造纸废水灌溉对黄河三角洲退化湿地可培养土壤微生物的影响

利用造纸废水恢复重度退化湿地,分析了土壤微生物数量、土壤呼吸强度及微生物量碳的变化情况。结果表明,灌溉后,8月份,细菌和真菌数量最多,放线菌5月份数量最多;细菌、真菌、放线菌各灌水深度上层大于中层,各灌水深度、细菌、真菌、放线菌上层数量均大于对照;土壤呼吸主要发生在表层（0~20 cm）;8月份,微生物量碳达到最大值690.3 mg/kg,且上中下层依次递减。相关分析表明,15 cm灌水量,土壤呼吸强度与有机碳呈极显著正相关（r=0.996,P=0.0036）,灌水量为0、5、10和20 cm,土壤微生物量碳与有机碳呈极显著正相关(r=0.999,0.999,0.999;P<0.001),15 cm灌水量,微生物量碳与速效磷呈极显著正相关（r=0.972,P=0.028）;5 cm灌水量,微生物总数与有机碳呈显著线性正相关（r=0.953,P=0.047）,对照和15 cm灌水量,微生物总数与速效磷呈显著正相关（r=0.976,P=0.024;r=0.968;P=0.032）。灌溉处理后的造纸废水,可增加重度退化湿地土壤微生物的活性,改善土壤质量。     

Heavy metals in coastal wetland sediments of the Pearl River Estuary, China

Sediment quality in coastal wetlands of the Pearl River Estuary was concerned since the wetlands were used for land reclamation, aquaculture and wildlife protection, and meanwhile served as one of the main ultimate sinks for large amount of heavy metals discharged from the rapidly developing Pearl River Delta. Total concentrations of heavy metal, such as Zn, Ni, Cr, Cu, Pb, and Cd, and their chemical speciation were investigated. Results showed that the sediments were significantly contaminated by Cd, Zn and Ni with concentration ranges of 2.79-4.65, 239.4-345.7 and 24.8-122.1mg/kg, respectively. A major portion (34.6-46.8%) of Pb, Cd, and Zn was strongly associated with exchangeable fractions, while Cu, Ni and Cr were predominantly associated with organic fractions, residual, and Fe-Mn oxide. Cd and Zn would be the main potential risk and the sediment quality is no longer meeting the demand of the current wetland utilization strategies.     

The responses of two native plant species to soil petroleum contamination in the Yellow River Delta,China

Environmental Science and Pollution Research - Petroleum contamination is a significant environmental problem in the Yellow River Delta. The responses of two native salt-tolerant plant species,...     

Assessment and potential sources of metals in the surface sediments of the Yellow River Delta,Eastern China

The Yellow River Delta is the most intact estuary wetland in China and suffers from great pressure of metals. Seventy-seven surface sediment samples were collected in the delta, and contents of Cu, Pb, Cd, Cr, Zn, Ni, and Mn were analyzed by inductively coupled plasma spectrometry and those of Hg and As by atomic fluorescence spectrometry. The results showed that means of metal contents (ppm, dry weight) were as follows: Hg, 0.04; Cr, 61.72; Cu, 20.97; Zn, 60.73; As, 9.47; Pb, 21.91; Cd, 0.12; Ni, 27.24; and Mn, 540.48. 43.8% of Hg and 14.3% of Cd were from the allogenic source while others from the authigenic source. The results of the geoaccumulation indexes appeared that 6.5% of sites from the estuarine and the Gudao areas were moderately polluted by Hg. All ecological risk index values of Hg and 37.7% of Cd were more than 40, which were the main factors of strongly and moderately potential ecological risks of 37.7% of sites in the delta. High Cd contents may be due to the alkaline conditions of the delta and the unreasonable management of the farmland, while the abnormal distribution of Hg to the wet or dry deposition and the erosion of the seawater. It was suggested to monitor Hg content in the atmosphere of the Yellow River Delta. The results were expected to update the pollution status of metals in the delta and created awareness of preserving the sound condition of the Yellow River Delta.     

Polybrominated diphenyl ethers in soils of the modern Yellow River Delta, China: occurrence, distribution and inventory

The Yellow River is the second largest river in China. In this study, the levels of polybrominated diphenyl ethers (PBDEs) in the modern Yellow River Delta (mYRD) were firstly reported. Twenty PBDE congeners in soil/sediment samples from mYRD were measured. The total PBDE concentrations ranged from non-detectable to 18 257 ng kg⁻¹ with a mean value of 836 ng kg⁻¹. BDE-209 was the dominant congener, accounting for ∼86.1-99.5% of the total PBDEs. The congener profiles of PBDEs with higher abundances of BDE-153 and BDE-183 were similar to those in sediment of the Bohai Sea, indicating that they shared similar sources. The concentrations and congener patterns varied among different regions. Higher levels of PBDEs were found in the middle area (MA), and more complicated congener compositions were also observed in the MA, whereas lower levels of PBDEs were found in the modern course (MC) and the old course (OC). Much more PBDEs were detected in the top layer (TL) soil where more congeners were also held compared to lower soil layers, implying that more PBDEs were emitted into this area in recent years/decades. Organic matter controlled the PBDE distribution in the soil. Soil in this area might be a source of BDE209 for the Bohai Sea.     

Environmental monitoring of spatial-temporal changes using remote sensing and GIS techniques in the Abandoned Yellow River Delta coast, China

On the basis of remote sensing and GIS techniques, the Landsat data obtained in 1978, 1987 and 2000 were used to examine coastline changes in the Abandoned Yellow River (AYR) Delta in China. The coastal land lost and gained illustrations were derived from the extracted coastlines, the rates of coastal change were estimated, and the coastal parts that experienced the biggest changes were identified. The results illustrated that the erosion rates of the AYR Delta coast decreased during 1978-2000 while the erosion effect remained strong. The spatial-temporal changing patterns of the northern, central and southern coastal parts in the study area were characterised by slow erosion, erosion and dynamic balance of erosion/accretion.     

Analyzing trophic transfer of heavy metals for food webs in the newly-formed wetlands of the Yellow River Delta, China

Nine heavy metals sampled from water, sediments, and aquatic organisms in the newly-formed wetlands of the Yellow River Delta (YRD) of China were analyzed to evaluate their concentrations and trophic transfer in food webs. The stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes were used to investigate trophic interactions. Results show that most of heavy metals detected in water and sediments are lower than that in Yangtze River Delta and Pearl River Delta. The longest food web is approximately 4 with the highest trophic level of birds. The difference of heavy metal concentrations between endangered Saunders’s Gull and other three kinds of protected birds is not obvious. Cd, Zn, and Hg were identified to have an increase with the trophic level (TL), while As, Cr, Cu, Mn, Ni and Pb show an opposite trend, however, the biomagnification of the selected nine heavy metals in the food webs is not significant.     

Assessment of metal and nutrient concentrations in river water and sediment collected from the cities in the Pearl River Delta,South China

The effects of anthropogenic activities, industrialization and urbanization on the accumulation of heavy metals and nutrients in sediments and water of rivers in the Pearl River Delta region were examined. Most sediments were seriously contaminated with Cd, Pb, and Zn in accordance with the classification by Hong Kong Environmental Protection Department. Total phosphorus (P) and nitrogen (N) concentrations in sediments ranged from 0.02% to 0.12% and 0.06% to 0.64%, respectively. High carbon (C), N, P and sulphur (S) levels at Yuen Long Creek were related to the discharge of industrial effluents along the river. The enrichment of P and ammoniacal-nitrogen (NH4+-N) in water were obvious. For most sites, the P concentration exceeded 0.1 mg/l, which is the recommended concentration in flowing water to encourage excessive growth of aquatic plants. Nine out of the 16 sites studied had NH4+-N concentration over 2 mg/l. The rivers in the south of Deep Bay (Hong Kong) had high nutrient exports compared with the rivers in the east region and western oceanic water. The concentrations of nitrate-nitrogen NO3--N in surface water were under the maximum contaminant level in public drinking water supplies (10 mg/l) except for one site. Although the concentrations of heavy metals in overlying water were low, their accumulations were significant. High contents of nickel (Ni) and zinc (Zn) in water were found at certain locations, suggesting the occurrence of some local contamination. These preliminary results indicated that river and sediment transported pollutants is likely one of the factors for the water quality degradation of Deep Bay water.     

Spatial trend and pollution assessment of total mercury and methylmercury pollution in the Pearl River Delta soil, South China

Total mercury (THg) and methylmercury (MeHg) were measured in large number of soil samples collected from areas with different types of land use, different depth in the Pearl River Delta (PRD) of South China. THg and MeHg concentrations ranged from 16.7 to 3320 ng g⁻¹ and 0.01 to 1.34 ng g⁻¹, respectively. THg levels are highest in the top 0-20 cm soil layer, and decrease from the surface to bottom layer soil. Spatial variation was observed with different types of land use. Urban parks had the highest concentrations and the other areas tended to decrease in the order of residential areas, industrial areas, vegetable fields, cereal fields, and woodlands. Temporal variation was also noted, and two relatively high THg contamination zones located in the northwestern part of the PRD have significantly expanded over the last two decades. Both THg and MeHg concentrations were correlated significantly with soil organic matter (OM), but not with soil pH. THg pollution status was evaluated using two assessment methods.     

Distribution of polycyclic aromatic hydrocarbons in thirty typical soil profiles in the Yangtze River Delta region, east China

Polycyclic aromatic hydrocarbons (PAHs) were quantified in 30 soil profiles from the Yangtze River Delta Region, in east China. Relative concentrations of PAH compounds with different benzene rings and ratios of fluoranthene to fluoranthene plus pyrene and benz(a)anthracene to benz(a)anthracene plus chrysene were used to identify the possible sources of soil PAHs. Total concentrations of 15 PAHs in topsoils ranged from 8.6 to 3881 microg kg(-1) with an average of 397 microg kg(-1). Half of the soil samples were considered to be contaminated with PAHs (>200 microg kg(-1)) and two sampling sites were heavily polluted by PAHs with concentrations >1000 microg kg(-1). Phenanthrene was found in soils below a depth of 100 cm in half of the sampling sites, but the detectable ratio of benzo(a)pyrene decreased sharply from 100% in topsoil to 0 in the 4th horizon.     

北方滨海人工湿地水生生物群落重建效果评估——以天津临港湿地二期生态重建工程为例

为准确评估滨海人工湿地生态重建成效,科学指导工程改进方案,以重建近1年的天津临港湿地二期生态重建工程为例,通过调查重建前(2020年)和重建后(2021年)湿地水生生物群落组成变化,评价湿地生物群落重建效果。结果表明：经过近1年的生态重建,鱼类群落和底栖动物群落均得到不同程度恢复;鱼类的种类由重建前的未检出增加到10种,除泥鳅、梭鱼等增殖先锋物种未得以恢复外,其他增殖鱼类均长势良好;随着物理生境改善和先锋物种的直接投加,底栖动物数量由重建前的11种提高到重建后的28种,生物多样性明显提高;在类群组成上,底栖动物群落以自然恢复的摇蚊幼虫为主,人工投放的大型底栖物种恢复进程相对缓慢;鱼类增殖放流加剧了对浮游动物的捕食压力,造成浮游动物生物量降低和个体减小,进而导致浮游植物群落的快速响应和结构变化。基于上述研究结果,提出了水生生物群落重建优化调控建议。本研究成果可为北方滨海人工湿地重建提供借鉴。     

Spatial and temporal variations of nitrous oxide flux between coastal marsh and the atmosphere in the Yellow River estuary of China

To investigate the spatial and seasonal variations of nitrous oxide (N₂O) fluxes and understand the key controlling factors, we explored N₂O fluxes and environmental variables in high marsh (HM), middle marsh (MM), low marsh (LM), and mudflat (MF) in the Yellow River estuary throughout a year. Fluxes of N₂O differed significantly between sampling periods as well as between sampling positions. During all times of day and the seasons measured, N₂O fluxes ranged from ?0.0051 to 0.0805 mg N₂O m^?2 h^?1, and high N₂O emissions occurred during spring (0.0278 mg N₂O m^?2 h^?1) and winter (0.0139 mg N₂O m^?2 h^?1) while low fluxes were observed during summer (0.0065 mg N₂O m^?2 h^?1) and autumn (0.0060 mg N₂O m^?2 h^?1). The annual average N₂O flux from the intertidal zone was 0.0117 mg N₂O m^?2 h^?1, and the cumulative N₂O emission throughout a year was 113.03 mg N₂O m^?2, indicating that coastal marsh acted as N₂O source. Over all seasons, N₂O fluxes from the four marshes were significantly different (p?<?0.05), in the order of HM (0.0256?±?0.0040 mg N₂O m^?2 h^?1)?>?MF (0.0107?±?0.0027 mg N₂O m^?2 h^?1)?>?LM (0.0073?±?0.0020 mg N₂O m^?2 h^?1)?>?MM (0.0026?±?0.0011 mg N₂O m^?2 h^?1). Temporal variations of N₂O emissions were related to the vegetations (Suaeda salsa, Phragmites australis, and Tamarix chinensis) and the limited C and mineral N in soils during summer and autumn and the frequent freeze/thaw cycles in soils during spring and winter, while spatial variations were mainly affected by tidal fluctuation and plant composition at spatial scale. This study indicated the importance of seasonal N₂O contributions (particularly during non-growing season) to the estimation of local N₂O inventory, and highlighted both the large spatial variation of N₂O fluxes across the coastal marsh (CV?=?158.31 %) and the potential effect of exogenous nitrogen loading to the Yellow River estuary on N₂O emission should be considered before the annual or local N₂O inventory was evaluated accurately.     

Water pollution and degradation in Pearl River Delta,South China

The Pearl River Delta Economic Zone is the most dynamic economic area in South China. One of the major problems in the region is the sustainable utilization of the water resources. On the basis of analysis of the water environment status and pollution sources, it is suggested that domestic sewage is the primary cause of pollution. Two new concepts "degradation coefficient" and "degradation volume" of water resources, due to pollution, which may be used to assess macroscopically the carrying capacity of the water resources and sustainability of the water environment, are proposed by the authors. The results calculated indicate that the volumes of degraded water resources will be up to 204, 352, and 537 million m3 in 2002, 2010, and 2020. It is suggested that water for daily consumption and domestic sewage must be controlled more effectively and there should be cross-regional coordination in tackling problems of water environment.     

Distribution of alkylphenols in the Pearl River Delta and adjacent northern South China Sea, China

The occurrence of alkylphenols (APs) was investigated in surface water and sediments from the Pearl River Delta and adjacent northern South China Sea. Most of the water samples contained detectable amounts of APs, ranging up to 0.628 microg l(-1) for nonylphenol (NP) and 0.068 microg l(-1) for octylphenol (OP). APs were found in all of the sediment samples with concentrations ranging from 59 to 7808 microg kg(-1) for NP and from 1 to 93 microg kg(-1) for OP. The Zhujiang River showed the highest concentrations of APs in both water and sediments. Significant decrease of APs concentrations going from the Zhujiang River to the Shiziyang River was observed. The Xijiang River contained concentrations of APs slightly higher in water but relatively lower in sediments than the Lingding Bay, which might be attributed to their different hydrodynamic and sedimentary characteristics. There was a decreasing trend of APs in water from the rivers to the estuary and further to the sea on the whole. In the Lingding Bay and its outer waters, concentrations of APs in sediments increased to a maximum and then decrease seaward, which was consistent with the distribution trend of the sediment organic carbon contents. Linear regression analyses showed the concentrations of APs were markedly correlated with the sediment organic carbon contents, indicating that the sediment organic carbon is an important factor controlling the levels of APs in sediments.     

Effects of fungicides triadimefon and propiconazole on soil bacterial communities

The impact of fungicides triadimefon and propiconazole on soil bacterial populations from a strawberry field was investigated. Two fungicides were applied to the soil at concentrations of 10 mg/kg or 100 mg/kg with soil water contents 20.2% (fresh soil water content) or 26.0% (field capacity). Changes in bacterial communities were assessed using DNA extraction, polymerase chain reaction (PCR) amplification of the 16S rDNA and denaturing gradient gel electrophoresis (DGGE). High performance liquid chromatography (HPLC) was utilized to detect the residue of fungicides in soils. The results showed that propiconazole was more persistent than triadimefon in soils, and the two soil water contents did not cause significant differences in dissipation rates between the two fungicides. A high concentration of propiconazole could inhibit the existence of soil microbes while one of triadimefon might induce the microbial population in the first stage. From unweighted pair-group method using arithmetic averages (UPGMA) dendrograms, the effect of triadimefon and propiconazole at the two applied concentrations on a soil bacterial community could be long term. After triadimefon was applied for 60 days and propiconazole for 75 days, the compositions of microbial communities were not recovered. From the viewpoint of environmental protection, it was of significant importance to pay more attention not only to the residues of pesticide but also to the change in soil microbial communities.     

Levels and distribution of Dechlorane Plus in coastal sediments of the Yellow Sea, North China

Dechlorane Plus (DP) has been determined in surface sediments from three Chinese coastal bays, e.g. Jiaozhou, Sishili and Taozi Bay in North China. DP concentrations ranged from <1.2 to 187 pg g⁻¹ dry weight (dw) (mean: 24.7 pg g⁻¹ dw) in Jiaozhou Bay, <1.2 to 135 pg g⁻¹ dw (mean 69.9 pg g⁻¹ dw) in Sishili Bay and <1.2 to 66.7 pg g⁻¹ dw (mean: 40.4 pg g⁻¹ dw) in Taozi Bay, respectively. Additionally, two dechlorinated species were quantified, which accounted for 0.6-5.1% of the ∑DP concentration.The f_syn values (syn-isomer/(syn- + anti-isomer)) in sediments from Jiaozhou Bay (mean 0.29) were close to the technical DP mixture (0.2-0.4), probably indicating local inputs of DP. In contrast, sediments in Sishili and Taozi Bay showed much lower f_syn values (mean 0.16). During transportation the DP isomers are subject to stereo selective degradation which partly resulted in the relative enrichment of anti-DP in coastal sediments.     

珠江三角洲潮土和水稻土酸缓冲特性试验研究

珠江三角洲潮土和水稻土对不同种类的酸具有一定的缓冲性,不同种类的酸对不同类型土壤的酸化趋势不同。大旺水稻土对酸的敏感性强于龙山潮土,龙山潮土属于稍易受害的稍敏感土壤,大旺水稻土属于易受害的敏感土壤;同一土壤对酸的缓冲能力比对碱的缓冲能力强;不同种类的酸对土壤的敏感性不同,土壤对硝酸的敏感性强于对硫酸的敏感性;土壤加酸后酸缓冲曲线和土壤中铝释放曲线的交点可以作为衡量土壤对酸敏感性的指标,交点越低,敏感性越强;加酸后土壤中铝的释放可以用模型y=nx+k来预测。     

Heavy metals in agricultural soils of the Pearl River Delta,South China

There is a growing public concern over the potential accumulation of heavy metals in agricultural soils in China owing to rapid urban and industrial development and increasing reliance on agrochemicals in the last several decades. Excessive accumulation of heavy metals in agricultural soils may not only result in environmental contamination, but elevated heavy metal uptake by crops may also affect food quality and safety. The present study is aimed at studying heavy metal concentrations of crop, paddy and natural soils in the Pearl River Delta, one of the most developed regions in China. In addition, some selected soil samples were analyzed for chemical partitioning of Co, Cu, Pb and Zn. The Pb isotopic composition of the extracted solutions was also determined. The analytical results indicated that the crop, paddy and natural soils in many sampling sites were enriched with Cd and Pb. Furthermore, heavy metal enrichment was most significant in the crop soils, which might be attributed to the use of agrochemicals. Flooding of the paddy soils and subsequent dissolution of Mn oxides may cause the loss of Cd and Co through leaching and percolation, resulting in low Cd and Co concentrations of the paddy soils. The chemical partitioning patterns of Pb, Zn and Cu indicated that Pb was largely associated with the Fe-Mn oxide and residual fractions, while Zn was predominantly found in the residual phase. A significant percent fraction of Cu was bound in the organic/sulphide and residual phases. Based on the 206Pb/207Pb ratios of the five fractions, it was evident that some of the soils were enriched with anthropogenic Pb, such as industrial and automobile Pb. The strong associations between anthropogenic Pb and the Fe-Mn oxide and organic/sulphide phases suggested that anthropogenic Pb was relatively stable after deposition in soils.     

Polycyclic aromatic hydrocarbons in the surface sediments from Yellow River, China

Fourteen surface sediment samples were collected from Lanzhou Reach of Yellow River, China in July 2005. The concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector (GC-MS). Total concentrations of the PAHs ranged from 464 to 2621 ng/g dry weight. Sediment samples with the highest PAH concentrations appeared at the downstream of Lanzhou City, where there was the biggest wastewater discharge pipeline from Lanzhou Oil Refinery Factory and Lanzhou Chemical Industry Company. Municipal sewage also contributed to the PAH contamination in the sediments. A correlation existed between the sediment organic carbon content (f(oc)) and the total PAH concentrations (r(2)=0.57), suggesting that sediment organic carbon content played an important role in controlling the PAHs levels in the sediments. According to the observed molecular indices, PAHs contamination in Lanzhou Reach of Yellow River originated both from the high-temperature pyrolytic processes and from the petrogenic source, showing a mixed PAH input pattern, which was also confirmed by the results of a principal component analysis (PCA). According to the numerical effect-based sediment quality guidelines (SQGs) of the United States, the levels of PAHs at most studied sites in Lanzhou Reach of Yellow River should not exert adverse biological effects. Although at some sites (such as S10, S12, etc.) one PAH may exceed the effects range low (ERL), individual PAH did not exceed the effects range median (ERM). The results indicated that sediments in all sites should have potential biological impact, but should have no impairment.