Ecological Risk Management Research Articles

The utility of joinpoint regression for estimating population parameters given changes in population structure

The method of joinpoint regression has been used in numerous domains to assess changes in time series data, including such things as cancer mortality rates, motor vehicle collision mortalities, and disease risk. To help improve estimation of population parameters for use in ecological risk assessment and management, we present a simulation and analysis to describe the utility of this method for the ecological domain. We demonstrate how joinpoint regression can accurately identify if the population structure changes based on time series of abundance, as well as identify when this change occurs. In addition, we compare and contrast population parameter estimates derived through joinpoint and surplus production methods to those derived from standard surplus production methods alone. When considering a change point at 32 years (out of a 64 year simulation), the joinpoint regression model was able, on average, to estimate a joinpoint time of 32.31 years with a variance of 6.82 and 95% confidence interval for the mean relative bias of (0.0085, 0.0112). The model was able to consistently estimate population parameters, with variance of these estimations decreasing as the change in these population parameters increased. We conclude that joinpoint regression be added to the list of methods employed by those who assess ecological risk to allow for a more accurate and complete understanding of population dynamics.

Impacts of Shenzhen basic ecological control line on landscape ecological risk

The Shenzhen Basic Ecological Control Line (SZBECL) has been in operation for more than ten years since its implementation in 2005, which has a significant protective effect on the ecological space. Landscape ecological risk refers to the possible adverse consequences caused by the natural or human-induced interactions between landscape pattern and ecological processes. The scien-tific management of ecological risk is an important prerequisite for the sustainable development of human beings. Therefore, it is of great significance to explore the changes of landscape ecological risk inside and outside the SZBECL. Combining two indicators (ecological sensitivity and landscape vulnerability), we comprehensively evaluated the landscape ecological risk of Shenzhen in 2005 and 2015. The difference-in-difference method was used to explore the impacts of the SZBECL on the landscape ecological risk inside the line. Results showed that the landscape ecological risk in Shen-zhen presented a spatial structure of "high west and low east", which decreased by 13.5% during 2005 to 2015. Inside and outside the SZBECL, the declines of the landscape ecological risk were 0.7% and 14.4%, respectively. For the five subzones, declines were more significant outside the SZBECL, except for the eastern coastal zone. After controlling the effects of other variables, at the municipal level, there was 1.8% higher landscape ecological risk inside the line compared with the region outside the line. Furthermore, at the subzone level, there was 1.6%, 1.6%, 1.4%, and 1.9% higher landscape ecological risk inside the line in the central urban zone, the western coastal zone, the middle zone, and the eastern zone, respectively. There was no significant difference between the inside and outside of the line in the eastern coastal zone. With the implementation of SZBECL, habitat quality and landscape vulnerability inside the line were lowered, but NDVI and population density did not change.

Urban-rural gradients of polycyclic aromatic hydrocarbons in soils at a regional scale: Quantification and prediction

The quantitative study of urban-rural gradients for persistent organic pollutants (POPs) is extremely important to understand the behavior of POPs as well as for ecological risk assessment and management. In this study, a practical urban-rural gradient model (URGM) was developed using atmospheric point source diffusion combined with a fugacity approach to test potential mathematical relationships among urban and rural soils. The mean value of polycyclic aromatic hydrocarbons (PAHs) for urban soils (0–2-km sites) was 570.80 ng/g, and was approximately 3.5 times higher than rural soils (30–50 km sites). Significant linear correlations were found between the amounts of PAHs in the surface soil and the city population and between the soil concentration and artificial surface area. Urban-rural PAH concentrations were simulated by the URGM and calibrated by city population and land-cover data, with average relative errors of 12.84%. The results showed that the URGM was suitable for simulating urban-rural PAH concentrations at a regional scale. The combustion of fossil fuels, biomass, and coal was the main source of soil PAHs in the study area, and the characteristic ratios of PAHs indicated a transition trend from pyrogenic to petrogenic sources along the urban-rural transects. This study thus provides a combined method for quantifying urban-rural gradients of PAHs and can thereby promote quantitative research on coupling among land cover, socio-economic data, and POP concentrations.

Ecological and human health risk assessment.

The literature review presented in this paper covers the risk assessment process that is important to human health as well as the health of ecology in the form of receptors. One of the important objectives of present review is to provide summary of the scientific studies published in the year 2018. The review starts with literature published on the assessment of health risks, which are valuable to human and ecology. Most of the literature in the entire article focuses on techniques used for the analysis of scientific data and methods. In addition, review also highlights data interpretation, uncertainty, policy, and regulatory guidance associated with the management of human and ecological risks. Particularly, the review on the risk assessment related to human health and ecology is divided into two main sections. These sections provide broad state of knowledge on the risk assessment process used to health of human and ecological systems focused on investigation of polluted sites, techniques of remediation, and tools required for natural resource management.

Predicting the acute ecotoxicity of chemical substances by machine learning using graph theory

Accurate in silico predictions of chemical substance ecotoxicity has become an important issue in recent years. Most conventional methods, such as the Ecological Structure-Activity Relationship (ECOSAR) model, cluster chemical substances empirically based on structural information and then predict toxicity by employing a log P linear regression model. Due to empirical classification, the prediction accuracy does not improve even if new ecotoxicity test data are added. In addition, most of the conventional methods are not appropriate for predicting the ecotoxicity on inorganic and/or ionized compounds. Furthermore, a user faces difficulty in handling multiple Quantitative Structure-Activity Relationship (QSAR) formulas with one chemical substance. To overcome the flaws of the conventional methods, in this study a new method was developed that applied unsupervised machine learning and graph theory to predict acute ecotoxicity. The proposed machine learning technique is based on the large AIST-MeRAM ecotoxicity test dataset, a software program developed by the National Institute of Advanced Industry Science and Technology for Multi-purpose Ecological Risk Assessment and Management, and the Molecular ACCess System (MACCS) keys that vectorize a chemical structure to 166-bit binary information. The acute toxicity of fish, daphnids, and algae can be predicted with good accuracy, without requiring log P and linear regression models in existing methods. Results from the new method were cross-validated and compared with ECOSAR predictions and show that the new method provides better accuracy for a wider range of chemical substances, including inorganic and ionized compounds.

Overcoming Challenges of Incorporating Higher Tier Data in Ecological Risk Assessments and Risk Management of Pesticides in the United States: Findings and Recommendations from the 2017 Workshop on Regulation and Innovation in Agriculture.

ABSTRACTPesticide regulation requires regulatory authorities to assess the potential ecological risk of pesticides submitted for registration, and most risk assessment schemes use a tiered testing and assessment approach. Standardized ecotoxicity tests, environmental fate studies, and exposure models are used at lower tiers and follow well‐defined methods for assessing risk. If a lower tier assessment indicates that the pesticide may pose an ecological risk, higher tier studies using more environmentally realistic conditions or assumptions can be performed to refine the risk assessment and inform risk management options. However, there is limited guidance in the United States on options to refine an assessment and how the data will be incorporated into the risk assessment and risk management processes. To overcome challenges to incorporation of higher tier data into ecological risk assessments and risk management of pesticides, a workshop was held in Raleigh, North Carolina. Attendees included representatives from the United States Environmental Protection Agency, United States Department of Agriculture, National Oceanic and Atmospheric Administration, universities, commodity groups, consultants, nonprofit organizations, and the crop protection industry. Key recommendations emphasized the need for 1) more effective, timely, open communication among registrants, risk assessors, and risk managers earlier in the registration process to identify specific protection goals, address areas of potential concern where higher tier studies or assessments may be required, and if a higher tier study is necessary that there is agreement on study design; 2) minimizing the complexity of study designs while retaining high value to the risk assessment and risk management process; 3) greater transparency regarding critical factors utilized in risk management decisions with clearly defined protection goals that are operational; and 4) retrospective analyses of success–failure learnings on the acceptability of higher tier studies to help inform registrants on how to improve the application of such studies to risk assessments and the risk management process. Integr Environ Assess Manag 2019;15:714–725. © 2019 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

A Quantitative Assessment of Comprehensive Ecological Risk for a Loess Erosion Gully: A Case Study of Dujiashi Gully, Northern Shaanxi Province, China

As a tool that can effectively support ecosystem management, ecological risk assessment is closely related to the sustainable development of ecosystems and human well-being and has become an active area of research in ecology, geography and other disciplines. Taking Dujiashi Gully for the study of gully loess erosion, a comprehensive risk assessment system for identifying risk probability, sensitivity and impairment was established. The spatial distribution of comprehensive ecological risk was analyzed, the ecological risk management categories were simultaneously delineated based on the risk dominant factor and the risk management strategies were formulated in loess regions. The results were as follows: (1) the spatial differences in comprehensive ecological risk were significantly different in the research area. The regions with extremely high and high risk were mainly located in gully areas and secondary erosion gullies, which are in 28.02% of study area. The extremely low-risk areas covered 1/3 of the study area and were mainly distributed to the northwest and south of the study area, where hills are widely spaced. (2) The combined analysis of ecological risk and terrain found that the elevation decreased first and then rose but the comprehensive ecological risk increased first and then decreased from north to south. Comprehensive ecological risk and terrain generally showed an inverse relationship. (3) The study area was divided into four types of risk management categories. Risk monitoring zones, habitat recovery zones, monitoring and recovery zones and natural regulation zones encompass 14.84%, 12.44%, 26.47% and 46.25% of the study area, respectively. According to four types of risk management categories, different risk reduction measures were designed to improve regional sustainable development capacity. Risk identification and risk management categories based on comprehensive ecological risk model can design a sustainable development path for social ecosystem and local farmers and provide a method for sustainable development for similar gully landscapes.

Assessment and management of urbanization-induced ecological risks

ABSTRACTThe urban ecological risk incurred during the processes of urbanization has been constantly accumulating, creating a severe challenge for China to achieve sustainable urban development. At present, research on systematic evaluation of urban ecological risks is still inadequate, especially at an urban ecosystem level. In this special issue, we use Xiamen City as an example to identify the sources and receptors of urban ecological risks, to develop a methodology system of urban ecological risk assessment, and to propose a method for the management of urban ecological risks. This special issue contains 11 research articles resulting from a comprehensive research project funded by China’s National Natural Science Foundation. The innovations reported in this special issue include a framework of urban ecological risk assessment and a standardized procedure for carrying out urban ecological risk assessment using multiple stressors and endpoints.

Seasonal dynamics of tetracycline resistance gene transport in the Sumas River agricultural watershed of British Columbia, Canada

Environmental transport of contaminants that can influence the development of antibiotic resistance in bacteria is an important concern in the management of ecological and human health risks. Agricultural regions are locales where practices linked to food crop and livestock production can introduce contaminants that could alter the selective pressures for the development of antibiotic resistance in microbiota. This is important in regions where the use of animal manure or municipal biosolids as waste and/or fertilizer could influence selection for antibiotic resistance in pathogenic bacterial species. To investigate the environmental transport of contaminants that could lead to the development of antibiotic resistance in bacteria, a watershed with one of the highest levels of intensity of agricultural activity in Canada was studied; the Sumas River located 60 km east of Vancouver, British Columbia. This two-year assessment monitored four selected tetracycline resistance genes (tet(O), tet(M), tet(Q), tet(W)) and water quality parameters (temperature, specific conductivity, turbidity, suspended solids, nitrate, phosphate and chloride) at eight locations across the watershed. The tetracycline resistance genes (Tcr) abundances in the Sumas River network ranged between 1.47 × 102 and 3.49 × 104 copies/mL and ranged between 2.3 and 6.9 copies/mL in a control stream (located far from agricultural activities) for the duration of the study. Further, Tcr abundances that were detected in the wet season months ranged between 1.3 × 103 and 2.29 × 104 copies/mL compared with dry season months (ranging between 0.6 and 31.2 copies/mL). Highest transport rates between 1.67 × 1011 and 1.16 × 1012 copies/s were observed in November 2005 during periods of high rainfall. The study showed that elevated concentrations of antibiotic resistance genes in the order of 102–104 copies/mL can move through stream networks in an agricultural watershed but seasonal variations strongly influenced specific transport patterns of these genes.

Insights into the Toxicity of Triclosan to Green Microalga Chlorococcum sp. Using Synchrotron-Based Fourier Transform Infrared Spectromicroscopy: Biophysiological Analyses and Roles of Environmental Factors.

This study investigated the toxicity of triclosan to the green microalga Chlorococcum sp. under multiple environmental stressors. The interactions between triclosan and environmental stressors were explored through full two-way factorial, synchrotron-based Fourier transform infrared spectromicroscopy and principal component analyses. Phosphorus concentration, pH * phosphorus concentration, and temperature * pH * NaCl concentration were the most statistically significant factors under triclosan exposure. The variation of those factors would have a huge impact on biophysiological performances. It is interesting to find Chlorococcum sp. may become more resistant against triclosan in phosphorus-enriched environment. Besides, particular significant factors from multiple environmental stressors showed the impacts of triclosan on the corresponding response of Chlorococcum sp. owing to the specific structure and performance of biomolecular components. Moreover, two high-order interactions of temperature * pH * NaCl concentration and temperature * pH * NaCl concentration * phosphorus concentration had more contributions than others at the subcellular level, which could be attributed to the interactive complexity of biomolecular components. Due to cellular self-regulation mechanism and short exposure time, the biophysiological changes of Chlorococcum sp. were undramatic. These findings can help reveal the interactive complexity among triclosan and multiple environmental stressors. It is suggested that multiple environmental stressors should be considered during ecological risk assessment and management of emerging pollutants.

A framework designation for the assessment of urban ecological risks

ABSTRACTUrban ecological risks stemming from urbanization are increasing and limiting the capability of China to effectuate sustainable urban development. Therefore, addressing urban ecological risks is an urgent need. Numerous factors are involved in urban ecological risks, including air, water, and soil. Additionally, risk sources and risk receptors are complex and diverse. In this study, urban ecological risks are defined as adverse effects and possibility of impacts on urban ecosystem services resulting from urbanization. Urbanization is recognized as the risk source, and the urban ecosystem is considered the risk receptor. Based on this understanding, the components of urban ecological risks are defined, and the relationships between the components of urban ecological risks are illuminated by establishing an indicator system. Based on previous studies on urban ecological risks, an explicit framework for identification, assessment, and management of urban ecological risks is proposed. For purposes of identification, there are three types of risk sources: population growth, industrial development, and the expansion of built land. Stressors include the accumulation of contaminants, consumption of resources, and occupation of space. Assessment endpoints are divided into provisioning, regulating, cultural, and supporting services. In response to urban ecological risks having multiple stressors and multiple assessment endpoints, we assessed risks both with a single stressor/single endpoint and comprehensive ecological risks. In our framework, the physical or material assessment of ecosystem services is adopted as the core method for the analysis of urban ecological risk, because it is believed that the analysis of urban ecological risk should be based on the physical or material assessment of ecosystem services instead of the value assessment of ecosystem services. The results of the single value assessment of urban ecosystem services will cause the deviation from the purpose of urban ecosystem services assessment. The purpose of urban ecosystem services assessment is to maintain and/or improve the capability of urban ecosystems of providing physical or material services, and further to reduce or avoid the occurrence risks of unsustainable cities. Additionally, a multi-level characterization method was adopted for the results of urban ecological risk assessment. In this study, we established a platform to manage urban ecological risks based on landscape ecology and environmental internet of things technologies, and to effectuate online urban ecological risk identification, assessment, and management via this platform.

城市生态风险管理关键问题与研究进展

PDF HTML阅读 XML下载 导出引用 引用提醒 城市生态风险管理关键问题与研究进展 DOI: 10.5846/stxb201705140890 作者: 作者单位: 中国科学院生态环境研究中心 城市与区域生态国家重点实验室,中国科学院生态环境研究中心 城市与区域生态国家重点实验室,中国科学院生态环境研究中心 城市与区域生态国家重点实验室,中国科学院生态环境研究中心 城市与区域生态国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划（2017YFC0505702）；中国科学院前沿科学重点研究项目（QYZDB-SSW-DQC034）；国家自然科学基金项目（41601556） Review on urban ecological risk management Author: Affiliation: State Key laboratory for Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,State Key laboratory for Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,State Key laboratory for Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,State Key laboratory for Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:我国目前正处于社会经济转型和城市化进程加快时期，随着城市化发展和城市人居环境的变化，城市生态风险受到越来越多关注。在综述国内外城市生态风险管理研究进展，总结风险源与受体特点和风险评价方法的基础上，结合城市生态风险管理的需求，明确了城市生态风险的管理目标，将管理目标系统归纳划分为控制目标、调控目标和规划目标3个层次；在解析城市生态风险管理特点的基础上，结合风险管理目标从弹性力、动态管理性和空间异质性3个方面对生态风险管理措施与方案进行了总结分析，并进一步探讨了风险管理保障机制。从生态风险管理目标制定、构建城市生态系统特点的风险管理体系及其管理机制等方面提出了建议与展望，以期推动我国城市生态风险管理的发展。 Abstract:With rapid urbanization and social-economic transformation, the changes of ecological structure, processes, and functions in urban ecosystems have resulted in the broad decline of environmental quality and ecosystem services. Thus, urban ecological risk management is important to regulate and protect urban ecosystems, which have many vital issues regarding regional sustainable development. Based on the review of researches on ecological risk management, and risk sources, receptor characteristics as well as risk evaluation methods in urban ecosystems, we defined the objectives of urban ecological risk management according to the need for risk management, which can be interpreted as control objectives, regulation objectives, and planning objectives. Of these, the control objectives focus on the protected entities and relative attributes. The regulation objectives are defined as cost-benefit analyses of corresponding risk prevention. Finally, the planning objectives integrate risk management into the blueprint of urban planning. Being oriented toward characteristics of urban ecosystem risk management, the methods and models of ecological risk management were analyzed based on the aspects of resilience, dynamic management, and spatial heterogeneity. Considering the character of vulnerability and resilience in urban ecosystems, the restoration and regulation function of natural ecosystems should receive more attentions. Furthermore, building an ecological infrastructure is a key point to enhance response capacity, with integration and optimization of different adaptive capabilities. Ultimately, building a resilient community is the basic unit of risk management, and its construction norms and design features should be incorporated into urban planning and construction to promote the substantial progress of urban risk management. The effects of managing actions should be analyzed in accordance with scenario analysis, considering the dynamic character of urban ecosystems, changes in the landscape, and risk prevention. Management that optimizes the ecological pattern should be integrated into urban planning. The risk map could provide significant information for the management of specific ecological risks, whereas the best management plan could be formatted considering the demand, and require coordination and trade-offs among key regulating services. The mechanisms of urban ecological risk management are discussed at the end of the article and suggestions on urban ecological risk management are put forward including specifying risk management objectives, building a risk management framework with urban characteristics, and establishing a management mechanism. 参考文献 相似文献 引证文献

Post-release survival of two elasmobranchs, the eastern shovelnose ray (Aptychotrema rostrata) and the common stingaree (Trygonoptera testacea), discarded from a prawn trawl fishery in southern Queensland, Australia

Post-trawl survival (PTS) is an important metric used in determining the ecological risk posed by prawn (shrimp) trawling on discarded elasmobranchs. Despite this, PTS of elasmobranchs is poorly understood. The present study quantified the PTS of two small batoids caught incidentally by prawn trawlers in southern Queensland, Australia, namely the common stingaree (Trygonoptera testacea) and the eastern shovelnose ray (Aptychotrema rostrata). Field studies using on-board tanks revealed that A. rostrata were more resilient to trawl capture and release than T. testacea. For both species, survival was found to increase with size, whereas increasing time on deck resulted in lower survival. Female T. testacea were found to be more resilient than males, and increased tow duration resulted in lower survival for A. rostrata. The mean (±s.e.m.) PTS for female and male T. testacea was 33.5±6.0 and 17.3±5.5% respectively, compared with a mean PTS for A. rostrata of 86.8±3.2%. The survival estimates derived in the present study provide an insight into the effects of trawling on these species and will improve their ecological risk assessment and management.

Ecological risk assessment based on IHA-RVA in the lower Xiaolangdi reservoir under changed hydrological situation

Ecological risk assessment of river is an important content for protection and improvement of ecological environment. In this paper, taking Xiaolangdi reservoir for example, ecological risk assessments are studied based on the 1956-1997 and 2002-2008 dairy runoff data as the pre and post of construction of Xiaolangdi reservoir. Considering pre and post hydrological regime of construction of Xiaolangdi, ecological risk assessment index systems of downstream are established based on Index of Hydrologic Alteration-Range of Variability Approach method (IHA-RVA), which considering characters of flow, time, frequency, delay and change rate. Then ecological risk fuzzy comprehensive evaluation assessment model downstream is established based on risk index and RVA method. The results show that after the construction of Xiaolangdi reservoir, ecological risk occurred in the downstream of Yellow River for changed hydrological indexes, such as monthly average flow, frequency and duration of extreme annual flow and so on, which probably destroy the whole ecosystems of the river. For example, ecological risk downstream of Xiaolangdi reservoir upgrade to level two in 2008. Research results make reference values and scientific basis both in ecological risk assessment and management of reservoir after construction.

New approach to weight-of-evidence assessment of ecotoxicological effects in regulatory decision-making.

Ecological risk assessments and risk management decisions are only as sound as the underlying information and processes to integrate them. It is important to develop transparent and reproducible procedures a priori to integrate often-heterogeneous evidence. Current weight-of-evidence (WoE) approaches for effects or hazard assessment tend to conflate aspects of the assessment of the quality of the data with the strength of the body of evidence as a whole. We take forward recent developments in the critical appraisal of the reliability and relevance of individual ecotoxicological studies as part of the effect or hazard assessment of prospective risk assessments and propose a streamlined WoE approach. The aim is to avoid overlap and double accounting of criteria used in reliability and relevance with that used in current WoE methods. The protection goals, problem formulation, and evaluation process need to be clarified at the outset. The data are first integrated according to lines of evidence (LoEs), typically mechanistic insights (e.g., cellular, subcellular, genomic), in vivo experiments, and higher-tiered field or observational studies. Data are then plotted on the basis of both relevance and reliability scores or categories. This graphical approach provides a means to visually assess and communicate the credibility (reliability and relevance of available individual studies), quantity, diversity, and consistency of the evidence. In addition, the external coherence of the body of evidence needs to be considered. The final step in the process is to derive an expression of the confidence in the conclusions of integrating the information considering these 5 aspects in the context of remaining uncertainties. We suggest that this streamlined approach to WoE for the effects or hazard characterization should facilitate reproducible and transparent assessments of data across different regulatory requirements. Integr Environ Assess Manag 2017;13:573-579. © 2017 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

A novel label-free fluorescence assay for one-step sensitive detection of Hg2+ in environmental drinking water samples

A novel label-free fluorescence assay for detection of Hg2+ was developed based on the Hg2+-binding single-stranded DNA (ssDNA) and SYBR Green I (SG I). Differences from other assays, the designed rich-thymine (T) ssDNA probe without fluorescent labelling can be rapidly formed a T-Hg2+-T complex and folded into a stable hairpin structure in the presence of Hg2+ in environmental drinking water samples by facilitating fluorescence increase through intercalating with SG I in one-step. In the assay, the fluorescence signal can be directly obtained without additional incubation within 1 min. The dynamic quantitative working ranges was 5–1000 nM, the determination coefficients were satisfied by optimization of the reaction conditions. The lowest detection limit of Hg2+ was 3 nM which is well below the standard of U.S. Environmental Protection Agency. This method was highly specific for detecting of Hg2+ without being affected by other possible interfering ions from different background compositions of water samples. The recoveries of Hg2+ spiked in these samples were 95.05–103.51%. The proposed method is more viable, low-costing and simple for operation in field detection than the other methods with great potentials, such as emergency disposal, environmental monitoring, surveillance and supporting of ecological risk assessment and management.

Input-output model based ecological risk assessment for ecological risk management of watersheds: a case study in the Taihu Lake watershed, China

To achieve advanced watershed ecological management, policy-makers have struggled to predict ecological impacts for a long time. As a process of ecosystem analysis, ecological risk assessment (ERA) has been widely adopted to analyse the possibility of adverse ecological effects. ERA has developed from considering only a few indicators in an area to multiple sources and receptors in large-scope regions. However, the transfer of risk in large-scope regions caused by internal interaction has not been deeply analysed, especially in regions with complex internal interaction structures. This would lead to extensive management, where watershed-level policies may not be fit for some subregions, thus leading to limited management efficiency. In this study, we integrate an Input-Output (IO) model into the Relative Risk Model (RRM), and propose an IO model based ERA (IO-ERA) methodology, which would reveal the intensity of ecological risk caused by local sources, direct water flows and indirect transfers. An IO-ERA is conducted in Taihu Lake watershed as a case study, in which we could demonstrate that IO-ERA is capable of providing advanced insights of risk analysis in large-scope regions. The outcome of IO-ERA would support watershed administration to transfer from single standard regulation to diverse, dynamic and lean ecological risk management.

Distribution of antibiotic resistance in the effluents of ten municipal wastewater treatment plants in China and the effect of treatment processes

Municipal wastewater treatment plant (WWTP) effluents represent an important contamination source of antibiotic resistance, threatening the ecological safety of receiving environments. In this study, the release of antibiotic resistance to sulfonamides and tetracyclines in the effluents of ten WWTPs in China was investigated. Results indicate that the concentrations of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) ranged from 1.1 × 101 to 8.9 × 103 CFU mL−1 and 3.6 × 101 (tetW) to 5.4 × 106 (tetX) copies mL−1, respectively. There were insignificant correlations of the concentrations of ARB and ARGs with those of corresponding antibiotics. Strong correlations were observed between the total concentrations of tetracycline resistance genes and sulfonamide resistance genes, and both of which were significantly correlated with intI1 concentrations. Statistical analysis of the effluent ARG concentrations in different WWTPs revealed an important role of disinfection in eliminating antibiotic resistance. The release rates of ARB and ARGs through the effluents of ten WWTPs ranged from 5.9 × 1012 to 4.8 × 1015 CFU d−1 and 6.4 × 1012 (tetW) to 1.7 × 1018 (sul1) copies d−1, respectively. This study helps the effective assessment and scientific management of ecological risks induced by antibiotic resistance discharged from WWTPs.

Dissemination of antibiotic resistance genes and their potential removal by on-farm treatment processes in nine swine feedlots in Shandong Province, China

This work investigated the dissemination of antibiotic resistance genes (ARGs) encoding resistance to sulfonamide and tetracycline antibiotics in nine swine feedlots located in Shandong Province of China, and examined their potential removal by various on-farm treatment processes. Results indicate that the target ARGs were widely distributed in swine wastes, with mean relative abundances ranging from 3.3 × 10−5 (tetC) to 5.2 × 10−1 (tetO) in swine manure and from 7.3 × 10−3 (tetC) to 1.7 × 10−1 (tetO) in swine wastewater. The mean relative ARG abundances ranged from 9.9 × 10−5 (tetW) to 1.1 × 10−2 (tetO) in soils and from 3.1 × 10−4 (tetW) to 1.1 × 10−2 (sul2) in receiving river sediments, indicating that the farmland application of swine manure compost and the discharge of swine wastewater promoted the dissemination of ARGs into adjacent environments. Microbial fermentation bed (MFB) could reduce the relative ARG abundances by 0–1.18 logs. However, septic tank, biogas digester and natural drying methods were relatively ineffective for ARG removal, and the relative abundances of some ARGs (i.e., tetC, tetG, sul1, and sul2) even increased by 0.74–3.90 logs in treated wastes. Bacterial diversity analysis indicates that the evolution of bacterial communities in the MFB played a crucial role in eliminating the ARGs. This study helps the effective assessment and management of ecological risks arising from ARGs in swine feedlots.

Dynamic Ecological Risk Assessment and Management of Land Use in the Middle Reaches of the Heihe River Based on Landscape Patterns and Spatial Statistics

Land use profoundly changes the terrestrial ecosystem and landscape patterns, and these changes reveal the extent and scope of the ecological influence of land use on the terrestrial ecosystem. The study area selected for this research was the middle reaches of the Heihe River. Based on land use data (1986, 2000, and 2014), we proposed an ecological risk index of land use by combining a landscape disturbance index with a landscape fragility index. An exponential model was selected to perform kriging interpolation, as well as spatial autocorrelations and semivariance analyses which could reveal the spatial aggregation patterns. The results indicated that the ecological risk of the middle reaches of the Heihe River was generally high, and higher in the northwest. The high values of the ecological risk index (ERI) tended to decrease, and the low ERI values tended to increase. Positive spatial autocorrelations and a prominent scale-dependence were observed among the ERI values. The main hot areas with High-High local autocorrelations were located in the north, and the cold areas with low-low local autocorrelations were primarily located in the middle corridor plain and Qilian Mountains. From 1986 to 2014, low and relatively low ecological risk areas decreased while relatively high risk areas expanded. A middle level of ecological risk was observed in Ganzhou and Minle counties. Shandan County presented a serious polarization, with high ecological risk areas observed in the north and low ecological risk areas observed in the southern Shandan horse farm. In order to lower the eco-risk and achieve the sustainability of land use, these results suggest policies to strictly control the oasis expansion and the occupation of farmland for urbanization. Some inefficient farmland should transform into grassland in appropriate cases.