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1.
It is well documented that synthetic chlorinated hydrocarbon residues are widespread through the oceanic ecosystem. The Adriatic Sea, as semi-enclosed body of water, is of special interest for an evaluation of the entry, extent and fate of the pollution by chlorinated hydrocarbons. Sediments samples were collected from 1976 to 1990 at seven areas and over forty stations located on the eastern Yugoslav coastal waters. Concentrations of chlorinated insecticides and polychlorinated biphenyls in surface sediment samples ranged from <0.1 to 93.9 for DDTs and from <0.5 to 294 μg kg?1 for PCBs on dry weight basis. It is very important to stress that all these samples were analyzed from a single analytical group (mostly by the same analyst), using a uniform methodology. Total DDT and PCB concentration do not exhibit Gausian distribution in the investigated area and collecting period, so it is necessary to be very careful in interpreting the concentration data using parametric statistics. Very often, the pollutant levels in sediment samples differ significantly in samples collected at the same time at nearby stations.  相似文献   

2.
In a rural community (Stephanskirchen, Southern Germany) situated near a waste incineration plant six A horizons were sampled to determine 14 polychlorinated biphenyls (PCBs) in bulk soil and particle size separates (clay, silt, fine and coarse sand) and to test the suitability of alkaline saponification for PCB extraction. The PCB concentrations were higher in alkaline saponification extracts than in Soxhlet extracts. However, the extraction efficiency of up to fourfold chlorinated PCBs was lower and more than sevenfold chlorinated PCBs were destroyed. Nevertheless, alkaline saponification was suitable to determine the indicator congeners 28, 52, 101, 138, 152, and 180. The sum of the PCB concentrations ranged from 8.4 to 59.5 μg kg?1 which was as high as in soils of big cities. However, the concentrations did not reach the threshold value for agricultural purposes of 200 μg kg?1 as proposed in literature for the sum of the six indicator congeners. The hexachlorinated PCBs 138 and 153 were the most abundant (together > 50% in all samples) whereas PCB 1 could not be detected in any sample. On the average, PCB concentrations increased as particle size decreased. When normalized to Corg, however, the fine sand fraction had the highest PCB concentrations. A slight decrease of lower chlorinated PCBs as particle size decreased indicated an increasing state of degradation. The PCB compositions in the emissions of a comparable waste incineration plant (Bamberg, Bavaria) and in Stephanskirchen soils differed markedly. Therefore, we did not get any indications that waste incineration was a main source of PCBs in the examined soils. Instead, higher chlorinated technical PCB mixtures such as Clophen A 60 or Aroclor 1260 may be the most important sources.  相似文献   

3.
Arsenic (As) poisoning of groundwater in Bangladesh has become a major environmental and health issue. The extensive use of groundwater in irrigation of rice has resulted in elevated As in soils and crops. A study was undertaken to determine As concentrations in groundwater, soils, and crops in 16 districts of southwestern Bangladesh. Groundwater samples were collected from shallow-tube and hand-tube wells (STW and HTW) used for irrigation and drinking water. Soil and rice plants were sampled from the command area of the tube wells. Arsenic concentrations were determined using an atomic absorption spectrometer equipped with flow injection hydride generator. Groundwater samples contained <10 to 552 μg As L?1. Arsenic concentrations in 59% of STW samples exceeded 50 μg As L?1, the national standard for As in drinking water. Unlike groundwater, most of the surface water samples contained <10 μg As L?1. Concentrations of As in the soils from the command area of the tube wells ranged from 4.5 to 68 mg kg?1. More than 85% of the soils contained <20 mg As kg?1. The mean As concentration in the rice grain samples was 0.23 mg kg?1, which is much less than the maximum food hygiene standard. A positive relationship was observed between groundwater and soil As, implying that soil As level increases as a result of irrigation with contaminated water. However, irrigation water As did not show any relation with rice grain As. The findings suggest that surface water bodies are a safe source of irrigation water in the As-contaminated areas.  相似文献   

4.
Air pollution and atmospheric deposition by PCBs and organochlorine pesticides (isomers of HCH and p,p′-DDE) were studied at Paris from January 1986 to June 1987. The deposition measured as total (wet plus dry) was also followed during 1986 on two suburban and two rural sites. The distribution of the pollutants between the vapor phase and aerosols was evaluated by sampling air through a glass microfiber filter connected to a Tenax resin cartridge. The study shows that in the atmosphere as in waters of the catchment area of the Seine river, PCBs are the main organochlorine pollutants. Pollution by OCL is of the same order as the one described in literature (mean γ-HCH concentration 1.4 ng m?3) while PCB concentrations in the atmosphere are equal to or higher than those observed in USA and Europe (range 5 to 44 ng m?3). On the average, 93% of the PCBs are in the vapor phase with a composition approximating Aroclor 1242. In aerosols and precipitations the composition is closely related to Aroclor 1254. The total fallout for 1986 was 40 μg m?2 for PCBs and 20 μg m?2 for γ-HCH, rainfall being 611 mm.  相似文献   

5.
We determined heavy metal, polycyclic aromatic hydrocarbon (PAH), and polychlorinated biphenyl (PCB) concentrations in 18 topsoils of Uberlândia (420,000 inhabitants, Brazil) and in 3 rural topsoils. Concentrations of Al (11—124 g kg—1) and Fe (13—109 g kg—1) are large because of desilification. Concentrations of Cd (0.1—0.5 mg kg—1), Cr (13—72), Cu (6—154), Mn (28—974), Ni (4—29), Pb (3—26), Zn (4—107), the sum of 20 PAHs (=Σ20PAHs:7—390 μg kg—1), and the sum of 14 PCBs (=Σ14PCBs:0.05—1.25) are comparable to or below background concentrations in temperate soils except for Cu at two sites. More than 67% of the metals are strongly bound in Fe oxides and silicates; metals are more bioavailable in the urban than in the rural soils. The most abundant PAHs in the urban soils, on average, are naphthalene (19.0 ± 13.4% of Σ20PAHs) and the benzo(b+j+k)fluoranthenes (11.4 ± 6.7%); the most abundant PCBs are nos. 138 (23.3 ± 11.0% of Σ14PCBs) and 153 (14.3 ± 6.4%). The rural soils contain larger percentages of low molecular PAHs and up to tetra‒chlorinated PCBs than the urban soils. The different pollutant concentrations and patterns in the studied tropical compared with many temperate soils indicate different sources and fate.  相似文献   

6.

Purpose

Arid and hyper-arid zones worldwide are reservoirs of chemical compounds, among them are various trace elements. With climate change, abnormal precipitation is occurring in arid and hyper-arid mountainous zones, which in turn is increasing the displacement of trace elements from mountainous to populated areas. The objective of this study was to evaluate trace element displacement of a sediment-laden flood in the Copiapó River Basin on March 24–25, 2015.

Materials and methods

Sixty topsoil samples were taken from 20 agricultural fields. Soil organic matter content, pH, electrical conductivity, and particle size were determined according to accepted procedures in Chile. Samples were acid-digested to determine total Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se, and Zn content by flame atomic absorption spectroscopy. Hydride generation AAS was used for As and Se determination, and Hg was quantified by cold vapor AAS. Detection limits were 0.2, 0.05, 0.1, and 5.0 mg kg?1 for Cd, Hg, Se, and Mo, respectively. Correlation and principal component analyses were made, and theoretical distribution functions were fitted to each element.

Results and discussion

Metal concentration showed a strong correlation between SOM and particle size, explaining the first component from the principal component analysis. All trace elements correlated well between each other except for Mo and Se. Mo values were consistently below detection levels (<5.0 mg kg?1). Expected values for the elements were (95% of probability): 13–37 g Al kg?1, 10–50 mg As kg?1, <0.2–0.6 mg Cd kg?1, 13–25 mg Cr kg?1, 27–281 mg Cu kg?1, 27–40 g Fe kg?1, <0.05–6.5 mg Hg kg?1, 516–1.080 mg Mn kg?1, 7–24 mg Ni kg?1, 13–50 mg Pb kg?1, 0.2–0.6 mg Se kg?1, and 61–172 mg Zn kg?1. Concentrations of As, Cu, and Hg were consistently above national standards.

Conclusions

The authors conclude that the trace element contents in sediments deposited by the event are within expected values based on soil data in Chile.
  相似文献   

7.
Water quality of Lake Okeechobee has been a major environmental concern for many years. Transport of dissolved organic matter (DOM) in runoff water from watershed is critical to the increased inputs of nutrients (N and P) and metals (Cu and Zn). In this study, 124 soil samples were collected with varying soil types, land uses, and soil depths in Lake Okeechobee watershed and analyzed for water-extractable C, N, P, and metals to examine the relationship between dissolved organic carbon (DOC) and water soluble nutrients (N and P) and metals in the soils. DOC in the soils was in 27.64?C400 mg kg?1 (69.30 mg kg?1 in average) and varied with soil types, land uses, and soil depth. The highest water-extractable DOC was found in soils collected in sugar cane and field crops (277 and 244 mg kg?1 in average, respectively). Water soluble concentrations of N and P were in the range of 6.46?C129 and 0.02?C60.79 mg kg?1, respectively. The ratios of water-extractable C/N and C/P in soils were in 0.68?C12.52 (3.23 in average) and 3.19?C2,329 (216 in average), and varied with land uses. The lowest water-extractable C/N was observed in the soils from dairy (1.66), resident (1.79), and coniferous forest (4.49), whereas the lowest water-extractable C/P was with the land uses of dairy (13.1) and citrus (33.7). Therefore, N and P in the soils under these land uses may have high availability and leaching potential. The concentrations of water soluble Co, Cr, Cu, Ni, and Zn were in the ranges of?<?method detection limit (MDL)?C0.33, <MDL?C0.53, 0.04?C2.42, <MDL?C0.71, and 0.09?C1.13 mg kg?1, with corresponding mean values of 0.02, 0.01, 0.50, 0.07, and 0.37 mg kg?1, respectively. The highest water soluble Co (0.10 mg kg?1), Cr (0.26 mg kg?1), Ni (0.31 mg kg?1), and Zn (0.80 mg kg?1) were observed in soils under the land use of sugar cane, whereas the highest Cu (1.50 mg kg?1) was with field crop. The concentration of DOC was positively correlated with total organic carbon (TOC) (P <0.01), water soluble N (P <0.01), electrical conductivity (EC, P <0.01), and water soluble Co, Cr, Ni, and Zn (P <0.01), and Cu (P <0.05), whereas water soluble N was positively correlated with water soluble P, Cu, and Zn (P <0.01) in soils. These results indicate that the transport of DOC from land to water bodies may correlate with the loss of macro-nutrients (N, P), micro-nutrients (Cu, Zn, and Ni), and contaminants (Cr and Co) as well.  相似文献   

8.
Abstract

Water extraction of trace elements can simulate the concentration of elements in the soil solution from where the plant takes up the elements. The objective of this investigation was to determine the water extractable concentration of seven trace elements (Fe, Mn, Ni, Co, Mo, Pb and Cd) and to assess their relationship with soil properties of the Danube basin in Croatia. Soil samples from the surface layer (0–25 cm) of 74 sites, having different land uses (forest and agricultural land), were collected. Samples were analysed for total and water extractable trace elements as well as for pH, DOC, SOC and CEC. The concentrations of water extractable fraction of trace elements were on average: 20.14 mg kg?1 for Fe, 3.61 mg kg?1 for Mn, 0.07 mg kg?1 for Ni, 0.016 mg kg?1 for Co, 0.01 mg kg?1 for Mo, 0.01 mg kg?1 for Pb and 0.0009 mg kg?1 for Cd. Soil properties were in the following range: pH 4.3–8 (Avg: 6.35), DOC 6.1–73 mg l?1 (Avg: 26 mg l?1), CEC 1.3–24 cmol kg?1 (Avg: 9 cmol kg?1) and SOC 0.5–5% (Avg: 1.7%). The concentration of water extractable fraction of trace elements was significantly correlated with pH (p <0.001), DOC (p <0.001 – p <0.05) and CEC (p <0.001) but their relationship with total content of trace element and SOC was rather weak, suggesting that total metal alone cannot be an indicator of toxicity or deficiency. Results show that pH, DOC and CEC are important soil quality parameters taking part in the solubility control of trace metals in the soil rather than their total concentration. The difference between land uses has been observed as well, suggesting that a change in land use can cause a change in trace element solubility.  相似文献   

9.
Multiple element analyses were carried out to investigate variation in element concentrations in barley grains of 336 genotypes. Of 13 elements analyzed, Ba ranged from 0.2 to 8.9?mg kg?1, Ca from 186.4 to 977.5?mg kg?1, Cu from 1.5 to 9.8?mg kg?1, K from 353.2 to 7721.5?mg kg?1, Mg from 1049.8 to 2024.2?mg kg?1, Mn from 8.1 to 22.9?mg kg?1, Na from 55.9 to 627.9?mg kg?1, P from 2272.9 to 5428.8?mg kg?1, S from 880.7 to 1898.0?mg kg?1, Si from 19.1 to 663.2?mg kg?1, and Sr from 0.35 to 2.62?mg kg?1 in the barley grain. The least square means showed high Zn, Fe, Mg, P, and S concentration in AM-64 and AM-228 genotypes. The principal component analysis of element concentration showed four PCs explained 64.3% total variance. Strong positive correlations (p?<?0.001) of Fe-Mn, Fe-S, S-Mn, Zn-P, Zn-Mg, Mg-P, Mg-Mn, and Ca-Sr were found. The identification barley genotypes that showed high elements concentration furnish valuable genetic resources for biofortification in future.  相似文献   

10.

Purpose

River ecosystems are under pressure from several different stressors. Among these, inorganic pollutants contribute to multiple stressor situations and the overall degradation of the ecological status of the aquatic environments. The main sources of pollution include different industrial activities, untreated effluents from municipal waste waters and intensive agriculture. In the present study, water, suspended particulate matter (SPM) and sediments of the Sava River were studied in order to assess the pollution status of this river system.

Materials and methods

Sampling was performed during the first sampling campaign of the EU 7th FW funded GLOBAQUA project in September 2014, at 18 selected sampling sites along the Sava River. In 2014, floods predominated from spring to fall. Water samples were collected to determine the total element concentrations, the dissolved (0.45 μm) fraction and element concentrations in SPM. In order to assure comparative results with other river basins, the fraction below 63 μm was analysed in sediments. The extent of pollution was estimated by determination of the total element concentrations and by the identification of the most hazardous highly mobile element fractions (extraction 0.11 mol L?1 acetic acid) and anthropogenic inputs of elements to sediments (normalization to aluminium (Al) concentration). Concentrations of selected elements were determined by inductively coupled plasma mass spectrometry (ICP-MS).

Results and discussion

Since during sampling campaign the water level was extremely high, water samples contained high amounts of SPM (in general between 80 and 100 mg L?1). The data of chemical analysis revealed that concentrations of elements in water, SPM and sediments in general increase along the Sava River from its origin to the confluence with the Danube River. Elevated concentrations of chromium (Cr) and nickel (Ni) in SPM and sediments were observed at industrially exposed sites. Concentrations of Cr and Ni in sediments were up to 320 and 250 mg kg?1, respectively. Nevertheless, these elements were present in sparingly soluble forms and hence did not represent an environmental threat. Phosphorus (P) was found in elevated concentrations (up to 1500 mg kg?1) at regions with intensive agricultural activities and cities with dense population.

Conclusions

With respect to element concentrations, the pollution of the Sava River is similar to other moderately polluted European rivers. The data from the present study are beneficial for the water management authorities and can contribute to sustainable utilization, management and protection of the Sava River water resources.
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11.
In a screen-house study, the effects of artificially contaminating the soil with lead (Pb) at levels ranging from 0 to 1500 mg kg?1 soil on the growth and uptake of Pb and micronutrients by Indian mustard [Brassica juncea (L.) Czern.] grown on a loamy sand soil (Typic Ustorthent) were investigated. The crop was grown for 60 days with adequate basal fertilization of nitrogen, phosphorus, and potassium, and dry matter was recorded. The plants were analyzed for total Pb and micronutrients, and the soil was analyzed for diethylenetriaminepentaacetic acid (DTPA)-extractable Pb. The DTPA-extractable Pb measured before sowing of Indian mustard increased consistently and significantly with increase in rates of Pb application to soil. It increased from 0.65 mg kg?1 in the control to 199.8 mg kg?1 in soil treated with 1500 mg Pb kg?1 soil. Significant reduction in the dry-matter yield of Indian mustard occurred with Pb applications of 500 mg kg?1 soil and greater. The concentration as well as uptake of Pb by Indian mustard increased significantly over control at all rates of its application. It increased from 9.4 μg pot?1 in the control to 220.6 μg pot?1 at Pb application of 1500 mg kg?1 soil. Applications of Pb to the soil decreased the concentration of micronutrients in plants, but a significant reduction occurred only for iron at rates greater than 500 mg Pb kg?1 soil. However, the uptake of iron, manganese, and copper registered a significant decline at Pb application of 500 mg kg?1 and greater and that of zinc at 750 mg kg?1 and greater. In a Typic Ustorthent soil, a DTPA-extractable Pb level of 59.5 mg kg?1 and plant content of 44.2 μg Pb g?1 dry matter was found to be the upper threshold levels of Pb for Indian mustard. This study suggests that once the soil is contaminated by Pb, it remains available in the soil for a long time, and such soils, if ingested with food crops, may be a significant source of Pb toxicity to both humans and grazing animals.  相似文献   

12.
This paper presents the findings of initial investigation of the role of Spartina alterniora Loisel. in the movement of chlorinated hydrocarbons. 14C-polychlorinated biphenyls and technical Aroclor® 1254 were used for the determinations. The findings demonstrate that Spartina accumulates 14C-radioactivity from sand and organic mud soil systems treated with 14C-PCB's. These findings also demonstrate that this plant has the capacity to accumulate 14C-radioactivity to levels elevated above that in the treated soil. Other experiments with Aroclor® 1254 demonstrate that cogeners of Aroclor® 1254 are present in Spartina stem and root extracts. These experiments also suggest that the chlorinated hydrocarbon uptake process is modulated by the plant and that this results in selective cogener uptake. The selectivity appears to be for the lesser chlorinated components of the commercial mixture. Overall, this study suggests that Spartina may act as an initial vector for mobilization of sediment bound chlorinated hydrocarbons to the estuarine food chain.  相似文献   

13.
Sample preparation affects the results of the determination of persistent organic pollutant (POP) concentrations in soils. We compared the extraction results of POPs from air‐ and freeze‐dried with field‐fresh samples. We determined the concentrations of 21 polycyclic aromatic hydrocarbons (PAHs) and 14 polychlorinated biphenyls (PCBs) in 35 horizons of forest soils (Lithosols and Cambisols) along a deposition gradient caused by a chemical factory in Strá?ske (eastern Slovakia). The organic C (Corg) concentrations of the studied samples ranged 14‐477 g kg‐1, the sum of 21 PAH (Σ 21PAHs) concentrations 53‐6870 μg kg‐1, and that of 14 PCBs (Σ 14PCBs) 0.12 96 μg kg‐1. The benzofluoranthenes were the most abundant PAHs, and the hexa‐chlorinated PCBs 138 and 153 were the most abundant PCBs. The deposition gradient was reflected by decreasing PAH and PCB storages in the organic layer with increasing distance from the chemical factory (Σ 21PAHs: 82‐238, Σ 14PCBs: 0.34‐2.3 g ha‐1). The PAH concentrations in air‐ and freeze‐dried samples were consistently lower than those in field‐fresh extracted samples. For naphthalene, this was mainly attributable to volatilization losses during drying. Naphthalene losses decreased with increasing Corg concentrations. For all other PAHs, drying reduced the extractability; the latter was correlated with the water content of the samples. The differences in most PCB concentrations among the sample preparation methods were small (within the determination error of ±15 %) and inconsistent. However, PCBs 8, 28, 52, and 209 had markedly higher concentrations in dried than in fieldfresh extracted samples. The increased recovery of low‐chlorinated PCBs in dried samples may be explained by redistribution of PCBs from higher to lower contaminated samples via the drying room atmosphere because there were no PCBs in analytical blanks. This assumption is supported by a close correlation between the octanol‐air distribution coefficient and the up to hexa‐chlorinated PCB concentrations (normalized to those in field‐fresh extracted samples) in air‐ (r = ‐0.90) and freeze‐dried (r = ‐0.86) samples. Our study shows that each sample preparation method has its specific advantages and disadvantages. Sample drying results in a standardization to a well‐defined water content and facilitates homogenization; therefore it increases the reproducibility of POP determinations. Extraction of field‐fresh samples reduces volatilization losses and contamination risks.  相似文献   

14.
A gas chromatographic-electron capture detection method for determining the concentration of polychlorinated biphenyls (PCBs) as Aroclor 1254 (AR 1254) in serum was evaluated through a 2-phase collaborative study. In Phase I, each collaborator's lot of Woelm silica gel (70-150 mesh) was evaluated for elution and recovery of AR 1254, which had been added in vitro at 25 ng/mL to a serum extract. In Phase II, each collaborator analyzed a series of bovine serum samples that contained the following: (1) in vitro-spiked AR 1254; (2) in vivo AR 1254 and 8 in vitro-spiked chlorinated hydrocarbons; (3) in vivo AR 1254 only; (4) 8 in vitro-spiked chlorinated hydrocarbons only; and (5) neither AR 1254 nor chlorinated hydrocarbons above the detection limit of the method. In Phase I, the average recovery of AR 1254 from silica gel for the 6 collaborators was 87.9 +/- 15.44% (mean +/- 1 SD; N = 18; range = 52.3-105.8%). In Phase II, the analysis of in vitro spikes of AR 1254 in serum at 8.58, 16.8, 41.8, and 84.3 ppb gave mean (means) interlaboratory recoveries of 89.0, 83.3, 79.4, and 76.9%, respectively, with within-laboratory (repeatability) relative standard deviations (RSDr) of 18.8, 20.5, 10.2, and 14.1%, respectively, and among-laboratory (reproducibility) relative standard deviations (RSDR) of 21.5, 21.1, 14.6, and 20.8%, respectively. The determination of in vivo AR 1254 in samples containing approximately 10, 25, 50, and 100 ng/mL of AR 1254 resulted in interlaboratory means of 10, 22, 39, and 79 ng/mL, respectively, with RSDr = 6.7, 9.7, 6.4, and 5.8%, respectively, and RSDR = 20.6, 16.0, 10.9, and 10.3%, respectively. The precision of the method for incurred AR 1254 showed a maximum RSDr of less than 10% and a maximum RSDR of less than 21% for a concentration range of 10-100 ng/mL. The accuracy of the method as demonstrated by the mean recovery of in vitro-spiked AR 1254 over a concentration range of 8.58-843 ng/mL was 82.2%. The method has been approved interim official first action.  相似文献   

15.
Sediment cores were obtained from several locations in the Calcasieu River/Lake Complex (Lousiana), including Calcasieu Lake, Calcasieu River, two bayou tributaries, and Lake Charles, during the period from November 1983 to November 1985. The cores were analyzed for Cu, Zn, Cr, and Pb. The approximate sedimentation rate and a core chronology were determined by the use of 137Cs and 210Pb. The increase in metal concentrations after 1933, particularly along Bayou d'Inde where most industries are located, points to anthropogenic input of these metals to the system. The fact that metal concentrations tend to merge to a common value prior to 1940 throughout the system suggests that geological factors do not contribute to the observed variations in metal concentrations of heavy metals found in this area. The background concentrations of heavy metals found in this study for the Calcasieu River/Lake Complex were: Cu (10 mg kg?1), Cr (25 mg kg?1), Pb (8 mg kg?1), and Zn (40 mg kg?1), The main emphasis of the study focused along Bayou d'Inde due to the enhanced levels of heavy metals found.  相似文献   

16.
Organochlorine pesticide residues and PCBs were measured in 113 otter (Lutra lutra) scat samples from 94 sites in the River Clyde catchment, its estuary and neighboring coastal waters in western Scotland. Contents of pesticide residues were generally low. PCB amounts were high in some regions in the study area (geometric mean contents up to 19.5 mg kg?1 lipid). Potential sources of contamination included industrial areas, a sewage sludge dump and shipping facilities, both naval and commercial. PCBs in tissues were estimated from scats. Analysis of scats provides a useful technique of estimating potential contamination threats to otter populations and can be used to identify biologically significant hot-spots of contamination which may be missed by more familiar surveillance methods.  相似文献   

17.
Abstract

A range of locally available liming materials of different geological origin, particle size, and application rate were investigated in 15 field sites over a period of 8 years. At 5 sites, lime addition to soils caused average yield losses of 7%. Concentrations of Mn and Cu but not of boron and zinc in grains declined in limed plots. Decline in concentrations of Mn and Cu were significantly correlated with increasing soil pH-values. Crop data indicated that concentrations of Mn and Cu in grains reached low, critical levels. Yields declined at threshold values amounting to 15 mg Mn kg?1 for wheat and barley, 25 mg Mn kg?1 for rye, 30 mg Mn kg?1 for oat, and 3 mg Cu kg?1 for the four cereals.  相似文献   

18.
华南大宝山矿周边土壤和大豆的重金属污染   总被引：3，自引：0，他引：3  
Concentrations of Pb, Cd, Cu, Zn, Cr and Ni in soybean (Glycine max L.) grown near the Dabaoshan Mine were investigated, and their potential risk to the health of inhabitants was estimated. In the Fandong (FD) and Zhongxin (ZX) villages, which are near the Dabaoshan mineral deposit, concentrations of Pb (0.34 mg kg-1 for FD), Cd (0.23 mg kg-1 for ZX) and Cr (1.14 and 1.75 mg kg-1 for FD and ZX, respectively) in the seeds of soybean exceeded the tolerance limit set by Chinese standards. The estimated daily intakes (EDIs) from consumption of soybean seeds for FD inhabitants were 0.570, 0.170, 38.550, 142.400, 1.910 and 14.530 μg d-1 kg-1 boby weight for Pb, Cd, Cu, Zn, Cr and Ni, respectively. Our results indicate that soybeans grown in the vicinity of the Dabaoshan Mine accumulate some metals, and the seeds pose a potential health risk to the local inhabitants.  相似文献   

19.
《Journal of plant nutrition》2013,36(7):1071-1084
Calibration of field crop response to nutrient availability is the bases for making a fertilizer recommendation from soil and tissue analyses. The purpose of this study was to evaluate and summarize results from a series of experiments on silicon (Si) fertilization of rice in the Everglades Agriculture Area. Twenty-eight rice field experiments were conducted from 1992 through 1996. The experiments consisted of 2 to 5 rates of calcium silicate applied to soils (Histosols) of varying Si soil-test values. Soil samples were taken before planting and analyzed for acetic acid (0.5 mol L?1) extractable Si. Straw samples were collected at harvest and analyzed for total Si. Grain yield was determined. The “critical” levels for Si in the soil (point below which response to Si fertilizer is expected) calculated by the Cate & Nelson procedure was 19 mg Si L?1 soil. The amount of silicon to correct Si deficiency in the soil and to obtain optimum rice yield was 1500, 1120 and 0 kg ha?1 for low (<6 mg L?1), medium (6 to 24 mg L?1), and high (>24 mg L?1) level of soil Si, respectively. Silicon in the straw was classified as high when Si concentration was >34 g kg?1, medium when in between 17 and 34, and low when <17 g kg?1 (3.4 and 1.7%, respectively).

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20.
Abstract

Applications of zinc (Zn) and copper (Cu) at excessive rates may result in phytotoxicity. Experiments were conducted with mixtures of soils that were similar except for their Zn and Cu levels. The critical toxicity levels (CTL) in the soils and plants for these elements were determined. Peanut (Arachis hypogaea L.), soybean [Glycine max (L.) Merr.], corn (Zea mays L.), and rice (Oryza sativa L.) were the crops grown. One soil mixture had Mehlich 3‐extractable Zn concentrations up to 300 mg dm‐3 with no corresponding increase in soil Cu; two soil mixtures had soil Zn concentrations up to 400 and 800 mg dm‐3 with a corresponding increase in soil Cu up to 20 and 25 mg dm‐3, respectively; and four soil mixtures had no increase in soil Zn, but had Mehlich 1‐extractable Cu concentrations from 6 to 286 mg kg‐1. Under a given set of greenhouse conditions, the estimated Mehlich 3‐extractable Zn CTL was 36 mg dm‐3 for peanut, 70 mg dm‐3 for soybean, between 160 and 320 mg dm‐3 for rice, and >300 mg dm‐3 for corn. No soil Cu CTL was apparent for peanut or soybean, but for corn it was 17 mg dm‐3 and for rice 13 mg dm‐3. With different greenhouse procedures and the Mehlich 1 extractant, the soil CTL for rice was only 4.4 mg kg‐1. Therefore, peanut and soybean were more sensitive to Zn toxicity, whereas corn and rice were more sensitive to Cu toxicity. Plant Zn CTL for peanut was 230 mg kg‐1, while that for soybean was 140 mg kg‐1. Copper appeared to be toxic to corn and rice at plant concentrations exceeding 20 mg kg‐1.  相似文献   

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