Acid deposition near a sour gas plant in southwestern Alberta

Atmospheric fallout in the vicinity of a sour gas plant in southwestern Alberta was collected on an event basis with bulk precipitation collectors during June, July and August of 1972, 1973 and 1982. Samples were collected at 9 sites within 20 km of the plant. Total atmospheric sulfation measurements defined a higher exposure area located downwind of the plant, but the precipitation measurements did not. Bulk deposition of H⁺ ion in the study area was an average 10.77 mmol H⁺ m^?2 3 mol^?1 in 1972 and 0.014 and 0.049 in 1973 and 1982, respectively. 1972 samples were also significantly more acidic (average pH of 4.3 vs 5.7 in 1973 and 5.3 in 1982). Deposition of SO₄ ⁼ averaged 2.1 kg S ha^?1 3 mol^?1 in 1972 and 0.96 and 0.72 in 1973 and 1982. The higher deposition of both S and H⁺ in 1972 is mainly a result of more precipitation. There was no significant correlation between H⁺ and SO₄ ⁼ species in the samples. There was no significant relationship between plant S emissions and deposition rates, or plant S emissions and average total atmospheric sulfation measurements.     

Sulphur in air and soil

Natural S supplies are insufficient for high crop yields. The S brought down by rain is limited, even in industrial areas, and much of it is lost in drainage. Additional supplies are needed either as fertilizers or as SO₂, which vegetation readily absorbs. The margin between the minimum SO₂ concentration for full growth and the concentration at which damage occurs is wide enough for distribution via the air, without deleterious effects, of such S as is available from the combustion of fuels.     

Observations of pH in field soils near a sour gas plant in Alberta

Soil pH was observed in natural soil profiles over 9 yr near a sour gas plant in southern Alberta. Samples were collected during the spring and fall from 1973 to 1981 at 10 replicated sites. No acidification trend in pH was observed.     

Interdependence of air,water, and soil pollution control strategies in a power plant and a kraft mill

An analysis of cross-media (air, water, and soil) emissions resulting from various control strategies is necessary in the evaluations of emission standards as well as control strategies. This paper presents such analysis on seven control strategies for a coal-fired power plant and ten control strategies for a kraft pulp and paper mill. The data illustrated include uncontrolled and controlled emissions to all three environmental media as well as power requirement, and capital and operating costs.     

Simultaneous determination of alachlor, metolachlor, atrazine, and simazine in water and soil by isotope dilution gas chromatography/mass spectrometry

A multiresidue method was developed for the simultaneous determination of low parts per billion (ppb) concentrations of the herbicides alachlor, metolachlor, atrazine, and simazine in water and soil using isotope dilution gas chromatography/mass spectrometry (GC/MS). Known amounts of 15N,13C-alachlor and 2H5-atrazine were added to each sample as internal standards. The samples were then prepared by a solid phase extraction with no further cleanup. A high resolution GC/low resolution MS system with data acquisition in selected ion monitoring mode was used to quantitate herbicides in the extract. The limit of detection was 0.05 ppb for water and 0.5 ppb for soil. Accuracy greater than 80% and precision better than 4% was demonstrated with spiked samples.     

Oxygen isotope ratios of juice water in Australian oranges and concentrates.

Australian orange juices from major growing regions have been surveyed over a 5 year period with a view to establishing a database of (18)O/(16)O isotope ratios against which retail samples can be tested for authenticity. The (18)O/(16)O ratios were found to follow a consistent pattern that had both a cyclic seasonal and a regional influence. Oxygen delta values ranged from a summer maximum of >+15 per thousand for oranges from inland regions to a winter minimum of approximately +1 per thousand for oranges grown in coastal areas. However, over a shorter time period, the range of values was markedly less than this. Concentrated orange juices, pulpwashes, and peel extracts, as well as other citrus types, were also tested. The effect of some industry practices that have an effect on (18)O/(16)O ratios was also investigated.     

Determination of 129i in water and air samples near a reprocessing plant by neutron activation analysis

The neutron activation analysis was used to determine ¹²⁹I in water and air samples collected in the neighbourhood of a reprocessing plant. The method involved preconcentration of ¹²⁹I on AgI from water samples, separation of Ag⁺, followed by distillation, loading on Dowex-1, irradiation and post irradiation purification steps. Filter air samples were wet oxidised follwed by distillation and other chemical procedure steps as described for water samples. The concentration of ¹²⁹I in rain water and air samples ranged from 0.155×10^?3 to 0.327×10^?3 Bq L^?1 and 0.054×10^?6 to 0.295×10^?6 Bq m^?3 respectively. The average concentration of ¹²⁹I in seawater samples was 0.157×10^?3 Bq L^?1. The concentration of ¹²⁹I obtained in these samples have been translated to dose rates to an individual and have been found to be insignificant.     

Leaf injury and elemental concentrations in vegetation near a coal-fired power plant

Leaf injury of two native grasses, needleandthread (Stipa comata Trin. & Rupr.) and prairie sandreed (Calamovilfa longifolia [Hook.] Scribn.), and plains cottonwood (Populus sargentiii Dode) were slightly greater in a downwind direction from a coal-fired power plant in central Wyoming. Injury usually increased with proximity to the power station. A controlled experiment utilizing pinto beans (Phaseolus vulgaris L.) grown within phytometers also indicated greatest leaf injury near and downwind from the power station. Elevated levels of Fe and fluoride in foliage samples were found for plants growing near the power station and in a downwind direction. However, no significant increases in Hg, Pb, and Cd were found for plants growing near the power plant. Significant positive correlations were found for leaf injury and the Fe and fluoride concentrations of foliage with average daily sulfation rates. However, no significant correlation between sulfation rates and sulfate concentrations in foliage was found. It is suspected, therefore, that SO₂ may act synergistically with fluorides or other emission products, resulting in the slightly elevated leaf injury downwind from the power station.     

Mercury pollution of effluent,air, and soil near a battery factory in Tanzania

Effluent, air, and soil samples near a battery factory in Dar es Salaam, Tanzania, where HgCl₂ is used to prevent mold growth, were collected to explore the potential for pollution of the environment from industrial discharge of Hg. Flameless atomic absorption spectrophotometry was used for Hg determinations. The concentration of Hg in the effluent ranged from <0.2 to 5.2 mg L^?1 and the Hg concentration varied greatly within and among sampling days, showing different peaks. Air contained a mean of 4.0 μg m^?3 with little variation within and between sampling days. Soils near the factory contained high Hg levels, from 6.7 to 472 mg kg^?1 in the immediate vicinity, the highest level being associated with disposal of solid waste (defective batteries). Downwind the concentration of Hg decreased with increasing distance from the factory resulting in a soil concentration of 1.0 mg Hg kg^?1 about 2 km away. Upwind the Hg concentration decreased drastically within a distance of 100 to 200 m.     

PCDD and PCDF in air,soil, vegetation and oily runoff from a tire fire

In early February 1990, vandals set fire to a used tire storage facility near Hagersville, Ontario, Canada, During the fire, the Ontario Ministry of Environment and Energy (MOEE) monitored the site and surrounding impact zone for numerous organic contaminants. Samples of air, soil, vegetation, runoff water, and oily residue were collected and analyzed for polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). Air samples produced complex incineration patterns with a large number of isomers detected. Total toxicity equivalents (TEQ) at 1 km downwind of the fire were an order of magnitude higher than those at 3 km downwind. Soil samples collected during the fire did not show elevated PCDD or PCDF concentrations, however, low concentrations were detected in vegetation collected at 100 m and 200 m from the site. PCDD and PCDF concentrations in the foliage decreased with time but were still detectable for at least 200 days after the fire started. As the tires burned, water used to extinguish the fire caused runoff of oil and oily water. Unique patterns of PCDDs and PCDFs were detected in these samples.     

Oxygen isotope ratios of plant available phosphate in lowland tropical forest soils

Phosphorus (P) cycles rapidly in lowland tropical forest soils, but the process have been proven difficult to quantify. Recently it was demonstrated that valuable data on soil P transformations can be derived from the natural abundance of stable oxygen isotopes in phosphate (δ¹⁸O_P). Here, we measured the δ¹⁸O_P of soils that had received long-term nutrient additions (P, nitrogen, and potassium) or litter manipulations in lowland tropical forest in Panama and performed controlled incubations of fresh soils amended with a single pulse of P. To detect whether δ¹⁸O_P values measured in the incubations apply also for soils in the field, we examined the δ¹⁸O_P values after rewetting dry soils. In the incubations, resin-P δ¹⁸O_P values converged to ∼3.5‰ above the expected isotopic equilibrium with soil water. This contrasts with extra-tropical soils in which the δ¹⁸O_P of resin-P matches the expected equilibrium with soil water. Identical above-equilibrium resin-P δ¹⁸O_P values were also found in field soils that did not receive P additions or extra litter. We suggest that the 3.5‰ above-equilibrium δ¹⁸O_P values reflect a steady state between microbial uptake of phosphate (which enriches the remaining phosphate with the heavier isotopologues) and the release of isotopically equilibrated cell internal phosphate back to the soil. We also found that soil nutrient status affected the microbial turnover rate because in soils that had received chronic P addition, the original δ¹⁸O_P signature of the fertilizer was preserved for at least eight weeks, indicating that the off-equilibrium δ¹⁸O_P values produced during microbial phosphate turnover was not imprinted in these soils. Overall, our results demonstrate that ongoing microbial turnover of phosphate mediates its biological availability in lowland tropical soils.     

The influence of three sour gas processing plants on the ecological distribution of epiphytic lichens in the vicinity of fox creek and Whitecourt,Alberta, Canada

The ecological distributions of epiphytic lichens have been reduced by SO₂ emissions from three sour gas processing plants located near Fox Creek and Whitecourt, Alberta. Pollutants tend to concentrate in drainage channels leading to the Athabasca River. These channels parallel the prevailing wind. No sites were encountered which totally lacked lichens but at sites within 1 to 2 km downwind of gas plants and associated S storage blocks, the epiphytic lichen flora was reduced in variety, cover and vitality. An Index of Atmospheric Purity (IAP) was calculated from epiphyte data using selected indicator species and air pollution zones determined. Zone maps of relative air purity were generated using the SYMAP mapping package. Improvements to previous IAP methodologies are suggested. Average sulfation rates, S content, and stable S isotope abundance ratios are discussed as they relate to lichen diversity, vitality and IAP values.     

Impact of thermal power plant emissions on vegetation and soil

Studies were made to assess the impact of a thermal power plant located at Obra on vegetation and soil in surrounding areas. Pollutant concentration in the area gradually decreased along a belt in the prevailing wind direction and a gradient of structural and functional changes in plants and soil was observed. Natural vegetation in the area varied significantly at different sites and on the basis of plant responses can be classified as insensitive, intermediate and sensitive.

The effect of the power plant emissions on soil and eco-physiological characteristics such as pH, organic matter and N, P, K and S concentrations in soil; leaf injury symptoms, number and distribution of plant species; chlorophyll content in leaves, percentages of photosynthetically active leaf area; accumulation of N, P, K, and S in leaves etc. seemed to be a function of the pollutant gradient existing in the area. There was a relationship between plant responses and changes in the chemical factors of soil and plants due to pollution. This study indicates possible elimination of plant species, first the trees then the shrubs and lastly the herbs and grasses from the environs of the thermal power plant. The increase in soil acidity in the area may cause cation-anion imbalance and microbe population reduction to affect soil fertility.

     

Sulphur immobilization and availability in soils assessed using isotope dilution

Increasing recognition of S deficiency in soils has raised the need for understanding processes governing S cycling and availability in soils. However, the quantification of the two main processes of S cycling, i.e. mineralization and immobilization, remains difficult as these processes occur simultaneously. A modified isotope ³⁵SO₄ dilution technique was developed and used to measure the effect of sulphate (SO₄) fertilization on S mineralization and immobilization in planted (pot experiment with ryegrass (Lolium multiflorum L.)) and unplanted soils (incubation). The immobilization and mineralization of S was calculated from the dynamics of stable and labelled S in soil KH₂PO₄ extracts containing an anion exchange membrane that concentrates SO₄ and mainly excludes other S species. The mathematical analysis of the isotope dilution data differs from methods proposed earlier. The radiolabile S in unplanted soil (E value) and in ryegrass (L value) were used as a measure of total available S in soils. Sulphate immobilization rate significantly declined during incubation. Sulphate application reduced gross mineralization but surprisingly reduced SO₄ immobilization. The E value significantly increased during the incubation in all soils as a result of gross mineralization, e.g. from 3.8 mg S kg⁻¹ at day 0 to 11.5 mg S kg⁻¹ at day 43 in the sandy soil with no sulphate addition. A full recovery in the E value of S added in (+S) treatments was achieved. Similarly, radiolabile S in the above-ground ryegrass biomass (L value) increased with S addition, with a full recovery of added S. The E and L values nearly fit a 1:1 line suggesting identical S dynamics in a planted and unplanted soil. The method proposed has operational advantages compared to methods used earlier.     

川北紫色土小流域植被建设的水土保持效应

定量评价林草植被的水土保持功能对合理指导紫色土区的流域综合治理具有重要作用。该研究基于鹤鸣观流域Ⅱ号支沟1985-2001年逐日径流量和输沙量,结合实测日降雨量,采用Spearman秩相关统计法分析流域径流和输沙变化趋势,应用流量历时曲线和双累积曲线分析流域植被建设实施前后径流和输沙变化特征,并定量评估植被建设的水土保持效应。结果表明:结合防护林营造时间和双累积曲线分析,把水文序列分为基准期(1985-1990年)和评价期(1991-2001年),相比基准期,评价期小流域的年均降水量减少约8.1%,而年径流深和年输沙模数却分别减少34.6%和89.9%,说明以植被建设为主的人类活动起到重要作用。同时,植被建设的削洪增枯效果明显,评价期的丰水日径流深和平水日径流深较基准期分别减少了84.2%和76.3%,而枯水日径流深却增加了650.0%;结合双累积曲线和分离判别法可知,植被建设在径流和输沙变化中的贡献率分别达92.9%和94.3%,大规模的植被建设在减少土壤侵蚀的同时也减少了产流量,考虑到水安全问题,未来植被建设应合理规划。     

The influence of vegetation and soil type on the speciation of iron in soil water

Soluble organic matter derived from exotic Pinus species has been shown to form stronger complexes with iron (Fe) than that derived from most native Australian species. It has also been proposed that the establishment of exotic Pinus plantations in coastal southeast Queensland may have enhanced the solubility of Fe in soils by increasing the amount of organically complexed Fe, but this remains inconclusive. In this study we test whether the concentration and speciation of Fe in soil water from Pinus plantations differs significantly from soil water from native vegetation areas. Both Fe redox speciation and the interaction between Fe and dissolved organic matter (DOM) were considered; Fe – DOM interaction was assessed using the Stockholm Humic Model. Iron concentrations (mainly Fe²⁺) were greatest in the soil waters with the greatest DOM content collected from sandy podosols (Podzols), where they are largely controlled by redox potential. Iron concentrations were small in soil waters from clay and iron oxide‐rich soils, in spite of similar redox potentials. This condition is related to stronger sorption on to the reactive clay and iron oxide mineral surfaces in these soils, which reduces the amount of DOM available for electron shuttling and microbial metabolism, restricting reductive dissolution of Fe. Vegetation type had no significant influence on the concentration and speciation of iron in soil waters, although DOM from Pinus sites had greater acidic functional group site densities than DOM from native vegetation sites. This is because Fe is mainly in the ferrous form, even in samples from the relatively well‐drained podosols. However, modelling suggests that Pinus DOM can significantly increase the amount of truly dissolved ferric iron remaining in solution in oxic conditions. Therefore, the input of ferrous iron together with Pinus DOM to surface waters may reduce precipitation of hydrous ferric oxides (ferrihydrite) and increase the flux of dissolved Fe out of the catchment. Such inputs of iron are most probably derived from podosols planted with Pinus.     

Cycling of mercury between water,air, and soil compartments of the environment

The propensity to resist chemical, photo-chemical or biological degradation processes, coupled with a high degree of mobility — due to favorable physical-chemical properties such as relatively high vapor pressure and low solubility in water - bestows upon some chemical substances the necessary pre-requisites for extensive cycling among environmental compartments. Certain inorganic and organometallic species of Hg exhibit the aforementioned characteristics. This paper presents field measurement data, collected in Canada and Sweden, that provide information concerning the direction and magnitude of the material fluxes associated with transfer processes of Hg in the natural environment. The results of the field measurements reported here point to the importance of the natural phenomena of emission or re-emission (i.e., volatilization processes) involving the release of volatile Hg species from lake and soil surfaces into the overlying air, at least under warm weather conditions. Consequently, volatilization fluxes of Hg from natural surfaces should be taken into account when constructing biogeochemical cycles for this element and when calculating mass balances or budgets for Hg on local, regional and global scales.     

Effects of mulch location on banana weevil,soil and plant nutrients,soil water and biomass in banana fields

Major constraints to banana (Musa spp., genome group AAA) production, a dietary staple for over 70 million people in sub-Saharan Africa, are pest infestations, poor nutrition and inadequate water. Although mulch can improve soil water and nutrient status, many farmers believe it also promotes the proliferation of banana weevil (Cosmopolites sordidus), one of the most serious banana pests. In this study, we evaluated the effects of mulch location (mulch to base of banana pseudostem; mulch recessed 1 m from the pseudostem) on banana weevil, soil and plant nutrient status, soil water, and banana growth and development. After 3 years, the fully mulched plots had significantly more soil Ca and Mg than plots that did not receive mulch. Banana foliar K concentration was significantly higher in both mulch treatments (full and recessed) than in the control (no mulch) plots. The mulched plots had greater recharge after rainfall events and higher soil water contents during dry periods due to increased infiltration in the mulched plots. However, the mulched plots also exhibited significantly higher banana weevil densities and greater plant damage than the control plots. There was no difference in weevil damage with mulch location, although weevil density was higher in the fully mulched plots throughout most of the trial. Despite greater weevil damage, the treatments that were mulched yielded significantly heavier bunches. Hence the effects of the mulch on soil water infiltration and banana foliar nutrient status outweighed the detrimental effects of banana weevil damage.     

Community composition and activities of denitrifying bacteria from adjacent agricultural soil, riparian soil, and creek sediment in Oregon, USA

We examined denitrifying bacteria from wet soils and creek sediment in an agroecosystem in Oregon, USA that received inputs of nitrogen (N) fertilizer. Our objective was to determine the variation in denitrifying community composition and activities across three adjacent habitats: a fertilized agricultural field planted to perennial ryegrass, a naturally vegetated riparian area, and creek sediment. Using C₂H₂ inhibition, denitrifying enzyme and N₂O-reductase activities were determined in short-term incubations of anaerobic slurries. A key gene in the denitrification pathway, N₂O reductase (nosZ), served as a marker for denitrifiers. Mean denitrifying enzyme activity (DEA) was similar among habitats, ranging from 0.5 to 1.8 μg N g⁻¹ dry soil h⁻¹. However, the ratio of N₂O production, without C₂H₂, to DEA was substantially higher in riparian soil (0.64±0.02; mean±standard error, n=12) than in agricultural soil (0.19±0.02) or creek sediment (0.32±0.03). Mean N₂O-reductase activity ranged from 0.5 to 3.2 μg N g⁻¹ dry soil h⁻¹, with greater activity in agricultural soil than in riparian soil. Denitrifying community composition differed significantly among habitats based on nosZ terminal-restriction fragment length polymorphisms. The creek sediment community was unique. Communities in the agricultural and riparian soil were more closely related but distinct. A number of unique nosZ genotypes were detected in creek sediment. Sequences of nosZ obtained from riparian soil were closely related to nosZ from Bradyrhizobium japonicum. Although nosZ distribution and N₂O-reductase activity differed among habitats, relationships between activity and community composition appeared uncoupled across the agroecosystem.