Atmospheric NH3 and NO2 concentration and nitrogen deposition in an agricultural catchment of Eastern China

To assess the atmospheric environmental impacts of anthropogenic reactive nitrogen in the fast-developing Eastern China region, we measured atmospheric concentrations of nitrogen dioxide (NO₂) and ammonia (NH₃) as well as the wet deposition of inorganic nitrogen (NO₃⁻ and NH₄⁺) and dissolved organic nitrogen (DON) levels in a typical agricultural catchment in Jiangsu Province, China, from October 2007 to September 2008_. The annual average gaseous concentrations of NO₂ and NH₃ were 42.2 μg m⁻³ and 4.5 μg m⁻³ (0 °C, 760 mm Hg), respectively, whereas those of NO₃⁻, NH₄⁺, and DON in the rainwater within the study catchment were 1.3, 1.3, and 0.5 mg N L⁻¹, respectively. No clear difference in gaseous NO₂ concentrations and nitrogen concentrations in collected rainwater was found between the crop field and residential sites, but the average NH₃ concentration of 5.4 μg m⁻³ in residential sites was significantly higher than that in field sites (4.1 μg m⁻³). Total depositions were 40 kg N ha⁻¹ yr⁻¹ for crop field sites and 30 kg N ha⁻¹ yr⁻¹ for residential sites, in which dry depositions (NO₂ and NH₃) were 7.6 kg N ha⁻¹ yr⁻¹ for crop field sites and 1.9 kg N ha⁻¹ yr⁻¹ for residential sites. The DON in the rainwater accounted for 16% of the total wet nitrogen deposition. Oxidized N (NO₃⁻ in the precipitation and gaseous NO₂) was the dominant form of nitrogen deposition in the studied region, indicating that reactive forms of nitrogen created from urban areas contribute greatly to N deposition in the rural area evaluated in this study.     

Estimates of Asian dust deposition over the Asian region by using ADAM2 in 2007

The Asian Dust Aerosol Model 2 (ADAM2) with the MM5 meteorological model has been employed to estimate the dust concentration, and wet and dry depositions of dust in the Asian region for the year of 2007. It is found that the model simulates quite reasonably the dust (PM₁₀) concentrations both in the dust source region (100-110°E and 37-43°N) and the downstream region of Korea. The starting and ending times of most of dust events and their peak concentration occurring times are well simulated. The annual average dust (PM₁₀) concentration near the surface is found to be 171 μg m^− 3 over the dust source area, 39 μg m^− 3 over the Yellow Sea, 25 μg m^− 3 over the Korean peninsula and 17 μg m^− 3 over the East Sea. It is also found that the annual total deposition of dust is about 118.1 t km^− 2 (dry deposition, 101.4 t km^− 2; wet deposition, 16.7 t km^− 2) in the dust source region, 19.0 t km^− 2 (dry deposition, 7.8 t km^− 2; wet deposition, 11.2 t km^− 2) in the Yellow Sea, 12.6 t km^− 2 (dry deposition, 6.5 t km^− 2; wet deposition, 6.1 t km^− 2) in the Korean peninsula and 10.7 t km^− 2 (dry deposition, 2.1 t km^− 2; wet deposition, 8.6 t km^− 2) in the East Sea. Their ratios of wet deposition to total deposition of dust in the respective regions are 14%, 59%, 48% and 80%. This clearly indicates that the main dust removal mechanism from the atmosphere is dry deposition over the source region whereas wet deposition predominates in the downstream region of the sea. The estimated dust deposition could adversely impact the eco-environmental system in the downstream regions of the dust source region significantly.     

Pollution of montane soil with Cu, Zn, As, Sb, Pb, and nitrate in Kanto, Japan

Soil cores and rainwater were sampled under canopies of Cryptomeria japonica in four montane areas along an atmospheric depositional gradient in Kanto, Japan. Soil cores (30 cm in depth) were divided into 2-cm or 4-cm segments for analysis. Vertical distributions of elemental enrichment ratios in soils were calculated as follows: (X/Al)_i/(X/Al)_BG (where the numerator and denominator are concentration ratios of element-X and Al in the i- and bottom segments of soil cores, respectively). The upper 14-cm soil layer showed higher levels of Cu, Zn, As, Sb, and Pb than the lower (14-30 cm) soil layer. In the four areas, the average enrichment ratios in the upper 6-cm soil layer were as follows: Pb (4.93) ≥ Sb (4.06) ≥ As (3.04) > Zn (1.71) ≥ Cu (1.56). Exogenous elements (kg/ha) accumulated in the upper 14-cm soil layer were as follows: Zn (26.0) > Pb (12.4) > Cu (4.48) ≥ As (3.43) ≥ Sb (0.49). These rank orders were consistent with those of elements in anthropogenic aerosols and polluted (roadside) air, respectively, indicating that air pollutants probably caused enrichment of these elements in the soil surface layer. Approximately half of the total concentrations of As, Sb, and Pb in the upper 14-cm soil layer were derived from exogenous (anthropogenic) sources. Sb showed the highest enrichment factor in anthropogenic aerosols, and shows similar deposition behavior to NO₃⁻, which is a typical acidic air pollutant. There was a strong correlation between Sb and NO₃⁻ concentrations in rainfall (e.g., in the throughfall under C. japonica: [NO₃⁻] = 21.1 [dissolved Sb], r = 0.938, p < 0.0001, n = 182). Using this correlation, total (cumulative) inputs of NO₃⁻ were estimated from the accumulated amounts of exogenous Sb in soils, i.e., 16.7 t/ha at Mt. Kinsyo (most polluted), 8.6 t/ha at Mt. Tsukuba (moderately polluted), and 5.8 t/ha at the Taga mountain system (least polluted). There are no visible ecological effects of these accumulated elements in the Kanto region at present. However, the concentrations of some elements are within a harmful range, according to the Ecological Soil Screening Levels determined by the U.S. Environmental Protection Agency.     

Urea: An important piece of Water Soluble Organic Nitrogen (WSON) over the Eastern Mediterranean

The role of atmospheric urea on the biogeochemical cycle of Water Soluble Organic Nitrogen (WSON) in the Eastern Mediterranean was assessed by collecting and analyzing wet and dry deposition samples and size segregated aerosols during a one year period (2006). In rain water volume weighted mean (VWM) concentration of urea was found equal to 5.5 μM. In atmospheric particles the average concentration of urea in coarse and fine mode was 0.9 ± 1.9 nmol N m^− 3 (median 0.0 nmol N m^− 3) and 2.2 ± 3.0 nmol N m^− 3 (median 1.1 nmol N m^− 3), respectively. The percentage contribution of urea to WSON fraction was 0% and 20% in coarse and fine particles respectively. On an annual basis 0.81 mmol m^− 2 and 1.78 mmol m^− 2 of urea were deposited via wet and dry deposition, contributing to WSON by 10% and 11% respectively. Regression analysis of urea with the main ions and trace metals measured in parallel suggest that soil and anthropogenic activities significantly contribute to atmospheric urea. Comparison of dry deposition of urea using size segregated deposition velocities with urea collected on a glass bead collector suggested the existence of significant fraction of urea in the gas phase.     

Toxic metals in the atmosphere in Lahore, Pakistan

Aerosol mass (PM₁₀ and PM_2.5) and detailed elemental composition were measured in monthly composites during the calendar year of 2007 at a site in Lahore, Pakistan. Elemental analysis revealed extremely high concentrations of Pb (4.4 μg m^− 3), Zn (12 μg m^− 3), Cd (0.077 μg m^− 3), and several other toxic metals. A significant fraction of the concentration of Pb (84%), Zn (98%), and Cd (90%) was contained in the fine particulate fraction (PM_2.5 and smaller); in addition, Zn and Cd were largely (≥ 60%) water soluble. The 2007 annual average PM₁₀ mass concentration was 340 μg m^− 3, which is well above the WHO guideline of 20 μg m^− 3. Dust sources were found to contribute on average (maximum) 41% (70%) of PM₁₀ mass and 14% (29%) of PM_2.5 mass on a monthly basis. Seasonally, concentrations were found to be lowest during the monsoon season (July-September). Principle component analysis identified seven factors, which combined explained 91% of the variance of the measured components of PM₁₀. These factors included three industrial sources, re-suspended soil, mobile sources, and two regional secondary aerosol sources likely from coal and/or biomass burning. The majority of the Pb was found to be associated with one industrial source, along with a number of other toxic metals including As and Cr. Cadmium, another toxic metal, was found at concentrations 16 times higher than the maximum exposure level recommended by the World Health Organization, and was concentrated in one industrial source that was also associated with Zn. These results highlight the importance of focusing control strategies not only on reducing PM mass concentration, but also on the reduction of toxic components of the PM as well, to most effectively protect human health and the environment.     

Anthropogenic acidification effects in primeval forests in the Transcarpathian Mts., western Ukraine

The precipitation chemistry, deposition, nutrient pools and composition of soils and soil water, as well as an estimate of historical deposition of sulphur (S) and inorganic nitrogen (N) for the period 1860-2008, were determined in primeval deciduous and coniferous forests at the sites Javornik and Pop Ivan, respectively. Measured S throughfall inputs of 10 kg ha^− 1 year^− 1 in 2008 were similar to those estimated for the period 1900-1950 at both sites. The highest estimated S inputs were in the 1980s. Measured bulk deposition of N in 2008 was lower at Pop Ivan (5.6 kg ha^− 1 year^− 1) compared to Javornik (12 kg ha^− 1 year^− 1). Significantly lower NO₃ deposition was both estimated and measured at Pop Ivan. Higher soil base cation concentrations were observed at well-buffered Javornik underlain by flysch (Ca pool of 2046 kg ha^− 1 and base saturation of 29%) compared to Pop Ivan underlain by crystalline schist (Ca pool of 186 kg ha^− 1 and base saturation of 6.5%). The soil pool of organic carbon (C) was higher at Pop Ivan (212 t ha^− 1) compared to Javornik (127 t ha^− 1). The C concentration was positively correlated with organic N in the soil (p < 0.001) at both sites, but the mass average C/N ratio in the forest floor was lower at Javornik (22) than at Pop Ivan (26). High N leaching of 17 kg ha^− 1 year^− 1 at the 90 cm depth was measured in the soil water at Javornik, suggesting high mineralization and nitrification rates in old growth deciduous forests in the area. Despite relatively low Al concentrations in the soil water, a low soil water Bc/Al ratio (0.9) (Bc = Ca + Mg + K) was found in the upper mineral soil at Pop Ivan. This suggests that the spruce forest ecosystems in the area are vulnerable to anthropogenic acidification and to the adverse effects of Al on forest root systems.     

Water, vegetation and sediment gradients in submerged aquatic vegetation mesocosms used for low-level phosphorus removal

Gradients in phosphorus (P) removal and storage were investigated over 6 years using mesocosms (each consisting of three tanks in series) containing submerged aquatic vegetation (SAV) grown on muck and limerock (LR) substrates. Mean inflow total P concentrations (TP) of 32 μg L⁻¹ were reduced to 15 and 17 μg L⁻¹ in the muck and LR mesocosms, respectively. Mesocosm P loading rates (mean = 1.75 g m⁻² year⁻¹) varied widely during the study and were not correlated with outflow TP, which instead varied seasonally with lowest monthly mean values in December and January.The mesocosms initially were stocked with Najas guadalupensis, Ceratophyllum demersum, and Chara zeylanica, but became dominated by C. zeylanica. At the end of the study, highest vegetative biomass (1.1 and 1.4 kg m⁻² for muck and LR substrates) and tissue P content (1775 and 1160 mg kg⁻¹) occurred in the first tank in series, and lowest biomass (1.0 and 0.2 kg m⁻²) and tissue P (147 and 120 mg kg⁻¹) in the third tank. Sediment accretion rates (2.5, 1.9 and 0.9 cm yr⁻¹ on muck substrates), accrued sediment TP (378, 309 and 272 mg kg⁻¹), and porewater soluble reactive P (SRP) concentrations (40, 6 and 4 μg L⁻¹) in the first, second and third tanks, respectively, exhibited a similar decreasing spatial trend. Plant tissue calcium (Ca) near mesocosm inflow (19-30% dry weight) and outflow (23-26%) were not significantly different, and sediment Ca was also similar (range of 24 to 28%) among sequential tanks.Well-defined vegetation and sediment enrichment gradients developed in SAV wetlands operated under low TP conditions. While the mesocosm data did not reflect deterioration in treatment performance over 6 years, accumulation of P-enriched sediments near the inflow could eventually compromise hydraulic storage and P removal effectiveness of these shallow systems.     

Manganese and lead in children's blood and airborne particulate matter in Durban, South Africa

Despite the toxicity and widespread use of manganese (Mn) and lead (Pb) as additives to motor fuels and for other purposes, information regarding human exposure in Africa is very limited. This study investigates the environmental exposures of Mn and Pb in Durban, South Africa, a region that has utilized both metals in gasoline. Airborne metals were sampled as PM_2.5 and PM₁₀ at three sites, and blood samples were obtained from a population-based sample of 408 school children attending seven schools. In PM_2.5, Mn and Pb concentrations averaged 17 ± 27 ng m^− 3 and 77 ± 91 ng m^− 3, respectively; Mn concentrations in PM₁₀ were higher (49 ± 44 ng m^− 3). In blood, Mn concentrations averaged 10.1 ± 3.4 μg L^− 1 and 8% of children exceeded 15 μg L^− 1, the normal range. Mn concentrations fit a lognormal distribution. Heavier and Indian children had elevated levels. Pb in blood averaged 5.3 ± 2.1 μg dL^− 1, and 3.4% of children exceeded 10 μg dL^− 1, the guideline level. Pb levels were best fit by a mixed (extreme value) distribution, and boys and children living in industrialized areas of Durban had elevated levels. Although airborne Mn and Pb concentrations were correlated, blood levels were not. A trend analysis shows dramatic decreases of Pb levels in air and children's blood in South Africa, although a sizable fraction of children still exceeds guideline levels. The study's findings suggest that while vehicle exhaust may contribute to exposures of both metals, other sources currently dominate Pb exposures.     

Multiple site study of recent atmospheric metal (Pb, Zn and Cu) deposition in the NW Iberian Peninsula using peat cores

In order to estimate atmospheric metal deposition in Southern Europe since the beginning of the Industrial Period (~ 1850 AD), concentration profiles of Pb, Zn and Cu were determined in four ²¹⁰Pb-dated peat cores from ombrotrophic bogs in Serra do Xistral (Galicia, NW Iberian Peninsula). Maximum metal concentrations varied by a factor of 1.8 for Pb and Zn (70 to 128 μg g⁻¹ and 128 to 231 μg g⁻¹, respectively) and 3.5 for Cu (11 to 37 μg g⁻¹). The cumulative metal inventories of each core varied by a factor of 3 for all analysed metals (132 to 329 μg cm⁻² for Pb, 198 to 625 μg cm⁻² for Zn and 22 to 69 μg cm⁻² for Cu), suggesting differences in net accumulation rates among peatlands. Although results suggest that mean deposition rates vary within the studied area, the enhanced ²¹⁰Pb accumulation and the interpretation of the inventory ratios (²¹⁰Pb/Pb, Zn/Pb and Cu/Pb) in two bogs indicated that either a record perturbation or post-depositional redistribution effects must be considered. After correction, Pb, Zn and Cu profiles showed increasing concentrations and atmospheric fluxes since the mid-XX^th century to maximum values in the second half of the XX^th century. For Pb, maximum fluxes were observed in 1955-1962 and ranged from 16 to 22 mg m⁻² yr⁻¹ (mean of 18 ± 1 mg m⁻² yr⁻¹), two orders of magnitude higher than in the pre-industrial period. Peaks in Pb fluxes in Serra do Xistral before the period of maximum consumption of leaded petrol in Europe (1970s-1980s) suggest the dominance of local pollutant sources in the area (i.e. coal mining and burning). More recent peaks were observed for Zn and Cu, with fluxes ranging from 32 to 52 mg m⁻² yr⁻¹ in 1989-1996, and from 4 to 9 mg m⁻² yr⁻¹ in 1994-2001, respectively. Our results underline the importance of multi-core studies to assess both the integrity and reliability of peat records, and the degree of homogeneity in bog accumulation. We show the usefulness of using the excess ²¹⁰Pb inventory to distinguish between differential metal deposition, accumulation or anomalous peat records.     

Comparison of the microbiological and chemical characterization of harvested rainwater and reservoir water as alternative water resources

Rainwater harvesting (RWH) offers considerable potential as an alternative water supply. In this study, all of the harvested rainwater samples met the requirements for grey water but not for drinking water. In terms of microbiological parameters, total coliform (TC) and Escherichia coli (EC) were measured in 91.6% and 72%, respectively, of harvested rainwater samples at levels exceeding the guidelines for drinking water, consistent with rainfall events. In the case of the reservoir water samples, TC and EC were detected in 94.4% and 85.2%, respectively, of the samples at levels exceeding the guidelines for drinking water. Both indicators gradually increased in summer and fall. The highest median values of both TC and EC were detected during the fall. Chemical parameters such as common anions and major cations as well as metal ions in harvested rainwater were within the acceptable ranges for drinking water. By contrast, Al shows a notable increase to over 200 μg L^− 1 in the spring due to the intense periodic dust storms that can pass over the Gobi Desert in northern China. In terms of statistical analysis, the harvested rainwater quality showed that TC and EC exhibit high positive correlations with NO₃⁻ (ρ_TC = 0.786 and ρ_EC = 0.42) and PO₄⁻ (ρ_TC = 0.646 and ρ_EC = 0.653), which originally derive from catchment contamination, but strong negative correlations with Cl⁻ (ρ_TC = − 0.688 and ρ_EC = − 0.484) and Na⁺ (ρ_TC = − 0.469 and ρ_EC = − 0.418), which originate from seawater.     

The isotopic record of atmospheric lead fall-out on an Icelandic salt marsh since AD 50

We report a record of atmospheric Pb deposition at a coastal site in western Iceland that spans the last two millennia. The elemental concentrations of Pb, Al, Li and Ti are determined using ICP-MS from a sediment monolith collected from a salt marsh. Multicollector (MC) ICP-MS analysis is used to obtain isotopic ratios of stable Pb. The Pb/Ti and Pb/Li ratios are used to separate natural Pb background concentrations from Pb derived from remote anthropogenic sources. The pollution record in western Iceland is subdued in comparison with Pb records from the European mainland, but the isotopic character, profile and timing of Pb deposition show good agreement with the atmospheric Pb fall-out reported from sites in Scandinavia and northwestern Europe. At the bottom of the sequence we isolate a low-level (0.1-0.4 mg kg^− 1) Pb enrichment signal dated to AD 50-150. The isotopic signature and timing of this signal suggest Roman metal working industries as the source. In the subsequent millennium there was no significant or very low (i.e. elemental concentrations < 0.01 mg kg^− 1) anthropogenic Pb deposition at the site up to, and including, the early Medieval period. Above a pumice layer, dated to AD 1226-1227, a small increase in Pb deposition is found. This trend is maintained until a more substantive and progressive increase is signalled during the late 1700s and early 1800s. This is followed by a substantial enrichment signal in the sediments (> 3.0 mg kg^− 1) that is interpreted as derived from industrial coal burning and metal working during the 19th and 20th centuries in northern Europe. During the late 20th century, significant fall-out from European fuel additives reached Iceland.     

Investigating the potential role of ammonia in ion chemistry of fine particulate matter formation for an urban environment

To investigate the potential role of ammonia in ion chemistry of PM_2.5 aerosol, measurements of PM_2.5 (particulate matter having aerodynamic diameter < 2.5 µm) along with its ionic speciation and gaseous pollutants (sulfur dioxide (SO₂), nitrogen oxides (NO_x), ammonia (NH₃) and nitric acid (HNO₃)) were undertaken in two seasons (summer and winter) of 2007-2008 at four sampling sites in Kanpur, an urban-industrial city in the Ganga basin, India. Mean concentrations of water-soluble ions were observed in the following order (i) summer: SO₄²⁻ (26.3 µg m^− 3) > NO₃⁻ (16.8) > NH₄⁺ (15.1) > Ca²⁺ (4.1) > Na⁺ (2.4) > K⁺ (2.1 µg m^− 3) and (ii) winter: SO₄²⁻ (28.9 µg m^− 3) > NO₃⁻ (23.0) > NH₄⁺ (16.4) > Ca²⁺(3.4) > K⁺(3.3) > Na⁺ (3.2 µg m^− 3). The mean molar ratio of NH₄⁺ to SO₄²⁻ was 2.8 ± 0.6 (mostly >2), indicated abundance of NH₃ to neutralize H₂SO₄. The excess of NH₄⁺ was inferred to be associated with NO₃⁻ and Cl⁻. Higher sulfur conversion ratio (F_s: 58%) than nitrogen conversion ratio (F_n: 39%) indicated that SO₄²⁻ was the preferred secondary species to NO₃⁻. The charge balance for the ion chemistry of PM_2.5 revealed that compounds formed from ammonia as precursor are (NH₄)₂SO₄, NH₄NO₃ and NH₄Cl. This study conclusively established that while there are higher contributions of NH₄⁺, SO₄²⁻ to PM_2.5 in summer but for nitrates (in particulate phase), it is the winter season, which is critical because of low temperatures that drives the reaction between ammonia and HNO₃ in forward direction for enhanced nitrate formation. In summary, inorganic secondary aerosol formation accounted for 30% mass of PM_2.5 and any particulate control strategy should include optimal control of primary precursor gases including ammonia.     

Seasonal and diurnal variations of carbonyl compounds in the urban atmosphere of Guangzhou, China

Seasonal and diurnal variations of carbonyl compounds were investigated at two sampling sites (Liwan and Wushan) in the ambient air of Guangzhou, China. Air samples were collected during 2005 from January to November, and carbonyl compounds were analyzed with HPLC. The results show that carbonyls exhibit distinct seasonal variation. The total concentrations of 21 carbonyls detected ranged from 2.64 to 103.6 μg m⁻³ at Liwan and from 5.46 to 89.9 μg m⁻³ at Wushan, respectively. The average total concentrations of carbonyls at both Liwan and Wushan decreased in order of summer>spring>autumn>winter. Formaldehyde, acetaldehyde, and acetone were the most abundant carbonyl compounds, which accounted for more than 60% of the total concentrations of carbonyls. The mean concentration ratios of summer/winter were all > 1.0 for the total concentrations and the individual carbonyl compound. The diurnal variation of carbonyls was not distinct in this study. The average concentration ratios of formaldehyde/acetaldehyde (C₁/C₂) varied from 0.71 to 1.32 and 0.65 to 1.14 at Liwan and Wushan, respectively, and the average concentration ratios of acetaldehyde/propionaldehyde (C₂/C₃) varied from 5.42 to 7.70 and 5.02 to 13.9 in Liwan and Wushan, respectively. Regarding photochemical reactivity of carbonyls and the ozone production, acetaldehyde, butyraldehyde, formaldehyde, and valeraldehyde account for 75-90% to the total propene-equivalent concentrations, while formaldehyde, acetaldehyde, valeraldehyde, butyraldehyde, and propionaldehyde contribute 89-96% to the total ozone formation potentials (ranging from 105 to 274 μg m^-3). The ozone formation potentials in summer were higher by 1-2 times than those in the other seasons.     

Health risk from heavy metals via consumption of food crops in the vicinity of Dabaoshan mine, South China

Heavy metal contamination of soils resulting from mining and smelting is causing major concern due to the potential risk involved. This study was designed to investigate the heavy metal (Cu, Zn, Pb and Cd) concentrations in soils and food crops and estimate the potential health risks of metals to humans via consumption of polluted food crops grown at four villages around the Dabaoshan mine, South China. The heavy metal concentrations in paddy and garden soils exceeded the maximum allowable concentrations for Chinese agricultural soil. The paddy soil at Fandong village was heavily contaminated with Cu (703 mg kg^− 1), Zn (1100 mg kg^− 1), Pb (386 mg kg^− 1) and Cd (5.5 mg kg^− 1). Rice tended to accumulated higher Cd and Pb concentration in grain parts. The concentrations of Cd, Pb and Zn in vegetables exceeded the maximum permissible concentration in China. Taro grown at the four sampled villages accumulated high concentrations of Zn, Pb and Cd. Bio-accumulation factors for heavy metals in different vegetables showed a trend in the order: Cd > Zn > Cu > Pb. Bio-accumulation factors of heavy metals were significantly higher for leafy than for non-leafy vegetable. The target hazard quotient (THQ) of rice at four sites varied from 0.66-0.89 for Cu, 0.48-0.60 for Zn, 1.43-1.99 for Pb, and 2.61-6.25 for Cd. Estimated daily intake (EDI) and THQs for Cd and Pb of rice and vegetables exceeded the FAO/WHO permissible limit. Heavy metal contamination of food crops grown around the mine posed a great health risk to the local population through consumption of rice and vegetables.     

Influence of soil properties on trace element availability and plant accumulation in a Mediterranean salt marsh polluted by mining wastes: implications for phytomanagement

The aims of this study were to determine the factors which control metal and As phytoavailability in the different microenvironments (Sand Dunes, Salt Flat, Dry River and Shrubs) present at a Mediterranean salt marsh polluted by mining wastes. We performed a field study following a plot sampling survey. The analyses of soil parameters (pH, electrical conductivity (EC), organic carbon contents, etc.), total metal and As concentrations and their phytoavailability assessed with EDTA were related to each microenvironment and the corresponding plant species uptake. The averages of pH and EC were slightly alkaline (pH ≈ 7.5) and saline (≈ 2.2 to 17.1 dS m⁻¹) respectively. The soil samples from the Salt Flat subzone showed the highest metal concentrations (e.g. 51 mg kg⁻¹ Cd, 11,600 mg kg⁻¹ Pb) while for As, the highest concentrations occurred in the Dry River (380 mg kg⁻¹ As). The total metal and EDTA-extractable concentrations occurred as it follows: Salt Flat > Dry River > Degraded Dunes > Shrubs. In relation to plant metal and As accumulation, the highest root concentrations were obtained in the species from the Salt Flat subzone: ~ 17 mg kg⁻¹ As, ~ 620 mg kg⁻¹ Pb, for both, Juncus maritimus and Arthrocnemum macrostachyum. However the highest metal and As shoot concentrations occurred in species from the Sand Dunes: ~ 23 mg kg⁻¹ As ~ 270 mg kg⁻¹ Pb for Dittrichia viscosa; ~ 23 mg kg⁻¹ As, ~ 390 mg kg⁻¹ Zn for Crucianella maritima. The occurrence of edaphic gradients including salinity and texture determined the vegetation distribution. However, it cannot be concluded that there was a disturbance due to metal(loid)s soil concentrations in terms of vegetation composition except in the Degraded Dunes and Dry River. The higher EDTA-extractable concentrations were coincidental with the most saline soils but this did not result in higher metal(loid)s plant accumulation.     

Removal of Pharmaceutical and Personal Care Products (PPCPs) under nitrifying and denitrifying conditions

The contribution of volatilization, sorption and transformation to the removal of 16 Pharmaceutical and Personal Care Products (PPCPs) in two lab-scale conventional activated sludge reactors, working under nitrifying (aerobic) and denitrifying (anoxic) conditions for more than 1.5 years, have been assessed. Pseudo-first order biological degradation rate constants (k_biol) were calculated for the selected compounds in both reactors. Faster degradation kinetics were measured in the nitrifying reactor compared to the denitrifying system for the majority of PPCPs. Compounds could be classified according to their k_biol into very highly (k_biol > 5 L g_SS⁻¹ d⁻¹), highly (1 < k_biol < 5 L g_SS⁻¹ d⁻¹), moderately (0.5 < k_biol < 1 L g_SS⁻¹ d⁻¹) and hardly (k_biol < 0.5 L g_SS⁻¹ d⁻¹) biodegradable.Results indicated that fluoxetine (FLX), natural estrogens (E1 + E2) and musk fragrances (HHCB, AHTN and ADBI) were transformed to a large extent under aerobic (>75%) and anoxic (>65%) conditions, whereas naproxen (NPX), ethinylestradiol (EE2), roxithromycin (ROX) and erythromycin (ERY) were only significantly transformed in the aerobic reactor (>80%). The anti-depressant citalopram (CTL) was moderately biotransformed under both, aerobic and anoxic conditions (>60% and >40%, respectively). Some compounds, as carbamazepine (CBZ), diazepam (DZP), sulfamethoxazole (SMX) and trimethoprim (TMP), manifested high resistance to biological transformation.Solids Retention Time (SRT_aerobic >50 d and <50 d; SRT_anoxic >20 d and <20 d) had a slightly positive effect on the removal of FLX, NPX, CTL, EE2 and natural estrogens (increase in removal efficiencies <10%). Removal of diclofenac (DCF) in the aerobic reactor was positively affected by the development of nitrifying biomass and increased from 0% up to 74%. Similarly, efficient anoxic transformation of ibuprofen (75%) was observed after an adaptation period of 340 d. Temperature (16-26 °C) only had a slight effect on the removal of CTL which increased in 4%.     

Polybrominated diphenyl ethers, perfluorinated alkylated substances, and metals in tile drainage and groundwater following applications of municipal biosolids to agricultural fields

Polybrominated diphenyl ethers (PBDEs), perfluorinated alkylated substances (PFAS), and metals were monitored in tile drainage and groundwater following liquid (LMB) and dewatered municipal biosolid (DMB) applications to silty-clay loam agricultural field plots. LMB was applied (93,500 L ha^− 1) in late fall 2005 via surface spreading on un-tilled soil (SS_LMB), and a one-pass aerator-based pre-tillage prior to surface spreading (AerWay SSD) (A). The DMB was applied (8 Mg dw ha^− 1) in early summer 2006 on the same plots by injecting DMB beneath the soil surface (DI), and surface spreading on un-tilled soil (SS_DMB). Key PBDE congeners (BDE-47, -99, -100, -153, -154, -183, -209) comprising 97% of total PBDE in LMB, had maximum tile effluent concentrations ranging from 6 to 320 ng L^− 1 during application-induced tile flow. SS_LMB application-induced tile mass loads for these PBDE congeners were significantly higher than those for control (C) plots (no LMB) (p < 0.05), but not A plots (p > 0.05). PBDE mass loss via tile (0-2 h post-application) as a percent of mass applied was ~ 0.04-0.1% and ~ 0.8-1.7% for A and SS_LMB, respectively. Total PBDE loading to soil via LMB and DMB application was 0.0018 and 0.02 kg total PBDE ha^− 1 yr^− 1, respectively. Total PBDE concentration in soil (0-0.2 m) after both applications was 115 ng g^− 1 dw, (sampled 599 days and 340 days post LMB and DMB applications respectively). Of all the PFAS compounds, only PFOS (max concentration = 17 ng L^− 1) and PFOA (12 ng L^− 1) were found above detectable limits in tile drainage from the application plots. Mass loads of metals in tile for the LMB application-induced tile hydrograph event, and post-application concentrations of metals in groundwater, showed significant (p < 0.05) land application treatment effects (SS_LMB > A > C for tile and SS_LMB and A > C for groundwater for most results). Following DMB application, no significant differences in metal mass loads in tile were found between SS_DMB and DI treatments (PBDE/PFAS were not measured). But for many metals (Cu, Se, Cd, Mo, Hg and Pb) both SS_DMB and DI loads were significantly higher than those from C, but only during < 100 days post DMB application. Clearly, pre-tilling the soil (e.g., A) prior to surface application of LMB will reduce application-based PBDE and metal contamination to tile drainage and shallow groundwater. Directly injecting DMB in soil does not significantly increase metal loading to tile drains relative to SS_DMB, thus, DI should be considered a DMB land application option.     

Atmospheric transport of water-soluble ions (NO3, NH4 and nss-SO4) to the southern East Sea (Sea of Japan)

Atmospheric deposition of different types of aerosols over the southern East Sea has received little attention in terms of seawater biogeochemistry. We investigated the concentrations of water-soluble ions (NO₃⁻, NH₄⁺ and nss-SO₄²⁻) in the aerosols associated with air mass transport patterns arriving at the east coast of Korea, adjacent to the southern East Sea, in order to determine source regions affecting chemical composition of aerosols and to assess the atmospheric pathway as a significant controlling mechanism of the biogeochemistry in this marginal sea. Concentrations of certain elements (Al, Na, Ca, V, Zn and Pb) together with the water-soluble ions were measured in the aerosol samples (n = 34) collected during the period March 2002-February 2003. The geometric mean concentrations of the water-soluble ions were NO₃⁻ 2.98 (0.56-16.22), NH₄⁺ 1.42 (0.37-6.73) and nss-SO₄²⁻ 2.47 (0.17-17.35) μg m^− 3. The backward trajectories revealed that air masses passing slowly over eastern China contributed more to increases in the concentrations of water-soluble ions than those associated with fast-moving northwesterly and maritime winds. Therefore, the correlation between the NH₄⁺ and NO₃⁺ concentrations increased, suggesting that gas-phase NH₃ and HNO₃ was forming fine-mode NH₄NO₃. The atmospheric N input accounted for ∼ 10% of new production over the southern East Sea on an annual scale, while it accounted for over ∼ 25% of new production during the water column stratification seasons (summer and early fall).     

Photochemical generation of reactive species upon irradiation of rainwater: Negligible photoactivity of dissolved organic matter

This paper focuses on the study of the photochemical activity of dissolved organic matter present in rainwater. Formation rates of the reactive species hydroxyl radical (OH^•), singlet oxygen (¹O₂) and dissolved organic matter triplet states (³DOM^?) were determined by irradiation (UV-A) of wet-only rainwater samples collected in Turin (Italy) in the presence of specific scavengers (benzene, furfuryl alcohol and phenol, respectively). Photo-formation rates of OH^• (≈ 3 · 10⁻¹¹ M s⁻¹) and ¹O₂ (≈ 10⁻¹⁴ M s⁻¹) were lower (1 or 2 orders of magnitude) or largely lower (4 to 10 orders of magnitude) than those determined for fog and cloud samples in previous studies. ³DOM^? formation rate values were either negligible or quite low (≈ 10⁻¹² M s⁻¹) by comparison with those evaluated for surface water samples. Deduced steady-state [OH^•] were in the same range as those reported for fog samples in the literature (8.7 · 10⁻¹⁶ to 1.5 · 10⁻¹⁵ M), while [¹O₂] was often several orders of magnitude lower and, therefore, could be considered as negligible. Nitrite (NO₂⁻) constituted the main source of OH^• (69 ± 21 to 138 ± 36%), and the deduced contribution of DOM was low or nil. All the results obtained in this study tend to demonstrate that DOM (including HUmic LIke Substances, HULIS) present in rainwater is poorly or not photoactive. Therefore, there could be considerable difference between rainwater DOM (HULIS included) and the organic matter present in surface waters, particularly the humic substances, as far as the photochemical activity is concerned.     

Distribution of Pb and Po concentrations in wild berries and mushrooms in boreal forest ecosystems

The activity concentrations and distribution of ²¹⁰Pb and ²¹⁰Po in wild berries and edible mushrooms were investigated in Finnish forests. The main study areas were located in Scots pine (Pinus sylvestris L.) forests in southern and northern Finland. The activity concentrations of ²¹⁰Pb and ²¹⁰Po in blueberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.) samples decreased in the order: stems > leaves > berries (i.e. fruits). The activity ratios of ²¹⁰Po/²¹⁰Pb in the wild berry samples were mainly higher than one, indicating elevated activity concentrations of polonium in the samples. In mushrooms the activity concentrations of ²¹⁰Pb and especially ²¹⁰Po were higher than in fruits of the wild berries. The highest activity concentration of ²¹⁰Pb was detected in Cortinarius armillatus L. (16.2 Bq kg^− 1 d.w.) and the lowest in Leccinum vulpinum L. (1.38 Bq kg^− 1 d.w.). The ²¹⁰Po activity concentrations of the whole fruiting bodies ranged from 7.14 Bq kg^− 1 d.w. (Russula paludosa L.) to 1174 Bq kg^− 1 d.w. (L. vulpinum L.). In general, the highest activity concentrations of ²¹⁰Po were recorded in boletes. The caps of mushrooms of the Boletaceae family showed higher activity concentrations of ²¹⁰Po compared to the stipes. In most of the mushrooms analyzed, the activity concentrations of ²¹⁰Po were higher than those of ²¹⁰Pb. ²¹⁰Po and ²¹⁰Pb dominate the radiation doses received via ingestion of wild berries and mushrooms in northern Finland, while in southern Finland the ingested dose is dominated by ¹³⁷Cs from the Chernobyl fallout.