Dietary exposure to di-isobutyl phthalate increases urinary 5-methyl-2′-deoxycytidine level and affects reproductive function in adult male mice

Phthalates are a large family of ubiquitous environmental pollutants suspected of being endocrine disruptors. Epidemiological studies have associated phthalate metabolites with decreased reproductive parameters and linked phthalate exposure with the level of urinary 5-methyl-2′-deoxycytidine(5mdC, a product of methylated DNA). In this study, adult male mice were exposed to 450 mg di-isobutyl phthalate(DiBP)/(kg·day) via dietary exposure for 28 days. Mono-isobutyl phthalate(Mi BP, the urinary metabolite) and reproductive function parameters were determined. The levels of 5mdC and 5-hydroxymethyl-2′-deoxycytidine(5hmdC) were measured in urine to evaluate if their contents were also altered by DiBP exposure in this animal model. Results showed that DiBP exposure led to a significant increase in the urinary 5mdC level and significant decreases in sperm concentration and motility in the epididymis, accompanied with reduced testosterone levels and downregulation of the P450 cholesterol side-chain cleavage enzyme(P450scc) gene in the mice testes. Our findings indicated that exposure to DiBP increased the urinary 5mdC levels,which supported our recent epidemiological study about the associations of urinary 5mdC with phthalate exposure in the male human population. In addition, DiBP exposure impaired male reproductive function, possibly by disturbing testosterone levels; P450scc might be a major steroidogenic enzyme targeted by DiBP or other phthalates.     

进出水方式对高负荷浅层渗滤净化生活污水效果的影响

为研究农村分散住户用水不均匀和排放泵井运行不连续条件下高负荷地下浅层渗滤系统的净化效果,建立渗滤试验柱,以实际生活污水为进水,在12.5 cm.d-1日均水力负荷下,比较连续进水、间歇进水和自由排水、间歇排水对实际生活污水净化效果的影响。结果表明,各渗滤柱对NH4+-N的平均去除率均大于96%。对COD的平均去除率为41.2%～67.7%,其中采用间歇进水、间歇排水方式的渗滤柱去除率最低,但出水仍可达到GB8978—1996《污水综合排放标准》中二级标准。各渗滤柱对TN的平均去除率为17.5%～37.2%,其中采用间歇进水、间歇排水的渗滤柱平均去除率最高,表明强化反硝化作用是提高脱氮效率的主要途径。对TP的平均去除率为51.0%～78.0%,其中采用连续进水、间歇排水的渗滤柱平均去除率最高,表明延长污水停留时间、增加与填料的接触面积能增强对TP的去除效果。间歇进水、间歇排水方式下,渗滤柱对COD的去除效果有所下降,但是对N、P营养盐的综合去除效果最好。     

Removal of PAHs with surfactant-enhanced soil washing: influencing factors and removal effectiveness

PAH removal with surfactant enhanced washing was investigated through a series of laboratory tests to examine the effect of stirring speed, washing time, surfactant concentration, liquid/solid ratio, temperature, and on-and-off mode. The first four factors show significant influence on the PAH removal while the latter two do not. Total removal ratio and a new proposed parameter, solubilization percentage, are used to evaluate the effectiveness quantitatively.     

Distribution of alkylphenols in the Pearl River Delta and adjacent northern South China Sea, China

The occurrence of alkylphenols (APs) was investigated in surface water and sediments from the Pearl River Delta and adjacent northern South China Sea. Most of the water samples contained detectable amounts of APs, ranging up to 0.628 microg l(-1) for nonylphenol (NP) and 0.068 microg l(-1) for octylphenol (OP). APs were found in all of the sediment samples with concentrations ranging from 59 to 7808 microg kg(-1) for NP and from 1 to 93 microg kg(-1) for OP. The Zhujiang River showed the highest concentrations of APs in both water and sediments. Significant decrease of APs concentrations going from the Zhujiang River to the Shiziyang River was observed. The Xijiang River contained concentrations of APs slightly higher in water but relatively lower in sediments than the Lingding Bay, which might be attributed to their different hydrodynamic and sedimentary characteristics. There was a decreasing trend of APs in water from the rivers to the estuary and further to the sea on the whole. In the Lingding Bay and its outer waters, concentrations of APs in sediments increased to a maximum and then decrease seaward, which was consistent with the distribution trend of the sediment organic carbon contents. Linear regression analyses showed the concentrations of APs were markedly correlated with the sediment organic carbon contents, indicating that the sediment organic carbon is an important factor controlling the levels of APs in sediments.     

三峡水库135 m蓄水前后水体重金属环境健康风险评价

三峡水库135 m蓄水后,水体中各重金属的单因子污染指数和Nemerow综合污染指数均有不同程度的增大,特别是Pb污染应该引起重视.健康风险评价结果表明,成库前后非致癌有毒化学物质(Hg、Pb和Cu)所引起的健康危害的个人年风险为Pb＞Cu＞Hg,致癌物质对人体健康危害的个人年风险均大于非致癌物.各类污染物所致个人平均健康危害成库前后均低于国际辐射防护委员会(ICRP)推荐的标准,为可接受水平.     

预曝-混凝沉淀-微絮凝过滤工艺处理钢帘线污水

采用预曝-混凝沉淀-微絮凝过滤工艺处理子午轮胎钢帘线厂废水,并循环回用.经过3年运行结果表明,出水水质符合<污水再生利用设计规范>(GB50335-2002)中循环冷却水水质控制指标,并达到车间生产用水要求.该工艺运行稳定,管理方便,完全实现零排放.     

公路隧道通风控制系统的研究

通风系统是长大公路隧道的重要组成部分.将隧道内有害气体及粉尘浓度控制在容许限度之内,是通风控制的目的.通过传感器采集隧道内有害气体及粉尘浓度,并将主要的控制参数传递给上位机,一旦超标就启动声光报警和风机换气.考虑到节能的同题,将变频调速技术应用到隧道通风控制中.     

气溶胶中正构烷烃单体化合物稳定碳同位素分布特征初步研究

不同来源的气溶胶中正构烷烃稳定碳同位素的分布特征有比较明显的区别,以低陆生植物为主的高原清洁区,其气溶胶中正构烷烃δ＾１３Ｃ较轻,随碳数的增加,δ＾１３Ｃ较平平缓的曲线,以高等植物为主的海滨清洁区,正构烷烃δ＾１３Ｃ分布亦为较平缓的英线,但δ＾１３Ｃ较前者稍重,为－２８‰－－２７‰;人为污染严重的城市区,气溶胶正构烷烃δ＾１３Ｃ为－２９‰－－２５‰,且随碳数的增加有较大的变化。     

ABR发酵系统运行特性及产氢效能研究

为解决连续流搅拌槽式反应器(CSTR)发酵制氢系统存在的不足,如单位基质氢气转化率低、因搅拌带来的耗能,抗负荷冲击能力不强等问题,开展了厌氧折流板反应器(ABR)发酵产氢的研究.结果表明,在35℃和进水COD 5000mg/L等条件下,ABR系统可在26d达到乙醇型发酵,其比产氢速率为0.13L/(gMLVSS·d),而在同样条件下, CSTR达到乙醇型发酵后,比产氢速率仅为0.06L/(gMLVSS·d).ABR通过生物相的分离,使产氢系统梯级利用有机物并达到深度产氢的目的.与CSTR相比,ABR具有较高的产氢活性、较低能源消耗等优点,是一种较为理想的有机废水发酵制氢反应设备.     

三峡库区主要水域典型抗生素分布及生态风险评估

为评价三峡库区主要水域典型抗生素的污染状况和生态风险,利用固相萃取-高效液相色谱-串联三重四极杆质谱联用法（SPE-HPLC-MS/MS）,分析三峡库区长江干流和6条支流表层水体中6类28种抗生素的质量浓度,根据欧盟环境风险评价方法计算RQ_S（风险商值）及RQ_sum（联合风险商值）,并按照Hernando等提出评级方法评价研究区域的生态风险等级.结果表明:三峡库区7条河流共检出4类10种抗生素,质量浓度范围为0.6~218.0 ng/L,其中除OFX（氧氟沙星）和CAP（氯霉素）外,其余8种[SDI（磺胺嘧啶）、SMX（磺胺甲唑）、SMZ（磺胺二甲嘧啶）、ERM（红霉素）、ROM（罗红霉素）、TYL（泰乐菌素）、FF（氟苯尼考）、LIN（林可霉素）]均为畜禽药品,并且FF、LIN在我国畜禽药品中使用量排名居前五位.7条河流抗生素RQ_sum由高到低依次为濑溪河>琼江>綦江>碧溪河>嘉陵江>长江>乌江,其中,濑溪河RQ_sum高达5.532,SMX、ERM和OFX均为高风险,说明其对濑溪河水体中相应的水生生物表现出较高的毒性风险;琼江、綦江、碧溪河和嘉陵江的RQ_sum均处于1~2之间,表现出较高生态风险,但4条河流检出抗生素的单个RQ_S均小于1,处于低风险;长江的RQ_sum为0.605,检出抗生素中TYL、ERM和ROM处于中风险,其余为低风险;乌江的RQ_sum为0.013,检出抗生素均处于低风险,说明水体受人类活动干扰最小.研究显示,三峡库区主要水域中抗生素含量略低于其他水域,但应进一步强化对畜禽养殖行业抗生素使用的监管,开展畜禽粪污还田技术规范中抗生素含量限制的相关研究.