Water Quality Characterization in the Northern Florida Everglades

The Loxahatchee National Wildlife Refuge (Refuge) developed as a system with waters low in nutrients. Today, the Refuge wetlands are impacted by inflows containing elevated nutrient concentrations originating from agricultural sources flowing into canals surrounding the west side and from urban and horticultural areas flowing into canals surrounding the eastern side of the Refuge. We analyzed water quality sampled at 40 sites divided into eastern and western areas and four zones in the Refuge. We defined four zones as the canals surrounding the Refuge marsh, the perimeter zone, the transition zone, and the interior zone. The canal receiving agricultural inflows had greater alkalinity and conductivity (SpC), Si and SO₄ but lower turbidity and total suspended solids than the canal receiving urban and horticultural inflows. Alkalinity, total dissolved solids (TDS), SpC, Ca, Cl, and SO₄ concentrations were greater in the perimeter than in transition and interior zones. Alkalinity and SpC values and SO₄ concentrations were greater in the transition than in interior zone. Alkalinity, SpC, and TDS values and Ca, SO₄, and Cl concentrations correlated in negative curvilinear relationships with distance from the canal (r ²?=?0.78, 0.70, 0.61, 0.78, 0.64, 0.57, respectively). Analysis of multiple water quality parameters may reveal the complexity of interactions that might be overlooked in a simple single parameter analysis. These data show an impact of canal water containing high nutrient concentrations on water quality flowing from the canal towards the Refuge interior.     

The Efficacy of the Four-Part Test Network to Monitor Water Quality in the Loxahatchee National Wildlife Refuge

The Loxahatchee National Wildlife Refuge (Refuge) is impacted by inflows containing elevated contaminant concentrations originating from agricultural and urban areas. Water quality was analyzed using the Enhanced Refuge (ERN), the four-part test (FPTN), and the Consent Decree (CDN) monitoring networks within four zones in the Refuge. The zones were defined as the canal surrounding the marsh, the perimeter, the transition, and the interior zones. Although regression coefficients for ALK and SpC, and Ca, Cl, and SO₄ concentrations with distance from the canal were lower using the FPTN than when using the ERN, using the FPTN to measure water quality parameters in the Refuge would give similar results as the ERN. Most of the ERN and FPTN sites are located in the northern and central areas of the Refuge. Water is deeper in the southern Refuge, and on an area basis contains a greater volume of water than the northern and central Refuge and therefore, water flow from the canal into the marsh in the northern and southern Refuge may differ. Numerous water quality monitoring sites must be added to the ERN and FPTN in the southern area to characterize water quality in the southern Refuge with confidence.     

Water Quality Trends in the Loxahatchee National Wildlife Refuge

The Loxahatchee National Wildlife Refuge (Refuge) developed throughout millennia as a system with waters low in nutrients. Today, the Refuge wetlands are impacted by inflows containing elevated nutrient concentrations originating from agricultural sources. Surface water samples were collected monthly at 48 marsh and five canal sites from June, 2004 through May, 2011 and analyzed water quality trends by sampling perimeter, transition, and the interior zones based on distance from the canal towards the Refuge interior. Nutrient, inorganic ion, and C concentrations generally decreased with distance from the canal to the Refuge interior. These water quality parameters also decreased from the canal to the Refuge interior, but less sharply. This finding suggests that there has been less canal water intrusion into the Refuge during the sampling period. The origin of the high Ca and Cl concentrations in canal water is most likely from intrusion of connate seawater into the canal. The reason for the improved water quality from June, 2004 to June 2011 can be attributed to an improved STA1-East performance since 2005. Additionally, canal water that originally by-passed treatment in STA1-East and STA1-West, and flowed into the L-7 canal through the S-6 pump, is now diverted farther south into STA2 for treatment.     

Amino acid, carbohydrate, and fat composition of soybean meals prepared at 55 commercial U.S. soybean processing plants

To quantify variation in U.S. soybean meals (SBM), samples were collected from 55 U.S. soybean (SB) processing plants located in seven of the geographic SB maturity zones at three time points. These samples were analyzed for crude and acid-hydrolyzed fat, oligosaccharide, and amino acid concentrations. Acid-hydrolyzed fat concentrations were poorly correlated (r = 0.28) to crude fat concentrations and were higher for SBM prepared in the southern zones (V-VII) as compared with the northern zones (I and II). Raffinose and verbascose concentrations were lowest (P < 0.05) for SBM prepared in northern maturity zones, while stachyose concentrations were highest for SBM prepared in central maturity zones (III and IV). Total essential, total nonessential, and total amino acid concentrations were lowest for SBM prepared in northern zones. There was variation in oligosaccharide and amino acid concentrations over time, probably due to variation in composition of SB arriving at the plants within maturity zone.     

Temporal and Spatial Variations in Soil Water Chemistry at Three Acid Forest Sites

As acid deposition declines, recovery from acidification is delayed by the fact that the soil processes that earlier buffered against acidification are now being reversed. Monitoring of within catchment processes is thus desirable. However, soil sampling is destructive and not suitable for long-term monitoring at a single site, whereas sampling of soil water with suction lysimeters may be more suitable. In this paper we evaluate 8–11 years of soil water chemistry from E- and B-horizons in three acid forest soil plots within monitored catchments. Five years of sampling also included the C-horizon. To our knowledge, this is the first long-term lysimeter study including the E-horizon showing recovery from acidification, and one of few studies including the B-horizon. Soil water concentrations of SO₄ decreased significantly between –9.5 and –1.4 μeq L^-1 yr^-1, with much higher rates of change at two southern sites compared to a northern site, where levels and changes of deposition were lower. The average annual bulk deposition of S ranged between 3 kg S ha^-1 at the northernmost site to 11 kg S ha^-1 at the southernmost site. The SO₄ decline in E-horizons was smaller than the decline in deposition, which indicated leaching of SO₄ from the O-horizon. At the two southern sites, a weaker decline in SO₄ in the B-horizon compared to the E-horizon indicated desorption of SO₄. The negative trends in SO₄ were to a large extent balanced by decreases in base cations but there were also tendencies of recovery from acidification in soil solution at the southern sites by increasing pH and ANC. However, these were contradicted by increasing Al concentrations. A high influence of marine salts in the early 1990s may have delayed the recovery. Decreasing trends of the Ca/(H⁺)² ratio in the soil solution, most pronounced at one of the southern sites, suggested that the soils were becoming more acidic, although the soil solution tended to recover.     

Effects of the 921 earthquake on the water quality in the upper stream at the Guandaushi experimental forest

A powerful 7.3 magnitude earthquake struck Taiwan on September 21, 1999. The stream water chemistry (pH, total alkalinity, conductivity, sodium, potassium, calcium, magnesium, ammonium, fluoride, chloride, sulfate, and nitrate) has been monitored since 1995 at the Guandaushi forestry riparian zone in central Taiwan. Collected data was used as a basis for comparing pre- and post-earthquake impacts. The pH, conductivity, and concentrations of Na, Ca, Mg, SO₄, and HCO₃ in stream water were lowest during the summer season, when stream water discharge was highest. On the other hand, the lowest concentrations of Cl, NH₄, and NO₃ in stream water occurred during the winter season, when stream water discharge was lowest. Also, K and F showed very little seasonal fluctuation in concentration. Downward trends in K and Ca were found 14 months prior to the earthquake; although, an upward trend occurred in NH₄ at the same time.     

Relations between lake acidification and sulfate deposition in Northern Minnesota,Wisconsin, and Michigan

From a level of 1 kg ha^?1yr^?1 in north central Minnesota, emission-related wet SO₄ deposition increases across northern Wisconsin and northern Michigan to about 18 kg ha^?1yr^?1 in south central Michigan. Samples taken from 82 clearwater (low color) lakes across this region in the summer of 1984 showed a pattern of acidification in proportion to deposition. We found a linear increase in the difference between alkalinity and Ca+Mg and in lake SO₄ concentration with increasing deposition. We developed a simple equation to predict the emission-related SO₄ deposition levels that will cause the alkalinity of sensitive clear-water lakes to go to zero.     

Evaluation of the changes in regional wintertime deposition in Finland during 1976–1993

Snowpack quality has been systematically monitored in Finland since winter 1975/1976 by the Finnish Environment Agency. Snow samples have been taken at the 53 groundwater observation stations in nearly natural state areas, where the impacts of local emission sources have been negligible. Thus the concentrations of impurities in snow can be considered as background levels. Samples were analyzed for conductivity, pH, major ions and trace metals (Cd, Cu, Pb, Ni, Zn and Hg). The regional variation of the chemical composition of major ions in the snowpack was outlined by cluster analysis. Sampling sites were divided into six clusters by average linkage clustering method. The largest cluster — considered as the ‘mean cluster’ — was located in central and northern Finland. The lowest levels of the total amount of dissolved impurities occurred in the cluster formed by the most northern observation site exclusively. Highest rates of the acidifying components, sulphate (SO₄), nitrate (NO₃), ammonium (NH₄) and hydrogen ions (H⁺), were encountered in southern Finland. Sampling locations of southern Finland were divided into three clusters. The acidity of snow varies among these clusters that in addition of deposition of SO₄ and NO₃ is considerably controlled by alkaline deposition. The results of chemical analyses of snow were converted to mean monthly depositions using the water equivalent of snow and the time of deposition. Deposition of SO₄ during 1985–1993 was 32% lower compared with the period 1976–1984, which presumably results from 70% reduction of sulphur emissions in Finland since the beginning of the 1980s. The deposition level of NO₃-N seemed to stay relatively stable during the whole 18 year period while the deposition of NH₄-N has decreased 18%.     

Unsaturated zone pore water chemistry and the edge effect in a beech forest in Southern England

Twenty one pore water chemistry profiles were obtained for a range of inorganic solutes from the Chalk unsaturated zone in or adjacent to Black Wood, a 2.4 kM² mature beech wood in southern England. The depth sampled was normally 10 m, but some boreholes were shallower and one was deeper (30 m). Towards the centre of the wood, average pore water concentrations were: Cl (17–25 mg l^-1), SO₄ (20–40 mg l^-1) and NO₃-N (5–10 mg 1^-1). In small clearings within the wood, concentrations of Cl (12–20 mg l^-1) and SO₄ (27–36 mg 1^-1) were somewhat lower but the average concentration of nitrate-N was higher (16 mg 1^-1). Pore water chloride and nitrate concentrations under a small area of ash were lower than under the beech. There was a significant increase in the concentration of a number of solutes, especially Cl, Na, Mg and SO₄, close to the exposed western edge of Black Wood. This ‘edge effect’ decreased exponentially with a half distance of about 9 m. The effect was less consistent at the more sheltered eastern edge. Average pore water concentrations of up to 310 mg 1^-1 Cl and 312 mg 1^-1 SO₄ were found at the western edge. Paradoxically, close to the western edge pore water nitrate concentrations were often very low, frequently less than 1 mg 1^-1 NO₃-N. Using the parameters derived from a simple exponential model of the Black Wood data, calculations suggested that the edge effect would lead to significantly enhanced Cl and SO₄ pore water concentrations in forests of a few hectares, a size typical of many of those currently being planted. The consistently lower moisture content of the Chalk close to the forest edges suggested that groundwater recharge may have been lower there.     

植被缓冲带对乌梁素海区域农业面源污染的削减效果

通过在内蒙古乌拉特前旗乌梁素海九排干岸边构建湖滨植被缓冲带,研究不同盐生植物种类和配置对农业面源污染削减效果的影响。结果表明:无植物空白对照带对径流和渗流水中TN、TP和COD无明显削减规律,芦苇、碱蓬、柽柳和芦苇—碱蓬混播缓冲带随着缓冲带宽度的增加削减率呈先增加后减缓的趋势,渗流水中污染物质的削减效果优于径流水。其中,芦苇对径流和渗流水中TN、TP的削减效果最好,削减率分别为53.56%,79.17%和62.37%,83.25%;碱蓬对径流和渗流水中COD的削减效果最好,削减率分别为50.53%,67.34%。通过计算得到4种植被缓冲带的最佳宽度为19~29 m,其中,碱蓬缓冲带宽度为19 m。综合考虑,可以选择真盐生植物碱蓬作为乌梁素海盐渍化湖滨带植被重建的首选植物,并将植被缓冲带在该地区扩展研究,推广应用。     

Spatial occurrence and geochemistry of soil salinity in Datong basin,northern China

Purpose

Soil quality assessment is tremendously important for agronomic and environmental concern. The objective of this study was to spatially evaluate soil salinity and its geochemistry at regional scale.

Materials and methods

A soil quality assessment study was conducted over a 1,000 km² field in Datong basin, northern China via collecting and determining 163 topsoil samples. A combined approach of statistical methods and hydrochemical tools was applied for a comprehensive analysis in this study.

Results and discussion

In the study area, the nonsaline lands (total dissolved solids (TDS) <0.08 %, Ca-HCO₃ type soils) that are located in the pluvial plains consist of coarse-medium sands and deep unsaturated zone (depth >10 m). The slightly (0.08 %?<?TDS?<?0.2 %, Ca-Na-HCO₃-NO₃ type soils) and the moderately (0.2 %?<?TDS?<?1 %, Ca-Na-SO₄ type soils) saline lands are located in the alluvial plains and the central basin composed of fine sediments like fine sands, loams and silts, and intermediately deep unsaturated zone (depth 2–10 m). By contrast, due to irrigation, the very (1 %?<?TDS?<?2 %) and the extremely (TDS >2 %) saline areas with Na-SO₄/Na-Cl type soils are locally found in some desolate lands comprised of silty clays and shallow unsaturated zone (depth <2 m) in the central basin.

Conclusions

As a result of water-rock/sediments interactions, effects of landscapes and anthropogenic activities, soil salinity is characterized by strong spatial variability in Datong. The new insights into the basin-scale distribution pattern of soil salinity in inland basins of silicate terrain under arid climatic conditions should be applicable in other similar regions of the world.     

NEEDLE S FRACTIONS AND S TO N RATIOS AS INDICES OF SO2 DEPOSITION

Needles of Scots pine (Pinus sylvestris L.) from 25 and 40 sampling plots in southern and northern Finland, respectively, that had earlier been analysed for total sulphur concentration (S_t) were reanalysed for foliar sulphate sulphur (SO₄–S) and total nitrogen (N_t). Organic sulphur content (S_o) was calculated as the difference between S_t and SO₄–S. Current (c) and previous-year (c+1) needles were collected from southern Finland in December 1989 and c – c+2 needles from northern Finland in September-October 1990/September 1992. The results show that the S_t concentration and S_t/N_t ratio in Scots pine needles are good indices of dry deposition of SO₂ in general, while SO₄–S concentrations and SO₄–S/S_o ratios can be used in areas with low N supply from the soil and/or low wet deposition of N. The normal S_t concentration in needles of Scots pines growing on a podzol with low N supply is considered to be 500–700 μg g^-1 and that of SO₄–S 100–200 μg g^-1. An increase of 100 μg g^-1 in needle S_t may be attributed to a rise of 1.4 μg m^-3 in ambient SO₂ concentration in areas with relatively low SO₂ concentrations (>15 μg m^-3). A critical level of 5 μg m^-3 as an annual and growing season mean is proposed for forestry in northern Europe (north of 60°N).     

Sources of sulphate and acidity in wetlands and lakes in Nova Scotia

There is a declining gradient of wet SO₄ deposition from south to north in Nova Scotia with the highest values being in the south, along with a localized increase around the Halifax metropolitan area, due to local SO₄ emission. Edaphic conditions such as drainage from soils containing gypsum or drainage on disturbed rocks containing pyrite, provide additional SO₄ to surface waters.Acidity is usually absent in the former (pH > 7.0) and very high in the latter (as low as pH 3.6). By contrast peaty, organic drainages release water low in SO₄ during the growing season but they release high amounts of organic anions (A?), consequently, these waters maintain decreased pH values, usually < 4.5. A study of over 80 wetlands and lakes during the ice free period in Nova Scotia showed that sea salt corrected SO₄ concentrations range from 45 ueq L^?1 in the south end of the province, ～30 ueq L^?1 in the Kejimkujik area and < 17 ueq L^?1 in the northern areas with values > 85 ueq L^?1 in the Halifax area, reflecting the atmospheric deposition pattern of SO₄ The SO₄ concentrations may be > 2000 ueq L^?1 in drainages containing gypsum, > 700 ueq L^?1 in drainages over pyrite bearing socks but < 20 ueq/L^?1 in streams draining bogs. The SO₄ concentrations change considerably during the non-growing season when the ground is saturated with water or frozen, and the runoff is high (snow and rain often alternate in winter). Under such conditions SO₄ concentration drops in the two former cases and increases in bog drainages, accompanied with a considerable drop in (A?) concentrations. Care should be taken when interpreting SO₄ concentrations in surface waters in Nova Scotia with respect to atmospheric SO₄ deposition.     

Solute transfer from drained fen peat

The relationship between peat hydrophysical properties and solute transfer to drainage ditches was examined for a pump-drained soligenous valley fen in SW England. Drainage increased the bulk density and lowered the hydraulic conductivity of the peat, to the extent that, water table drawdown could not be detected beyond 5 m from the drainage ditch or field drains. The water table drawdown zone acted as the source of solutes transfered to the drainage ditch on pumping. A distinct solute release sequence was recorded in the drainage ditch, with SO₄-S peaking before NH₄-N, which was followed by Ca, Mg and NO₃-N. Ca and Mg release was delayed by up two days following a pump event. Solute concentrations in pump-drained ditches were significantly higher than those of drainage channels unaffected by pumping. Solute transfer from the peat as a result of pump drainage, has resulted in water quality deterioration within the peatland.     

Phosphate sorption in allophanic soils and release of sulphate, silicate and hydroxyl

Phosphate (P) sorption and the concomitant release of sulphate (SO,), silicate (Si) and hydroxyl ion (OH) were determined on three allophanic soils from Spain, at different P concentrations. P effectively replaced SO₄, Si and OH. However, at every stage of P sorption, the molar ratios of the total amounts of anions released (SO₄+ Si + OH) to that of the sorbed P were low. The amount of added P affected the relative proportions of SO₄, Si and OH exchanged. At low concentrations of P, phosphate sorption was accompanied mostly by release of the adsorbed SO₄ with some Si. As more P was sorbed an increasing displacement of OH was also observed.     

稻田—田埂过渡区土壤水分运动与保持特征

为揭示田埂对稻田水分渗漏的影响,以江汉平原典型稻田—田埂过渡区为研究对象,采用室内土壤理化性质分析、水力学参数测定和田间染色示踪等方法量化了过渡区各位点(田内、田埂和灌溉沟)土壤剖面导水与持水性能差异,并揭示了该区域的水流特征。结果表明:(1)不同位点的土壤饱和导水率(Ks)均随土层深度的增加而减小,上层(-20—35cm)高于中、下层(35—65cm),剖面导水性能表现为田埂灌溉沟田内,田埂平均Ks分别是灌溉沟和田内的1.6倍和16.0倍;(2)同一吸力值下不同位点土壤含水量差异较大,田内含水量最高,灌溉沟其次,田埂最低,在持水性能上表现为田内灌溉沟田埂;(3)田埂土壤受动物活动和根系生长影响剧烈,导致其大孔隙(当量孔径0.3mm)含量整体上高于田内,在染色特征上表现为田埂中、下层土壤染色面积显著高于田内。由于稻田-田埂过渡区不同位点土壤的导水和持水能力差异显著,稻田水分不仅可以在田内发生垂直渗漏,还可以通过田埂区域垂直入渗和跨田埂侧流两种方式快速流失,进而加速了稻田水分的散失。     

Solute adjustment to salinity and calcium supply in cultivated and wild barley

Ion relations, water content, leaf water potential, and osmotic adjustment were determined for cultivated barley (cv Harrington) and wild barley grown under mixed sulphate (SO₄) salts with varied calcium (Ca) supply using a hydroponic system. Salinity induced significant increases of leaf, stem and root sodium (Na) concentrations in both species. Salt‐stressed wild barley roots accumulated more Na than shoots, and transport of Na from roots to shoots was low compared to Harrington. Cultivated barley had lower Ca concentrations than wild barley, especially in the low Ca salt treatment. Although potassium (K/Na) and Ca/Na ratios were higher in control wild barley plants than in Harrington, they declined under salt stress, irrespective of Ca supply. Major osmotica in wild barley leaves were K, sugars, organic acids, and quaternary ammonium compounds, while in Harrington they were cations, including Na, K and Mg, and anions such as phosphate (PO₄) and SO₄. Wild barley maintained better water status than Harrington under low Ca salt treatment. Supplemental Ca improved water status more in Harrington than in wild barley. Lack of osmotic adjustment to salinity in wild barley apparently resulted from its ion exclusion. Low Ca salt treatment caused Ca deficiency, Na toxicity, and loss of turgor in Harrington. In the high Ca salt treatment, Harrington had improved water and ion relations, as well as positive turgor.     

Geographic origin of Pinus sylvestris populations influences the effects of air pollution on flowering and growth

Flowering and height growth of 20 Scots pine (Pinus sylvestris L.) populations from 10 countries were analyzed at two replicated provenance sites established in 1984 in western Poland. One site was 2 km from a phosphate fertilizer factory that emits SO₂ and fluorides, and the other 12 km to the southeast in an area free of acute air pollution levels was treated as a control. Slow-growing populations from the southern (40 to 45°N) and northern (58 to 61°N) part of the species range exhibited relatively smaller air pollutioninduced growth reductions than those from the central part of the range (45 to 58°N). Trees growing in the control area started flowering 4 yrs earlier than those at the polluted site. The percent of trees flowering at the control site differed significantly among provenances in both 1988 and 1990. The mean percent of trees with flowers was three times lower at the polluted site. The least sensitive southern and northern provenances in terms of pollutioninduced reductions in growth exhibited the largest pollution-induced decreases in flowering. These findings indicate that the sensitivity of vegetative organs to air pollution stress is not always paralleled by the sensitivity of reproductive organs.     

recent lake acidification and recovery trends in southern quebec,canada

A total of 51 lakes in southern Quebec, Canada, were sampled between 1985 and 1993 to study changes in water chemistry following reductions in SO₂ emissions (main precursor of acid precipitation). Time series analysis of precipitation chemistry revealed significant reductions in concentrations and deposition of SO₄ ^2- from 1981 to 1992 in southern Quebec as well as reductions in concentrations and deposition of base cations (Ca²⁺, Mg²⁺), NO₃ ^- and H⁺ in the western section of the study area. Reductions in atmospheric inputs of SO₄ ^2- have resulted in decreased lakewater SO₄ ^2- concentrations in the majority of the lakes in our study, although only a small fraction (9 of 37 lakes used in the temporal analysis) have improved significantly in terms of acidity status (pH, acid neutralizing capacity – ANC). The main response of the lakes to decreased SO₄ ^2- is a decrease in base cations (Ca²⁺+Mg²⁺), which was observed in 17 of 37 lakes. Seventeen lakes also showed significant increases in dissolved organic carbon (DOC) over the period of study. The resulting increases in organic acidity as well as the decrease in base cations could both play a role in delaying the recovery of our lakes.     

Differential leaching of cations and sulfate in gypsum amended soils

Abstract

An adequate supply of available Ca in the soil solution of the pegging zone during fruit development is required for production of high yields of high quality peanuts (Arachis hypogaea L.). On low Ca soils, application of gypsum during early bloom is recommended in order to ascertain adequate availability of Ca. Reaction of gypsum in soils under leaching conditions vary considerably and play an important role in fruit development and yield of peanuts. A laboratory study was conducted in leaching soil columns to investigate the effects of one gypsum amendment on leaching of Ca, K, Mg, and SO₄ to a depth of 8 cm (fruiting zone of peanut). Six soils of varying physical and chemical properties representative of major peanut growing soils in Georgia were utilized. Following leaching with 15 cm water through gypsum‐amended soil columns, 50% to 56% and 74% to 77% of applied Ca and SO₄, respectively, were leached below 8 cm in the sandy‐Carnegie, Dothan, Fuquay and Tifton soils. The respective values for the sandy clay loam‐Greenville and Faceville soils were 28% to 36% and 58% to 69%. Lower initial Ca status and greater leaching of Ca from the applied gypsum in the sandy soils as compared to sandy clay loam soils suggest greater beneficial effects of supplemental gypsum application for peanut production in the former soils than in the latter soils. Leaching of K or Mg (as percentage of Mehlich 1 extractable K or Mg) in gypsum‐amended treatment was considerably greater in sandy soils than that in the sandy clay loam soils. In view of the reported adverse effects of high concentrations of soil K and Mg in the fruiting zone on the yield and quality of peanuts, greater leaching of K and Mg from the fruiting zone in gypsum amended sandy soils enable them to maintain a favorable cation balance for the production of high yields of quality peanuts.