微塑料与铅复合污染对玉米种子萌发与生长的影响

为探明微塑料和重金属复合污染对作物种子萌发与生长的影响,以玉米种子为对象,探究了铅(Pb)和3种微塑料[聚乙烯(PE)、聚丙烯(PP)、聚氯乙烯(PVC)]不同单一及复合浓度暴露对玉米种子萌发及其生长的影响.结果表明,Pb单一暴露对玉米种子发芽的抑制总体上随其浓度的升高而增强;与CK相比,500、 1 000和1 500 mg·L^-1PE暴露显著抑制玉米种子发芽,100 mg·L^-1和300 mg·L^-1暴露影响不显著(第5 d除外);所有PP浓度暴露均显著抑制玉米种子发芽;相比PP和PE,PVC单一暴露对玉米发芽抑制较轻.Pb和3种微塑料复合暴露均显著抑制玉米种子发芽,随着时间的增长,抑制逐渐减弱.玉米种子的发芽指数、发芽势和活力指数均随着Pb及3种微塑料单一暴露浓度升高而减小,且在Pb和PE复合暴露下较CK显著减小,但在Pb和PP、 Pb和PVC复合暴露下均无显著变化;3种微塑料中,PVC对玉米种子活力影响相对最轻.10 mg·L^-1Pb和100 mg·L^-1的3种微塑料单...     

Polypropylene microplastics alter the cadmium adsorption capacity on different soil solid fractions

• PP-MPs reduced the adsorption capacity of the bulk soil for Cd in aqueous medium. • The responses of the POM, OMC and mineral fractions to PP-MPs were different. • PP-MPs reduced the adsorption of POM and OMC fractions to Cd. • PP-MPs increased the adsorption of mineral fraction to Cd. • Effect of MPs on soil may be controlled by proportion of POM, OMC and mineral fractions. Microplastics (MPs) are widely present in a variety of environmental media and have attracted more and more attention worldwide. However, the effect of MPs on the the interaction between heavy metals and soil, especially in soil fraction level, is not well understood. In this study, batch experiments were performed to investigate the adsorption characteristics of Cd in bulk soil and three soil fractions (i.e. particulate organic matter (POM), organic-mineral compounds (OMC), and mineral) with or without polypropylene (PP) MPs. The results showed that the addition of PP-MPs reduced the Cd adsorption capacity of the bulk soil in aqueous solution, and the effects varied with PP-MPs dose and aging degree. Whereas, the responses of the three fractions to PP-MPs were different. In presence of PP-MPs, the POM and OMC fractions showed negative adsorption effects, while the mineral fraction showed positive adsorption. For the bulk soil, POM and OMC fractions, the adsorption isotherm fitted to the Langmuir model better than the Freundlich model, whereas, the Freundlich isotherm model is more fitted for the mineral fraction. Combined with the comprehensive analysis of the partitioning coefficients, XRD and FTIR results, it was found that OMC fraction extremely likely play a leading role in the bulk soil adsorption of Cd in this study. Overall, the effect of MPs on adsorption capacity of the bulk soil for Cd may be determined by the proportion of POM, OMC, and mineral fractions in the soil, but further confirmation is needed.     

我国陆域水体系统表层水中微塑料生态风险评估

针对我国陆域水体系统表层水微塑料（MPs）生态风险问题,通过Science Direct和Web of Science等网站查询关键词microplastics、urban和river等获取相关文献及数据,从2017~2021年的研究,覆盖15个省份33个水体,并基于MPs丰度、聚合物占比和化学危害数据构建了生态风险表征比率（RCR）的评价方法.结果表明,我国自然水体的MPs丰度平均值为（3604.2±5926.4） n ·m^-3,城市水体中MPs丰度平均值为（7722.6±9505.7） n ·m^-3;相应的,自然水体的RCR平均值为22.09±45.2,城市水体RCR平均值为15.67±34.8.因此,根据RCR的值将生态风险程度划分为4个等级.其中,无显著风险（≤1）有17个,占42.5%;低生态风险（1~10）有12个,占30%、中生态风险（10~100）有9个,占22.5%;高生态风险（>100）有2个,占5%.数据分析显示,自然水体的MPs丰度与RCR值（R²=0.875,P<0.01）存在显著的相关性,但在城市水体的MPs丰度与RCR值间不存在显著的相关性.这表明MPs的丰度高并不能说明该地区的生态风险程度高.此外,各地的RCR值与流域面积呈正相关（R²=0.864,P<0.01）,同时,MPs丰度与GDP （R²=0.679,P<0.05）、流域常住人口（R²=0.922,P<0.05）呈显著相关性.这项研究为评估MPs的生态风险提供了基线数据,是陆域水体系统表层水MPs生态风险评价的重要方式.     

厦门湾沙滩沉积物微塑料污染特征

微塑料（MPs）广泛存在于各种环境介质中,目前已经成为全球性环境问题.为了解海湾沙滩沉积物中微塑料的污染特征,揭示微塑料沉积规律及其影响因素,在厦门湾选择了5个典型沙滩,根据潮汐变化,同时在高潮线、中潮线和低潮线分层采集了0~10、10~20和20~30 cm的沉积物柱状样品,研究了沙滩沉积物中微塑料水平与垂直分布特征.结果表明,厦门湾沙滩45个沉积物样品中均检出微塑料,微塑料丰度范围为39~260 n ·kg^-1,平均丰度为（114±26） n ·kg^-1;微塑料形状主要为纤维状、碎片状、颗粒状和泡沫状,其中纤维状占比最大;主要成分为聚对苯二甲酸乙二醇酯（PET）、赛璐芬（cellophane）和聚乙烯（PE）;微塑料的颜色包括透明、蓝色、黄色、黑色和白色等.从统计结果可以看出,微塑料的平均丰度因沙滩位置、潮间带位置和采样深度的不同呈一定的规律,并且波浪、潮汐、岸线形状、风、游客数量和海漂垃圾清洁等自然和人为多种因素均影响沙滩微塑料的丰度和分布.研究成果有助于了解沙滩沉积物中微塑料的污染特征及来源,为微塑料的陆海传输提供依据,对海漂垃圾及岸滩垃圾收集提供数据支撑.     

胚胎绒毛膜对微塑料颗粒与镉联合作用的影响

利用胚胎发育技术和代谢组学技术,以100nm（n-PS）和70~250μm（μ-PS）两种粒径的聚苯乙烯（Polystyrene,PS）颗粒为研究对象,从微塑料与胚胎绒毛膜相互作用这个角度,探讨了不同粒径微塑料颗粒和镉（Cd）对斑马鱼胚胎发育联合毒性的差异.结果表明,Cd单独暴露、及其与n-PS和μ-PS联合暴露中,胚胎绒毛膜上Cd的蓄积量分别为3.82,13.66,11.35mg/g,而这三个暴露组中Cd在胚胎体内的含量分别为0.24,0.16,0.20mg/g.n-PS更为显著地增加了Cd在胚胎绒毛膜上的蓄积、降低了Cd在胚胎中的含量（P<0.01）.但是μ-PS却更大程度地降低了Cd的胚胎发育毒性（P=0.006）.代谢组学的数据证实,由于PS颗粒对胚胎绒毛膜堵塞作用,纳米PS颗粒能够促进Cd作用下胚胎的氧化压力和细胞的能量需求.因此,胚胎绒毛膜在微塑料对水生生物早期发育的毒性研究中起着重要作用.本研究能够为微塑料在环境中的生物可利用性和效应研究提供一些新的思考方向.     

Microplastic contamination in Great Lakes fish

Freshwater ecosystems, generally adjacent to human population and more contaminated relative to adjacent marine ecosystems, are vulnerable to microplastic contamination. We sampled 7 species of fish from Lake Ontario and Lake Superior and assessed their gastrointestinal (GI) tracts to quantify ingested microplastics and other anthropogenic particles. A subset of the microparticles were chemically analyzed to confirm polymer types and anthropogenic origins. We documented the highest concentration of microplastics and other anthropogenic microparticles ever reported in bony fish. We found 12,442 anthropogenic microparticles across 212 fish (8 species) from nearshore Lake Ontario, 943 across 50 fish (1 species) from Humber River, and 3094 across 119 fish (7 species) from Lake Superior. Fish from Lake Ontario had the greatest mean abundance of anthropogenic microparticles in their GI tracts (59 particles/fish [SD 104]), with up to 915 microparticles in a single fish. Fish from Lake Superior contained a mean [SD] of 26 [74] particles/fish, and fish from Humber River contained 19 [14] particles/fish. Most particles were microfibers. Overall, ≥90% of particles were anthropogenic, of which 35-59% were microplastics. Polyethylene (24%), polyethylene terephthalate (20%), and polypropylene (18%) were the most common microplastics. Ingestion of anthropogenic particles was significantly different among species within Lake Ontario (p < 0.05), and the abundance of anthropogenic particles increased as fish length increased in Lake Ontario (ρ = 0.62). Although we cannot extrapolate the concentration of microplastics in the water and sediments of these fish, the relatively high abundance of microplastics in the GI tracts of fish suggests environmental exposure may be above threshold concentrations for risk.     

乌鲁木齐南部大气及降尘中微塑料的形貌特征

采用体视显微镜、傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和能量色散光谱（EDS）等对乌鲁木齐南部大气总悬浮颗粒物（TSP）及降尘样品中微塑料的颜色、成分及形貌等特征进行分析.结果表明，TSP和降尘中存在纤维、碎片和薄膜等多种形状的微塑料，且TSP和降尘中的微塑料分别以纤维状（81.8%和86.2%）和碎片状（56.3%~68.4%）为主；通过FTIR鉴定出TSP和降尘中的塑料成分主要是聚乙烯，聚丙烯和聚苯乙烯；SEM发现纤维状微塑料表面较为光滑，有少量的裂痕，上面分布少量碎屑；碎片状微塑料边缘卷曲破碎，形状不规则，破损程度高，表面黏附大量的颗粒物；EDS分析表明微塑料中以C和O元素为主，还包含Si、Na、Zn等元素.结果可为进一步了解乌鲁木齐大气微塑料的污染情况提供基础数据支撑.