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1.
Size and resin fractionations of dissolved organic matter and trihalomethane precursors from four typical source waters in China 总被引:3,自引:0,他引:3
Wei Q Wang D Wei Q Qiao C Shi B Tang H 《Environmental monitoring and assessment》2008,141(1-3):347-357
Dissolved organic matter (DOM) and its potential to form disinfection by-products (DBPs) during drinking water treatment raise
challenges to water quality control. Understanding both chemical and physical characteristics of DOM in source waters is key
to better water treatment. In this study, the DOM from four typical source waters in China was fractionated by XAD resin adsorption
(RA) and ultrafiltration (UF) techniques. The trihalomethane formation potential (THMFP) of all fractions in the DOM were
investigated to reveal the major THM precursors. The fraction distributions of DOM could be related to their geographical
origins in a certain extent. The dominant chemical fraction as THM precursors in the DOM from south waters (East-Lake reservoir
in Shenzhen and Peal rivers in Guangzhou) was hydrophobic acid (HoA). The size fraction with molecular weight (MW) <1 kDa
in both south waters had the highest THMFP. The results of cluster analysis showed that the parameters of fractions including
DOC percentage (DOC%), UV254%, SUVA254 (specific UV254 absorbance) and THMFP were better for representing the differences of DOM from the studied waters than specific THMFP (STHMFP).
The weak correlation between SUVA254 and STHMFP for either size or XAD fractions suggests that whether SUVA254 can be used as an indicator for the reactivity of THM formation is highly dependent on the nature of organic matter. 相似文献
2.
The inorganic nitrogen transformations occurring at a municipal waste leachate treatment facility were investigated. The treatment
facility consisted of a collection well and an artificial wetland between two aeration ponds. The first aeration pond showed
a decrease in ammonium (from 3480 (± 120) to 630(± 90) mg ⋅ L−1), a reduction in inorganic nitrogen load (3480 to 1680 mg N ⋅ L−1), and an accumulation of nitrite (< 1.3 mg-N ⋅ L−1 in the collection well, to 1030 mg-N ⋅ L−1). Incomplete ammonium oxidation was presumably the result of the low concentration of carbonate alkalinity (∼2 mg ⋅ L−1), which may cause a limitation in the ammonium oxidation rate of nitrifiers. Low carbonate alkalinity levels may have been
the result of stripping of CO2 from the first aeration pond at the high aeration rates and low pH. Various chemodenitrification mechanisms are discussed
as the reason for the reduction in the inorganic nitrogen load, including; the reduction of nitrite by iron (II) (producing
various forms of gaseous nitrogen); and reactions involving nitrous acid. It is suggested that the accumulation of nitrite
may be the result of inhibition of nitrite oxidizers by nitrous acid and low temperatures. Relative to the first aeration
pond, the speciation and concentration of inorganic nitrogen was stable in the wetlands and 2nd aeration pond. The limited
denitrification in the wetlands most probably occurred due to low concentrations of organic carbon, and short retention times. 相似文献
3.
In an effort to assess current and future water quality of the only perennial river in southeastern Botswana, this study presents
water quality monitoring and modeling results for the effluent-dependent Notwane River. The water quality along the Notwane
River, pre- and post-implementation of secondary wastewater treatment, was compared and results demonstrated that water quality
improved after the new wastewater treatment plant (WWTP) went online. However, stream standards for chemical oxygen demand,
total dissolved phosphorous, and fecal coliform were exceeded in most locations and the critical dissolved oxygen (DO) reached
concentrations of less than 4 mg L−1. High dissolved P concentrations and intense macrophyte growth at the impounding ponds and at sites within 30 km of the effluent
waste stream confluence suggest that eutrophication was a function of P release from the ponds. Results of DO modeling demonstrated
that an unpolluted inflow at approximately 10 km downstream of the confluence was responsible for raising DO concentrations
by 2.3 mg L−1, while SOD was responsible for a decline in DO concentrations of 1.4 mg L−1 at 6 km downstream of the confluence. Simulations also showed higher DO concentrations during winter months, when water temperatures
were lower. Simulations, in which the distributed biochemical oxygen demand (BOD) loading from cattle excrement was decreased,
produced nominal increases in DO concentrations. An increase in WWTP BOD loadings to projected 2020 values resulted in a 1.3
mg L−1 decrease in the critical DO concentration. Furthermore, a decrease in treatment plant efficiency, from 94% to 70% BOD removal,
produced critical DO concentrations and anoxia along much of the modeled reach. This has significant implications for Gaborone,
especially if decreased WWTP efficiency occurs as a result of the expected future increase in pollutant loadings. 相似文献
4.
Seasonal variation of the concentrations of trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were measured by ICP-AES
in the water and sediment from the Saricay Stream, Geyik Dam and Ortakoy Well in the same basin. Comparisons between trace
metal concentrations in water and sediment in three sources (Stream, Dam and Well) were made. The concentrations of a large
number of trace metals in the water and sediment were generally higher in the Stream than in the Well and Dam, particularly
in summer. Trace metal concentration ranges in sediments of the Saricay Stream and its sources showed very wide ranges (as
mass ratio): Co: 5–476 μg g−1, Cr: 15–1308 μg g−1, Cu: 7–128 μg g−1, Fe: 1120–13210 μg g−1, Mn: 150–2613 μg g−1, Ni: 102–390 μg g−1, Pb: 0.7–31.3 μg g−1 and Zn: 18–304 μg g−1, whereas Cd was not detected. Trace metal concentration ranges found in waters were: Co: 9.5–20.7 μg L−1, Cr: 20.3–284 μg L−1, Cu: 170–840 μg L−1, Fe: 176–1830 μg L−1, Mn: 29.3–387 μg L−1, and Ni: 4.3–21.9 μg L−1. Among the trace metals studied, Cd and Zn in two seasons and Pb in winter were usually not detected or in the recommended
levels. In addition, Cd was not detected in the sediment during the winter season. The analysis of variance (one-way ANOVA)
and correlation matrix was employed for the sediment and water samples of the two field surveys (summer and winter) comparison.
The three sources showed differences in metal contents. The metal levels in sediments displayed marked seasonal and regional
variations, which were attributed to anthropogenic influences and natural processes. In the Saricay Stream, high values of
metals during the dry season showed an anthropological effect from small industry firms, e.g.: an olive mill and a dairy farm
or water dilution during summer seasons. Finally, the pollution in this basin probably originated from small industrial, low
quality coal-burned thermal power plants, and particularly agricultural and domestic waste discharges. 相似文献
5.
Total selenium (Se) and water-soluble Se in soil, and Se in a shallow groundwater were hydrogeochemically researched in an
alluvial fan area in Tsukui, Central Japan. The water-soluble Se was estimated at average level of 2.6 ± 1.2μg Se kg−1 dry soil (± SD, n = 25), showing less than 1% of the total Se (349–508μg Se kg−1 dry soil) in soil. The monthly Se concentration in groundwater was average 2.2μg,L−1, ranging 1.6–2.4μg,L−1 during 2001–2003. The Se in groundwater significantly decreased with increasing groundwater level after rainfall. This result
indicated that Se-bearing water percolated with relatively low Se concentration through the soil layer. According to our prediction
model of linear regression curve on the observation data, Se concentration in the groundwater was estimated to be increasing
with the very low rate of 4.35 × 10−3μg Se L−1,yr−1. The hydrogeochemical research and the result of the prediction model showed that any explosive increase of Se will hardly
occur in this groundwater without an anthropogenic Se contamination. 相似文献
6.
Starr M Ukonmaanaho L Sibley PK Hazlett PW Gordon AM 《Environmental monitoring and assessment》2007,125(1-3):123-136
Open precipitation and throughfall was collected at a Norway spruce stand in Finland using funnel-type collectors and at a
black spruce stand in Canada using trough-type collectors. The presence or absence of a rim on the funnel, funnel diameter
(9, 14 and 20 cm) and length of sampling period (1, 2 and 4 weeks) on monthly values were evaluated at the Norway spruce stand,
and the number of collectors required for defined levels of accuracy and precision of throughfall loads to be reached and
the influence of the spatial arrangement of collectors on solute concentrations was studied at both stands. The presence of
a rim had no significant effect on open precipitation and throughfall amounts, but did on throughfall DOC, Ca2+, Mg2+, K+, Na+ and Cl− ion loads. Deposition loads increased with decreasing funnel diameter; for open precipitation, this was due to increased
catch efficiency while for throughfall the increase was attributed to canopy interaction and leaching of litter trapped in
the collectors. Calculated monthly H+ loads decreased and those for all other constituents increased with collection period length. Using 15 collectors at the
Norway spruce stand would allow throughfall loads to be determined to within 20% of the true mean weekly value with a confidence
level of 95% for most solute, but not for NH4
+–N, NO3
−–N, Mg2+ and SO4
2−-S. Using 15 trough collectors, the same confidence level at the more heterogeneous black spruce stand would only be achieved
for H+, Cl−, DOC and SO4
2−-S loads. In both stands, using either random or systematic placements of throughfall collectors gave similar results. 相似文献
7.
Celik K 《Environmental monitoring and assessment》2006,117(1-3):261-269
Regression and correlation analyses were used to predict responses of phytoplankton biomass (chlorophyll) (μg L−1) to nitrate (NO3) (mg L−1), phosphate (PO4) (mg L−1) and ammonium (NH4) (mg L−1) dynamics in the shallow hypertrophic Lake Manyas, Turkey. Nutrient concentrations showed a descending gradient with distance,
while chlorophyll concentrations showed an ascending gradient with the distance from the Sığırcı Inlet to the Karadere Outlet.
Higher nutrient concentrations did always not coincide with higher chlorophyll concentrations. The results showed that regression
models developed using seasonal data were more accurate in predicting chlorophyll concentrations than those developed using
the pooled data from whole year (based on R
2 and the difference between the measured and predicted values). The findings also revealed that within a single large shallow
lake, chlorophyll-nutrient relationships might show significant variations spatially. The objective of this study was to determine
the seasonal and spatial variations in the relationships between chlorophyll, nitrate, phosphate and ammonium in the shallow
hypertrophic Lake Manyas, Turkey. 相似文献
8.
To assess the potential for treated wastewater irrigation to impact levels of fecal indicator bacteria (FIB) and salinity
in irrigated soils, levels of Escherichia coli, Enterococcus, and environmental covariates were measured in a treated wastewater holding pond (irrigation source water), water leaving
the irrigation system, and in irrigated soils over 2 years in a municipal parkland in Arizona. Higher E. coli levels were measured in the pond in winter (56 CFU 100 mL−1) than in summer (17 CFU 100 mL−1); however, in the irrigation system, levels of FIB decreased from summer (26 CFU 100 mL−1) to winter (4 CFU 100 mL−1), possibly related to low winter water use and corresponding death of residual bacteria within the system. For over 2 years,
no increase in FIB was found in irrigated soils, though highest E. coli levels (700 CFU g−1 soil) were measured in deeper (20–25 cm) soils during summer. Measurements of water inputs vs. potential evapotranspiration
indicate that irrigation levels may have been sufficient to generate bacterial percolation to deeper soil layers during summer.
No overall increase in soil salinity resulting from treated wastewater irrigation was detected, but distinct seasonal peaks
as high as 4 ds m−1 occurred during both summers. The peaks significantly declined in winter when surface ET abated and more favorable water
balances could be maintained. Monitoring of seasonal shifts in irrigation water quality and/or factors correlated with increases
and decreases in FIB will aid in identification of any public health or environmental risks that could arise from the use
of treated wastewater for irrigation. 相似文献
9.
This paper applies artificial neural network (ANN) to model the observed effluent quality data. The ANN’s structure, involving
the number of hidden layer and node and their connection, is determined endogenously by resorting to the compromise of data
cost minimization and prediction accuracy maximization. To obtain the best compromise possible, the model introduces an aspiration
variable (μ) that represents the level of aspiration achieved in one objective and the conjugate of μ, (1 − μ), represents level of aspiration achieved in the other objective. Because a massive amount of calculation is required, the
model applies genetic algorithm (GA) for its computational flexibility and capability to ensure global solution. Feasibility
and practicality of the model is tested by a case study with a set of 150 daily observations on 17 operational variables and
quality parameters at an industrial wastewater treatment plant (WTP) located in southern Taiwan. Of these 17 variables open
to selection, only 6 variables, wastewater flow rate (Q), CN−, SS, MLSS, pH and COD are selected by the model to achieve the maximum accuracy of prediction, 0.94, with a total cost of
5,950 NT$. By constraining budget availability, the variables included in the model are reduced in number, causing a concomitant
reduction in prediction accuracy, that is, by varying μ (aspiration level of accuracy), a trajectory of cost and accuracy is generated. The calculation results a cost of 3,650 NT$
and 0.54 accuracy for the case with variables including flow rate, SCN− and SS in equalization basin; aeration tank hydraulic retention time (HRT) and percentage of returned sludge (R%) are selected for building the prediction model when the importance of required budget is equal to the accuracy of prediction
model. In addition, when required cost for building ANN model is between 3,650 NT$ and 3,900 NT$, the marginal return of budget
input is highest in the entire range of calculation. 相似文献
10.
In this work, water and sediment samples were collected from three different stations located along the Sakarya river between
May and September 2003. Lead, copper, chromium, zinc, nickel and cadmium concentrations were determined by using solvent extraction
and flame atomic absorption spectrometric method. The results show that differences based upon sampling times, regions, sediment
and water samples were observed. The mean levels of copper, nickel, chromium, lead, cadmium, zinc for sediment samples are;
4.630 μg g−1, 13.520 μg g−1, 8.780 μg g−1, 2.550 μg g−1, 9.990 μg g−1 and for water samples are; 0.851 μg g−1, 1.050 μg g−1, 0.027 μg g−1, 1.786 μg g−1, 0.236 μg g−1, 0.173 μg g−1, respectively. 相似文献
11.
Hydrogeochemical characterization of contaminated groundwater in Patancheru industrial area,southern India 总被引:1,自引:0,他引:1
The groundwater is one of the most contaminated natural resources in Patancheru industrial area due to unplanned and haphazard
industrial growth and urbanization without following basic pollution control norms. The rapid industrialization initiated
in early 1970 has started showing up its after effects few years later in the form of physiochemical contamination of the
both surface and groundwater bodies of the area. It has resulted in local people being deprived of safe drinking water, plant
and aquatic life has severely affected, and situation is deteriorating over the years in the area in spite of some preventive
and remedial measures being initiated. The focus of the present study is to understand the chemical characteristics of groundwater
and geochemical processes the contaminant water is undergoing which are normally imprinted in its ionic assemblages. The water
samples collected in pre- and post-monsoon seasons from forty two groundwater and four surface water sources were analyzed
for major constituents such as Ca2+, Mg2+, Na+, K+, CO3−, HCO3−, Cl−, SO42−, NO3−, and F−, and selected samples were tested for ten important trace metals like Fe, Pb, Bi, Mn, Cr, Co, Ni, Cu, Zn, and Cd. Na+ among cations and Cl− among anions dominate the water in both the seasons where as Ca2+, HCO3−, and Cl− show significant reduction in their ionic strength in post-monsoon. The groundwater in general is of mixed type, but most
of it belong to Na+–Cl−, Na+–HCO3−, Ca2+–Mg2+–HCO3−, and Ca2+–Mg2+–Cl− facies. The Na+ and Ca2+ are in the transitional state with Na+ replacing Ca2+ and HCO3−–Cl− due to physiochemical changes in the aquifer system. The evaluation of hydrochemistry through various ionic indices, ratios,
and plots suggest that silicate–carbonate weathering, ion exchange, dissolution, and evaporation processes are responsible
for origin of the present chemical status of the groundwater which is also controlled by the contamination from extraneous
sources that could have accelerated the dissolution processes. Gibbs plots authenticate that the evolution of water chemistry
is influenced by interaction of percolating water with aquifer matrix apart from anthropogenic enrichment of elements which
get over concentrated due to evaporation. 相似文献
12.
Heavy metal pollution of water resources can be apprehended in East Singhbhum region which is a highly mineralised zone with
extensive mining of copper, uranium and other minerals. Ten groundwater samples were collected from each site and the heavy
metal analysis was done by atomic absorption spectrophotometer. Analysis of the results of the study reveals that the concentration
of iron, manganese, zinc, lead, copper and nickel in groundwater of Bagjata mining area ranged 0.06–5.3 mg l − 1, 0.01–1.3 mg l − 1, 0.02–8.2 mg l − 1, 1.4–28.4 μg l − 1, 0.78–20.0 μg l − 1 and 1.05–20.1 μg l − 1, respectively. In case of Banduhurang mining area, the range was 0.04–2.93 mg l − 1, 0.02–1.1 mg l − 1, 0.01–4.68 mg l − 1, 1.04–33.21 μg l − 1, 1.24–18.7 μg l − 1 and 1.06–14.58 μg l − 1, respectively. The heavy metals were found to be below the drinking water standards (IS:10500 1993) except iron (0.3 mg l − 1) and manganese (0.1 mg l − 1). The hazard quotients of the heavy metals for drinking water were below 1 posing no threat due to intake of water to the
people for both the areas. 相似文献
13.
Aerosol samples for dry deposition and total suspend particulates (TSP) were collected from August to November of 2003 in central Taiwan. Ion chromatography was used to analyze the related water-soluble ionic species (Cl−, NO3
−, SO4
2−, Na+, NH4
+, K+, Mg2+ and Ca2+). The results obtained in this study indicated that the ambient air particulate mass concentrations in the daytime period (averaged 975.4 μg m−3) were higher than the nighttime period (averaged 542.1 μg m−3). And the daytime dry deposition fluxes (averaged 58.12 μg m−2 sec−1) were about 2.2 times as that of nighttime dry deposition fluxes (averaged 26.54 μg m−2 sec−1) of the downward dry deposition. The average values downward and upward of dry deposition fluxes for the weekend period were almost higher than the weekday period for either daytime or nighttime period. Furthermore, the average daytime dry deposition fluxes (averaged 26.37 μg m−2 sec−1) were also about 2.3 times as that of nighttime dry deposition fluxes (averaged 11.52 μg m−2 sec−1). Moreover, the results also indicate that SO4
2− and Ca2+ have higher average composition for total suspended particulates in the daytime period while Ca2+, SO4
2−, and Na+ have the higher average composition for total suspends particulates in the nighttime period. 相似文献
14.
The activity concentrations of soil samples collected from thirty different locations of Malwa region of Punjab were determined
by using HPGe detector based on high-resolution gamma spectrometry system. The range of activity concentrations of 226Ra, 232Th and 40K in the soil from the studied areas varies from 18.37 Bq kg−1 (Sangrur) to 53.11 Bq kg−1 (Sitoguno), 57.28 Bq kg−1 (Dhanola) to 148.28 Bq kg−1 (Sitoguno) and 211.13 Bq kg−1 (Sunam) to 413.27 Bq kg−1 (Virk Khera) with overall mean values of 35 Bq kg−1, 80 Bq kg−1and 317 Bq kg−1 respectively. The absorbed dose rate calculated from activity concentration of 226Ra, 232Th and 40K ranges between 8.47 and 24.48, 35.68 and 92.38, and 8.74 and 17.11 nGy h−1, respectively. The total absorbed dose in the study area ranges from 58.08 nGy h−1 to 130.85 nGy h−1 with an average value of 79.11 nGy h−1. The calculated values of external hazard index (Hex) for the soil samples of the study area range from 0.35 to 0.79. Since these values are lower than unity, therefore, according
to the Radiation Protection 112 (European Commission. Radiation Protection 112 1999) report, soil from these regions is safe and can be used as a construction material without posing any significant radiological
threat to population. 相似文献
15.
In this work assays involving chlorinated water samples, which were previous spiked with humic substances or algae blue green
and following the production of the THMs for 30 days is described. To implement the assays, five portions of 1,000 ml of water
were stored in glass bottles. The water samples were treated with solutions containing 2, 3, 4 and 5 mg l−1 chlorine. The samples aliquots (60 ml) were transferred into the glass vials, 10 ml were removed to have a headspace and
100 μl of the 10 mg l−1 pentafluortoluene bromide solution was added to each vial. The extraction step was performed by adding 10 g of Na2SO4 followed by 5 ml of n-pentane. The vials were stopped with a TFE-faced septum and sealed with aluminum caps. The generated THMs were determined
by gas chromatography with electron capture detector using reference solutions with concentration ranging from 8 to 120 μg
l−1 THMs. Three assays were monitored during 30 days and chloroform was the predominant compound found in the water samples,
while other species of THMs were not detected. The results showed that when the chlorine concentration was increased in water
samples containing algae the concentration of THM varied randomly. Nevertheless, in water samples containing humic substances
the increase of the THM concentration presented a relationship with the chlorine concentration. It was also observed that
chloroform concentration increased with the elapsed time up to one and six days to water samples spiked with humic substances
and algae blue green, respectively and decreased along 30 days. By other hand, assays performed using water samples containing
decanted algae material showed that THM was not generated by the chlorine addition. 相似文献
16.
Elevated levels of selenium have been found in water and aquatic biota downstream from two open-pit coal mines in the Rocky Mountain foothills of Alberta. Birds are particularly sensitive to excessive dietary selenium. However, there is relatively little information on selenium accumulation in birds' eggs on fast-flowing mountain streams. We determined levels of selenium in water samples, caddisfly larvae and eggs of American dippers (Cinclus mexicanus) nesting on the Gregg River, downstream from the mines, and on reference streams in the same general vicinity. Selenium levels (mean, 95% confidence limits) in water samples and caddisflies collected from sites near dipper nests on the Gregg River (water: 4.26, 1.90–9.56 μg L−1; caddisflies: 8.43, 7.51–9.46 μg g dry wt−1) were greater than those collected from sites near nests on reference rivers (water: 0.38, 0.21–0.71 μg L−1; caddisflies: 4.65, 4.35–4.97 μg g dry wt−1). The mean (± 1SE) selenium level in dipper eggs from the Gregg River (6.3 ± 0.2 μg g−1 dry wt) was significantly higher than it was in eggs from reference streams (4.9 ± 0.2 μg g−1 dry wt). Concentrations of selenium in eggs were significantly correlated with those in water samples (r = 0.45). The maximum selenium level in eggs from the Gregg River (9.0 μg g−1) may have been high enough to warrant concern from an ecotoxicological perspective. The American dipper can serve as a useful bioindicator of selenium contamination in mountainous, lotic ecosystems. 相似文献
17.
Evrendilek F Berberoglu S Taskinsu-Meydan S Yilmaz E 《Environmental monitoring and assessment》2006,119(1-3):527-543
Abstact Aboveground biomass, aboveground litterfall, and leaf litter decomposition of five indigenous tree stands (pure stands ofPinus brutia,Pinus nigra,Cedrus libani,Juniperus excelsa, and a mixed stand ofAbies cilicica,P. nigra, andC. libani) were measured in an eastern Mediterranean evergreen needleleaf forest of Turkey. Measurements were converted to regional scale estimates of carbon (C) stocks and fluxes of forest ecosystems, based on general non-site-specific allometric relationships. Mean C stock of the conifer forests was estimated as 97.8± 79 Mg C ha−1consisting of 83.0 ± 67 Mg C ha−1in the aboveground and 14.8 ± 12 Mg C ha−1in the belowground biomass. The forest stands had mean soil organic carbon (SOC) and nitrogen (SON) stocks of 172.0 ± 25.7 Mg C ha−1and 9.2 ± 1.2 Mg N ha−1, respectively. Mean total monthly litterfall was 376.2± 191.3 kg C ha−1, ranging from 641 ± 385 kg C ha−1forPinus brutiato 286 ± 82 kg C ha−1forCedrus libani. Decomposition rate constants (k) for pine needles were 0.0016 forCedrus libani, 0.0009 forPinus nigra, 0.0006 for the mixed stand, and 0.0005 day−1forPinus brutiaand
Juniperus excelsa. Estimation of components of the C budgets revealed that the forest ecosystems were net C sinks, with a mean sequestration rate of 2.0 ± 1.1 Mg C ha−1 yr−1ranging from 3.2 ± 2 Mg C ha−1forPinus brutiato 1.6 ± 0.6 Mg C ha−1forCedrus libani. Mean net ecosystem productivity (NEP) resulted in sequestration of 98.4 ± 54.1 Gg CO2 yr−1from the atmosphere when extrapolated for the entire study area of 134.2 km2(Gg = 109 g). The quantitative C data from the study revealed the significance of the conifer Mediterranean forests as C sinks 相似文献
18.
Kumar KS Suvardhan K Rekha D Kiran K Jayaraj B Janardhanam K Chiranjeevi P 《Environmental monitoring and assessment》2007,127(1-3):67-72
Facile, selective and sensitive spectrophotometric method has been developed for the determination of bendiocarb in its insecticidal
formulations, fortified water, food grains, agriculture wastewater and agriculture soil samples with prepared reagents. The
method was based on alkaline hydrolysis of the bendiocarb pesticide, and the resultant hydrolysis product of bendiocarb was
coupled with 2,6-dibromo-4-methylaniline to give a yellow color product with λmaxof457 nmorcouplingwith2, 6−dibromo−4−nitroanilinetoproducearedcoloredproductwithλmax
of474~nmorcouplingwith2, 4, 6−tribromoanilinetoformorangeredcoloredproducthasaλmax
of465 nm.Underoptimalconditions, Beer'slawrangefor2, 6−dibromo−4−methylaniline(DBMA)wasfoundtobe0.6−−14.0~μgmL
-1, 0.8−−10.0 μgmL
-1
for2, 6−dibromo−4−nitroaniline(DBNA)and0.4−−10.0 μgmL
-1
for2, 4, 6−tribromoaniline(TBA).Themolarabsorptivityofthecolorsystemswerefoundtobe4.126~×~104
lmol
-1 cm
-1
forDBMA, 3.254×104
l~mol
-1 cm
-1
forDBNAand2.812×104
lmol
-1 cm
-1
forTBA.Sandell'softhecolorreactionsare0.018 μgcm
-2(DBMA), 0.052 μgcm
-2(DBNA)and0.065 μgcm
-2$ (TBA) respectively. The effect of the non-target species on the determination of bendiocarb was studied. The formation of
colored derivatives with the coupling agents is instantaneous and stable for 18 h, 30 h, and 12 h. Performance of the proposed
methods were compared statistically in terms Student's F and t-tests with the reported methods. 相似文献
19.
Al-Momani IF Momani KA Jaradat QM Massadeh AM Yousef YA Alomary AA 《Environmental monitoring and assessment》2008,136(1-3):209-218
Wet and dry deposition samples were collected in the capital of Jordan, Amman. Concentrations of Al, Ba, Bi, Cd, Co, Cr, Cu,
Mn, Mo, Ni, Pb, Sb, V, Zn, Fe, Sr, Mg2+, Ca2+, Na+, K+, Cl−, NO3
− and SO4
2−, along with pH were determined in collected samples. Mean trace metal concentrations were similar or less than those reported
for other urban regions worldwide, while concentrations of Ca2+ and SO4
2− were among the highest. High Ca2+ concentrations were attributed to the calcareous nature of the local soil and to the influence of the Saharan dust. However,
high SO4
2− concentrations were attributed to the influence of both anthropogenic and natural sources. Except for Cl−, NO3
−, SO4
2− and Cu, monthly dry deposition fluxes of all measured species were higher than wet deposition fluxes. The annual wet deposition
fluxes of trace metals were much lower than those reported for other urban areas worldwide. 相似文献
20.
Kumar KS Suvardhan K Rekha D Kiran K Rao GC Jayaraj B Janardhanam K Chiranjeevi P 《Environmental monitoring and assessment》2007,129(1-3):271-276
Facile, selective and sensitive spectrophotometric method has been developed for the determination of carbosulfan in insecticidal
formulations, fortified water, food grains, agriculture wastewater and soil samples with newly synthesized reagents. The method
was based on acid and alkaline hydrolysis of the carbosulfan pesticide, and the resultant hydrolysis product of carbosulfan
was coupled with 2,6-dibromo-4-methylaniline to give a yellow color product with λ
max of 464 nm or interaction with 2,6-dibromo-4-nitroaniline to produce yellow colored product with λ
max of 408 nm or coupling with 2,4,6-tribromoaniline to form red colored product has a λ
max of 471 nm. Under optimal conditions, Beer’s law range for 2,6-dibromo-4-methylaniline (DBMA) was found to be 0.2–12.0 μg
ml−1, 0.6–16.0 μg ml−1 for 2,6-dibromo-4-nitroaniline (DBNA) and 0.4–15.0 μg ml−1 for 2,4,6-tribromoaniline (TBA). The molar absorptivity of the color systems were found to be 3.112 × 104 l mol−1 cm−1 for DBMA, 3.214 × 104 l mol−1 cm−1 for DBNA and 3.881 × 104 l mol−1 cm−1 for TBA. Sandell’s of the color reactions are 0.013 μg cm−2 (DBMA), 0.012 μg cm−2 (DBNA) and 0.011 μg cm−2 (TBA) respectively. The effect of the non-target species on the determination of carbosulfan was studied to enhance the selectivity
of the proposed methods. The formation of colored derivatives with the coupling agents is instantaneous and stable for 28,
30, and 26 h. Performance of the proposed methods were compared statistically in terms Student’s F and t-tests with the reported methods.
An erratum to this article can be found at 相似文献