Heavy metal bioaccumulation in selected medicinal plants collected from Khetri copper mines and comparison with those collected from fertile soil in Haridwar,India

Heavy metal distribution in medicinal plants is gaining importance not only as an alternative medicine, but also for possible concern due to effects of metal toxicity. The present study has been focused on emphasizing the heavy metal status and bioaccumulation factors of V, Mn, Fe, Co, Cu, Zn, Se (essential metals) and Cr, Ni, Cd, As and Pb (potentially toxic metals) in medicinal plants grown under two different environmental conditions e.g., near to Khetri copper mine and those in fertile soils of Haridwar, both in India, using Instrumental Neutron Activation Analysis (relative method) and Atomic Absorption Spectrometry. The copper levels in the medicinal plants from Khetri were found to be 3-4 folds higher (31.6–76.5 mg kg^?1) than those from Haridwar samples (7.40–15.3 mg kg^?1), which is correlated with very high copper levels (763 mg kg^?1) in Khetri soil. Among various heavy metals, Cr (2.60–5.92 mg kg^?1), Cd (1.47–2.97 mg kg^?1) and Pb (3.97–6.63 mg kg^?1) are also higher in concentration in the medicinal plants from Khetri. The essential metals like Mn (36.4–69.3 mg kg^?1), Fe (192–601 mg kg^?1), Zn (24.9–49.9 mg kg^?1) and Se (0.13–0.91 mg kg^?1) and potentially toxic metals like Ni (3.09–9.01 mg kg^?1) and As (0.41–2.09 mg kg^?1) did not show much variations in concentration in the medicinal plants from both Khetri and Haridwar. The medicinal plants from Khetri, e.g., Ocimum sanctum, Cassia fistula, Withania somnifera and Azadirachta Indica were found rich in Ca and Mg contents while Aloe barbadensis showed moderately high Ca and Mg. Higher levels of Ca-Mg were found to correlate with Zn (except Azadirachta Indica). The bioaccumulation factors (BAFS) of the heavy metals were estimated to understand the soil-to-plant transfer pattern of the heavy metals. Significantly lower BAF values of Cu and Cr were found in the medicinal plants from Khetri, indicating majority fraction of these metals are precipitated and were immobilized species unsuitable for plant uptake. Overall, Withania somnifera (Ashwagandha) showed very high metal bioaccumulation.     

Effect of environmental forcing on the fate of nutrients, dissolved organic matter and heavy metals released by a coastal wastewater pipeline

Discharges of nutrients, urea, dissolved organic matter and heavy metals by a sewage underwater pipeline are analysed in comparison to environmental conditions in a shallow coastal zone. Variable thermo-haline stratifications of the water column and currents in upper (2.62-34.97 cm s^-1) and deeper (0.83-10.91 cm s^-1) layers drive vertical diffusion and lateral transport of wastewaters. Loads of reactive phosphorus (0.13 tons d^-1) and ammonium (1.62 tons d^-1) by the pipeline are not negligible compared to the major river loads in the gulf. High concentrations of urea (≤11.51 μmol N dm^-3) were found in the area of wastewater release. Ammonium uptake (6.14-534 nmol N dm^-3 h^-1) strongly exceeded nitrate uptake (0.19-138 nmol N dm^-3 h^-1), indicating that discharges of ammonium by the pipeline are actively assimilated by plankton community even at low levels of light. Distribution of Zn (≤27.7 ppb), Cu (≤25.6 ppb), Cd (≤0.80 ppb) and Pb (≤13.5 ppb) in the water column and the measurement of their complex-forming capacity in seawater did not indicate a persistent perturbation of the pelagic environment due to heavy metals.     

NITROGEN AND PHOSPHORUS IN SURFACE WATERS OF THE UPPER COLORADO RWER BASIN1

ABSTRACT: As part of a basinwide water-quality study, nitrogen and phosphorus data for the Upper Colorado River Basin from the Colorado-Utah State line to the Continental Divide were analyzed for spatial distributions, concentrations associated with various land uses, and temporal trends. Nitrogen and phosphorus concentrations generally increased in a downstream direction. Some nutrient concentrations were elevated at some sites in the upper parts of the basin in areas influenced by increasing urbanization. Sites were grouped according to land use and site type, and median nutrient concentrations were compared among groups. Sites within the agricultural areas of the basin generally had the highest concentrations of nitrogen and phosphorus; concentrations for main-stem, tributary, and urbanization sites were slightly lower than for the agricultural sites. Background sites, or sites with minimal land-use impacts, had very low median nutrient concentrations. Several sites with long-term data were analyzed for temporal trends in concentrations. Several statistically significant downward trends of low and moderate magnitude were observed for nitrogen and phosphorus species. No upward trends were observed in the data at any site.     

乡镇工业电镀行业主要污染物排放量的估算方法

电镀分有氰电镀与无氰电镀两类。乡镇工业电镀行业的环境污染最主要是氰污染和铬污染。本文针对乡镇电镀行业的特点,调查了湖南省沅江市、四川省新都县、湖北省黄陂县、汉川县以及江苏省部分县市乡镇电镀厂,将收集资料及实际监测资料进行回归分析,得出乡镇电镀行业的污染物发生量大小与原材料的消耗有关,可以用多元回归方程估算乡镇电镀行业主要污染物发生量。这一估算方法简单易行,实用可靠,操作方便。     

应用指数平滑法建立城市工业三废排放量预测模型

指数平滑法是常用的一种时间序列预测方法，但用于环境预测的先例则较少。本文以南通市１９８１－１９９０年工业三废排放量时间序列为例，简要介绍了该法的原理以及平滑计算、建模、预测和精度分析的过程，并对其在环境预测中的应用效果进行了探讨，结果表明，该法与目前环境预测中常用的回归法相比，具有数据来源较易，不需要特殊分布，计算简单，精度较高等明显的优点，充分显示出该法在环境预测中应用的可行性。     

Absorption characteristics of new solvent based on a blend of AMP and 1,8-diamino-p-menthane for CO2 absorption

Aqueous 1,8-diamino-p-menthane (KIER-C3) and commercially available amine solutions were tested for CO₂ absorption. A 2-amino- 2-methyl-1-propanol (AMP) solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO₂ than the AMP solution with an addition of monoethanolamine (MEA) and ammonia (NH₃), respectively. The reaction rate constant for CO₂ absorption by the AMP/KIER-C3 solution was determined by the following equation: k_2,AMP/C3 = 7.702×10⁶ exp (-2248.03/T). A CO₂ loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO₂ absorption capability of AMP.     

Nitrogen deposition alters soil chemical properties and bacterial communities in the Inner Mongolia grassland

Nitrogen deposition has dramatically altered biodiversity and ecosystem functioning on the earth; however, its effects on soil bacterial community and the underlying mechanisms of these effects have not been thoroughly examined. Changes in ecosystems caused by nitrogen deposition have traditionally been attributed to increased nitrogen content. In fact, nitrogen deposition not only leads to increased soil total N content, but also changes in the NH₄⁺-N content, NO₃^--N content and pH, as well as changes in the heterogeneity of the four indexes. The soil indexes for these four factors, their heterogeneity and even the plant community might be routes through which nitrogen deposition alters the bacterial community. Here, we describe a 6-year nitrogen addition experiment conducted in a typical steppe ecosystem to investigate the ecological mechanism by which nitrogen deposition alters bacterial abundance, diversity and composition. We found that various characteristics of the bacterial community were explained by different environmental factors. Nitrogen deposition decreased bacterial abundance that is positively related to soil pH value. In addition, nitrogen addition decreased bacterial diversity, which is negatively related to soil total N content and positively related to soil NO₃^--N heterogeneity. Finally, nitrogen addition altered bacterial composition that is significantly related to soil NH₄⁺-N content. Although nitrogen deposition significantly altered plant biomass, diversity and composition, these characteristics of plant community did not have a significant impact on processes of nitrogen deposition that led to alterations in bacterial abundance, diversity and composition. Therefore, more sensitive molecular technologies should be adopted to detect the subtle shifts of microbial community structure induced by the changes of plant community upon nitrogen deposition.     

不同曝气强度下SBMBBR和SBR脱氮除磷性能对比研究

对比考察了不同曝气强度下序批式活性污泥反应器(SBR)和序批式移动床生物膜反应器(SBMBBR)的脱氮除磷效果,并分析了反应器单个周期内有机物、氮和磷的转化过程.实验结果表明,SBMBBR和SBR脱氮主要是基于好氧段发生的同步硝化反硝化(SND)及进水、搅拌阶段发生的缺氧反硝化途径实现的,而除磷是基于常规生物除磷和反硝化除磷过程而完成.曝气强度会影响SBR和SBMBBR好氧阶段SND发生的程度,最佳曝气强度下两者通过SND作用去除的TN量分别达到去除总量的47.7%和79.0%.在采用先行厌氧的运行方式,保持系统内高浓度微生物,使反应器在进水C/N比只有2.2～3.5的条件下均取得了良好的脱氮除磷效果.两者相比,SBMBBR和SBR在COD和NH4-N去+除方面没有差异,而SBMBBR的反硝化、除磷效果更优,TN、TP去除率分别达到95.4%和93.5%,较SBR分别高出10.9%和4.1%.     

基于BDPs的多级土壤渗滤系统处理受污染河水的试验研究

针对受污染的流入滇池的河流河水,采用具有曝气段和缺氧段的两段式多级土壤渗滤(multi-soil-layering,MSL)系统,开展了在缺氧段添加非水溶性可生物降解多聚物(BDPs)材料PBS颗粒的强化脱氮除磷研究.结果表明,添加PBS碳源可有效解决传统MSL系统因碳源不足而导致的脱氮效果不理想的问题.在河水污染较轻及较重两种情况下,系统对TN的平均去除率分别达到78%、85%,平均单位表面去除负荷分别为9.09g·m-·2d-1、24.55g·m-·2d-1;TP平均去除率分别达到92%、98%,平均单位表面去除负荷分别为0.76g·m-·2d-1、2.02g·m-·2d-1.此外,系统对COD的平均去除率可达到75%以上.     

博斯腾湖夏季水下光场特征分析及影响因素探讨

2011年8月,在新疆博斯腾湖17个站点进行水样采集,同步对11个站点进行水下光场原位测定.结果发现,博斯腾湖夏季总颗粒物吸收系数光谱表现出明显的浮游植物吸收特征,而浮游植物光谱曲线有明显的硅藻吸收光谱特征.在光合有效辐射波段,有色可溶性有机物（CDOM）吸收系数与浮游植物吸收系数对总吸收的贡献相当,而非色素颗粒物对总吸收的贡献最低.水下光谱衰减系数的最小值出现在580nm左右的绿光波段,PAR漫射衰减系数平均值为0.53m-1,平均真光层深度约为9.69m,大于湖水平均深度.在博斯腾湖虽然纯水和CDOM在总吸收中占有很重要的部分,但主导漫射衰减的因子仍为颗粒物.通过本文研究,以期能为干旱地区湖泊环境保护和水质遥感监测提供数据和理论基础.