Heavy metal pollution impacts on soil microorganisms are of growing concern. This study employed high-throughput sequencing and qPCR to investigate rhizosphere microbial communities and functional genes responses in ryegrass (Lolium perenne L.) under cadmium (Cd) stress. Results showed dose-dependent shifts in microbial diversity, metabolic pathways and functional gene abundance. The relative abundances of bacterial classes Alphaproteobacteria and Bacteroidia and genera Cellvibrio and Algoriphagus increased with Cd levels, suggesting roles in Cd adaptation. The classes Actinobacteria, Saccharimonadia, and Acidimicrobiia and the genera Rheinheimera, Pseudomonas, and Sphingomonas decreased. The fungal genera Acremonium, unclassified Hypocreales, Cladosporium and Paramyrothecium increased under high Cd, while Albifimbria, Fusarium, and Ramichloridium decreased. Differential adaptive strategies to Cd toxicity were observed between bacterial and fungal phyla. Redundancy analysis identified pH, EC, TN, and Cd as key determinants of microbial variation. FAPROTAX prediction revealed significant changes in dominant functional groups involved in nutrient cycling, and FunGuild analysis indicated increased saprophytic fungi with elevating Cd levels, potentially enhancing detoxification. Functional genes related to nitrogen and carbon cycling also varied with Cd gradients. This study systematically elucidated the response of rhizosphere soil microbial communities and functional gene abundance to Cd stress, providing mechanistic insights for developing ryegrass tolerance strategies.

Tidal flow constructed wetland (TFCW) creates an anaerobic/aerobic alternating environment through tidal operation, greatly enhancing oxygen supply. Here, we review the state of the art on the mechanisms, influencing factors, removal effectiveness and electrochemically enhanced technologies of TFCWs, highlighting their feasibility and flexibility. The unique hydraulic conditions (e.g. the flooding/resting duration ratio) of TFCWs work synergistically with the substrate, plants and microorganisms in the environment to effectively remove both conventional and emerging pollutants. The influent carbon-to-nitrogen ratio and the temperature also influence their removal. Generally, total suspended solids and the biochemical oxygen demand are removed at high levels. Reduction of the chemical oxygen demand varies, tending to improve with longer flooding/resting duration ratios when sufficient dissolved oxygen is present during the flooding phase. Ammonium removal has been widely reported, primarily by substrate adsorption and microbial nitrification. By contrast, the removal of nitrate and nitrite is highly variable and they often accumulate in the system. Total phosphorus and phosphate removal also fluctuates. Additionally, limited research has indicated that heavy metals, pharmaceutical and personal care products and antibiotic resistance genes are effectively removed in TFCWs. To further enhance the removal performance, electrochemical technologies (e.g. electrolysis, iron-carbon micro-electrolysis, microbial fuel cells) have been successfully integrated into TFCWs and proven to be effective. Future research should prioritise novel functional substrate testing, long-term evaluations using real wastewater to assess the robustness of systems against more pollutants, mechanistic studies under tidal dynamics, pilot to full-scale applications, and process modelling with comprehensive assessments to guide system optimisation.

Reclaimed water and sewage sludge as renewable resources are urged to be used in agriculture, but their reuse poses potential chemical and microbiological risks. As a waste biomass resource, sludge combined with reclaimed water irrigation is a major way to develop and utilize renewable resources and control environmental pollution. However, whether reclaimed water irrigation and sludge application have adverse effects on the agricultural environment and human health remains a controversial point of discussion. A greenhouse pot experiment was conducted to investigate the effects of reclaimed water and sewage sludge on rhizosphere soil and root endophytic bacterial communities, the abundance of selected genes, and to evaluate the soil quality of sludge application. The results of this study demonstrated that the application of sewage sludge could result in the accumulation of nutrients in soil. The rhizosphere soil and root endophytic bacteria possessed common dominant groups at phylum level, including Proteobacteria, Bacteroidota, Actinobacteriota and Chloroflexi. Reclaimed water irrigation had less effect on rhizosphere soil and root endophytic bacterial communities than sludge application. Pseudomonas showed a decrease in relative abundance in both rhizosphere soil and root endophytes following sludge application, whereas beneficial bacteria like Bacillus, Stenotrophobacter, Cellvibrio and Altererythrobacter experienced an increase. Redundancy analysis (RDA) showed that the diversity and composition of bacterial communities in rhizosphere soil among treatment groups were closely related to soil organic matter, total nitrogen and total phosphate contents. The functional prediction highlighted the participation of functional groups in nitrogen and carbon cycling as well as degradation processes at varying sludge application rates. The abundance of selected genes was more affected by sludge application. A considerable amount of sludge application to the soil resulted in a significant increase in the abundance of pathogens and antibiotic resistance genes, as well as functional genes, compared to unamended soil with sludge treatment. Direct or excessive application of sludge might aggravate the dissemination and accumulation of deleterious genes in soil-crop systems irrigated with reclaimed water. Overall, our study results may provide valuable information on how sludge influences the microbial community characteristics and abundance of specific genes, guiding the assessment of biological quality and the appropriate use of sludge in agriculture irrigated with reclaimed water.

The occurrence, concentration, spatial distribution, seasonal variations, and ecotoxicological risks of six typical UV filter and insect repellent personal care products (PCPs) were evaluated in multiple environmental matrices (river/estuary/wetland water, seawater, beach sands, local WWTP water and sludges) in a coastal resort area in Qingdao, China. Target PCPs were widely detected, with significantly higher levels in the summer across all matrices. Insect repellents (max = 841.49 ng/L for diethyltoluamide [DEET]) were typically found in higher concentrations in natural waters than UV filters (max = 356.24 ng/L for octocrylene [OC]), with oxybenzone (BP3) present in trace levels (generally below 1 ng/L). Seawater exhibited low-level PCPs (mostly below 100 ng/L in total), while high concentrations found in several estuaries suggest potential direct input of relevant PCPs. All target PCPs were present in beach sands (below 50 ng/g dry weight for individual PCP). Natural/constructed wetlands showed minimal removal effects. Insect repellents, particularly DEET (13.97-919.69 ng/L), were abundant in wastewater treatment plant (WWTP) influents, while OC levels were high in sludges (max = 3842.44 ng/g dry weight). Secondary biological treatment substantially removed PCPs despite increases in the primary aerated grit tank. Significant correlations (p < 0.05) were found between various matrices, such as sands and adjacent seawater for OC, and WWTP water and sludge for 2-ethylhexyl 4-methoxycinnamate (EHMC). Ecotoxicological risk assessments revealed no-to-medium risks at most sites for individual PCPs, with higher risks in the summer; during this period, river/estuary waters demonstrated higher total risks than seawater, with beach-adjacent seawater showing elevated risks, and several estuaries showed greater risks than their upper reaches. The findings underscore the necessity for research on UV filter and insect repellent PCPs and their associated risks in coastal resort areas.

Farmland ammonia (NH3) volatilization is an important source of NH3, and the application of chemical fertilizer nitrogen (N) is the main factor affecting NH3 volatilization. The optimal substitution of chemical fertilizer with organic manure and straw reportedly reduces NH3 volatilization, while reducing irrigation increases NH3 volatilization. However, the combined effect of nitrogen fertilizer substitution and reducing irrigation on NH3 volatilization and the role of microorganisms in this process remains unclear. In a soil column experiment, NH3 volatilization and microbial composition were measured under both multiple N sources and different irrigation levels by the vented-chamber method and metagenomic sequencing. The results revealed that multiple N sources application reduced cumulative NH3 volatilization by 16.5–75.4% compared to single chemical fertilizer application, and the decreasing trend of NH3 volatilization under reduced irrigation conditions was greater. Microorganisms had a more important effect on NH3 volatilization of reduced irrigation than conventional irrigation. The abundance of nirA, arcC, E3.5.1.49, and E3.5.5.1 (ammonia-producing) genes varied significantly at the two irrigation levels. Overall, multiple N sources could inhibit NH3 volatilization increasing under reducing irrigation compared to a single chemical fertilizer. Our findings contribute valuable insights into the combined effect of reduced irrigation and multiple N sources on NH3 volatilization.

Biochar amendment is a promising strategy for mitigating antibiotic resistance genes (ARGs) in soil and plants, but its effects on ARGs at field scale are not fully understood. Here, field trials were executed utilizing two plant varieties, Brassica juncea and Lolium multiflorum, with four types of biochar to investigate changes in ARGs and microbiome in soil, rhizosphere, root endophytes, and leaf endophytes. Results showed that biochar altered ARG distribution in soil and plant, and restrained their transmission from soil and rhizosphere to endophytes. A reduction of 1.2-2.2 orders of magnitude in the quantity of ARGs was observed in root and leaf endophytes following biochar addition, while no significant changes were observed in soil and rhizosphere samples. Procrustes and network analyses revealed significant correlations between microbial communities and mobile genetic elements with ARGs (P < 0.05). Besides, redundancy and variation partitioning analysis indicated that bacterial communities may play a dominant role in shaping the ARGs profile, contributing to 43 % of the variation observed in ARGs. These field results suggest that biochar amendment alone may not fully alleviate ARGs in soil, but it has a significant beneficial impact on food safety and human health by effectively reducing ARGs in plant endophytes.

High-risk antibiotic resistance genes (ARGs) in reclaimed water-irrigated soil pose a potential threat to ecosystem and human health. Inorganic fertilization – including with nitrogen, a key ingredient in agricultural production – may affect the ARG profile in soil. However, little is known about nitrogen fertilization's influence on ARGs profiles in the soil–plant system. This study investigated the effects of different nitrogen fertilizer types (CO(NH2)2, NO3–-N (NaNO3) and NH4+-N (NH4HCO3)) and different nitrogen fertilizer application rates (low, medium, high) on the distribution of high-risk ARGs in reclaimed water-irrigated soil and plants using quantitative PCR, high-throughput sequencing and metagenomic sequencing. Soil microcosms results revealed that nitrogen fertilization significantly affected the pattern of high-risk ARGs in soil, and also affected high-risk ARGs abundance and transfer capacity in plants. Compared with nitrogen fertilizer application rate, nitrogen fertilizer types significantly contributed to enhancing the soil resistome, with the order of CO(NH2)2 > NO3–-N ≈ NH4+-N. The medium application of NO3–-N and NH4+-N significantly reduced high-risk ARGs abundance in the leaf endophyte. Bacterial community mainly drove the variation of ARGs in nitrogen-fertilized soil–plant system, and class I integron and metal resistance genes (MRGs) also had direct effects on these high-risk ARGs. A similar high-risk ARGs pattern was also found in field plot experiments, and several dangerous pathogens were observed as the main high-risk ARGs potential hosts in nitrogen-fertilized soil. Based on an economic assessment, application of NH4+-N (NH4HCO3) could reduce costs by $1,312.83 ha−1 compared with NO3–-N (NaNO3). These results showed that the more important role of nitrogen type might be an effective and economical way to control high-risk ARGs spread in soil–plant system under reclaimed water irrigation.

High frequent detection of sulfamethoxazole (SMX) in wastewater cannot be effectively removed by constructed wetlands (CWs) with a traditional river sand substrate. The role of emerging substrate of hematite in promoting SMX removal and the effect of influent SMX loads remain unclear. The removal efficiency of SMX in hematite CWs was significantly higher than that in river sand CWs by 12.7-13.8% by improving substrate adsorption capacity, plant uptake and microbial degradation. With increasing influent SMX load, the removal efficiency of SMX in hematite CWs slightly increased, and the removal pathways varied significantly. The contribution of plant uptake was relatively small (< 0.1%) under different influent SMX loads. Substrate adsorption (37.8%) primarily contributed to SMX removal in hematite CWs treated with low-influent SMX. Higher influent SMX loads decreased the contribution of substrate adsorption, and microbial degradation (67.0%) became the main removal pathway. Metagenomic analyses revealed that the rising influent load increased the abundance of SMXdegrading relative bacteria and the activity of key enzymes. Moreover, the abundance of high-risk ARGs and sulfonamide resistance genes in hematite CWs did not increase with the increasing influent load. This study elucidates the potential improvements in CWs with hematite introduction under different influent SMX loads.

Agricultural utilization of reclaimed water is considered to be an effective way to solve water shortage and reduce water environmental pollution. Silicon fertilizer can improve crop yield and quality and enhance crop resistance. The effect of foliar spray with silicon fertilizer on phyllosphere microbial communities remains lacking. In this study, a pot experiment was conducted to explore the effects of different types of silicon fertilizer on the composition and diversity of a phyllosphere bacterial community and the abundances of related functional genes in rice irrigated with reclaimed water. The results showed that Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidota, and Verrucomicrobiota dominated the phyllosphere bacteria of rice. The relative abundance of Bacillus was higher than that of other treatments in RIS3. Reclaimed water irrigation significantly increased the relative abundances of the potential pathogens Pantoea and Enterobacter. The unclassified bacteria were also an important part of the bacterial community in the rice phyllosphere. Bacillus, Exiguobacterium, Aeromonas, and Citrobacter were significantly enriched by silicon fertilizer treatments. Functional prediction analysis showed that indicator species were mainly involved in metabolism and degradation functions, and the predicted functional groups of phyllosphere bacteria were attributed to chemoheterotrophy, aerobic chemoheterotrophy, nitrate reduction, and fermentation. Quantitative PCR results showed that AOA, AOB, and nifH genes were at low abundance levels in all treatments, and nirK genes was not significantly different among treatments. These results contribute to the in-depth understanding of the effects of foliar spray silicon fertilizer on the bacterial community structure and diversity of rice phyllosphere and provide a theoretical basis for the application of silicon fertilizer in reclaimed water irrigation agriculture.

The deep migration of soil nitrogen (N) poses a significant risk of N leaching, contributing to non-point-source pollution. This study examines the influence of microbial networks on the deep migration of chemical fertilizer N under varying irrigation management and multiple N fertilizer sources. A soil column experiment with eight treatments was conducted, utilizing 15N isotope labeling and metagenomic sequencing technology. The findings revealed that reduced irrigation significantly curbs the deep migration of chemical fertilizer N, and straw returning also mitigates this migration under conventional irrigation. Microbial network complexity and stability were markedly higher under reduced irrigation compared to conventional practices. Notably, network node count, average degree, and modularity exhibited significant negative correlations with the deep migration of chemical fertilizer N. The network topology indices, including node count, average clustering coefficient, average degree, modularity, and edge count, were found to be relatively more important for the deep migration of chemical fertilizer N. In conclusion, microbial networks play an important role in reducing the deep migration of chemical fertilizer N.

【Objective】 Constructed wetland is a biotechnological technique to treat wastewater; its function depends on a multitude of biotic and abiotic factors. This paper compares the performance of eight wetlands constructed by different materials. 【Method】 The eight wetlands we studied were constructed by fine sand only (CK), fine sand + corn straw powder (JW), fine sand + industry glucose (PW), sand + corn-straw biochar (SW), fine sand + eisenia fetida (KQ), fine sand + corn straw powder + eisenia fetida (JQ), fine sand + industrial glucose + eisenia fetida (PQ), fine sand + corn stover biochar + eisenia fetida (SQ), respectively. 【Result】 Adding corn-straw biochar, industrial glucose and corn-straw power increased the COD removal rate by 81.80%, 88.58% and 85.77%, respectively, compared to CK. Adding industrial glucose combined with corn straw powder improved purification efficiency of total N (TN) and total P (TP) by 7.0% and 2.8%, respectively. Wetland with industrial glucose and corn straw powder had the best TN removal rate, reaching 98% and 98.2%, respectively. Adding corn-straw power along with eisenia fetida was most effective to remove cooper, compared with other treatments. On average, introducing eisenia fetida to the wetlands increased the removal rates of COD, Cu and Zn by 1.8%, 6.3% and 2.6%, respectively, while adding corn-stover biochar significantly increased the removal rate of NH4+-N. Compared with corn straw powder and corn straw biochar, industrial glucose was more efficient for removing COD, total N and N, and Cu. 【Conclusion】 Adding eisenia fetida and organic carbon to the wetland can improve its efficacy to remove COD, nitrogen and heavy metals, especially corn-stover powder combined with eisenia fetida. For removing Cu, corn straw powder combined with eisenia fetida works the best.

Environmental hazards and remediation of pharmaceuticals and personal care products（PPCPs）have recently received growing attentions. Thus, investigating the purification effect of azolla on domestic sewage containing PPCPs is important. Representative PPCPs gemfibrozil, carbamazepine, and azolla were used as test materials, and indoor simulation culture tests were conducted to investigate the growth of azolla in domestic wastewater at both different incubation times（1, 2, 4, and 8 d）and different initial concentrations of PPCPs(0,1, 10, 100, and 1 000 μg·L -1 ), as well as the removal rates of conventional pollutants（ammonia nitrogen, NH3-N; nitrate nitrogen, NO 3 --N;total phosphorus, TP; chemical oxygen demand, COD）and PPCPs. With an increase of the initial concentration of PPCPs in domestic wastewater, the relative growth rate and tolerance index of azolla showed a trend of first increasing and then decreasing, and the growth of azolla was inhibited under the treatment of 100 and 1 000 μg · L -1 PPCPs. Compared with the control, the removal effect of azolla on nitrogen and phosphorus was significantly enhanced under 1 and 10 μg·L -1 PPCPs treatment（P＜0.05）, but was significantly weakened under100 and 1 000 μg·L -1 PPCPs treatment（P＜0.05）. When treating with different initial concentrations of PPCPs, the effect of azolla on COD removal was significant, and the COD removal rate increased with the increase of the initial concentration of PPCPs. The removal effect of azolla on gemfibrozil and carbamazepine was enhanced with increasing incubation time. The removal rate of gemfibrozil increased with increasing initial concentration of PPCPs(except for 1 000 μg·L -1 PPCPs treatment), whereas the removal rate of carbamazepine decreased with increasing initial concentration of PPCPs. Azolla has a good removal effect on both PPCPs and conventional pollutants other than ammonia nitrogen in domestic wastewater and can be used as a remediation treatment plan for domestic wastewater containing typical PPCPs.

The transfer of antibiotic resistance genes (ARGs) in soil under reclaimed water irrigation poses a potential environmental risk. Regulation of NPK fertilizer could influence the behavior of bacterial communities, mobile genetic elements (MGEs), and soil properties, which determine the fate of ARGs. To identify the key element in NPK fertilizer and realize efficient regulation, we explored the effect of individual N, P, K fertilization on ARG variation in tomato rhizosphere and bulk soils. Compared with an unfertilized treatment, N fertilization resulted in greater decreases in the abundance of ARGs (decreases of 24.06%-73.09%) than did either P fertilization (increases of up to 35.84%, decreases of up to 58.80%) or K fertilization (decreases of 13.47%-72.47%). The influence of different forms of N (CO(NH2)2, NaNO3, and NH4HCO3), P (Ca(H2PO4)2 and CaMgO4P+), and K (KCl and K2(SO4)) fertilizers was also investigated in this study, and showed the influence of NaNO3, CaMgO4P+, and K2(SO4) on reducing ARGs abundance was greater in different types of N, P, K fertilizers. Bacterial communities showed the strongest response to N fertilization. The reduced bacterial diversity and abundance of ARG-host and non-host organisms explained the decline of total ARG abundance in soil. In soils fertilized with either P or K, the effect of soil properties, especially total nitrogen and pH, on ARG variation was greater than that of bacterial community and MGEs. These results suggest that N regulation of in NPK fertilizer may be an effective way to reduce the risks of ARGs in soil associated with reclaimed water irrigation.

【Background】 Selenium is a crop nutrient but scarce in many soils. One solution is to add selenium with irrigation water to the soil. In this paper we investigated experimentally spatial accumulation and distribution of added selenium and is correlation with physical and chemical properties of soil under different irrigations using reclaimed water. 【Method】 The experiment was conducted in pots. It consisted of two selenium additions: 4 mg/kg and 1 mg/kg (L), with each addition having three irrigation amounts (or methods). 2 L/h drip irrigation (2D), 4 L/h drip irrigation (4D), and border irrigation (S). Without selenium addition was taken as the control (CK). We measured accumulation and distribution of the added selenium in each pot. 【Result】 Except in CK, selenium content in the top 0~10 cm soil was significantly higher than that in the 10~20 cm soil (P<0.05). For L treatment, the selenium content in the soil 10 cm away from the emitter under 2D, 4D and S increased by 1.04, 1.21 and 0.83, respectively, while for H treatment these increased by 2.03, 2.31 and 2.48 times, respectively, compared to CK. The contour of selenium content in 2D+L and 2D+H showed a "narrow-deep" type, while in 4D+L and 4D+H and Q+L, it showed a “pudgy” type. Selenium content in Q+H showed a “near horizontal contour” distribution. 【Conclusion】 Adding selenium with irrigation water increased selenium content in the 0~10 cm soil, with the content increasing with the application amount. Compared with border irrigation, drip irrigation increased selenium accumulation in the root zone - the top 0~10 cm of soil. Soil selenium content was positively correlated with organic matter and water content in the 0~10 cm soil, but negatively correlated to soil conductivity, both at significant levels.

Due to reclaimed water, irrigation can cause human health and environmental risks. Soil amendments are applied to reveal the abundance of pathogens and antibiotic resistance genes in rhizosphere soil irrigated by reclaimed water and to better understand the effects of environmental factors on the rhizosphere soil bacterial composition, which has guiding significance for the reasonable use of soil amendments. In this study, the effects of biochar, bioorganic fertilizer, humic acid, loosening soil essence, and corn vinasse on bacterial community diversity and certain gene abundances in rhizosphere soil under drip irrigation with reclaimed water were studied using high-throughput assays and quantitative PCR. The results showed that biochar significantly increased pH, organic matter, and total nitrogen contents in the rhizosphere soil. The corn vinasse significantly decreased soil pH and increased the contents of total nitrogen and total phosphorus but significantly increased the soil EC value (P<0.05). The effects of the five soil amendments on the α-diversity of rhizosphere bacteria were not significantly different. The bacterial community structure and diversity of rhizosphere bacteria were similar at different taxonomic levels, but their relative abundance was different. α-Proteobacteria, γ-Proteobacteria, Bacteroidia, Actinobacteria, Acidimicrobiia, and Anaerolineae were the dominant bacteria in all treatments. The dominant genera consisted of Pseudomonas, Sphingobium, Sphingomonas, Cellvibrio, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Flavobacterium, and Algoriphagus (relative abundance>1%). Correlation analysis of environmental factors showed that the composition of the rhizosphere bacterial community was strongly correlated with pH, EC, total nitrogen, and total phosphorus content. The abundances of pathogenic bacteria and antibiotic resistance genes were 103-107 copies·g-1 and 104-108 copies·g-1, respectively. There were significant differences in the detection levels of pathogens and antibiotic resistance genes. Bioorganic fertilizer, loosening soil essence, and corn vinasse significantly increased the abundances of some antibiotic resistance genes, whereas humic acid and corn vinasse significantly decreased the abundances of Pseudomonas syringae, Ralstonia solanacearum, and total coliforms (P<0.05). A significant correlation was found between pathogens (Arcobacter, Bacillus cereus, Pantoea agglomerans, and Fecal bacteroidetes) and antibiotic resistance genes (tetA, tetB, tetO, tetQ, sul1, ermB, and ermC). In conclusion, while monitoring pathogens and antibiotic resistance genes in the agricultural environment under reclaimed water irrigation, attention should be paid to the rational application of soil amendments to avoid exacerbating the spread of biological contamination.

Antibiotics and corresponding antibiotic resistance genes (ARGs) are emerging pollutants in wastewater that pose a significant threat to the environment and human health. Constructed wetlands (CWs) are a cost-effective technology for eliminating these pollutants through substrates, plants, and microorganisms. Detailed reviews of the roles of CW substrates on antibiotic and ARG removal and recent progress in the field are lacking. This paper reviews the mechanisms influencing antibiotic and ARG (intracellular and extracellular) removal in CWs, and natural, biomass, chemical, modified, industrial, novel, and combined substrates on their removal efficiencies. Generally, substrates remove antibiotics and ARGs mainly through adsorption, biodegradation, chemical oxidation, and filtration. Other mechanisms, such as photolysis, may also contribute to removal. Natural substrates (e.g., gravel, zeolite) are more frequently employed than other types of substrates. The removal performance of antibiotics and intracellular ARGs by zeolite was better than that of gravel through enhanced substrate adsorption, filtration, and biodegradation processes. Moreover, Mn ore showed promising high capability to remove high concentration of antibiotics through various removal pathways. In addition, combined substrates of soil/sand/gravel and other substrates further facilitate antibiotic removal. Future research is suggested to explore the mechanisms of competitive adsorption and redox-controlled biodegradation, investigate the effect of Fe/Mn oxides on the removal of antibiotics and ARGs via chemical oxidation, evaluate the removal of extracellular ARGs by CWs with different substrates, and investigate the effect of substrates on removal of antibiotics and ARGs in full-scale CWs.

随着药品和个人护理品(Pharmaceuticals and Personal Care Products,PPCPs)生产和使用量的增加,PPCPs及其代谢产物在再生水中的检出种类、检出量不断增多,再生水灌溉可影响PPCPs在土壤-作物(蔬菜)系统中的分布及累积,但其规律及驱动机制尚不明确.为探明再生水滴灌条件下滴头布置方式对PPCPs在土壤-作物(蔬菜)系统累积的影响,该研究采用盆栽试验比较2种滴头布置方式(在番茄根部、在两番茄中间)对土壤剖面及番茄各器官中PPCPs累积量的影响,并进一步分析PPCPs在土壤-作物(蔬菜)系统累积的驱动机制.结果表明,再生水灌溉条件下不同滴头布置方式造成了PPCPs在土壤、作物(蔬菜)中累积规律的差异性,滴头布置在两番茄中间处理较其他处理而言增加了0～5 cm土层吉非罗齐累积量(P<0.05),降低了番茄叶部卡马西平和根部吉非罗齐的累积量(P<0.05),较滴头布置在番茄根部处理降低了番茄叶部吉非罗齐和根部三氯生的累积量(P<0.05);不同再生水灌溉方式通过影响土壤微环境指标导致了土壤中PPCPs分布规律的差异性,滴头布置在植株中间处理较其他处理增加了0～5 cm土层pH值,导致该土层下吉非罗齐的累积量高于其他处理(P<0.05).研究可为基于新兴污染物PPCPs防控的再生水农业安全利用提供理论依据.

随着药品和个人护理品(PPCPs)生产和使用量的增加,PPCPs及其代谢产物在水体、土壤环境中的检出量、检出种类与日俱增.本文基于国内外已有的相关文献,总结了典型PPCPs通过不同途径进入土壤-作物系统的环境风险,并从PPCPs在土壤-作物系统中的降解行为特征和迁移累积规律等方面对PPCPs环境行为及归趋的最新研究进展进行了综述,指出目前研究存在的PPCPs种类、浓度、输入方式以及环境背景的单一性等突出问题,并对该领域未来研究趋势进行了展望,如不同类别PPCPs的环境行为特征、与土壤微环境的互作机制、降解或螯合产物及其环境行为与风险等方面的研究,对于探明PPCPs对生态环境的影响规律及对人类健康的潜在危害具有重要意义.

为了探讨淡水资源匮乏地区微咸水与再生水的安全合理利用，通过盆栽上海青试验，以清水灌溉为对照，设置再生水灌溉（T1）、微咸水—再生水1∶2灌溉（T2）、微咸水—再生水1∶1灌溉（T3）、微咸水灌溉（T4）4种灌溉方式，研究了不同比例微咸水与再生水混合灌溉对土壤水盐、作物生物量（地上部和地下部）、叶片叶绿素含量、可溶性蛋白含量、丙二醛（MDA）含量、过氧化氢酶（CAT）活性、超氧化物歧化酶（SOD）活性、过氧化物酶（POD）活性的影响。结果表明：（1）上海青收获后，不同比例微咸水与再生水混合灌溉处理土壤含水率和含盐量较清水灌溉（CK）均有所升高，其中T1、T2、T3处理土壤含水率与CK差异不显著，T4处理土壤含水率较CK差异显著（P<0.05），而各处理土壤含盐量与CK均差异显著；与T1处理相比，随着灌溉水中微咸水比重的升高，土壤含水率逐渐升高，且至T4处理时差异显著。（2）微咸水与再生水混灌对上海青地上部鲜重有一定影响，而对地上部干重以及地下部生物量无显著影响。与T1相比，T2、T3、T4处理上海青地上部鲜重均显著降低（P<0.05），降幅为24.78%~26.36%，地上部干重亦均降低，但差异不显著，降幅为19.14%~24.54%，地下部鲜重和干重无显著性变化。（3）微咸水与再生水混灌对上海青生理指标（叶绿素含量、可溶性蛋白含量、MDA含量、POD活性、CAT活性）没有显著影响，对SOD活性具有显著的提升作用。与T1相比，T2、T3、T4处理叶绿素a含量分别降低4.98%，3.82%和9.26%，叶绿素b含量分别降低10.88%，8.20%和13.46%，叶绿素总量分别降低9.76%，6.12%和10.15%，CAT活性分别提高8.51%，8.51%和-19.15%，POD活性分别提高1.92%，17.24%和-2.87%，SOD活性分别提高104.07%，62.20%和41.67%。随着混合液中微咸水比重的升高，上海青可溶性蛋白含量先降低后升高，MDA含量先升高后降低。（4）基于第二代综合生物响应指数（integrated biological response version 2，IBRv2），综合考虑土壤水盐、作物生理指标以及再生水资源本身的局限性，在淡水资源匮乏地区利用微咸水灌溉时，可以考虑用再生水作为替代清水水源与微咸水配合使用，微咸水—再生水混灌比例以1∶1为宜。研究结果可为淡水不足地区利用微咸水（3 g/L）灌溉提供参考。

硅(Si)元素被认为是N、P、K之后的第四大元素.硅肥有利于促进作物的生长和土壤环境的改善.为了给硅肥利用的研究提供一定参考,通过文献综述的方法,总结了逆境条件下硅肥对低温胁迫的调控作用、对植株病害的防效、对水分胁迫的调控作用以及对重金属胁迫的缓解效应.综合现有研究结果,认为增施硅肥具有提高植株的耐盐胁迫、耐重金属胁迫、抗低温、抗病害等能力.此外,不同硅肥的调控效果不同,而且配施其他肥料或者农艺措施等效果更佳.最后,对今后硅肥利用研究方面提出一些建议:(1)加强硅肥的相关机理研究,如硅是如何改善土壤微环境的,纳米硅材料在植物体内的运输、积累及其对植物抗逆性能的作用机理研究;(2)开展硅肥与非常规水资源安全利用的耦合研究,如何利用硅肥的特性来解决微咸水灌溉和再生水灌溉及其二者耦合灌溉的问题;(3)加强硅肥的提质效应研究.