Photocatalytic removal of heavy metal ions and antibiotics in agricultural wastewater:A review

In recent years,the treatment of agricultural wastewater has been an important aspect of environmental protection.The purpose of photocatalytic technology is to degrade pollutants by utilizing solar light energy to stimulate the migration of photocarriers to the surface of photocatalysts and occur reduction-oxidation reaction with pollutants in agricultural wastewater.Photocatalytic technology has the characteristics of high efficiency,sustainability,low-energy and free secondary pollution.It is an environmental and economical method to recover water quality that only needs sunlight.In this paper,the mechanism and research progress of photocatalytic removal of heavy metal ions and antibiotics from agricultural water pollution were reviewed by combining photocatalytic degradation process with agricultural treatment technology.The mechanism of influencing factors of photocatalytic degradation efficiency was discussed in detail and corresponding strategies were proposed,which has certain reference value for the development of photocatalytic degradation.

Water Quality and Heavy Metal Monitoring in Water, Sediments, and Tissues of the African Catfish Clarias gariepinus (Burchell, 1822) from the River Nile, Egypt

Water quality of the river Nile and trace elements of the water, sediments and fish tissues were investigated in the current work. Eighteen different sampling points were selected along the whole course of the River Nile from its spring at Aswan to its estuaries at Rosetta and Damietta. Higher mean value of conductivity, alkalinity, chemical oxygen demand (COD), total organic carbon (TOC), ammonia (NH3), nitrate (NO3), total solid (TS), sulphate (SO4), chloride (Cl), orthophosphate were recorded in the water of Damietta and Rosetta branches comparing to other sites. Also trace metals in the water, sediments and tissues of Clarias gariepinus increased significantly (P Fe > Cu > Pb > Mn > Cr> Cd > Hg. In the gill tissues theses metals were accumulated in the following order Fe > Zn > Mn > Pb > Cr > Cu > Cd> Hg. The low accumulation of metals in muscle may be due to lack of binding affinity of these metals with the proteins of muscle. This is particularly important because muscles contribute the greatest mass of the flesh that is consumed as food.

Water Quality and Some Heavy Metals in Water and Sediments of Euphrates River, Iraq

Water samples, sediments from three stations in Euphrates River, lraq were analyzed quantitatively for some physical and chemical characters and six heavy metals （Co, Cu, Fe, Mn, Ni and Pb） using flam atomic absorption spectrophotpmeter in period Sept. 2009-Oct. 2010. The physical and chemical characters included temperature, pH, water flow, salinity, dissolved oxygen, BOD5, alkalinity total hardness, calcium and nutrients （nitrite, nitrate reactive phosphate and silicate）. The results showed variation in water flow 0.05-0.40 m/sec., according to the values of salinity 0.40%-0.60% values of the BOD5 were ranged between 0.2-4.3 mg/L. The mean concentration of the heavy metals （Pb, Ni, Mn, Co, Cu and Fe） of the dissolved phase in water were 0.13 μg/L, 0.021 μg/L, 0.31 μg/L, 4.29 μg/L, 7.78 μg/L, 6.46 μg/L and 79.04 μg/L, respectively, while their concentration in the particulate phase were 0.59 μg/g, 0.06 μg/g, 0.42 μg/g, 50.06 μg/g, 6.61 μg/g, 7.17 vg/g and 149.42 μg/g dry weight, respectively. Also the mean concentrations of heavy metals in sediment （exchangeable phase） were 0.51 vg/g,0.18 vg/g, 0.08 μg/g, 61.39 μg/g, 5.40 μg/g, 14.06 vg/g and 130.05 μg/g dry weight respectively, and 0.40 μg/g, 0.17 μg/g, 0.10 μg/g, 63.01 μg/g, 4.64 μg/g, 18.44 μg/g and 126.26 μg/g D.W. respectively in residual phase of sediment.

The Improvement of the Quality of Irrigation Water Contaminated with Heavy Metals in the Borg El Arab, Egypt

The aim of this study is to estimate the effects of the accumulation of harmful heavy metals in the irrigation water resulting from the proximity of the various activities of various water: sewage, artesian wells and industrial activities, particularly Borg El Arab Industrial area and take Nile water l Control (Bahig canal). The concentrations of these heavy metals in samples drawn from different distances from the source of irrigation in summer 2011 that contain the highest concentrations, followed by the winter of 2012. These results have shown that the amount of heavy metals in the samples at a distance of 50 meters is more than quantity of 5000 m by a 30 to 35 twice in water for irrigation, also the amount of heavy metals in the samples at a distance of 50 meters has values less than the permissible limits and disappeares completely at a distance of 5000 meters and that for different sources.

Status of persistent organic pollutants and heavy metals in surface water of Arctic region

Trace pollutants in the surface water of the Arctic region have been analyzed by the capillary gas chro-matography with the micro-electron capture detector (GC- mECD), the gas chromatography-mass spectrometry (GC- MS) and the inductively coupled plasmas-mass spectrometry (ICP-MS). Compared with previously reported studies, concentrations of OCPs in these regions are much lower than those in the last decades. The ratio of a-/g-HCH indicates the different pesticide composition between these two regions and is the potential marker for the source of the OCPs. Many other OCPs with different residue patterns have also been found for the first time in the two regions. No heavy metal contaminant was found in the investigation regions.

ANALYSIS SOLUTION OF ONE-DIMENSIONAL MATHEMATICAL MODEL ABOUT HEAVY METAL TRANSPORT FOR RIVER WATER

Water quality model about heavy metal under general initial and boundary conditions was studied. The model includes adsorption of suspended sediment, adsorption of bed load, advective diffusion of flow water, which affect the concentration of heavy metal in river water. Laplace transforms method was adopted, its integral equation of the concentration of diluting heavy metal and solid heavy metal was given. The characteristic of the model under constant solution was discussed. Using this model the prediction of mercury (Hg) ions concentration distribution along a section of Yellow River in Lanzhou, China was performed. The computational value is approximately equal to the measured value.

Development and Application of Water Quality Index (WQI) for the Evaluation of the Physico-Chemical Quality of Groundwater in Gold Mining Areas of Southeastern Senegal

Water is the most essential requirement for life. It provides a variety of purposes such as a source of water supply for drinking, domestic and industrial use, irrigated agriculture, livestock, and mining activities. Evaluating the status of water quality from traditional approaches does not guarantee the whole overview of the water quality situation. Therefore, developing a tool that can convert multiple parameters data into information that is understandable by both technical and non-technical personnel is vital. In this context, the purpose of this paper was to develop, calculate, and apply a water quality index for assessing the suitability (for drinking purposes) of groundwater in the gold mining areas in south-eastern Senegal. The development of this index based on WHO water quality guidelines followed the five standards steps i.e., parameters selection, sub-index formation, parameters weighting and sub-index aggregation and evaluation. Finally, the WQI summarized twelve key water quality parameters into 05 simple terms (excellent, good, medium, poor, and very poor) which is more relevant for reporting to managers and the public in a consistent manner. Thus, it was observed in the study area, that the water quality indexes in artisanal and industrial mining areas are either poor or very poor while in the reference stations (where there are no mining activities) WQI are either good or excellent. This situation was attributed to the effects of mining activities in such zones which contribute to the pollution of groundwater with heavy metals, nitrates, and suspended solids.

Equations and their physical interpretation in numerical modeling of heavy metals in fluvial rivers

Based on the previous work on the transport-transformation of heavy metal pollutants in fluvial rivers, this paper presented the formulation of a two-dimensional model to describe heavy metal transport-transformation in fluvial rivers by considering basic principles of environmental chemistry, hydraulics, mechanics of sediment transport and recent developments along with three very simplified test cases. The model consists of water flow governing equations, sediment transport governing equations, transport-transformation equation of heavy metal pollutants, and convection-diffusion equations of adsorption-desorption kinetics of particulate heavy metal concentrations on suspended load, bed load and bed sediment. The heavy metal transport-transformation equation is basically a mass balance equation, which demonstrates how sediment transport affects transport-transformation of heavy metals in fluvial rivers. The convection-diffusion equations of adsorption-desorption kinetics of heavy metals, being an extension of batch reactor experimental results and a major advancement of the previous work, take both physical transport, i.e. convection and diffusion and chemical reactions, i.e. adsorption-desorption into account. Effects of sediment transport on heavy metal transport-transformation were clarified through three examples. Specifically, the transport-transformation of heavy metals in a steady, uniform and equilibrium sediment-laden flow was calculated by applying this model, and results were shown to be rational. Both theoretical analysis and numerical simulation indicated that the transport-transformation of heavy metals in sediment-laden flows with clay-enriched riverbed possesses not only the generality of common tracer pollutants, but also characteristics of transport-transformation induced by sediment motion. Future work will be conducted to present validation/application of the model with available data.

Preliminary Study on Formulating Water Quality Standards for Estuaries of China

In China,the water quality standards in operation include the Environmental Quality Standard for Surface Water（GB3838-2002）and Water Quality Standards for Seawater（GB3097-1997）.However,these two standards are currently not suitable for the estuarial zones of China because of the unique properties of water environment in estuaries.We proposed preliminarily a basic idea and technical workflow in formulating water quality standards for the estuaries of China based on analyzing the water environment properties of estuaries comprehensively and comparing various parameters and their standard values mentioned in these two standards above.Issues pertinent to the formulation of the water quality standards for estuaries,e.g.nutrient,heavy metals and persistent organic pollutants（POPs）,are highly concerned.The objective of this paper is to provide technical support for the formulation of scientific water quality standards and the assessment of water quality of the estuaries of China.

Water quality, agriculture and food safety in China:Current situation, trends, interdependencies, and management

Water quality in China is becoming a severe challenge for agriculture and food safety, and it might also impact health of population via agriculture and food. Thus, it is causing widespread concern. Based on extensive literatures review and data mining, current situation of water pollution in China and its effects on food safety were analyzed. The 2nd National Water Resource Survey in China show that the surface water all over the country was under slight pollution and about 60% of groundwater is polluted. Drinking water quality is basically guaranteed in urban area but it is worrisome in rural areas. In addition, China is the largest consumer of fertilizer and pesticide in the world and the amounts of application still show increasing trends. Fertilizers and pesticides are the most important sources of pollution, which affect human health as persistent organic pollutants and environmental endocrine disruptors. Eutrophication of surface water and nitrate pollution of groundwater are serious threats to drinking water safety. Sewage irrigation is becoming a pollution source to China＇s water and land because of lacking of effective regulations. Although, with the advance in technology and management level, control of nitrogen and phosphorus emissions and reducing water pollution is still a major challenge for China.

Impact Assessment of Poultry Discharge on the Physico-Chemical and Microbiological Water Quality of Olosuru Stream in Ikire, Southwestern Nigeria

This study investigated the impact assessment of poultry wastes discharge from a nearby poultry farm on the physico-chemical and microbiological water quality of Olosuru Stream, Ikire, Southwestern Nigeria. Five sampling stations (designated A, B, C, D and E) each located at 250 m interval along the course of the stream were selected for the study. The physico-chemical parameters in the water body vary in concentration along spatial, monthly and seasonal variation of Olosuru stream. The patterns of spatial distribution of physico-chemical parameters measured for the stream were generally similar except for calcium and hardness which showed significant difference for the five stations. The overall mean values of most of the parameters investigated;pH (7.45 ± 0.24), conductivity (628.69 ± 255.95 μs/cm), TDS (377.3 ± 153.55 mg/L), sulphate (10.89 ± 2.37 mg/L), BOD5 (3.19 ± 2.35 mg/L), cadmium, arsenic, manganese, total heterotrophic bacteria count (15,080.67 ± 20,250.67 cfu/ml), total coliform bacteria count (3226 ± 8426.70 cfu/ml) and total heterotrophic fungi count (2567.4 ± 7652.12 cfu/ml) were negatively impacted by poultry wastes dumping into the stream. The concentrations of most parameters exceeded recommended permissible limits of the Nigerian Standard for Drinking Water and World Health Organization for freshwater quality. The water source is therefore deemed not potable and poses hazards to public health if consumed without treatment. There is urgent need for improved management strategies of this water resource for continued sustainability.

Assessment of Surface Water Quality of Bétaré-Oya Gold Mining Area (East-Cameroon)

To assess the water quality in the locality of Bétaré-Oya affected by an intensive artisanal and semi mechanized mining activities, 71 samples were collected from sixteen points during the 2015-2016 hydrological year. These points include: three in Lom river which is the main stream of the study area, five in Mari river which is one of the left bank tributaries of the Lom, in Bétaré-Oya and eight in the left and the right bank of Mari. Different physicochemical parameters such as pH, electrical conductivity (EC), alkalinity, turbidity, total suspended solids (TSS), cyanide (CN-), major elements and heavy metals (Pb, Zn, Cd, Fe, Cu, As, Mn and Cr) were analyzed. Water Quality Indices (WQI), Heavy metal Pollution Index (HPI), sodium adsorption ratio (SAR) and percent sodium (Na%) were also computed to evaluate the suitability of water for drinking and irrigation. The results showed that the surface water from Bétaré-Oya was acidic to basic (5.40 < pH < 8.84), weakly mineralized (11.60 < EC < 122.10 μS/cm) with a high concentration of TSS (2 < TSS < 8996.00 mg/L) and turbidity (1.22 to 4758.00 NTU). The WQI scores show excellently to unsuitable quality in almost all the sampling sites. The water quality is found to be most deteriorated in Lom river and in the downstream of Mari river where an extensive mining activity is carried out, with the high WQI value of 5137.40. Based on heavy metal pollution index, the mean value was 1195.36 and thus under the critical pollution index. We thus notice a serious physical degradation by organic and mineral suspended particles as well as chemical degradation by heavy metals. This results from mining activities in the Lom river and its main tributaries such as the Mari river in the upstream part of the Sanaga basin. According to the percentage of sodium and SAR, these waters can be used for irrigation purposes in almost all types of soils.

典型水污染事故应急处置实用技术探究

当前水污染事故频发多发态势仍未改变,且突发水污染事故处置有预案、缺技术、少装备的问题依然突出。为满足我国水污染事故应急处置需求,综合考虑应急处置技术的去除、稳定性、设备化、机动化、可操作性和适应性等关键因素,重点探讨了水体藻华、重金属和有机物以及水面油类等污染的实用处置技术,优选出移动式藻华高效打捞脱水一体化处置船、化学絮凝耦合超磁分离技术、集约式一体化快速生化污水处理技术、异相催化氧化等高效处置技术,研究成果可为今后突发水污染事故应急处置提供有效支撑。

广西防城港海域表层海水重金属和富营养化特征分析与评价

海水重金属和营养盐的研究对于了解海洋生态系统平衡、评估海洋环境质量、制定保护策略等方面具有重要意义。为研究防城港海域表层海水水体质量,于2021年9月在防城港海域开展调查,分析海水中的溶解氧(dissolved oxygen,DO)、化学需氧量(chemical oxygen demand,COD)、溶解无机氮(dissolved inorganic nitrogen,DIN)、溶解无机磷(dissolved inorganic phosphorus,DIP)及5种重金属(Cu、Pb、Cd、Zn、As)含量,采用单因子指数、水质综合污染指数、有机污染指数和富营养化指数对海水水体质量进行评价。结果显示:除DIN和DIP外,防城港海域表层海水中其他因子均优于二类海水水质标准;单因子评价表明超标因子主要为DIP和DIN,超标率分别为70%和98%;水质综合污染指数法评价表明整个海域均处于轻度及以上污染;重金属风险熵评价结果表明防城港海域主要风险元素为Cu、Cd和Zn;富营养化和有机污染指数表明防城港海域均处于有机污染状态,且有55%区域处于富营养化状态,多集中在企沙半岛南部海域及防城港航道。综合分析表明:DIN和DIP主要受海水养殖业和沿岸污水排放的影响;5种重金属主要来源为海洋运输、海水养殖业及工业废水排放、混合输入源,3种来源相对贡献率分别为18%、8%和74%。研究成果可为防城港海域可持续发展、海洋环境保护和治理提供科学依据。

宿州市埇桥区乡镇水厂重金属含量与水质评价

为探究宿州市埇桥区各乡镇自来水厂供水端重金属含量状况,于2021年7—8月对24个乡镇自来水厂进行水样采集,测定了水中砷(As)、镉(Cd)、铬(Cr)、铜(Cu)、铁(Fe)、锰(Mn)、镍(Ni)、铅(Pb)和锌(Zn)的质量浓度,并利用单因子指数法和内梅罗综合污染指数法对各水厂重金属污染水平进行评价。结果表明:重金属的平均质量浓度从大到小依次为:Mn>Zn>Fe>Cu>Cr>As>Ni>Pb>Cd;与《生活饮用水卫生标准》(GB 5749—2022)相比,Mn的超标率最高,为4.17%;其他8种重金属质量浓度均低于相应的标准限值;单因子污染指数(P_(i))平均值从大到小排序为:Mn(0.248)>As(0.063)>Pb(0.041)>Cr(0.028)>Ni(0.023)>Fe(0.020)>Zn(0.010)>Cd(0.005)>Cu(0.002);从综合污染指数(P_(n))看,仅桃沟水厂达到轻度污染,其他水厂均在安全范围内;从空间分布上看,P_(n)和Mn的单因子污染指数的高值中心区主要分布在桃沟和朱仙庄水厂附近。Mn为研究区水厂的优控污染重金属。研究结果可为埇桥区水厂重金属污染防控与优化水处理工艺提供依据。

水质型缺水地区地下水重金属污染风险评价——以嘉兴市为例

以典型水质型缺水城市嘉兴市作为研究区,采集29个地下水点位的水样,检测Fe、Mn、Cu、As、Pb、Hg、Cd、Cr的浓度以及pH,采用内梅罗指数法和潜在生态风险指数法评价重金属污染程度,基于地统计分析和数理统计方法分析重金属空间分布特征和来源,并引用风险评估模型量化该污染给居民带来的健康风险。结果表明:①研究区地下水的Fe、Mn、As、Pb含量均值超出Ⅲ类标准的限值,超标率为Fe(86.2%)>Mn(75.9%)>As(62.1%)>Pb(20.7%),其余4种元素未超出Ⅲ类标准。②Fe、Mn、Cd的来源相似或迁移转化路径相近,As含量高的地下水呈弱碱性。③研究区的综合潜在生态风险指数为69.27,综合生态危害程度介于轻微—中等之间。④研究区内93.1%的地下水健康风险总值高于成人最大可接受值,海宁市和海盐县的南部地区健康风险总值最高。研究成果可为水质型缺水地区开发利用地下水,以及重金属污染与风险管控提供数据支撑和理论依据。

离子色谱技术在水环境检测中的应用思考

随着工业化和城市化进程的加快,水污染问题日益严峻,对人类健康和生态环境构成了巨大威胁,所以需要对水环境进行监测。离子色谱技术作为一种高效、灵敏的分析方法,在水环境质量监测中显示出不可替代的作用。本文综合探讨了离子色谱技术的基本原理,并深入分析了其在水环境检测中的广泛应用,如常规阴阳离子、有机污染物、重金属的检测等。同时,文章也详细讨论了离子色谱技术的优势。离子色谱技术在实际应用中也存在着一些挑战和问题,例如高昂的设备与耗材成本、部分离子的检测效果不理想以及样品前处理步骤的复杂性等。针对这些问题,本研究提出了一系列改进措施,旨在进一步提升离子色谱技术在水环境监测中的效能和准确性。

区域海湾水质污染检测及生态危害研究

近年来海湾生境退化现象较为严重,造成这种现象的主要原因是人类活动和海岸侵蚀,其中,海洋开发活动、海上污染和陆源污染都会影响海湾水质。当海湾水质受到污染时会造成严重的生态污染,破坏了生态平衡。为了提高海湾水质,恢复海湾生态功能,提出区域海湾水质污染检测及生态危害研究。将山东省日照市作为研究区域,检测区域海湾内总磷、总氮等营养盐指标的含量分布及变化情况,更准确地了解海湾的污染状况;采用营养状况指数法分析上述营养盐指标造成的生态危害;结合潜在风险指数法评价重金属元素对海湾水质造成的生态危害,为后续的水质治理提供了有力的数据参考。根据此次研究结果,有助于为相关区域海湾的水质改善和生态恢复提供有效支持。

基于改进主成分分析法的水环境中重金属污染流域水质生态评价方法研究

为了准确掌握水环境中的重金属污染情况,提高水质生态防治效果,提出了基于改进主成分分析法的水环境中重金属污染流域水质生态评价方法研究。选取研究污染流域水质区域,收集4个区域地表水,测定金属元素含量,通过四类分析与评价法,实现对水环境中重金属污染状况及潜在危害的生态评价,得出评价的B区域和C区域水质综合重金属污染较高,铁元素在四个区域均在第一主成分,是污染程度最高的,整体生态评价为及格。评价结果表明所提方法可以对水环境中重金属污染状况进行精确的评价,辅助保护人民身体健康与生态环境。

基于电化学信号调控优化重金属络合废水处理工艺

[目的]针对重金属络合废水处理过程中存在的难以实时监测与控制的困境,提出了以电化学信号为指示因子的工艺参数优化调控策略。[方法]以模拟废水和实际印刷线路板(PCB)重金属络合废水为研究对象,探究废水处理中氧化还原电位(ORP)、电导率(EC)、p H等电化学信号与处理过程之间的联系,建立水质预测模型。[结果]电化学信号与物质浓度之间存在明显的线性关系,可基于此选择多重线性逐步回归法来建立水质预测模型。芬顿氧化工艺处理实际重金属络合废水实验的结果表明,在H_(2)O_(2)浓度为10mmol/L时ORP达到峰值,COD(化学需氧量)去除率高达75.3%。所建立的芬顿氧化工艺和碱沉工艺水质预测模型的决定系数(R^(2))分别为0.806和0.912。[结论]本研究所建立基于电化学信号的重金属络合废水优化调控策略对实际废水处理具有一定的指导意义。