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1.
Phytoaccumulation prospects of cadmium and zinc by mycorrhizal plant species growing in industrially polluted soils 总被引:2,自引:0,他引:2
The natural vegetation growing along a wastewater channel was subjected to analyze the uptake of Cadmium (Cd) and Zinc (Zn)
and their subsequent accumulation in aboveground and underground plant parts. Species which were mycorrhizal and growing in
soils receiving industrially contaminated wastewater were collected along with their rhizospheric soil samples. The nearby
uncontaminated control (reference) area was also subjected to sampling on similar pattern for comparison. Both Cd and Zn concentrations
were significantly higher in soils of the study area as compared to the reference site. Five plant species i.e. Desmostachya bipinnata, Dichanthium annulatum, Malvastrum coromandelianum, Saccharum bengalense, and Trifolium alexandrinum were analyzed for metal uptake. The maximum phytoaccumulation of Cd was observed in Desmostachya bipinnata (20.41 μg g−1) and Dichanthium annulatum (15.22 μg g−1) for shoot and root tissues, respectively. However, Malvastrum coromandelianum revealed maximum Zn accumulation for both the shoot and the root tissues (134 and 140 μg g−1, respectively). The examination of cleared and stained roots of the plants from both the areas studied revealed that all
of them were colonized to a lesser or a greater degree by arbuscular mycorrhizal (AM) fungi. The Cd hyperaccumulating grasses
i.e. Desmostachya bipinnata and Dichanthium annulatum, from study area had smaller root:shoot (R/S) ratio as compared to those growing on reference area indicating a negative
pressure of soil metal contamination. The lower R/S ratio in the mycorrhizal roots observed was probably due to increased
AM infection and its mediatory role in soil plant transfer of heavy metals. Furthermore, comparatively lower soil pH values
in the study areas may have played a key role in making the overall phytoavailability of both the metals. Consequently variations
in Cd and Zn tissue concentration among species were observed that also indicate the phytoaccumulation potential of the native
species. 相似文献
2.
The use of higher plants to remediate contaminated land is known as phytoremediation, a term coined 15 years ago. Among green technologies addressed to metal pollution, phytoextraction has received increasing
attention starting from the discovery of hyperaccumulator plants, which are able to concentrate high levels of specific metals
in the above-ground harvestable biomass. The small shoot and root growth of these plants and the absence of their commercially
available seeds have stimulated study on biomass species, including herbaceous field crops. We review here the results of
a bibliographical survey from 1995 to 2009 in CAB abstracts on phytoremediation and heavy metals for crop species, citations of which have greatly increased, especially after 2001. Apart from the most frequently cited
Brassica juncea (L.) Czern., which is often referred to as an hyperaccumulator of various metals, studies mainly focus on Helianthus annuus L., Zea mays L. and Brassica napus L., the last also having the greatest annual increase in number of citations. Field crops may compensate their low metal
concentration by a greater biomass yield, but available data from in situ experiments are currently very few. The use of amendments
or chelators is often tested in the field to improve metal recovery, allowing above-normal concentrations to be reached. Values
for Zn exceeding 1,000 mg kg−1 are found in Brassica spp., Phaseolus vulgaris L. and Zea mays, and Cu higher than 500 mg kg−1 in Zea mays, Phaseolus vulgaris and Sorghum bicolor (L.) Moench. Lead greater than 1,000 mg kg−1 is measured in Festuca spp. and various Fabaceae. Arsenic has values higher than 200 mg kg−1 in sorghum and soybean, whereas Cd concentrations are generally lower than 50 mg kg−1. Assisted phytoextraction is currently facilitated by the availability of low-toxic and highly degradable chelators, such
as EDDS and nitrilotriacetate. Currently, several experimental attempts are being made to improve plant growth and metal uptake,
and results are being achieved from the application of organic acids, auxins, humic acids and mycorrhization. The phytoremediation
efficiency of field crops is rarely high, but their greater growth potential compared with hyperaccumulators should be considered
positively, in that they can establish a dense green canopy in polluted soil, improving the landscape and reducing the mobility
of pollutants through water, wind erosion and water percolation. 相似文献
3.
J. W. Fourqurean N. Marbà C. M. Duarte E. Diaz-Almela S. Ruiz-Halpern 《Marine Biology》2007,151(1):219-232
Morphology, elemental content and isotopic composition of leaves of the seagrasses Posidonia oceanica and Cymodocea nodosa were highly variable across the Illes Balears, a Spanish archipelago in the western Mediterranean, and varied seasonally
at one site in the study area. The data presented in this paper generally expand the reported ranges of nitrogen, phosphorus,
iron and arsenic content and δ13C and δ15N for these species. Nitrogen and phosphorus content of P. oceanica leaves also showed significant seasonal variability; on an annual basis, P. oceanica leaves averaged 1.55% N and 0.14% P at this monitoring site. Both N and P were more concentrated in the leaves in winter
than in summer, with winter maxima of 1.76% N and 0.17% P and summer minima of 1.34% N and 0.11% P. There was no significant
annual pattern observed in the δ13C of P. oceanica leaves, but there was a repeated 0.6‰ seasonal fluctuation in δ15N. Mean annual δ15N was 4.0‰; δ15N was lowest in May and it increased through the summer and autumn to a maximum in November. Over the geographic range of
our study area, there were interspecific differences in the carbon, nitrogen and phosphorus content of the two species. Posidonia oceanica N:P ratios were distributed around the critical value of 30:1 while the ratios for C. nodosa were lower than this value, suggesting P. oceanica we collected was not consistently limited by N or P while C. nodosa tended toward nitrogen limitation. Nutrient content was significantly correlated to morphological indicators of plant vigor.
Fe content of P. oceanica leaves varied by a factor of 5×, with a minimum of 31.1 μg g−1 and a maximum of 167.7 μg g−1. Arsenic was present in much lower tissue concentrations than Fe, but the As concentrations were more variable; the maximum
concentration of 1.60 μg g−1 was eight times as high as the minimum of 0.20 μg g−1. There were interspecific differences in δ13C of the two species; C. nodosa was consistently more enriched (δ13C = −7.8 ± 1.7‰) than P. oceanica (−13.2 ± 1.2‰). The δ13C of both species decreased significantly with increasing water depth. Depth related and regional variability in the δ13C and δ15N of both species were marked, suggesting that caution needs to be exercised when applying stable isotopes in food web analyses. 相似文献
4.
This article reports a novel way to synthesize carbon nanotubes and Cu/ZnO nanoparticles using metal hyperaccumulator plants.
Metal hyperaccumulator plants are traditionally used for phytoremediation to clean soil polluted by toxic metals. However,
the transfer of toxic metals in plant shoots and leaves is an environmental issue because animals and other living organisms
feeding on plants will transfer the metals to the ecosystem. Therefore, we suggest that hyperaccumulator plants could be used
to synthesize nanoparticles. Here, Brassica juncea L., a Cu-hyperaccumulator plant, was collected around a copper mine and used as a raw chemical to produce carbon nanotubes
and Cu/ZnO nanoparticles. The chlorophyll in shoots of B. juncea plants was ethanol extracted to yield chlorophyllin. Cu and Zn were extracted by HNO3 to form Cu/Zn(NO3)2. The chlorophyllin reacted with Cu/Zn(NO3)2 to form Cu/Zn chlorophyllin. Cu/ZnO nanoparticles were synthesized by direct precipitation of Cu/Zn chlorophyllin with NaOH
and ethanol. The vascular bundles in B. juncea plants, which have been purified and carbonized by HNO3, were rapidly heated to about 400°C and then they were cooled to room temperature to obtain carbon nanotubes. Results indicate
that the outer diameter of carbon nanotubes was around 80 nm. Cu/ZnO nanoparticles have a Cu0.05Zn0.95O composition, and had a diameter of about 97 nm. Our study not only inspires the search for a new strategy on the synthesis
of nanostructure from renewable natural products, but also breaks through the traditional and limited ideas about the reuse
of metals by hyperaccumulator plants. 相似文献
5.
Sequential extraction of cadmium in different soil phases and plant parts from a former industrialized area 总被引:2,自引:1,他引:1
Cd concentrations in mobile phases of soil are more representative than total Cd concentration for estimating Cd bioavailability,
physicochemical reactivity and mobility. In this study, selective sequential extraction procedures were used to determine
Cd in different soil phases. Soil samples and plants grown in these soils were collected from a serpentine and copper-mining
area in Maden-Elazig-Turkey. The extracted fractions were exchangeable/carbonate, reducible-iron/manganese oxides, oxidizable-organic
matter and sulfides, and residual phases except silicates. Concentrations of Cd in soils and plant samples were determined
by flame atomic absorption spectrometry and inductively coupled plasma-mass spectrometry. We found that Cd concentrations
in the EDTA and NH2OH·HCl extracts are higher in most soil samples compared to the other extracts. We conclude that Cd levels in mobile phases
are unexpectedly high. The observed Cd concentrations are in ranges of 0.03–3.4 mg kg−1 for soil and 0.02–2.5 mg kg−1 for plant parts. The percentages of cadmium up to 56% in exchangeable and carbonates fractions were observed to be significantly
higher than in those values less than 2% reported in literature. This study has shown that the modified extraction method
can be usefully applied to determine Cd concentrations in potentially mobile phase of soil. Furthermore, it was concluded
that Brassicasea and Rumex leaves can be used as hyperaccumulator plants because their translocation factor and/or enrichment coefficient values were
found to be higher than 1.0. 相似文献
6.
Presence of Alexandrium catenella and paralytic shellfish toxins in finfish, shellfish and rock crabs in Monterey Bay, California, USA 总被引:1,自引:0,他引:1
The central California coast is a highly productive, biodiverse region that is frequently affected by the toxin-producing
dinoflagellate Alexandrium catenella. Despite the consistent presence of A. catenella along our coast, very little is known about the movement of its toxins through local marine food webs. In the present study,
we investigated 13 species of commercial finfish and rock crabs harvested in Monterey Bay, California for the presence of
paralytic shellfish toxins (PSTs) and compared them to the presence of A. catenella and PSTs in sentinel shellfish over a 3-year period. Between 2003 and 2005, A. catenella was noted in 55% of surface water samples (n = 307) and reached a maximum concentration of 17,387 cells L−1 at our nearshore site in Monterey Bay. Peak cell densities occurred in the month of July and were associated with elevated
shellfish toxicity in the summers of 2004 and 2005. When A. catenella was present, particulate PSTs were detected 71% of the time and reached a maximum concentration of 962 ng STXeq L−1. Of the 13 species tested, we frequently detected PSTs in Pacific sardines (Sardinops sagax; maximum 250 μg STXeq 100 g−1), northern anchovies (Engraulis mordax; maximum 23.2 μg STXeq 100 g−1), brown rock crabs (Cancer antennarius; maximum 49.3 μg STXeq 100 g−1) and red rock crabs (C. productus; 23.8 μg STXeq 100 g−1). PSTs were also present in one sample of Pacific herring (Clupea pallas; 13.3 μg STXeq 100 g−1) and one sample of English sole (Pleuronectes vetulus; 4.5 μg STXeq 100 g−1), and not detected in seven other species of flatfish tested. The presence of PSTs in several of these organisms reveals
that toxins produced by A. catenella are more prevalent in California food webs than previously thought and also indicates potential routes of toxin transfer
to higher trophic levels.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
A test of elemental defence against slugs by Ni in hyperaccumulator and non-hyperaccumulator Streptanthus species 总被引:2,自引:0,他引:2
Summary. Tissues of most plant species contain < 10 μg Ni g−1 but Ni hyperaccumulators contain more than 1000 μg Ni g−1 . Hyperaccumulated Ni can defend plants from some herbivores but the defensive role of lesser Ni concentrations is little explored. We raised five species of Streptanthus (Brassicaceae) native to ultramafic soils, one of which (S. polygaloides) is a Ni hyperaccumulator whereas the others are simply Ni-tolerant, on Ni-amended and unamended green-house soils to create plants differing in Ni concentrations. On high-Ni soil, leaves of the hyperaccumulator contained 3800 μg Ni g−1 whereas leaves of non-hyperaccumulator species contained 41–64 μg Ni g−1. Plants of all species grown on low-Ni soils had < 14 μg Ni g−1. Slugs (Limax maximus) were fed plant material in no-choice tests over a 50-day period and survival and mass changes were recorded. All slugs fed high-Ni leaves of the hyperaccumulator species died within 21 d. Slugs fed high-Ni leaves of the other species did not differ significantly in survival or mass change from those fed low-Ni leaves. In choice tests, slugs (Lehmannia valentiana) offered both high- and low-Ni S. polygaloides leaves did little damage to high-Ni leaves. We conclude that hyperacumulated Ni can defend S. polygaloides from slug herbivory via both toxicity and deterrence, but these defensive effects do not extend to Streptanthus species containing < 70 μg Ni g−1. 相似文献
8.
We measured the uptake kinetics of four metals (Cd, Cr, Se and Zn) in two marine macroalgae (the green alga Ulva lactuca and the red alga Gracilaria blodgettii). Metal uptake generally displayed a linear pattern with increasing exposure time. With the exception of Cr, which exhibited
comparable uptake rate constants at different concentrations, uptake rate constants of Cd, Se and Zn decreased with increasing
metal concentration, indicating that the seaweeds had a higher relative uptake at lower metal concentration. Uptake of Cd
and Zn was higher in U. lactuca than in G. blodgettii, whereas uptake of Cr and Se was comparable between the two species. Only Cd and Zn uptake in U. lactuca was significantly inhibited by dark exposure. A decrease in salinity from 28 to 10‰ enhanced the uptake of Cd, Cr, Se and
Zn in U. lactuca 1.9-, 3.0-, 3.6-, and 1.9-fold, respectively. In G. blodgettii, Cd uptake increased twofold when salinity was decreased from 28 to 10‰, whereas uptake of Cr and Zn was not significantly
affected by salinity change. The calculated depuration rate constants of metals in U. lactuca were 0.01 d−1 for Cd, 0.05 to 0.08 d−1 for Cr, 0.14 to 0.16 d−1 for Se, and 0.12 to 0.15 d−1 for Zn, and were relatively independent of the metal body burden in the algae. The predicted bioconcentration factor was
3 × 104 for Cd, 2 × 103 for Cr, 40 to 150 for Se, and 1 to 2 × 104 for Zn in U. lactuca. Our kinetic study suggested that U. lactuca would be a good biomonitor of Cr and Zn contamination in coastal waters.
Received: 14 September 1998 / Accepted: 29 May 1999 相似文献
9.
The cancer risk and the non-cancer hazard index for inhabitants exposed to As, Cd, Cu and Zn in the soils and stream waters
of the abandoned Songcheon Au–Ag mine area were evaluated. Mean concentrations of As, Cd, Cu, Pb and Zn in agricultural soils
were 230, 2.5, 120, 160, and 164 mg kg−1, respectively. Mean concentrations of As, Cd and Zn of the water in the stream where drinking water was drawn was 246 μg
L−1, 161 μg L−1 and 3899 μg L−1, respectively. These levels are significantly higher than the permissible levels for drinking water quality recommended by
Korea and WHO. The resulting human health risks to farmers who inhabited the surrounding areas due to drinking water were
summarized as follows: (1) the non-cancer health hazard indices showed that the toxic risk due to As and Cd in drinking water
were 10 and 4 times, respectively, greater than those induced by the safe average daily dosages of the respective chemicals.
(2) the cancer risk of As for exposed individuals through the drinking water pathway was 5 in 1000, exceeded the acceptable
risk of 1 in 10,000 set for regulatory purposes. 相似文献
10.
Myong Hwan Sohn Kyung Won Seo Yong Seok Choi Sang Joon Lee Young Sil Kang Yang Soon Kang 《Marine Biology》2011,158(3):561-570
The marine dinoflagellate Cochlodinium polykrikoides is a harmful and highly motile algal species. To distinguish between the motility characteristics of solitary and chain-forming
cells, the swimming trajectories and speeds of solitary cells and 2- to 8-cell chains of C. polykrikoides were measured using a digital holographic particle tracking velocimetry (PTV) technique. C. polykrikoides cells exhibited helical swimming trajectories similar to other dinoflagellate species. The swimming speed increased as the
number of cells in the chain increased, from an average of 391 μm s−1 (solitary cells) to 856 μm s−1 (8-cell chain). The helix radius R and pitch P also increased as the number of cells in the chain increased. R increased from 9.24 μm (solitary cell) to 20.3 μm (8-cell chain) and P increased from 107 μm (solitary cell) to 164 μm (8-cell chain). The free thrust-generating motion of the transverse flagella
and large drag reduction in the chain-forming cells seemed to increase the swimming speed compared to solitary cells. The
measured swimming speeds agreed with those from field observations. The superior motility of chain-forming C. polykrikoides cells may be an important factor for its bloom, in addition to the factors reported previously. 相似文献
11.
Great scallop, Pecten maximus, and blue mussel, Mytilus edulis, clearance rate (CR) responses to low natural seston concentrations were investigated in the laboratory to study (1) short-term
CR variations in individual bivalves exposed to a single low seston diet, and (2) seasonal variations in average CR responses
of bivalve cohorts to natural environmental variations. On a short temporal scale, mean CR response of both species to 0.06 μg L−1 chlorophyll a (Chl a) and 0.23 mg L−1 suspended particulate matter (SPM) remained constant despite large intra-individual fluctuations in CR. In the seasonal study,
cohorts of each species were exposed to four seston treatments consisting of ambient and diluted natural seston that ranged
in mean concentration from 0.15 to 0.43 mg L−1 SPM, 0.01 to 0.88 μg L−1 Chl a, 36 to 131 μg L−1 particulate organic carbon and 0.019 to 0.330 mm3 L−1 particle volume. Although food abundance in all treatments was low, the nutritional quality of the seston was relatively
high (e.g., mean particulate organic content ranged from 68 to 75%). Under these low seston conditions, a high percentage
of P. maximus (81–98%) and M. edulis (67–97%) actively cleared particles at mean rates between 9 and 12 and between 4 and 6 L g−1 h−1, respectively. For both species, minimum mean CR values were obtained for animals exposed to the lowest seston concentrations.
Within treatments, P. maximus showed a greater degree of seasonality in CR than M. edulis, which fed at a relatively constant rate despite seasonal changes in food and temperature. P. maximus showed a non-linear CR response to increasing Chl a levels, with rates increasing to a maximum at approximately 0.4 μg L−1 Chl a and then decreasing as food quantity continued to increase. Mean CR of M. edulis also peaked at a similar concentration, but remained high and stable as the food supply continued to increase and as temperatures
varied between 4.6 and 19.6°C. The results show that P. maximus and M. edulis from a low seston environment, do not stop suspension-feeding at very low seston quantities; a result that contradicts previous
conclusions on the suspension-feeding behavior of bivalve mollusks and which is pertinent to interpreting the biogeographic
distribution of bivalve mollusks and site suitability for aquaculture. 相似文献
12.
Movement rate, oxygen consumption, and respiratory tree ammonium concentration were measured in situ in the holothurians Pearsonothuria graeffei and Holothuria edulis in the Agan-an Marine Reserve, Sibulan, Philippines (9°20′30″N, 123°18′31″E). Measurements were made both day and night for
both species during April–July 2005. P. graeffei had significantly higher movement rate during the day than at night (1.14 and 0.27 m h−1, respectively; three-way ANOVA, P < 0.05) while H. edulis had higher movement rate at night compared to the day (0.83 and 0.07 m h−1, respectively), spending the daylight hours sheltering under coral. More than 80% of H. edulis had movement rate of zero during the day. Oxygen consumption of P. graeffei was significantly higher during the day than at night (1.61 and 0.83 μmol O2 g−1 h−1, respectively; two-way ANCOVA, P < 0.05), but the reduction at night was not as pronounced as the reduction in movement. H. edulis had a 75% reduction in oxygen consumption during the day compared to night (0.51 and 1.96 μmol O2 g−1 h−1, respectively), matching this species’ reduced movement rates during the day. Ammonium concentration in water withdrawn from
the respiratory trees of P. graeffei during the day (12.0 μM) was three times higher than in respiratory tree water sampled at night (4.3 μM) and 15 times higher
than ambient seawater (0.8 μM; three-way ANOVA, P < 0.05). Ammonium concentration in the respiratory tree water of H. edulis was six times higher at night (14.6 μM) than during the day (2.2 μM) and 16 times higher than that of ambient seawater (0.9 μM).
Even though H. edulis and P. graeffei are found within the same coral reef environment, they may affect different substrates and reef organisms due to their different
habitats and distinct but opposite diel cycles. 相似文献
13.
A. Cornils S. B. Schnack-Schiel M. Böer M. Graeve U. Struck T. Al-Najjar C. Richter 《Marine Biology》2007,151(4):1261-1274
A total of 12 feeding experiments were conducted in the northern Gulf of Aqaba during spring (March/April) and autumn (September/October)
2002 at the Marine Science Station (MSS) in Aqaba. Females of three species of clausocalanids were selected: Clausocalanus
farrani, C. furcatus and Ctenocalanus vanus. Natural occurring particle (NOP) larger than 5 μm were investigated as food source. The ambient chlorophyll a concentration at sampling depth (∼70 m) ranged between 0.15 and 1.00 μg chl a l−1 and NOP concentrations ranged between 1.78 and 14.0 × 103 cells l−1 during the sampling periods. The division of particles into five size classes (5–10, 10–20, 20–50, 50–100 and >100 μm) revealed
that most of the particles were found in the size classes below 50 μm (81–98%), while most of the natural occurring carbon
(NOC) was concentrated in the size classes larger than 20 μm (70–95%). Ingestion rates were food density dependent rather
than size dependent ranging between 0.02 and 1.65 × 103 NOP ind−1 day−1 and 0.01 and 0.41 μg NOC ind−1 day−1, respectively, equivalent to a body carbon (BC) uptake between 0.4 and 51.8% BC day−1. The share of the size classes to the total ingestion resembled in most cases the size class composition of the natural particle
community. 相似文献
14.
The influence of naturally occurring uraniferous black shales on cadmium, molybdenum and selenium concentrations in soils
and plants is examined. The possible implications of element concentrations to animal and human health are considered for
the Deog-Pyoung area.
Geochemical surveys have been undertaken within 13 river tributary valleys in the area underlain by uraniferous black shales
and black slates or grey chlorite schists. Sampling of rocks, soils and plants has been carried out along transect lines within
each valley. Samples were analysed for trace elements by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)
and for uranium by Neutron Activation Analysis (NAA). Soil pH, cation exchange capacity, loss on ignition and particle size
distribution have been measured for selected samples.
Average trace element concentrations of the Okchon uraniferous black shales were 6.3 μg g−1 Cd, 136 μg g−1 Mo and 8.6 μg g−1 Se. Soils derived from these rocks tend to reflect their extreme geochemical composition. Trace element concentrations in
alluvial soils derived in part from these black shales averaged 1.2 μg g−1 Cd, 20 μg g−1 Mo and 1.5 μg g−1 Se. Trace element concentrations in plants were found to be influenced by those of soils. Cadmium accumulated in tobacco
leaves up to 46 μg g−1 (D.M.) and leafy plants such as lettuce contain up to 0.5 μg g−1 Se (D.M.).
In addition to total concentrations in soils, soil pH is a major factor influencing uptake of Mo into crop plants and soil
texture for Se. Concentrations of trace elements in plants also varied between plant species. The relative concentrations
of Cd were found to vary in the order tobacco > lettuce > red pepper > rice grain.
Elevated concentrations of Cd in crop plants and in tobacco may possibly have deleterious effects on human health in this
area. The low Cu:Mo ratio in rice stalk of 2.65:1 may be associated with disturbed Cu metabolism in ruminant animals which
regularly consume this material. 相似文献
15.
Risk to humans of consuming metals in anchovy (<Emphasis Type="Italic">Coilia</Emphasis> sp.) from the Yangtze River Delta 总被引:1,自引:0,他引:1
Fengyan Liu Jiachun Ge Xin Hu Teng Fei Yuehua Li Yuan Jiang Zhiqiang Xu Shuyan Ding John P. Giesy 《Environmental geochemistry and health》2009,31(6):727-740
Concentrations of metals were determined in four species of anchovy (Coilia sp.) from the Yangtze River, Taihu Lake, and Hongze Lake in Jiangsu Province, China. Concentrations of Cr in anchovy fish
muscle ranged from 2.6 × 10−2 to 5.0 mg/kg ww, and Coilia nasus taihuensis in Jiaoshan, Taihu Lake contained the highest concentrations of Cr, which was almost 111-fold higher than the mean value
at other locations. Concentrations of Pb ranged from 1.5 × 10−2 to 1.3 × 10−1 mg/kg ww. Comparisons of concentrations of lead (Pb) among the four species indicated that anadromous species contained higher
concentrations of Pb than did freshwater species. However, concentrations of Pb in C. nasus from the Nanjing and Haimen locations in the Yangtze River were not significant higher than those of two freshwater species:
C. nasus taihuensis from Taihu Lake and C. brachygnathus from Hongze Lake (Duncan’s test, α = 0.05). While concentrations of Cd and Zn ranged from 7.0 × 10−4 to 3.6 × 10−3 mg/kg ww and 3.4 to 4.8 mg/kg ww, respectively, there were no significant differences in concentrations among the eight locations.
The only concentration of the metals studied that exceeded the Chinese National Standard was Cr in Coilia from Jiaoshan, Taihu Lake, which was 2.5-fold higher than the standard. These results indicate that people who consume the
genus Coilia are not at risk due to concentrations of metals, except Cr in C. nasus taihuensis from Jiaoshan in Taihu Lake. Concentrations of all of the metals studied except for Cr were similar to or less than those
of metals in most other areas in the world. 相似文献
16.
Heraclides brasiliensis (Lepidoptera: Papilionidae) larvae feed preferably on Piperaceae, foraging successfully on leaf tissues even though species
of this contain high levels of secondary metabolites such as amides and lignans, associated with diverse biological activities
including insecticidal properties. Studies examining the metabolism of chemical constituents in Piperaceae by insects are
rare. In this study, we characterized the metabolites of 4-nerolidylcatechol (4-NC), the major constituent of Piper umbellata (Piperaceae), and E-2,3-dihydro-3-(3,4-dihydroxyphenyl)farnesoic acid, compounds from fecal material of H. brasiliensis larvae fed a diet containing only P. umbellata leaves. The biotransformed product was also detected in larval and pupal tissues. Moreover, we observed deactivation of the
toxicity of P. umbellata leaves against brine shrimp after their metabolism in H. brasiliensis larvae from a LC50 of 523.3 to 3,460.7 μg/mL. This deactivation is closely associated with the biotransformation of 4-NC to E-2,3-dihydro-3-(3,4-dihydroxyphenyl)farnesoic acid, which showed LC50 of 8.0 and >1,000 μg/mL, respectively. 相似文献
17.
Simmons RW Noble AD Pongsakul P Sukreeyapongse O Chinabut N 《Environmental geochemistry and health》2009,31(1):71-79
Research undertaken over the last 40 years has identified the irrefutable relationship between the long-term consumption of
cadmium (Cd)-contaminated rice and human Cd disease. In order to protect public health and livelihood security, the ability
to accurately and rapidly determine spatial Cd contamination is of high priority. During 2001–2004, a General Linear Regression
Model Irr-Cad was developed to predict the spatial distribution of soil Cd in a Cd/Zn co-contaminated cascading irrigated
rice-based system in Mae Sot District, Tak Province, Thailand (Longitude E 98°59′–E 98°63′ and Latitude N 16°67′–16°66′).
The results indicate that Irr-Cad accounted for 98% of the variance in mean Field Order total soil Cd. Preliminary validation
indicated that Irr-Cad ‘predicted’ mean Field Order total soil Cd, was significantly (p < 0.001) correlated (R
2 = 0.92) with ‘observed’ mean Field Order total soil Cd values. Field Order is determined by a given field's proximity to
primary outlets from in-field irrigation channels and subsequent inter-field irrigation flows. This in turn determines Field
Order in Irrigation Sequence (Field OrderIS). Mean Field Order total soil Cd represents the mean total soil Cd (aqua regia-digested) for a given Field OrderIS. In 2004–2005, Irr-Cad was utilized to evaluate the spatial distribution of total soil Cd in a ‘high-risk’ area of Mae Sot
District. Secondary validation on six randomly selected field groups verified that Irr-Cad predicted mean Field Order total
soil Cd and was significantly (p < 0.001) correlated with the observed mean Field Order total soil Cd with R
2 values ranging from 0.89 to 0.97. The practical applicability of Irr-Cad is in its minimal input requirements, namely the
classification of fields in terms of Field OrderIS, strategic sampling of all primary fields and laboratory based determination of total soil Cd (T-CdP) and the use of a weighed coefficient for Cd (CoeffW). The use of primary fields as the basis for Irr-Cad is also an important practical consideration due to their inherent ease
of identification and vital role in the classification of fields in terms of Field OrderIS. The inclusion of mean field order soil pH (1:5water) to the Irr-Cad model accounted for over 79% of the variation in mean Field Order bio-available (DTPA (diethylenetriaminepentaacetic
acid)-extractable) soil Cd. Rice is the staple food of countries of the Greater Mekong Sub-region (includes Vietnam, Myanmar,
Lao PDR, Thailand and Yunnan Province, China). These countries also have actively and historically mined Zn, Pb, and Cu deposits
where Cd is likely to be a potential hazard if un-controlled discharge/runoff enters areas of rice cultivation. As such, it
is envisaged that the Irr-Cad model could be applied for Cd hazard assessment and effectively form the basis of intervention
options and policy decisions to protect public health, livelihoods, and export security. 相似文献
18.
Summary. Nickel hyperaccumulator plants contain unusually elevated levels of Ni (>1,000 mg Ni kg−1). The high Ni concentration of hyperaccumulator tissues may affect ecosystem processes such as decomposition, but this has
yet to be studied under field conditions. We used Senecio coronatus Thunb. (Harv.) from two pairs of serpentine sites: one member of each pair contained a hyperaccumulator population and the
other a non-hyperaccumulator population. Our main goal was to determine if leaf Ni status (hyperaccumulator or non-hyperaccumulator)
affected leaf decomposition rate on serpentine sites. We also used a non-serpentine site on which leaves from all four S. coronatus populations were placed to compare decomposition at a single location. Dried leaf fragments were put into fine-mesh (0.1 mm)
nylon decomposition bags and placed on field sites in mid-summer (early February) 2000. Sets of bags were recovered after
1, 3.5, and 8 months, their contents dried and weighed, and the Ni concentration and total Ni content of high-Ni leaves was
measured. For the serpentine sites, there was no significant effect of leaf Ni status or site type on decomposition rates
at 1 and 3.5 months. By 8 months, leaf Ni status and site type significantly influenced decomposition on one pair of sites:
hyperaccumulator leaves decomposed more slowly than non-hyperaccumulator leaves, and leaves of both types decomposed more
slowly on the non-hyperaccumulator site. At the non-serpentine site, the highest-Ni leaves (15,000 mg Ni kg−1) decomposed more slowly than all others, but leaves containing 9,200 mg Ni kg−1 did not decompose more slowly than non-hyperaccumulator leaves. Nickel in decomposing hyperaccumulator leaves was released
rapidly: after 1 month 57–68% of biomass was lost and only 9–28% of original Ni content remained. We conclude that very high
(>10,000 mg Ni kg−1) leaf Ni concentrations may slow decomposition and that Ni is released at high rates that may impact co-occurring litter-
and soil-dwelling organisms. 相似文献
19.
Assimilation efficiencies and turnover rates of trace elements in marine bivalves: a comparison of oysters, clams and mussels 总被引:2,自引:0,他引:2
Assimilation efficiencies (AEs) and physiological turnover-rate constants (k) of six trace elements (Ag, Am, Cd, Co, Se, Zn) in four marine bivalves (Crassostrea virginica Gmelin, Macoma balthica Linnaeus, Mercenaria mercenaria Linnaeus, and Mytilus edulis Linnaeus) were measured in radiotracer-depuration experiments. Egestion rates of unassimilated elements were highest during
the first 24 h of depuration and declined thereafter. Significant egestion of unassimilated Co, however, continued for up
to 5 d in Macoma balthica, Mercenaria mercenaria and Mytilus edulis. With the exception of the extremely low values for 110 mAg, 109Cd, and 65Zn in C. virginica, physiological turnover-rate constants (k) showed no general pattern of variation among elements, bivalve species or food types, and were relatively invariant. Values
from ≤0.001 to 0.1 d−1 were observed, but excluding those for Co, most values were ≤0.04 d−1. In all four species, the AEs of Ag, Am, and Co were generally lower than those of Cd, Se, and Zn. The AEs of Ag, Cd, Se,
and Zn in these bivalves are directly related to the proportion of each element in the cytoplasmic fraction of ingested phytoplankton,
indicating that >80% of elements in a prey alga's cytoplasm was assimilated. C. virginica, Macoma balthica, and Mercenaria mercenaria assimilated ∼36% of the Ag and Cd associated with the non-cytoplasmic (membrane/organelle) fraction of ingested cells in
addition to the cytoplasmic fraction. The ratio of AE:k, which is proportional to the consumer–prey trace-element bioaccumulation factor (concentration in consumer:concentration
in prey) was generally greater for Cd, Se, and Zn than for Ag, Am, and Co. This ratio was lowest in Mytilus edulis, suggesting that this bivalve, the most widely employed organism in global biomonitoring, is relatively inefficient at accumulating
important elements such as Ag, Cd, and Zn from ingested phytoplankton.
Received: 7 February 1997 / Accepted: 24 February 1997 相似文献
20.
Ping Li Xinbin Feng Guangle Qiu Lihai Shang Guanghui Li 《Environmental geochemistry and health》2009,31(6):683-691
The total mercury (T-Hg) and methyl mercury (Me-Hg) concentrations in the hair were measured to evaluate mercury (Hg) exposure
for the residents in Da-shui-xi Village (DSX) and Xia-chang-xi Village (XCX) in the Wanshan Hg mining area, Guizhou Province,
Southwestern China. The mean concentrations in the hair of DSX residents were 5.5 ± 2.7 μg/g and 1.9 ± 0.9 μg/g for T-Hg and
Me-Hg, respectively. The concentrations in the hair of XCX residents were 3.3 ± 1.4 μg/g and 1.2 ± 0.5 μg/g for T-Hg and Me-Hg,
respectively. Hair Me-Hg concentrations were significantly correlated to T-Hg (r = 0.42, P < 0.01) in the two sites; on average, hair Me-Hg concentration accounted for 40 and 44% of T-Hg for DSX and XCX residents,
respectively. Age has no obvious correlation with hair Hg and the hair Hg levels showed a significant gender difference, with
higher T-Hg and Me-Hg concentrations in the hair from males than females. The rice collected from the two sites showed high
levels of T-Hg and Me-Hg concentration. The results indicated a certain Hg exposure for the residents in DSX and XCX in the
Wanshan Hg mining area. 相似文献