Probability of intellectual disability is associated with soil concentrations of arsenic and lead

Background

The association between metals in water and soil and adverse child neurologic outcomes has focused on the singular effect of lead (Pb), mercury (Hg), and arsenic (As). This study describes the complex association between soil concentrations of As combined with Pb and the probability of intellectual disability (ID) in children.

Methods

We used a retrospective cohort design with 3988 mother child pairs who were insured by Medicaid and lived during pregnancy and early childhood in South Carolina between 1/1/97 and 12/31/02. The children were followed until 6/1/08, using computerized service files, to identify the diagnosis of ID in medical records and verified by either school placement or disability service records. The soil was sampled using a uniform grid and analyzed for eight metals. The metal concentrations were interpolated using Bayesian Kriging to estimate concentration at individual residences.

Results

The probability of ID increased for increasing concentrations of As and Pb in the soil. The Odds Ratio for ID, for one unit change in As was 1.130 (95% confidence interval 1.048-1.218) for Pb was 1.002 (95% confidence interval 1.000-1.004). We identified effect modification for the infants based on their birth weight for gestational age status and only infants who were normal size for their gestational age had increased probability of ID based on the As and Pb soil concentrations (OR for As at normal weight for gestational age = 1.151 (95% CI: 1.061-1.249) and OR for Pb at normal for gestational age = 1.002 (95% CI: 1.002-1.004)). For normal weight for gestational age children when As = 22 mg kg⁻¹ and Pb = 200 mg kg⁻¹ the risk for ID was 11% and when As = 22 mg kg⁻¹and Pb = 400 mg kg⁻¹ the probability of ID was 65%.

Conclusion

The probability of ID is significantly associated with the interaction between Pb and As for normal weight for gestational age infants.     

壳聚糖的物理/化学改性及其对含酚废水的处理

将壳聚糖物理改性为球形颗粒,然后在微波辐射下,球形壳聚糖与柠檬醛接枝反应,再与NaBH4还原反应,制备一种新型环保材料--物化改性壳聚糖.采用红外光谱仪(IR)、X衍射仪(XRD)、电子显微镜(SEM)和比表面测定及孔径分析仪(BET)结构表征改性壳聚糖.通过含酚制药废水的动态小柱吸附实验,研究了时间、柱高和出水流速等...     

改性建筑垃圾作为橡胶填料的可行性研究

将废旧混凝土和废粘土砖经湿式表面改性后作为橡胶填料,辅以配合剂与丁苯橡胶进行混炼、硫化制得橡胶组合物,并将其与以等量轻质碳酸钙作为填料,按相同配比混炼、硫化制得的橡胶组合物的性能进行比较.结果表明,将加工成微米级别(0.5～12.0 μm)的建筑垃圾(废旧混凝土或废粘土砖)经水解双(三乙氧基硅基丙基)四硫化物(KH-8...     

改性粉煤灰合成沸石对甲基橙的吸附动力学

以粉煤灰(FA)为原料,采用水热晶化一步法制备了Na P1型沸石(ZFA),对合成产物的结构进行了表征,并采用阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)对其进行改性。通过静态吸附实验,研究了改性后Na P1型沸石(MZFA)对水溶液中甲基橙的吸附特性,从动力学角度探讨了吸附机理。结果表明,在所研究的浓度条件下,改性Na P1型沸石对甲基橙的吸附符合Langmuir等温吸附方程,在25℃时,静态饱和吸附量(Qm)为64.76 mg/g。动力学分析表明,改性Na P1型沸石对溶液中甲基橙的吸附符合准二级动力学模型。     

碱熔融—微波晶化法合成粉煤灰沸石及其对Cd2+的吸附

以粉煤灰为主要原料,采用碱熔融—微波晶化法合成粉煤灰沸石。采用XRD,SEM,TEM等技术表征了粉煤灰沸石的微观结构,并对其吸附Cd²⁺的性能进行了研究。表征结果显示,粉煤灰沸石主要由X型沸石、P型沸石和铝组成,粉煤灰沸石中有排列规则、呈蜂窝状的孔穴和孔道存在,其孔穴和孔道大小分布均匀,致密。粉煤灰沸石的比表面积为108.49 m²/g,平均孔径为3.779 nm,孔体积为0.221 mL/g。实验结果表明,在溶液pH为7、吸附时间30 min的最佳吸附条件下,Cd²⁺去除率均大于94%。粉煤灰沸石对Cd²⁺的吸附可很好地用二级动力学方程进行拟合,相关系数为0.999 99。可用Langmuir等温吸附模型描述该吸附过程,该吸附过程是单分子层吸附,主要是化学吸附,粉煤灰沸石对Cd²⁺的饱和吸附量为49.261 mg/g。     

Adsorption of simazine on zeolite H-Y and sol–gel technique manufactured porous silica: A comparative study in model and natural waters

In this work, we studied the removal of simazine from both a model and well water by adsorption on two different adsorbents: zeolite H-Y and a porous silica made in the laboratory by using the sol–gel technique. The pH dependence of the adsorption process and the isotherms and pseudo-isotherms of adsorption were studied. Moreover, an iterative process of simazine removal from both the model and well water, which allowed us to bring the residual simazine concentration below the maximum concentration (0.05 mg L^?1) of agrochemicals in wastewater to be released in surface waters or in sink allowed by Italian laws, was proposed. The results obtained were very interesting and the conclusions drawn from them partly differed from what could reasonably be expected.     

MANAGEMENT OF INSTREAM FLOWS THROUGH RUNOFF DETENTION AND RETENTION1

ABSTRACT: The use of reservoirs and land treatments to manage streamflow for the maintenance or enhancement of instream flow values is a valid concept. Historically, large reservoirs have been used for flood control and water-supply regulation. Smaller structures have enjoyed widespread use for soil and water conservation in headwater areas. Where reservoir releases can be controlled, it is technically feasible to regulate flows for the enhancement of instream values. However, institutional and political obstacles may preclude the operation of some reservoirs for this purpose. Retention and detention structures and land treatments, implemented for soil and water conservation purposes, have often had favorable effects on the streamflow hydrograph. Decreases in peak flows and increases in low flows have been documented. Design concepts for runoff-control structures are discussed in relation to instream flow management objectives. Hydro-logic simulation is offered as a potential tool for project design and feasibility analysis.     

Profitability of in-plant modifications in pollution control

This case study was developed in view of setting up a demonstration project on “revealing the profitability of clean technology in small-scale electroplating unit”. The research was conducted in a small-scale electroplating shop located in Bangkok. A set of simple in-plant control measures such as dragout recovery, spray rinsing technique and rinse water agitation were implemented. Quantitative data, obtained from the monitoring of wastewater before and after process modifications, have indicated a substantial reduction both in quantity and strength of wastewater generated. Water consumption was reduced by approx. 35% of total rinsing water, which is 19% of total process water consumption. Average metal concentrations in wastewater was reduced 73% for Cr-, 71% for Ni- and 54% for Cu-plating rinse water.     

复合无机防火涂料优配研究

以市售无机膨胀型AB牌防火涂料为研究基础,复合了膨胀阻燃剂(APP-MEL-PER阻燃体系)、抑烟剂和助剂,进行了新型防火涂料的制备,当膨胀阻燃体系(APP-MEL-PER阻燃体系)以17∶6∶6的配比混合于该涂料中,其所占质量百分比为19%的时,防火性能最好。测试表明,该新型防火涂料烟密度等级6.77,指数下降了10,接近于国家标准1级。在248℃~400℃期间失重仅为12%,在390℃,有强烈的吸收峰,也表现了优异的阻燃性能。实现了APP-MEL-PER膨胀阻燃剂和AB牌涂料优配的目的。     

SPATIAL VARIATION OF PRECIPITATION ON THE TEXAS HIGH PLAINS1

ABSTRACT: Space autocorrelation techniques have been used to reveal the nature and spatial distribution of precipitation in the Texas High Plains. Correlation in precipitation amounts varies with both distance and direction, dropping off rapidly with distance, particularly during the warm season. The analyses can be used to estimate storm characteristics in conjunction with a wide variety of problems dealing with irrigation, crop yields, drainage and water supply, and evaluation of artificial weather modification efforts.