Dispersion of Traffic and Space Heating Emissions In Urban Settings

A long-term dispersion model is presented for traffic and space heating emissions in urban areas, allowing fast assessment of the spatial-averaged and center-maximum pollutant concentrations.

The assumption of study areas with circular shape and normal emissions density profiles is made for the purpose of streamlining model inputs with the inventory data normally available. In addition, the rather typical assumptions of Gaussian dispersion, narrow plume, flat or gently rolling terrain, homogeneous wind field and nonreactive pollutants are made. Values of σz from Briggs correlation are used with an initial value of 30 to account for building effects.

Meterological data inputs are reduced to six parameters, inventory data inputs to two, while computations are simplified to a degree that use of a digital computer is not required.

The model is well suited to yield separate assessments for individual types of sources and control measures, as well as to reveal sensitivities from parameters such as city size, or emission density levels and distribution patterns. Its predictions are virtually identical to those of the CDM-2 UNAPMAR model for study areas with circular shape and normal emissions density profiles, and as results do not appear overly sensitive to shape and distribution patterns, the model is believed to be valid for most urban areas.     

Regulatory Off-Gas Analysis from the Evaporation of Hanford Simulated Waste Spiked with Organic Compounds

Abstract

After strontium/transuranics removal by precipitation followed by cesium/technetium removal by ion exchange, the remaining low-activity waste in the Hanford River Protection Project Waste Treatment Plant is to be concentrated by evaporation before being mixed with glass formers and vitrified. To provide a technical basis to permit the waste treatment facility, a relatively organic-rich Hanford Tank 241-AN-107 waste simulant was spiked with 14 target volatile, semi-volatile, and pesticide compounds and evaporated under vacuum in a bench-scale natural circulation evaporator fitted with an industrial stack off-gas sampler at the Savannah River National Laboratory. An evaporator material balance for the target organics was calculated by combining liquid stream mass and analytical data with off-gas emissions estimates obtained using U.S. Environmental Protection Agency (EPA) SW-846 Methods. Volatile and light semi-volatile organic compounds (<220 °C BP, >1 mm Hg vapor pressure) in the waste simulant were found to largely exit through the condenser vent, while heavier semi-volatiles and pesticides generally remain in the evaporator concentrate. An OLI Environmental Simulation Program (licensed by OLI Systems, Inc.) evaporator model successfully predicted operating conditions and the experimental distribution of the fed target organics exiting in the concentrate, condensate, and off-gas streams, with the exception of a few semi-volatile and pesticide compounds. Comparison with Henry's Law predictions suggests the OLI Environmental Simulation Program model is constrained by available literature data.     

Effects of copper deficiency and copper toxicity on organogenesis and some physiological and biochemical responses of Scots pine (Pinus sylvestris L.) seedlings grown in hydroculture

The morphological, physiological, and biochemical parameters of 6-week-old seedlings of Scots pine (Pinus sylvestris L.) were studied under deficiency (1.2 nM) and chronic exposure to copper (0.32, 1, 2.5, 5, and 10 μM CuSO₄) in hydroculture. The deposit of copper in the seed allowed the seedlings to develop under copper deficiency without visible disruption of growth. The high sensitivity of Scots pine to the toxic effects of copper was shown, which manifested as a significant inhibition of growth and development. The loss of dominance of the main root and a strong inhibition of lateral root development pointed to a lack of adaptive reorganization of the root system architecture under copper excess. A preferential accumulation of copper in the root and a minor translocation in aerial organs confirmed that Scots pine belongs to a group of plants that exclude copper. Selective impairment in the absorption of manganese was discovered, under both deficiency and excess of copper in the nutrient solution, which was independent of the degree of development of the root system. Following 10 μM CuSO₄ exposure, the absorption of manganese and iron from the nutrient solution was completely suppressed, and the development of seedlings was secured by the stock of these micronutrients in the seed. The absence of signs of oxidative stress in the seedling organs was shown under deficiency and excess of copper, as evidenced by the steady content of malondialdehyde and 4-hydroxyalkenals. Against this background, no changes in total superoxide dismutase activity in the organs of seedlings were revealed, and the increased content of low-molecular-weight antioxidants was observed in the roots under 1 μM and in the needles under 5 μM CuSO₄ exposures.

     

Radioecological impacts of tin mining

The tin mining activities in the suburbs of Jos, Plateau State, Nigeria, have resulted in technical enhancement of the natural background radiation as well as higher activity concentrations of primordial radionuclides in the topsoil of mining sites and their environs. Several studies have considered the radiological human health risks of the mining activity; however, to our knowledge no documented study has investigated the radiological impacts on biota. Hence, an attempt is made to assess potential hazards using published data from the literature and the ERICA Tool. This paper considers the effects of mining and milling on terrestrial organisms like shrubs, large mammals, small burrowing mammals, birds (duck), arthropods (earth worm), grasses, and herbs. The dose rates and risk quotients to these organisms are computed using conservative values for activity concentrations of natural radionuclides reported in Bitsichi and Bukuru mining areas. The results suggest that grasses, herbs, lichens, bryophytes and shrubs receive total dose rates that are of potential concern. The effects of dose rates to specific indicator species of interest are highlighted and discussed. We conclude that further investigation and proper regulations should be set in place in order to reduce the risk posed by the tin mining activity on biota. This paper also presents a brief overview of the impact of mineral mining on biota based on documented literature for other countries.     

An Experiment with Forced Oxygenation of the Deepwater of the Anoxic By Fjord,Western Sweden

In a 2.5-year-long environmental engineering experiment in the By Fjord, surface water was pumped into the deepwater where the frequency of deepwater renewals increased by a factor of 10. During the experiment, the deepwater became long-term oxic, and nitrate became the dominating dissolved inorganic nitrogen component. The amount of phosphate in the water column decreased by a factor of 5 due to the increase in flushing and reduction in the leakage of phosphate from the sediments when the sediment surface became oxidized. Oxygenation of the sediments did not increase the leakage of toxic metals and organic pollutants. The bacterial community was the first to show changes after the oxygenation, with aerobic bacteria also thriving in the deepwater. The earlier azoic deepwater bottom sediments were colonized by animals. No structural difference between the phytoplankton communities in the By Fjord and the adjacent Havsten Fjord, with oxygenated deepwater, could be detected during the experiment.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0524-9) contains supplementary material, which is available to authorized users.     

Dioxins (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-furans) in traditional clay products used during pregnancy

Geophagy, the practice of consuming clay or soil, is encountered among pregnant women in Africa, Eastern Asia and Latin America, but also in Western societies. However, certain types of clay are known to contain high concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The aim of this study was to determine the PCDD/F contents of orally consumed clays purchased from Dutch and African markets. Congener patterns were compared with those of pooled human milk samples collected in eight African countries, to investigate a possible relationship with clay consumption. From the Dutch market thirteen clay products were examined, seven of African and six of Suriname origin. From seven African countries, twenty clay products were collected. All 33 clay products were screened with a cell-based bioassay and those showing a high response were analyzed by GC/HRMS. High PCDD/F concentrations were measured in three clay products from the Dutch market, ranging from 66 to 103 pg TEQ g^-1, whereas clay products from African countries were from 24 to 75 pg TEQ g^-1. Patterns and relatively high concentrations of PCDD/Fs in human milk samples from the Democratic Republic of the Congo and Côte d’Ivoire suggest a relationship with the consumption of contaminated clay. Frequent use of PCDD/F contaminated clay products during pregnancy may result in increased exposure of the mother and subsequently the developing fetus and new-born child. The use of these contaminated clays during pregnancy should be carefully considered or even discouraged.     

Cobalt-induced hormonal and intracellular alterations in rat ovarian fragments in vitro

The objective of this in vitro study was to examine dose-dependent changes in the secretion activity (progesterone, 17β-estradiol and insulin-like growth factor-I) of rat ovarian fragments after experimental cobalt (Co) administration including the apoptotic potential of Co on rat ovarian fragments by evaluating the expression of apoptotic markers Bax and caspase-3. Ovarian fragments were incubated with cobalt sulphate (CoSO₄.7H₂O) at the doses 90, 170, 330 and 500 μg.mL^?1 for 24 h and compared with control group without Co addition. Release of progesterone (P₄) 17β-estradiol and insulin-like growth factor-I (IGF-I) by ovarian fragments was assessed by RIA, expression of Bax and caspase-3 by SDS-PAGE and Western blotting. Observations show that P₄ release by ovarian fragments was significantly (P < 0.05) inhibited after cobalt sulphate addition at higher doses 170–500 μg.mL^?1 used in the study in comparison to control. However, cobalt sulphate addition did not cause any significant change in the release of 17β-estradiol by ovarian fragments at all the doses used in the study (90–500 μg.mL^?1) in comparison to control. On the contrary, IGF-I release by ovarian fragments was significantly (P < 0.05) stimulated after cobalt sulphate addition at the lowest dose 90 μg.mL^?1 in comparison to control, while other doses did not cause any significant change. Also, addition of cobalt sulphate decreased the expression of both the apoptotic peptides Bax and caspase-3 at the higher doses 170, 330 and 500 μg.mL^?1, but not at the lowest dose 90 μg.mL^?1 used in the study. Obtained results suggest Co induced (1) inhibition in secretion of steroid hormone progesterone, (2) dose-dependent increase in the release of growth factor IGF-I, and (3) decrease in the expression of markers of apoptosis (Bax and caspase-3) of rat ovarian fragments.     

Improved SWAT Model Performance With Time-Dynamic Voronoi Tessellation of Climatic Input Data in Southern Africa1

Andersson, Jafet C.M., Alexander J.B. Zehnder, Bernhard Wehrli, and Hong Yang, 2012. Improved SWAT Model Performance with Time-Dynamic Voronoi Tessellation of Climatic Input Data in Southern Africa. Journal of the American Water Resources Association (JAWRA) 48(3): 480-493. DOI: 10.1111/j.1752-1688.2011.00627.x Abstract: In this study, we compared two approaches to obtain climatic time series for the Soil and Water Assessment Tool (SWAT), namely the conventional centroid method and time-dynamic Voronoi tessellation, and assessed the performance of SWAT in simulating discharge and smallholder maize yields in Southern Africa. Climatic time series were estimated with each method. The Voronoi method utilized all available precipitation and temperature data, but the centroid method used only 14.5 and 82.5%, respectively. After centroid processing, sub-basin time series were on average 42 and 63% incomplete, respectively. After Voronoi processing, all time series were complete. SWAT was fed with each climate dataset. Each model setup was independently calibrated and validated against discharge and maize yield. Similar model performance was obtained with both methods for yield. The root mean squared error during calibration was 0.26 and 0.27 t ha⁻¹ for the centroid and Voronoi methods, respectively (p-value: 0.80). However, daily discharge simulations improved significantly with the Voronoi method. The coefficient of determination increased from 0.24 to 0.39 in the calibration period (p-value: 9.6 × 10⁻¹³) and from 0.41 to 0.48 in the validation period (p-value: 3.1 × 10⁻³). The Voronoi method improved the simulation of the river flow regime. The largest improvements were obtained in data scarce situations, at high spatial and temporal resolution, and where the centroid method performed the worst.