Characteristics of oxytetracycline sorption and potential bioavailability in soils with various physical-chemical properties

Veterinary antibiotics are widely used for disease treatment, prevention and animal growth promoting. Frequent detection of veterinary antibiotics in environments, caused by land application of untreated or even treated antibiotics-containing animal wastes, has posed the growing concern of their adverse effect on natural ecosystems. Oxytetracycline (OTC) is one of the most widely-used veterinary antibiotics in livestock industry. OTC present as a cation, zwitterions, or net negatively charged ion in soils complicates predicting its sorption characteristics and potential bioavailability and toxicity. This study was to identify soil properties influencing OTC sorption and its subsequent bioavailability in five soils with various physical-chemical properties. A solution used to determine bioavailable analytes in soils and sediments, 1 M MgCl₂ (pH 8.5), was chosen to desorb the potentially bioavailable fraction of OTC sorbed onto soils. Our results demonstrated that soils with higher illite content and permanent cation exchange capacity have higher OTC sorption capacity, but increase the availability of sorbed OTC indicated by higher release of sorbed OTC from soils into aqueous phase in 1 M MgCl₂ (pH 8.5). Reversely, soil organic matter (SOM), clay, kaolinite, variable cation exchange capacity, DCB-Fe and -Al have lower OTC sorption capacity, but decrease the release of sorbed OTC from soils into 1 M MgCl₂. These findings indicate that SOM and clay greatly influence OTC adsorption and potential availability. This study contributes significantly to our understanding of the potential bioavailability of sorbed OTC and the effects of soil properties on OTC sorption behaviors in soils.     

Polybrominated diphenyl ethers in soils of the modern Yellow River Delta, China: occurrence, distribution and inventory

The Yellow River is the second largest river in China. In this study, the levels of polybrominated diphenyl ethers (PBDEs) in the modern Yellow River Delta (mYRD) were firstly reported. Twenty PBDE congeners in soil/sediment samples from mYRD were measured. The total PBDE concentrations ranged from non-detectable to 18 257 ng kg⁻¹ with a mean value of 836 ng kg⁻¹. BDE-209 was the dominant congener, accounting for ∼86.1-99.5% of the total PBDEs. The congener profiles of PBDEs with higher abundances of BDE-153 and BDE-183 were similar to those in sediment of the Bohai Sea, indicating that they shared similar sources. The concentrations and congener patterns varied among different regions. Higher levels of PBDEs were found in the middle area (MA), and more complicated congener compositions were also observed in the MA, whereas lower levels of PBDEs were found in the modern course (MC) and the old course (OC). Much more PBDEs were detected in the top layer (TL) soil where more congeners were also held compared to lower soil layers, implying that more PBDEs were emitted into this area in recent years/decades. Organic matter controlled the PBDE distribution in the soil. Soil in this area might be a source of BDE209 for the Bohai Sea.     

Remediation of polycyclic aromatic hydrocarbon (PAH) contaminated soil through composting with fresh organic wastes

Introduction  

Composting may enhance bioremediation of PAH-contaminated soils by providing organic substrates that stimulate the growth of potential microbial degraders. However, the influence of added organic matter (OM) together with the microbial activities on the dissipation of PAHs has not yet been fully assessed.     

电解锰渣二次提取锰和氨氮的研究

锰渣处理是电解锰行业的一个重大环境问题.为了实现锰渣无害化处理和资源化利用,用蒸馏水和阳极液作提取剂,对从锰渣中二次提取锰和氨氮进行了研究.考察了液固比、提取剂种类、提取时间、提取温度、超声波作用对锰、氨氮提取效果的影响,且对提取前后的锰渣成分进行了检测与表征.研究结果表明:阳极液对锰的提取效果明显优于蒸馏水,而蒸馏水...     

基于电阻率的硫酸污染水泥土检测方法的探讨

电阻率法作为一种简单有效的测试方法,已在岩土工程检测中得到了一定程度的应用.通过室内试验模拟了水泥土试块受不同浓度硫酸溶液污染的反应,采用电阻率法研究了孔隙水电阻率、水泥土电阻率、结构因子与溶液浓度和龄期之间的关系.结果表明,孔隙水和水泥土电阻率随溶液浓度增大而减小、随龄期的增大而增大,结构因子随着溶液浓度和龄期的增加而增加,它们之间具有较高的相关性.这充分说明,电阻率法可应用于硫酸污染水泥土的检测和评价.     

火炸药企业重大事故隐患危险性评估的计算机自学习实现

通过对火炸药工厂重大事故隐患危险性评估方法的分析,以计算机自学习的基本结构为主线,详细探讨了以机械学习策略完成该评估程序中对新危险品源自学习的过程。对此过程中知识表示等几个应注意的问题进行了描述     

一种解毒健脾中药驱除有毒重金属的机理研究

在３８．５±１℃,硝酸钾维持离子强度为０．１的条件下,用ｐＨ电位滴定法测定了一种解毒健脾中药有效成分与铅、镉、汞等离子形成的各各配合物的表观稳定常数,得到了在不同ｐＨ条件下该中该药与金属离子混合体系中各配合物组分的物种分布图,发现在与人体生理ｐＨ相近的条件下,该中药与铅、镉、汞等离子有良好的结合能力,其排除体内有毒重金属的效果远好于传统的ＥＤＴＡ－Ｚｎ盐,并且对体内必需微量元素Ｚｎ的存在不会产生明     

超滤处理豆腐废水阻力的研究

采用中空纤维聚砜超滤膜,对处理豆腐废水过程中膜阻力的分布进行了研究。通过测定不同条件下超滤的通透量,计算出超滤过程中各种阻力及其所占的比例。试验结果表明预处理及超滤条件不同,其过滤阻力构成也不同。预处理愈完善,其浓差极化阻力愈低,总阻力也越小。     

载银TiO2半导体催化剂降解染料水溶液的研究

以新型载银ＴｉＯ２为催化剂,采用高压汞灯为光源对染料水溶液进行光催化降解。实验结果表明：采用ＴｉＯ２催化剂使直接耐酸大红（３５ｍｇ／Ｌ）、直接耐晒翠蓝（５０ｍｇ／Ｌ）和直接黑（５０ｍｇ／Ｌ）染料溶液脱至无色的时间分别为３５ｍｉｎ、６０ｍｉｎ及６０ｍｉｎ,而采用载银ＴｉＯ２催化剂,上述染料溶液脱至无色的时间分别为２０ｍｉｎ、３０ｍｉｎ及２０ｍｉｎ。探讨了ｐＨ、光强、催化剂用量及灼烧温度等对催化降解的     

利用环己酮下脚料合成盐酸缓蚀剂

以环己酮下脚料,甲醛和脂肪胺为原料,合成了一种新的盐酸缓蚀剂,用失重法测定了合成物在盐酸中对２０＃碳钢的缓蚀性能,研究了温度和浓度对缓蚀性能的影响,结果表明,在６０℃、２０％盐酸溶液中,添加０．２％合成缓蚀剂,缓蚀效率在９９％以上。