedimentary origin of the soils. The results of this study can serve as a basis for defining public policies to investigate the environmental impacts resulting from changes in land use in areas of the Brazilian Amazon.     

The Determination of Formaldehyde,Acrolein, and Low Molecular Weight Aldehydes in Industrial Emissions on a Single Collection Sample

Formaldehyde, acrolein, and low molecular weight aldehydes are collected in 1% NaHSO₃ solution in Greenberg-Smith or midget impingers from industrial effluents. Efficiency of collection is excellent when two impingers are used in series. Formaldehyde is measured in an aliquot of the collection medium by the chromo-tropic acid procedure, acrolein by a modified mercuric-chloride-hexylresorcinol procedure, and C₂-C₅ aldehydes by a gas chromatographic procedure. The method permits the analysis of all C₁-C₅ aldehydes on a single collection sample. Data on aldehyde concentrations from a variety of effluents are presented.