Xue Ying Song

Long-Term Phytoremediation Process of Diesel Oil-Contaminated Soil

Soils contaminated with diesel oil were remediated with alfalfa (Medicago sativa) by outdoor pot experiment over a 5-growth season treatment, with pollutant levels, special microbial inoculators, fungi inoculators, and organic manure as control factors. The dynamics of residual concentrations of mineral oil and PAHs in soil of different phytoremediation treatments during the 5 seasons were determined. Results showed that significant reduction of contaminant concentration was achieved. At the end of the fifth growth season, initial concentrations of mineral oil were reduced by 96.5% to 98.8% in the phytoremediat treatments. Among the four factors, bacterial and fungi inoculators showed no significant effect on the contaminant removal in the process of long-term bioremediation. Effect of organic fertilizer amendments differed depending on the diesel concentration. In the highly contaminated treatments (15000 and 30000 mg/kg dry weight) remarkable stimulation was detected with the increase of fertilizer amendment; however, the trend was just reversed in the lightly contaminated treatments (5000 mg/kg dry weight) with the increase of manure amendment.

Remediation of Cadmium Contamination in Soil by Washing

Soil washing is a possible remediation technique for contaminant extracting from the soil. Thiacalix[4]arenetetrasulfonate has become an alternative to metal extractants due to its high selectivity and high stability. Batch soil-washing experiments were conducted to investigate the effect of pH on extraction efficiency of Cd from soil by the thiacalix[4]arenete-trasulfonate solution. Results showed that more than 82 percent of cadmium was extracted by the thiacalix[4]arenetetra- sulfonate solution from the artificially contaminated soil with the concentration of 562 mg/kg cadmium at the initial pH value of 11. Thiacalix[4]arenetetrasulfonate could be an attractive alternative in washing remediation of soil contaminated by Cd.

Seasonal Variations of the Regular Indices of the Surface Water in the Taizi River

The regular indices of the surface water of the Taizi River, Liaoning Province, northeast of China, were investigated. Samples were collected from upstream to downstream locations of the mainstream, and also from the tributaries of the Taizi River in dry season, wet season, and normal season, respectively. The DO values of the surface water ranged from 3.35 mg/L to 18.73 mg/L, 0.09 mg/L to 13.44mg/L, and 3.49 mg/L to 16.9 mg/L, respectively, in the dry season, wet season, and normal season, respectively. The seasonal variations of the pH values of the surface water were in the order of dry season >wet season >normal season.

Spatial Distribution and Seasonal Variations of Heavy Metals in Surface Water of the Taizi River

The contamination levels and distribution of heavy metals in surface water of the Taizi River were investigated. Samples of water were collected from upstream to downstream locations, and also from the main tributaries of the Taizi River. All samples were analyzed for arsenic, mercury, and chromium (Ⅵ). Results indicated that the metal levels of upriver sites were lower than downriver sites. The total concentrations of Cr6+ and As in dry season was higher than that in flood season. While heavy metal Hg represents the highest concentration in flood season. Compared with the permissible levels of surface water environmental quality standards (GB3838-2002), the levels of Cr6+ and As attained the first and second level, but Hg attained the fifth level. This indicated that most sites of the Taizi River have a high risk of Hg pollution in flood period.

Study on the Contamination of NH3-N and Total Phosphorus in the Seasonal River

Water samples were collected from the upstream to the downstream of a seasonal river, the Taizi River, and its main tributaries in dry season, normal season, and wet season. The variations of NH3-N, and total phosphorus (TP) within a hydrological year were analyzed, aimed to study the pollution characteristics and sources of the water bodies. It was found that the tributaries of the Taizi River were heavily contaminated by NH3-N, with 83.8%, 100% and 100% of the sampling sites exceeding the fifth level in the dry season, wet season and normal season, respectively. The concentration of TP in the dry season fluctuated wildly, which was much higher than those in the wet and normal season. Compared with the permissible levels set by the environmental quality standards for surface water standard (GB3838-2002) of China, 57.1% of the sampling sites in the main stream and tributaries of the Taizi River belong to the fifth level or exceed the fifth level in the dry season, and only 7.1% of the sampling sites were belonging to the fifth level or exceed the fifth level in the wet and normal season. Overall, the waterbody of Taizi River was more seriously polluted by urban domestic sewage and point source of industrial wastewater.

Effect of Mushroom Residue Used in Washed Soil on the Growth of Tomatoes

In order to reveal the regulating capacity of mushroom residue on washed soil, pots experiments were carried out. The growth of tomatoes planted on washed soil amended by mushroom residue were measured. Mushroom residue can be helpful to improve the plant height, stem diameter, the aerial parts fresh weight, root fresh weight, leaf photosynthetic rates and photosynthesis, and lay a good foundation for the growth of tomatoes. The effect of mushroom residue is the most significant. Among all the treatments of adding 2.5%, 5%, 10% mushroom residue, adding 10% mushroom residue is the best. It can significantly enhance the growth and photosynthesis of tomatoes, and is among the best of these three soil treatments for washed soil.

Spatial Distribution and Seasonal Variations of Volatile Phenols in the Surface Water of the Taizi River

Concentrations, spatial distribution, seasonal distribution of volatile phenols were investigated in the surface water of the Taizi River in Liaoning Province, northeast of China. Samples were collected from upstream to downstream locations of the mainstream, and also from the tributaries of the Taizi River in dry season, wet season, and normal season, respectively. Five important industrial point sources were also monitored. The volatile phenol concentrations in the mainstream and tributaries ranged from 0.001 to 0.055 mg/L in the dry season, 0.010 to 0.120 mg/L in the wet season, and 0.010 to 0.56 mg/L in the normal season. The average concentrations of volatile phenol in the surface water increased by the order of dry season > normal season > wet season. The concentrations of volatile phenols were correlated significantly among the three seasons (p< 0.05).

Composting Study of Petroleum Contaminated Soil

Composting has been shown to be an effective bioremediation technique for the treatment of hydrocarbon-contaminated soil. In this research, the major objective of this research was to find the appropriate mix ratio of organic amendments for enhancing the degradation of petroleum hydrocarbons during diesel oil contaminated soil composting. The spent mushroom was added as an amendment for supplementing organic matter for composting of contaminated soil. The volumn ratios of contaminated soil to organic amendments were 1:1, 1.5:1 and 2:1. Target contaminant of this research was diesel oil, which was spiked at 16240 mg/kg sample on a dry weight basis. The degradation of diesel oil was significantly enhanced by the addition of these organic amendments relative to straight soil control. Degradation rates of total petroleum hydrocarbons (TPH) were the greatest at the ratio of 1:1 of contaminated soil to organic amendments on the volumn ratio. The abiotic loss of TPH was only about 6.83% of initial TPH.

Cadmium Migration and Distribution Process

The significant pollution accidents which not only threaten public health and public property safety, but also bring major disaster, have become the world concerning environmental problems. The migration process and feature of CdCl2 in the vertical and horizontal profiles of soil were studied by the stimulating experiment to present the theory for the treatment of significant pollution accident. The column leaching device was taken to simulate the vertical and horizontal migration of CdCl2 in the soil profile under two-phase rainfall during 16 days. The portable manual control negative pressure pump was taken to extract soil solution sample and the CdCl2 concentration was determined by the atomic absorption spectrophotometer. Results showed that during the whole experiment, the obvious horizontal and vertical migration features of CdCl2 appeared. The CdCl2 covered the whole horizontal profile in 0.5 h and the whole vertical profile in 146 hours. The relative variation rate of CdCl2 in the different depth of bulk showed that the rapid passing time differed in the different depths. The simulating device used in this paper could well investigate the vertical and horizontal distribution and migration of contaminant. Under the condition of greater rainfall, the CdCl2 gave priority to the horizontal runoff in the surface soil, followed by the vertical migration.

Joint Effect of Cadmium and Chlorimuron-Ethyl on Cadmium Accumulation of Wheat

The joint effects of Cd and Chlorimuron-ethyl(CE) on Cd accumulation in wheat shoot/root and SPT coefficient of Cd was carried out. Cd concentration in shoot and root increased with increasing soil Cd, but Cd concentration in shoot/root was lower than the same treatment when CE was added, and negative relationship between Cd concentration in shoot (root) and concentration of CE were significant (p<0.05 or p<0.01). There was antagonistic effect of Cd and low CE on Cd accumulation in wheat tissues. Cd concentration in shoot decreased during the period of growth, but the concentration of Cd in root increased from the elongation stage to the florescence, and then decreased from the florescence to mature stage when the concentration of soil Cd was less than 100 mg kg-1, and it decreased when the concentration of soil Cd was 100 mg kg-1. The SPT values of different growth periods decreased during the period of growth.