Enantioselective aquatic toxicity of current chiral pesticides

Chiral pesticides are ubiquitous in the aquatic environment, and their enantioselectivities in aquatic toxicity are known to be complicated. The difference in enantioselective effects between enantiomers may sometimes differ by approximately 100-fold or more, which makes it important to incorporate enantioselective effects into the risk assessment of chiral pesticides. In this paper, we reviewed relevant work on the aquatic toxicity of chiral pesticides with an emphasis on the enantioselective aquatic toxicity under both chronic and acute exposure conditions. We provided a personal account of the importance of studies on molecular mechanisms of developmental toxicity and specific endpoints such as vitellogenin, yolk sac edema and pericardial edema in future research. Given the widespread use of chiral pesticides, we suggest that a more comprehensive understanding of the significance of enantioselective aquatic toxicity will be very helpful in improving risk assessment and regulation of chiral pesticides.     

Chemical compositions and sources of atmospheric PM10 in heating, non-heating and sand periods at a coal-based city in northeastern China

Mass concentrations and chemical components (18 elements, 9 ions, organic carbon [OC] and elemental carbon [EC]) in atmospheric PM(10) were measured at five sites in Fushun during heating, non-heating and sand periods in 2006-2007. PM(10) mass concentrations varied from 62.0 to 226.3 μg m(-3), with 21% of the total samples' mass concentrations exceeding the Chinese national secondary standard value of 150 μg m(-3), mainly concentrated in heating and sand periods. Crustal elements, trace elements, water-soluble ions, OC and EC represented 20-47%, 2-9%, 13-34%, 15-34% and 13-25% of the particulate matter mass concentrations, respectively. OC and crustal elements exhibited the highest mass percentages, at 27-34% and 30-47% during heating and sand period. Local agricultural residuals burning may contribute to EC and ion concentrations, as shown by ion temporal variation and OC and EC correlation analysis. Heavy metals (Cr, Ni, Zn, Cu and Mn) from coal combustion and industrial processes should be paid attention to in heating and sand periods. The anion/cation ratios exhibited their highest values for the background site with the influence of stationary sources on its upper wind direction during the sand period. Secondary organic carbon were 1.6-21.7, 1.5-23.0, 0.4-17.0, 0.2-33.0 and 0.2-21.1 μg m(-3), accounting for 20-77%, 44-88%, 4-77%, 8-69% and 4-73% of OC for the five sampling sites ZQ, DZ, XH, WH and SK, respectively. From the temporal and spatial variation analysis of major species, coal combustion, agricultural residual burning and industrial emission including dust re-suspended from raw material storage piles were important sources for atmospheric PM(10) in Fushun at heating, non-heating and sand periods, respectively. It was confirmed by principal component analysis that coal combustion, vehicle emission, industrial activities, soil dust, cement and construction dust and biomass burning were the main sources for PM(10) in this coal-based city.     

Determination of total petroleum hydrocarbons (TPH) in agricultural soils near a petrochemical complex in Guangzhou,China

The total petroleum hydrocarbons (TPH) pollution in regional agricultural soils was investigated. Seventy soil samples collected from surface layers (0–20 cm) and horizons of five selected pedons in the vicinity of a petrochemical complex in Guangzhou, China were analyzed, and the vertical variation and spatial variability of TPH were evaluated. The TPH concentration in top soils around the petrochemical complex ranged from 1,179.3 to 6,354.9 mg kg^− 1, with the average of 2,676.6 mg kg^− 1. Furthermore, significant differences between land-use types showed that the TPH concentration in top soils was strongly influenced by accidental spills. Both the TPH trends in pedons and the identified hot-spot areas also showed that the accidental explosions or burning accidents were mainly responsible for the pollution. The results reported here suggest that the regular monitoring and inspection shall be conducted for safety and to avoid or minimize the accidents, and the effective measures should be taken to remediate the contaminated areas and to assure that the important industrialization of Guangzhou area would not mean human health risks near the petrochemical complex.     

Racemic,R-, and S-tebuconazole altered chitinase and chitobiase activity of Daphnia magna

Tebuconazole is a chiral trizole fungicide and widely used in many crops for controlling disease. Tebuconazole is potential toxic to some aquatic organisms but relative information of its isomers is scarce. To detect the endocrine disrupting effects and difference of rac-, R-, and S-tebuconazole, the chitinase activity in Daphnia magna and chitobiase activity in each test medium were used as biomonitors after a 14-day exposure. Results showed that chitinase activity was significantly reduced by rac-, R-, and S-tebuconazole. The chitobiase activity in the test medium was reduced by rac- and R-tebuconazole before day 10, and only one peak was observed at day 10 or day 12 compared with two obvious peaks in the control group (days 6 and 12). S-tebuconazole delayed and reduced the reproduction of D. magna, but did not delay the first chitobiase activity peak, whereas the second peak could not be characterized as the exposure concentration and time increased. Compared with chitinase activity, chitobiase activity can still be used as a rudimentary model for identifying molt-interfering xenobiotics, and further studies should focus on the analysis of correlations between these parameters.     

Spatial distribution characteristics of soil organic carbon in subtropical forests of mountain Lushan,China

The study on the spatial distribution of forest soil organic carbon (SOC) is of great significance for accurate assessment of carbon storage in forest ecosystems. In the present study, by taking eight kinds of forest soils of Mountain Lushan in the subtropical area as the research object, we studied the spatial distribution characteristics of SOC in this mountainous area. The results showed that the SOC content and SOC density (SOCD) of main forest types in the Mountain Lushan were lower than the national and the world average. The soil layer of Lushan forest was thinner, and the SOC and active SOC (ASOC) contents of different forest types and SOCDs are the highest in the surface soil. SOCD of the topsoil accounts for 32.64–54.03% of the total SOCD in the whole soil profile. Surface litter is an important source of SOC, and the different vegetation types are the important reason for the different spatial distribution of SOC in this area. Soil SOC contents in the high-altitude forest (bamboo forest, deciduous broadleaf forest, Pinus taiwanensis forest, evergreen-deciduous forest, and coniferous-broadleaved mixed forest) were higher than those in the low-altitude forest (evergreen broadleaf forest, shrub, and Pinus massoniana forest). However, the difference in SOC content exhibited at the altitude gradient is significantly lower than that in SOC in the soil profile. This indicates that both soil depth and elevation are the important factors that affected SOC distribution. However, the influence of soil depth on spatial distribution of SOC may be more complex than that of altitude. Vegetation types and soil properties are the main reasons for the large differences of reduction rate in the contents of SOC and ASOC.     

A mini review of fluoride-induced apoptotic pathways

Fluorine or fluoride can have toxic effects on bone tissue and soft tissue at high concentrations. These negative effects include but not limited to cytotoxicity, immunotoxicity, blood toxicity, and oxidative damage. Apoptosis plays an important role in fluoride-induced toxicity of kidney, liver, spleen, thymus, bursa of Fabricius, cecal tonsil, and cultured cells. Here, apoptosis activated by high level of fluoride has been systematically reviewed, focusing on three pathways: mitochondrion-mediated, endoplasmic reticulum (ER) stress-mediated, and death receptor-mediated pathways. However, very limited reports are focused on the death receptor-mediated apoptosis pathways in the fluoride-induced apoptosis. Therefore, understanding and discovery of more pathways and molecular mechanisms of fluoride-induced apoptosis may contribute to designing measures for preventing fluoride toxicity.     

The regulatory role of endogenous iron on greenhouse gas emissions under intensive nitrogen fertilization in subtropical soils of China

Environmental Science and Pollution Research - Anaerobic batch experiments were conducted to study the regulatory role of endogenous iron in greenhouse gas emissions under intensive nitrogen...     

Soil surface Hg emission flux in coalfield in Wuda,Inner Mongolia,China

Hg emission flux from various land covers, such as forests, wetlands, and urban areas, have been investigated. China has the largest area of coalfield in the world, but data of Hg flux of coalfields, especially, those with coal fires, are seriously limited. In this study, Hg fluxes of a coalfield were measured using the dynamic flux chamber (DFC) method, coupled with a Lumex multifunctional Hg analyzer RA-915+ (Lumex Ltd., Russia). The results show that the Hg flux in Wuda coalfield ranged from 4 to 318 ng m^?2 h^?1, and the average value for different areas varied, e.g., coal-fire area 99 and 177 ng m^?2 h^?1; no coal-fire area 19 and 32 ng m^?2 h^?1; and backfilling area 53 ng m^?2 h^?1. Hg continued to be emitted from an underground coal seam, even if there were no phenomena, such as vents, cracks, and smog, of coal fire on the soil surface. This phenomenon occurred in all area types, i.e., coal-fire area, no coal-fire area, and backfilling area, which is universal in Wuda coalfield. Considering that many coalfields in northern China are similar to Wuda coalfield, they may be large sources of atmospheric Hg. The correlations of Hg emission flux with influence factors, such as sunlight intensity, soil surface temperature, and atmospheric Hg content, were also investigated for Wuda coalfield.

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Effects of coal spoil amendment on heavy metal accumulation and physiological aspects of ryegrass (<Emphasis Type="Italic">Lolium perenne</Emphasis> L.) growing in copper mine tailings

Copper mine tailings pose many threats to the surrounding environment and human health, and thus, their remediation is fundamental. Coal spoil is the waste by-product of coal mining and characterized by low levels of metals, high content of organic matter, and many essential microelements. This study was designed to evaluate the role of coal spoil on heavy uptake and physiological responses of Lolium perenne L. grown in copper mine tailings amended with coal spoil at rates of 0, 0.5, 1, 5, 10, and 20%. The results showed that applying coal spoil to copper mine tailings decreased the diethylenetriaminepentaacetic acid (DTPA)-extractable Cd, Cu, Pb, and Zn contents in tailings and reduced those metal contents in both roots and shoots of the plant. However, application of coal spoil increased the DTPA-extractable Cr concentration in tailings and also increased Cr uptake and accumulation by Lolium perenne L. The statistical analysis of physiological parameters indicated that chlorophyll and carotenoid increased at the lower amendments of coal spoil followed by a decrease compared to their respective controls. Protein content was enhanced at all the coal spoil amendments. When treated with coal spoil, the activities of superoxide dismutases (SOD), peroxidase (POD), and catalase (CAT) responded differently. CAT activity was inhibited, but POD activity was increased with increasing amendment ratio of coal spoil. SOD activity increased up to 1% coal spoil followed by a decrease. Overall, the addition of coal spoil decreased the oxidative stress in Lolium perenne L., reflected by the reduction in malondialdehyde (MDA) contents in the plant. It is concluded that coal spoil has the potential to stabilize most metals studied in copper mine tailings and ameliorate the harmful effects in Lolium perenne L. through changing the physiological attributes of the plant grown in copper mine tailings.     

加速溶剂萃取-固相萃取/超高效液相色谱-串联质谱法测定沉积物中5种微囊藻毒素

建立了加速溶剂萃取-固相萃取/超高效液相色谱-串联质谱法同时测定沉积物中5种微囊藻毒素(MC-LR、MC-RR、MC-LW、MC-LF、MC-YR)的方法。选择甲醇-水(1∶4,V/V)为ASE萃取溶剂,萃取温度和萃取压力分别为80℃和13.1 MPa,固相萃取过程以HLB小柱为萃取柱,采用液相色谱-串联质谱分析。方法在5种微囊藻毒素质量浓度5~100μg/L内线性良好(r0.995),回收率为76.0%~118%,相对标准偏差为1.9%~12.0%,检出限为2~3μg/kg,定量下限为8~12μg/kg。该方法已用于西太湖沉积物的检测,具有较好的方法适用性。