Soil microbial communities are essential for the natural attenuation of organic pollutants, yet their ecological responses under long-term contamination remain insufficiently understood. This study examined the bacterial community structure and the abundance of dechlorinating bacteria at a decommissioned pharmaceutical-chemical site in northern Jiangsu Province, China, where the primary pollutants were dichloromethane, 1,2-dichloroethane, and toluene. Eighteen soil samples from the surface (0.2 m) and deep (2.2 m) layers were collected using a Geoprobe-7822DT system and analyzed for physicochemical properties and microbial composition via 16S rRNA gene amplicon sequencing. The results showed that the bacterial community composition was significantly shaped by the soil pH, moisture content, pollutant type, and depth. Dechlorinating bacteria were detected at all sites but exhibited low relative abundance, with higher concentrations in the surface soils. Desulfuromonas, Desulfitobacterium, and Desulfovibrio were the dominant dechlorinators, while Dehalococcoides appeared only in the deep soils. A network analysis revealed positive correlations between the dechlorinators and BTEX-degrading and fermentative taxa, indicating potential cooperative interactions in pollutant degradation. However, the low abundance of dechlorinators suggests that the intrinsic bioremediation capacity is limited. These findings provide new insights into microbial ecology under complex organic pollution, and support the need for integrated remediation strategies that enhance microbial functional potential in legacy-contaminated soils.

Coastal ecosystems have faced escalating environmental degradation in recent years, with eutrophication and nutrient imbalances emerging as critical concerns, particularly in estuarine regions. Understanding the spatiotemporal dynamics of key nutrients, including dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and silicate (SiO3-Si), is essential for effective coastal management. This study examines the spatial and seasonal variations in these nutrients across 36 sampling sites in the Yellow River estuary from 2016 to 2018. Results indicate that DIN was the primary contributor to water quality degradation, with more than 27% of sampling sites exceeding the Class II seawater quality standard in 2018. Nutrient concentrations were notably elevated near the estuary. The eutrophication index (EI) revealed predominantly mild-to-moderate eutrophication levels throughout the study area. The study area exhibited a widespread phosphorus (P) limitation, with 44.4–94.4% of coastal waters experiencing P-restricted eutrophication. The N/P ratio significantly exceeded the Redfield ratio (16), indicating a pronounced nutrient imbalance. Furthermore, SiO3-Si concentrations displayed a declining trend, highlighting the need for balanced nutrient management alongside eutrophication mitigation.

Cadmium (Cd) and polystyrene microplastics (PS) co-contamination always occurs in environment; however, the trophic transfer of Cd and PS is still poorly understood. A hydroponic experiment was conducted to investigate the behavior of Cd in lettuce, together with the root or foliar exposure of different sized PS. Accumulation and chemical form distributions of Cd in leaves were distinguished into young and mature leaves. Subsequently, a 14-day snail feeding experiment was performed. Data showed that Cd accumulation in roots, rather than in leaves, are significantly affected by PS coexistence. However, mature leaves had a higher Cd content than young leaves under the root exposure of PS, while a reverse effect was observed in the foliar exposure. There existed a positive correlation between the food-chain transfer associated Cd (CdFi+Fii+Fiii) in mature leaves and Cd content in snail soft tissue (r = 0.705, p < 0.001), but not in young leaves. Though no bio-amplification of Cd in food chain was observed, an increase of Cd transfer factor (TF) from lettuce to snail was noted in the root exposure of 5 μm PS and the foliar exposure of 0.2 μm PS. Moreover, we observed a highest increase rate of 36.8 % in TF values from lettuce to snail viscera, and a chronic inflammatory response in snail stomach tissue. Therefore, more attentions should be paid to study the ecological risks of heavy metals and microplastics co-contamination in environment.

We investigate the molecular gas properties, especially the dense molecular gas in NGC 1614, using the ALMA (Atacama Large Millimeter/ submillimeter Array) high resolution archival data of 12CO(1-0), 13CO(1-0), 12CO(3-2), 12CO(6-5), HCN(3-2), HCO+(3-2), HCN(4-3), and HCO+(4-3). From the high-resolution integrated intensity maps, a ring structure was detected in the central region (< 1 kpc), and the molecular gas mainly distributes in the central region while there is little gas in the nucleus. The 12CO(1-0) shows an extended structure to the south, north, and southeast, and CO (J⩾3, J is the quantum number of rotational vibration levels), HCN, and HCO+ show that the dense gas mainly concentrated in the central region. Similarly, HCN(4-3)/12CO(1-0) and HCO+(4-3)/12CO(1-0) ratio maps show that the dense molecular gas is mainly concentrated in the ring of the central region. The HCN/HCO+ ratios show that the different regions of the starburst ring might have different excitation conditions. The variations of HCN/HCO+ values in different region of central region may be due to the gas density and temperature. For HCN/HCO+(4-3) ratio map, the higher intensity values (∼0.44 ± 0.04) were obtained in the eastern and western region of the ring, compared to the northern and southern region (∼0.35 ± 0.03). For HCN/HCO+(3-2) ratio map, the higher values (∼0.38 ± 0.04) are distributed at peak location of HCN(3-2) emission, while the lower values (∼0.3 ± 0.03) are distributed at the northwestern and southeastern region of the ring. The mechanism of variations of HCN/HCO+ values in the central region of the galaxy has been discussed in the article.

Soil environmental quality of agricultural land plays a determinate role in the quality of agricultural products, human health, and the safety of the ecosystem. In 2018, China issued the "soil environment quality risk control standard for soil contamination of agriculture land" (GB 15618-2018), which has been essential to soil pollution prevention and the control of agricultural land. In this study, a systematic and comparative analysis of soil environmental standards for the agricultural land of 17 countries or regions was conducted, including the framework, protection objective, derivation method, contaminant elements, analyses methods, and standard values, as well as the impact factors. The results showed that the number of contaminants of GB 15618-2018 was insufficient with the simple consideration of total concentrations. Meanwhile, there was a lack of the standardized derivation method. On such a basis, we put forward some suggestions to improve GB 15618-2018 in light of the aforementioned problems, including strengthening the research of soil environmental benchmark and background values; establishing the scientific and standardized derivation method; and improving the number, form, and availability of indicators for risk control. In the meantime, the regional and local background environmental concentration of soil was highly proposed as a supplement and optimization to soil screening values.

于2018年对上海市青浦区现代农业园内全水稻生育期内稻田田面水以及地下30和60 cm深度淋溶水进行采样,获取了田面水和淋溶水氮磷指标数据.采用主成分分析法(principal component analysis,PCA)和聚类分析法(cluster analysis,CA)筛选出该区域水稻田田面水和淋溶水中氮磷监测指标,并分别建立该区域水稻田氮磷监测指标的最小数据集(minimum data set,MDS),比较基于聚类分析的最小数据集水质综合得分(water quality index-CA,WQI-CA)、基于主成分分析的最小数据集水质综合得分(water quality index-PCA,WQI-PCA)和全量数据集水质综合得分(water quality index-total data set,WQI-TDS).结果表明:(1)应用主成分分析和聚类分析均可从稻田田面水以及30和60 cm深度淋溶水的8项氮磷监测指标中筛选出3～4项组成监测指标最小数据集;(2)基于不同数据集的稻田水质综合得分结果差异明显,水质综合得分变化范围和均值表现为WQI-PCA较WQI-CA更接近于WQI-TDS,并且WQI-PCA与WQI-TDS的Nash有效系数和相关度均高于WQI-CA,这表明基于主成分分析的最小数据集(MDS-PCA)较基于聚类分析的最小数据集(MDS-CA)更适合替代全量数据集作为稻田水质污染的监测与评价指标.

泥沙指纹技术是近年来研究流域泥沙来源与动态变化的一项重要技术方法,其主要局限性在于诸多的前提假设与实践条件的差异带入了一系列不确定性.泥沙从源到汇的迁移过程受自然环境和人为干扰的影响,其源地特征、迁移路径以及泥沙性质的潜在变化等均是指纹技术应用的不确定性因素,而采样方案设计、指纹选择方法、混合模型应用的一些主观因素进一步增加了不确定性的来源.不确定性分析是泥沙指纹技术的重要组成部分,是评估泥沙来源指纹识别结果可靠性的主要依据.本文综述了泥沙指纹技术的诸多不确定性问题以及主要应对方法的研究进展,总结了当前不确定性定量评估的研究现状并提出了未来的研究展望.

泥沙来源信息有助于研究流域土壤侵蚀、泥沙输移与沉积特征,对于制定流域泥沙及非点源污染控制战略具有重要意义.泥沙指纹技术是识别泥沙来源的一个可靠方法被广泛应用于世界各地不同流域,最近20多年在指纹因子选择和混合模型优化等技术方法上以及不同时空尺度和源地分类等应用类型上都得到了快速发展,正在从一种研究工具逐步发展为一种管理工具.综述了国内外指纹技术识别泥沙来源在研究尺度、指纹因子筛选、源地贡献分配、不确定性分析等方面开展的研究,并对泥沙指纹技术研究当前存在的问题及今后研究趋势作了分析展望.

为调查江苏省滆湖主要入湖河流水质变化特征和滆湖主要污染物来源,对扁担河、夏溪河、湟里河、北干河、中干河等5条入湖河流进行了为期1年的水量水质监测,并计算分析了主要入湖污染物通量和滆湖沉积物中氮磷释放量.结果表明,入湖河流中高锰酸盐指数含量为2.7~8.9 mg/L、氨氮含量为0.21~3.59 mg/L、总氮含量为0.39~4.59 mg/L、总磷含量为0.236~0.624 mg/L;5条入湖河流年径流量为8.04×108m3/年,径流量大小排列次序为扁担河>北干河>湟里河>中干河>夏溪河;5条入湖河流主要污染物通量总磷为174.28 t/年、氨氮为865.46 t/年、总氮为1654.75 t/年、化学需氧量(COD)为16219.74 t/年,主要污染物入湖通量大小排列次序为扁担河>湟里河>北干河>夏溪河>中干河;滆湖底泥中沉积的氮、磷总量分别为44370、18168 t,每年向水体释放的总氮、总磷量分别为562.22、19.16 t.

Mercury (Hg) contamination in soil-rice systems from industry, mining and agriculture has received increasing attention recently in China. Pot experiments were conducted to research the Hg accumulation capacity of rice under exogenous Hg in the soil and study the major soil factors affecting translocation of Hg from soil to plant. Soil treated with 2 mg kg−1 Hg decreased rice grain yield and inhibited the growth of rice plants. With increased Hg contamination of the rice, the enrichment rate of Hg was significantly higher in the rice grain than that in the stalk and leaf. Soil pH and cation exchange capacity are the key factors controlling Hg bioavailability in soils.

水稻是我国主要的粮食作物之一.水稻生产过程中土壤和肥料中的部分氮磷元素以溶质或颗粒形态通过淋溶、径流迁移至周围水体,造成地下水污染和水体富营养化.稻田土壤中氨挥发产生的氨气和反硝化反应产生的氧化亚氮气体进入大气,加剧了温室效应.笔者围绕稻田氮磷的气体挥发、径流和淋溶3个流失途径介绍了国内外常用的监测方法,并进一步讨论了针对径流和淋溶这2种流失途径的监测指标、监测频率和监测深度等问题,总结了2种流失途径的主要氮磷流失形态,根据产流特征和施肥时间确定监测时间节点,综合考虑植物吸收和地下水深度确定淋溶监测深度,以期为稻田氮磷流失监测提供相关技术支持和科学依据.

在全自动甲烷潜力测试系统中,以瘤胃液为接种物,研究了谷类秸秆(水稻、小麦和高粱)的产酸产甲烷性能和三维荧光光谱特征.结果表明,奶牛瘤胃微生物对谷类秸秆表现出很强的水解酸化能力.经过5d厌氧消化,水稻、小麦和高粱秸秆单位质量挥发性固体(VS)的总挥发性脂肪酸(TVFAs)产率分别达410.9、430.9和472.0 mg·g-1.谷类秸秆的产甲烷规律符合改进型Gompertz模型.经过55 d的厌氧消化,水稻、小麦和高粱秸秆(以VS计)的甲烷产量分别为66.29、103.79和76.89 mL·g-1.通过三维荧光光谱耦合平行因子分析(PARAFAC)识别溶解性有机物的3个有效荧光组分,3个组分分别为酪氨酸类物质、色氨酸类物质和低分子量腐殖酸类物质.其中,色氨酸类物质的荧光强度与TVFAs浓度呈幂函数关系.谷类秸秆溶解性有机物的腐殖化指数(HIX)经过5 d厌氧消化后降低,而后呈现逐渐上升趋势.

Based on the status of pollution load and its prediction methods,the pollution load of level year of Dongzhen Reservoir basin was predicted.The results showed that the pollution mainly came from agricultural non-point source pollution,domestic sewage and domestic garbage,of which orchard non-point pollution was the major source.Based on the prediction results of pollution load Dongzhen Reservoir basin,a two-dimensional water quality mathematical model was constructed for the purpose of evaluating the change trend of water quality.The results showed that total nitrogen and total phosphorus can't meet Grade Ⅲ of Surface Water Quality Standard.Consequently,it was suggested to strengthen environmental protection of Dongzhen Reservoir,focusing on orchard non-point source pollution control,domestic sewage and garbage disposal.

Livestock and poultry breeding farms different in scale vary in management mode, and in pollution generation characteristic, too. Studying their pollution generation characteristics relative to scale of the farm may help provide some scientific basis for rational regional waste utilization and pollution control. Two pig farms different in scale in Tiaoxi Basin were selected for the study, samples of wastewater and pig feces generated in these two pig farms were collected for analy?sis to characterize, pollutant contents in the wastewater and feces and pollution generation coefficient of the farms different in scale at different stages. Results show that the Jinai Farm ( annually 500 pigs sent to the slaughterhouse) was higher than in the Daguanshan Farm ( annually 36000 pigs sent the slaughterhouse) in average daily production of breeding sew?age and feces per pig;the Daguanshan Farm was higher than the Jinai Farm in pollution content ( except for P ) in the sew?age and feces;the Jianai Farm was much too higher than the Daguanshan Farm in content of total phosphorus(TP) in the pig waste, which might result from the use of swill as feed, which was higher in TP. Pollution generation coefficient varied with pig breeding stage. In the Daguanshan Farm, generation coefficient reached 8. 94, 18. 68 and 30. 65 g·d-1 for TN and 3. 91, 7. 62 and 14. 77 g·d-1 for TP, respectively, at the stage of nursery, fattening and gestation in the Daguanshan Farm, and 9. 84, 19. 77 and 32. 95 g·d-1 for TN, and 5. 87, 15. 23 and 30. 09 g·d-1 for TP, respectively, at the Jinai Farm. Apparently, the Daguanshan Farm was slightly higher than the Jinai Farm in total nitrogen ( TN) pollutant genera?tion, but much lower in TP pollutant generation coefficient and the two farms were quite similar in heavy metal pollutants generation coefficient, which demonstrate that scale of a pig farm is a major factor affecting TP pollutant generation coeffi?cient, but a minor one affecting TN and heavy metal pollutant generation coefficients.

Universal Soil Loss Equation (USLE) model and GIS were used to evaluate soil erosion in Longdun Reservoir watershed of Nanjing. The results showed that Longdun Reservoir watershed was moderately eroded, and the average soil erosion modulus was 4 343.46 t/km2. More than 63% of the watershed area was at the level of micro or slight erosion. The watershed area with severe erosion was very small, but it contributed to more than 70% of soil erosion amount. Soil erosion in this watershed varied with land use types, and the annual average soil erosion modulus followed the order: upland field > grass > paddy field > forest land, and the soil erosion amount followed the order: upland field > paddy field > grass > forest land. The watershed was divided into 13 sub-watersheds by GIS. The sub-watersheds 4, 5 and 10 were the areas with large soil erosion modulus, and the more attentions need to be paid to the sub-watershed 10 because of its large soil erosion modulus and soil erosion amount. The sub-watersheds 1, 9 and 12 should also be taken care of due to their large soil erosion amounts. Soil erosion amount in all sub-watersheds mainly came from the areas with high erosion grades and severe erosion. Therefore, the more attentions should be paid to the areas with high erosion potentials when the control measures are taken to inhibit soil erosion in future.

Mercury contamination in agro-ecosystems is one of the most important environmental issues. Farmland soil mercury accumulation and transference to crops in Changshu City, eastern China, were investigated to identify mercury migration capacity from soil to crops. The mean content of mercury for soil samples slightly increased year after year. The mercury accumulation capacity of rice grown (bioaccumulation factor (BAF) 0.028) in submerged soils under reductive conditions was stronger than that of wheat (BAF 0.0073) in dried soils under oxidative conditions. There were clear relationships between soil mercury with organic matter (OM), cation exchange capacity (CEC), and CaCO3 of soil samples, while apparent negative relationships between Hg in rice grain with OM, CEC, and CaCO3 of soil existed. No clear association for Hg between crops and soil was found, indicating that mercury in crop grains is mostly affected by other factors besides soil mercury. Also, soil properties and farming patterns affected mercury transference from soil to crop grains and mercury enrichment capacity in crop grains. The results suggested that appropriate selection of crop species and water management are two major possible ways to reduce total mercury accumulation in crop grains grown in mercury-contaminated regions.

海伦市是以农业为主导产业的黑龙江省县级市,为了解该市土壤重金属及磷素现状,2008年采集了农田耕层土样95个、亚耕层土样95个和土壤剖面分层土样92个,分析了其中的Cu、Zn、Cr、Ni等重金属全量和磷的含量.在前期结果的基础上,2009年又选取8个土壤剖面来进一步研究磷在垂直深度上的分布特征.结果表明,该市耕层土壤重金属含量总体较低,与松嫩平原土壤元素背景值相比较,出现一定程度的富集.与第二次土壤普查结果相比较,有效磷的富集趋势明显.从空间分布图上可以看出总磷和有效磷的分布与重金属的分布呈现了完全不同的趋势,重金属主要来源可能来自土壤母质,化学磷肥对重金属的含量有一定影响,但不是主要因素.大量施加磷肥也是该地区有效磷大幅增加的主要原因之一.重金属和磷含量随着土层的加深都呈现先下降再上升的趋势,有效磷的含量在各发生层差异比较明显.进一步的磷剖面结果显示:有效磷和水溶磷含量总体趋势是随着深度的增加都先急剧下降,表层磷富集趋势明显,并有向下迁移的趋势,随后呈现含量稳定、缓慢上升或者巨大波动3种趋势,这与耕作历史、耕作方式及所种植的作物类型等有关.

施加粪肥是提高土壤肥力的重要措施,为了解粪肥磷在潮土中的化学行为,通过室内培养试验,采用NaOH-EDTA浸提和31p核磁共振技术分析比较了鸡粪、牛粪及施肥后土壤中的磷形态及含量,并研究了施肥对潮土有效磷的影响.结果表明,粪肥磷主要以无机态形式存在,2种粪肥的有机磷形态及含量有明显不同,肌醇六磷酸在鸡粪中的含量明显高于牛粪.粪肥施加到潮土后丰富了土壤有机磷的形态.随时间延长,潮土中各形态磷发生相互转化,以肌醇六磷酸为主的正磷酸单酯含量明显降低,核酸等正磷酸双酯显著升高.鸡粪处理的土壤有效磷含量逐渐升高,牛粪处理则表现出相反的趋势.施加粪肥后,土壤有效磷呈现不同的变化规律可能是无机磷在土壤中固定或沉淀,有机磷矿化和无机磷被微生物固持这三方面综合作用的结果.

With the rapid and stable development of agricultural economy,agricultural non-point source pollution problems become more and more serious,has become the focus of attention. Improving the rural environment,rural landscape restoration and the sustainable development of agriculture has become today's theme. A comprehensive analysis and study on agricultural non-point source pollution in China and prevention technology was made,and the agricultural system of pollution prevention strategies in existing technical conditions was summarized. Evaluation index system from three aspects were established: the goal realization degree,influence factors,public satisfaction degree,and the evaluation methods were discussed,and the evaluation problems and suggestions were put forward.

海伦市是以农业为主导产业的黑龙江省县级市,为了解该市土壤重金属时空分布特征及其污染现状,对农田耕层及亚耕层土壤中Cd、Cr、Cu、Ni、Pb、Zn、Hg和As等重金属全量进行了分析,并采用单因子污染指数法和Nemerow综合污染指数法分别对土壤的重金属污染状况进行了评价.结果表明,该地区土壤重金属含量较低,总体表现为西南和西北含量较高、西部含量高于东部的空间分布特征,以松嫩平原土壤元素背景值为标准进行评价,已出现一定程度的污染.以GB15618-1995土壤环境质量标准二级标准进行评价,综合污染指数为0.504,所有样点土壤重金属均未达到污染水平,与耕层土壤相比,亚耕层土壤Hg和Cd含量显著下降,其他元素含量及分布特征则与耕层相似.从1980年到2008年,随着时间的变化,该区域土壤重金属含量增加趋势不明显,近期土壤出现重金属污染风险较小.