水分管理对重金属在水稻根区及在水稻中积累的影响

选取了酸性矿山废水污灌区重金属污染水稻土,通过盆栽试验,研究了不同水分管理条件（60%最大田间持水量,80%最大田间持水量,最大田间持水量,前期淹水＋抽穗扬花期烤田,全生育期淹水）下水稻根际土壤及其不同器官（稻根、茎叶和籽粒）中As、Cd、Cu和Zn的含量变化。结果表明：土壤水分含量对水稻根际土壤中As、Cu和Zn的含量影响不大。但显著影响水稻不同器官对这3种元素的吸收积累。随着土壤水分含量的增加,水稻根、茎叶和籽粒中As的含量都显著增加;Cu的含量则逐渐减少;水稻茎叶中Zn含量也逐渐减少,但水稻根和籽粒中Zn含量则变化不明显。抽穗扬花期拷田能显著降低As在水稻中的积累,显著增加水稻茎叶中Zn的积累;但不影响水稻各器官中Cu,以及水稻根和籽粒中Zn的含量。此外,虽然这3种重金属在土壤中含量均超标,但在水稻籽粒中含量只有Zn全部超标,而Cu则都不超标,因此,农作物的超标情况并不直接与土壤的重金属超标相联系。     

高硫高铁土壤全硫提取和测定方法的改进

硫酸钡分光光度比浊法是大批量测定土壤环境样品硫含量的常用方法,但影响测定结果的因素较多,如稳定剂的选择、酸度的控制、BaCl：的形态和用量等均可对测定结果产生影响。在多金属硫化物矿区,由于长期的采矿冶炼活动,造成周边土壤中硫、铁含量增加,用比浊法测定硫含量时,铁的含量也对测定结果产生显著影响。针对这些影响因素,本研究在用硝酸．高氯酸湿法对土壤进行消解后,优化了硫酸钡分光光度比浊法测定高硫高铁样品的实验条件和实验步骤,并对多金属硫化物矿区的土壤样品进行了测定,得到了较好的结果。实验证明,称取0．50g土壤样品,消解后过滤,取滤液7mL,加入1mL研（1＋2）甘油．乙醇]=6％的甘油．乙醇为稳定剂,1mL浓磷酸掩蔽Fe3＋与cl-反应所显的黄色,定容到10mL,加入w（BaCl2）=10％的氯化钡溶液10mL,电磁搅拌1min,静置20-40min,在波长440nm处,比浊法测定土壤全硫含量,相对误差〈10％,取得良好的测定结果。此方法简单、快捷、方便,适合大批量环境样品的测定。     

广东采石场的特点及复绿方法选用

通过对广东省采石场的调查,阐述了采石场高、陡、缺土、缺水、生境恶劣等特点.提出了采石场复绿点、线、面种植复绿的三大类方法,并对各种方法所对应的坡面地质条件作出了论述.同时提出了复绿的各种配套措施,包括给排水、植物配置、种植土配制等.     

Longitudinal increases in PCDD/F and dl-PCB concentrations in human milk in northern China

There is a dearth of information on the temporal changes in polychlorinated dibenzodioxin/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) contamination, in both environmental and biological specimens, in China. We compared the concentrations of PCDD/Fs and dl-PCBs in human milk collected in Shijiazhuang, Hebei Province, in northern China in 2002 (n=30) and 2007 (n=20). The level of PCDD/Fs and dl-PCBs showed an increasing trend. The mean concentrations of PCDD/Fs plus dl-PCBs were 4.47 TEQ pg g(-1) fat and 6.24 TEQ pg g(-1) fat in human milk from Shijiazhuang in 2002 and in 2007, respectively. Based on statistical analysis of questionnaire data collected by in-person interviews with mothers, we found positive correlations between consumption of sea fish and PCDFs. The PCDDs, PCDFs, PCDD/Fs, and PCDD/Fs plus dl-PCBs levels in individuals consuming greater amounts of sea fish were higher than those consuming less sea fish, both with and without adjustments for potential confounding factors. Among 17 congeners of PCDD/Fs, the 2,3,7,8-TCDF, 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, 1,2,3,6,7,8-HxCDF, and 2,3,4,6,7,8-HxCDF congener concentrations in 2007 increased 134%, 55%, 53%, 57%, 65% and 130% when compared to 2002 levels, respectively. The 2007 dl-PCB congener levels were greater than those of the 2002 samples, with the exception of PCB81 and PCB77. Specifically, PCB105, PCB114, PCB118, PCB123 and PCB156 had increased greater than twofold from 2002 to 2007. Continuous surveillance of PCDD/F and dl-PCB levels in human milk is needed to accurately evaluate both environmental contamination and the human health risk to neonates in China.     

Bioethanol from sea lettuce with the use of crude enzymes derived from waste

The mid-gut gland of the scallop contains saccharification enzymes such as cellulase and amylase, and these enzymes have been disposed of together with the mid-gut gland after the removal of the adductor muscle, an edible part of the scallop. We used a drip from the mid-gut gland of the scallop, obtained by squeezing the gland, as an inexpensive enzyme mixture and tried to produce bioethanol from the glucans present in sea lettuce by the method of simultaneous saccharification and fermentation (SSF) with the use of baker’s yeast. The ethanol concentration attained was as high as 7.2 g/L, which corresponded to ~37% of the conversion of glucans in sea lettuce in the solid-state SSF. Furthermore, we ascertained that the drip and sea lettuce contain nutrients that are indispensable for maintaining the yeast activity, and, thus, the SSF did not require any additional nutrients, such as yeast extract or peptone, the use of which increases the cost of fermentation to a high level.     

Levels and regional trends of persistent organochlorines and polybrominated diphenyl ethers in Asian breast milk demonstrate POPs signatures unique to individual countries

Human breast milk samples collected in 2007–2008 from four countries, Vietnam (Hanoi), China (Beijing), Korea (Seoul) and Japan (Sendai, Kyoto and Takayama), were analyzed for persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane-related compounds (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Comparing with previous surveys, the present study indicates that the DDTs in breast milk from China and Vietnam had gradually decreased during the last decade, but were still 5–10 times higher than those in other nations. The ratios of p,p′-DDE/p,p′-DDT and o,p′-DDT/p,p′-DDT were higher in Beijing than in the other countries, suggesting that there is less fresh intake of commercial DDT products and a possible exposure to dicofol in China. CHL and PCB levels were relatively higher in mothers from Japan, whereas β-HCH and HCB were more common in Chinese women. In Japan, it is suspected that mothers in the urban/coastal area (Sendai) were more continuously exposed to organochlorine pesticides (OCPs) than mothers in the rural/inland area (Takayama). In addition, OCP levels in primiparae were significantly higher than those in multiparae from Japan and Korea. These indicate that both parity and regional factors are major determinants of the levels of OCPs and PCBs in human milk. On the other hand, higher concentrations of PBDEs were observed in mothers' milk from Korea. The congener was dominated by BDE-47 (43–54%), followed by BDE-153 (23–33%) in all regions except for Beijing where BDE-28 (23%) was relatively abundant. In Japanese breast milk, regional and parity-dependent distributions were not observed for PBDEs. Among PBDE congeners, age-dependency was observed for BDE-153, which was negatively correlated (p < 0.05) to the age of mothers in Kyoto (17 participants were housewives), while it increased with age in Sendai (10 participants were clerks). No such correlation was seen for BDE-47, indicating that BDE-47 was ingested and assimilated via different kinetics or routes from BDE-153 in Japan.     

Effect of tributyltin on veliger larvae of the Manila clam, Ruditapes philippinarum

We investigated the effects of waterborne and maternal exposure to tributyltin (TBT) on veliger larvae of the Manila clam, Ruditapes philippinarum. In a waterborne exposure test, veliger larvae (D-larvae stage: 24h after fertilization) were exposed to TBT at measured concentrations of <0.01 (control), 0.055, 0.130, 0.340, and 0.600microg/l for 13d. The percentage of normal veliger larvae (the ratio of normal veliger larvae to all larvae) decreased significantly in all TBT treatment groups compared with that in the control group. In a maternal exposure test, 100 clams were exposed to TBT at measured concentrations of <0.01 (control), 0.061, and 0.310microg/l at 20-22 degrees C for 3 weeks, and the percentage of normal veliger larvae assessed for 13d. No maternal effects on veliger larvae from TBT were observed in TBT treatment groups as compared with the control group. These results demonstrate that waterborne TBT affects Manila clam veliger larvae, and indicates that TBT may have reduced Manila clam populations by preventing the development and survival of veliger larvae.     

Concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls in blood collected from 195 pregnant women in Sapporo City, Japan

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho coplanar polychlorinated biphenyls (non-ortho PCBs), and mono-ortho coplanar polychlorinated biphenyls (mono-ortho PCBs) in blood collected between 2002 and 2004 from 195 pregnant women living in Sapporo City of Hokkaido Prefecture, Japan. The present study is one of the few studies in which PCDDs, PCDFs, and dioxin-like PCBs have been measured in the blood of pregnant women. Of the 195 pregnant women, 101 were primipara (mean: 28.8 years) and 94 were multipara (mean: 32.4 years). The arithmetic mean total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs of primiparous and multiparous mothers in Sapporo City were 17.4 (median: 15.7) and 14.0 (median: 13.9)pgTEQ/glipid, respectively, and the concentrations were in the range of 6.6-43.4 and 3.4-28.2pgTEQ/glipid, respectively. In regard to the relationship between the total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in maternal blood and the number of deliveries or age of primiparous and multiparius mothers, the levels of these dioxin-like compounds tended to decrease with increases in the number of deliveries and significantly increased with increasing maternal age in both groups. Furthermore, significant correlations were observed between the total TEQ concentrations of these dioxin-like compounds and the age of primiparae and multiparae. The total TEQ concentration of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs measured in 195 pregnant women has decreased compared to past levels in Japan for the last several decades. The results of the present study have indicated that dioxin contamination in the blood of young women in Japan is continuing to decrease.     

Immunologic effects of perinatal exposure to dioxins, PCBs and organochlorine pesticides in Japanese infants

Effects of perinatal exposure to dioxins, PCBs and organochlorine pesticides on lymphocyte subsets were investigated in the peripheral blood from 101 Japanese infants with approximately 10 months of age. Perinatal exposure to these organochlorine compounds were estimated by their contamination levels in the breast milk of the mothers. Lymphocyte subsets such as CD16+, HLA-DR+, CD4+, CD4+8+, CD8+, CD3+ and CD20+ cells in peripheral venous blood were assessed in a subgroup of 92 infants. Greater exposures to HCE, chlordane and dioxins were significantly associated with the increase in the percentages of CD8+ and CD3+ T lymphocytes and CD4+/CD8+ T cell ratios, respectively. In addition, higher HCH exposure was also associated with a decrease in the percentage of HLA-DR+ T lymphocytes. Furthermore effects of dioxins, DDT and PCBs on the percentage of CD16+ T lymphocyte were more pronounced by the combined exposure of dioxins and PCBs or by the combined exposure of DDT and PCBs. Effects of HCE on the percentages of CD8+ T lymphocyte were also more pronounced by the combined exposure of HCE and chlordane. In conclusion, our study suggests that greater exposures to dioxins, PCBs and organochlorine pesticides determined in this study (except dieldrin) influence the immune system of Japanese infant, although the clinical significance of these changes is uncertain.