Biomedical subjects

Tieheng Sun

Publications and source records attributed to Tieheng Sun.

At least 19 recordsLinked to original sources

PubMed2006

[An approach to the theoretical meaning of ecological remediation of contaminated soil].

The objectives of contaminated soil remediation are to transfer and transform the hazardous contaminants in soil, to eliminate and reduce their toxicity, and to restore or partly restore the ecological service function of soil. Since soil contamination is always a combined one, it is essential to use multiple methods to remediate contaminated soil. It is a tendency of soil remediation to use a uniform method, which aims to restore the ecological service function of soil by combining the restoration of internal function with external clean function. This paper discussed the concepts of ecological remediation of contaminated soil, and the ecological principles which should be obeyed in ecological remediation. Bioremediation is very important for ecological remediation, and the method organization should obey the principles of technique optimization. Remediation efficiency can be improved if self clean function of soil system is strengthened and activated, together witb external clean function. Ecological factor adjustment is essential for contaminated soil remediation, and also, a basic characteristic of ecological remediation and an important means for the enhancement of remediation efficiency. Ecological remediation should be harmonious, efficient, and stable. The final objective of ecological remediation is to restore the ecological service function of soil, in which, the evaluation of ecological remediation is the base. Ecological remediation theory shall play an important role in contaminated soil remediation.

Biodegradation, Environmental↗

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 pesticides on soil urease activity].

With simulation test, this paper studied the effects of chlorimuron-ethyl and furadan on the urease activity of six meadow brown soil and black soil samples. The results showed that within the range of test concentrations, these two pesticides could activate the urease activity of test soils, with the largest increment in meadow brown soil and black soil being 46.95% and 39.36% by chlorimuron-ethyl, and 21.08% and 12.70% by furadan, respectively. Quadratic polynomial equation could better describe the relationships between the concentrations of chlorimuron-ethyl and furadan and the activity of soil urease (P < 0.05). Judging from the equations for test pesticides, chlorimuron-ethyl had more significant effect than furadan.

Carbofuran↗

PubMed2005

Effect of linear alkylbenzene sulphonate (LAS) on the mineralization, metabolism and uptake of 14C-phenanthrene in a model ecosystem (water-lava-plant-air).

The aim of this work was to evaluate the effect of linear alkylbenzene sulfonate (LAS, 200 mg l(-1)) on the fate of phenanthrene in a model ecosystem "water-lava-hydrophytes-air". The experiments were conducted using two closed cultivation chamber systems. Rushes (Juncus effesus) were selected as a representative hydrophyte. Five hundred micrograms per liter of phenanthrene in a culture solution containing a 14C-activity of 75 microCi per chamber was applied (i) to investigate the degradation of the labeled test substance and the transfer processes within the system; (ii) to determine the mass-balance possible and (iii) to detect the occurrence of volatile test substances, their volatile metabolites and the degradation end-product CO2 in the gas phase. Most of the applied 14C-activity was found in the plant (41-45%), in which approximately 95% was associated with plant roots and approximately 5% with shoots. The 14C-activity recovered in the form of VOCs and CO2 was measured in lava (18-29%, 8-11%), and in the culture solution (10-14% and 1%), respectively. Majority of the applied 14C-activity existed in two forms, i.e. (1) polar metabolites (26%), of which 91% were found in plant roots, and (2) un-extractable residues (23%), most of which were in plant roots (40%) and bounded to lava (58%). The presence of LAS significantly increased the volatilization of phenanthrene and its metabolites, inhibited its mineralization and decreased the level of 14C-activity in lava. Moreover, LAS reduced the phenanthrene level in plant roots.

Air↗

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↗

PubMed2005

[Eco-toxicity diagnosis on sediments of petroleum wastewater irrigation channel].

Sediment samples were collected from several sites in the upper, mid and lower reaches of the petroleum wastewater irrigation channel in eastern Shenyang of China, and the concentrations of their Cu, Zn, Pb, Cd and mineral oil were analyzed. The results showed that the pollutants were accumulated in all of sediment samples, with 408-118,300 mg x kg(-1) mineral oil, 17.83-78.53 mg x kg(-1) Cu, 35.76-155.16 mg x kg(-1) Zn, 8.50-31.03 mg x kg(-1) Pb and 0.1-1.0 mg x kg(-1) Cd. The sediments showed an inhibition or stimulation effect on plant root elongation and a lethal and sub-lethal effect on earthworm. The inhibition rate of root elongation based on germination test was -29.81 to 93.8%. During 14 d exposure, the maximum mortality rate of earworm was 100%, and during 14d and 28d exposure, the inhibition rate of its body weight growth was -36.6%-(-)6.08% and -40.4%-6.1%, respectively. The study indicated that a long-term irrigation with petroleum wastewater resulted in the accumulation of pollutants in channel sediments and enhanced eco-toxicity.

Crops, Agricultural↗

PubMed2005

[Research progress on environmental carrying capacity].

To study the theories and quantification methods of environmental carrying capacity is of significance in reality for directing human beings economic behaviors and harmonizing the relationships between social development and environment. In this paper, the definition of environmental carrying capacity was introduced from the aspects of "capacity", "threshold" and "capability", with the main characteristics of objective and subjective, regional and temporal, and dynamic and adjustable, and its research progress was reviewed. On the basis of these, the quantification methods of environmental carrying capacity, including exponential assessment, carrying rate assessment, system dynamics, and multi-objective optimization, were analyzed, and the research perspectives of environmental carrying capacity were discussed.

Conservation of Natural Resources↗

PubMed2004

[Progress in pollution ecology of soil-plant systems and its expectation].

In order to promote the further healthy development and disciplinary construction of the rising discipline pollution ecology of soil-plant systems and give full play to its more and more important role in solving environmental pollution and food-chain safety at the national level, this paper reviewed the inceptive work and early researches in this scientific area, traced the development of disciplinary definition and connotation, and basic principles and methods, and expounded and prospected the scientific mission, principal research contents and future development of this subject.

Crops, Agricultural↗

PubMed2004

[Influence of acetochlor on Pb forms and their bioavailability in phaiozem of northeast China].

By using Pb-fractionation analytical methods and Pb-acetochlor response experiments, it was studied the Pb forms in clean and polluted phaiozems of northeast China and the response of Pb bioavailability to acetochlor application. The results showed that the dominant Pb forms in these soils were low bio-available organic-sulfide Pb and residual Pb, and the concentrations of high bio-available water-soluble and exchangeable Pb were relatively low. However, the ratio of bio-available Pb to total Pb was lower in polluted phaiozem than in clean phaiozem. The bioavailability of Pb in the soil was obviously increased after high dose of acetochlor was applied. The main reason was the contribution of organic-sulfide Pb to bio-available Pb interacted with acetochlor.

Biological Availability↗

PubMed2004

[Accumulation of pollutants in sediments and their eco-toxicity in the wastewater irrigation channel of western Shenyang].

Sediment samples were collected from several sites in the upper, mid and lower reaches of the petroleum wastewater irrigation channel in western Shenyang of China, and the concentrations of their heavy metal Cd and mineral oil were determined. The results showed that pollutants were accumulated in all test sediments, with 400-12,500 mg x kg(-1) mineral oil and 1.6-27.2 mg x kg(-1) Cd. The sediments had significant inhibition effects on plant and earthworm. The inhibition rate of root elongation based on germination test was 10%-60%. During 14 d and 28 d exposure, the mortality rate of earthworm was 0%-70% and 0%-85%, and the inhibition rate of its body weight growth was -21.9%-17.7% and -18.6%-37.0%, respectively. It indicated that a long-term irrigation with wastewater resulted in the accumulation of pollutants in channel sediments and enhanced eco-toxicity. As an important source of pollution, the migration and release of pollutants in sediments possessed potential risks to underground water and soil.

China↗

PubMed2004

[Soil nematode as a bioindicator of environment pollution].

As a part of mesofauna in soil ecosystem, nematode plays an important role in essential soil processes. Because of its unique attributes, nematode was widely used in the study of soil health indication. Based on the current studies at home and abroad, this paper discussed the function and application of nematode in indicating and diagnosing soil pollution, and the indices (maturity index, diversity index, similarity index, key species, N/C ratio, and physiological index) and their characteristics of nematode communities used as indicators. As a useful index of bioindicators in ecotoxicological diagnosis, the prospect of soil nematode application was of potential.

Animals↗

PubMed2004

[Bio-indicating function of soil protozoa to environmental pollution].

Due to the abundant species and huge biomass, soil protozoa play an important role in soil ecosystem. As a bio-indicator, soil protozoa have many advantages over other soil animals. Studies on the community structures, quantities, and dynamic variations of biodiversity of soil protozoa could provide powerful means to evaluate natural environmental changes and to monitor the environmental pollution brought by anthropic activities. Based on the current study at home and abroad, this paper gave a review on the function of soil protozoa in ecosystems, their advantages as bio-indicator, and their responses to environmental factors, soil contaminants and the change of atmospheric CO2. The application prospect of soil protozoa in eco-toxicity diagnosis was also discussed.

Animals↗

PubMed2003

[Effects of combined pollution of heavy metals on root vitality of wheat seeds].

The combined effects of Cu, Cd, Pb and Zn on the growth and activity of the seminal roots of wheat (Triticum aestivum) were studied by the method of quadratic regression revolution design. The mathematical models describing the above relations were established. As for the toxicity to the root vitality, their single effects, marginal utility and combined effects between two heavy metals were analyzed. The results showed that Pb had the most important effect on the activity of root, and then, Cu, Cd and Zn in sequence. The interaction between Cu and Cd, Cu and Zn, Zn and Cd, Cd and Pb had great effects on the activity of seminal roots. Furthermore, among the concentration range of 0 to 20 mg.L-1, as for Cu and Zn, the lowest density had the biggest marginal utility, while Cd and Pb had the biggest ones at the highest density.

Metals, Heavy↗

PubMed2003

[Effect of short-term phenanthrene stress on SOD activities and MDA contents in soybean (Glycine max) seedlings].

Growth of soybean (Glycine max) seedlings, changes of superoxide dismutase (SOD) activities, and malonyldialdehyde (MDA) contents were researched during different concentration phenanthrene stress and following recovery from stress. The results showed that seedling growth was interrupted after 5 d in 200 micrograms.g-1 phenanthrene treatment. However, during the period of recovery, growth was restored, although there was a delay in returning to control levels. The dose-related response of SOD activities were observed in manner of linear for 2 d and of parabola for 5 d and 8 d at 50-200 micrograms.g-1 phenanthrene. SOD activities of seedling were significantly induced by 100 and 200 micrograms.g-1 phenanthrene for 2 d (P < 0.05 and P < 0.01), while declined significantly under phenanthrene stress for 8 d, and was 88% of control at 200 micrograms.g-1 phenanthrene (P < 0.05). When releasing soybean seedlings from phenanthrene stress for 5 d to clear tap water for 2 d or 4 d, their SOD activities at 50 and 100 micrograms.g-1 phenanthrene recovered towards control level, while a significant increase in SOD activities was observed at 200 micrograms.g-1 phenanthrene (P < 0.05). The experiments also revealed that a significant increase of MDA contents in seedlings occurred after 5 d and 8 d in 100 and 200 micrograms.g-1 phenanthrene treatment (P < 0.05 and P < 0.01), which suggested that the membrane systems were damaged by phenanthrene stress. All of the above results showed that SOD activities of soybean seedling might be suitable to be the biomarkers of phenanthrene stress.

Malondialdehyde↗

PubMed2003

[Effects of chlorobenzene stress on seedling growth and cell division of Vicia faba].

Effects of 1, 2, 4-trichlorobenzene (TCB) stress on seedling growth, cell division and chromosomal aberration frequency of root-tip cells of Vicia faba were studied. The results indicated that the growth of the root length and mitotic index of root tip cells were successively decreased and even stopped with the increase of TCB concentrations and treatment duration. Numerical and structural chromosomal aberrations at metaphase and anaphase of root-tip cells in Vicia faba seedlings were produced by 50-300 micrograms.g-1 TCB treatment for 12-96 h. The percentage of c-mitosis, chromosomal bridge and chromosomal asymmetry array in root tip cells exposed to 50-100 micrograms.g-1 TCB for 12-24 h was up to 1.0-10.3%. The percentage of chromosomal stickness (S), chromosomal stickiness + chromosomal breakage (S + B), chromosomal stickness + chromosomal ring (S + R), chromosomal stickiness + chromosomal asymmetry array (S + A) and chromosomal stickness + chromosomal bridge (S + Be) in root tip cells reached 47.9-88.9%, and 18.1-29.6% for different kinds of chromosomal breakage at 300 micrograms.g-1 TCB for 12-96 h. Thus, the chromosomal aberration of root tip cells in Vicia faba seedlings could be used as a sensitive biomarker of monitoring soil contaminated with TCB.

Cell Division↗

PubMed2002

[Chlorobenze-stressing injury of the germination of soybean seed].

Effects of various doses of 1,2,4-trichlorobenze on seed germination and seedling growth of soybean were studied. The results indicated that 50-200 micrograms.g-1 of 1,2,4-trichlorobenze had no effect on the percentage of seed germination, but delayed the rate of seedling growth. The seed germination was stopped by 300 micrograms.g-1 of 1,2,4-trichlorobenze. The most activity of SOD took place on the 4th day after sowing of soybean seed in the normal condition, then tended to be in a certain level with a little alteration. Under the various dose stress of 1,2,4-trichlorobenze, the activity of SOD in soybean hypocotyl was decreased, while MDA and protein contents as well as diameter of hypocotyls increased. Seedlings growth, fresh weight(FW), dry weight(DW) were inhibited, while the ratio of FW/DW didn't change. Damage-level of wheat seedlings was increased with increasing 1,2,4-trichlorobenze concentrations. Roots were more sensitive to 1,2,4-trichlorobenze-stress than hypocotyls.

Chlorobenzenes↗

PubMed2002

[Acute toxicological effects of heavy metal pollution in soils on earthworms].

Acute and sub-acute lethal effects of single and combined Cu, Zn, Pb and Cd on earthworm was determined using meadow brown soil. Results indicated that the mortality of earthworm was significantly related with the concentrations of Cu and Zn in the soil (alpha = 0.05, RCu = 0.86, RPb = 0.87), and the inhibition rate of earthworm growth was significantly related with the concentration of Cu in the soil (alpha = 0.05, RCu = 0.84). There was no significant relation between the concentrations of other heavy metals tested and the death rate and the growth-inhibition rate. The degree of individual earthworm enduring the toxicity of heavy metals varied greatly. The threshold concentration of toxicity defined by statistical method, the level to conduce the death of individual earthworm was 300 mg.kg-1 for Cu, 1300 mg.kg-1 for Zn, 1700 mg.kg-1 for Pb, 300 mg.kg-1 for Cd. LC50 was 400-450 mg.kg-1 for Cu, 1500-1900 mg.kg-1 for Zn, 2350-2400 mg.kg-1 for Pb and 900 mg.kg-1 for Cd. Combined effects of single Cu, Zn, Pb and Cd to conduce more than 10% of the death rate of earthworm could result in 100% of the death rate of earthworm, thus showing the strong synergistic joint effect of the heavy metals.

Animals↗