China-PEARL和PRZM-GW模型潍坊市场景农药地下水风险评估研究

农药地下水暴露模型China-PEARL已开始在我国农药地下水风险评估中应用。本文利用China-PEARL潍坊市场景数据,为PRZM-GW构建了潍坊市场景。在潍坊市场景下,利用2个模型计算了56种农药在5种作物上共计145种施用方式下的预测环境浓度（PEC）值,利用商值法（RQ）进行风险评估。结果显示有8种农药共13种施用方式在潍坊市场景下存在不可接受的地下水风险。其中,2个模型均显示有不可接受风险的农药是多菌灵和氟磺胺草醚。2个模型PEC值比较结果显示,PRZM-GW的农药风险评估趋势与China-PEARL一致性高,从而验证了China-PEARL的可信性。模型PEC值影响因素分析显示,土壤有机碳分配系数（Koc）对2个模型输出影响最大,可将Koc〉400L·kg^-1作为判断某种农药预测浓度〈0.1μg·L^-1经验性指标。2个模型的PEC值和土壤好氧半衰期的对数呈线性关系,当土壤好氧半衰期〉10d时,模型的PEC值随土壤好氧半衰期的增大而迅速增高。水解半衰期为PRZM-GW模型输入项,决定了PRZM-GW模型模拟的农药浓度随年变化趋势。水中溶解度是China-PEARL的输入项,但对模型PEC值影响很小。     

基于产品生命周期的环境管理

原料从开采、加工、再加工等生产过程到形成最终产品,又经过贮运、销售、消费、使用等过程,直至报废、回收和最终处置等生命周期带来不少环境问题。通过基于产品生命周期的设计、生产、流通、服役、退役等不同阶段,分别采用绿色设计、环境友好生产、生态标志认证、减少流通环节、绿色采购与消费、延伸生产者责任、建立回收与处置体系等环境管理模式,以减少甚至避免环境污染,为企业、管理部门、公众对产品全过程的环境管理提供系统认识和综合管理。     

Constructed Wetland Treatment of Nitrates: Removal Effectiveness and Cost Efficiency

A constructed wetland (CW) was strategically placed to treat nitrates in groundwater as part of a watershed‐based farmer engagement process. Using stream water quality data collected before and after installation, this CW was found to reduce stream concentrations of nitrogen from nitrate (NO₃‐N) during the growing season by about 0.14 mg/l at mean streamflow, a 17% reduction. Based upon realistic ecological and economic assumptions, about 80 kg of NO₃‐N were removed annually by the CW at a cost of around US$30/kg. This per unit cost is at the low range of small wastewater treatment plant costs for nitrates, but higher than the costs of reduced fertilizer application.     

Application of a Modified Health Belief Model to the Pro‐Environmental Behavior of Private Well Water Testing

A social cognition model of health behavior, the health belief model, was applied to the pro‐environmental behavior of private well water testing. Conceptualizing environmental behaviors as health behaviors may provide new insight into pro‐environmental behavior change. A groundwater education program was provided to K‐12 children throughout New England. Both child participants and their parents completed surveys pertaining to private well water behavior. Results indicate that perceived barriers and socioeconomic status significantly influenced past well water testing of parent participants. Perceived barriers included: participants' concern related to the cost of treating their water, and how a well water problem would influence their property value. Parent participants also indicated that they would perform future well water testing if they received a reminder cue to action that might include: getting a discount or reminder in the mail, if a well testing program was available, and state or local requirement. Our findings reinforce the need for continued private well water research and parallels to additional environmental behaviors.     

Water Balances of Two Piedmont Headwater Catchments: Implications for Regional Hydrologic Landscape Classification

In the Piedmont of North Carolina, a traditionally water‐rich region, reservoirs that serve over 1 million people are under increasing pressure due to naturally occurring droughts and increasing land development. Innovative development approaches aim to maintain hydrologic conditions of the undisturbed landscape, but are based on insufficient target information. This study uses the hydrologic landscape concept to evaluate reference hydrology in small headwater catchments surrounding Falls Lake, a reservoir serving Raleigh and the greater Triangle area. Researchers collected one year of detailed data on water balance components, including precipitation, evapotranspiration, streamflow, and shallow subsurface storage from two headwater catchments representative of two hydrologic landscapes defined by differences in soils and topographic characteristics. The two catchments are similar in size and lie within the same physiographic region, and during the study period they showed similar water balances of 26‐30% Q, ?4 to 5% ΔS, 59‐65% evapotranspiration, and 9‐10% G. However, the steeper, more elevated catchment exhibited perennial streamflow and nongrowing season runoff ratios (Q/P) of 33%, whereas the flat, low‐lying stream was drier during the growing season and exhibited Q/P ratios of 52% during the nongrowing season. A hydrologic landscape defined by topography and soil characteristics helps characterize local‐scale reference hydrology and may contribute to better land management decisions.     

西南岩溶山区分散供水水污染特征

西南岩溶山区分散供水在一定程度上缓解了人畜饮水矛盾,但分散供水水质都存在不同程度的污染。通过对西南岩溶山区三种主要的分散供水模式供水水质的调查、监测与分析,认为分散供水水质的污染由两部分组成：水源水污染与供水水污染;水源水污染源属于面状污染,供水水污染属于点状污染。分散供水水污染类型主要有生物型污染（肉眼可见物以及不可见微生物）、物理型污染（色度、浊度）以及化学型污染（pH值呈碱性以及生活垃圾、粪便引起的离子浓度异常）,并以生物污染为主。污染途径主要有降雨过程污染、径流过程污染（地表、地下径流以及引水过程）和储蓄利用过程污染。最后,针对岩溶山区分散供水特点,给出了相应的水处理方法。     

渤海某油田注水井筛管失效测试及原因分析

目的 对注水井防砂筛管失效进行原因分析,解决注水井防砂问题。方法 针对渤海某油田注水井的防砂筛管失效问题,打捞失效筛管,并对破损区取样,通过损伤部位宏观和微观形貌、关键区域EDS能谱成分测量及室内模拟测试与计算分析等手段,综合分析各部位的损伤特征及规律。结果 宏观和微观形貌分析结果表明,损伤区域呈现明显的冲蚀损坏特征,测试与计算结果得出损伤速率为1.299 mm/a,寿命预测约为0.35 a(4.2个月),与现场实际比较吻合。结论 地层砂在筛管外堆积,造成筛管堵塞,形成高压差,高速注入水冲击筛管外的堆积砂,形成含砂流体在筛管外表面附近区域的紊流,对筛管局部反向冲击形成含砂流体冲刷腐蚀,从而造成局部冲蚀破坏穿孔。为有效解决冲蚀损伤问题,建议后续采取砾石充填防砂方式。     

南水北调典型受水区浅层地下水水化学特征及成因

以邯郸黑龙港平原作为典型受水区,运用描述性统计、Piper图、离子比例分析、饱和指数和氯碱指数等方法,开展浅层地下水水化学变化特征及其成因分析研究.结果表明:南水北调中线工程通水后浅层地下水总体上由咸水向微咸水转化,浅层地下水水质的改善与水位恢复存在密切的相关性;6月和12月浅层地下水主要水化学类型分别是Na-SO₄-Cl型和Na-HCO₃型.蒸发岩(岩盐、石膏和芒硝)和碳酸盐岩矿物(方解石和白云石)的溶解/沉淀作用控制着浅层地下水主要离子浓度的变化.大部分区域发生了正向阳离子交换作用,而地下水位降落漏斗区或钠离子浓度相对富集区域则主要发生了反向离子交换作用.工业和生活污水排放、农业化肥使用可能在一定程度上造成部分浅层地下水的污染.研究结果对南水北调中线受水区地下水资源可持续开发利用和环境保护具有重要意义.     

Pickering乳化强化地下水三氯乙烯NAPL修复

合成了4种不同长径比的SiO₂颗粒调控水/NAPL界面,考察所形成的Pickering乳化效果和稳定性,结果表明：长径比（L/D）为2.3的SiO₂颗粒分散的Pickering乳液液滴尺寸均匀,直径约10 μm,且10d内保持稳定,乳化指数高达63%.流变测试进一步证实所形成的Pickering乳化具有低剪切应变下乳液稳定的特性,利于地下水的原位修复技术的实施.同时考察胶体颗粒浓度,水中离子强度以及水/NAPL比例对Pickering乳化效果和稳定性的影响,为Pickering乳化技术在实际地下水修复应用提供理论基础.通过对比Pickering乳化和未乳化条件下NAPL溶解和氧化降解动力学过程,发现Pickering乳化通过增大两相间界面积显著提高NAPL的溶解速率,进而实现NAPL相污染物降解速率的提高.     

渭河流域关中段地下水硝态氮来源解析

为定性及定量识别地下水中氮的污染来源及迁移转化特征,本文在水化学分析的基础上结合氮氧稳定同位素技术及SIAR模型对渭河流域关中段地下水补给来源、地下水中氮污染特征进行了判断.结果表明,渭河流域关中段地下水的主要水化学类型为HCO₃-Ca+Mg型,地下水由降水快速入渗补给和地表水入渗补给.地下水氮污染以硝态氮形式为主,在所采集的34个地下水水样中,硝态氮含量的变化范围为0.154~36.717mg/L,平均含量为6.17mg/L,其中硝态氮含量超过Ⅲ类地下水标准的采样点共有2个,超标率为5.9%.氮循环的主导作用为硝化作用.地下水δ¹⁵N-NO₃^-含量的变化范围为+6.08‰~+16.42‰,δ¹⁵O-NO₃^-含量的变化范围为+9.38‰~+12.514‰,硝态氮污染主要受到人类活动的影响,土壤有机氮、粪便及污废水和大气沉降是地下水硝态氮的主要贡献者,平均贡献率分别为44.65%、40.03%和15.32%.