植物对甲醛吸收的气相色谱研究

为了比较几种常见居室观赏性植物对室内甲醛的吸收效果,本文采用定时抽取放有植物的密闭箱内气体,以蒸馏水吸收,直接进样气相色谱法测定甲醛浓度．结果显示甲醛的浓度在0．2～1．0μg／mL范围内,线性关系良好,回归方程Y=0．14261x-0．14711,（r=0．99657,n=6）,检测限为0．053μg／mL;样品分析的精密度试验,相对标准偏差为1．27％．可见,以蒸馏水直接进样气相色谱的方法测定植物对甲醛吸收准确、简便．植物对甲醛吸收能力为：芦荟〉虎尾兰〉仙人掌〉玉树．     

Exposure to Formaldehyde in Indoor Air

Trends in formaldehyde concentrations to which residents are exposed are reviewed, as are the means for assessing these exposures. Concentrations as high as a few ppm encountered in manufactured housing during the 1970s were eliminated after the Housing and Urban Development (HUD) 1984 ruling came into effect. The pressed-wood product industry, and its trade organizations, have made concerted efforts to comply with the ruling. Moreover, they have imposed additional voluntary product standards upon themselves intended to be applicable to a range of pressed-wood products wider than that defined in the HUD standard. Quarterly product testing on arbitrarily selected products shows a general lowering of emission rates with only a few percent of products now being above the HUD level. Measurement of ambient indoor levels of formaldehyde has been largely replaced by testing to assure conformance to product standards. The loweremitting products on the market, if used in mobile home construction and furnishing, will expectantly produce formaldehyde levels not exceeding 0.1 ppm, except under conditions of unusually high temperature and humidity. Recent studies implicate household dust as a significant carrier of bound formaldehyde. In a few instances, old urea-formaldehyde cavity wall insulation has become friable and particles have blown into living areas. Future health assessments might need to consider this additional pathway of potential exposure.     

Quantitative Cancer Risk Estimation for Formaldehyde

Of primary concern are irreversible effects, such as cancer induction, that formaldehyde exposure could have on human health. Dose-response data from human exposure situations would provide the most solid foundation for risk assessment, avoiding problematic extrapolations from the health effects seen in nonhuman species. However, epidemiologic studies of human formaldehyde exposure have provided little definitive information regarding dose-response. Reliance must consequently be placed on laboratory animal evidence. An impressive array of data points to significantly nonlinear relationships between rodent tumor incidence and administered dose, and between target tissue dose and administered dose (the latter for both rodents and Rhesus monkeys) following exposure to formaldehyde by inhalation. Disproportionately less formaldehyde binds covalently to the DNA of nasal respiratory epithelium at low than at high airborne concentrations. Use of this internal measure of delivered dose in analyses of rodent bioassay nasal tumor response yields multistage model estimates of low-dose risk, both point and upper bound, that are lower than equivalent estimates based upon airborne formaldehyde concentration. In addition, risk estimates obtained for Rhesus monkeys appear at least 10-fold lower than corresponding estimates for identically exposed Fischer-344 rats.     

VA菌根培养土的化学灭菌法研究

无菌土是得到 VA 菌根真菌纯培养的基础,本试验用化学药剂代替高压蒸汽进行土壤灭菌,结果表明,用土壤重量0.1%的甲醛处理土壤,达到了高压蒸汽灭菌的相同效果,并具有成本低、收益大、易操作等特点。这是目前用于农业生产的一种有效的、可行的、新的土壤灭菌方法,为 VA 菌根真菌在农业上的应用开辟了良好的前景。