共查询到20条相似文献,搜索用时 31 毫秒
1.
Armenuhi Heqimyan Lilia Narinyan Anna Nikoghosyan Anush Deghoyan Lianna Yeganyan Sinerik Ayrapetyan 《The Environmentalist》2012,32(2):228-235
Age dependency of [3H]-ouabain binding, 45Ca2+ eflux and its magnetosensitivity in rats’ brain cortex and heart muscle tissues were studied. Curves of dose-dependent [3H]-ouabain binding consisted of three components with different affinities (10−7–10−4 M (α1); 10−9–10−7 M (α2); and 10−11–10−9 M (α3)). These curves were also characterized by different dose-dependent kinetics. [3H]-ouabain binding with α3 receptors in brain cortex and heart muscle tissues of young and adult animals had a dose-dependent character, while that
in old ones had a dose-independent character. A 0.2 T static magnetic field (SMF) exposure had modulation effect on ouabain
binding with α1, α2 and α3 receptors in young rats, while in adult ones, only α3 receptors were magnetosensitive. In old animals, SMF exposure had no significant effect on ouabain binding with α3 receptors in brain cortex, while in heart muscle, it had inhibitory effect on it. Age-dependent effect of ouabain impact
on 45Ca2+ efflux showed that all concentrations of ouabain lead to inhibitory effect in young animals’ brain cortex and heart muscle
(with the exception of 10−10 and 10−6 M), while in old ones, it had activation effect as compared with data received without ouabain. SMF exposure in young animals
had activation effect on 45Ca2+ efflux from brain cortex and heart muscle in data without ouabain, and in old rats, 45Ca2+ efflux from brain cortex was magnetic insensitive. In old animals, SMF increased 45Ca2+ efflux even after extra low concentration of ouabain. It is suggested that α3 receptors having a crucial role in the regulation of Na+/Ca2+ exchange serve as age-dependent magnetosensors of excitable cells. 相似文献
2.
Erna Dadasyan Gayane Ayrapetyan Naira Baghdasaryan Yerazik Mikayelyan Sinerik Ayrapetyan 《The Environmentalist》2012,32(2):166-174
It was shown that the 4 Hz 30 dB mechanical vibration (MV) of physiological solution (PS) had modulation effect on snail heart
contractility. However, the nature of metabolic pathway of MV-treated PS-induced effect is not clear yet. It was suggested
that the MV-induced modulation of water molecules dissociation leads to the variation of reactive oxygen species’ level in
cell bathing medium, which could serve as a messenger for switching on the metabolic pathway(s) responsible for modulation
of muscle contractility. The aim of present work was to check this hypothesis and to elucidate the metabolic pathway through
which the effect of MV-treated PS on heart contractility was realized. For this purpose, the effect of MV on heat fusion periods
(HFP) and H2O2 content in PS, as well as on heart contractility, 45Ca2+ efflux, intracellular levels of cGMP and cAMP, muscle hydration, and ouabain binding were studied. It was shown that MV treatment
of PS increased the HFP-(21.33 ± 4%) and decreased the H2O2 content-(5 ± 0.9%). The intracardiac perfusion by MV-treated PS increased the amplitudes of heart contractility, which was
accompanied by the increasing of 45Ca2+ efflux (252.4 ± 16%), elevation of cGMP’s level (42.05 ± 7%), decreasing of cAMP’s level (82.67 ± 7%), increasing of the
tissue hydration (18.64 ± 3%), and increasing of the number of ouabain binding sides (25 ± 4%). It was suggested that MV-induced
increasing of heart muscle contraction amplitudes is due to the decreases of H2O2 content in the medium, which leads to the elevation of heart muscle contractility in result of activation of cGMP-dependent
Na+/Ca2+ exchange in forward regime. 相似文献
3.
The term “phytoremediation” is used to describe the cleanup of heavy metals from contaminated sites by plants. This study
demonstrates phytoremediation potential of Indian mustard (Brasicca juncea (L.) Czern. & Coss.) genotypes for chromium (Cr). Seedlings of 10 genotypes were grown hydroponically in artificially contaminated
water over a range of environmentally relevant concentrations of Cr (VI), and the responses of genotypes in the presence of
Cr, with reference to Cr accumulation, its phytotoxity and anti-oxidative system were investigated. The Cr accumulation potential
varied largely among Indian mustard genotypes. At 100 μM Cr treatment, Pusa Jai Kisan accumulated the maximum amount of Cr
(1680 μg Cr g−1 DW) whereas Vardhan accumulated the minimum (107 μg Cr g−1 DW). As the tolerance of metals is a key plant characteristic required for phytoremediation purpose, effects of various levels
of Cr on biomass were evaluated as the gross effect. The extent of oxidative stress caused by Cr stress was measured as rate
of lipid peroxidation. The level of thiobarbituric acid reactive substances (TBARS) was enhanced at all Cr treatments when
compared to the control. Inductions of enzymatic and nonenzymatic antioxidants were monitored as metal-detoxifying responses.
All the genotypes responded to Cr-induced oxidative stress by modulating nonenzymatic antioxidants [glutathione (GSH) and
ascorbate (Asc)] and enzymatic antioxidants [superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase
(GR)]. The level of induction, however, differed among the genotypes, being at its maximum in Pusa Jai Kisan and its minimum
in Vardhan. Pusa Jai Kisan was grown under natural field conditions with various Cr treatments, and Cr-accumulation capacity
was studied. The results confirmed that Pusa Jai Kisan is a hyperaccumulator of Cr and hypertolerant to Cr-induced stress,
which makes this genotype a viable candidate for use in the development of phytoremediation technology of Cr-contaminated
sites. 相似文献
4.
Omotayo Rafiu Awofolu 《The Environmentalist》2006,26(4):285-293
Groundwater (well water) from a residential area within the vicinity of an industrial estate in Lagos, Nigeria were sampled
and analysed by Flame Atomic Absorption Spectroscopy for their heavy metals content. This was with a view of assessing the
quality of the water, which was being used for domestic activities, especially, drinking usually without treatment. Total
trace metal determination by mineral acid digestion of water samples was applied. This method proved to be better than an
extractive concentration technique in the quality assurance protocols with the recovery range being 90.7 ± 0.006–97.6 ± 0.003%.
Mean concentration of trace metals in water samples ranged from Fe: 0.05–0.47 mg l−1; Al: 0.1–1.54 mg l−1; Cu: 0.14–1.39 mg l−1; Zn: 0.04–0.43 mg l−1; Cd: trace–0.02 mg l−1; Pb: trace–0.03 mg l−1, Mn: 0.01–0.18 mg l−1 and Ni: 0.02–0.11 mg l−1. Physical parameters of water samples examined were within the drinking water safety limits except for conductivity. Results
generally indicate the presence of heavy metal constituents in groundwater samples. Detection of metals such as cadmium and
lead which have serious health implications above WHO and USEPA limits in drinking water gives cause for concern. 相似文献
5.
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
6.
Surindra Suthar 《The Environmentalist》2009,29(1):78-84
Epigeic earthworms (Oligochaeta) have been appeared as key organisms to convert organic waste resources into value-added products,
i.e., vermicompost and worm biomass. The assessment of reproduction potential of composting earthworm may be beneficial for
large-scale earthworm production. Although, the waste minimizing potential of Perionyx excavatus and Perionyx sansibaricus is well proved, but little information is available about their fecundity rate. In this study, the efforts have been made
to explore the growth and reproduction biology of P. excavatus and P. sansibaricus, using cattle waste solid as culture substrate, under laboratory conditions. Earthworms were weighed weekly and number of
cocoons produced per week assessed. Biomass productions, fecundity, maturation, natality all were significantly different
between P. excavatus and P. sansibaricus. The highest mean individual biomass was 767.7 ± 18.4 mg and 612.6 ± 20.6 mg, respectively in P. sansibaricus and P. excavatus. However, the highest cocoon numbers occurred in P. excavatus (492.3 ± 13.6), significantly higher than P. sansibaricus (269.6 ± 17.1). Fecundity was slightly different in both species: 1.38 ± 0.77 cocoons adult worm−1 week−1 (P. excavatus) and 1.58 ± 0.74 cocoons adult worm−1 week−1 (P. sansibaricus). The hatchling success rate (%) was highest in P. excavatus. Overall natality (juveniles adult−1 week−1) was highest in P. sansibaricus (1.52) than P. excavatus (1.26), which suggests that P. sansibaricus may be a better candidate for rapid propagation of earthworms in cattle waste solid. 相似文献
7.
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
8.
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
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.
Ruchi Badola Syed Ainul Hussain Bidyut Kumar Mishra Bidyarani Konthoujam Sneha Thapliyal Parag Madhukar Dhakate 《The Environmentalist》2010,30(4):320-329
This paper examines the economic value of selected ecosystem services of Corbett Tiger Reserve, India. The direct cost was
derived from secondary sources, and indirect and opportunity costs through socioeconomic surveys. For recreational value the
individual approach to travel cost method was used, and to assess carbon sequestration the replacement cost method was used.
The maintenance cost of the reserve was estimated as US $2,153,174.3 year−1. The indirect costs in terms of crop and livestock depredation by wild animals ranged from US $2,153,174.3 year−1. The indirect costs in terms of crop and livestock depredation by wild animals ranged from US 2,408 to US $37,958 village−1 over a period of 5 years. The dependence of local communities was for fuel wood (US $37,958 village−1 over a period of 5 years. The dependence of local communities was for fuel wood (US 7,346 day−1), fodder (US $5,290 day−1), small timber, and other nontimber forest products. The recreational value of the reserve was estimated as US $5,290 day−1), small timber, and other nontimber forest products. The recreational value of the reserve was estimated as US 167,619 year−1. With the cost per visitor being US $2.5, the consumers’ surplus was large, showing the willingness of visitors to pay for
wildlife recreation. The forests of the reserve mitigate carbon worth US $2.5, the consumers’ surplus was large, showing the willingness of visitors to pay for
wildlife recreation. The forests of the reserve mitigate carbon worth US 63.6 million, with an annual flow of US $65.0 ha−1 year−1. The other benefits of the reserve include US $65.0 ha−1 year−1. The other benefits of the reserve include US 41 million through generation of electricity since 1972. The analysis reveals
that, though the benefits outweigh costs, they need to be accrued to local communities so as to balance the distribution of
benefits and costs. 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.
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
14.
Md. Abul Kalam Azad Md. Nozrul Islam Ashraful Alam Hasan Mahmud M. A. Islam M. Rezaul Karim Matiar Rahman 《The Environmentalist》2009,29(4):436-440
A pot-culture experiment was conducted in open-field conditions with highly cultivated locally transplanted (T) aman rice
(Oryza sativa L.) named BR-22 in arsenic (As)-amended soil (0, 1.0, 5.0, 10.0, 20.0, 30.0, 40.0 and 50.0 mg kg−1 As) of Bangladesh to see the effect of As on the growth, yield and metal uptake of rice. Arsenic was applied to soil in the
form of sodium arsenate (Na2HAsO4). Arsenic affected the plant height, tiller and panicle numbers, grain and straw yield of T-aman rice significantly (P ≤ 0.05). The grain As uptake of T-aman rice was found to increase with increase of As in soil and a high grain As uptake
was observed in the treatments of 30–50 mg kg−1 As-containing soil. These levels exceed the food hygiene concentration limit of 1.0 mg kg−1 As. However, the straw As uptake varied significantly (P ≤ 0.05) from a low concentration of As in soil (5 mg kg−1) and the highest uptake was noticed in 20 mg kg−1 As treatment. 相似文献
15.
The effects of livestock grazing on selected riparian and stream attributes, water chemistry, and algal biomass were investigated
over a two-year period using livestock enclosures and by completing stream surveys in the Cypress Hills grassland plateau,
Alberta, Canada. Livestock enclosure experiments, partially replicated in three streams, comprised four treatments: (1) early
season livestock grazing (June–August), (2) late season livestock grazing (August–September), (3) all season grazing (June–September),
and (4) livestock absent controls. Livestock grazing significantly decreased streambank stability, biomass of riparian vegetation,
and the extent to which aquatic vegetation covered the stream channels compared with livestock-absent controls. Water quality
comparisons indicated significant differences among the four livestock grazing treatments in Battle and Graburn creeks but
not in Nine Mile Creek. In Graburn Creek, the concentration of total phosphorus in the all-season livestock grazing treatment
was significantly higher than that in the livestock-absent control, and the early season and late season grazing treatments.
Concentrations of soluble reactive phosphorus in the all-season livestock grazing treatment also exceeded that in livestock-absent
control. In contrast, differences in water quality variables in the remaining 22 comparisons (i.e., 22 of the total 24 comparisons)
were minor even when differences were statistically significant. Effects of livestock grazing on algal biomass were variable,
and there was no consistent pattern among creeks. At the watershed scale, spatial variation in algal biomass was related (P < 0.05) with concentrations of NO2
− + NO3
− and soluble reactive phosphorus in two of the four study creeks. Nutrient diffusing substrata experiments showed that algal
communities were either nitrogen-limited or not limited by nutrients, depending on stream and season. 相似文献
16.
Textile mill waste can be vermicomposted if it is mixed in the range of 20–30% with cow dung. This article reports the effect
of inoculation, of nitrogen fixing Azotobacter chroococcum strain; Azospirillum brasilense strain and phosphate solubilizing Pseudomonas maltophila, on nitrogen and phosphorus content of vermicomposts prepared from cow dung (CD) and cow dung spiked textile mill sludge
(CD + STMS). The CD vermicompost was more supportive to the growth and multiplication of all the three bacteria than CD + STMS
vermicompost. In Azotobacter chroococcum treated vermicomposts maximum nitrogen content was recorded between 45 and 60 days [CD␣vermicompost (25.9 ± 0.45 g kg−1) and CD + STMS vermicompost (20.6 ± 0.62 g kg−1)] followed by Azospirillum brasilense inoculation [CD vermicompost (19.4 ± 0.60 g kg−1) and CD + STMS vermicompost (18.6 ± 0.17 g kg−1)]. Phosphorus content in Pseudomonas maltophila inoculated CD vermicompost was 20.8 ± 0.20 g kg−1 and CD + STMS vermicompost was 13.4 ± 0.45 g kg−1 after 75th day of inoculation. 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.
The hydrochemical study of the surface water along with land-use/land-cover study of its catchment area is useful for determining
its suitability for support to aquatic ecosystem and agricultural purposes. The surface water quality around the wetland in
Sugadaira region, Japan, is being affected both by complex hydrogeochemical processes and by anthropogenic activity, mainly
intensive agricultural practices. Statistical analysis was carried out in this study using surface water chemistry data to
enable hydrochemical evaluation of the water quality based on the ionic constituents, water types, and factors controlling
water quality. Results show that the general trend of various ions was found to be Ca2+ > Mg2+ > Na+ > K+ and HCO3
− > NO3
− > SO4
2− > Cl−. Spatial distribution of water chemistry shows that enrichment of NO3
− has taken place along one side of the wetland that is exposed directly to human settlement and agricultural practices. This
study is vital considering that pollution in a wetland indicates that poor health of water resources in the region not only
makes the situation alarming but also calls for immediate attention. 相似文献
19.
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
20.
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