Effect of soil acidification induced by a tea plantation on chemical and mineralogical properties of Alfisols in eastern China.

The effect of a tea plantation on soil basic properties, chemical and mineralogical compositions, and magnetic properties of Alfisols from eastern China was studied. Under the tea plantation, acidification took place within a soil depth of 70 cm, with the maximum difference in pH in the upper 17 cm (ΔpH = 2.80). Both the tea plantation and unused soil profiles were predominated by free Fe and Al oxides, i.e. citrate/bicarbonate/dithionite extractable Fe (Fe(d)) and Al (Al(d)). Tea plantation soil was characterized by higher Al(d) and Fe(d) and lower Fe oxalate, Fe(2)O(3) and Al(2)O(3); CaO was depleted, whereas SiO(2) accumulated. Acidification induced by the tea plantation led to destruction of vermiculite followed by dissolution of the hydroxy-Al interlayers within its structure. The data clearly demonstrated that significant soil weathering occurred with acidification caused by tea cultivation. This acidification also resulted in decreased content of ferrimagnetic minerals due to the dissolution of minerals and movement of Fe in the profile.

[Study on the relationship between estrogen receptor beta and etiology of human endometrial polyps].

OBJECTIVE: To investigate the relationships between the expression of estrogen receptor beta (ERbeta) and etiology of human endometrial polyps (EP). METHODS: Thirty-six females with infertility and 36 females with intrauterine contraceptive device (IUD, aged from 23 years to 33 years, average 28 years) were enrolled in the study. Blood samples were taken before hysteroscopy for analysis of the level of estradiol in serum. All the tissue samples of benign EP and endometrium in the same cycle were obtained through hysteroscopy on the 5th to 9th days of menstruation cycle (all the women selected had the same menstrual period). Part of the samples of EP were made into homogenates to assay the level of estradiol, and the rest of EP and endometrium were both fixed with 10% formalin. If one of the samples was confirmed by histopathologic analysis, the correspondence was eligible. Otherwise, they were abnegated. Seventy-two samples were collected and 60 were eligible as a result. The expression of ERbeta and ERalpha in these samples was detected by immunohistochemical staining, while the levels of estradiol in both serum and homogenate of EP were detected by radioimmunoassay. RESULTS: The expression of stromal ERbeta of EP in infertility and IUD groups (2.1 +/- 0.9, 1.9 +/- 0.5) was significantly higher than those of endometrium in the same cycle (1.7 +/- 0.3, 1.3 +/- 1.1) (P < 0.05), while the expression of stromal ERalpha of EP was significantly decreased than those of endometrium (P > 0.05). The expression of ERbeta in glands had no difference in both EP and endometrium. The expression of ERbeta was significantly positively related to the levels of estradiol in both serum and homogenate (P < 0.01), while the expression of ERalpha had no correlation with estradiol. CONCLUSIONS: Overexpression of ERbeta in stroma might play an important role in the pathogenesis of EP.

Effect of biochars on adsorption of Cu(II), Pb(II) and Cd(II) by three variable charge soils from southern China.

The purpose of this study is to compare the relative contribution of different mechanisms to the enhanced adsorption of Cu(II), Pb(II) and Cd(II) by variable charge soils due to incorporation of biochars derived from crop straws. The biochars were prepared from the straws of canola and peanut using an oxygen-limited pyrolysis method at 350 °C. The effect of biochars on adsorption and desorption of Cu(II), Pb(II) and Cd(II) by and from three variable charge soils from southern China was investigated with batch experiments. Based on the desorption of pre-adsorbed heavy metals, the electrostatic and non-electrostatic adsorptions were separated. EDTA was used to replace the heavy metals complexed with biochars and to evaluate the complexing ability of the biochars with the metals. The incorporation of biochars increased the adsorption of Cu(II), Pb(II) and Cd(II) by the soil; peanut straw char induced a greater increase in the adsorption of the three metals. The increased percentage of Cd(II) adsorption induced by biochars was much greater than that for the adsorption of Cu(II) and Pb(II). Cu(II) adsorption on three variable charge soils was enhanced by the two biochars mainly through a non-electrostatic mechanism, while both electrostatic and non-electrostatic mechanisms contributed to the enhanced adsorption of Pb(II) and Cd(II) due to the biochars. Peanut straw char had a greater specific adsorption capacity than canola straw char and thus induced more non-electrostatic adsorption of Cu(II), Pb(II) and Cd(II) by the soils than did the canola straw char. The complexing ability of the biochars with Cu(II) and Pb(II) was much stronger than that with Cd(II) and thus induced more specific adsorption of Cu(II) and Pb(II) by the soils than that of Cd(II). Biochars increased heavy metal adsorption by the variable charge soils through electrostatic and non-electrostatic mechanisms, and the relative contribution of the two mechanisms varied with metals and biochars.

[Adsorption of methylene blue from water by the biochars generated from crop residues].

Biochars were prepared from straws of rice, peanut and soybean and rice hull using a low temperature pyrolysis method and adsorption of methylene blue by these biochars were investigated with batch and leaching experiments. Results indicated that biochars have high adsorption capacity for methylene blue and followed the order: rice straw char > soybean straw char > peanut straw char > rice hull char. This order is generally consistent with the amount of negative charge and specific surface area of these biochars. While methylene blue was mainly adsorbed specifically by the biochars, because the adsorption of methylene blue increased with the increase of ionic strength and the adsorption led to the shift of zeta potential of biochar particles to positive value direction. Langmuir equation fitted the adsorption isotherms well and can be used to describe the adsorption behaviors of methylene blue by the biochars. The maximum adsorption capacity of methylene blue predicted by langmuir equation was 196.1, 169.5, 129.9 and 89.3 mmol x kg(-1) for rice straw char, soybean straw char, peanut straw char and rice hull char, respectively. Leaching experiments show that rice hull char of 156 g can remove methylene blue from 30 L water containing 0.3 mmol x L(-1) of methylene blue completely and the cumulative amount of methylene blue absorbed by the biochar reaches 57.7 mmol x kg(-1). The biochars can be used as efficient adsorbents to remove methylene blue from waste water of dye.

Adsorption of methyl violet from aqueous solutions by the biochars derived from crop residues.

The adsorption of methyl violet by the biochars from crop residues was investigated with batch and leaching experiments--adsorption capacity varied with their feedstock in the following order: canola straw char>peanut straw char>soybean straw char>rice hull char. This order was generally consistent with the amount of negative charge of the biochars. Zeta potentials and Fourier transform infrared photoacoustic spectroscopy, combined with adsorption isotherms and effect of ionic strength, indicated that adsorption of methyl violet on biochars involved electrostatic attraction, specific interaction between the dye and carboxylate and phenolic hydroxyl groups on the biochars, and surface precipitation. Leaching experiments showed that 156 g of rice hull char almost completely removed methyl violet from 18.2 L of water containing 1.0 mmol/L of methyl violet. The biochars had high removal efficiency for methyl violet and could be effective adsorbents for removal of methyl violet from wastewater.