Heavy metal pollution in vegetables grown in the vicinity of a multi-metal mining area in Gejiu,China: total concentrations,speciation analysis,and health risk

A field survey was conducted to investigate the present situation and health risk of arsenic (As), lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) in soils and vegetables in a multi-metal mining area, Gejiu, China. Furthermore, three vegetables (water spinach, potato, and summer squash) containing high metal concentrations were selected to further analyze metal speciation. The results showed that the average concentrations of five metals in soil exceeded the limiting values, and their bioavailable concentrations were significantly positively correlated to the total ones. Heavy metals in the edible parts of vegetables also exceeded the corresponding standards. The leaves of pakchoi, peppermint, and coriander had a strong metal-accumulative ability and they were not suitable for planting. Except the residue forms, the main forms of metals in the edible parts of three selected vegetables were ethanol-, NaCl-, and HAc-extractable fractions for As, Pb, and Cd, respectively; however, Cu was mainly presented as NaCl-extractable and Zn as HAc-extractable fractions. A high proportion of ethanol-extractable As showed that As bioactivity and toxic effects were the highest. Although the total and bioavailable Cd were high in soil, its speciation in vegetables was mainly presented as HAc-extractable fraction, which has a relatively low bioactivity. Lead and arsenic were imposing a serious threat on the local residents via vegetable consumption.     

Risk for estrogen-dependent diseases in relation to phthalate exposure and polymorphisms of CYP17A1 and estrogen receptor genes

Evidence has shown that polymorphisms of various genes known to be involved in estrogen biosynthesis and function are associated with estrogen-dependent diseases (EDDs). These genes include CYP17A1, estrogen receptor 1 (ESR1), and 2 (ESR2). Phthalates are considered estrogenic endocrine disruptors, and recent research has suggested that they may act as a risk factor for EDDs. However, extremely few studies have assessed the effects of gene–environment interaction on these diseases. We recruited 44 patients with endometriosis or adenomyosis, 36 patients with leiomyoma, and 69 healthy controls from a medical center in Taiwan between 2005 and 2007. Urine samples were collected and analyzed for seven phthalate metabolites using liquid chromatography tandem mass spectrometry. Peripheral lymphocytes were used for DNA extraction to determine the genotype of CYP17A1, ESR1, and ESR2. Compared to controls, patients with leiomyoma had significantly higher levels of total urinary mono-ethylhexyl phthalate (ΣMEHP) (52.1 vs. 29.6 μg/g creatinine, p?=?0.040), mono-n-butyl phthalate (MnBP) (75.4 vs. 51.3 μg/g creatinine, p?=?0.019), and monoethyl phthalate (MEP) (103.7 vs. 59.3 μg/g creatinine, p?=?0.031). In contrast, patients with endometriosis or adenomyosis showed a marginally increased level of urinary MEHP only. Subjects who were homozygous for both the ESR1 C allele (rs2234693) and CYP17A1 C allele (rs743572) showed a significantly increased risk for leiomyoma (OR?=?19.8; 95 % CI, 1.70; 231.5; p?=?0.017) relative to subjects with other genotypes of ESR1 and CYP17A1. These results were obtained after adjusting for age, cigarette smoking, MEHP level, GSTM1 genotype and other covariates. Our results suggested that both CYP17A1 and ESR1 polymorphisms may modulate the effects of phthalate exposure on the development of leiomyoma.     

活性污泥缺氧转化1-2-7-三氨基-8-羟基-3-6-萘二磺酸

1—2-7-三氨基-8-羟基-3—6-萘二磺酸（TAHNDS）作为偶氮染料的脱色产物很难被常规的厌氧-好氧染料废水处理工艺所去除。研究了未经驯化的活性污泥对TAHNDS的缺氧转化效果。结果表明,只有在特定的缺氧条件下（ORP在-50～-150mV之间）,TAHNDS才能被活性污泥所降解转化。当浓度在10—80mg／L范围内,TAHNDS可在72h内转化93％以上。加入100mg／L的硝酸盐和0．64mmol／L的氧化还原介体蒽醌-2-磺酸钠（AQS）可将40mg／L的TAHNDS的转化时间从84h缩短到36h。光谱及HPLC—MS分析表明,TAHNDS在缺氧条件下主要是通过脱氨基和脱磺酸作用生成已知可好氧生物降解的3,5-二氨基4-羟基萘-2-磺酸。因此,缺氧处理有望作为预处理工艺促进废水中TAHNDS的完全降解。     

一株抗Cd~（2＋）菌株的筛选及其吸附性能

Cd2＋为一种毒性金属元素,为了实际解决污水中低浓度重金属污染,实现污水达标排放,通过12C6＋重离子束辐照诱变技术筛选到一株耐受Cd2＋的菌株C2,研究其对Cd2＋的抗性和低浓度Cd2＋的吸附性能表明,Cd2＋浓度≤100 mg/L时,C2菌株可以生长繁殖,但随Cd2＋浓度升高受到抑制;SEM分析表明,受到Cd2＋胁迫时,C2产生大量胞外产物与Cd2＋形成络合物;吸附过程中菌粉表面空隙得到填充,形成凸起;红外光谱分析表明,吸附过程中的主要作用基团为醇羟基O—H键、氨基和酰胺基团;C2菌粉和固定化菌球都对Cd2＋有较好的吸附能力,菌粉吸附效果比固定化菌球稍好;菌粉和固定化吸附剂的最佳吸附初始pH值为5~6.0,最佳投加量分别为1.0 g/L和10 g/L（实际含菌量为1.0 g/L）;Cd2＋浓度在2~20mg/L时,在最佳吸附条件下,菌粉和固定化吸附剂对Cd2＋的吸附率均在90%左右;2种吸附剂吸附过程与Langmuir等温模型和拟二级动力学模型拟合最佳;热力学研究表明吸附反应均能自发进行。以上研究结果表明,C2菌粉和固定化吸附剂均可用于污水中低浓度Cd2＋的去除。     

3种运行模式下CAST工艺脱氮性能

以模拟城市污水为处理对象,采用循环式活性污泥法（CAST）反应器,对3种运行模式（M1：常规模式,M2：缺氧好氧模式、M3：缺氧好氧交替模式）下系统的脱氮性能进行了研究,比较了各模式下CAST反应器的氨氮和总氮的去除效率,并对各模式下典型周期内氮基质浓度变化进行了考察,以确定系统的脱氮模式。结果表明,在氨氮去除不成为限制条件（去除率〉90％）的条件下,3种运行模式下系统总氮的平均去除率分别为67．3％、70．6％和82．4％,以缺氧好氧交替模式下的最高;M1、M2和M3均可实现亚硝酸型硝化,但随着温度的升高,亚硝酸型硝化逐渐消失。静态实验分析表明,3种模式下系统的氨氧化速率大小次序为：vN：M1〉vN：M2〉vN：M3,反硝化速率大小次序为：vDN,M2〉vDN,M3〉vDN,M1。     

Ce-PbO_2/C电极的制备及其去除水中酸性红B

采用电沉积法制备铈修饰的PbO2/C电极,通过SEM、XRD、XPS及循环伏安对PbO2/C、Ce-PbO2/C电极进行表征,结果表明,Ce-PbO2/C电极比PbO2/C颗粒细小,表面均匀致密,电化学氧化能力较强,修饰电极中Ce以CeO2的形态存在。以Ce-PbO2/C为工作电极,电解浓度为1 000 mg/L的高盐酸性红B模拟活性染料废水,考察了电压、pH、电解质浓度、极间距对脱色率、氨氮去除率及COD去除率的影响。确定适宜工艺条件为：初始酸性红B溶液浓度为1 000 mg/L,pH值为6,电压10 V,电解时间1 h,电极间距1.5 cm,该条件下脱色率、氨氮去除率和COD去除率分别为99.98%、97.23%和90.17%。通过UV-Vis及GC-MS初步分析了降解过程可能存在的中间产物及降解途径。     

臭氧氧化6-APA制药厂生化处理出水的特性及动力学简

通过现场实验研究了6-APA制药厂生化处理出水的臭氧氧化特性及其动力学规律。结果表明,当臭氧浓度为27.5 mg/L,气水接触时间为80 min时,COD、UV₂₅₄、NH₃-N和色度的去除率分别可达72.95%、73.28%、72%和96.25%,达到《发酵类制药废水工业水污染物排放标准》（GB 21903-2008）排放控制要求。拟合结果表明,在0~10、10~30和30~90 min时段内,臭氧氧化过程遵循拟一级反应,但反应速率逐渐降低。当气水接触时间为30 min时,废水可生化性可由0.1提高至0.35,采用臭氧/生物处理的联合工艺也有望使出水达到相同的排放控制要求。     

MCM-41介孔分子筛的合成及其对铜离子的吸附性能简

以微硅粉为硅源,CTAB和PEG-6000为模板剂,合成MCM-41介孔分子筛。采用XRD、N₂吸附-脱附曲线、FTIR以及TEM表征了其结构、比表面积、孔径分布及晶体形貌,并且以该样品为吸附剂,对含Cu²⁺的溶液进行了静态吸附实验。结果表明,以微硅粉为硅源成功合成了具有典型六方排列孔道结构的MCM-41,其比表面积为869.5 m²/g,孔容为0.97 cm³/g,平均孔径为3.3 nm;溶液pH为5~6时,MCM-41对Cu²⁺的去除效果最好;MCM-41对Cu²⁺的最大吸附吸附容量36.3 mg/g;MCM-41对Cu²⁺的吸附性能符合Langmuir吸附方程的特征。动力学研究表明,该过程符合准二级动力学模型。     

混凝-超滤短流程工艺处理北方水库原水简

采用混凝-超滤膜短流程工艺对大伙房水库原水进行处理,考察其除污染性能和膜污染情况,并对该短流程工艺参数进行优化。结果表明,当利用超滤膜直接过滤原水时,膜污染较重,并且对污染物质的去除率较低;而采用混凝-超滤短流程工艺时,膜污染得到一定程度上的缓解;当絮凝剂投加量为7 mg/L、膜清洗周期为30 min时,对浊度、COD_Mn和UV₂₅₄的去除率分别为95.61%、40.42%和37.12%,出水水质能够满足生活饮用水卫生标准。     

臭氧氧化法处理焦化废水生化出水的反应动力学简

对臭氧氧化去除焦化废水生化出水COD的反应动力学及其影响因素进行了实验研究,结果表明,在臭氧投加量为8.50 mg/min,反应温度为20℃和初始pH为10.61条件下,对COD的降解符合表观一级反应动力学模型,其相关系数R²=0.9991,表观反应速率常数k_Abs=1.01×10^-3 s^-1。该条件下,臭氧氧化对COD的降解主要来源于高活性羟基自由基的强氧化作用。在不同的臭氧投加量（4.25~12.75 mg/min）、不同的反应温度（10~40℃）和不同的初始pH（3.76~12.53）下,COD的降解也同样遵循一级反应动力学规律。随着臭氧投加量的增大,COD降解的表观反应速率常数从（0.554×10^-3） s^-1增加到（1.06×10^-3） s^-1;随着反应温度的升高,表观反应速率常数从（0.427×10^-3） s^-1增加到（1.40×10^-3） s^-1,温度越高反应速率提高的幅度却越小;在初始pH3.76~10.61范围内,表观反应速率常数从（0.218×10^-3） s^-1增加到（1.01×10^-3） s^-1,在初始pH为12.53时表观反应速率常数下降到（0.857×10^-3） s^-1。