The impact of backpack load on adolescent's stair descent gait.

This study investigates the impact of increasing backpack load on the gait of adolescents during stair descent. Sixteen healthy male students (age = 12.9 ± 0.6 years) were required to descend the stairs in 4 loaded conditions. The kinematic, kinetic, and EMG data were collected synchronously and gait parameters, especially indicators of balance control, were analyzed. The posterior tilt angles (COM-COP IA in the sagittal plane) (0 %-42 %, 48 %-53 %, 58 %-91 %, p < 0.01), trunk anterior tilt angles (9-33 %, 51-65 %, p < 0.01), and CV of stride length (p < 0.01) increased with the backpack load. The COM-Step edge separation decreased with the increased backload (p < 0.01). In addition, the hip flexion torque (25-40 %, 45-51 %, p < 0.01), the rectus femoris activation, and the hip stiffness increased significantly as the load up to 15 % Body Weight (BW)and 20 % BW. The increasing backpack load may affect adolescent's stair descent gait. Especially as the load was up to 15 % BW, the adolescents' bodies tended to tilt backwards relative to the support foot during the single stance phase. They may activate the hip flexors and tilt forward the trunk to recover from the balance perturbation, which was associated with increased hip flexion torques. This adjustment was more pronounced with the increasing backpack load. However, excessive forward flexion may increase the risk of forward falls. The boundaries of adjustment need further research in the future. Findings from this study provide baseline information on the intrinsic mechanisms of balance control during stair descent.

The effect of aerobic dancing on physical fitness and cognitive function in older adults during the COVID-19 pandemic-a natural experiment.

During the Coronavirus disease (COVID-19), the physical activity of older adults is at a lower level. The study aimed to examine the effectiveness of aerobic dancing on physical fitness and cognitive function in older adults. We conducted a randomized controlled trial with 34 older adults who were assigned into an aerobic dancing group and a control group. Three dance sessions weekly for 60 â€‹min were scheduled for the aerobic dancing group for a total of 12 weeks. Physical fitness, blood pressure, lipids, glucose, cognitive function were assessed before and after the intervention. Baseline adjusted Analysis of Covariance (ANCOVA) was used to determine whether outcome variables varied between groups at pre-test and post-test. Effect size (Cohen's d) was calculated to determine the differences between groups from baseline to post-test. After 12 weeks, we found that the aerobic dancing group showed significant improvement in memory (portrait memory: F â€‹= â€‹10.45, p â€‹= â€‹0.003, d â€‹= â€‹1.18). The Limit of Stability (LOS) parameters in the aerobic dancing group displayed a significant increase after the intervention (right angle: F â€‹= â€‹5.90, p â€‹= â€‹0.022, d â€‹= â€‹0.60; right-anterior angle: F â€‹= â€‹4.23, p â€‹= â€‹0.049, d â€‹= â€‹0.12). Some beneficial effects were found on flexibility, grip strength, balance and subjective well-being (sit and reach: F â€‹= â€‹0.25, p â€‹= â€‹0.62, d â€‹= â€‹-0.40; grip strength: F â€‹= â€‹3.38, p â€‹= â€‹0.08, d â€‹= â€‹0.89; one-legged standing with eyes closed: F â€‹= â€‹1.26, p â€‹= â€‹0.27, d â€‹= â€‹0.50) in the aerobic dancing group. Aerobic dancing training was effective in improving memory and balance ability in older adults during the COVID-19 pandemic in China. In the future, aerobic dancing is a promising tool to encourage physical activity in older adults.

Association between Dietary Patterns and Physical Fitness among Chinese Children and Adolescents in Shaanxi Province.

BACKGROUND: This study aims to investigate the associations between dietary patterns (breakfast, egg, dairy products, and sugared beverage intake frequencies) and physical fitness among Chinese children and adolescents in Shaanxi Province. METHODS: Data were extracted from the Chinese National Survey on Students' Constitution and Health (CNSSCH). The study ultimately included 7305 participants (48.4% male, 51.6% female) aged 6-22 in Shaanxi Province, China. Multiple linear regression was used to examine the association of the frequency of breakfast, egg, dairy product, and sugared beverage intakes with physical fitness. RESULTS: The frequency of breakfast, egg, and dairy product intakes were all independently and positively associated with the level of physical fitness. The frequency of sugared beverage intake was negatively associated with the level of physical fitness. CONCLUSION: Healthier dietary patterns (i.e., higher breakfast, egg, and dairy product intakes and lower sugared beverage intake) were associated with greater physical fitness. Specifically, maintaining a healthy dietary pattern of breakfast, egg, and dairy product intakes can positively affect the strength and endurance performance of children and adolescents. Increased dairy product intake plays a crucial part in boosting the physical fitness total scores of children and adolescents.

Trends in Physical Fitness and Nutritional Status among School-Aged Children and Adolescents during the COVID-19 Pandemic in Shaanxi, China-A Cross-Sectional Study.

BACKGROUND: This study aimed to explore the characteristics of trends in physical fitness and nutritional status among school-aged students during the COVID-19 pandemic, which could help to develop targeted guidelines and policies for students (adolescents) to promote health during lockdowns resulting from public health emergencies. METHODS: The physical fitness and nutritional status were measured from 2019 to 2021; the correlation between years and grade were analyzed. RESULTS: a declining trend was found in aerobic fitness, strength fitness, speed fitness, and BMI during this lockdown. CONCLUSION: The changes in dietary behavior and the decrease in outdoor physical activities may be the reason for the decline. Furthermore, differences in subjects' growth and limited space at home must be considered in the formulation of exercise and nutritional plans. According to the results of our study, exercise for aerobic fitness should receive more attention when students are enduring a pandemic lockdown. In addition, saying "no" to high-calorie foods in the form of snacking and ultra-processed food was the key to improving subjects' nutritional status.

Correlation between Campus-Built Environment and Physical Fitness in College Students in Xi'an-A GIS Approach.

BACKGROUND: This research aimed to investigate the correlation between students' physical fitness and campus-built environment, which could put forward some suggestions for the construction of a campus environment. METHOD: Four colleges in Xi'an were regarded as special "semi-closed" spaces. Combined with ArcGIS and SPSS, the correlation between the built environment of colleges and the students' physical fitness test results in 2019 was analyzed (n = 1498). RESULTS: regarding the men questioned in this research, there was a significant correlation between street connectivity and vital capacity, grip strength, 50 m running, 1000 m running, a significant correlation between land use mix and vital capacity, sit-and-reach, pull-up, grip strength, a significant correlation between green space per capita and vital capacity, grip strength, 50 m running, and a significant correlation between walk score and vital capacity, pull-up, grip strength, and 50 m running. Regarding the women questioned in this research, there was a significant correlation between street connectivity and vital capacity, grip strength, 50 m running, 800 m running, curl-up, a significant correlation between land use mix and vital capacity, sit-and-reach, curl-up, grip strength, 800 m running, a significant correlation between green space per capita and vital capacity, grip strength, curl-up, sit-and-reach, and a significant correlation between walk score and vital capacity, curl-up, grip strength, and 800 m running. CONCLUSION: the built environment on campus can indirectly affect the physical fitness of college students. Increasing the number of intersections and short connections of campus streets, ensuring that the green space of the campus meets the standards, and reasonably arranging the site selection of buildings are conducive to improving the physical fitness of students.

Coupling between Nitrogen Fixation and Tetrachlorobiphenyl Dechlorination in a Rhizobium-Legume Symbiosis.

Legume-rhizobium symbioses have the potential to remediate soils contaminated with chlorinated organic compounds. Here, the model symbiosis between Medicago sativa and Sinorhizobium meliloti was used to explore the relationships between symbiotic nitrogen fixation and transformation of tetrachlorobiphenyl PCB 77 within this association. 45-day-old seedlings in vermiculite were pretreated with 5 mg L-1 PCB 77 for 5 days. In PCB-supplemented nodules, addition of the nitrogenase enhancer molybdate significantly stimulated dechlorination by 7.2-fold and reduced tissue accumulation of PCB 77 (roots by 96% and nodules by 93%). Conversely, dechlorination decreased in plants exposed to a nitrogenase inhibitor (nitrate) or harboring nitrogenase-deficient symbionts (nifA mutant) by 29% and 72%, respectively. A range of dechlorinated products (biphenyl, methylbiphenyls, hydroxylbiphenyls, and trichlorobiphenyl derivatives) were detected within nodules and roots under nitrogen-fixing conditions. Levels of nitrogenase-derived hydrogen and leghemoglobin expression correlated positively with nodular dechlorination rates, suggesting a more reducing environment promotes PCB dechlorination. Our findings demonstrate for the first time that symbiotic nitrogen fixation acts as a driving force for tetrachlorobiphenyl dechlorination. In turn, this opens new possibilities for using rhizobia to enhance phytoremediation of halogenated organic compounds.

Rhizobial symbiosis alleviates polychlorinated biphenyls-induced systematic oxidative stress via brassinosteroids signaling in alfalfa.

The role of symbiotic rhizobia in the alleviation of polychlorinated biphenyl (PCB)-induced phytotoxicity in alfalfa and the brassinosteroid (BR) hormone signaling involved were investigated during phytoremediation. The association between alfalfa and Sinorhizobium meliloti was adopted as a remediation model. Phytotoxicity due to PCB 77 (3,3',4,4'-tetrachlorobiphenyl) exerted adverse impacts on plant performance (biomass accumulation and photosynthesis) and elicited cellular oxidative stress (overproduction of reactive oxygen species, lipid peroxidation, and cell necrosis) which was largely attenuated by pre-inoculation with S. meliloti strain NM. The protective role may have been achieved as a result of strengthening of basic antioxidant defense before stress as evidenced by the augmented activity and gene expression of antioxidative enzymes (peroxidase, glutathione reductase, superoxide dismutase, catalase, and ascorbate peroxidase) of both leaves and roots. In nodulated seedlings peroxidase showed additive increased activity following PCB exposure but the activities of the other four enzymes tended to remain stable after stress. Furthermore, application of strain NM and brassinolide both triggered the accumulation of endogenous BRs and the antioxidant network, while pre-treatment of seedlings with a biosynthetic inhibitor of BRs, brassinazole, abolished the rhizobia-induced activation of detoxification responses towards PCB. These observations indicate that association with S. meliloti NM enhanced the systemic antioxidant defenses of alfalfa to detoxify PCB, at least in part, via BR-dependent signaling pathways. These results contribute to our knowledge of the 'logistic role' played by rhizobia in assisting the phytoremediation of PCB-contaminated soils and suggest an optimum manipulation strategy for bioremediation.

Biodegradation of pentachloronitrobenzene by Cupriavidus sp. YNS-85 and its potential for remediation of contaminated soils.

Pentachloronitrobenzene (PCNB) is a toxic chlorinated nitroaromatic compound. However, only a few bacteria have been reported to be able to utilize PCNB. In the present study, one pentachloronitrobenzene (PCNB)-degrading bacterium, Cupriavidus sp. YNS-85, was isolated from a contaminated Panax notoginseng plantation. The strain co-metabolized 200 mg L-1 PCNB in aqueous solution with a removal rate of 73.8% after 5 days. The bacterium also degraded PCNB effectively under acid conditions (pH 4-6) and showed resistance to toxic trace elements (arsenic, copper, and cadmium). Its ability to utilize proposed PCNB intermediates as sole carbon sources was also confirmed. The soil microcosm experiment further demonstrated that bacterial bioaugmentation enhanced the removal of PCNB (37.8%) from soil and the accumulation of pentachloroaniline (89.3%) after 30 days. Soil enzyme activity and microbial community functional diversity were positively influenced after bioremediation. These findings indicate that Cupriavidus sp. YNS-85 may be a suitable inoculant for in situ bioremediation of PCNB-polluted sites, especially those with acid soils co-contaminated with heavy metal(loid)s.

Non-target effects of repeated chlorothalonil application on soil nitrogen cycling: The key functional gene study.

The widespread and increasing application of chlorothalonil (CTN) raises concerns about its non-target impacts, but little information is available on the effect of CTN on the key functional genes related to soil nitrogen (N) cycling, especially in the case of repeated applications. In the present study, a microcosm incubation was conducted to determine CTN residues and the impacts on the abundances of key functional genes related to N cycling after repeated CTN applications. The results demonstrated that repeated CTN applications at the recommended application rate and five times the recommended rate led to the accumulation of CTN residue in soil at concentrations of 5.59 and 78.79 mg kg(-1), respectively, by the end of incubation. Real time PCR (RT-PCR) revealed that repeated CTN applications had negative effects on the chiA and aprA gene abundances. There were significantly negative correlations between CTN residues and abundances of AOA and AOB genes. In addition, the abundances of key functional genes involved in soil denitrification were declined by repeated CTN applications with the sole exception of the nosZ gene. This study suggests that repeated CTN applications could lead to the accumulation of CTN residue and generate somewhat inconsistent and erratic effects on the abundances of key functional genes related to soil N cycling.

Isolation of the PCB-degrading bacteria Mesorhizobium sp. ZY1 and its combined remediation with Astragalus sinicus L. for contaminated soil.

A bacterial strain ZY1 capable of utilizing PCBs as its carbon source was isolated from the root nodules of Chinese milk vetch (Astragalus sinicus L.). The strain was identified as Mesorhizobium sp. according to its physiological-biochemical properties and the analysis of its 16S rRNA gene sequence. When the initial OD600 was 0.15, 62.7% of 15 mg L(-1) 3,3',4,4'-TCB in a liquid culture was degraded by Mesorhizobium sp. ZY1 within 10 days. Mesorhizobium sp. ZY1 also greatly increased the biotransformation of soil PCBs. Pot experiments indicated that the soil PCB concentrations of a single incubation of strain ZY1 (R) and a single planting of A. sinicus (P) decreased by 20.5% and 23.0%, respectively, and the concentration of PCBs in soil treated with A. sinicus and strain ZY1 decreased by 53.1%. We also observed that A. sinicus-Mesorhizobium sp. ZY1 treatment (PR) improved plant biomass and the concentration of PCBs in plants compared with a single A. sinicus planting treatment (P). The results suggest that the synergistic association between A. sinicus and PCBs-degrading Mesorhizobium sp. ZY1 can stimulate the phytoextraction of PCBs and the rhizosphere microflora to degrade PCBs, and might be a promising bioremediation strategy for PCB-contaminated soil.

Trichoderma reesei FS10-C enhances phytoremediation of Cd-contaminated soil by Sedum plumbizincicola and associated soil microbial activities.

This study aimed to explore the effects of Trichoderma reesei FS10-C on the phytoremediation of Cd-contaminated soil by the hyperaccumulator Sedum plumbizincicola and on soil fertility. The Cd tolerance of T. reesei FS10-C was characterized and then a pot experiment was conducted to investigate the growth and Cd uptake of S. plumbizincicola with the addition of inoculation agents in the presence and absence of T. reesei FS10-C. The results indicated that FS10-C possessed high Cd resistance (up to 300 mg L(-1)). All inoculation agents investigated enhanced plant shoot biomass by 6-53% of fresh weight and 16-61% of dry weight and Cd uptake by the shoots by 10-53% compared with the control. All inoculation agents also played critical roles in increasing soil microbial biomass and microbial activities (such as biomass C, dehydrogenase activity and fluorescein diacetate hydrolysis activity). Two inoculation agents accompanied by FS10-C were also superior to the inoculation agents, indicating that T. reesei FS10-C was effective in enhancing both Cd phytoremediation by S. plumbizincicola and soil fertility. Furthermore, solid fermentation powder of FS10-C showed the greatest capacity to enhance plant growth, Cd uptake, nutrient release, microbial biomass and activities, as indicated by its superior ability to promote colonization by Trichoderma. The solid fermentation powder of FS10-C might serve as a suitable inoculation agent for T. reesei FS10-C to enhance both the phytoremediation efficiency of Cd-contaminated soil and soil fertility.

Time-dependent effect of graphene on the structure, abundance, and function of the soil bacterial community.

The increased application of graphene raises concerns about its environmental impact, but little information is available on the effect of graphene on the soil microbial community. This study evaluated the impact of graphene on the structure, abundance and function of the soil bacterial community based on quantitative real-time polymerase chain reaction (qPCR), pyrosequencing and soil enzyme activities. The results show that the enzyme activities of dehydrogenase and fluorescein diacetate (FDA) esterase and the biomass of the bacterial populations were transiently promoted by the presence of graphene after 4 days of exposure, but these parameters recovered completely after 21 days. Pyrosequencing analysis suggested a significant shift in some bacterial populations after 4 days, and the shift became weaker or disappeared as the exposure time increased to 60 days. During the entire exposure process, the majority of bacterial phylotypes remained unaffected. Some bacterial populations involved in nitrogen biogeochemical cycles and the degradation of organic compounds can be affected by the presence of graphene.

Evident bacterial community changes but only slight degradation when polluted with pyrene in a red soil.

Understanding the potential for Polycyclic aromatic hydrocarbons (PAH) degradation by indigenous microbiota and the influence of PAHs on native microbial communities is of great importance for bioremediation and ecological evaluation. Various studies have focused on the bacterial communities in the environment where obvious PAH degradation was observed, little is known about the microbiota in the soil where poor degradation was observed. Soil microcosms were constructed with a red soil by supplementation with a high-molecular-weight PAH (pyrene) at three dosages (5, 30, and 70 mg ⋅ kg(-1)). Real-time PCR was used to evaluate the changes in bacterial abundance and pyrene dioxygenase gene (nidA) quantity. Illumina sequencing was used to investigate changes in diversity, structure, and composition of bacterial communities. After 42 days of incubation, no evident degradation was observed. The poor degradation ability was associated with the stability or significant decrease of abundance of the nidA gene. Although the abundance of the bacterial 16S rRNA gene was not affected by pyrene, the bacterial richness and diversity were decreased with increasing dosage of pyrene and the community structure was changed. Phylotypes affected by pyrene were comprehensively surveyed: (1) at the high taxonomic level, seven of the abundant phyla/classes (relative abundance >1.0%) including Chloroflexi, AD3, WPS-2, GAL5, Alphaproteobacteria, Actinobacteria, and Deltaproteobacteria and one rare phylum Crenarchaeota were significantly decreased by at least one dosage of pyrene, while three phyla/classes (Acidobacteria, Betaproteobacteria, and Gammaproteobacteria) were significantly increased; and (2) at the lower taxonomic level, the relative abundances of twelve orders were significantly depressed, whereas those of nine orders were significantly increased. This work enhanced our understanding of the biodegradation potential of pyrene in red soil and the effect of pyrene on soil ecosystems at the microbial community level.

Rhizobia and their bio-partners as novel drivers for functional remediation in contaminated soils.

Environmental pollutants have received considerable attention due to their serious effects on human health. There are physical, chemical, and biological means to remediate pollution; among them, bioremediation has become increasingly popular. The nitrogen-fixing rhizobia are widely distributed in the soil and root ecosystems and can increase legume growth and production by supplying nitrogen, resulting in the reduced need for fertilizer applications. Rhizobia also possess the biochemical and ecological capacity to degrade organic pollutants and are resistant to heavy metals, making them useful for rehabilitating contaminated soils. Moreover, rhizobia stimulate the survival and action of other biodegrading bacteria, thereby lowering the concentration of pollutants. The synergistic action of multiple rhizobial strains enhances both plant growth and the availability of pollutants ranging from heavy metals to persistent organic pollutants. Because phytoremediation has some restrictions, the beneficial interaction between plants and rhizobia provides a promising option for remediation. This review describes recent advances in the exploitation of rhizobia for the rehabilitation of contaminated soil and the biochemical and molecular mechanisms involved, thereby promoting further development of this novel bioremediation strategy into a widely accepted technique.

[Ex-situ remediation of PAHs contaminated site by successive methyl-beta-cyclodextrin enhanced soil washing].

Polycyclic aromatic hydrocarbon (PAH) polluted sites caused by abandoned coking plants have attracted great attentions. This study investigated the feasibility of using methyl-beta-cyclodextrin (MCD) solution to enhance ex situ soil washing for extracting PAHs. Treatment with elevated temperature (50 degrees C) in combination with ultrasonication (35 kHz, 30 min) at 100 g x L(-1) was effective. It was found that 96.7% +/- 2.4% of 3-ring PAH, 89.7% +/- 3.2% of 4-ring PAH, 76.3% +/- 2.2% of 5 (+6)-ring PAH and 91.3% +/- 3.1% of total PAHs were removed from soil after five successive washing cycles. The desorption kinetics of PAHs from contaminated soil was determined before and after successive washings. The 400 h Tenax extraction of PAHs from soil was decreasing gradually with increasing washing times. Furthermore, the F(r), F(sl), k(r), k(sl) and k(vl) were significantly lower than those of CK (P < 0.01). Therefore, considering the removal efficiency and potential environmental risk after soil )ashing, successive washing three times was selected as a reasonable parameter. These results have practical implications for site risk assessment and cleanup strategies.

Soil contamination by phthalate esters in Chinese intensive vegetable production systems with different modes of use of plastic film.

The concentrations of six priority phthalic acid esters (PAEs) in intensively managed suburban vegetable soils in Nanjing, east China, were analyzed using gas chromatography-mass spectrometry (GC-MS). The total PAE concentrations in the soils ranged widely from 0.15 to 9.68 mg kg(-1) with a median value of 1.70 mg kg(-1), and di-n-butyl phthalate (DnBP), bis-(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DnOP) were the most abundant phthalate esters. Soil PAE concentrations depended on the mode of use of plastic film in which PAEs were incorporated as plasticizing agents and both the plastic film and poultry manure appeared to be important sources of soil PAEs. Vegetables in rotation with flooded rice led to lower concentrations of PAEs in soil. The results indicate that agricultural plastic film can be an important source of soil PAE contamination and further research is required to fully elucidate the mechanisms of PAE contamination of intensive agricultural soils with different use modes of use of plastic film.

[Optimizing remediation conditions of non-thermal plasma for DDTs heavily contaminated soil].

A series of experiments were carried out in a non-thermal reactor to remove DDTs in heavily contaminated soil by dielectric barrier discharge (DBD). The study aims to investigate the effects of soil properties (including soil particle size and soil water content) and equipment working parameters (e. g. the plasma power, the processing time and discharge atmosphere) on the removal of DDTs from soil. The results showed that DDTs in soil were significantly degraded by the non-thermal plasma produced by dielectric barrier discharge. Removal rate of DDTs increased with increasing processing time. The removal efficiency of DDTs ranged from 95.3% to 99.9% in 20 minutes. The optimum conditions were as follows: 1 kW of the plasma power, 20 minutes of processing time in air discharge atmosphere, 0-0.9 mm soil particle size and 4.5% -10.5% of soil moisture content. The results also showed that o,p'-DDE might be the intermediate dechlorination and dehydrogenation product of the o,p'-DDT after the oxidization.

Tenax TA extraction to understand the rate-limiting factors in methyl-ß-cyclodextrin-enhanced bioremediation of PAH-contaminated soil.

The effectiveness of many bioremediation systems for PAH-contaminated soil may be constrained by low contaminant bioaccessibility due to limited aqueous solubility or large sorption capacity. Information on the extent to which PAHs can be readily biodegraded is of vital importance in the decision whether or not to remediate a contaminated soil. In the present study the rate-limiting factors in methyl-ß-cyclodextrin (MCD)-enhanced bioremediation of PAH-contaminated soil were evaluated. MCD amendment at 10 % (w/w) combined with inoculation with the PAH-degrading bacterium Paracoccus sp. strain HPD-2 produced maximum removal of total PAHs of up to 35 %. The desorption of PAHs from contaminated soil was determined before and after 32 weeks of bioremediation. 10 % (w/w) MCD amendment (M2) increased the Tenax extraction of total PAHs from 12 to 30 % and promoted degradation by up to 26 % compared to 6 % in the control. However, the percentage of Tenax extraction for total PAHs was much larger than that of degradation. Thus, in the control and M2 treatment it is likely that during the initial phase the bioaccessibility of PAHs is high and biodegradation rates may be limited by microbial processes. On the other hand, when the soil was inoculated with the PAH-degrading bacterium (CKB and MB2), the slowly and very slowly desorbing fractions (F sl and F vl ) became larger and the rate constants of slow and very slow desorption (k sl and k vl ) became extremely small after bioremediation, suggesting that desorption is likely rate limiting during the second, slow phase of biotransformation. These results have practical implications for site risk assessment and cleanup strategies.

Remediation of polycyclic aromatic hydrocarbon and metal-contaminated soil by successive methyl-ß-cyclodextrin-enhanced soil washing-microbial augmentation: a laboratory evaluation.

Polycyclic aromatic hydrocarbon (PAH) and metal-polluted sites caused by abandoned coking plants are receiving wide attention. To address the associated environmental concerns, innovative remediation technologies are urgently needed. This study was initiated to investigate the feasibility of a cleanup strategy that employed an initial phase, using methyl-ß-cyclodextrin (MCD) solution to enhance ex situ soil washing for extracting PAHs and metals simultaneously, followed by the addition of PAH-degrading bacteria (Paracoccus sp. strain HPD-2) and supplemental nutrients to treat the residual soil-bound PAHs. Elevated temperature (50 °C) in combination with ultrasonication (35 kHz, 30 min) at 100 g MCD L(-1) was effective in extracting PAHs and metals to assist soil washing; 93 % of total PAHs, 72 % of Cd, 78 % of Ni, 93 % of Zn, 84 % of Cr, and 68 % of Pb were removed from soil after three successive washing cycles. Treating the residual soil-bound PAHs for 20 weeks led to maximum biodegradation rates of 34, 45, 36, and 32 % of the remaining total PAHs, 3-ring PAHs, 4-ring PAHs, and 5(+6)-ring PAHs after washing procedure, respectively. Based on BIOLOG Ecoplate assay, the combined treatment at least partially restored microbiological functions in the contaminated soil. The ex situ cleanup strategy through MCD-enhanced soil washing followed by microbial augmentation can be effective in remediating PAH and metal-contaminated soil.

[In-situ remediation of polychlorinated biphenyls polluted soil by ecological controlling measures: a field trial].

A field experiment was conducted to study the remediation of agricultural soils polluted with polychlorinated biphenyls (PCBs) by several ecological controlling measures. After sequential stages of liming, plowing, planting alfalfa and paddy, a significant part of PCBs was removed from the soil, with an average removal rate of 86.9%. The treatment also decreased the toxic equivalency of dioxin-like PCBs in soil. Analysis of PCB congener composition showed that at stages of liming, plowing and alfalfa planting, the low-chlorinated biphenyls were removed; whereas at the stage of paddy planting, the high-chlorinated biphenyls were degraded. The ecological controlling measures had little influence on the microbial communities in soil. The results suggest that ecological control techniques could be widely applied in the remediation of agricultural soils with PCBs contamination.