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类脂分子标志物在海洋有机地球化学中的研究应用 总被引:1,自引:2,他引:1
分子标志物是海洋有机地球化学过程研究的一个重要手段,它的开发和应用使得海洋有机地球化学的过程研究成为可能。类脂化合物作为一类最常用的分子标志物,在物质来源、有机质降解、早期 成岩演变、环境污染、古海洋学等诸多方面有着广泛的应用。类脂分子标志物成功地应用在河口、滨海地区和深海海洋中有着物质循环、迁移和埋藏等过程的研究,为海洋有机地球化学过程提供定性或定量的描述。本文简要介绍了类脂分子标志物的特征、开发和利用,并讨论了其优、缺点。 相似文献
185.
碘是人体必需的微量元素之一,高碘或低碘均能引起人类或动物的各种疾病。对天津东部地区水土环境中碘地球化学特征及成因进行了研究,结果表明,研究区表层土壤碘含量变化范围是0.89~17.09 mg/kg,平均为5.11 mg/kg,是天津市背景值的1.92倍,是全国背景值的1.36倍。深层土壤碘含量在0.64~34.55 mg/kg之间,平均为10.73 mg/kg,是天津市深层土壤基准值的3.93倍,是研究区表层土壤的2.1倍,研究区表层和深层土壤碘均处于富集状态。表层土壤碘高背景区分布面积较大,主要集中分布在东丽区、宁河区南部、滨海新区北部。浅层地下水碘含量范围在0.03~4.00 mg/L之间,平均为0.56mg/L,高碘地下水分布面积较大,主要分布在东丽区、津南区、宁河区南部、滨海新区(除去西南部)。研究区历史上海陆交互作用强烈,海水提供的大量碘物质在此残留富集,可能是造成水土环境中碘元素整体偏高的自然原因。 相似文献
186.
珠三角新会地区表层土壤硒、氟、碘地球化学特征研究 总被引:1,自引:0,他引:1
以珠江三角洲新会地区西江、潭江下游的三江、睦州、古井三镇土壤为主要研究对象,测试分析所采集的1 567件表层土壤样品全氮(N)、有机碳(Org.C)、pH等理化指标和二氧化硅(SiO_2)、三氧化二铝(Al_2O_3)、硒(Se)、氟(F)、碘(I) 5种元素组分含量,以及60件稻谷样的硒(Se)含量。重点探讨了研究区Se、F、I的含量、分布及其影响因素等地球化学特征。结果表明,研究区土壤呈现强酸性-酸性,Se、F、I的含量均值分别为0. 50 mg/kg、617. 39 mg/kg、3. 57 mg/kg,Se、F高于全国土壤背景值,I低于全国土壤背景值; Se、F、I均与Al_2O_3、Org.C以及pH相关,F与Se不相关,F与I负相关。Se、F、I的含量、分布等地球化学特征受地层控制:不同成土母质中,基岩区和花岗岩区Se、I含量较高;第四纪沉积区F含量较高。推测Se和I主要源于燕山期的火山活动,F主要源于三角洲的沉积作用。总体上研究区土壤呈现足硒、富硒,碘适量,氟过剩的特征,稻谷富硒率也高,具备开发天然富硒农产品的条件。 相似文献
187.
湖泊沉积物重金属污染研究 总被引:1,自引:0,他引:1
湖泊的生态环境状况与人类生存环境和社会经济发展有着密切的关系。本文主要通过介绍东湖和太湖湖泊沉积物重金属污染阐释我国现在湖泊底泥重金属污染状况。 相似文献
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Lead (Pb) is a toxin that after childhood exposure poses a lifetime of health risks. One route of exposure is soil-Pb as a
result of ∼12 million metric tons of Pb residue in paint and gasoline sold in the US during the 20th Century. Pb accumulated
in soil of the community is a good predictor for blood Pb of children living there. This retrospective study compares the
soil-Pb on Housing Authority of New Orleans (HANO) properties with adjacent private residential (RES) properties within a
0.8 km (0.5 mile) radius. The sample subset (n = 951) is from two soil-Pb surveys (total n = 9,493) conducted between 1989 and 2000. The properties were in both the inner city (CORE) and outlying (OUTER) communities.
The data were analyzed using multi-response permutation procedures (MRPP). The soil-Pb results differ significantly (P-value < 0.001) on same-aged HANO properties at different locations; thus, year of construction does not give adequate explanation
for the soil-Pb differences. HANO and RES soils are significantly more Pb contaminated in the CORE than in OUTER communities
(P-value < 0.001). The CORE has many more years of traffic congestion than OUTER communities; therefore, the lead additives
to gasoline, and not lead-based paint, best elucidate the differences of the soil-Pb footprint at HANO and RES properties
in the CORE and OUTER communites. Currently HANO properties are being redeveloped with cleaner soil, but soil on RES properties
in the CORE of New Orleans remains a large source of Pb (median = 707 mg/kg in this study) for human exposure, especially
children. 相似文献
190.
Abboud IA 《Environmental geochemistry and health》2008,30(1):11-20
Due to the increase in the number of urinary calculi disease cases in Jordan, stone samples were collected from patients from
various Jordanian hospitals (Princes Basma (PBH), King Abdullah University (KAUH), Al-Basheer (ABH) and Al-Mafraq (AMH)).
This study concentrates on the effect of trace metals in patients of urinary calculi. Trace metals were detected in 110 urinary
calculi samples using X-ray fluorescence (XRF) and atomic absorption spectroscopy (AAS) techniques. Of the calculi examined,
21 were pure calcium oxalate (CaOax), 29 were mixed calcium oxalate/uric acid, 23 were mixed calcium oxalate/phosphate (apatite),
25 were phosphate calculi (apatite/struvite), five were mixed calcium oxalate monohydrate/struvite, four were urate calculi
(mixed ammonium acid urate/sodium acid urate) and three were pure cystine calculi. The concentration measurement of Ca and
other trace metals levels has been found useful in understanding the mechanism of stone formation and in evaluating pathological
factors. It has been found that Ca is the main constituent of the urinary calculi, especially those stones composed of calcium
oxalate and calcium phosphate. The concentration of most of the trace metals that were analyzed was (Ca = 48.18, Na = 1.56,
K = 0.9, Mg = 3.08, Fe = 1.17, Al = 0.49, Zn = 0.7, Cu = 0.19, Mn = 0.029, P = 10.35, S = 1.88, Sr = 0.306, Mo = 0.2, Cr = 0.146,
Co = 0.05, Ni = 0.014)%. In conclusion, metals concentration in Jordanian patient’s urinary calculi samples was higher than
its equivalents of other patients’. It has been noted that there is no concentration of toxic trace elements (like Li, V,
Pb, Cd, and As). Some heavy metals, however, were detected Mo, Cr, Co and Ni as traces. P and S ions are present in few calculi
stones as traces. 相似文献