Biomedical subjects

Qixing Zhou

Publications and source records attributed to Qixing Zhou.

At least 19 recordsLinked to original sources

PubMed2006

Effects of plant arsenic uptake and heavy metals on arsenic distribution in an arsenic-contaminated soil.

This study examined the effects of heavy metals and plant arsenic uptake on soil arsenic distribution. Chemical fractionation of an arsenic-contaminated soil spiked with 50 or 200mg kg(-1) Ni, Zn, Cd or Pb was performed before and after growing the arsenic hyperaccumulator Pteris vittata L for 8weeks using NH(4)Cl (water-soluble plus exchangeable, WE-As), NH(4)F (Al-As), NaOH (Fe-As), and H(2)SO(4) (Ca-As). Arsenic in the soil was present primarily as the recalcitrant forms with Ca-As being the dominant fraction (45%). Arsenic taken up by P. vittata was from all fractions though Ca-As contributed the most (51-71% reduction). After 8weeks of plant growth, the Al-As and Fe-As fractions were significantly (p<0.01) greater in the metal-spiked soils than the control, with changes in the WE-As fraction being significantly (p=0.007) correlated with plant arsenic removal. The plant's ability to solubilize soil arsenic from recalcitrant fractions may have enhanced its ability to hyperaccumulate arsenic.

Arsenic↗

PubMed2006

Flowering stage characteristics of cadmium hyperaccumulator Solanum nigrum L. and their significance to phytoremediation.

The Cd accumulation and biomass characteristics of a newly found Cd-hyperaccumulator Solanum nigrum L. were investigated at the flowering stage and the mature stage. The results showed that the concentration of Cd in the stems and leaves of S. nigrum harvested at the flowering stage was up to 83.1% and 85.5% of that at the mature stage, and the dry-weight sum of the stems and leaves of S. nigrum harvested at the flowering stage was 93.4% of that at its seed maturity. The Cd-removing ratio by the shoots of S. nigrum harvested at the flowering stage was 87.5% of that at the mature stage. It was also found by observing the growth duration of S. nigrum that the frostless period at the experimental site was at least twice as long as the growth duration from the seedling-transplanted phase to the flowering stage of the hyperaccumulator. Therefore, S. nigrum could be transplanted into contaminated soils twice in one year by harvesting the hyperaccumulator at its flowering stage based on climatic conditions of the site and traits of the plant growth. In particular, the extraction efficiency of Cd by harvesting the shoots of S. nigrum at its flowering stage twice in one year could increase 75.0% compared to that of at its single maturity. Thus, the method of multiple harvesting would be very important to increase phytoremediation efficiency in practice.

Biodegradation, Environmental↗

PubMed2006

Accumulation of Pb, Cu, and Zn in native plants growing on a contaminated Florida site.

Contamination of heavy metals represents one of the most pressing threats to water and soil resources as well as human health. Phytoremediation can be potentially used to remediate metal-contaminated sites. This study evaluated the potential of 36plants (17species) growing on a contaminated site in North Florida. Plants and the associated soil samples were collected and analyzed for total metal concentrations. While total soil Pb, Cu, and Zn concentrations varied from 90 to 4100, 20 to 990, and 195 to 2200mg kg(-1), those in the plants ranged from 2.0 to 1183, 6.0 to 460, and 17 to 598mg kg(-1), respectively. None of the plants were suitable for phytoextraction because no hyperaccumulator was identified. However, plants with a high bioconcentration factor (BCF, metal concentration ratio of plant roots to soil) and low translocation factor (TF, metal concentration ratio of plant shoots to roots) have the potential for phytostabilization. Among the plants, Phyla nodiflora was the most efficient in accumulating Cu and Zn in its shoots (TF=12 and 6.3) while Gentiana pennelliana was most suitable for phytostabilization of sites contaminated with Pb, Cu and Zn (BCF=11, 22 and 2.6). Plant uptake of the three metals was highly correlated, whereas translocation of Pb was negatively correlated with Cu and Zn though translocation of Cu and Zn were correlated. Our study showed that native plant species growing on contaminated sites may have the potential for phytoremediation.

Biodegradation, Environmental↗

PubMed2006

Availability and assessment of fixing additives for the in situ remediation of heavy metal contaminated soils: a review.

The use of low-cost and environmental safety amendments for the in situ immobilization of heavy metals has been investigated as a promising method for contaminated soil remediation. Natural materials and waste products from certain industries with high captive capacity of heavy metals can be obtained and employed. Reduction of extractable metal concentration and phytotoxicity could be evaluated and demonstrated by the feasibility of various amendments in fixing remediation. In this review, an extensive list of references has been compiled to provide a summary of information on a wide range of potentially amendment resources, including organic, inorganic and combined organic-inorganic materials. The assessment based on the economic efficiency and environmental risks brought forth the potential application values and future development directions of this method on solving the soil contamination.

Chelating Agents↗

PubMed2006

[An approach to the establishment of remediation standards for contaminated soils].

With the rapid development of remediation technology for contaminated soils in China, remediation standard has become a bottleneck in judging the effects of this technology. In this paper, some suggestions on the establishment of remediation standards for contaminated soils, e.g., choice of contaminants, methods of detection, classification of contaminated soils, protection of groundwater, and assessment of toxicological risks were put forward, based on the analysis of the disadvantages of Soil Environmental Quality Standard.

Ecology↗

PubMed2006

[Absorption and accumulation of heavy metals by plants around a smelter].

The study on the absorption and accumulation of heavy metals lead, zinc, copper and cadmium by 8 plant species around a smelter showed that the metals accumulation by plants differed with plant species, their parts, and kinds of metals. Abutilon theophrasti had a higher capability of absorbing and accumulating Pb, Conyza canadensis, Ambrosia trifida, Polygonumn lapathifolium, A. theophrasti, Solanum nigrum, Chenopodium acuminatum and Helianthus tuberosus had a higher capability of absorbing and accumulating Zn, C. acuminatunz and A. theophrasti had a higher capability of absorbing and accumulating Cu, and S. nigrum, C. acuminatum, A. theophrasti, P. lapathifolium and C. canadensis had a higher capability of absorbing and accumulating Cd. These plants had TF values higher than 1, and were suitable for phytoextraction to remedy polluted soil. As for the plants with TF values lower than 1, they were suitable as the phytostabilizers of heavy metals-contaminated lands.

Absorption↗

PubMed2006

[Research advance in characteristics and mechanisms of Nereis diversicolor endurance against environmental pollution].

Nereis diversicolor is an ecologically keystone species of invertebrate that lives in the mud of marine-terrestrial interlaced zone. This species can accumulate a large number of toxic heavy metals such as copper, cadmium and zinc in its body, and thus, shows a high endurance against toxic heavy metals. This paper summarized the latest research advance at home and abroad in the characteristics and mechanisms of N. diversicolor endurance against heavy metals and organic contaminants. N. diversicolor could achieve its heavy metals- endurance through several eco-chemical processes, e.g., mucus secretion and contaminants excretion. The former could form a protective layer or integrate with dissolved ions of pollutants, and thus, decrease the bioavailability of pollutants, while the latter could lessen the pollutants' bio-toxicity. More researches believe that the toxic heavy metals in N. diverdicolor body are stored in non-toxic physicochemical forms, i. e., bound to metal-binding protein, such as metallothionein (MTs), metallothionein-like proteins (MTLP) and cytosolic heat-stable thiolic compounds (CHSTC), or incorporated into insoluble deposits or granules. The pivots of future researches on the ecotoxicology of N. diversicolor and its endurance mechanisms against pollutants were proposed.

Animals↗

PubMed2006

[Toxic effects of monosodium glutamate wastewater on crop seed germination and root elongation].

To make a comprehensive assessment on monosodium glutamate wastewater pollution, a pollution exposure experiment was carried out on the seed germination and root elongation of wheat, Chinese cabbage and tomato by using the wastewater discharged from different processing phases of monosodium glutamate production. The results showed that there were significantly positive linear relationships between the inhibition rates of wheat seed germination and root elongation and the COD(Cr) of mother liquor scraps. The toxicity of monosodium glutamate wastewater to the test crops was in the order of tomato > Chinese cabbage > wheat, indicating that tomato was most sensitive to the wastewater, and could be considered as an ideal toxic bioindicator. The half-effect concentration (IC50) based on the seed germination and root elongation of test crops exposed to the wastewater discharged from various processing phases of monosodium glutamate production was 22.0 to approximately 32432 mg x L(-1) and 17.3 to approximately 3320 mg x L(-1), respectively.

Crops, Agricultural↗

PubMed2006

[Research advances in ecotoxicology and risk assessment of chemical mixtures at low doses].

Chemicals in the environment often exist as mixtures and at low doses, whose ecotoxicological diagnosis and risk assessment are hard to be done with the help of the research results on the ecotoxicity of high-level exposure of single chemicals. This paper reviewed the research advances in ecotoxicology and risk assessment of low-dose chemical mixture contamination, with the focus on the molecular toxicological methods and the risk assessment approaches and schemes of simple and complex mixtures. Comments were given on the development directions of low-dose chemical mixture research, including the necessity of searching for sensitive endpoints, involving the approaches of other disciplines, increasing data accumulation, and setting up a comprehensive and identical risk assessment system.

Dose-Response Relationship, Drug↗

PubMed2006

[Effects of methamidophos and copper on ecological detoxification of acetochlor by earthworm in phaeozem].

By using microcosm culture method, this paper studied the dynamic changes of acetochlor degradation by earthworm in phaeozem with methamidophos or copper addition, aimed to approach the feasibility of using earthworm to intensify the detoxification of acetochlor. The results showed that the dynamics of acetochlor degradation accorded with the first-order reaction kinetics, whether earthworm existed or not. The activities of earthworm accelerated the detoxification of acetochlor, and the coexistence of methamidophos or copper with acetochlor evidently inhibited the degradation of acetochlor. The coexistence of methamidophos and acetochlor or of copper and higher concentration acetochlor altered the dynamics of acetochlor degradation, while the coexistence of copper and lower concentration acetochlor didn't have any obvious effect on the detoxification of acetochlor.

Animals↗

PubMed2005

Removal of polycyclic aromatic hydrocarbons from manufactured gas plant-contaminated soils using sunflower oil: laboratory column experiments.

Laboratory column experiments were performed to remove PAHs (polycyclic aromatic hydrocarbons) from two contaminated soils using sunflower oil. Two liters of sunflower oil was added to the top of the columns (33 cm x 21 cm) packed with 1 kg of PAH-contaminated soil. The sunflower oil was applied sequentially in two different ways, i.e. five additions of 400 ml or two additions of 1l. The influence of PAH concentration and the volume of sunflower oil on PAH removal were examined. A soil respiration experiment was carried out and organic carbon contents of the soils were measured to determine degradability of remaining sunflower oil in the soils. Results showed that the sunflower oil was effective in removing PAHs from the two soils, more PAHs were removed by adding sunflower oil in two steps than in five steps, probably because of the slower flow rate in the former method. More than 90% of total PAHs was removed from a heavily contaminated soil (with a total 13 PAH concentration of 4721 mg kg(-1)) using 4 l of sunflower oil. A similar removal efficiency was obtained for another contaminated soil (with a total 13 PAH concentration of 724 mg kg(-1)), while only 2l was needed to give a similar efficiency. Approximately 4-5% of the sunflower oil remained in the soils. Soil respiration curves showed that remaining sunflower oil was degraded by allowing air exchange and supplying with nutrients. Organic carbon content of the soil was restored to original level after 180 d incubation. These results indicated that the sunflower oil had a great capacity to remove PAHs from contaminated soils, and sunflower oil solubilization can be an alternative technique for remediation of PAH contaminated soils.

Carbon↗

PubMed2005

Effects of herbicide chlorimuron-ethyl on physiological mechanisms in wheat (Triticum aestivum).

Changes in the activity of antioxidant enzymes including peroxidases (POD) and superoxide dismutases (SOD) and in the contents of chlorophyll (CHL), malondialdehyde (MDA), and soluble proteins (SP) in wheat (Triticum aestivum) under the stress of chlorimuron-ethyl in soil were examined. Chlorimuron-ethyl induced oxidative stress that was indicated by elevated MDA content in leaves and roots after a 1-day exposure. The 300-microg/kg chlorimuron-ethyl treatment caused significant damage to CHL accumulation. The higher POD activity in roots than in leaves may be the result of the tissue-specific gene expression in the roots. Our data could suggest that the plant has the capacity to counteract the oxidative stress caused by 5-150 microg/kg chlorimuron-ethyl exposure at the first stage, but the capacity would be lost with exposure time. It is indicated that the increase of POD activity in the leaves may have been caused by H(2)O(2) produced from sources other than SOD. The damage to the antioxidative defensive systems in plants is affected by the concentration of chlorimuron-ethyl and exposure time, and the defensive effect of antioxidative enzymes is completely lost with prolonged exposure. When treated with 300 microg/kg of chlorimuron-ethyl, a significant decrease of SP content and SOD activity in the leaves and roots indicated that the decrease of SP content and the activity of SOD can be considered biomarkers of the serious stress of chlorimuron-ethyl in soil. The increase of SP content in leaves after 3-4 days of exposure to 5-150 microg/kg chlorimuron-ethyl suggests that the enhanced POD activity was due to true induction of de novo synthesis rather than reactivation of preexisting apoprotein. It can also be concluded that dose-response relationships exist only between the SP content in roots and leaves and the concentration of chlorimuron-ethyl.

Chlorophyll↗

PubMed2005

Interaction of polycyclic aromatic hydrocarbons and heavy metals on soil enzyme.

Actions and interactions of heavy metals (cadmium, zinc and plumbum) and polycyclic aromatic hydrocarbons (PAHs) [phenanthrene, fluoranthene, benzo(a)pyrene] on the soil urease and dehydrogenase activity were studied after 49 days exposure. The experimental approach was based on the uniform design which can cut the experiment time and improve the efficiency of experiments. Data treatment was essentially based on the multiple regression technique. The results showed that the action and interaction between heavy metals and PAHs were strongly dependent on the time of pollution. The dehydrogenase exhibits more sensitive to the combined pollution than urease. The negative interaction between Zn and Cd to hydrogenase activity and the combined stimulatory activity of Phenanthrene and Benzo(a)pyrene (or fluoranthene) to soil enzyme were observed. The interactions between Zn (Cd) and phenanthrene towards urease (dehydrogenase) were positive, and the interaction between Zn and benzo(a)pyrene to urease activity was negative. This study corresponds to exploratory phase in order to reveal interaction effects of heavy metals and PAHs on the soil enzyme and then to set up more in-depth analysis to increase progressively the understanding of the ecotoxicological mechanisms involved.

Bacteria↗

PubMed2005

Toxic effects of Al-based coagulants on Brassica chinensis and Raphanus sativus growing in acid and neutral conditions.

The ecotoxicological effects of aluminum (Al)-based coagulants are of concern because of their wide-ranging applications in wastewater treatment and water purification. As important Al-based coagulants, AlCl(3) and PAC (polyaluminum-chloride) were selected as examples to examine the toxic effects on representative vegetables including the cabbage Brassica chinensis and the radish Raphanus sativus over a range of exposure concentrations in neutral (pH 7.00) and acidic (pH 4.00) conditions, using seed germination and root elongation in the early-growth stage as indicators of toxicity. The results showed that root elongation of the two vegetables was a more sensitive indicator than was seed germination for evaluating the toxicity of Al. As a single influencing factor, H(+) had no significant direct effects on root elongation of Brassica chinensis and Raphanus sativus under the experimental conditions. The toxicity of Al played the main role in inhibiting root elongation and seed germination and was strongly related to changes in pH. There was a markedly positive relationship between the inhibitory rate of root elongation, seed germination, and the concentration of Al at pH 4.00 (p < 0.01). The toxic effect of AlCl(3) on Brassica chinensis was less with a neutral pH than at pH 4.00, but Raphanus sativus was more susceptible to AlCl(3) toxicity at a neutral pH than at pH 4.00. Both Raphanus sativus and Brassica chinensis had a more toxic response to a low concentration (<64 mg . L(-1)) of PAC in a neutral condition than in an acidic condition. Undoubtedly, the Al toxicity caused by Al-based coagulants at a neutral pH is relevant when treatment solids are used in agriculture.

Aluminum↗

PubMed2005

Joint effects of acetochlor and urea on germinating characteristics of crop seeds.

In order to evaluate ecological risk of agrochemicals in common use, joint toxic effects of acetochlor and urea on germinating characteristics of Chinese cabbage (Brassica Pekinensis Rupr) seeds were investigated using the water-culture method and the soil-culture method. The results indicated that excessive application of acetochlor and urea, when the concentrations were higher than 31.3 mg x kg(-1) for acetochlor and 500 mg x kg(-1) for urea, had strong inhibitory effects on the rate of seed germination, root elongation and hypocotyl length of Chinese cabbage. The inhibitory rate of the germinating characteristics of Chinese cabbage seeds was significantly increased with an increase in the concentration of acetochlor or urea. The two agrochemicals in water had a stronger toxicity than these in the soil at the same concentration. Among the three indexes, hypocotyl length was the most sensitive to the toxicity of acetochlor and urea.

Brassica↗

PubMed2005

Impacts of methamidophos, copper, and their combinations on bacterial community structure and function in black soil.

The potential ecotoxicologial risks of methamidophos, copper, and their combinations on microbial community of black soil ecosystem in the Northeast China were assessed in species richness and structures by using 16S rDNA-PCR-DGGE analysis approach, and functional characteristics at community levels by using BIOLOG(GN) system analysis method as well as two conventional methods (DHA and SIR). All results of DGGE banding fingerprint patterns (amplified by bacterial specific 16S rDNA V3 high variable region universal primer) indicated that the species richness of bacterial community in tested soil was significantly decreased to different extents by using different concentrations of single methamidophos, copper, especially some of their combinations had worse effects than their corresponding single factors. In addition, the structures of soil bacterial community had been disturbed under all stresses applied in this study because of the enrichment of some species and the disappearance of other species from the bacterial community. The effects of the single factors with lower concentrations on the community structure were weaker than those with higher concentrations. Moreover, the bacterial community structures under the combined stresses of methamidophos and copper were significantly different from those of control and their corresponding single factors. The change of DHA and carbon source substrate utilizing fingerprint patterns based on BIOLOG(GN) system were two relatively sensitive directors corresponding to the stress presented in this study. Between methamodophos and copper, there happened the significant joint-toxic actions when they were used in combination on DHA and carbon source substrate utilizing fingerprint patterns of soil bacterial communities. The DHA of soil under the combined stresses was lower than that of the control and that under the single factors, and the BIOLOG(GN) substrate utilizing patterns of soil treated by combinations were distinctively differentiated from the control and their corresponding single factors. From all of above, the methamidophos, copper, especially their combinations had the clearly potential ecotoxicological risks to influence the natural soil microbial ecological system by changing the structure, richness, and the functional characteristics of microbial community.

Bacteria↗

PubMed2005

Short-term toxic effects of chlorobenzenes on broadbean (Vicia faba) seedlings.

The root growth, changes in superoxide dismutase (SOD, EC 1.15.1.1) activity, malonyldialdehyde (MDA) and total soluble protein level of broadbean (Vicia faba) seedlings were researched at different soil concentrations of chlorobenzene (CB), 1,2,4-trichlorobenzene (TCB) and hexachlorobenzene (HCB). The results showed that root growth of seedlings was interrupted after 5 d of 50-200 microg x g(-1) TCB treatment. During a 3 d recovery period, root growth was, however, restored to some extent although there was a delay in returning to the control level. The total soluble protein content in seedlings increased with TCB concentration and duration of exposure. Effect of TCB stress on SOD activity in seedlings displayed a significant dose-effect relationship for 1-5 d of 50-200 microg x g(-1) treatment. When broadbean seedlings were placed in clean tap water for 3 d following exposure to 5 d of TCB stress to clear tap water for 3 d, SOD activity at 50 microg x g(-1) TCB recovered towards control level (P>0.05) while a significant increase in SOD activity was observed at 100 and 200 microg x g(-1) TCB compared to control (P<0.05). The experiments also revealed that a significant increase of MDA level in seedlings occurred after 3 and 5 d of 100 and 200 microg x g(-1) TCB treatment (P<0.05 and P<0.01), and there was a positive correlation between TCB concentration and MDA level. All the above results showed that SOD activity and MDA level of broadbean seedlings might be proposed as the biomarkers for short-term TCB contamination in soil. Compared to TCB, the toxicity of 50-1000 microg x g(-1) CB or HCB in soil to broadbean seedlings was not observed after a 3 d exposure.

Chlorobenzenes↗

PubMed2005

Ecotoxicity of soils contaminated with industrial and domestic wastewater in western Shenyang, China.

Soil samples were collected from 7 sites in the up-, mid- and down-reach along and nearby the wastewater irrigation channel, western Shenyang of China. The concentrations of selected pollutants (mineral oil, PAHs--polycycle aromatic hydrocarbons and Cd) were determined by UV spectrometer, HPLC and AAS (atomic adsorption spectrometer) spectrometer, respectively. Toxicity effects of soils were evaluated by seedling emergence test with root length of wheat as the end-point and by earthworms test with the mortality rate and inhibition rates of body weight as endpoints. Results showed accumulation of pollutants for most soils with concentration of 200.2 mg x kg(-1)-1600 mg x kg(-1) for mineral oil, 0.33 mg x kg(-1)-1.81 mg x kg(-1) for Cd and 900.16 mg x kg(-1)-2737.91 mg x kg(-1) for PAHs. The inhibition rates of root elongation were from -20% up to 40%, and mortality rates of earthworms ranged from 0%-40% from the exposure period of two weeks to eight weeks by sampling interval of two weeks, the inhibition rates of earthworm growth were from -19.36% to 34.53%, showing effects of stimulation at 2 weeks to an increasing effects of inhibition at 4, 6 and 8 weeks, respectively. Mortality rates correlated with the loss of body weight of earthworms. This study indicated the potential risk of pollutants of environmental low content in soil by the determination of selected chemicals combined with toxicity indexes.

Animals↗