Characterization of phosphorus species and modeling for its organic forms in eutrophic shallow lake sediments,North China

Variations of phosphorus （P） and its species in surface sediment of Baiyangdian Lake, a eutrophic shallow lake located in North China, were investigated through combination of field survey and numerical calculation based on cluster analysis. P fractionation was performed by a sequential extraction scheme, categorized as loosely bound P （NH4Cl-P）, reductant soluble P （BD-P）, metallic oxide bound P （NaOH-P）, calcium bound P （HCl-P） and organic P （Org-P）. P concentrations exhibited regional similarities and a total of four sub-areas were identified in which the same rank was HCl-P 〉 Org-P 〉 BD-P ,=NaOH-P 〉NH4Cl-E NH4Cl-P, BD-P and Org-P were found to contribute to P enrichment in overlying water column. Specifically, labile Org-P acted as a potential pool with a greater contribution in aerobic layer compared to anaerobic layer. A hysteresis （lag = 4 months） existed when labile Org-P concentration was negatively correlated with aerobic layer thickness. In view of magnitude of identified P contributors in sub-areas, higher potential of P release was present in Fuhe River and Tang River estuary areas. On the basis of calibration and verification, the mathematical model with parameter settings applied in this study was improved to serve as a tool for limnology management and eutrophic control.     

Characterization studies of a semi‐automated separation method for analysis of non‐ortho substituted polychlorinated biphenyl (PCB) congeners in environmental samples

Non‐ortho substituted polychlorinated biphenyl (PCB) congeners can account for the majority of the dioxin‐like toxicity in environmental samples, yet analysis for these congeners is difficult because other PCB congeners co‐elute with them in most Chromatographic methods. An automated method was developed which incorporates a porous graphitic carbon (PGC) column which is commercially available. Non‐ortho substituted congeners were successfully separated from interfering PCB congeners. Recoveries of non‐ortho substituted congeners were consistently reproducible (CV < 9%) when chicken eggs were fortified with individual congeners.     

Effect of acid rain on the fractionation of heavy metals and major elements in contaminated soils

Acid rain is a serious environmental problem worldwide. In the present study, we investigated the effect of acid rain (1:1 equivalent basis H₂SO₄:HNO₃) at pH values of 2.0, 4.0 and 7.0 on the fractionation of heavy metals (Cd, Cu, Fe, Mn, Ni, Pb and Zn) and major elements (K, Na, Ca, and Mg) in contaminated calcareous soils over a 2084 h period. Heavy metals and major elements in soil samples were fractionated before and after 2084 h kinetic release using a sequential extraction procedure. Before kinetic studies the predominant fractions of K, Na, Ca, Mg, Cd and Ni were mainly associated with carbonate fraction (CARB), whereas Fe, Mn and Zn were associated with the Fe–Mn oxide fraction (Fe–Mn oxide). The highest percentage of Pb and Cu were found in the exchangeable (EXC) and organic matter (OM) fractions, respectively. After kinetic study using different simulated acid rain solutions, the major fractions of heavy metals (expect of Cu) and Na was the same as before release. Upon the application of different acid rain solutions, K and Mg were found dominantly in Fe–Mn oxide fraction, whereas Ca was in the EXC fraction. The results provide valuable information regarding metal mobility and indicated that speciation of metals (Cu and Zn) and major elements in contaminated calcareous soils can be affected by acid rain.     

湖泊底泥土地利用对土壤中重金属铅、铜形态影响

采用田区试验研究了田间种植冬小麦条件下,底泥土地利用前后土壤中重金属铅、铜的形态演变及小麦各器官中铅、铜的富集。结果表明,随着底泥施用量的增加,土壤中重金属铅、铜的可交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态、残渣态均有不同程度的增加,本试验所有处理中,可交换态铅的质量分数范围为0.02~0.10 mg·kg-1,碳酸盐结合态铅的质量分数范围为0.04~0.24 mg·kg-1,铁锰氧化物结合态铅质量分数为0.41~1.88 mg·kg-1,有机物结合态铅质量分数范围为1.23~4.92 mg·kg-1,残渣态铅质量分数范围为4.82~23.66 mg·kg-1;各处理与对照相比,可交换态铜质量分数增加了40.00%~200.00%,碳酸盐结合态铜质量分数增加了36.84%~363.16%,铁锰氧化物结合态铜质量分数增加了7.17~45.15%,有机结合态铜质量分数增加了7.98%~62.61%,残渣态铜质量分数增加了0.12%~9.69%,各处理的残渣态铅、铜质量分数均较高。随着底泥用量增加,小麦根系、茎叶、籽粒中铅、铜质量分数均呈增加趋势,植株对重金属铅、铜的富集顺序为根系>茎叶>籽粒,铜的富集系数均大于铅。小麦籽粒产量、茎叶生物量及地上部生物量随着底泥施用量的增加,均出现了先增加后减少的现象,当小麦籽粒产量达到最大值时,籽粒中铅、铜质量分数未超出我国相应标准,依此确定底泥环境安全施用量为3051.29 t·hm-2。     

滤膜对环境空气中砷测定的影响及改进

依据《环境空气和废气 颗粒物中砷、硒、铋、锑的测定 原子荧光法》（HJ 1133—2020）的要求,对采集环境空气中砷的9种滤膜的本底值、回收率、检出限、精密度和准确度进行了实验对比。根据实验各项性能指标及成本考虑,建议选择尼龙、硝酸纤维或混合纤维3种国产有机滤膜,其购买方便、价格较低,方法检出限均为0.2 ng/m³,精密度和准确度均能满足环境空气中砷的测定要求。     

Applying chemical sedimentation process in drinking water treatment plant to address the emergent arsenic spills in water sources

Arsenic (As) spills occurred more frequently and sometimes polluted water sources in recent years in China. It is as urgent need to develop emergency treatment technologies to address the arsenic threat for large-scale water treatment plants. In response, we developed a chemical sedimentation technology to remove arsenic contaminants for water treatment plants. Bench-scale experiments were conducted to investigate the efficiency of arsenic removal and the influencing factors of the chemical sedimentation treatment process. The influencing factors included the choice and dosage of coagulants, the valence of arsenic and pH value of solution. The As(V) contaminants can be almost completely removed by ferric or alum coagulants. The As(III) contaminants are more recalcitrant to chemical sedimentation, 75% for ferric coagulant and 40% for alum coagulant. The quantitative results of arsenic removal load by different ferric or alum coagulants were presented to help determine the parameters for arsenic treatment technology. The dominant mechanism for arsenic removal is static combination, or adsorption of negative arsenic species onto positive ferric hydroxide or alum hydroxide flocs. The efficiency of this treatment technology has also been demonstrated by a real production test in one water treatment plant with arsenic-rich source water and one emergency response. This technology was verified to be quick to set-up, easy to operate and highly efficient even for high concentration of arsenic.     

天然水体溶解性有机物(DOM)分级组分对典型城市源污染的荧光响应

运用化学(树脂)分级方法和三维荧光光谱技术,从总体溶解性有机物(DOM)到DOM各分级组分,逐步深入考察其总体分级特征及各组分三维荧光特征对典型城市生活源污染的响应特征和机理. 总体DOM分级特征对污染的产生和变化响应较弱,而DOM的分级组分对生活源污染具有较好的响应特性. DOM的总体分级特征表明,无污染的源头水DOM中以憎水酸(HoA)为主(相对含量最高),其次为亲水性物质(HiM),而受污染水体DOM中的憎水性碱和中性物质(HoBN)及弱憎水酸(WHoA)的绝对含量和相对含量均明显增高,表明用HoBN和WHoA组分相对含量的增加指示污染的增加具有一定的可行性. 研究各分级组分的三维荧光光谱结构特征表明,HoA,HoBN及HiM均对城市源污染具有良好的响应特性,受污染水体的HoA和HoBN组分荧光特征信息更为突出和丰富,且主要为具有紫外吸收的生物代谢类蛋白物质;最为特异的是WHoA组分,其在源头水中主要为含共轭结构的富里酸类物质,而在受污染水体中该类物质几乎消失且荧光响应也急剧降低. 分析式分级法获得的水体DOM主要分级组分对城市源污染具有较好的响应特性.      

稀土在土壤-植物系统中的分馏效应及影响因素

以稀土背景较高的红壤为供试土壤,采用小麦盆栽实验,研究了稀土元素在土壤～小麦系统中的分馏模式,考察了外源稀土浓度、腐殖酸浓度和土壤酸度对稀土分馏模式的影响.结果发现,红壤中稀土的分馏模式与我国土壤的稀土分馏模式基本一致,为向右倾斜的轻稀土富集模式.小麦根部的稀土分布模式与土壤类似,小麦茎叶中稀土分布模式则有所不同.加入外源稀土后,小麦根部的稀土分馏模式随土壤中稀土丰度的改变而改变,而小麦茎叶中的稀土分馏模式却保持相对稳定,说明小麦地下部分与小麦地上部分对稀土的吸收方式存在差异.腐殖酸对稀土在土壤-小麦系统中的分馏效应影响不大土壤酸度对稀土在土壤-小麦系统中的分馏效应有一定的影响,在所试验条件下,观察到小麦中稀土元素的分馏系数随pH值降低而降低,高pH值(pH＝6.7)使稀土在小麦中的分馏系数加大.     

二氧化锰对As(Ⅲ)的氧化及其对针铁矿去除水体中As(Ⅲ)的影响

研究了合成钠水锰矿(δ-MnO2)对As(Ⅲ)的氧化作用并与商品MnO2的结果进行了比较,结果表明,δ-MnO2不仅对As(Ⅲ)有很强的氧化能力,而且对溶液中的砷也具有一定的吸附能力,而商品MnO2对As(Ⅲ)的氧化能力很弱.当有δ-MnO2存在时,针铁矿对As(Ⅲ)的去除效率提高,δ-MnO2的促进作用随体系pH的增加而增加,约在pH为6.0达最大,随后又逐渐减小,说明近中性条件下,δ-MnO2的促进作用最强.     

水体溶解性有机物的化学分级表征:原理与方法

综述了水体溶解性有机物(DOM)的化学分级表征法即树脂吸附分级法(RA)的研究与进展,同时基于该方法存在的一些问题结合我国典型水质体系,从树脂的选择、净化、分级的定义、水样过柱流速、水样树脂体积比的确定等方面进行了研究探讨,给出了完整的实验参数和操作方法.