Analysing selected VVOCs in indoor air with solid phase microextraction (SPME): a case study

A multi-storey building with great diversity of room use was monitored after extensive renovation to remove mould growth secondary to a leaky roof. Tests for volatile organic compounds (VOC) with activated charcoal showed a successfully renovation. Solid phase microextraction (SPME) for detection of selected very volatile organic compounds (VVOCs) revealed indoor air concentrations ranging from 550 to 4,600 microg m(-3). The SPME technique also successfully detected emissions from working and building materials and documented the results of remedial measures in offices. The prior and current use of acetone, methyl acetate and 2-methylpentane within the building resulted in their elevated concentrations in other building floors.     

Polychlorinated biphenyls (PCBs) in soils of the Moscow region: concentrations and small-scale distribution along an urban-rural transect

In soils of the Moscow region, we examined PCB concentrations in bulk samples and aggregate fractions. Topsoils under grassland and forest at five locations along a southeast-bound transect from Moscow and at a northeastern background location (grassland only) were analysed. We collected aggregates >1 cm and fractionated them into interior and exterior portions and also analysed the remaining soil without the aggregates >1 cm. The concentrations of the sum of 17 PCBs (sigma17PCBs) in 35 bulk soil samples ranged from 3.1 to 42 microg kg(-1). This was 48-61% of the sigma33PCBs determined in 23 selected samples. The congeners 138(+158), 101 and 52 were most abundant. All PCB concentrations and the degree of chlorination declined with increasing distance from Moscow. The PCBs were accumulated in the aggregate exterior (on average 146% of the sigma17PCBs in bulk soil). We conclude that the ecotoxicological risk of PCBs in soils may not be properly assessed with the conventional bulk soil analysis.     

Accumulation of weathered polycyclic aromatic hydrocarbons (PAHs) by plant and earthworm species

Experiments were conducted to assess the bioavailability of polyclycic aromatic hydrocarbons (PAHs) in soil from a Manufactured Gas Plant site. Three plant species were cultivated for four consecutive growing cycles (28 days each) in soil contaminated with 36.3 microg/g total PAH. During the first growth period, Cucurbita pepo ssp. pepo (zucchini) tissues contained significantly greater quantities of PAHs than did Cucumis sativus (cucumber) and Cucurbita pepo ssp. ovifera (squash). During the first growth cycle, zucchini plants accumulated up to 5.47 times more total PAH than did the other plants, including up to three orders of magnitude greater levels of the six ring PAHs. Over growth cycles 2-4, PAH accumulation by zucchini decreased by 85%, whereas the uptake of the contaminants by cucumber and squash remained relatively constant. Over all four growth cycles, the removal of PAHs by zucchini was still twice that of the other species. Two earthworm species accumulated significantly different amounts of PAH from the soil; Eisenia foetida and Lumbricus terrestris contained 0.204 and 0.084 microg/g total PAH, respectively, but neither species accumulated measurable quantities 5 or 6 ring PAHs. Lastly, in abiotic desorption experiments with an aqueous phase of synthetically prepared organic acid solutions, the release of 3 and 4 ring PAHs from soil was unaffected by the treatments but the desorption of 5-6 ring constituents was increased by up to two orders of magnitude. The data show that not only is the accumulation of weathered PAHs species-specific but also that the bioavailability of individual PAH constituents is highly variable.     

Uptake of Cd,Pb, U,and Zn by plants in floodplain pollution hotspots contributes to secondary contamination

Environmental Science and Pollution Research - Willows, woody plants of genus Salix common in floodplains of temperate regions, act as plant pumps and translocate the Cd and Zn in the soil profiles...     

Recognize fish as food in policy discourse and development funding

The international development community is off-track from meeting targets for alleviating global malnutrition. Meanwhile, there is growing consensus across scientific disciplines that fish plays a crucial role in food and nutrition security. However, this ‘fish as food’ perspective has yet to translate into policy and development funding priorities. We argue that the traditional framing of fish as a natural resource emphasizes economic development and biodiversity conservation objectives, whereas situating fish within a food systems perspective can lead to innovative policies and investments that promote nutrition-sensitive and socially equitable capture fisheries and aquaculture. This paper highlights four pillars of research needs and policy directions toward this end. Ultimately, recognizing and working to enhance the role of fish in alleviating hunger and malnutrition can provide an additional long-term development incentive, beyond revenue generation and biodiversity conservation, for governments, international development organizations, and society more broadly to invest in the sustainability of capture fisheries and aquaculture.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01451-4) contains supplementary material, which is available to authorized users.     

Arsenic distribution and pathway scenarios for sediments and water in a peri-urban Mongolian small-scale coal mining area (Nalaikh District,Ulaanbaatar)

The distribution of arsenic (As) in environmental compartments is investigated in the Nalaikh Depression of N-Mongolia. In Nalaikh, lignite coal is mined by artisanal small-scale mining (ASM) approaches. Because As is often associated with sulfuric minerals in coal, it was hypothesized that enrichment of As is related to coal ASM. A second hypothesis considered coal combustion in power plants, and stoves are a key source of As in the local environment. Three mobilization and distribution scenarios were developed for potential As pathways in this semiarid environment. About 43 soil and 14 water sites were analyzed for As concentrations and meaningful parameters in soil and water. About 28 topsoil samples were analyzed in surface-subsurface pairs in order to identify potential eolian surface enrichment. Additionally, fluvial-alluvial sediments and geogenic and anthropogenic deposits were sampled. Water was sampled as surface water, groundwater, precipitation, and industrial water. Results show that As does not pose a ubiquitous risk in the Nalaikh Depression. However, locally and specifically in water, As concentrations may exceed the WHO guideline value for drinking water by up to a factor of 10. A carefully selected sampling strategy allows the evaluation of the distribution scenarios, which reveals a combination of (a) geogenic As in groundwater and distribution via surface water with (b) anthropogenic As redistribution via eolian pathways. An immediate linkage between As redistribution and coal mining is not evident. However, As distribution in fly ash from coal combustion in the local power plant and yurt settlements is the most likely As pathway. Hence, the results indicate the potential influence of diffuse, low-altitude sources on As emission to the environment. As such, this study provides a good example for As distribution under semiarid climate conditions influenced by geogenic and anthropogenic factors.

     

Characterization of urea SCR using Taguchi technique and computational methods

Use of biodiesel in diesel engine helps to reduce HC, CO, and smoke emissions due to their enormous oxygen content, whereas NOx emissions formed by Zeldovich mechanism shoot up. Implementation of Bharat Stage (BS) VI by April 2020 in India has created extreme pressure on automobile manufacturers to include after treatment technology in their systems. Selective catalytic reduction (SCR), a NOx control technology, is operated using aqueous urea solution as the reductant. There are several parameters that need to be monitored to enhance the NOx conversion efficiency of SCR retrofit. The uniformity index of ammonia, which determines the conversion efficiency, is greatly influenced by parameters like exhaust gas temperature, injection angle, injector position, mass flow rate, and SCR geometry. This paper considers two types of SCR design, namely SCR with and without mixer design and their impact on NOx reduction. The effect of mass flow rate on urea conversion in SCR design without mixer is 27%, but the impact is reduced greatly in SCR design with mixer with less than 2% variation. The UI resulting from different cases ranges from 0.59 to 0.83. Using Taguchi technique and CFD tool, the impact of parameters on both the SCR designs has been investigated and the optimum SCR design is reported.

     

Levels of PCB 126 and PCB 153 in plasma and tissues in goats exposed during gestation and lactation

The aim of the present study was to gain knowledge about the disposition of the PCB congeners 126 and 153 in a goat model where pregnant does were given oral doses of PCB from day 60 of gestation until delivery. The goat kids were thus exposed to PCB during gestation and lactation. The doses of PCB 153 and PCB 126 were 98 and 49 ng/kg body wt/day, respectively. PCB levels were measured in plasma from the does at day 90 of gestation and at delivery, and in plasma from the kids at birth and four weeks post partum. Concentrations of PCB were analysed in brain, liver and fat tissue from the does six weeks after delivery and in liver and fat tissue from the kids at nine months of age. The ratio of estimated body burden to ingested dose in the does, was 0.95 +/- 0.07 for PCB 153 and 0.41 +/- 0.03 for PCB 126. Approximately 9% of PCB 153 and 6% of PCB 126 was transferred from the mothers to their kids during gestation and lactation. Prenatal exposure contributed to a much lower fraction of the body burden than postnatal PCB intake via milk, due to the fact that almost 100% of the PCB 153 transferred from the does to kids was transferred via milk, and the PCB 126 intake via milk was threefold higher than the calculated body burden. The hepatic PCB 126 concentration in both does and kids was significantly higher than the concentration in fat, in contrast to PCB 153, where the highest concentrations were found in fat. A significant difference in body burden between the does at delivery, the newborn kids, and the kids at four weeks of age, did not influence the plasma concentration of PCB 153 on a fat weight basis, which showed no difference with sampling time. Our results suggest that PCB 126 and PCB 153 have different pharmacokinetic properties. The higher levels of PCB 126 in liver tissue compared to fat tissue confirm the concept of hepatic sequestration. The similar blood concentration of PCB 153 in the does at delivery and their newborn kids despite the considerable difference in body burden, suggests a high degree of placental transfer. This supports previous observations that low molecular weight, lipid-soluble, non-polar chemicals reach the fetus to the greatest possible extent. For PCB 153, the body burden may provide the appropriate dose metric at steady state, but may give a minor underestimation of PCB 126 at low environmental exposure levels due to hepatic sequestration.