超声波萃取—高效液相色谱法测定环境空气总悬浮颗粒物中的苯并(a)

对大气总悬浮颗粒物中的苯并（ａ）芘进行了超声波清洗机萃取—高效液相色谱法分析测定．研究了样品的处理方法，考察了萃取过程中，萃取剂类型、萃取剂用量、萃取时间等因素对测定结果的影响，确立了最佳萃取条件．此方法简便快速，灵敏度高，分析结果令人满意     

应用~(32)P示踪技术研究不同土壤慢速土地处理系统内磷素的行为规律

应用放射性32 P示踪技术 ,在人工模拟土柱装置上 ,对城市污水中的磷素在不同土壤内的行为规律进行研究 ,并对实验数据进行了归一化的计算处理 ,结果表明红壤和紫色土对城市污水中的磷素都有较强的去除能力 ,但磷素在不同土壤中的行为有明显差异。     

黄孢原毛平革菌P450对难降解有机物降解的研究现状

难降解有机物由于具有极大的环境危害,已成为环境保护的一大难题.其降解的主要研究方向是依靠微生物的降解功能.黄孢原毛平革菌(P.C.菌)是研究异源物质代谢最广泛的白腐真菌.目前的研究主要集中在胞外木质过氧化物酶和锰过氧化物酶,而对胞内细胞色素P450降解功能的研究还很少.     

Climate controls on dust storm occurrence in Maowusu Desert, Inner Mongolia, north China

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Testing the Norwegian phosphorus index at the field and subcatchment scale

Simple risk assessment tools for agricultural phosphorus (P) losses, like the P index, have been developed in the U.S.A. and in some European countries. Despite its popularity, there have been surprisingly few studies, which try to test the index close to the field scale. For Norway, the P index approach comprises the risk related to both the source of P (soil P status, amount of fertilizer and manure as well as method of application, plant P release by freezing and P balance) and the risk related to transport of P (erosion, flooding, surface runoff, contributing distance, modified connectivity, soil profile, subsurface drainage). In this paper, we have applied the Norwegian P index to farmer fields within a small agricultural catchment, the Skuterud catchment (450 ha), in southeastern Norway. The Norwegian P index was tested for two agricultural fields (0.3–0.4 ha) and nine subcatchments (6–65 ha). Total P concentrations in runoff from the 11 study areas were measured during the year from May 2001 to April 2002. Results from the testing showed that the Norwegian P index described 66% of the variation in measured relative total P concentration for fields and subcatchments included in this study. Additionally, the P index was able to detect fields and subcatchments with the highest measured P concentrations. Results also showed that the source factor contributed most to the variation between fields and hence were important for the identification of high-risk areas in Skuterud catchment. It was found that the soil P status described 66% of the variation in the source factor. Among the transport variables, it was found that both erosion risk and contributing distance had an important influence on the transport factor. Overall, the study illustrated the potential of the P index to detect areas with the highest risk of P loss.     

人工合成P型沸石对NH4^＋交换特性研究

应用由粉煤灰合成的P型沸石研究对NH_4~ 交换的热力学和动力学特性。结果表明,P型沸石阳离子交换总量为264meq/100g,在其整个阳离子组成范围内对进入的NH_4~ 具有高的选择交换性,该交换过程能自发沿着正方向进行,随着温度的增高,其交换能力也增强。Na~ =NH_4~ 交换过程具有较优越的动力学特性,在16℃和32℃时,P型沸石中NH_4~ 自扩散系数分别为7.14×10~(-10)和1.12×10~(-9)cm~2·s~(-1);活化能为20.74kJ·mol~(-1);活化熵分别为-88.26和-88.71J·(mol·°K)~(-1);自由能分别为43.85和45.26kJ·mol~(-1)。     

某污水灌区居民胃癌高发的病因研究

某污水灌区居民恶性肿瘤死亡回顾调查发现,胃癌标化死亡率重污染地区明显高于一般污染区及对照区,是全国农村胃癌标化死亡率的3倍.通过污灌区居民临床体检和肠型胃癌的肠上皮抗原——α_2GP 对血清免疫学检测,发现胃癌高发与本地人群慢性萎缩性胃炎的粘膜肠上皮化生有密切联系,环境卫生与环境流行病学调查进一步证明污灌地区居民的胃粘膜肠上皮化生又和灌区污染的井水及稻米中某些矿物油、苯并(a)芘等污染物长期刺激有关,经试验均具有效突变活性.据此,作者初步提示了某污灌区居民胃癌的发生模型.     

根生沉水植物菹草(Potamogeton crispus)对滇池水体的净化作用

研究了根生沉水植物菹草对富营养和重金属等污染的滇池水体和底泥的净化作用。结果表明,菹草对水体和底泥中的P、N、Pb、Zn、Cu、As有较大的吸收、富集量,单位生物量的菹草对N、Cu的富集量>水葫芦>茭草>芦苇,P、Zn则>茭草>芦苇;对底泥中N、P、Cu、Pb的吸收系数>水葫芦,尤以N、P为最显;研究还表明,植物对水体和底泥中污染物的富集量和净化效率与生物量大小有关,当菹草保持其群体覆盖率为50%时,生物量最大,净化效率也最大。     

Sequential fractionation of reactive phosphorus in the sediment of a shallow eutrophic lake——Donghu Lake, China

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Chemical and spectral characterization of soil phosphorus under three land uses from an Andic Palehumult in West Cameroon

Phosphorus (P) is one of the main limiting plant nutrients in most tropical soils. Acquiring quantitative information on soil P status is essential for evaluating its sustainable management in agroecosystems. The objective of this study was to evaluate how land-use shifts from semi-permanent food crop systems (CF) to plantations of tea (Camellia sinensis) (TP) and Eucalyptus grandis (EP) impact on both organic and inorganic P species. Determination of phosphorus status combined a P sequential fractionation procedure and ³¹P nuclear magnetic resonance (NMR) spectroscopy. Sequentially extracted pools included available P by 0.5 M NaHCO₃, Al/Fe-P by 0.1 M NaOH, Ca-P by 0.5 M HCl and residual P by 0.5 M H₂SO₄ after ignition at 550 °C. Soil total P (STP) varied significantly across land uses (P<0.05) with the lowest mean value (1025.6±23.1 mg kg⁻¹) occurring under CF and the highest (1698.0±86.1 mg kg⁻¹) under TP. The largest P-pools were NaOH-P (47–51% of total soil P) and H₂SO₄-P (25–32%). NaHCO₃-P_i under fertilized land uses (CF and TP) was greater than 12 mg kg⁻¹ indicating that these systems were sustainable. Unfertilized EP was P-deficient, probably as the result of organic-matter accretion and subsequent P immobilization in organic forms. ³¹P NMR revealed that 88–89% of P compounds in NaOH extract were organic with monoester-P accounting for 59.1–60.8%. This was followed by diester-P (9.8–12.4%), teochoic acid (8.4–10.1%), orthophosphate (8.8–9.7%), unknown compounds (7.4–8.4%), pyrophosphate (1.1–4.6%) and phosphonate (0–1.3%). EP had higher diester-P and no phosphonate compound whereas CF had substantial amount of pyrophosphate (4.6%) and less orthophosphate and teochoic acid. These results indicate that these last P compounds are easily mineralizable P forms participating actively in plant P nutrition.