Sources and Ecological Risks of Heavy Metals in Soils Under Different Land Uses in Bangladesh

Soil heavy metal pollution, influenced by both natural and anthropogenic factors, significantly reduces environmental quality. In this study, Cr, Ni, Cu, As, Cd, and Pb in eight different land-use soils from Patuakhali District in Bangladesh were assessed. Concentrations of Cr, Ni, Cu, As, Cd, and Pb in soils were 1-87, 5-271, 4-181, 0-80, 0.2-24.0, and 5-276 mg kg^-1, respectively, measured using an inductively coupled plasma-mass spectrometer. The enrichment factor, pollution load index (PLI), and contamination factor (C_fⁱ) of metal i were used to assess the ecological risk posed by metals in soils. The PLI ranged from 0.78 to 2.66, indicating baseline levels to progressive deterioration of soil due to metal contamination. However, C_fⁱ of Cd ranged from 1.8 to 12.0, which showed that the studied soils were strongly impacted by Cd. Considering the severity of the potential ecological risk of a single metal, the descending order was Cd > As > Pb > Cu > Ni > Cr. Soils under all land uses showed moderate to very high potential ecological risk.     

Bacteria and antibiotic resistance detection in fractures of wild birds from wildlife rehabilitation centres in Spain

Anatomic adaptations make birds more prone to open fractures with exposed bone parts losing vascularization. As a result of this exposure, fractures are colonized by different microorganisms, including different types of bacteria, both aerobic and anaerobic, causing osteomyelitis in many cases. For this reason, antibiotic treatment is common. However, carrying out antibiotic treatment without carrying out a previous antibiogram may contribute to increased resistance against antibiotics, especially in migratory wild birds. In this paper, bacterial counts regarding fracture type, bacterial identification and antibiotic resistance have been analysed in wild birds from wildlife rehabilitation centres in Spain. The results obtained showed that open fractures had higher bacterial counts (CFU/mL) than closed ones. Bacteria in family Enterobacteriaceae, identified were Escherichia spp., Enterobacter spp., Shigella spp., Hafnia alvei, Proteus mirabilis, Leclercia adecarboxylata and Pantoea agglomerans. Other bacteria present in wild birds’ fractures were Aeromonas spp., Enterococcus spp. Bacillus wiedmannii and Staphylococcus sciuri. All species found presented resistance to at least one of the antibiotics used. Wild birds can be implicated in the introduction, maintenance and global spreading of antibiotic resistant bacteria and represent an emerging public health concern. Results obtained in this paper support the idea that it is necessary to take this fact into account before antibiotic administration to wild animals, since it could increase the number of bacteria resistant to antibiotics.     

南水北调中线工程水质监测站点布设研究

科学合理布设水质监测站点是加强南水北调中线工程对突发水污染事件监控,保障水质安全的重要手段。制定水质监测站点的布设方案受到监测效率与布设成本的约束,同时,监测仪器精度、污染物衰减特性的不确定性等问题也对布设方案产生影响。以中线工程京石段为研究对象,基于一维水质模型,以突发水污染事件漏报率最低、发现时间最短以及监测站点布设成本最小为目标函数,构建水质监测站点布设多目标优化模型对布设方案进行优化,同时结合监测仪器精度对目标函数的影响确定了最优布设方案,在此基础上,分析了污染物衰减特性对最优布设方案的影响。研究结果可为中线工程合理布设水质监测站点提供建议。     

Potential impact of weedy Brassicaceae species on oil and meal quality of oilseed rape (canola) in Australia

Brassicaceae weeds are a widespread problem in Australian oilseed rape crops. The weeds not only compete for resources during crop growth, but also have the potential to reduce both oil and meal quality of the harvested crop. This study investigated oil and meal quality of weedy species from the Brassicaceae family that were collected throughout cropping regions of Australia. Eighty‐nine lines from 19 species were grown and evaluated in the same environment for their potential to contaminate Australian oilseed rape seed lots. Seed and flowering characteristics of each species were also examined. The glucosinolate concentration of most of the weedy species was greater than 100 μmol g^?1 of oil‐free meal, well above the threshold for meeting oilseed rape quality. Erucic acid content of 18 of the 19 weedy species also exceeded the oilseed rape quality standard of less than 2% erucic acid. This study highlights the potential of the weedy species to reduce the quality of Australian oilseed rape crops.     

铬胁迫对黄豆生理特性的FTIR研究和铬积累特征

为了对Cr~(6+)污染土壤修复提供参考依据。通过水培,研究了不同Cr~(6+)水平对黄豆幼苗根、茎、叶的傅立叶红外光谱(FTIR)图谱变化,同时测定Cr~(6+)的亚细胞分布和Cr~(6+)富集的影响。结果表明:幼苗对Cr~(6+)的积累能力与处理浓度呈正比。其叶片富集的Cr~(6+)在细胞壁分布最多(37.14%~63.52%),线粒体和叶绿体最少(12%)。根组织在1064、1404、1635、2924、3417 cm-1等处峰高呈先升后降的变化趋势,可能是在低Cr~(6+)浓度,通过增加糖类和氨基酸等有机物含量来响应Cr~(6+)胁迫;茎组织在1072、1427、1643、2924、3387 cm-1等处峰高呈现不显著变化趋势;叶组织在1110、1396、1651、2924、3433 cm-1等处峰高先降后升,表明叶中一些富含O-H小分子有机物质(碳水化合物)被运输到根部螯合Cr~(6+)来响应低Cr~(6+)胁迫。研究结果表明,黄豆幼苗能有效地吸收土壤中的Cr~(6+),在Cr~(6+)污染土壤植物修复技术领域,拥有潜在的利用价值。     

Temporal variation of total and DTPA-extractable heavy metal contents as influenced by sewage sludge and perlite in a calcareous soil

Continuous application of sewage sludge (SS) as a source of organic matter, may increase available heavy metals (HMs) up to their critical levels. As a consequence their uptake by plants, risks of accumulation in food chain and groundwater pollution increases. To evaluate the effects of perlite and SS on total content and available fraction of iron (Fe), manganese (Mn), lead (Pb), copper (Cu), nickel (Ni), cadmium (Cd) and zinc (Zn) over 45 and 90 days a completely randomized pot experiment was conducted. Treatments consisted of SS (0, 2 and 4%) and combined SS and perlite levels (1:1, 1.5:0.5 and 0.5:1.5% SS:perlite). Mean available Fe, Ni, Cd, Mn and Zn fractions decreased over time by 7–27%, whereas, total contents did not change. Available HMs in SS-treated soils increased by 0.5–25%; whereas, only total Zn, Cu and Pb concentrations increased with SS application (although concentrations fall in the range of critical levels). The lowest (1.6 fold) and highest (22.1 fold) increases obtained for available Cu and Zn, respectively. Perlite could mitigate the adverse effect of high rate application of SS on amplification of HMs extractability. Therefore, their concomitant applications can be suggested considering the perlite durability and its positive effects on soil physical properties.     

Chemometric Methods to Predict of Pb in Urban Soil from Port Pirie,South Australia,using Spectrally Active of Soil Carbon

A total of 73 soil samples were initially analyzed for lead (Pb) concentration as an indicator of the environment impact of smelter activity in the Port Pirie, South Australia. Chemometric techniques were used to assess the ability of near-infrared (NIR) reflectance spectroscopy to predict soil Pb using spectrally active soil characteristics such as soil carbon (C). The result indicated a strong linear relationship between log-transformed data of soil Pb and spectral reflectance in the range between 500 and 612 nm with R² = 0.54 and a low root-mean-square error (RMSE_v = 0.38) for the validation mode with an acceptable ratio of performance to deviation and ratio of error range (1.6 and 7.7, respectively). This study suggested that NIR spectroscopy based on auxiliary spectrally active components is a rapid and noninvasive assessment technique and has the ability to determine Pb contamination in urban soil to be useful in environmental health risk assessment.     

不同混施钝化剂对水稻吸收累积Cd的影响

将石灰、赤泥和高岭土按不同比例混合(施用总量为4500kg hm-2)施加于Cd污染稻田土壤,根据混合比例不同设置CK(常规种植)、T1(1∶7∶4)、T2(3∶5∶4)、T3(4∶4∶4)和T4(6∶2∶4)共5个处理,探究不同混施钝化剂对水稻吸收累积Cd的影响。结果表明:4种混施处理能够显著降低土壤有效态Cd含量,较CK相比依次降低了28.0%、40.9%、43.4%和57.4%。4种混施处理能够不同程度地降低水稻各部位对Cd的吸收累积,籽粒的Cd含量依次降低47.1%、49.2%、55.5%和81.6%,T2、T3和T4处理水稻籽粒中Cd含量达到了食品安全国家标准(G B27622017,Cd≤0.2mg kg-1)。土壤有效态Cd含量与水稻根、茎、叶和籽粒中Cd含量的Pearson相关系数分别为0.826、0.709、0.778和0.532,均达到显著相关。不同处理根系富集系数依次为5.03、1.83、2.22、1.32和0.90,钝化处理显著降低了水稻根系对Cd的富集能力。各处理水稻产量以及籽粒K、Mg元素含量没有显著差异,T1到T4处理Ca元素含量依次增加。综合分析,T4处理对于降低土壤中有效态Cd含量以及水稻籽粒中Cd含量效果最佳,且没有降低水稻产量和与稻米品质密切相关的K、Mg和Ca元素含量。