Effect of water treatment residuals on soil phosphorus, copper and aluminium availability and toxicity

Water treatment residuals (WTRs) are produced by the treatment of potable water with coagulating agents. Beneficial recycling in agriculture is hampered by the fact that WTRs contain potentially toxic contaminants (e.g. copper and aluminium) and they bind phosphorus strongly. These issues were investigated using a plant bioassay (Lactuca sativa), chemical extractions and an isotopic dilution technique. Two WTRs were applied to an acidic and a neutral pH soil at six rates. Reductions in plant growth in amended soils were due to WTR-induced P deficiency, rather than Al or Cu toxicity. The release of potentially toxic Al from WTRs was found to be mitigated by their alkaline nature and pH buffering capacity. However, acidification of WTRs was shown to release more soluble Al than soil naturally high in Al. Copper availability was relatively low in all treatments. However, the lability of WTR-Cu increased when the WTR was applied to the soil.     

Determination of the insecticide diflubenzuron in mushrooms by kinetic method and high-performance liquid chromatographic method

In the present study, a new sensitive and simple kinetic-spectrophotometric method for the determination of the insecticide diflubenzuron [1-(4-chlorophenyl)-3-(2,6-diflubenzoil)urea] is proposed. The method is based on the inhibited effect of diflubenzuron on the oxidation of sulphanilic acid (SA) by hydrogen peroxide in phosphate buffer in presence Cu(II) ion. Diflubenzuron was determined with linear calibration graph in the interval from 0.31 to 3.1 μg mL?1 and from 3.1 to 31.0 μg mL?1. The optimized conditions yielded a theoretical detection limit of 0.18 μg mL?1 corresponding to 0.036 mg kg(-1)mushroom sample based on the 3S(b) criterion. The RSD is 5.03-1.83 % and 2.81-0.71 % for the concentration interval of diflubenzuron 0.31-3.1 μg mL?1 and 3.1-31.0 μg mL?1, respectively. The reaction was followed spectrophotometrically at 370 nm. The kinetic parameters of the reaction are reported, and the rate equations are suggested. The developed procedure was successfully applied to the rapid determination of diflubenzuron in spiked mushroom samples of different mushroom species. The HPLC method was used like a comparative method to verify results.     

Consequences of nitrate leaching following stem-only harvesting of Swedish forests are dependent on spatial scale

Short-term increases in soil solution nitrate (NO₃⁻) concentration are often observed after forest harvest, even in N-limited systems. We model NO₃⁻ leaching below the rooting zone as a function of site productivity. Using national forest inventories and published estimates of N attenuation in rivers and the riparian zone, we estimate effects of stem-only harvesting on NO₃⁻ leaching to groundwater, surface waters and the marine environment. Stem-only harvesting is a minor contributor to NO₃⁻ pollution of Swedish waters. Effects in surface waters are rapidly diluted downstream, but can be locally important for shallow well-waters as well as for the total amount of N reaching the sea. Harvesting adds approximately 8 Gg NO₃-N to soil waters in Sweden, with local concentrations up to 7 mg NO₃-N l⁻¹. Of that, ∼3.3 Gg reaches the marine environment. This is ∼3% of the overall Swedish N load to the Baltic.     

Potential physiological effects of pharmaceutical compounds in Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis>) implied by transcriptomic analysis

Background, aim, and scope  

Pharmaceuticals are emerging pollutants widely used in everyday urban activities which can be detected in surface, ground, and drinking waters. Their presence is derived from consumption of medicines, disposal of expired medications, release of treated and untreated urban effluents, and from the pharmaceutical industry. Their growing use has become an alarming environmental problem which potentially will become dangerous in the future. However, there is still a lack of knowledge about long-term effects in non-target organisms as well as for human health. Toxicity testing has indicated a relatively low acute toxicity to fish species, but no information is available on possible sublethal effects. This study provides data on the physiological pathways involved in the exposure of Atlantic salmon as representative test species to three pharmaceutical compounds found in ground, surface, and drinking waters based on the evaluation of the xenobiotic-induced impairment resulting in the activation and silencing of specific genes.     

Use of CALPUFF for exposure assessment in a near-field,complex terrain setting

CALPUFF is an atmospheric source-receptor model recommended by the U.S. Environmental Protection Agency for use on a case-by-case basis in complex terrain and wind conditions. The ability of the model to provide useful information for exposure assessments in areas with those topographical and meteorological conditions has received little attention. This is an important knowledge gap for use of CALPUFF outside of regulatory applications, such as exposure analyses conducted in support of risk assessments and health studies. We compared deposition of cadmium (Cd), lead (Pb), and zinc (Zn) calculated with CALPUFF as a result of emissions from a zinc smelter with corresponding concentrations of the metals measured in attic dust and soil samples obtained from the surrounding area. On a point-by-point analysis, predictions from CALPUFF explained 11% (lead) to 53% (zinc) of the variability in concentrations measured in attic dust. Levels of heavy metals in soil interpolated to 100 residential addresses from the distribution of concentrations measured in soil samples also agreed well with deposition predicted with CALPUFF: R² of 0.46, 0.76, and 079 for Pb, Cd, and Zn, respectively. Community-average concentrations of Cd, Pb, and Zn measured in soil were significantly (p < 0.0001) and strongly correlated (R² ranged from 0.77 to 0.98) with predicted deposition rates. These findings demonstrate that CALPUFF can provide reasonably accurate predictions of the patterns of long-term air pollutant deposition in the near-field associated with emissions from a discrete source in complex terrain. Because deposition estimates are calculated as a linear function of air concentrations, CALPUFF is expected to be reliable model for prediction of long-term average, near-field ambient air concentrations in complex terrain as well.     

WRF-Chem simulation of East Asian air quality: Sensitivity to temporal and vertical emissions distributions

This study develops fine temporal (seasonal, day-of-week, diurnal) and vertical allocations of anthropogenic emissions for the TRACE-P inventory and evaluates their impacts on the East Asian air quality prediction using WRF-Chem simulations in July 2001 at 30-km grid spacing against available surface measurements from EANET and NEMCC. For NO₂ and SO₂, the diurnal and vertical redistributions of emissions play essential roles, while the day-of-week variation is less important. When all incorporated, WRF-Chem best simulates observations of surface NO₂ and SO₂ concentrations, while using the default emissions produces the worst result. The sensitivity is especially large over major cities and industrial areas, where surface NO₂ and SO₂ concentrations are reduced by respectively 3–7 and 6–12 ppbv when using the scaled emissions. The incorporation of all the three redistributions of emissions simulates surface O₃ concentrations higher by 4–8 ppbv at night and 2–4 ppbv in daytime over broad areas of northern, eastern and central China. To this sensitivity, the diurnal redistribution contributes more than the other two.     

Contribution of residential wood combustion to PM10 levels in Portugal

Wood is commonly used in residential combustion for heating purposes; however, it can be a major source of air pollutants, namely fine particles, volatile organic compounds and carbon monoxide. Since 2004, the PM10 daily limit value has been surpassed in Portugal, and the European Commission has stated that plans and programs must be designed in order to reduce these levels. In Portugal, 18% of PM10 emissions are due to residential wood combustion, which may deeply impact the PM10 levels in the atmosphere. The main aim of this study is to investigate the impact of residential wood combustion on the air quality in Portugal. The air quality modelling system MM5/CHIMERE was applied over Portugal for a winter month, for the following three scenarios: the reference scenario, considering the actual emissions of PM10; scenario 1, where residential wood combustion emissions are not considered; and scenario 2, which takes into account a complete conversion from traditional fireplaces to certified appliances (with a 90% reduction in PM emissions). The residential wood combustion contribution to PM10 air quality concentration values during January 2007 ranges from 0 to 14 μg m^?3, with a mean contribution of 10 μg m^?3 in the Lisboa area and 6 μg m^?3 in the Porto region. Concerning the legislated values, the area where the daily average limit value (50 μg m^?3) is exceeded decreases by 46% in the simulation when residential combustion is not considered. The modelling results for scenario 2 are not significantly different from those for scenario 1. In summary, the regulation of the residential wood combustion sector is as an effective way to reduce the PM10 levels in the atmosphere as regards air quality plans and programs.     

Evaluation of airborne particulate matter and metals data in personal,indoor and outdoor environments using ED-XRF and ICP-MS and co-located duplicate samples

Factors and sources affecting measurement uncertainty associated with monitoring metals in airborne particulate matter (PM) were investigated as part of the Windsor, Ontario Exposure Assessment Study (WOEAS). The assessment was made using co-located duplicate samples and a comparison of two analytical approaches: ED-XRF and ICP-MS. Sampling variability was estimated using relative percent difference (RPD) of co-located duplicate samples. The comparison of ICP-MS and ED-XRF results yields very good correlations (R² ≥ 0.7) for elements present at concentrations that pass both ICP-MS and ED-XRF detection limits (e.g. Fe, Mn, Zn, Pb and Cu). PM concentration ranges (median, sample number) of 24-h indoor PM₁₀ and personal PM₁₀ filters, and outdoor PM_2.5 filters were determined to be 2.2–40.7 (11.0, n = 48) μg m^?3, 8.0–48.3 (11.9, n = 48) μg m^?3, and 17.1–42.3 (21.6, n = 18) μg m^?3, respectively. The gravimetric analytical results reveal that the variations in PM mass measurements for same-day sampling are insignificant compared to temporal or spatial variations: 92%, 100% and 96% of indoor, outdoor and personal duplicate samples, respectively, pass the quality criteria (RPD ≤ 20%). Uncertainties associated with ED-XRF elemental measurements of S, Ca, Mn, Fe and Zn for 24-h filter samples are low: 78%–100% of the duplicate samples passed the quality criteria. In the case of 24-h filter samples using ICP-MS, more elements passed the quality criteria due to the lower detection limits. These were: Li, Na, K, Ca, Si, Al, V, Fe, Mn, Co, Cu, Mo, Ag, Zn, Pb, As, Mg, Sb, Sn, Sr, Th, Ti, Tl, and U. Low air concentrations of metals (near or below instrumental detection limits) and/or inadvertent introduction of metal contamination are the main causes for excluding elements based on the pass/fail criteria. Uncertainty associated with elemental measurements must be assessed on an element-by-element basis.     

On-road traffic emissions in a megacity

A new annual bottom–up emission inventory of criteria pollutants and greenhouse gases from on-road mobile sources was developed for 2006 for the metropolitan area of Buenos Aires, Argentina, within a four-year regional project aimed at providing tools for chemical weather forecast in South America. Under the scarcity of local emission factors, we collected data from measuring campaigns performed in Argentina, Brazil, Chile and Colombia and compiled a data set of regional emission factors representative of Latin American fleets and driving conditions. The estimated emissions were validated with respect to downscaled national estimates and the EDGAR global emission database. Our results highlight the role of older technologies accounting in average for almost 80% of the emissions of all species. The area exhibits higher specific emissions than developed countries, with figures two times higher for criteria pollutants. We analyzed the effect on emissions of replacing gasoline by compressed natural gas, occurring in Argentina since 1995. We identified (i) a relationship between number of vehicles and a compound socioeconomic indicator, and (ii) time-lags in vehicle technologies between developed and developing countries, which can be respectively applied for spatial disaggregation and the development of projections for other Latin American cities. The results may also be employed to complement global emission inventories and by local policy makers as an environmental management tool.