沉积物中多环芳烃和有机氯农药定量分析的质量保证和质量控制

以美国ＥＰＡ为方法为基础,进行了沉积物中多环芳烃和有机氯农药分析的质量保证和质量控制实验,采用回收率指示物控制回收率,用内标法定量。结果表明多环芳烃的指示物回收率为５０．６７－９７．３３％,目标化合物的回收率为５８．６７－９６．３３％,方法检测限为３．３０－９．２６μｇ．ｋｇ＾－１。     

西南部分地区麻疯树种子油的理化性质及脂肪酸组成分析

从西南6个地区采集了麻疯树种子并分析比较了其生物学性状和种子油的理化性质及脂肪酸组成.所有样品的百粒重范围为41.80~71.39g,出仁率60.02%~81.43%,种仁含油率51.76%~57.93%,种子含油率31.07%~47.17%,不饱和脂肪酸含量74.89%~79.68%.其中永胜产麻疯树的种子品质最好,其出仁率为81.43%,种仁含油率57.93%,种子含油率47.17%,不饱和脂肪酸含量79.68%.攀枝花和宁南产麻疯树的种子品质次之.双柏和罗甸麻疯树的种子油酸值为0.81,在所有样品(0.81~9.46)中最低.对麻疯树种子及种子油性质的相关数据进行方差分析,结果表明,产地不同,麻疯树种子的生物学性质、种子油理化性质和脂肪酸组成都有一些差异.图2表3参18     

湖南烟区烤烟锌含量与土壤有效锌的分布特点及关系分析

采用野外调查和室内分析相结合的方法,研究了湖南烟区烤烟锌含量与土壤有效锌含量的分布特点及关系。结果表明,(1)湖南烟叶锌含量总体适宜,平均为(36.30±14.05)mg·kg-1,变幅为10.50~100.50mg·kg-1;调查区域内有92.58%的烟叶样本锌含量落在20.00~80.00mg·kg-1区间内;不同等级烟叶锌含量的规律是:B2F>C3F>X2F。(2)湖南植烟土壤有效锌含量适中,平均为(2.27±3.74)mg·kg-1,变幅为0.13~62.59mg·kg-1,变异系数高达155.09%;有22.41%的土壤样本在不同程度上缺锌(≤1.00mg·kg-1),有7.36%的样本的有效锌含量超过4.00mg·kg-1,满足优质烟生长的土壤样本达到70.23%;不同土壤类型有效锌含量的变化规律是:鸭屎泥>黄泥田>黄灰土>黄壤土。(3)烟叶锌含量与土壤有效锌含量呈极显著正相关,相关系数为0.312;与土壤有效铜、有效铁和有效硫均呈极显著正相关,与土壤pH值、有效钾和水溶性氯均呈显著负相关。(4)在土壤有效锌含量分组后,不同等级烟叶锌含量均随着土壤有效锌含量的增加,而呈现先增加后下降的趋势,且各等级烟叶锌含量在组间差异达到5%的显著水平。     

夏季渭河西安段溶解性有机质(DOM)的特征、分布及来源分析

通过紫外吸收光谱,三维荧光光谱结合平行因子分析(EEMs-PARAFAC)方法及主成分分析(PCA),研究了夏季渭河西安段水体中的溶解性有机质(DOM)的组成、来源,及其与水质指标的相关性.在研究区域共检出2种类别5个不同的DOM组分,分别为类腐殖质荧光组分C1、C2、C3、C5和1个类蛋白类荧光组分C4,5个组分具有...     

广州市农业环境污染及其对策

慨述了广州市农业环境污染状况，指出工业“三废”和城镇生活污水等外源污染是造成农业环境污染的主要因素，养殖业废水直接排放和频繁使用农用化学品也对农业环境造成一定程度的污染。提出了建立健全农业环境监控管理体系、推行农业生产许可制度、加强面源污染控制、推广无公害农产品生产技术、加大农业生态环境保护执法力度等污染控制对策。     

磷细菌筛选及其对苗期玉米生长的影响

从潮土、水稻土、砂姜黑土、石灰土上植物根际土壤和根中分离了86株磷细菌,通过NBRIP液体摇瓶培养3 d,培养液水溶磷质量浓度为4.2～387.3 mg.L^-1,水溶磷质量浓度与培养液pH呈显著负相关（r^2=0.621 6）。筛选出3株磷细菌进行玉米盆栽试验,结果表明,1株磷细菌处理的玉米干物质量和吸磷量与对照（处理4）相比无显著差异,2株磷细菌处理的玉米干物质量和吸磷量与对照相比有明显增加,干物质量增加了19.6%～37.5%,吸磷量增加了22.7%～40.2%,其中编号为HCW115解磷菌株的效果相当于施用无机磷（P）10 mg.kg^-1处理。     

Using hydrochemical signatures to characterize the long-period evolution of groundwater information in the Dagu River Basin,China

• The long-period groundwater evolution was identified by hydrochemical signatures. • The dominant processes in the groundwater evolution were verified. • Groundwater quality in the coastal areas was susceptible to deterioration due to SI. • Groundwater contamination arose from fertilizer, livestock manure & domestic sewage. The evolution of hydrochemical compositions influenced by long-period interactions between groundwater and the geo-environment is a fundamental issue for exploring groundwater quality and vulnerability. This study systematically investigated the hydrochemical processes and anthropogenic interference occurring in the river basin by bivariate plots, Gibbs diagrams, saturation index, and the major ions ratios. Apparent changes in groundwater hydrochemistry have been observed in the study area, illustrating the origins of major ions are affected by various internal and external factors. Results highlighted that TDS varied from freshwater to brackish water, ranging between 187.90 and 2294.81 mg/L. Ca²⁺ and HCO₃⁻ are the dominant ions in the studied samples. The results gained by Gibbs diagrams, bivariate plots, saturation index, and the major ions ratios demonstrated that minerals dissolution/precipitation, cation exchange, and human inputs play crucial roles in the unconfined aquifers. Moreover, the overuse of nitrogen fertilizer, livestock manure, and industrial/domestic sewage led to nitrate and nitrite contamination and brought significant challenges to the surrounding hydrogeo-environment. The present study could make an unambiguous identification of natural processes and anthropogenic interventions influencing groundwater hydrochemistry’s long-period evolution and create a preliminary strategy for groundwater resources management.     

Characteristics of plankton Hg bioaccumulations based on a global data set and the implications for aquatic systems with aggravating nutrient imbalance

• Hg bioaccumulation by phytoplankton varies among aquatic ecosystems. • Active Hg uptake may exist for the phytoplankton in aquatic ecosystems. • Impacts of nutrient imbalance on food chain Hg transfer should be addressed. The bioaccumulation of mercury (Hg) in aquatic ecosystem poses a potential health risk to human being and aquatic organism. Bioaccumulations by plankton represent a crucial process of Hg transfer from water to aquatic food chain. However, the current understanding of major factors affecting Hg accumulation by plankton is inadequate. In this study, a data set of 89 aquatic ecosystems worldwide, including inland water, nearshore water and open sea, was established. Key factors influencing plankton Hg bioaccumulation (i.e., plankton species, cell sizes and biomasses) were discussed. The results indicated that total Hg (THg) and methylmercury (MeHg) concentrations in plankton in inland waters were significantly higher than those in nearshore waters and open seas. Bioaccumulation factors for the logarithm of THg and MeHg of phytoplankton were 2.4–6.0 and 2.6–6.7 L/kg, respectively, in all aquatic ecosystems. They could be further biomagnified by a factor of 2.1–15.1 and 5.3–28.2 from phytoplankton to zooplankton. Higher MeHg concentrations were observed with the increases of cell size for both phyto- and zooplankton. A contrasting trend was observed between the plankton biomasses and BAF_MeHg, with a positive relationship for zooplankton and a negative relationship for phytoplankton. Plankton physiologic traits impose constraints on the rates of nutrients and contaminants obtaining process from water. Nowadays, many aquatic ecosystems are facing rapid shifts in nutrient compositions. We suggested that these potential influences on the growth and composition of plankton should be incorporated in future aquatic Hg modeling and ecological risk assessments.     

Modeling porosity reductions caused by mineral fouling in continuous-wall permeable reactive barriers

A study was conducted to assess key factors to include when modeling porosity reductions caused by mineral fouling in permeable reactive barriers (PRBs) containing granular zero valent iron. The public domain codes MODFLOW and RT3D were used and a geochemical algorithm was developed for RT3D to simulate geochemical reactions occurring in PRBs. Results of simulations conducted with the model show that the largest porosity reductions occur between the entrance and mid-plane of the PRB as a result of precipitation of carbonate minerals and that smaller porosity reductions occur between the mid-plane and exit face due to precipitation of ferrous hydroxide. These findings are consistent with field and laboratory observations, as well as modeling predictions made by others. Parametric studies were conducted to identify the most important variables to include in a model evaluating porosity reduction. These studies showed that three minerals (CaCO3, FeCO3, and Fe(OH)2 (am)) account for more than 99% of the porosity reductions that were predicted. The porosity reduction is sensitive to influent concentrations of HCO3-, Ca2+, CO3(2-), and dissolved oxygen, the anaerobic iron corrosion rate, and the rates of CaCO3 and FeCO3 formation. The predictions also show that porosity reductions in PRBs can be spatially variable and mineral forming ions penetrate deeper into the PRB as a result of flow heterogeneities, which reflects the balance between the rate of mass transport and geochemical reaction rates. Level of aquifer heterogeneity and the contrast in hydraulic conductivity between the aquifer and PRB are the most important hydraulic variables affecting porosity reduction. Spatial continuity of aquifer hydraulic conductivity is less significant.     

琼脂碳源生物反硝化去除水源水中硝酸盐

针对受硝酸盐污染的水源水,以琼脂为反硝化细菌的碳源和微生物载体,通过生物反硝化作用脱除水源水中的硝酸盐,并利用曝气生物滤池(BAF)去除琼脂反应器出水中残留的少量CODMn和NO2--N等污染物。实验结果表明,水源水自然接种的条件下,可以顺利启动琼脂反应器;在温度为25℃左右,琼脂反应器在进水NO3--N约25 mg/L、水力停留时间1.5 h时,能获得70%的硝酸盐氮去除率;曝气生物滤池在水力停留时间0.5 h、气水比2.8时,可控制最终出水的CODMn和NO2--N分别在5.0 mg/L和0.10 mg/L以下;琼脂反应器的脱氮效果与温度、进水NO3--N浓度及水力停留时间等有关。研究指出,琼脂反应器与曝气生物滤池构成的组合系统能较好地脱除水源水中的硝酸盐并且能控制最终出水水质,不会导致二次污染,从而获得合格的饮用水源水。