Distribution and chemical speciation of dissolved inorganic arsenic in the Yellow Sea and East China Sea

Distribution and chemical speciation of dissolved inorganic arsenic were examined in Yellow Sea and East China Sea. Results demonstrated that： （1） both As（Ⅲ） and As（Ⅴ） were detected, with As（V） dominated at 40% stations of surface water and 51% stations of bottom water; （2） influenced by the exchange of fresh and sea water, the type of surface sediment and the transport of various water masses, large values in surface water were observed along the coastal region and in the same latitude of Changjiang River Estuary and Hangzhou Bay, and in bottom water found in the southern area where the Taiwan Warm Current and Kuroshio Current influenced; （3） As（Ⅲ） behaved non-conservatively in Changjiang River Estuary. Man-derived inputs cause substantial positive deviation from the theoretical dilution. The negative correlation of As（Ⅴ） to salinity in surface water suggested that it behaved conservatively during the transportation along Changjiang River Estuary. While, the occurrence of As（Ⅴ） up to the linear fit in bottom water indicated the eventual transfer from dissolved phase to particulate phase, which was impossible to be determined without the knowledge of arsenic level and speciation in suspended particulate matter. Further study is needed on the arsenic source/sink relationships based on the distribution profiles.

Distribution of Dissolved Inorganic Arsenic and Its Seasonal Variations in the Coastal Area of the East China Sea

Water samples were collected in the coastal area of the Changjiang Estuary on four cruises from August 2002 to May 2003. The seasonal variations of dissolved inorganic arsenic （DIAs） distributions were analyzed. The results showed that the distributions of DIAs were mainly influenced by Water （KSSW）. The concentration of the total dissolved the terrestrial input and the intrusion of the Kuroshio Subsurface inorganic arsenic （TDIAs） decreased consecutively from winter to summer, while it increased in autumn. The distributions of TDIAs showed some relationships with salinity and suspended particulate matter （SPM）. The relationships between DIAs speciation （including arsenite [ As（ Ⅲ ） ] and arsenate [ As（ Ⅴ ） ]）, biological activity and the availabilities of the phosphate were investigated in the study area for the cruise August 2002. The ratio of As （Ⅲ）/TDIAs increased with the decrease of phosphate concentrations. In the bottom water, the As（ Ⅲ ）/TDIAs ratio decreased with the increasing of N/P. The concentration of TDIAs decreased 28.7% approximately after the occurrence of harmful algal blooms （HAB） because of the uptake of arsenate by algae. Further study is needed about the arsenic source/sink relationships in their vertical or horizontal profiles and the uptake mechanism during the occurrence of harmful algal blooms.

Synthesis of a Novel Imidazole Ionic Liquid Modified Mesoporous Silica SBA15 for Selective Separation and Determination of Inorganic Arsenic in Rice

A novel 1-methylimidazole ionic liquid modified SBA15 mesoporous silica(1-MIIL@SBA15) was synthesized and applied to selective separation of inorganic arsenic(iAs) in rice by dispersive solid phase extraction(DSPE), followed by hydride generation-atomic fluorescence spectrometric(HG-AFS) quantification. The prepared sorbent was characterized by FTIR, FESEM, BET and Zeta potential. Key parameters of adsorption and desorption in DSPE were optimized using standard reference material 1568 b rice flour. Under optimal conditions, the limit of detection was 8.776 ng/kg, relative standard deviation was ≤2.0%, and recoveries of iAs were in the 92.3～94.4% range. This method was successfully applied to the determination of iAs in rice. Under acidic condition, the electrostatic interaction between the positively charged 1-MIIL@SBA15 and anionic iAs played an important role in selective iAs separation, rendering this method suitable for iAs analysis.

Physiological traits of rice seedlings in response to inorganic arsenic

The aim of our study was to better understand the different responses of rice seedling to different species of inorganic arsenic As203 （As（Ill）） and Na2HAsO4 （As（V））. Our results indicate that the biomass of rice seedling decreased as arsenic concentration increased, with the decrease being more significant at higher arsenic concentrations. In addition, the analysis of superoxide dimutase （SOD）, peroxidase （POD）, and catalase （CAT） in rice roots and leaves showed that the activity of these three enzymes significantly decreased in rice tissues, especially in rice roots, as arsenic concentration was increased,. Further, the uptake and utilization efficiencies of N, P, and K were found to decrease as arsenic concentration was increased. However, the uptake and utilization efficiencies of P and K were mainly affected by As（IlI）, whereas those of N were mainly affected by As（V）. Inductively coupled plasma-mass spectrometry （ICP-MS） was used to assay arsenic accumulation in rice tissues; the results indicate that the arsenic content in rice tissues was enhanced when arsenic concentration was increased, especially in rice roots after arsenic treatment.

Effect of inorganic arsenic in paddy soil on the migration and transformation of selenium species in rice plants

Selenium(Se)in paddy rice is one of the significant sources of human Se nutrition.However,the effect of arsenic(As)pollution in soil on the translocation of Se species in rice plants is unclear.In this research,a pot experiment was designed to examine the effect of the addition of 50 mg As/kg soil as arsenite or arsenate on the migration of Se species from soil to indica Minghui 63 and Luyoumingzhan.The results showed that the antagonism between inorganic As and Se was closely related to the rice cultivar and Se oxidation state in soil.Relative to the standalone selenate treatment,arsenite significantly(p<0.05)decreased the accumulation of selenocystine,selenomethionine and selenate in the roots,stems,sheaths,leaves,brans and kernels of both cultivars by 21.4%-100.0%,40.0%-100.0%,41.0%-100%,5.4%-96.3%,11.3%-100.0% and 26.2%-39.7% respectively,except for selenocystine in the kernels of indica Minghui 63 and selenomethionine in the leaves of indica Minghui 63 and the stems of indica Luyoumingzhan.Arsenate also decreased(p<0.05)the accumulation of selenocystine,selenomethionine and selenate in the roots,stems,brans and kernels of both cultivars by 34.9%-100.0%,30.2%-100.0%,11.3%-100.0% and 5.6%-39.6%respectively,except for selenate in the stems of indica Minghui 63.However,relative to the standalone selenite treatment,arsenite and arsenate decreased(p<0.05)the accumulation of selenocystine,selenomethionine and selenite only in the roots of indica Minghui 63 by 45.5%-100.0%.Our results suggested that arsenite and arsenate had better antagonism toward Se species in selenate-added soil than that in selenite-added soil;moreover,arsenite had a higher inhibiting effect on the accumulation of Se species than arsenate.

Study on biological exposure index of occupational exposure to arsenic and its inorganic compounds

Objective To establish biological exposure index(BEI)of occupational exposure to arsenic and its inorganic compounds through occupational epidemiology and the regression analysis of internal and external exposure of workers.Methods In November 2021,125 workers with occupational exposure to arsenic and its inorganic compounds and 49 office administrators in a non-ferrous metal smelter in Yunnan Province were selected as the exposuregroup and control group,respectively.Air samples from the workplace of the study subjects on weekdays were collected andarsenic concentrations were determined.Urine samples were collected in end-of-work weekend and high performance liquid chromatography-inductively coupled plasma mass spectrometry(HPLC-ICP-MS)was used to detect the levels of trivalent inorganic arsenic(iAs^(3+)),pentavalent inorganic arsenic(iAs^(5+)),monomethyl arsenic(MMA)and dimethyl arsenic(DMA)in urine.

Removal of inorganic arsenic from water using metal organic frameworks

It has been estimated that between 94 million and 220 million people around the world are at risk of consuming drinking water that contain arsenic concentrations higher than 10μg/L(Podgorski and Berg,2020).

Effects of inorganic arsenic on growth and microcystin production of a Microcystis strain isolated from an algal bloom in Dianchi Lake,China

Our previous data have shown that inorganic arsenic concentrations were high in Dianchi Lake,China,where Microcystis blooms often occur.To explore the relationship between arsenic and the growth of Microcystis,the effects of arsenite[As(III)]and arsenate[As(V)]on the growth and toxin production of M.aeruginosa strain FACHB 905 were tested.Results showed that M.aeruginosa FACHB 905 was tolerant to inorganic arsenic and its growth was not inhibited when the concentration of As(III)was below 10-5 mol L-1 or that of As(V)below 10-3 mol L-1.Total microcystin production was stimulated in the presence of 10-7 mol L-1 As(III)and the response of this M.aeruginosa strain to As(III)seemed to be a typical inverted U-shaped hormesis.The content increase of microcystin-LR per cell indicated that the toxicity was enhanced as M.aeruginosa FACHB 905 was exposed to As(V).Considering the relatively high concentration of inorganic arsenic in Dianchi Lake(139μg L-1 in epilimnetic water),the origin of the M.aeruginosa strain,inorganic arsenic favors survival of M.aeruginosa FACHB 905 and may stimulate its microcystin production and cellular toxicity.

A critical review of on-site inorganic arsenic screening methods

Approximately 94 to 220 million people worldwide are at risk of drinking well water containing arsenic > 10 μg/L, the WHO guideline value. To identify non-compliant domestic wells, assess health risks and reduce exposure, accurate and rapid on-site inorganic arsenic screening methods are desirable because all domestic wells worldwide need to be tested.Here, the principles, advantages and limitations of commonly used colorimetry, electrochemistry, and biosensing methods are critically reviewed, with the performance compared with laboratory-based benchmark methods. Most commercial kits are based on the classic Gutzeit reaction. Despite being semi-quantitative, the more recent and more expensive products display improved and acceptable accuracy and shorter testing time (~10 min). Carried out by trained professionals, electrochemical methods are also feasible for on-site analysis, although miniaturization is desirable yet challenging. Biosensing using whole bacterial cells or bio-engineered materials such as aptamers is promising, if incorporated with function specific nanomaterials and biomaterials. Since arsenic is frequently found as arsenite in reducing groundwater and subject to oxidation during sampling, transportation and storage, on-site separation and sample preservation are feasible but the specific methods should be chosen based on sample matrix and tested before use. To eliminate arsenic exposure among hundreds of millions of mostly rural residents worldwide, we call for concerted efforts in research community and regulatory authority to develop accurate, rapid, and affordable tests for on-site screening and monitoring of arsenic in drinking water. Access to affordable testing will benefit people who are socioeconomically disadvantaged.

Multiple transformation pathways of p-arsanilic acid to inorganic arsenic species in water during UV disinfection

p-Arsanilic acid（p-ASA） is widely used in China as livestock and poultry feed additive for promoting animal growth.The use of organoarsenics poses a potential threat to the environment because it is mostly excreted by animals in its original form and can be transformed by UV–Vis light excitation.This work examined the initial rate and efficiency of p-ASA phototransformation under UV-C disinfection lamp.Several factors influencing p-ASA phototransformation,namely,p H,initial concentration,temperature,as well as the presence of Na Cl,NH4＋,and humic acid,were investigated.Quenching experiments and LC–MS were performed to investigate the mechanism of p-ASA phototransformation.Results show that p-ASA was decomposed to inorganic arsenic（including As（Ⅲ） and As（V））and aromatic products by UV-C light through direct photolysis and indirect oxidation.The oxidation efficency of p-ASA by direct photosis was about 32%,and those by HOU and1O2 were 19% and 49%,respectively.Cleavage of the arsenic–benzene bond through direct photolysis,HOU oxidation or1O2 oxidation results in simultaneous formation of inorganic As（Ⅲ）,As（IV）,and As（V）.Inorganic As（Ⅲ） is oxidized to As（IV） and then to As（V） by1O2 or HOU.As（IV） can undergo dismutation or simply react with oxygen to produce As（V） as well.Reactions of the organic moieties of p-ASA produce aniline,aminophenol and azobenzene derivatives as main products.The photoconvertible property of p-ASA implies that UV disinfection of wastewaters from poultry and swine farms containing p-ASA poses a potential threat to the ecosystem,especially agricultural environments.

Determination of Inorganic Arsenic Species by Electrochemical Hydride Generation Atomic Absorption Spectrometry with Selective Electrochemical Reduction

A new direct procedure for the determination of inorganic arsenic species was developed by electrochemical hydride generation atomic absorption spectrometry （EcHG-AAS） with selective electrochemical reduction. The determination of inorganic arsenic species is based on the fact that As（Ⅲ） shows significantly higher absorbance at low electrolytic currents than As（Ⅴ） in 0.3 mol·L^-1 H2SO4. The electrolytic current used for the determination of As（Ⅲ） without considerable interferences of As（Ⅴ） was 0.4 A, whereas the current for the determination of As（Ⅲ） and As（Ⅴ） was 1.2 A. For equal concentrations of As（Ⅲ） and As（Ⅴ） in a sample, the interferences of As（Ⅴ） during the As（Ⅲ） determination were smaller than 5%. The absorbance for As（Ⅴ） could be calculated by subtracting that for As（Ⅲ） measured at 0.4 A from the total absorbance for As（Ⅲ） and As（Ⅴ） measured at 1.2 A, and then the concentration of As（Ⅴ） can be obtained by its calibration curve at 1.2 A. The methodology developed provided the detection limits of 0.3 and 0.6 ng·mL^-1 for As（Ⅲ） and As（Ⅴ）, respectively. The relative standard deviations were of 3.5% for 20 ng·mL^-1 As（Ⅲ） and 3.2% for 20 ng·mL^-1 As（Ⅴ）. The method was successfully applied to determination of soluble inorganic arsenic species in Chinese medicine.

南通地区部分稻谷中铅、镉、铬及无机砷的污染状况分析

目的:测定南通地区部分稻谷中铅、镉、铬及无机砷含量,为安全食用提供依据。方法:采用微波消解处理样品,使用电感耦合等离子体质谱仪(ICP-MS)、液相色谱-原子荧光谱仪进行测定,并根据GB 2762-2017国家标准,采用单因子污染指数法和重金属综合污染指数法进行评价。结论:两个地区40份稻谷普遍存在重金属污染,且铬污染较严重。

东海三门湾主要海产品中典型重金属累积状况

为探究我国东海三门湾主要养殖海产品重金属累积状况,评估当地沿海居民因海产品摄入导致的重金属健康风险,并以此了解海产品中重金属的累积特异性,本研究于2022年10月—12月选取三门湾养殖场进行取样,共取76份样本,包含10个品种,分析样品中总砷、无机砷、总镉、总铅和总汞这几种典型重金属含量,采用单因子污染指数评估这10种海产品受重金属污染的情况,应用目标危害系数及复合危害系数评估当地沿海居民长期食用海产品的健康风险,同时对海产品中无机砷的赋存形态展开讨论。结果表明仅部分虾蛄、梭子蟹中镉含量高于限量值(3.0 mg·kg^(-1)),所有样品中的无机砷、铅和汞的含量均低于限量值。不同种类的海产品对重金属累积存在显著差异,这10种海产品除受到镉不同程度的污染外,另外3种重金属污染均处于正常水平,当地沿海居民长期摄入这10种海产品由重金属引起的健康风险属于低关注级别。每种海产品中的无机砷含量低于总砷含量的5%,且与总砷含量之间表现出弱相关性。本研究可为了解三门湾养殖海产品的重金属污染状况及为评价当地沿海居民食用三门湾养殖海产品引起的重金属暴露风险提供科学依据,同时也可为了解海产品中重金属累积特异性和重金属安全限量值的研究提供基础科学信息。

新疆奎屯地区高砷地下水稳定碳同位素特征及其指示意义

地下水稳定碳同位素可以指示微生物作用下有机质降解过程对砷富集的影响.新疆奎屯地区是中国西北干旱区典型原生高砷水分布区,本研究以地下水为研究对象,奎屯河地表水为对照,通过野外采样,并借助原子荧光、稳定同位素分析等技术手段,对地下水的水化学指标、溶解性无机碳(DIC)、溶解性有机碳(DOC)和碳稳定同位素进行测定与分析.结果表明,研究区73%的地下水为高砷水,平均值为60.60μg·L^(-1),呈还原-弱碱性环境,地表水均为低砷水,呈中性和氧化环境.地下水中优势阴阳离子分别为Cl^(-)和Ca^(2+).地下水DIC受多种来源的共同影响,地表水DIC主要来自碳酸盐岩风化作用的影响.地下水δ^(13)C_(DIC)值的范围为-9.13‰—0.58‰,δ^(13)CDOC值的范围在-21.62‰—-13.79‰之间.地下水中除了微生物作用下有机质降解和碳酸盐岩溶解的影响外,还可能存在产甲烷过程对δ^(13)C_(DIC)值的影响.地下水中δ^(13)C_(DIC)-δ^(13)CDOC差值与ρ(As)、ρ(Fe)均呈显著负相关关系,表明微生物参与了铁氧化物的还原性溶解并促进了As的富集.

氧四环素对稻田土壤铁砷形态转化的影响

为探究稻田土壤中抗生素和As复合污染的相互作用,选取湖南省湘潭市某稻田土壤进行微宇宙培养试验,通过模拟稻田土壤淹水–排干过程,探究氧四环素(OTC)在此过程中对Fe、As氧化还原转化的影响。结果表明,在淹水培养阶段,OTC能够促进土壤铁矿物的还原,使得溶解态、可交换态和吸附态/弱结晶型矿物态Fe(II)含量显著增加,因此在排干阶段能生成更多的·OH自由基,促进溶解态As(III)的氧化。OTC对Fe(III)具有络合和还原作用,能够促进土壤含Fe物质的还原;同时,作为一种广谱的抗菌剂,OTC的选择作用提高了异化铁还原菌的相对丰度,同样能够促进铁矿物的还原溶解。此外在淹水阶段,OTC作用下硫酸盐还原菌相对丰度增加,这使得硫化物结合态As的生成量增加,因而溶解态As含量降低。总体而言,OTC在淹水阶段会促进土壤含Fe物质的还原溶解,但能够通过提高As硫化物的生成量减少As的溶出;在排干阶段则有利于生成更多的·OH,将溶解态As(III)快速氧化,这能够降低水稻吸收和转运As的风险。

电化学技术在粮食重金属快速检测的研究及应用进展

粮食中重金属污染已严重危害到人类的身体健康和生存环境,引起人们广泛关注。电化学检测技术具有灵敏度高、分析速度快、设备简单、检测成本低和便携等优点,有望满足粮食中重金属现场快速检测需求。本文介绍了温和快速前处理技术与丝网印刷电极技术优点,综述了电化学技术在粮食中重金属快速检测的应用现状,即实现了粮食中铅和镉同时快速检测,砷和汞的快速检测存在应用挑战,并重点对新型净化材料和电极修饰技术研究进展与解决粮食中无机砷和汞的快速检测的应用挑战进行了可行性分析与展望。利用磁性纳米吸附材料对粮食样品无机砷、汞进行富集、净化和利用电沉积纳米金修饰丝网印刷电极对实现电化学技术快速检测粮食中无机砷、汞有显著优势。文章为基于电化学技术实现粮食铅、镉、无机砷、汞等主要关注的重金属快速检测提供借鉴。

2020-2023年海南省稻谷中镉和无机砷污染状况评价

目的调查分析海南省大部分市县稻谷镉和无机砷含量,评估其污染状况。方法采集2020-2023年海南省14个市县总共351份稻谷样品,将稻谷脱壳制成糙米粉,采用石墨炉原子吸收光谱法、液相色谱-原子荧光光谱法(liquid chromatography-atomic fluorescence spectroscopy,LC-AFS)分别测量镉、无机砷的含量,采用单因子污染指数和内罗梅综合指数对稻谷中镉、无机砷污染程度进行评价。结果2020-2023年海南省稻谷中镉的检出值均没有超出国家限值,但是在此期间呈现出逐年升高的趋势,镉的平均值由0.046 mg/kg升高至0.092 mg/kg;2020-2023年稻谷样品中无机砷的超标率分别为4.4%、5.2%、4.0%、5.6%,平均值范围为0.15~0.19 mg/kg。稻谷的镉单因子污染指数P98.3等于0.7,处于优良水平,综合污染指数小于0.7,污染程度处于安全水平。结论整体来看海南区内稻谷镉和无机砷污染状况保持在一个合理范围内,但单项无机砷已经出现个别污染的情况,需保持持续关注。

基于HPLC-ICP-MS的水蛭中总砷和无机砷含量及其转移率研究

目的:建立水蛭中总砷及无机砷的分析方法,并研究水蛭煎煮后总砷及无机砷的转移率。方法:采用电感耦合等离子体质谱(ICP-MS)法测定水蛭药材、饮片和标准汤剂总砷量,同时采用人工胃液处理样品,以高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)测定无机砷含量,分析其转移率并进行风险评估。结果:水蛭中的砷主要为无机砷,且三价砷含量高于五价砷,所有批次的水蛭饮片煎煮后总砷及无机砷的转移率均大于60%,风险评估结果显示水蛭中的砷所致安全性风险较低。结论:该方法准确度高,专属性好,揭示水蛭药材在煎煮过程中砷及无机砷的转移规律,可为保障水蛭药材的质量和用药安全提供重要参考依据。

LC-ICP-MS法同时测定富硒大米中有机硒和无机砷

采用液相色谱-电感耦合等离子体质谱(LC-ICP-MS)技术,建立富硒大米中有机硒和无机砷同时检测的方法,用于检测湖北省市售富硒大米中有机硒和无机砷的含量。富硒大米前处理方法选用15 mg蛋白酶E和15 mg蛋白酶K混合提取,色谱条件采用Aglient ZORBAX SB-Aq色谱柱,流动相为20 mmol/L柠檬酸溶液+5 mmol/L己烷磺酸钠溶液+1%甲醇溶液(pH=4.0),1 mL/min流速进样,质谱采用HEHe模式,可在5 min内完全分离出3种有机硒和2种无机砷。3种有机硒和2种无机砷在1~50μg/L范围内具有良好的线性关系,相关系数(R2)均大于0.9990,As(Ⅴ)、As(Ⅲ)、SeCys2、MeSeCys、SeMet的检出限分别为0.10、0.12、0.18、0.15、0.15μg/L,满足检测要求。无机砷的回收率为96.2%~101.3%,相对标准偏差为2.5%~3.9%,有机硒的回收率为72.4%~100.6%,相对标准偏差为2.1%~4.1%。该方法操作简便、快速、灵敏度高,可用于富硒大米中有机硒和无机砷的同时检测。

原子荧光光谱法检测大米无机砷的干扰因素及应对策略

本文阐述大米中无机砷的来源、原子荧光光谱法的原理与优势,分析原子荧光光谱法检测大米无机砷的干扰因素,并提出相应的应对策略,旨在提升检测精度,实现大米中无机砷的准确测定。