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1.
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
2.
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
3.
Bergasa O Ramírez R Collado C Hernández-Brito JJ Gelado-Caballero MD Rodríguez-Somozas M Haroun RJ 《Environmental monitoring and assessment》2007,127(1-3):127-133
In order to assess the extent of metal contamination at rocky shores of the Canarian Archipelago, metal concentrations have
been measured in Patella piperata (Gould, 1846), using the standard atomic absorption spectrophotometer technique. Ranges of elements concentrations measured
(in μg g−1) found in the biota were: Cd (0.36 ± 0.26 μg g−1 dry wt.), Cu (2.05 ± 0.91 dry wt.), Pb (1.57 ± 1.14 μg g−1dry wt.) and Zn (10.37 ± 4.60 μg g−1 dry wt.). Variation in metal concentrations in Patella, was tested by using non-parametric statistical methods. Cd content had a maximum in the Archipelago Chinijo, northward of
Lanzarote Island. The metal concentrations recorded at the clean stations may be considered carefully if they are used like
background levels. 相似文献
4.
Twelve samples each of soil and ground water were collected from paddy-wheat, paddy-cotton, sugarcane fields and tube wells
from same or near by fields around Hisar, Haryana, India during 2002–2003 to monitor pesticide residues. Residues were estimated
by GC-ECD and GC-NPD systems equipped with capillary columns for organochlorine, synthetic pyrethroid and organophosphate
insecticides. In soil, HCH (0.002–0.051 μg g−1), DDT (0.001–0.066 μg g−1), endosulfan (0.002–0.039 μg g−1) and chlordane (0.0002–0.019 μg g−1) among organochlorines, cypermethrin (0.001–0.035 μg g−1) and fenvalerate (0.001–0.022 μg g−1) among synthetic pyrethroids and chlorpyriphos (0.002–0.172 μg g−1), malathion (0.002–0.008 μg g−1), quinalphos (0.001–0.010 μg g−1) among organophosphates were detected. Dominant contaminants were DDT, cypermethrin and chlorpyriphos from the respective
groups. In water samples, HCH, DDT, endosulfan and cypermethrin residues were observed frequently. Only chlorpyriphos among
organophosphates was detected in 10 samples. On consideration of tube well water for drinking purpose, about 80% samples were
found to contain residues above the regulatory limits. 相似文献
5.
In this study, the relationship between some physico-chemical properties of soils and lead contamination in soil due to emission
from industrial operations in Samsun province of Turkey was investigated. The extent of timely contamination was studied by
comparing the obtained results with the results of the study conducted in the same region in 1998. An area of 225 km2 (15 km × 15 km), which was divided into 1000 × 1000 m grid squares (16 lines in the east and south directions), was selected
within the industrial area. The total of 256 grid points was obtained and soil samples were collected from three depths (0–5,
5–15, and 15–30 cm) of each grid center in 2004. The total Pb concentrations of soil samples were determined as 65.84–527.04
μg g−1 at 0–5 cm in depth, 58.50 – 399.54 μg g−1 at 5–15 cm in depth, and 44.65–330.07 μg g−1 at 15–30 cm in depth. DTPA-extractable Pb concentrations of soils were found to be in the range of 1.52–9.03 μg g−1, 0.54–7.09 μg g−1, 0.19–6.13 μg g−1 at 0–5, 5–15, and 15–30 cm depths, respectively. There were significant relationships between both total or DTPA-extractable
Pb concentrations and selected physico-chemical properties of soil. According to enrichment factor (EF) values calculated
from the total Pb concentrations, 11.3% of the study area (225 km2) was enriched with Pb in high level, but 77% of the area was in significant enrichment level with Pb. The average total and
DTPA-extractable Pb concentrations increased as 11 and 13%, respectively in comparison with the results of 1998. 相似文献
6.
Determination of lead, cadmium and copper in roadside soil and plants in Elazig, Turkey 总被引:1,自引:0,他引:1
The concentrations of lead, cadmium and copper in roadside soil and plants in Elazig, Turkey were investigated. Soil samples
were collected at distances of 0, 25 and 50 m from the roadside. The concentrations of lead, cadmium and copper were measured
by Flame Atomic Absorption Spectrophotometry (FAAS). A slotted tube atom trap (STAT) was used to increase the sensitivity
of lead and cadmium in FAAS. Lead concentrations in soil samples varied from 1.3 to 45 mg kg−1 while mean lead levels in plants ranged from120 ng g−1 for grape in point-4 to 866 ng g−1 for apple leaves in point-2. Lead analyses showed that there was a considerable contamination in both soil and plants affected
from traffic intensity. Overall level of Cd in soil samples lies between 78 and 527 ng/g while cadmium concentration in different
vegetations varied in the range of 0.8–98.0 ng g−1. Concentrations of copper in soil and plant samples were found in the range of 11.1–27.9 mg kg−1 for soil and 0.8–5.6 mg kg−1 for plants. Standard reference material (SRM) was used to find the accuracy of the results of soil analyses. 相似文献
7.
In a comprehensive program of environmental radioactivity survey in South Caspian region,137Cs inventories in soil has been measured at more than 50 sites in the Iranian northern province of Guilan. This has been the
first wide-range survey of soil radionuclide inventories in the narrow band sensitive ecosystem of south Caspian shore. Radioactivity
measurements were carried out using HPGe gamma-spectrometry system. The activity concentration of 137Cs in surface soil exhibits a mean value of 17.6 ± 9.4 Bq kg−1, with a range of 2.3–41.7 Bq kg−1. In many sites, split-level sampling method has been applied down to a depth of 20 cm. There were found generally two profiles.
Most profiles exhibit a negative exponential distribution, while others revealed a clear subsurface peak in 5–10-cm layer.
Cesium deposition in the study area has been estimated to be in the range of 0.38–2.9 kBq m−2 with a mean value of 1.7 kBq m−2. Distribution patterns of 137Cs concentration levels and deposition values have been estimated using Kriging interpolation method. Observed hotspots in
deposition pattern coincide with areas of higher precipitation. 相似文献
8.
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
9.
This is the first comprehensive study of sources of variation in metal concentrations within the whole tissues of a shallow burrowing, filter-feeding intertidal clam, Austrovenus stutchburyi. Samples were collected from 12 sites in April, August, November and February in 1993–1994 in the vicinity of Otago Harbour and Peninsula, New Zealand. Total tissue trace metal concentrations (μg g−1 dry weight) were measured in individual animals for the essential metals : Mn, Cu, Zn, Ni and the non-essential Cr using trace-metal clean acid-digestion and ICP-OAES techniques. Average metal concentrations were 3–60 μg g−1 for Cu, 40–118 μg g−1 for Zn, 2–12 μg g−1 for Mn, 5–35 μg g−1 for Ni and 1–44 μg g−1 for Cr. These levels decreased with body weight and differed amongst sites except for Cr in February (mid-summer). Highest concentrations occurred at sites close to a city (Dunedin) and within the central harbour region although the Cu, Zn, Ni and Cr concentrations did not correlate with the environmental gradient or season. At one coastal site, samples of both the blue mussel Mytilus galloprovincialis and cockles gave similar trends in trace metal levels. These results suggest that the cockle could be a useful trace metal biomonitor within NZ estuaries. 相似文献
10.
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
11.
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
12.
Presence of pesticide residues was studied in rain water during 2002 employing multi residue analysis method by gas liquid
chromatography equipped with ECD and NPD detectors and capillary columns. The presence of pesticide residues in surface aquatic
system triggered the investigation of the presence of pesticides in rain water. A total of 13 pesticides were detected in
rain water samples. Among the different groups of pesticides, organochlorines were present in the range of 0.041–7.060 ppb
with maximum concentration of p,p’-DDT up to 7.060 μg l−1. Synthetic pyrethroids were present ranging from 0.100 to 1.000 μg l−1 and organophosphates in the range of 0.050–4.000 μg l−1 showing maximum contamination with cypermethrin (1.000 μg l−1) and monocrotophos (4.000 μg l−1) of the respective groups. Almost 80% samples showed the residues above MRL of 0.5 ppb fixed for multi residues and on the
basis of single pesticide, 16–50% samples contained residues above the MRL value of 0.1 ppb. 相似文献
13.
Ashraf W Seddigi Z Abulkibash A Khalid M 《Environmental monitoring and assessment》2006,117(1-3):271-279
In the present paper, seven heavy metals (Pb, Cd, Ni, Cu, Zn, Cr and Fe) in canned salmon, sardine and tuna fish were determined
by using atomic absorption spectroscopy. Cadmium and lead levels were determined by graphite tube AAS whereas Ni, Cu, Cr and
Fe were determined by flame AAS. Analytical results were validated by spiking the samples with various concentrations of these
metals for recovery. The metal contents, expressed in μg/g, wet weight, varied depending upon the specie studied. The levels
of Pb ranged from 0.03–1.20 μg-g−1 with an average of 0.313 μg-g−1 for salmon; 0.03–0.51 μg-g−1 with an average of 0.233 μg-g−1 for tuna and 0.13–1.97 μg-g−1 with an average of 0.835 μg-g−1 for sardines. The levels of Cd ranged from 0.02–0.38 μg-g−1 with an average of 0.161 μg-g−1 for salmon; 0.07–0.64 μg-g−1 with an average of 0.227 μg-g−1 for tuna and 0.010–0.690 μg-g−1 with an average of 0.183 μg-g−1 for sardines. Comparative evaluation of these metals in three varieties of fish showed that average concentration of lead
in sardines is about 4 times and Ni about 3 times higher as compared to tuna. Generally, the levels of these metals follow
the order sardine > salmon > tuna. The data generated in the present study compared well with the similar studies carried
out in different parts of the world. The results indicate that canned fish, in general and tuna in particular, have concentrations
within permissible limits of WHO/FAO levels for these heavy metals. Therefore, their contribution to the total body burden
of these metals can be considered as negligibly small. 相似文献
14.
Manchar Lake is the largest natural freshwater lake in Pakistan. The Lake has received less fresh water in past few years.
In addition, drainage water is being discharged in the Lake through Main Nara Valley Drain (MNVD) since many years. Consequently,
concern has grown regarding the water quality of the Lake. The aim of this study was to assess the water quality of Manchar
Lake and MNVD and the objectives were to determine physiochemical properties and the concentrations of common cations and
anions as well as seven trace metals i.e. Cu, Ni, Zn, Co, Fe, Pb and Cd. The concentration of the trace metals were determined
by simultaneous preconcentration and solvent extraction using flame atomic absorption spectrometer. Results of physicochemical
parameters of Manchar Lake water samples showed mean pH 8.4 (±0.2), conductivity 2,310.3 (±581.3) μS cm−1 and hardness (as CaCO3) 213.1 (±62.3) mg l−1. Mean concentrations of cations and anions were Na 521.5 (±49.7), Cl− 413.6 (±225.7), Ca 70.7 (±12.9), Mg 56.2 (±28.9), K 17.6 (±6.5), 0.34 (±0.2) and 0.02 (±0.01) mg l−1. Mean concentrations of trace metals were Zn 15.7 (±1), Fe 12 (±3.5), Pb 9 (±2.7), Cu 8.9 (±7.7), Ni 4.3 (±3.4), Co 4 (±3.4)
and Cd 1.1 (±1) μg l−1. MNVD water samples showed mean pH 8.9 (±0.8), conductivity 1,735.7 (±567.8) μS cm−1 and hardness (as CaCO3) 184.8 (±32.4) mg l−1. In MNWD, the mean concentrations of cations and anions were Na 482.7 (±11.7), Cl− 395.7 (±271.5), Ca 79.1 (±23.5), Mg 54.2 (±28.1), K 26.2 (±21.3), NO−3 0.5 (±0.3) and 0.1 (±0.1) mg l−1. Mean concentrations of trace metals observed in MNWD water were Fe 14.9(±3.5), Cd 8.3 (±9.4), Pb 6.9 (±2.4), Cu 6.6 (±3.1),
Zn 6.2 (±1.8), Co 4.5 (±2.7), and Ni 3.5 (±2.9) μg l−1. The pH of both Manchar Lake and MNVD waters and concentration of Pb in Manchar Lake and concentration of Cd in MNVD water
were higher than the World Health Organisation’s guideline values for the drinking water quality. The water quality of Manchar
Lake was found degraded. 相似文献
15.
A five-stage sequential extraction procedure was used to fractionate heavy metals (Cd, Cu, Pb, Cr, Zn, Fe, Mn, Ni, Co, As,
V and Ba) in a biosludge from the biological wastewater treatment plant of Stora Enso Oyj Veitsiluoto Mills at Kemi, Northern
Finland, into the following fractions: (1) water-soluble fraction, (2) exchangeable fraction, (3) easily reduced fraction,
(4) oxidizable fraction, and (5) residual fraction. The biosludge investigated in this study is a combination of sludge from
the primary and secondary clarifiers at the biological wastewater treatment plant. Extraction stages (2)–(4) follow the protocol
proposed by the Measurements and Testing Program (formerly BCR Programme) of the European Commission, which is based on acetic
acid extraction (stage 2), hydroxylamine hydrochloride extraction (stage 3), and hydrogen peroxide digestion following the
ammonium acetate extraction (stage 4). The residual fraction (stage 5) was based on digestion of the residue from stage 4
in a mixture of HF + HNO3 + HCl. Although metals were extractable in all fractions, the highest concentrations of most of the metals occurred in the
residual fraction. From the environmental point of view, it was notable that the total heavy metal concentrations in the biosludge
did not exceed the maximal allowable heavy metal concentrations for sewage sludge used in agriculture, set on the basis of
environmental protection of soil by European Union Directive 86/278/EEC, and by the Finnish legislation. The Ca (98.6 g kg−1; dry weight) and Mg (2.2 g kg−1; dry weight) concentrations in the biosludge were 62 and 11 times higher than the typical values of 1.6 and of 0.2 g kg−1 (dry weight), respectively, in arable land in Central Finland. The biosludge had a slightly alkaline pH (∼8.30), a high loss-on-ignition
value (∼78%) and a liming effect of 10.3% expressed as Ca equivalents (dry weight). This indicates its potential as a soil
conditioner and improvement agent, as well as a pH buffer. 相似文献
16.
Estimation of Polish cigarettes contamination with cadmium and lead, and exposure to these metals via smoking 总被引:2,自引:0,他引:2
Galazyn-Sidorczuk M Brzóska MM Moniuszko-Jakoniuk J 《Environmental monitoring and assessment》2008,137(1-3):481-493
To estimate exposure to cadmium (Cd) and lead (Pb) through cigarette smoking, the concentrations of both metals in the blood
or/and urine of smokers (20 cigarettes or more per day for 10 years or longer) and their non-smoking counterparts inhabiting
an environmentally unpolluted area (Bialystok, Poland) were evaluated, as well as Cd and Pb contents in the cigarette brands
(produced in Poland) smoked by the participants, including intact cigarettes, pre-smoking (tobacco, paper and filter) and
post-smoking (butt, ash and smoke) cigarette components. Blood and urinary Cd concentrations in the smokers have been already
reported by us to be 2–4 times higher than in the non-smokers (Galażyn-Sidorczuk et al. Polish Journal of Environmental Studies,
13 (Suppl.1):91–95, 2004). All the other measurements are the subject of the present paper. Pb concentration in the blood of the cigarette smokers
(52.12 ± 15.51 μg l−1) was higher by 29% than in the non-smokers (40.42 ± 11.19 μg l−1). The mean Cd and Pb contents in the cigarettes were 0.6801 ± 0.1765 and 0.6853 ± 0.0746 μg per cigarette, respectively.
Under cigarette burning, performed using a machine for self-acting burning, on average 33% of Cd and 11% of Pb present in
the whole cigarette was released into the smoke. For Cd, unlike Pb, there was a high positive correlation between the metal
content in cigarettes and tobacco and its release into the smoke. Moreover, the subjects smoking cigarettes containing the
highest Cd amount had higher blood Cd concentration than smokers of other cigarette brands. The results give clear evidence
that in the case of inhabitants of areas unpolluted with Cd and Pb habitual cigarette smoking, due to tobacco contamination,
creates a serious source of chronic exposure to these metals, especially to Cd. 相似文献
17.
Dissipation behaviour of endosulfan and dichlorvos in/on cauliflower, variety Snowball-16, was studied during rabi season
(Sep.–March) 2003–2004. Endosulfan and dichlorvos were sprayed @ 350 and 110g a.i. with 115 g a.i., respectively, 80 days
after transplanting. Samples were taken at the interval of 0 (1h after spray), 3, 5, 7, and 10 days after spray (DAS) in triplicate
and residues were estimated on GC-ECD system equipped with capillary column. The initial deposits of 3.452 and 0.295μgg−1 of endosulfan and dichlorvos dissipated to 0.084 (97.56%) and 0.009 (96.95%), respectively after 10 DAS. Residues of endosulfan
reached below maximum residue limit of 2μgg−1 one day after spray and of dichlorvos were below MRL value of 0.5μgg−1 even on 0 day. Dissipation pattern followed first order kinetics for both the insecticides with half life periods of 1.81
and 2.08 days for endosulfan and dichlorvos, respectively. 相似文献
18.
Results of systematic, long-term measurements of 137Cs activities in wheat for the period 1965–2003 are summarized. Radiocaesum fallout activities affect wheat activity concentrations, the coefficient of correlation being 0.91. In the observed period, the highest activity of 137Cs deposited by fallout, 6321 Bq m−2, was recorded in 1986, i.e., in the year of Chernobyl accident, causing peak 137Cs activity concentration in wheat of 38.0 ± 13.0 Bq kg−1. After the Chernobyl nuclear accident the 134Cs:137Cs activity ratio in wheat was ≈0.5, and did not differ from the value found in other environmental samples. The transfer coefficient from 137Cs fallout deposition to wheat was calculated to be 8.6 × 10−3 Bq y kg−1 per Bq m−2, indicating the low transfer of radiocaesium from fallout to wheat. The upper limit for the collective effective dose for the Croatian population due to 137Cs and 134Cs ingestion by wheat and wheat products consumption for period 1965–2003 was estimated to be 665 person-Sv, the upper limit for the annual collective effective dose in 2003 being only about 0.061 person-Sv. 相似文献
19.
Wetherbee GA Gay DA Brunette RC Sweet CW 《Environmental monitoring and assessment》2007,131(1-3):49-69
The National Atmospheric Deposition Program/Mercury Deposition Network (MDN) provides long-term, quality-assured records of
mercury in wet deposition in the USA and Canada. Interpretation of spatial and temporal trends in the MDN data requires quantification
of the variability of the MDN measurements. Variability is quantified for MDN data from collocated samplers at MDN sites in
two states, one in Illinois and one in Washington. Median absolute differences in the collocated sampler data for total mercury
concentration are approximately 11% of the median mercury concentration for all valid 1999–2004 MDN data. Median absolute
differences are between 3.0% and 14% of the median MDN value for collector catch (sample volume) and between 6.0% and 15%
of the median MDN value for mercury wet deposition. The overall measurement errors are sufficiently low to resolve between
NADP/MDN measurements by ±2 ng·l−1 and ±2 μg·m−2·year−1, which are the contour intervals used to display the data on NADP isopleths maps for concentration and deposition, respectively. 相似文献
20.
A sensitive spectrophotometric method has been developed for determination of ametryn in agricultural samples. The proposed
method was based on reaction with pyridine and further coupling with sulfanilic acid to form a colored product. The absorbance
was measured at 400 nm with a molar absorptivity of 2.1 × 105 L mol−1 cm−1. The method shows a linear range from 0.2–20 μg mL−1 with limit of detection and limit of quantification 0.16 and 0.54 μg mL−1, respectively. The method has been successfully applied to the determination of ametryn in sugarcane juice and commercial
formulations after separation of ametryn from triazine herbicides based on solvent extraction. Recovery values were found
to be in the range of 96.0 ± 0.2% to 98.4 ± 0.1%. 相似文献