Spatio-temporal variations of selected pesticide residues in the Kurose River in Higashi-Hiroshima city,Japan

ABSTRACT

This study investigated spatio-temporal variations of selected pesticide residues in the Kurose River in Higashi-Hiroshima city (Hiroshima Prefecture), Japan. Water samples were collected from the river at seven sites every month for 1 year (March 2016 to February 2017). Pesticide residues were extracted from the samples by a solid phase extraction using Sep Pack C₁₈ cartridges. Once extracted, the samples were analyzed for cyanazine, simetryn, fenarimol, isoprothiolane, and diazinon using a reversed-phase high-performance liquid chromatography ultraviolet visible (HPLC-UV Vis) system. The limits of detection were 3.60, 4.10, 2.80, 6.50, and 7.30 ng L^-1 for cyanazine, simetryn, fenarimol, isoprothiolane, and diazinon, respectively. Good recovery rates (88%–102%), and mean percent relative standard deviation range (1.00%–5.70%) (n = 6) were obtained with a spiking at 0.20 µg L^-1. The maximum concentrations of 282, 391, 60, 1086, and 1194 ng L^-1 were obtained for cyanazine, simetryn, isoprothiolane, fenarimol, and diazinon, respectively. Cyanazine was the most frequently detected pesticide (64% of the samples, n = 84), followed by simetryn (58%), and then diazinon (57%). The highest and lowest pesticide concentrations were measured during the periods May–June, and January–February, respectively. Principal component analysis revealed three principal components in which the pesticides were linked to dissolved organic matter and total suspended solids. The major water quality parameters (electrical conductivity, pH, Na⁺, K⁺, Mg²⁺, Ca²⁺, NH₄⁺, NO₃^?, Cl^?, SO₄^2?, NO₂^?, and temperature) showed no clear trends for these pesticides. The presence of simetryn and isoprothiolane was largely attributed to rice paddy farms, whereas diazinon was associated mostly with vegetable farms and orchards. The diazinon and isoprothiolane patterns were consistent with their use of controlling insects and fungi in the prefecture. The maximum diazinon concentration detected was higher than the human safe level specified by the European Union (100 ng L^-1) in Council Directive 98/83/EC. This is of concern because of the bioconcentration potential of these residues in fish and other marine animals consumed by humans.     

青萍生长特征及其对受污染河水的修复效果

以浮萍优势品种青萍（Lemna minor）为研究对象,开展受污染河水修复。分析了青萍在不同营养盐浓度条件下的生长特征,探讨了青萍对受污染河水的修复效果。在表面积为0.0095 m2的限制空间条件下,青萍在1、2和5 mg总氮（TN）/L营养液中的生长特征都能较好地服从Logistic生长模型,受制约的临界鲜重（FW）分别为1.20、1.36和1.36 g;青萍对受污染河水中氮磷污染物具有较好的去除效果,氨氮（NH＋4-N）的平均去除率、平均去除量和平均去除速率分别为56.87%、1.22 mg/d和0.0466 mg/（g FW·h）,正磷酸盐（PO3-4-P）的平均去除率、平均去除量和平均去除速率分别为66.95%、0.25 mg/d和0.0088 mg/（g FW·h）。根据相关性分析,进水NH＋4-N和PO3-4-P浓度与其对应去除量之间极显著相关;青萍FW与NH＋4-N去除速率之间显著负相关,但与PO3-4-P去除速率之间不存在显著相关性;NH＋4-N进水浓度与去除速率相关性不显著,但PO3-4-P进水浓度与去除速率显著正相关。     

Effects of wavelength and water quality on photodegradation of N-Nitrosodimethylamine (NDMA)

N-Nitrosodimethylamine (NDMA) is a potent carcinogen that yields a cancer risk of 10⁻⁶ at concentrations as low as 0.7 ng L⁻¹. Tentative guideline values are set at 3 ng L⁻¹ in California, USA; 9 ng L⁻¹ in Ontario, Canada; 40 ng L⁻¹ nationwide in Canada; and 100 ng L⁻¹ by the World Health Organization. NDMA is a great concern in treating reclaimed water as well as drinking water. UV degradation can be considered effective degradation method. A 1-log reduction of NDMA is achieved by 1000 mJ cm⁻² of a 254-nm low pressure (LP) mercury UV lamp. However, a higher degradation efficiency than that provided by LP lamps is desired in practical treatment. In this study, the effects of wavelength and water quality were investigated to achieve higher degradation efficiency. The effects of wavelength were examined by comparing three UV lamps: a 222-nm Kr Cl Excimer UV lamp, a 254-nm LP mercury UV lamp, and a 230- to 270-nm filtered medium pressure (FMP) mercury UV lamp. The 222-nm lamp and FMP lamp achieved 4 times and 2.8 times higher degradation efficiency, respectively, than the conventional 254-nm LP lamp. Effects on water quality were also simulated by using absorption spectrum data of nitrate solutions and process water from a drinking-water treatment plant. In the simulation, the 222-nm lamp was affected by UV-absorbing compounds in the water, whereas the FMP lamp showed more stable degradation efficiency. Appropriate use of these three types of lamps could enhance the efficiency of degradation of NDMA.     

基于演化博弈的流域生态补偿利益冲突分析

资源合理利用与环境保护是维护当今经济平稳、健康、较快发展的重要前提。生态补偿是缓解经济快速发展与环境污染、生态环境破坏之间利益矛盾冲突的重要手段。它是为了制止生态破坏而征收或补偿的费用,所以不同于一般排污费和资源补偿费。本文根据补偿的类型不同,将生态补偿分为资源型生态补偿和环境型生态补偿。本文以流域生态补偿为例,将流域上游政府的策略简化为保护或不保护河流,下游政府针对上游的情况,选择"自主型"或"接受型",运用演化博弈的方法,分析流域生态补偿的特点和结果。结果表明:流域生态补偿需要中央政府的适度干预,而且关键点是保证上游地方政府收益始终最大化;中央政府干预的程度是使上游政府群的收益在保护的情况下比不保护的收益要大,而干预的结果则是使流域上下游的(保护,补偿)策略成为演化博弈的长期稳定均衡。最后本文针对我国现行流域管理体制,为我国流域生态补偿提供了政策建议,以推广我国生态补偿政策。     

基于纳污红线的河流排污权优化分配模型

实行水功能区限制纳污红线的水资源管理制度,在理论和实践中必须要建立河流污染物总量控制管理制度,而实行污染物总量控制,首先要确定河流排污权的初始分配方案。结合我国现行流域水功能区划成果,以水功能区作为排污权初始分配主体开展排污权分配研究,提出由河流环境保护部门确定河流总体排污权,首先通过纵向配置将排污权分配给水功能区,然后通过横向配置将初始排污权分配给排污者的一种纵向加横向分配模式。以资源分配的公平性和效率为管理目标,并以污染物总量控制、浓度控制、企业生产连续性等为约束条件,建立了河流排污权多目标分配优化模型。最后利用多目标演化算法对算例进行了求解,验证了方法的可行性,且此分配方式所获得的环境节余容量最大     

How seasonality affects the flow of estrogens and their conjugates in one of Japan's most populous catchments

A detailed study of the free and conjugated estrogen load discharged by the eight major sewage treatment plants into the Yodo River basin, Japan was carried out. Sampling campaigns were focused on the winter and autumn seasons from 2005 to 2008 and the free estrogens estrone(E1), 17β-estradiol(E2), estriol(E3), 17α-ethynylestradiol(EE2) as well as their conjugated (sulfate and glucuronide) forms. For both sewage effluent and river water E2 and E1 concentrations were greatest during the winter period (December-March). This coincides with the period of lowest rainfall and lowest temperatures in Japan. E1 was the dominant estrogenic component in effluent (means of 10-50 ng/L) followed by E2 (means of 0.5-3 ng/L). The estrogen sulfate conjugates were found intermittently in the 0.5-1.7 ng/L concentration range in the sewage effluents. The greatest estrogen exposure was found to be in the Katsura River tributary which exceeded 1 ng/L E2-equivalents during the winter period.     

沛沿河流域土壤施肥后氮、磷释放规律的模拟研究

为有效控制农业面源污染,改善沛沿河流域水质状况,通过对稻田、林地、果园的土壤分别施用不同化肥后,模拟研究了土壤在受雨水短期浸泡及连续降雨情况下氮、磷的释放规律.结果表明,稻田土壤对氮、磷的释放能力最差,施肥时应以基肥为主;林地、果园土壤的保肥能力均劣于稻田土壤,应采用“少量多次追肥”的方法.尿素与碳铵宜作为基肥施用,而...     

镇江滨江带湿地修复对浮游生物群落结构的影响

在镇江滨江带50 m×50 m的开放性湿地内进行实验,通过构建高位湿地、架设植物浮巢来改善滨江带湿地生境梯度和生境异质性,营造适宜各类士著动植物生长发育的湿地环境,从而达到增强生态系统延展性及增加生物多样性的目的.结果表明,高位湿地的构建、植物浮巢的架设等生态修复措施对提高研究区浮游植物、浮游动物群落的生物多样性有着显...     

北京城市水系水环境模拟及情景分析

城市水系是流域水环境管理中最为脆弱的控制点.针对城市水系水动力条件差、有机污染和富营养化严重的问题,应用QUAL2K模型模拟、预测城市水系水环境的时空变化,并在此基础上探讨北环水系水环境管理和污染防治的合理有效方案.结果显示,经过多次调整后的模型模拟的匹配度达到了0.9135,水温、溶解氧、COD、TN、TP和Chl-...     

古黄河泗阳段流域生态环境保护工程

通过采取治、退、拆、清、修、整、建、养、植等生态修复综合措施、建立古黄河生态保护圈,加强古黄河泗阳段周边环境的生态保护,进一步净化水体环境,增加古黄河泗阳段蓄水量,提高水质的稳定性,使得社会效益、环境效益和经济效益达到最佳统一,实现水资源的持续利用。同时改善古黄河地区的空气环境,实现古黄河泗阳地区的蓝天碧水。