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1.
Omar Ali Al-Khashman 《The Environmentalist》2008,28(3):203-215
The present study investigates the physical, chemical, and biological characteristics of spring water samples in Shoubak area
in the southern Jordan. The samples were collected from May 2004 to May 2005. All samples were analyzed for temperature, conductivity,
dissolved oxygen, pH, major cations (Ca2+, Mg2+, K+, Na+), major anions (Cl−, NO3−, HCO3−, SO42−, PO43−, F−), and trace metals (Fe2+, Al3+, Mn2+, Cu2+, Cr3+, Ni2+, Zn2+, Pb2+, Cd2+). Water quality for available springs showed high salinity through long period of contact with rocks. The ion concentrations
in the water samples were from dissolution of carbonate rocks and ion exchange processes in clay. The general chemistry of
water samples was typically of alkaline earth waters with prevailing bicarbonate chloride. Some springs showed elevated nitrate
and sulfate contents which could reflect to percolation from septic tanks, cesspools, and agricultural practices. The infiltration
of wastewater from cesspools and septic tanks into groundwater is considered the major source of water pollution. The results
showed that there were great variations among the analyzed samples with respect to their physical, chemical and biological
parameters, which lie below the maximum permissible levels of the Jordanian and WHO drinking water standards. The results
indicate that the trace metals of spring’s water of Shoubak area do not generally pose any health or environmental problems.
Factor analysis was used to identify the contributers to water quality. The first factor represents major contribution from
anthropogenic activities, while the second one represents major contribution from natural processes. 相似文献
2.
Inter-seasonal studies on the trace metal load of surface water, sediment and Tympanotonus fuscatus var. radula of Iko River were conducted between 2003 and 2004. The impact of anthropogenic activities especially industrial effluent,
petroleum related wastes, gas flare and episodic oil spills on the ecosystem are remarkable. Trace metals analyzed included
cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), vanadium (V) and zinc (Zn). Sediment
particle size analysis revealed that they were characteristically psammitic and were predominantly of medium to fine grained
sand (>73%), less of silt (<15%) and clay (<10%). These results correlated with low levels of trace elements such as Pb (0.03 ± 0.02 mg kg−1), Cr (0.22 ± 0.12 mg kg−1), Cd (0.05 ± 0.03 mg kg−1), Cu (0.04 ± 0.02 mg kg−1) and Mn (0.23 ± 0.22 mg kg−1) in the sediment samples. This observation is consistent with the scarcity of clayey materials known to be good scavengers
for metallic and organic contaminants. Sediments indicated enhanced concentration of Fe, Ni and V, while other metal levels
were relatively low. The concentrations of all the metals except Pb in surface water were within the permissible levels, suggesting
that the petroleum contaminants had minimal effect on the state of pollution by trace metals in Iko River. Notably, the pollutant
concentrations in the sediments were markedly higher than the corresponding concentrations in surface water and T. fuscatus tissues, and decreased with distance from point sources of pollution. 相似文献
3.
Zambrano L Contreras V Mazari-Hiriart M Zarco-Arista AE 《Environmental management》2009,43(2):249-263
Awareness of environmental heterogeneity in ecosystems is critical for management and conservation. We used the Xochimilco
freshwater system to describe the relationship between heterogeneity and human activities. This tropical aquatic ecosystem
south of Mexico City is comprised of a network of interconnected canals and lakes that are influenced by agricultural and
urban activities. Environmental heterogeneity was characterized by spatially extensive surveys within four regions of Xochimilco
during rainy and dry seasons over 2 years. These surveys revealed a heterogeneous system that was shallow (1.1 m, SD = 0.4 ),
warm (17°C, SD = 2.9), well oxygenated (5.0 mg l−1, SD = 3), turbid (45.7 NTU SD = 26.96), and extremely nutrient-rich (NO3–N = 15.9 mg l−1, SD=13.7; NH4–N = 2.88 mg l−1, SD = 4.24; and PO4–P = 8.3 mg l−1, SD = 2.4). Most of the variables were not significantly different between years, but did differ between seasons, suggesting
a dynamic system within a span of a year but with a high resilience over longer periods of time. Maps were produced using
interpolations to describe distributions of all variables. There was no correlation between individual variables and land
use. Consequently, we searched for relationships using all variables together by generating a combined water quality index.
Significant differences in the index were apparent among the four regions. Index values also differed within individual region
and individual water bodies (e.g., within canals), indicating that Xochimilco has high local heterogeneity. Using this index
on a map helped to relate water quality to human activities and provides a simple and clear tool for managers and policymakers. 相似文献
4.
The concern related to the drinking of reverse osmosis (RO) water containing low levels of minerals is growing day by day. This study involves the analysis of water samples from various drinking water sources in a rural site, Mirchpur village, an Indus Valley civilization site (grid location: 29° 18′ 42.3″ N, 76° 10′ 33.0″ E) of Hisar, India, along with the health survey of human subjects. The hydrochemistry of water collected from hand pumps, river canals, tube wells, submersibles, and the RO systems installed in various homes was explored for pH, EC, TH, TDS, turbidity, cations (Na+, Ca2+, Mg2+), anions (CO32−, HCO3−, Cl−, SO42−, NO3−, F−), and elements (Fe, Pb, Se) employing the ion chromatography, flame photometry, and ICP-AES techniques. Lead (Pb) and Selenium (Se) were detected in trace amounts (0.30–2.6 μg L−1; 0.10–4.1 μg L−1, respectively) in all the samples, including the samples collected from RO purifiers, but Iron (Fe) was not detected in RO samples even in trace amounts. The F-levels in hand pump water (HPW) and submersible water (SW) (1.9 and 1.7 mg L−1, respectively) and TDS levels in SW (3048 mg L−1) were found to be above WHO and BIS safe limits. TDS levels in the river canal (900 mg L−1), tube well (1104 mg L−1), hand pump (1170 mg L−1), and submersible samples (3048 mg L−1) were found significantly higher as compared to the RO personal water (ROPW; 216 mg L−1) and RO supply water (ROSW; 90 mg L−1). The collected epidemiological data reveals that 21%, 19%, 13%, and 12% of natives reported skin, kidney, hair fall, liver, and stomach issues, respectively, suspecting the crucial role of high TDS and fluoride levels in the area. This study also provides a comparison between the quality of RO and the direct supply water, along with correlation matrices for different parameters, which gives a rationale for the limitations of drinking direct supply water without any purification and RO water containing low mineral content. 相似文献
5.
Suburban Areas in Developing Countries and Their Relationship to Groundwater Pollution: A Case Study of Mar del Plata, Argentina 总被引:1,自引:0,他引:1
Hector E. Massone Daniel E. Martinez Jose L. Cionchi Emilia Bocanegra 《Environmental management》1998,22(2):245-254
2 were sampled in order to verify the impact of these problems on groundwater. All samples were analyzed for major ions, and
about 30 of them for fecal coliforms and heavy metals. Nineteen samples were selected for pesticide analyses. The average
nitrate content was 80 mg/liter, eight times the regional background value. Fecal coliforms were detected in 60% of the analyzed
samples. Zinc content and a high Cl−/HCO3
− ratio were observed in the surroundings of the solid waste disposal area. Moreover, lindane and heptachlor pesticides were
detected in ten samples. 相似文献
6.
Ensemble of corrosion indices was combined to study the corrosion tendency of the drinking water supply at the University
of Benin, Nigeria. The experimental results were analysed in terms of three corrosion indices-Langelier Index, Ryznar Index
and Larson–Skold Index. According to the evaluation, the Langelier Index ranged from −5.569 to −3.684, Ryznar Index was between
13.340 and 16.418 while the Larson–Skold Index was between 1.191 and 31.750. Results indicated that the water may be corrosive.
A regression of these indices on iron concentration (ppm) showed that Langelier Index, Ryznar Index and Larson–Skold Index
have R
2 of 0.5868, 0.6577 and 0.7063, respectively. The positive correlation between iron levels and the corrosion indices suggested
that iron levels were directly related to increase in corrosion tendency. 相似文献
7.
Surendra Suthar 《The Environmentalist》2008,28(2):76-84
The potential of the epigeic earthworm Eisenia fetida to stabilize sludge␣(generated from a distillation unit of the sugar industry) mixed with cow dung, in different proportions
i.e. 20% (T1), 40% (T2), 60% (T3) and 80% (T4) has been studied under laboratory conditions for 90 days. The␣ready vermicompost was evaluated for its’ different physico-chemical
parameters using standard methods. At the end of experiment, all vermibeds expressed a significant decrease in pH (7.8–19.2%)
organic C (8.5–25.8%) content, and an increase in total N (130.4–170.7%), available P (22.2–120.8%), exchangeable K (104.9–159.5%),
exchangeable Ca (49.1–118.1%), and exchangeable Mg (13.6–51.2%) content. Overall, earthworms could maximize decomposition
and mineralization efficiency in bedding with lower proportions of distillery sludge. DTPA extractable metal reduction in
substrate was recorded between the ranges of 12.5–38.8% for Zn, 5.9–30.4% for Fe, 4.7–38.2% for Mn and 4.5–42.1% for Cu. Maximum
values for the mean individual live weight (809.69 ± 20.09 mg) and maximum individual growth rate (mg wt. worm−1 day−1) (5.81 ± 0.18) of earthworms was noted in T1 treatment, whereas cocoon numbers (69.0 ± 7.94) and individual reproduction rate (cocoon worm−1 day−1) (0.046 ± 0.002) was highest in T2 treatment. Earthworm mortality tended to increase with increasing proportion of distillery sludge, and maximum mortality
in E. fetida was recorded for the T4 (45.0 ± 5.0) treatment. Results indicate that vermicomposting might be useful for managing the energy and nutrient rich distillery
sludge on a low-input basis. Products of this process can be used for sustainable land restoration practices. The feasibility
of worms to mitigate the toxicity of metals also reduces the possibility of soil contamination, which has been reported in
earlier studies during direct field application of industrial wastes. 相似文献
8.
Evaluation of groundwater and soil pollution in a landfill area using electrical resistivity imaging survey 总被引:8,自引:0,他引:8
Landfills are sources of groundwater and soil pollution due to the production of leachate and its migration through refuse.
This study was conducted in order to determine the extent of groundwater and soil pollution within and around the landfill
of Seri Petaling located in the State of Selangor, Malaysia. The condition of nearby surface water was also determined. An
electrical resistivity imaging survey was used to investigate the leachate production within the landfill. Groundwater geochemistry
was carried out and chemical analysis of water samples was conducted upstream and downstream of the landfill. Surface water
was also analyzed in order to determine its quality.
Soil chemical analysis was performed on soil samples taken from different locations within and around the landfill in the
vadose zone (unsaturated zone) and below the water table (in the soil saturated zone). The resistivity image along line L–L1 indicated the presence of large zones of decomposed waste bodies saturated with highly conducting leachate. Analysis of trace
elements indicated their presence in very low concentrations and did not reflect any sign of heavy metal pollution of ground
and surface water or of soil.
Major ions represented by Na, K, and Cl were found in anomalous concentrations in the groundwater of the downstream bore hole,
where they are 99.1%, 99.2%, and 99.4%, respectively, higher compared to the upstream bore hole. Electrical conductivity (EC)
was also found in anomalous concentration downstream. Ca and Mg ions represent the water hardness (which is comparatively
high downstream). There is a general trend of pollution towards the downstream area. Sulfates (SO4) and nitrates (NO3) are found in the area in low concentrations, even below the WHO standards for drinking water, but are significantly higher
in the surface water compared to the groundwater. Phosphate (PO4) and nitrite (NO2), although present in low levels, are significantly higher at the downstream. There is no significant difference in the amount
of fluoride (F) in the different locations. In the soil vadose zone, heavy metals were found to be in their typical normal
ranges and within the background concentrations. Soil exchangeable bases were significantly higher in the soil saturated zone
compared to the vadose zone, and no significant difference was obtained in the levels of inorganic pollutants. With the exception
of Cd, the concentration ranges of all trace elements (Cu, Zn, Cr, Pb, and Ni) of Seri Petaling landfill soils were below
the upper limits of baseline concentrations published from different sources. 相似文献
9.
Adolfo Campos C. 《Environmental management》2010,46(2):213-224
This study addressed the effects of land use and slope position on soil inorganic nitrogen and was conducted in small watersheds.
The study covered three land use types: tropical cloud forest, grassland, and coffee crop. To conduct this research, typical
slope small watersheds were chosen in each land use type. Slopes were divided into three positions: shoulder, backslope, and
footslope. At the center of each slope position, soil sampling was carried out. Soil inorganic nitrogen was measured monthly
during a period of 14 months (July 2005–August 2006) with 11 observations. Significant differences in soil NH4
+–N and NO3
−–N content were detected for both land use and sampling date effects, as well as for interactions. A significant slope position-by-sampling
date interaction was found only in coffee crop for NO3
−–N content. In tropical cloud forest and grassland, high soil NH4
+–N and low NO3
−–N content were recorded, while soil NO3
−–N content was high in coffee crop. Low NO3
−–N contents could mean a substantial microbial assimilation of NO3
−–N, constituting an important mechanism for nitrogen retention. Across the entire land use set, the relationship between soil
temperature and soil inorganic N concentration was described by an exponential decay function (N = 33 + 2459exp−0.23T, R
2 = 0.44, P < 0.0001). This study also showed that together, soil temperature and gravimetric soil water content explained more variation
in soil inorganic N concentration than gravimetric soil water content alone. 相似文献
10.
The impact of anthropogenic activities on the fluctuation of nutrients along the Densu River and its tributaries was studied.
High concentrations of nutrients were observed in the study area but the river was found to be circumneutral and fresh with
pH ranging between 6.54 and 7.84. The levels of NH4
+–N ranged between 0.21 and 2.1 mg L−1 with mean concentration of 1.19 ± 0.02 mg L−1 while that of nitrate is between 0.13 and 5.21 mg L−1 with a mean concentration of 2.07 ± 0.01 mg L−1. The levels of PO4
3−–P fluctuated within the range 0.54 and 1.04 mg L−1 with a mean of 0.84 ± 0.01 mg L−1. The Densu River Basin was also found to be with organic matter with depleted dissolved oxygen. The river recorded high BOD
values ranging from 6.91 to 18.8 mg L−1. Concentration of nutrients and organic pollutants increased as a consequence of anthropogenic inputs particularly from domestic,
agricultural and municipal sources. The highly impaired sites were those located close to the urbanized, agricultural and
high-density residential areas. The relatively high concentration of nitrate and phosphate in the river indicated that it
was quite eutrophic. 相似文献
11.
Soil-erosion and runoff prevention by plant covers in a mountainous area (se spain): Implications for sustainable agriculture 总被引:1,自引:0,他引:1
V. H. Durán Zuazo J. R. Francia Martínez C. R. Rodríguez Pleguezuelo A. Martínez Raya B. Carcéles Rodríguez 《The Environmentalist》2006,26(4):309-319
In the Mediterranean region the intensities and amounts of soil loss and runoff on sloping land are governed by rainfall pattern
and vegetation cover. Over a two-year period (1998–1999), six wild species of aromatic and mellipherous plants (Thymus serpylloides subsp. Gadorensis, Thymus baeticus Boiss, Salvia lavandulifolia Vahl., Santolina rosmarinifolia L., Lavandula stoechas L. and Genista umbellata Poiret) were selected for erosion plots to determine their effectiveness in reducing water erosion on hillslopes of the Sierra
Nevada Mountain (SE Spain). The erosion plots (including a bare-soil plot as control), located at 1,345 m in altitude, were
2 m2 (2 m × 1 m) in area and had 13% incline. The lowest runoff and soil erosion rates, ranging from 9 to 26 mm yr−1 and from 0.01 to 0.31 Mg ha−1 yr−1, respectively, over the entire study period, were measured under the Thymus serpylloides. Lavandula stoechas L. registered the highest rates among the plant covers tested, runoff ranging from 77 to 127 mm yr−1 and erosion from 1.67 to 3.50 Mg ha−1 yr−1. In the bare-soil plot, runoff ranged from 154 to 210 mm yr−1 and erosion from 4.45 to 7.82 Mg ha−1 yr−1. According to the results, the lowest-growing plant covers (Thymus serpylloides and Salvia lavandulifolia Vahl.) discouraged the soil erosion and runoff more effectively than did the taller and open medium-sized shrubs (Santolina rosmarinifolia L., Genista umbellata Poiret, Thymus baeticus Boiss and Lavandula stoechas L.). Monitoring allowed more direct linkage to be made between plant covers and the prevention of erosion, with implications
for sustainable mountain agriculture and environmental protection. 相似文献
12.
Spatial Variability of Groundwater Depth and Quality Parameters in the National Capital Territory of Delhi 总被引:3,自引:0,他引:3
The groundwater quantity and quality scenario is of much concern in the National Capital Territory of Delhi, India, which
necessitates an investigation to envisage the extent of spatial variability of groundwater depth and pollutant concentration
levels in this region. Therefore, in this study, an effort was made to generate the spatial variability map of groundwater
depth and quality parameters (viz. chloride, electrical conductivity, fluoride, magnesium, and nitrate). Ordinary kriging
was used to analyze the spatial variability of groundwater depth and quality parameters, whereas indicator kriging was used
to analyze groundwater quality parameters equal to or greater than the pollution threshold values. It was observed that the
semivariogram parameters fitted well in the exponential model for water depth and in the spherical model for water quality
parameters. The generated spatial variability maps indicated that in 43% of the study area, groundwater depth was within 20 m.
The salinity level was higher than 2.5 dS m−1 in 69% of the study area and the nitrate concentration exceeded 45 mg l−1 in 36% of the area. The probability maps showed that about 24% of the area had the highest probability (0.8–1.0) of exceedence
of the threshold electrical conductivity value and an area of 2% exhibited the highest probability of exceedence of the threshold
value of nitrate concentration in the groundwater. The generated spatial variability and probability maps will assist water
resource managers and policymakers in development of guidelines in judicious management of groundwater resources for agricultural
and drinking purposes in the study area. 相似文献
13.
Surendra Suthar 《The Environmentalist》2007,27(3):329-335
Efforts have been made to convert the guar gum industrial waste into a value-added product, by employing a new earthworm species
for vermicomposting e.g. Perionyx sansibaricus (Perrier) (Megascolecidae), under laboratory conditions. Industrial lignocellulosic waste was amended with other organic
supplements (saw dust and cow dung); and three types of vermibeds were prepared: guar gum industrial waste + cow dung + saw
dust in 40: 30: 30 ratio (T1), guar gum industrial waste + cow dung + saw dust in 60: 20: 20 ratio (T2,), and guar gum industrial waste + cow dung + saw dust in 75: 15: 10 ratio (T3). As compared to initial concentrations, vermicomposts exhibited a decrease in organic C content (5.0–11.3%) and C:N ratio
(11.1–24.4%) and an increase in total N (18.4–22.8%), available P (39.7–92.4%), and exchangeable K (9.4–19.7%) contents, after
150 days of vermicomposting. A vermicomposting coefficient (VC) was used to compare of vermicomposting with the experimental control (composting). P. sansibaricus exhibited maximum value of mean individual live weight (742.8 ± 21.1 mg), biomass gain (442.94 ± 21.8 mg), growth rate (2.95 ± 0.15 mg
day−1), cocoon numbers (96.0 ± 5.1) and reproduction rate (cocoons worm−1 day−1) (0.034 ± 0.001) in T2 treatment. In T3 maximum mortality (30.0 ± 4.01 %) in earthworm population was observed. Overall, T2 vermibed appeared as an ideal substrate to manage guar gum industrial waste effectively. Vermicomposting can be proposed
as a low-input basis technology to convert industrial waste into value-added biofertilizer. 相似文献
14.
Nine heavy metals were estimated in lichen, Phaeophyscia hispidula (Ach.) Moberg, collected from 12 different sites of Dehradun, capital city, to analyze the air quality of Uttarakhand. Total
metal concentration was the highest at Mohkampur Railway Crossing, Hardwar Road (42,505 μg g−1). Dela Ram Chowk, located in the center of the city, also had higher metal concentration, 34,317 μg g−1, with maximum concentration of Pb at 12,433 μg g−1, while Nalapani forest area had minimum total metal concentration (1,873 μg g−1) as well as minimum Pb level at 66.6 μg g−1, indicating anthropogenic activity, mainly vehicular activity, responsible for the increase in metal concentration in the
ambient environment. In comparison with the earlier years 2004 and 2006, air pollution as indicated by similar lichen shows
a considerable increase in the total metal concentration (especially Pb) in the ambient air of Dehradun city, which may be
attributed to exponential rise in the traffic activity in the last 5 years. 相似文献
15.
The distribution of some heavy metals, namely Cd, Pb, Zn, Fe, Cu, Cr and Mn in epipellic sediments of Igbede, Ojo and Ojora
rivers of Lagos was studied weekly in the early summer (November) of 2003. The levels of selected trace metals were determined
using Atomic Absorption Spectrophotometer (UNICAM 969 AAS SOLAR). Trends in heavy metal burdens in the sediments revealed
weekly variations in all the rivers assessed. Statistical analyses also showed different mean levels of trace metals in the
aquatic environments, the distribution of which followed the sequence Fe > Zn > Mn > Pb > Cu > Cr > Cd, Fe > Zn > Cu > Mn
> Pb > Cr > Cd and Fe > Zn > Mn > Cu > Cr > Pb > Cd in Igbede, Ojo and Ojora rivers respectively. Fe recorded the highest
concentration levels (1,582.95 ± 96.57 μ g/g–1,910.34 ± 723.19 μ g/g) in all the sediments investigated while the Cd levels
(0.06 ± 0.10 μ g/g–0.47 ± 0.36 μ g/g) were the lowest. Expectedly, trace metal concentrations in fine grain muddy sediments
of the Igbede and Ojo coastline were much higher than those of Ojora which consist of coarse and sandy deposits covering the
near shore area. Generally, the results obtained fell within tolerable limits stipulated by World Health Organization (WHO). 相似文献
16.
Here we report N2O emission results for freshwater marshes isolated from human activities at the Sanjiang Experimental Station of Marsh Wetland
Ecology in northeastern China. These results are important for us to understand N2O emission in natural processes in undisturbed freshwater marsh. Two adjacent plots of Deyeuxia angustifolia freshwater marsh with different water regimes, i.e., seasonally waterlogged (SW) and not- waterlogged (NW), were chosen for
gas sampling, and soil and biomass studies. Emissions of N2O from NW plots were obviously higher than from the SW plots. Daily maximum N2O flux was observed at 13 o′clock and the seasonal maximum occurred in end July to early August. The annual average N2O emissions from the NW marsh were 4.45 μg m−2 h−1 in 2002 and 6.85 μg m−2 h−1 in 2003 during growing season. The SW marsh was overall a sink for N2O with corresponding annual emissions of −1.00 μg m−2 h−1 for 2002 and −0.76 μg m−2 h−1 for 2003. There were significant correlations between N2O fluxes and temperatures of both air and 5-cm-depth soil. The range of soil redox potential 200–400 mV appeared to be optimum
for N2O flux. Besides temperature and plant biomass, the freeze–thaw process is also an important factor for N2O emission burst. Our results show that the freshwater marsh isolated from human activity in northeastern China is not a major
source of N2O. 相似文献
17.
The photosensitizing perylenequinone toxin elsinochrome A (EA) is produced in culture by the bindweed biocontrol fungus Stagonospora convolvuli LA39 where it apparently plays a pathogenicity related role. We investigated the fate of EA with reference to its stability
under different temperature and light conditions. EA remained stable when boiled in water at 100∘C for 2 h. Similarly, exposing EA to 3–27∘C in the dark for up to 16 weeks did not affect its stability either in dry or in aqueous form. However, results from irradiation
experiments indicate that direct photolysis may be a significant degradation pathway for EA in the environment. EA either
in dry form or dissolved in water was degraded by different irradiation wavelengths and intensities, with degradation plots
fitting a first order rate kinetics. EA degraded faster if exposed in aqueous form, and at higher quantum flux density (μmol
s−1 m−2). Sunlight was more effective in degrading EA than artificial white light and ultraviolet radiations (UV-A or UV-B). Exposing
EA to natural sunlight, particularly, during the intense sunshine (1,420– 1,640 μmol s−1 m−2) days of 30 July to 5 August 2004 in Zurich caused the substance to degrade rapidly with half-life under such condition only
14 h. This implies that should EA gets into the environment, particularly on exposed environmental niches, such as on plant
surfaces through biocontrol product spray, or released from shed diseased leaves, it may have no chance of accumulating to
‘level of concern’. Furthermore, a toxicity assay using Trichoderma atroviride P1 as biosensor showed that photo-degraded EA was not toxic, indicating that no stable toxic by-products were left. 相似文献
18.
Diversity of Soil Nematodes in Areas Polluted with Heavy Metals and Polycyclic Aromatic Hydrocarbons (PAHs) in Lanzhou,China 总被引:1,自引:0,他引:1
This study investigated the soil nematode community structure along the Yellow River in the Lanzhou area of China, and analyzed
the impact of heavy metals (Cd, Pb, Cr, Cu, and Zn) and polycyclic aromatic hydrocarbons (PAHs) on the nematode community.
Soil samples from five locations (named A–E), which were chosen for soil analysis, showed significant differences in their
heavy metal content (p < 0.01), as well as in the variety of nematodes (up to 41 genera) and families (up to 20) that were present. The different
samples also differed significantly in the total PAH content (p < 0.05), as well as the six types of PAH present. Sites A–C showed the most severe contamination with heavy metals and PAHs;
these sites had the lowest abundance of fungivores and omnivore/predators, but the proportion of bacteriovores was the highest
(p < 0.05). Site E, in contrast, showed only minor pollution with heavy metals and PAHs, and it contained the highest abundance
of plant parasites (p < 0.05). Several nematode ecological indicators were found to correlate with concentration of soil pollutants at all the
sites tested: the maturity index (MI, in addition to plant parasites), plant parasite index (PPI), ΣMI (including all the
soil nematodes), Shannon-Wiener diversity index (H′′), and Wasilewska index (WI). Disturbance to the soil environment was more severe when MI, ΣMI, and H′ values were lower. The results of the study show that the abundance and structure of the soil nematode communities in the
sampling locations were strongly influenced by levels of heavy metals and PAHs in the soil. They also show that the diversity
index H′ and the maturity index can be valuable tools for assessing the impact of pollutants on nematodes. 相似文献
19.
Observations of Atmospheric Nitrogen and Phosphorus Deposition During the Period of Algal Bloom Formation in Northern Lake Taihu,China 总被引:5,自引:1,他引:4
Cyanobacterial blooms in Lake Taihu occurred at the end of April 2007 and had crucial impacts on the livelihood of millions
of people living there. Excessive nutrients may promote bloom formation. Atmospheric nitrogen (N) and phosphorus (P) deposition
appears to play an important role in algal bloom formation. Bulk deposition and rain water samples were collected respectively
from May 1 to November 30, 2007, the period of optimal algal growth, to measure the bulk atmospheric deposition rate, wet
deposition rate, and dry deposition rate for total nitrogen (TN; i.e., all species of nitrogen), and total phosphorus (TP;
i.e., all species of phosphorus), in northern Lake Taihu, China. The trends of the bulk atmospheric deposition rate for TN
and the wet deposition rate for TN showed double peaks during the observation period and distinct influence with plum rains
and typhoons. Meanwhile, monthly bulk atmospheric deposition rates for TP showed little influence of annual precipitation.
However, excessive rain may lead to high atmospheric N and P deposition rates. In bulk deposition samples, the average percentage
of total dissolved nitrogen accounting for TN was 91.2% and changed little with time. However, the average percentage of total
dissolved phosphorus accounting for TP was 65.6% and changed substantially with time. Annual bulk atmospheric deposition rates
of TN and TP during 2007 in Lake Taihu were estimated to be 2,976 and 84 kg km−2 a−1, respectively. The results showed decreases of 34.4% and 78.7%, respectively, compared to 2002–2003. Annual bulk deposition
load of TN for Lake Taihu was estimated at 6,958 t a−1 in 2007 including 4,642 t a−1 of wet deposition, lower than the values obtained in 2002–2003. This may be due to measures taken to save energy and emission
control regulations in the Yangtze River Delta. Nevertheless, high atmospheric N and P deposition loads helped support cyanobacterial
blooms in northern Lake Taihu during summer and autumn, the period of favorable algal growth. 相似文献
20.
Fertilizer Management in Watersheds of Two Ramsar Wetlands and Effects on Quality of Inflowing Water
Two field experiments were carried out in the watersheds of two Ramsar wetland areas, Lakes Koronia and Volvi (area A) and
Lakes Mikri and Megali Prespa (area B), to study the effect of application of N fertilizer on wheat yields, the quality of
runoff water, and the quality of stream water. The treatments were a combination of two methods of fertilizer application
(total amount in fall, and 2/3 in fall + 1/3 in spring) at three rates (0, 100, and 200 kg N/ha) with four replications. Concentrations
of NH4
+, NO3
−, NO2
−, P, and Cl− and pH were determined in all water samples. Runoff water quality was not influenced by fertilizer application in either
area. Chemical parameters for water did not differ along the selected watercourses in area B, while in area A they were higher
in the samples taken near Lake Koronia than in the samples taken upstream, indicating that the watercourses are polluted downstream
by nonagricultural sources. The differences in wheat yields between the 100 and 200 kg N/ha application rates were not high.
These results call for better fertilizer management in order to achieve better yields and to diminish the possibility to have
negative effects to the environment. 相似文献