The residues, distribution, and partition of organochlorine pesticides in the water, suspended solids, and sediments from a large Chinese lake (Lake Chaohu) during the high water level period

The levels of organochlorine pesticides (OCPs) in the water, suspended solids, and sediments from Lake Chaohu during the high water level period were measured by a solid-phase extraction gas chromatograph–electron capture detector. The spatial distributions of the three phases and the water/suspended solids and sediment/water partition coefficients were analyzed. The results showed the following: (1) The mean contents of OCPs in the water, suspended solids, and sediments were 132.4?±?432.1 ng/L, 188.1?±?286.7 ng/g dry weight (dw), and 13.7?±?9.8 ng/g dw, respectively. The dominant OCP components were isodrin (85.1 %) for the water, DDTs (64.4 %) for the suspended solids, and both isodrin (48.5 %) and DDTs (31.8 %) for the sediments. (2) β-HCH was the primary isomer of HCHs in the water and sediments, and the proportions were 61.7 and 41.3 %; γ-HCH was the primary isomer in the suspended solids, accounting for 49.3 %; p,p′-DDT was the dominant content of DDTs in the water and suspended solids, whereas p,p′-DDD was the main metabolite of DDTs in the sediments. (3) The concentrations of contaminants in the water from the western lake were greater than those from the eastern lake, but the concentrations in the suspended solids from the western lake were less than those from the eastern lake. (4) There was no significant correlation between the water–suspended solids partition coefficient K _d and the n-octanol–water partition coefficient K _ow, and between the sediment–water organic-C weighted sorption coefficients K _oc and K _ow.     

Effects of input uncertainty and variability on the modelled environmental fate of organic pollutants under global climate change scenarios

Global climate change (GCC) is expected to influence the fate, exposure and risks of organic pollutants to wildlife and humans. Multimedia chemical fate models have been previously applied to estimate how GCC affects pollutant concentrations in the environment and biota, but previous studies have not addressed how uncertainty and variability of model inputs affect model predictions. Here, we assess the influence of climate variability and chemical property uncertainty on future projections of environmental fate of six polychlorinated biphenyl congeners under different GCC scenarios using a spreadsheet version of the ChemCAN model and the Crystal Ball® software. Regardless of emission mode, results demonstrate: (i) uncertainty in degradation half-lives dominates the variance of modelled absolute levels of PCB congeners under GCC scenarios; (ii) when the ratios of predictions under GCC to predictions under present day climate are modelled, climate variability dominates the variance of modelled ratios; and (iii) the ratios also indicate a maximum of about a factor of 2 change in the long-term average environmental concentrations due to GCC that is forecasted between present conditions and the period between 2080 and 2099. We conclude that chemical property uncertainty does not preclude assessing relative changes in a GCC scenario compared to a present-day scenario if variance in model outputs due to chemical properties and degradation half-lives can be assumed to cancel out in the two scenarios.     

固定化微生物修复石油污染土壤影响因素研究

针对石油污染土壤修复,利用实验室已筛选的高效石油降解单菌SM-3,以天然有机材料为载体,吸附法制备固定化微生物。将游离与固定化微生物应用于室内花盆模拟修复石油污染土壤,对C/N/P、微生物投加量、石油含量、氧化剂和表面活性剂设计5因素4水平正交实验,探讨不同修复时期各影响因素的重要性顺序,最佳条件下各菌株的修复效果。结果表明,不同微生物在不同降解时期,各影响因素的重要性会发生变化;经过21 d的修复,固定化单菌SM-3石油降解率为22.77%,修复过程中,接种量是最重要的影响因素,营养元素N、P投加影响较大,表面活性剂和氧化剂影响次之。     

改善环保疏浚底泥脱水干化效能的实验研究

采用以硫酸亚铁(FeSO4)为主要成分的复合脱水剂作为疏浚泥浆脱水剂(以下简称脱水剂),黄沙、炉渣、煤灰、石灰和粉煤灰分别作为疏浚底泥干化改良剂进行实验研究。结果表明,在脱水剂投加量为100 mg/L条件下,可以提高沉淀效率约20%;在投加脱水剂及5%石灰、粉煤灰、炉渣改良剂的条件下,底泥比阻值下降50%～70%;初期渗水速率提高6%～68%;与原泥相比,以黄沙、炉渣、煤灰为改良剂的底泥,经过4个月干化期后,承载力提高了30%～150%。本研究为疏浚底泥快速脱水干化提供了一种可行的技术途径。     

新制备生物炭的特性表征及其对石油烃污染土壤的吸附效果

生物炭作为一种绿色环保的功能材料因其在污水处理和污染土壤修复方面具有显著效果而受到极大关注.采用红外光谱、元素分析仪及微孔分析对不同温度(200、300、400、500和600℃)条件下制备的木屑和麦秆生物炭进行特性表征,并采用制备的生物炭净化石油污染土壤,分别考察了污染物性质、生物质原料和热解温度对其净化效果的影响.结果表明,随着热解温度的增高,生物炭芳香化程度增加,极性降低,微孔结构逐渐发育,表面积增大.加入生物炭33 d后,污染土壤中总石油烃及其组分烷烃的浓度比对照略有降低,而PAHs浓度下降显著.随着热解温度升高,2种生物炭对PAHs的吸附强度均逐渐增大,芳香度增高、表面积增大是强吸附的主要原因.2种生物炭在400℃及以下温度制备时对PAHs的吸附强度为:木屑生物炭＞麦秆生物炭;而400℃以上温度制备的生物炭吸附强度则相反,即麦秆生物炭＞木屑生物炭,说明生物炭原料对其吸附强度也具有显著影响.     

Pollution characteristics of 23 veterinary antibiotics in livestock manure and manure-amended soils in Jiangsu province,China

The aim of this study was to investigate the pollution characteristics of typical veterinary antibiotics in manure and soil of livestock farms in Jiangsu province. This investigation employed solid-phase extraction (SPE) coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A total of 53 manure and 50 amended soil samples from 16 livestock farms in Jiangsu province were collected for analysis. In the manure samples, the highest detected frequencies and concentrations were those of tetracyclines (TCs, 54.1 ± 5775.6 μgkg^?1), followed by fluoroquinolones (FQs, 8.4 ± 435.6 μgkg^?1), sulphonamides (SAs, 3.2 ± 5.2 μgkg^?1) and macrolides (MACs, 0.4 ± 110.5 μgkg^?1). Statistical analysis was used to illuminate the pollution characteristics of 23 veterinary antibiotics for various animal types and different regions in Jiangsu province. The results showed that the pollution level in cow manure was relatively lower compared with pig and chicken manure due to the relative restriction of medication. Furthermore, contamination was serious in amended soil from chicken farms. The pollution level in manure among different regions was higher to the south and north compared with the centre of the region. The same outcome was found for soil. Antibiotic residues in organic fertilizer were also investigated in this study. We found that although the detected concentration was lower in organic fertilizer than in fresh manure, detection frequencies (10–90%) were high, especially for roxithromycin (90%) in MACs (30–90%). This finding suggests attention should be paid to the pollution levels in organic fertilizer. This study is the first extensive investigation of the occurrence and distribution of many kinds of typical veterinary antibiotics in manure and soil from livestock farms of Jiangsu province. This investigation systematically assesses veterinary antibiotics usage and related emissions in southeast China.     

Current status and historical variations of phthalate ester (PAE) contamination in the sediments from a large Chinese lake (Lake Chaohu)

The residual levels of phthalate esters (PAEs) in the surface and two core sediments from Lake Chaohu were measured with a gas chromatograph–mass spectrometer (GC–MS). The temporal–spatial distributions, compositions of PAEs, and their effecting factors were investigated. The results indicated that di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl) phthalate (DEHP) were three dominant PAE components in both the surface and core sediments. The residual level of total detected PAEs (∑PAEs) in the surface sediments (2.146?±?2.255 μg/g dw) was lower than that in the western core sediments (10.615?±?9.733 μg/g) and in the eastern core sediments (5.109?±?4.741 μg/g). The average content of ∑PAEs in the surface sediments from the inflow rivers (4.128?±?1.738 μg/g dw) was an order of magnitude higher than those from the lake (0.323?±?0.093 μg/g dw), and there were similar PAE compositions between the lake and inflow rivers. This finding means that there were important effects of PAE input from the inflow rivers on the compositions and distributions of PAEs in the surface sediments. An increasing trend was found for the residual levels of ΣPAEs, DnBP, and DIBP from the bottom to the surface in both the western and eastern core sediments. Increasing PAE usage with the population growth, urbanization, and industrial and agricultural development in Lake Chaohu watershed would result in the increasing production of PAEs and their resulting presence in the sediments. The significant positive relationships were also found between the PAE contents and the percentage of sand particles, as well as TOC contents in the sediment cores.     

Cadmium (Cd) distribution and contamination in Chinese paddy soils on national scale

Rice is a staple food by an increasing number of people in China. As more issues have arisen in China due to rice contaminated by cadmium (Cd), Cd contamination in arable soils has become a severe problem. In China, many studies have examined Cd contamination in arable soils on a national scale, but little studies have focused on the distribution of Cd in paddy fields. This study explored the spatial pattern of Cd in paddy soils in China, made a preliminary evaluation of the potential risk, and identified the most critically contaminated regions based on the domestic rough rice trade flow. The results showed that Cd concentrations in paddy soils in China ranged from 0.01 to 5.50 mg/kg, with a median value of 0.23 mg/kg. On average, the highest Cd concentrations were in Hunan (0.73 mg/kg), Guangxi (0.70 mg/kg), and Sichuan (0.46 mg/kg) provinces. Cd concentrations in paddy soils in central and western regions were higher than those in eastern regions, especially the southeastern coastal regions. Of the administrative regions, Cd standard exceedance rate was 33.2 %, and the heavy pollution rate was 8.6 %. Regarding to Cd of paddy soil, soil environmental quality was better in Northeast China Plain than in Yangtze River Basin and southeastern coastal region. Mining activities were the main anthropogenic pollution source of Cd in Chinese paddy soil. Based on rice trade, more of the Chinese population would be exposed to Cd through intake of rice produced in Hunan province. Certain regions that output rice, especially Hunan province, should be given priority in the management and control of Cd contamination in paddy soil.     

Cr(Ⅵ)污染土壤的热解还原无害化处理

提出了用热解还原法对含铬土壤进行无害化处理的新技术,研究了热解温度、热解时间及土壤有机质对铬无害化处理的影响,分析了热解前后土壤中铬的元素形态的变化.同时还探讨了热解还原过程中Cr(Ⅵ)的无害化机制.结果表明,土壤中的有机质在热解还原过程中产生的挥发分对Cr(Ⅵ)的无害化起核心作用;在200～600℃范围内,Cr(Ⅵ)的还原量随着热解温度升高而增大,500.0℃最适合于经济有效地实现Cr(Ⅵ)的热解还原处理;Cr(Ⅵ)的热解还原过程较快.铬的形态分析结果表明,热解后可交换态和碳酸盐结合态铬量大大降低,大部分铬转化成了活性低的残渣态,极大地降低了铬的危害.