PM10 and PM2.5 Levels in the Eastern Mediterranean (Akrotiri Research Station, Crete, Greece)

Particulate matter measurements (PM₁₀, PM_2.5) using a beta radiation attenuation monitor were performed at the Akrotiri research station (May 2003–March 2006) on the island of Crete (Greece). The mean PM₁₀ concentration during the measuring period (05/02/03–03/09/04) was equal to 35.0?±?17.7 μg/m³ whereas the mean PM_2.5 concentration (03/10/04–04/02/06) was equal to 25.4?±?16.5 μg/m³. The aerosol concentration at the Akrotiri station shows a large variability during the year. Mean concentrations of particulate matter undergo a seasonal change characterised by higher concentrations during summer [PM₁₀, 38.7?±?10.8 μg/m³ (2003); PM_2.5, 27.9?±?8.7 μg/m³ (2004) and 27.8?±?9.7 μg/m³ (2005)] and lower concentrations during winter [PM₁₀, 28.7?±?22.5 μg/m³ (2003/2004); PM_2.5, 21.0?±?13.0 μg/m³ (2004/2005) and 21.4?±?21.9 μg/m³ (2005/2006)]. Comparative measurements of the PM₁₀ concentration between the beta radiation attenuation monitor, a standardized low volume gravimetric reference sampler and a low volume sequential particulate sampler showed that PM₁₀ concentrations measured by the beta radiation attenuation monitor were higher than values given by the gravimetric samplers (mean ratio 1.17?±?0.11 and 1.21?±?0.08, respectively). Statistical and back trajectory analysis showed that elevated PM concentrations (PM₁₀, 93.8?±?49.1 μg/m³; PM_2.5: 102.9?±?59.9 μg/m³) are associated to desert dust events. In addition regional transport contributes significantly to the aerosol concentration levels whereas low aerosol concentrations were observed during storm episodes.     

Properties and bioavailability of particulate and mineral‐associated organic matter in Arctic permafrost soils,Lower Kolyma Region,Russia

Permafrost degradation may cause strong feedbacks of arctic ecosystems to global warming, but this will depend on if, and to what extent, organic matter (OM) is protected against biodegradation by mechanisms other than freezing and anoxia. Here, we report on the amount, chemical composition and bioavailability of particulate (POM) and mineral‐associated OM (MOM) in permafrost soils of the East Siberian Arctic. The average total organic carbon (OC) stock across all soils was 24.0 ± 6.7 kg m^?2 within 100 cm soil depth. Density fractionation (density cut‐off 1.6 g cm^?3) revealed that 54 ± 16% of the total soil OC and 64 ± 18% of OC in subsoil horizons was bound to minerals. As well as sorption of OM to clay‐sized minerals (R² = 0.80; P < 0.01), co‐precipitation of OM with hydrolyzable metals may also transfer carbon into the mineral‐bound fraction. Carbon:nitrogen ratios, stable carbon and nitrogen isotopes, ¹³C‐NMR and X‐ray photoelectron spectroscopy showed that OM is transformed in permafrost soils, which is a prerequisite for the formation of mineral‐organic associations. Mineral‐associated OM in deeper soil was enriched in ¹³C and ¹⁵N, and had narrow C:N and large alkyl C:(O‐/N‐alkyl C) ratios, indicating an advanced stage of decomposition. Despite being up to several thousands of years old, when incubated under favourable conditions (60% water‐holding capacity, 15°C, adequate nutrients, 90 days), only 1.5–5% of the mineral‐associated OC was released as CO₂. In the topsoils, POM had the largest mineralization but was even less bioavailable than the MOM in subsoil horizons. Our results suggest that the formation of mineral‐organic associations acts as an important additional factor in the stabilization of OM in permafrost soils. Although the majority of MOM was not prone to decomposition under favourable conditions, mineral‐organic associations host a readily accessible carbon fraction, which may actively participate in ecosystem carbon exchange.     

Partitioning of Hg Between Solid and Dissolved Organic Matter in the Humus Layer of Boreal Forests

The mobility of mercury (Hg) deposited on soils controls the concentration and toxicity of Hg within soils and in nearby streams and lakes, but has rarely been quantified under field conditions. We studied the in situ partitioning of Hg in the organic top layer (mor) of podsols at two boreal forest sites differing in Hg deposition and climatic regime (S. and N. Sweden, with pollution declining to the north). Soil solution leaching from the mor layer was repeatedly sampled using zero-tension lysimeters over 2 years, partly in parallel with tension lysimeters. Concentrations of Hg and dissolved organic carbon (DOC) were higher while pH was lower at the southern site (means ± SD: Hg?=?44?±?15 ng L^?1, DOC?=?63.0?±?31.3 mg L^?1, pH?=?4.05?±?0.53) than at the northern site (Hg?=?22?±?6 ng L^?1, DOC?=?41.8?±?12.1 mg L^?1, pH?=?4.28?±?0.43). There was a positive correlation over time between dissolved Hg and DOC at both sites, even though the DOC concentration peaked during autumn at both sites, while the Hg concentration remained more constant. This correlation is consistent with the expected strong association of Hg with organic matter and supports the use of Hg/C ratios in assessments of Hg mobility. In the solid phase of the overlying O_f layer, both Hg concentrations and Hg/C ratios were higher at the southern site (means ± SD: 0.34?±?0.06 μg g^?1 dw and 0.76?±?0.14 μg g^?1 C, respectively) than at the northern site (0.31?±?0.05 μg g^?1 dw and 0.70?±?0.12 μg g^?1 C, respectively). However, concentrations in the solid phase differed less than might be expected from the difference in current atmospheric input, suggesting that the fraction of natural Hg is still substantial. At both sites, Hg/C ratios in the upper half of the mor layer were only about two thirds of those in the lower half, suggesting that the recent decrease in anthropogenic Hg deposition onto the soil is offset by a natural downward enrichment of Hg due to soil decomposition or other processes. Most interestingly, comparison with soil leachate showed that the average Hg/C ratios in the dissolved phase of the mor layers at both sites did not differ from the average Hg/C ratios in the overlying solid organic matter. These results indicate a simple mobilisation with negligible fractionation, despite differences in Hg deposition patterns, soil chemistry and climatic regimes. Such a straight-forward linkage between Hg and organic matter greatly facilitates the parameterisation of watershed models for assessing the biogeochemical fate, toxic effect and critical level of atmospheric Hg input to forest soils.     

The impact of different forest types on phytolith-occluded carbon accumulation in subtropical forest soils

Purpose

Occlusion of carbon in phytoliths is an important biogeochemical carbon sequestration mechanism and plays a significant role in the global biogeochemical carbon cycle and atmospheric carbon dioxide (CO₂) concentration regulation at a millennial scale. However, few studies have focused on the storage of phytolith and phytolith-occluded carbon (PhytOC) in subtropical forest soils.

Materials and methods

Soil profiles with 100-cm depth were sampled from subtropical bamboo forest, fir forest, and chestnut forest in China to investigate the variation of phytoliths and PhytOC storage in the soil profiles based on amass-balance assessment.

Results and discussion

The storage of phytoliths in the top 100 cm of the bamboo forest soil (198.13?±?25.08 t ha^?1) was much higher than that in the fir forest (146.76?±?4.53 t ha^?1) and chestnut forest (170.87?±?9.59 t ha^?1). Similarly, the storage of PhytOC in the bamboo forest soil (3.91?±?0.64 t ha^?1) was much higher than that in the fir forest soil (1.18?±?0.22 t ha^?1) and chestnut forest soil (2.67?±?0.23 t ha^?1). The PhytOC percentage in the soil organic carbon pool increased with soil depth and was the highest (4.29 %) in the bamboo forest soil. Our study demonstrated that PhytOC in soil was significantly influenced by forest type and the bamboo forest ecosystem contributed more significantly to phytolith carbon sequestration than other forest ecosystems.

Conclusions

Different forest types have a significant influence on the soil PhytOC storage. Optimization of bamboo afforestation/reforestation in future forest management plans may significantly enhance the biogeochemical carbon sink in the following centuries.

     

Performances of Methyl Blue and Arsenic(V) Adsorption from Aqueous Solution onto Magnetic 0.8Ni0.5Zn0.5Fe2O4/0.2SiO2 Nanocomposites

Washing-down parlours and standing areas, following milking on dairy farms, produce dairy soiled water (DSW) that contains variable concentrations of nutrients. Aerobic woodchip filters can remove organic matter, nutrients and suspended solids (SS) in DSW, but the effluent exiting the filters may have to be further treated before it is suitable for re-use for washing yard areas. The performance of a single-layer sand filter (SF) and a stratified SF, loaded at 20 L m^?2 day^?1, to polish effluent from a woodchip filter was investigated over 82 days. Average influent unfiltered chemical oxygen demand (COD_T), total nitrogen (TN), ammonium–N (NH₄–N), ortho-phosphorus (PO₄–P) and SS concentrations of 1,991?±?296, 163?±?40, 42.3?±?16.9, 27.2?±?6.9 and 84?±?30 mg L^?1 were recorded. The single-layer SF decreased the influent concentration of COD_T, TN, NH₄–N, PO₄–P and SS by 39, 36, 34, 58 and 52 %, respectively. Influent concentrations of COD_T, TN_T, NH₄–N, PO₄–P and SS were decreased by 56, 57, 41, 74 and 62 % in the stratified SF. The single-layer SF and the stratified SF were capable of reducing the influent concentration of total coliforms by 96 and 95 %, respectively. Although a limited amount of biomass accumulated in the uppermost layers of both SFs, organic and particulate matter deposition within both filters affected rates of nitrification. Both types of SFs produced final water quality in excess of the standards for re-use in the washing of milking parlours.     

Fly ash concentrations in philadelphia aerosol determined by electron microscopy

In a study to differentiate between coal-fly ash and minerals in the atmosphere, samples were collected on Nuclepore filters in dichotomous samplers and analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry. The samples included ambient aerosol from two sites, resuspended soil, and emissions from coal- and oil-fired power plants in the Philadelphia area. Fly ash and minerals were identified by observing high abundances of Al, Si, K, Ca, Ti, and Fe in individual particles, and their mass concentrations were estimated from measured dimensions and an assumed density. Fly ash was distinguished from minerals by morphology. Sulfate was the major component of the fine fraction (<2.5 μm aerodynamic dia.). Crustal matter concentrations in the fine fraction estimated by SEM ranged from 40 to 300 ng m^?3, and fly ash accounted for 7 to 62% of the crustal matter. In the coarse fraction (2.5 to 10 μm), minerals were the predominant component and ranged in concentration from 500 to 6000 ng m^?3. Fly ash accounted for 0 to 16% of the crustal matter; the typical amount was 6%. Other less abundant coarse particles included botanical matter and industrial source emissions. Coarse fraction crustal matter estimated from x-ray fluorescence elemental data agreed well with that based on electron microscopy.     

Soil Quality Assessment under Restorative Soil Management Practices in Soybean (Glycine Max) after Six Years in Semi-Arid Tropical Black Lands of Central India

Vertisol soils of central India are heavy in texture, with high clay content and low organic matter. These soils are prone to degradation and the soil loss is due to poor management practices including excessive tillage. Based on a long-term study conducted for improving the quality of these soils, it was found that management practice such as low tillage (LT) + 4 t ha^?1 compost + herbicide (Hb) recorded significantly higher organic carbon (OC) (6.22 g kg^?1) and available N (188.5 kg ha^?1) compared to conventional tillage (CT) + recommended fertilizer (RF) + off-season tillage (OT) + hand weeding (HW) (OC: 4.71 g kg^?1, available nitrogen (N) (159.3 kg ha^?1). Among the physical soil quality parameters, mean weight diameter (MWD) was significantly higher under LT + 4 t ha^?1 straw + Hb (0.59 mm). The practice of LT + 4 t ha^?1 straw + HW recorded significantly higher microbial biomass carbon (MBC) (388.8 μg g^?1). The order of key indicators and their contribution towards soil quality was as follows: OC (29%) >, MBC (27%) > available zinc (Zn) (22%) > MWD (9%) > available boron (B) (8%), > dehydrogenase activity (DHA) (5%). The order of the best treatment which maintained soil quality index (SQI) values reasonably good (>1.5) was as follows: LT + 4t ha^?1 compost + HW (1.65) > LT + 4 t ha^?1 compost +Hb (1.60) > LT + 4t ha^?1 straw + HW (1.50). Hence, these treatments could be recommended to the farmers for maintaining higher soil quality in Vertisols under soybean system. Correlation studies revealed stronger relationship between key indicators like OC (R² = 0.627), MBC (R² = 0.884), available Zn (R² = 0.739) and DHA (R² = 0.604) with Relative Soil Quality Index (RSQI). The results of the present study would be highly useful to the researchers, farmers and land managers.     

Effect of elevated carbon dioxide on growth and nitrogen fixation of two soybean cultivars in northern China

The effect of elevated carbon dioxide (CO₂) concentration on symbiotic nitrogen fixation in soybean under open-air conditions has not been reported. Two soybean cultivars (Glycine max (L.) Merr. cv. Zhonghuang 13 and cv. Zhonghuang 35) were grown to maturity under ambient (415?±?16?μmol?mol^?1) and elevated (550?±?17?μmol?mol^?1) [CO₂] at the free-air carbon dioxide enrichment experimental facility in northern China. Elevated [CO₂] increased above- and below-ground biomass by 16–18% and 11–20%, respectively, but had no significant effect on the tissue C/N ratio at maturity. Elevated [CO₂] increased the percentage of N derived from the atmosphere (%Ndfa, estimated by natural abundance) from 59% to 79% for Zhonghuang 13, and the amount of N fixed from 166 to 275?kg N ha^?1, but had no significant effect on either parameter for Zhonghuang 35. These results suggest that variation in N₂ fixation ability in response to elevated [CO₂] should be used as key trait for selecting cultivars for future climate with respect to meeting the higher N demand driven by a carbon-rich atmosphere.     

Nutrient storage in termite (Macrotermes bellicosus) mounds and the implications for nutrient dynamics in a tropical savanna Ultisol

The role of mounds of the fungus-growing termite Macrotermes bellicosus (Smeathman) in nutrient recycling in a highly weathered and nutrient-depleted tropical red earth (Ultisol) of the Nigerian savanna was examined by measuring stored amounts of selected nutrients and estimating their rates of turnover via the mounds. A study plot (4?ha) with a representative termite population density (1.5?mounds?ha^?1) and size (3.7?±?0.4?m in height, 2.4?±?0.2?m in basal diameter) of M. bellicosus mounds was selected. The mounds were found to contain soil mass of 9249?±?2371?kg?ha^?1, composed of 7502?±?1934?kg?ha^?1 of mound wall and 1747?±?440?kg?ha^?1 of nest body. Significant nutrient enrichment, compared to the neighboring topmost soil (Ap1 horizon: 0–16?cm), was observed in the nest body for total nitrogen (N) and exchangeable calcium (Ca), magnesium (Mg) and potassium (K), and in the mound wall for exchangeable K only. In contrast, available (Bray-1) phosphorus (P) content was found to be lower in both the mound wall and the nest body than in the adjacent topmost soil horizon. Consequently, the mounds formed by M. bellicosus contained 1.71?±?0.62?kg?ha^?1 of total N, 0.004?±?0.003?kg?ha^?1 of available P, 3.23?±?0.81?kg?ha^?1 of exchangeable Ca, 1.11?±?0.22?kg?ha^?1 of exchangeable Mg and 0.79?±?0.21?kg?ha^?1 of exchangeable K. However, with the exception of exchangeable K (1.2%), these nutrients amounted to less than 0.5% of those found in the topmost soil horizon. The soil nutrient turnover rate via M. bellicosus mounds was indeed limited, being estimated at 1.72?kg?ha^?1 for organic carbon (C), 0.15?kg?ha^?1 for total N, 0.0004?kg?ha^?1 for available P, 0.15?kg?ha^?1 for exchangeable Ca, 0.05?kg?ha^?1 for exchangeable Mg, and 0.06?kg?ha^?1 for exchangeable K per annum. These findings suggest that the mounds of M. bellicosus, while being enriched with some nutrients to create hot spots of soil nutrients in the vicinity of the mounds, are not a significant reservoir of soil nutrients and are therefore of minor importance for nutrient cycling at the ecosystem scale in the tropical savanna.     

Aerosol and cloudwater properties at whiteface mountain,New York

A field program for the measurement of the physical and chemical properties of aerosols and clouds was conducted at Whiteface Mountain, N.Y., during an 8-week period in June, July, and August 1983. Analysis of two-stage Nuclepore filter samples by proton-induced X-ray emission (PIXE) spectroscopy showed that most (85 to 90%) of the aerosol sulfate was in the accumulation mode (modal radius r - 0.1 μm) and that ?90% of total sulfate originated southwest of the Whiteface Mountain site. During a typical pollution episode originating in the Midwest, the total aerosol sulfate concentration was 19 pg m ^?3, or 63 of total dry aerosol, which was - 30 gg m^? s. Scavenging of sulfate aerosol by clouds was found to be greater than 95% efficient in clouds of 0.5gm^?3 liquid water content. Measured pH values when the air mass trajectories were from the southwest were systematically lower than when the trajectories were from the northwest or northeast, i.e., 3.4 vs 4.4 and 4.8. In the southwest sector water samples, S0₄ ^?2 and N0₃ ^? were highly correlated to each other and to free H⁺, Ca₂ ^?, Cl^?, Pb, and Ba.     

Sediment denitrification in waterways in a rice-paddy-dominated watershed in eastern China

Purpose

Rice-paddy-dominated watersheds in eastern China are intensively cultivated, and lands with two crops receive as much as 550–600 kg?ha^–1?year^–1 of nitrogen (N), mainly through the addition of N-based fertilizers. However, stream N concentrations have been found to be relatively low. Waterways in the watersheds are assumed to be effective “sinks” for N, minimizing its downstream movement. We directly measured net sediment denitrification rates in three types of waterways (ponds, streams/rivers, and a reservoir) and determined the key factors that control net sediment denitrification. Such information is essential for evaluating the impact of the agricultural N cycle on the quality of surface water.

Materials and methods

The pond–stream–reservoir continuum was sampled every 2 months at nine sites in an agricultural watershed between November 2010 and December 2011. Net sediment N₂ fluxes/net sediment denitrification rates were determined by membrane inlet mass spectrometry and the N₂/Ar technique. A suite of parameters known to influence denitrification were also measured.

Results and discussion

Net denitrification rates ranged between 28.2?±?18.2 and 674.3?±?314.5 μmol N₂–N?m^–2?h^–1 for the streams, 23.7?±?23.9 and 121.2?±?38.7 μmol N₂–N?m^–2?h^–1 for the ponds, and 41.8?±?17.7 and 239.3?±?49.8 μmol N₂–N?m^–2?h^–1 for the reservoir. The mean net denitrification rate of the stream sites (173.2?±?248.4 μmol N₂–N?m^–2?h^–1) was significantly higher (p?<?0.001) than that of the pond sites (48.3?±?44.5 μmol N₂–N?m^–2?h^–1), and the three types of waterways all had significantly higher (p?<?0.01) mean net denitrification rates in summer than in other seasons. Linear regression and linear mixed effect model analysis showed that nitrate (NO₃ ^?–N) concentration in surface water was the primary controlling factor for net sediment denitrification, followed by water temperature. Using monitoring data on NO₃ ^?–N concentrations and temperature of the surface water of waterways and an established linear mixed effect model, total N removed through net sediment denitrification in the pond–stream–reservoir continuum was estimated at 46.8?±?24.0 t?year^–1 from July 2007 to June 2009, which was comparable with earlier estimates based on the mass balance method (34.3?±?12.7 t?year^–1), and accounted for 83.4 % of the total aquatic N. However, the total aquatic N was only 4.4 % of the total N input to the watershed, and thus most of the surplus N in the watershed was likely to be either denitrified or stored in soil.

Conclusions

High doses of N in a rice-paddy-dominated watershed did not lead to high stream N concentrations due to limited input of N into waterways and the high efficiency of waterways in removing N through denitrification.     

Soil organic carbon in density fractions of tropical soils under forest – pasture – secondary forest land use changes

Our knowledge of effects of land use changes and soil types on the storage and stability of different soil organic carbon (SOC) fractions in the tropics is limited. We analysed the effect of land use (natural forest, pasture, secondary forest) on SOC storage (depth 0–0.1 m) in density fractions of soils developed on marine Tertiary sediments and on volcanic ashes in the humid tropics of northwest Ecuador. The origin of organic carbon stored in free light (< 1.6 g cm^?3) fractions, and in two light fractions (LF) occluded within aggregates of different stability, was determined by means of δ¹³C natural abundance. Light occluded organic matter was isolated in a first step after aggregate disruption by shaking aggregates with glass pearls (occluded I LF) and in a subsequent step by manual destruction of the most stable microaggregates that survived the first step (occluded II LF). SOC storage in LFs was greater in volcanic ash soils (7.6 ± 0.6 Mg C ha^?1) than in sedimentary soils (4.3 ± 0.3 Mg C ha^?1). The contribution of the LFs to SOC storage was greater in natural forest (19.2 ± 1.2%) and secondary forest (16.6 ± 1.0%) than in pasture soils (12.8 ± 1.0%), independent of soil parent material. The amount of SOC stored in the occluded I LF material increased with increasing silt + clay content (sedimentary soils, r = 0.73; volcanic ash soils, r = 0.58) and aggregation (sedimentary soils, r = 0.52; volcanic ash soils, r = 0.45). SOC associated with occluded I LF, had the smallest proportion of new, pasture‐derived carbon, indicating the stabilizing effect of aggregation. Fast turnover of the occluded II LF material, which was separated from highly stable microaggregates, strongly suggested that this fraction is important in the initial process of aggregate formation. No pasture‐derived carbon could be detected in any density fractions of volcanic ash soils under secondary forest, indicating fast turnover of these fractions in tropical volcanic ash soils.     

Atmospheric Total Suspended Particulate Trace Element Identification by XRF at Ilha Grande, State of Rio De Janeiro, Brazil

Phosphorus, manganese, sulfur (S), lead, and strontium of atmospheric total suspended particulate matter, sampled during the rainy season and the dry season 2002 at the Ilha Grande Island (Rio de Janeiro State, Brazil) have been analyzed by XRF techniques. The results showed total mean concentrations of 27?±?16 ng P m^-3, 11?±?7 ng Mn m^-3, 159?±?126 ng S m^-3, 4.3?±?2.6 ng Pb m^-3, and 208?±?148 ng Sr m^-3. Generally, there is no clear influence of the two different climatic periods on the concentrations of most analyzed trace elements, with exception of sulfur the mean concentration of which, during the dry season, is about 60% higher than during the rainy season. This is probably due to biomass burning, a common practice in the Brazilian Southeast and Amazon region and/or to the presence of marine aerosols. The linear correlation coefficients strongly suggest the same source for P, Pb, and Mn. Some Pb, Mn, and P concentrations are in the range of typical values of urban areas. Potential sources of such elements are the urban and industrial emissions from the States of Rio de Janeiro and/or São Paulo.     

Transfer of 137Cs and 40K from Agricultural Soils to Food Products in Terrestrial Environment of Tarapur, India

The ¹³⁷Cs and ⁴⁰K activities and transfer factors from soil to vegetables, grass, and milk from villages located around Tarapur Atomic Power Station (TAPS) were determined using high-resolution gamma spectrometry. A total of 32 soil, 21 vegetable, 23 dry paddy grass, and 23 milk samples were collected from 23 different agricultural farms from various villages around TAPS to determine transfer factors for natural environment. The mean concentration values for ¹³⁷Cs and ⁴⁰K in soil, grass, and milk were 2.39?±?0.86 Bq kg^?1, 0.31?±?0.23 Bq kg^?1, and 12.4?±?5.7 mBq L^?1 and 179?±?31 Bq kg^?1, 412?±?138 Bq kg^?1, and 37.6?±?9.3 Bq L^?1, respectively, for soil?Cgrass?Cmilk pathway. In the soil?Cvegetation pathway, the mean concentrations values for ¹³⁷Cs and ⁴⁰K were 2.15?±?1.04 Bq kg^?1, 16.5?±?7.5 mBq kg^?1, and 185?±?24, 89?±?50 Bq kg^?1, respectively. The evaluated mean transfer factors from soil?Cgrass, grass?Cmilk, and soil?Cvegetation for ¹³⁷Cs were 0.14, 0.0044, and 0.0073 and that of ⁴⁰K were 2.42, 0.0053, and 0.49, respectively. Only 15 out of total 44 milk and vegetable samples were detected positive for ¹³⁷Cs, indicating a very low level of bioavailability.     

Wet and Dry Deposition Fluxes of Polychlorinated Biphenyls (PCBs) in an Urban Area of Turkey

Atmospheric polychlorinated bihenyls (PCBs) deposit by dry and wet deposition mechanisms, and therefore they constitute a significant polluting source for lands and surface waters. Various samplers have been used to determine the PCB pollution level resulting from deposition. In the presented study, a modified wet deposition sampler (WDS) was used for sampling both wet and dry deposition samples with the same instrument by which wet deposition reservoir of the WDS is opened and dry deposition reservoir is closed when rain starts. Wet and dry deposition samples were collected between June 2008 and June 2009. In the samples taken from BUTAL which is known as an urban area with heavy traffic, ??PCB dry deposition fluxes were determined as 18?±?10 ng/m²??day, and wet deposition fluxes for dissolved and particle phase were measured as 480?±?1,185 and 475?±?1,000 ng/m²??day, respectively. The dissolved and particle-phase PCB concentrations in rain were 10?±?13 and 13?±?14 ng/l, respectively. The contribution of wet deposition to total PCB deposition was determined as 52%. PCB concentrations in the ambient air were measured to be 370?±?200 and 20?±?20 pg/m³ for gas and particle phases, respectively. Washout ratio was determined by proportioning rain concentration to concentration in air. The washout ratios of the samples were between 1,675?C311,800 and 12,775?C2,511,120 for dissolved and particulate phases, respectively.     

Annual monitoring of rainwater sulphate in an urban zone of Rome (Italy)

The sulphate ion concentrations in rainwater samples, collected in a central area of Rome (Italy), were measured by an indirect atomic absorption spectrometric method. The reproducibility of sample preparations and analysis were found to have a max SD: ± 20%. The month to month variation in SO _f4 ^p2? concentration varied from 3 to 27 μg mL^?1.     

Ammonia,Nitrous Oxide,Carbon Dioxide and Methane Emissions from Commercial Broiler Houses in Mediterranean Portugal

Limited data are available on ammonia (NH₃), nitrous oxide (N₂O), carbon dioxide (CO₂) and methane (CH₄) emissions from poultry housing in Mediterranean countries. The aim of the present study was to assess the NH₃, N₂O, CO₂ and CH₄ emission rates from commercial breeding hen and broiler houses under Mediterranean climate conditions. Research was conducted at one commercial breeding hen house and in two commercial broiler houses located in central Portugal. The environmental conditions, gas concentrations and ventilation rates were measured in the cold (8.0?±?2.1 °C) and hot (20.7?±?1.9 °C) season for the breeding hen house, whereas for the two broiler houses, measurements were made during one fattening cycle in the fall (17.3?±?1.7 °C) season. Results showed that the annual average emission rates for breeding hen and broiler houses were 0.52?±?0.27 and 0.06?±?0.01 for NH₃, 0.030?±?0.042 and 0.006?±?0.001 for N₂O, 169.6?±?56.2 and 58.0?±?15.1 for CO₂ and 0.092?±?0.131 and 0.0113?±?0.0002 g day^?1 bird^?1 for CH₄, respectively. The N₂O emission rates observed in breeding hen houses may have been overestimated, being higher than previously reported for Mediterranean countries.     

Toxicity of Lead to Freshwater Invertebrates (Water fleas; Daphnia magna and Cyclop sp) in Fish Ponds in a Tropical Floodplain

Acute toxicity of Pb to the water flea; (Daphnia sp) and Copepod, (Cyclop sp) both important component of zooplankton diet of fish was determined by static assay. A positive relationship between percentage mortality and exposure concentration was found in all tests. Mean 24-h LC50, 48-h LC50 and 96-h LC50 values were 2.51?±?0.0.04 mg l^?1, 1.88?±?0.06 mg l^?1 and 1.65?±?0.19 mg l^?1 for Daphnia spp and 3.11?±?0.03 mg l^?1, 2.97?±?0.05 mg l^?1 and 2.61?±?0.09 mg l^?1 for Cyclop spp, respectively. For all tested species did the LC50 values decrease with time; the decrease was more marked for Daphnia spp. Observed symptoms include spiral movement followed by change of body colour to white and rapid disintegration of the skin. The Daphnia spp. appear to be more sensitive to Pb poison than Cyclop spp. The results showed that concentrations of Lead (Pb) in excess of 0.19 mg l^?1 and 0.30 mg l^?1 can be potentially harmful to Daphnia magna and Cyclop spp respectively.     

Impact of ski pistes on soil properties: a case study from a mountainous area in the Mediterranean region

In this study, soils on 17 ski pistes in the Sierra Nevada, Spain, were investigated to identify changes induced by ski management practices and also to determine the effectiveness of grass seeding in restoring soil quality. When compared with unaffected reference soils, those of ski runs had substantial loss of organic carbon (?34%, ?11.9 ± 3.6 t ha^?1) and micropore volume and size (?33%, ?0.07 ± 0.01 cm³ cm^?3 and ?48%, ?1.62 ± 0.28 μm). Microstructure showed a dramatic reduction in organic cements and fungal hyphae. The organic content of soil seeded with grass significantly improved compared with soil not seeded or seeded unsuccessfully (P < 0.05), especially where the topsoil was reinstated. Organic C content, microporosity and soil respiration increased by 200% (+21 ± 5 t ha^?1), 70% (+0.07 ± 0.03 cm³ cm^?3) and 140% (+0.10 ± 0.04 mg CO₂ g^?1 day^?1), respectively. Average micropore size in aggregates which in undisturbed soils was 3.40 ± 0.28 μm reverted to 3.52 ± 0.36 μm. However, the microstructure of the revegetated soils did not attain the levels of organic cements and fungal hyphae in the natural soils. Dolomite and salts were added to the soil to aid slope stabilization, fertility and de‐icing of access tracks. As a consequence, there were increases in pH, exchangeable sodium percentage (ESP), electrical conductivity, calcium carbonate equivalent and base saturation. The influence of management on soil properties was found to be greater than that of environmental factors.     

Manure amendment reduced plant uptake and enhanced rhizodegradation of 2,2′,4, 4′-tetrabrominated diphenyl ether in soil

To test whether manure amendment in soil reduces plant uptake of persistent organic pollutants, carrot (Daucus carota L.) was used as a model plant and 2,2′,4,4′-tetrabrominated diphenyl ether (BDE-47) was selected as a model persistent organic pollutant to conduct a pot experiment with contaminated soil amended by composted pig manure. The results showed that the concentration and bioconcentration factors (BCFs) of BDE-47 in the edible part of carrot significantly decreased from 229.7?±?28.2 to 43.4?±?20.4 ng g^?1 and from 1.86?±?0.5 to 0.15?±?0.03, respectively, with increasing composted pig manure dose from 0 to 4%. Organic matter (OM) derived from composted pig manure played a dominant role in reducing persistent organic pollutant bioavailability in soil. Composted pig manure amendment and carrot cultivation jointly altered the bacterial community composition in soil, especially the rhizosphere. Rhizodegradation of BDE-47 was enhanced from 8.6 to 28.5% with increasing composted pig manure dose from 0 to 4%, corresponding to increased soil microbe diversity and polybrominated diphenyl ether-degrading bacteria (Sphingomonas, etc.) abundance in the rhizosphere. This study is the first, to the best of our knowledge, to provide an effective agronomic strategy of manure amendment to reduce plant uptake and simultaneously enhance rhizodegradation of persistent organic pollutants in soil, and thus potentially reduce human health risks through dietary intake.