Effects of the Interactions Between Selenium and Phosphorus on the Growth and Selenium Accumulation in Rice (Oryza Sativa)

The solution culture, paddy soil culture and the simulation experiments in the laboratory were conducted to clarify the interactions between selenium and phosphorus, and its effects on the growth and selenium accumulation in rice. Results revealed that a suitable supply of selenium could promote rice growth and excessive selenium could injure rice plant, causing lower biomass, especially in the roots. The supply of selenite could enhance the selenium contents of rice shoots and roots in solution culture and in soil culture. The selenium concentrations in roots were much higher than those in shoots supplied with the same rates of selenium and phosphorus. The interaction between selenium and phosphorus was evident. When the phosphorus supply increased to meet the needs of plant growth, phosphorus could promote absorption and accumulation of selenium in the shoots. If the phosphorus supply was excessive, phosphorus could inhibit the accumulation of selenium in the shoots at the lower selenite level (2 mol l^–1), but could not at the higher selenite level (10 mol l^–1). With the supply of phosphate increased, the selenium concentrations in the roots decreased significantly at both selenite levels. The presence of phosphate could decrease Se sorption on the soil surface and increase the selenium concentration in the soil solution. The concentrations of selenium in shoots and roots supplied with 0.08 g kg^–1 phosphorus were lower than those with no phosphorus supplied. With the increase of phosphorus added to 0.4 g kg^–1, the selenium concentration in shoots and roots increased. The effect of phosphorus on the concentration was statistically significant at all three selenium levels.     

Environmental and Biological Monitoring of Organochlorine Residues after the Plague Epidemic in Surat, India - A Preliminary Study

In late August 1994, an outbreak of human pneumonic/bubonic plague was reported in Surat, India. During the epidemic, large amounts of pesticides, such as benzene-hexachloride (BHC) and other organochlorinated compounds were used to control the vector that might have transmitted the plague. In order to evaluate the extent of contamination, both environmental samples (9 water samples and 4 soil samples) and biological samples (5 blood and urine samples) were collected and analyzed for organochlorine residues. Samples were analyzed after hexane extraction by gas chromatography equipped with electron capture detector (GC-ECD), using a PTE-5 capillary column. The results showed that the levels of 1,1-(2,2-dichloroethenylidene)-bis[4-chlorobenzene] (DDE), a major metabolite of DDT, were low in environmental samples (water, soil), while BHC levels were relatively high in one of the water sample as well as two soil samples. The BHC and DDE levels in the biological samples were not higher than those reported earlier from India, except for serum DDE. Further studies are needed to evaluate the effect of long-term exposure as the present study was based on limited samples.     

Cause of PM2.5 pollution during the 2016-2017 heating season in Beijing, Tianjin, and Langfang, China

To investigate the cause of fine particulate matter (particles with an aerodynamic diameter less than 2.5 µm, PM_2.5) pollution in the heating season in the North China Plain (specifically Beijing, Tianjin, and Langfang), water-soluble ions and carbonaceous components in PM_2.5 were simultaneously measured by online instruments with 1-hr resolution, from November 15, 2016 to March 15, 2017. The results showed extreme severity of PM_2.5 pollution on a regional scale. Secondary inorganic ions (SNA, i.e., NO₃^?+SO₄²+ NH₄⁺) dominated the water-soluble ions, accounting for 30%-40% of PM_2.5, while the total carbon (TC, i.e., OC + EC) contributed to 26.5%-30.1% of PM_2.5 in the three cities. SNA were mainly responsible for the increasing PM_2.5 pollution compared with organic matter (OM). NO₃^? was the most abundant species among water-soluble ions, but SO₄^2- played a much more important role in driving the elevated PM_2.5 concentrations. The relative humidity (RH) and its precursor SO₂ were the key factors affecting the formation of sulfate. Homogeneous reactions dominated the formation of nitrate which was mainly limited by HNO₃ in ammonia-rich conditions. Secondary formation and regional transport from the heavily polluted region promoted the growth of PM_2.5 concentrations in the formation stage of PM_2.5 pollution in Beijing and Langfang. Regional transport or local emissions, along with secondary formation, made great contributions to the PM_2.5 pollution in the evolution stage of PM_2.5 pollution in Beijing and Langfang. The favourable meteorological conditions and regional transport from a relatively clean region both favored the diffusion of pollutants in all three cities.     

Rapid growth of environmental research in China

正Environmental research in China has grown tremendously over the last thirty years.This rapid and sustained growth has been supported by the remarkable increases in research funding,the number of graduate students,the degree-offering programs in environmental sciences and engineering,the state-of-the-art facilities,and international collaboration.In 1986 when the National Natural Science Foundation of     

Professor William R. Cullen and arsenic chemistry

正This special issue of the Journal of Environmental Sciences honors Professor William R.Cullen for his outstanding contributions to synthetic chemistry,environmental chemistry,microbiology,and toxicology of arsenic and its compounds.It is very fitting that the papers in this issue cover a diverse range of topics of arsenic     

Wet Strength and Water Resistance of Modified Soy Protein Adhesives and Effects of Drying Treatment

Soy protein isolate (SPI) was modified using sodium dodecyl sulfate (SDS) and guanidine hydrochloride (GuHCl). Adhesion performance of the modified SPI on fiberboard was studied. The Water-soluble mass of the modified SPI adhesives was examined following modified ASTM D5570. The SDS-modified SPI containing 91% protein had a water-soluble mass of 1.7%. To be considered a water-resistant adhesive, the water-soluble mass of adhesive should be less than 2%. The wet shear strength test showed 100% cohesive failure within fiberboard, indicating that the modified SPI has good water resistance. The effect of drying treatment on adhesion performance of the SDS-modified SPI on fiberboard was then investigated. Drying treatment significantly affected the final adhesion performance. Shear strength did not change much, but the percentage of cohesive failure within fiberboard increased markedly as drying temperature increased. All the unsoaked, soaked, and wet specimens glued by the adhesives treated at 70° or 90°C had 100% cohesive failure within fiberboard. Viscosity also increased greatly with an increase in drying temperature. This information will be useful in developing low-cost adhesive processing system in the future.     

Diffusion of ISO 14001 environmental management systems in China: rethinking on stakeholders’ roles

Since the release of ISO 14001 in 1996, China has witnessed a surge in the number of ISO 14001 certification. As an international environmental standard, ISO 14001 has two basic functions: one is playing as an environmental management instrument, while the other as a signal of firms’ better environmental performance to stakeholders. Based on the stakeholder theory, we have examined the effects of community, regulatory and some organizational stakeholders on the diffusion of ISO 14001 certification at Chinese provincial levels. Using a panel data of ISO 14001 certification from each province for the period of 2004-2008 in China, empirical evidence of such relations is found. The finding reveals that signaling to foreign customers and community stakeholders plays a dominant role in encouraging diffusion of ISO 14001 certification. However, as an important organizational stakeholder, foreign investors have shown no significant effect on the diffusion of ISO 14001 in China.     

Toxicity of copper, lead, and cadmium on the motility of two marine microalgae Isochrysis galbana and Tetraselmis chui

Computer assisted movement tracking was used to characterize the motility of two marine microalgae, Isochrysis galbana and Tetraselmis chui, and to investigate the toxicity of Cu, Pb, and Cd on motile percentage, curvilinear velocity, average path velocity, straight line velocity, linearity, straightness, and wobble. Except for motile percentage, all other motility parameters di ered significantly between I. galbana and T. chui. Based on relative motile percentage data, the median e ective concentration (EC50) of Cu on the motility of I. galbana and T. chui was 31.4 and 1.3 mol/L, respectively, while for Pb it was 37.8 and 10.9 mol/L and for Cd it was 121.6 and 37.8 mol/L, respectively. Compared to I. galbana, T. chui was more sensitive to all tested metals. The toxic e ect of the heavy metals on motility exhibited the following decreasing order for both species: Cu > Pb > Cd. Our results indicate that I. galbana and T. chui motility is sensitive to heavy metals and can be used as an indicator for toxicology bioassays.