Ecological risk assessment of heavy metal-contaminated soil using the triad approach

Journal of Soils and Sediments - Heavy metal soil-pollution is of concern due to its adverse effects on the ecosystem and human health. However, conventional ecological risk assessments considering...     

基于物质流分析的高集约化农区环境风险评价

该文将经济-环境系统研究领域的物质流分析方法运用在高集约化农区的环境风险评价中,构建了高集约化农区环境风险指数模型,并以湖南省桃江县为案例区,分析测算了2001-2012年的物质输入-输出变化,对高集约化农区环境风险进行了初步评价。结果显示:1)以人口压力、农业产值、耕地面积和农业技术水平为主要驱动力,农产品的生产增加,但物质投入和物质输出指标在12 a间波动上升,物质投入的增加导致了污染排放的同步增长;2)人均物质投入、人均物质产出持续提高,资源生产率和环境效率降低,创造单位农业经济产值的资源消耗和污染排放量有所下降;3)总体环境风险在2004年之后增加,但以2010为转折点开始得到有效控制;4)基于物质流分析的环境风险评价方法可较全面的反映高集约化农区环境风险的演变规律及结构特点,较好的揭示环境风险的发展程度及变化特征。     

复杂地形地貌背景区干旱风险评价

为解决当前复杂地形地貌背景区干旱风险评价研究普遍缺乏足够针对性的问题,以四川省为例,基于自然灾害风险理论,综合气象、水文、地形地貌、实际灾害和人口与社会经济等各方面信息构建评价指标体系,并从复杂地形地貌背景区的角度进行指标因子的计算。通过构建复杂地形地貌背景区的评价指标体系,并利用熵权赋权法,实现了基于格网的四川省干旱风险评价,得到了能够实际反映研究区干旱风险的、较为可靠的结果。结果显示,四川盆地大部和川西南攀枝花、凉山州部分地区干旱灾害风险等级高;广元、巴中、达州北部地区,凉山州和攀枝花市大部分地区以及宜宾市和泸州市南部地区,川西高原的部分河谷地带分布有一般等级的干旱风险;川西高原大部分地区风险较低。本研究,尤其在因子指标体系构建方面的研究,对类似复杂地形地貌背景区干旱风险评价工作的开展具有一定的借鉴意义。     

农田磷的环境风险及评价研究进展

本文综述了农田磷环境风险及其评价研究进展。着重阐述了农田磷的迁移途径、农田土壤磷水平、土壤磷的吸附和解吸特性以及磷肥和有机肥用量等对农田磷地表径流流失和渗漏的影响;农田土壤磷环境风险评价方法及P-index评价方法的建立和应用等。提出了今后该领域的研究方向。     

典型地区多介质环境中多氯联苯、镉致癌风险评估

对典型地区多种环境介质土壤(n=151)、地下水(n=9)、大气(可吸入颗粒物(PM10)和气态污染物,n=4)及农作物(蔬菜(n=38)和大米(n=95))进行采样,分析其中多氯联苯(PCBs)和镉(Cd)含量,利用美国EPA致癌风险评估模型评估研究区居民经多种途径接触多种介质引起的PCBs和Cd的致癌暴露剂量和致癌风险.进行致癌风险贡献率分析,筛选出主要的致癌污染物、暴露途径及对致癌风险贡献最大的环境介质.研究结果表明,所调查的环境介质中均存在严重的PCBs、Cd污染,蔬菜和大米中Cd的平均含量分别为我国食品中污染物限量标准的130倍和17倍,地下水中PCBs和Cd超标率均很高,大气中气态PCBs及PM10颗粒态PCBs、Cd含量均高于国内外其他地区的调查结果.致癌暴露剂量评估结果表明PCBs、Cd的总致癌暴露剂量分别为允许摄入量的6.8倍和6.1倍,总致癌风险为1.1×10-3,远高于国内外所规定的可接受致癌风险水平;致癌贡献率分析结果表明经口摄入是研究区居民致癌风险的最主要暴露途径,蔬菜、大米和地下水是该地区最主要的PCBs、Cd致癌风险来源.     

大同市区主要蔬菜生产基地环境质量评价分级

对山西省大同市区主要蔬菜生产基地进行环境质量评价及其分级结果表明,该区主要蔬菜生产基地环境质量总体优良,完全满足目前国家所规定的无公害蔬菜或绿色食品产地环境质量的要求。     

Survival of trees in a metal-contaminated environment

This study investigates the survival of sycamore (Acer pseudoplatanus) trees at a metal contaminated site where populations of herbaceous flora are known to have evolved metal tolerance. The incidence of pollution at the site relates to a copper refinery, the existence of which is pre-dated by many trees in the area. High soil levels of Cu, Cd, Zn and Ph were recorded to depths of 40 to 90 cm. Tolerance tests on tree seedlings carried out in soils showed no evidence that the trees produce tolerant offspring. Cell culture growth experiments on explant material from shoot meristems of mature trees did show increased tolerance to Cu, compared with material originating from unpolluted sites. The significance of these findings is discussed in relation to facultative adaptations providing trees with the resilience to withstand pollution impact.

     

生鲜乳中兽药残留的快速筛查与风险预警体系构建

该研究探索并构建一种基于历史数据分析的安全预警方法,对生鲜乳中兽药残留情况进行识别、控制与评价,以便在风险发生之前做出准确判断。首先利用高效液相色谱-高分辨飞行时间串联质谱(High Performance Liquid Chromatography-high Resolution Time-of-flight Tandem Mass Spectrometry,HPLC-TOF-MS/MS)方法对上海市各牧场的生鲜乳进行兽药残留筛查,然后以生鲜乳中泼尼松(Prednisone,Pre)残留检出数为例,利用休哈特控制图(Shewhart control charts)构建风险预警体系。结果表明:在300个生鲜乳样品中共筛查出42种兽药残留,涉及类固醇类(12种)、糖皮质类(6种)和镇静剂(5种)等12大类;在筛查的6个星期中,泼尼松检出数(Number of Prednisone Detected,Pn)控制图呈现稳定的状态;当假设第7周泼尼松检出数为6时,Pn控制图呈现稳态,未触发预警;当假设第7周泼尼松检出数为10时,Pn控制图出现异常,稳态遭到破坏,此时该批样品触发风险预警。综上,利用HPLC-TOF-MS/MS能对生鲜乳样品进行高通量的兽药残留筛查,再利用休哈特控制图结合历史数据可以对生鲜乳样品的兽药残留进行有效的风险监测和预警。     

Combining landslide and contaminant risk: a preliminary assessment

Background, aim, and scope

The aim of this paper is to highlight a not yet recognized hazard for mass failure (landslides) of contaminated soils into rivers and to provide an understanding of important interactions of such events. A first effort to investigate the problem is made focusing on the south eastern part of the Göta Älv river valley, in Sweden, by combining geographical information on potentially contaminated sites with slope stability levels on maps. The objectives of this study were to: (1) Review current Swedish risk assessment methodologies for contaminated areas and landslides, and analyze their capability to quantify the risk of contaminated areas being subject to landslides. (2) Investigate the presence of contaminated areas at landslide risk along the Göta Älv river valley. (3) Provide an overview of the national methods for landslide risk analysis and for environmental risk classification, followed by a comparison between the methods and the results from the superposition of the two methods for the study site. (4) Make a first attempt to conceptualize the release and transport mechanisms.

Materials and methods

Environmental risk assessment data of the study site was combined with data on slope stability levels. Conceptual issues of the release and transport scenario were identified and a first conceptual model was created.

Results

Of 31 potentially contaminated sites, eight had moderate to high probability for landslide, and of these eight sites, five were classified as having a high or very high environmental risk. These findings had not been revealed when the data had only been considered separately. The ‘actual’ risk could hence be even higher than the highest environmental risk class actually suggests. By visualizing results from the landslide risk analysis with the results from the environmental risk classification of contaminated sites, a better understanding of the potential hazard involved is obtained.

Discussion

The release mechanisms as a result of a landslide into surface water were conceptualized using two time scales: the instantaneous and the long-term release. It is clear that the Swedish method for landslide risk assessment and for environmental risk assessment of contaminated soil considers hazard events that are characterized by different time scales. The method for landslide risk assessment addresses events that are rapid (occurring over minutes) with instantaneous impact and consequences. Measurements are made within a short time after the event (days to months). The environmental risk assessment is done with respect to events that are slowly evolving (over years or decades) and any possible consequence materializes after a long period of time.

Conclusions

The combined data provided a more solid basis for decisions; however, inherent difficulties when combining data based on different methods were revealed. Separate assessment methodologies executed by different authorities may lead to incorrect assessments and inappropriate protective measures.

Recommendations and perspectives

The effects and the consequences of landslides in areas with contaminated soil need to be further investigated. The climate change expected to occur over the next hundred years will increase the probability of slope failures, such as landslides, in many parts of the world where the precipitation is predicted to increase (e.g., in Scandinavia). This will accentuate the need for methods and models to assess the impact of such events. In order to achieve established environmental quality objectives there is an urgent need for models and assessment principles (criteria) for contaminated areas that are at risk of experiencing slope failure. Knowledge of the governing processes that control the release and transport of substances under a variety of conditions, taking into account characteristic spatial and temporal scales, is required.     

Erosion risk assessment: A contribution for conservation priority area identification in the sub-basin of Lake Tana,north-western Ethiopia

Soil erosion is a serious environmental problem arising from agricultural intensification and landscape changes. Improper land management coupled with intense rainfall has intricated the problem in most parts of the Ethiopian highlands. Soil loss costs a profound amount of the national GDP. Thus, quantifying soil loss and prioritizing areas for conservation is imperative for proper planning and resource conservation. Therefore, this study has modeled the mean soil loss and annual sediment yield of the Gumara watershed. Landsat 5 TM, Landsat 7ETM+, and Landsat 8 OLI were used for land use land cover (LULC) change analysis. Besides these, other datasets related to rainfall, digital soil map, Digital Elevation Model, reference land use, and cover (LULC) ground truth points were used to generate parameters for modeling soil loss. The watershed was classified into five major land-use classes (water body, cultivated land, grazing land, built-up and forest and plantation) using a maximum likelihood algorithm covering a period of the last 30 years (1988–2019). The mean annual soil loss and sediment yield were quantified using RUSLE, Sediment delivery ratio (SDR), and Sediment Yields models (SY). The analysis result unveils that within the past 30 years, the watershed has undergone significant LULC changes from forest & plantation (46.33%) and grazing land to cultivated land (31.59%) with the rate of ?1.42km²yr^-1 and -2.80km²yr^-1 respectively. In the same vein, the built-up area has expanded to cultivated and grazing land. Subsequently, nearly 15% (207 km²) of the watershed suffered from moderate to very severe soil loss. On average, the watershed losses 24.2 t ha?¹ yr?¹ of soil and yields 2807.02 t ha?¹ yr?¹ sediment. Annually, the watershed losses 385,157 t ha?¹ yr?¹ soil from the whole study area. Among the admirative districts, Farta (Askuma, Giribi, Mahidere Mariam and Arigo kebeles), Fogera (Gazen Aridafofota and Gura Amba kebeles), East Este (Witimera kebele), and Dera (Gedame Eyesus and Deriana Wechit kebeles) districts which cover 50% of the watershed were found severely affected by soil erosion. Thus, to curve back this scenario, soil and water conservation practices should prioritize in the aforementioned districts of the watersheds.     

近电器拆解区土壤-蔬菜多氯联苯污染及其健康风险

选择浙江省某典型电器拆解区,研究了该区域附近农田土壤和蔬菜中多氯联苯的污染水平,并进行健康风险评价。结果表明,该区农田土壤中PCBs含量为6.78～15.48μgkg^-1,蔬菜样品中PCBs平均含量为5.98～130.70μg kg^-1,与西藏土壤的背景值和浙江省农村土壤的PCBs污染水平比较,电器拆解区附近农田存在PCBs累积污染。以食物链为主要暴露途径的健康风险评价结果表明,生命期致癌风险水平为6.50×10^-6～1.24×10^-4,超过PCBs致癌基准浓度对应的生命期致癌风险水平1～3个数量级;生命期非致癌风险水平在部分农田大于可接受风险水平（HQ=1）。该区域农田生态系统中土壤和部分常见蔬菜存在多氯联苯污染,已构成较大的人体健康风险。     

基于磷指数模型的海河流域农田磷流失环境风险评价

农田面源磷流失是导致水体富营养化的主要原因,识别农田磷流失的关键源区、影响因子是农田面源污染防治的重要环节。该研究以海河流域为研究区,采用磷指数模型,选取土壤有效磷含量、磷肥施用量作为源因子,以土壤侵蚀模数、年径流深、农田和水体间归一化距离指数作为迁移因子,结合GIS技术评估海河流域农田磷流失风险,并利用结构方程模型研究农田磷流失风险指数与各影响因子间关系。结果表明:1)海河流域农田土壤有效磷、磷肥施用量、土壤侵蚀模数、年径流深及归一化距离指数处于中-低、中-高、极低、中-高和高级别风险等级的区域面积占比最高,分别占农田总面积的66.5%、61.1%、99.0%、54.2%和64.8%;2)影响农田磷流失的关键因子为迁移因子,其中关键的迁移因子为年径流深及归一化距离指数;3)源因子与迁移因子间呈极显著负相关(P0.01),土壤性质(包括土壤质地及有机碳含量等)与源因子呈极显著负相关(P0.01),与迁移因子呈极显著正相关(P0.01);4)海河流域农田磷流失关键源区位于黄河北岸的山东省和河北省东南部的平原农耕区、海河流域西北部的山区地带。该研究结果对流域尺度上农田磷流失研究的方法创新有所裨益,可为海河流域农田面源污染防治提供科学参考。     

Selecting for nutrient use efficiency within forage grass species: I. Development of a screening system

One means of achieving increased forage grass production on infertile soils is to select plant genotypes which grow efficiently at low levels of available nutrients. This requires methods to identify variability in individual plant nutrient response from among large populations of plants grown under controlled environmental conditions.

A compact, containerized system, partially developed for growing large numbers of forage grass seedlings for use in automatic machine transplanter research, was adapted as the basis for such a screening technique. Three trials were made with 100‐plant samples of a kleingrass‐75 (Panicum coloratum L.) population to test the utility of the system. Results of these trials showed that differences in nutrient use efficiency (= reciprocal of nutrient concentration in the plant tissue, or milligrams dry matter produced per milligram nutrient absorbed) among the grass plants could be effectively identified by using the system in conjunction with laboratory analysis of the material grown. Plants could be maintained in vigorous condition during several harvest periods, and those selections that were retained could be easily transplanted for further propagation and evaluation.     

Small area estimation in a Watershed erosion assessment survey

This article describes an application of small area estimation in a survey conducted in the Rathbun Lake Watershed in Iowa (USA). From a sample of 183 plots in the watershed, erosion from four sources as well as total erosion are estimated for 61 small areas within the study region. Information on land cover and topography from GIS coverages are used to create plot-level covariates for the regression model. Two estimators are discussed in the article: an empirical best linear unbiased predictor and a composite estimator. The latter estimator is potentially less efficient than the former, but preserves the additivity between the estimates for the four erosion sources and the total erosion. For this survey, the estimated efficiency loss is shown to be very small.     

河南省大气重金属沉降高风险区蔬菜重金属含量及健康风险评估

  【目的】  我们研究了大气重金属沉降高风险区菜地重金属的污染状况及污染来源,评价了研究区种植的蔬菜对不同人群(男性、女性、成人和青少年)产生的健康风险,并筛选了低累积重金属的蔬菜类型。  【方法】  在河南省大气重金属沉降风险高的蔬菜产区进行调查。分别采集设施栽培和露地条件下种植的叶类(青油菜、青菜、香菜)、葱蒜类(大蒜)、茄科类(茄子、辣椒、番茄)、瓜果类(苦瓜、黄瓜)、豆类(长角豆、四季豆)和块根类(萝卜)蔬菜样品,分析了蔬菜可食用部位Cd、Pb含量及富集能力,讨论了其主要的污染来源,并利用Monte Carlo模拟,对不同种类蔬菜可食用部位进行概率非致癌健康风险评价。  【结果】  设施栽培和露地条件下,蔬菜可食用部位Cd的富集系数均高于Pb。不同类别的蔬菜对重金属的吸收能力存在明显差异,瓜果类蔬菜为Cd、Pb低累积蔬菜,设施栽培条件下瓜果类蔬菜可食用部位积累的Cd、Pb含量最低,Cd、Pb含量分别为0.020、0.036 (黄瓜)和0.008、0.055 (苦瓜) mg/kg,低于食品重金属污染限值。对比设施栽培和露地条件下种植的蔬菜可食用部位的污染程度发现,露地条件下蔬菜Cd、Pb的污染程度更高,大部分叶类蔬菜和葱蒜类蔬菜为重度污染,其中青油菜Cd内梅罗综合污染指数(P_N)达到10.26,P_N (Pb)达到了10.00。概率风险评价结果表明,不同人群摄入Cd、Pb污染蔬菜产生的复合非致癌健康风险差别不大,其中摄入瓜果类和块根类蔬菜对人体没有明显的负面影响,尤其是瓜果类蔬菜,设施栽培下,成年男性摄入苦瓜产生的总目标危险系数的P₇₅ (第75百分位点)仅为0.120。  【结论】  不同类型蔬菜的Cd、Pb富集能力差异显著,叶类蔬菜对Cd、Pb富集能力最强,瓜果类较弱,尤其是苦瓜。污染区设施栽培的瓜果和豆类蔬菜可安全食用。大气沉降是蔬菜Pb污染的重要来源之一,建议在大气重金属沉降高风险区进行设施栽培,选择低积累Cd、Pb的瓜果类蔬菜,降低重金属对人体健康产生的风险。     

滇池流域不同利用方式下红壤磷素渗漏环境风险评价

为对滇池流域不同利用方式下红壤磷素渗漏环境风险进行评价,采用土柱模拟试验并进行相关性分析及聚类分析。结果表明:(1)不同利用方式下红壤中的藻类可利用总磷(NaOH-P)、溶解态活性磷(CaCl2-P)的含量与有效磷(Olsen-P)含量一致,呈现大棚露地草地的趋势,磷吸持指数(PSI)呈现草地大棚露地的趋势;(2)在同种土地利用方式下渗滤液中存在全磷(TP)颗粒态磷(PP)可溶性全磷(TDP)可溶性有机磷(DOP)钼酸盐反应磷(MRP)的趋势,渗漏液中TP含量呈现大棚露地草地的趋势;不同利用方式下DOP、TDP、PP和MRP含量差异不显著,且与TP含量趋势相同;(3)Olsen-P与渗漏液的TP、TDP、PP和DOP具有显著相关性;(4)当Olsen-P40 mg/kg、PSI50时对流域水体富营养化无显著影响;当Olsen-P为40～71mg/kg,PSI40时对流域水体富营养化有一定影响;当Olsen-P71 mg/kg,PSI30时对流域水体环境富营养化具有显著影响。     

Invertebrates in risk assessment development of a test battery and of short term biotests for ecological risk assessment of soil

4 Conclusion  In general, all biotests used in the ring test are applicable for risk assessment of field soil and contaminated or remediated soil material. Of these, the most sensitive tests were selected as a integral part of the test battery [4]. This selection did not consider either the duration of the tests, which is crucial for the acceptance of tests by the remediation industry, and the effects of pollutants on biomarkers, which indicate the departure of an organism from its normal biochemical or physiological status. Therefore, the proposed test battery has to be supplemented with biotests of short duration. The best choice for a short test using the endpoint reproduction is the biotest withCaenorhabditis elegans which characterises the habitat function of soil. The appropriate screening test for the retention function is the ETr (electron transfer) inhibition test with submitochondrial particles, which provides reliable results in less than 15 min. For screening the habitat function, avoidance tests with soil invertebrates like annelids or enchytraeids are optimal, as both annelids are exposed to the bioavailable pollutants in the soil pore water. The effect of environmental chemicals at the individual level and below can be analysed with the Celegans ToxChip, which gives information of the status of biomarkers on the molecular and biochemical level. Preliminary SOPs for these biotests are formulated. They have still to be evaluated by international ring tests.     

The assessment of sediment screening risk in Venice Lagoon and other coastal areas using international sediment quality guidelines

Background, Aims and Scope  A number of studies carried out in recent years have shown the presence of a wide range of contaminants in the Venice Lagoon. It is important to have a good understanding of the ecological quality of Venice Lagoon sediments, in order to: i) define and locate areas where a threat to the environment is present and therefore an intervention is needed (i.e. in situ assessment and management); and ii) define sustainable and environmentally correct ways of managing sediments which are to be dredged for navigational purposes or in relation to other interventions (i.e., ex situ management). Methods  To examine how various regional and international SQGs ‘classed’ screening risk in Venice Lagoon sediments, data on median contaminant levels in surface sediments in Venice Lagoon resulting from a literature review were compared to a range of local and international sediment quality guidelines (SQGs). Then data on sediment contaminant levels in various areas and sub-basins of Venice Lagoon (main Lagoon, Porto Marghera and Venice City Canals) and in other regional and international transitional and coastal ecosystems with various levels of human impact (urbanization and industrialization) were evaluated based upon a selected consensus-based SQG. Finally, screening sediment quality for all of Venice Lagoon was mapped and contoured, relative to this consensus-based SQG and briefly compared with direct toxicity measurement through a battery of bioassays. Results  SQGs allow the sediment areas to be put in terms of potential, or screening, risk. Although there were some differences depending upon which specific SQGs were applied, the Venice SQGs and other international SQGs provided the same general picture of screening risk in Venice Lagoon despite geographic differences. Venice Lagoon South has the lowest screening risk levels, Venice Lagoon Central/North has the highest (and is nearest to the Porto Marghera and Venice City Canals sites). Discussion  The Venice Lagoon sediments have hazard quotients on the low end of the range of moderately urbanized and industrialized sites and higher than background case studies reviewed. Hg levels in the Venice Lagoon were generally higher than equivalent sites, while other contaminants were either equivalent or lower. In Porto Marghera (PM) and Venice City Canals (VC), for many contaminants of interest, PM, and for some, VC sediments have the highest levels of any case study reviewed. Ranges are high, so in all cases, remedial or disposal decisions should be based upon site-specific (and preferably tiered) data. Conclusions  The use of hazard quotients makes it possible to compare screening risks due to different mixes of contaminants within and between sites, but results should be interpreted with caution. How these sites rank when compared to some of the other highly industrialized sites depends upon how data are synthesized and communicated. Actual risk must be evaluated using a weight of evidence (WOE) approach, as site-specific bioavailability and background levels will differ both regionally and internationally. Recommendations and Perspectives  Whilst there are subtle differences, the current Venice sediment classifications (A, B and C) ‘performed’ in a similar manner to SQGs in similar classes, suggesting that regions of Venice Lagoon would not be classified much differently if other SQGs such as TEL, ERL, PEL, ERM or AET were adopted. The Italian sediment quality objectives, on the other hand, are significantly more conservative than any other SQGs examined, with the exception of the Flemish Reference values. A number of European nations are considering criteria based upon contaminant levels in relatively pristine modern sites, or based upon derivations of historical (pre-anthropogenic) contaminant levels. When used as a standard, such an approach lacks discriminating power, designating almost all sediments within an urbanized or industrialized region as of concern, or even, in many cases, mandating action or prohibiting various management approaches in a large percentage of sediments. While generally based upon the laudable desire to return sites to unimpacted levels, there is a risk that overprotective criteria have the opposite effect: by designating too large a percentage of sediments as requiring management or control, limited resources may be improperly allocated. Which set of SQGs is most ‘appropriate’ for the Venice Lagoon sediments depends upon the questions being asked. However, the Venice classifications are currently being used as pass-fail criteria, without consideration of site-specific conditions. The fact that they performed similarly to SQGs in similar classes suggests that any work to develop more site-specific SQGs (with the same general decision classes) would probably not make much difference in how sediments were ultimately classified and managed unless the fundamental approach was changed from a pass-fail to a tiered and WOE approach integrated in a comprehensive decision framework. For Venice Lagoon, and for other regions, although SQGs should be developed with care, in a scientifically defensible and risk-based manner, an equally or more important issue to be addressed is their role in overall decision frameworks. ESS-Submission Editor: Dr. Marc Babut (marc.babut@cemagref.fr)     

四川省化肥面源污染环境风险评估及趋势模拟

系统评估农业化肥过量施用对生态环境的潜在风险危害,可为制定下一阶段农业面源污染防治工作提供决策参考。本文基于2000—2015年化肥施用量和耕地面积等数据,采用化肥施用环境风险评价模型,探讨了四川省化肥施用及环境风险的时空变化特征;通过设置延续现状和政策干预两种情景,模拟了四川省2016—2018年执行化肥施用零增长行动期间的化肥施用环境风险变化趋势。结果表明:四川省化肥施用总量在2000—2015年间整体呈增加态势,2015年四川省化肥施用强度为376.63 kg?hm~(-2),超过了中国生态市建设的化肥施用强度250 kg?hm~(-2)的生态标准。四川省2015年化肥施用的环境总风险指数为0.69,处于中等风险程度;氮、磷、钾肥施用的环境风险指数分别为0.69、0.72和0.46。钾肥施用的环境风险处于安全状态;氮肥和磷肥的环境风险区域集中在成都平原经济区、川南经济区和川东北经济区,呈现中等风险程度并有成片聚集特征。延续现状情景下,四川各地区化肥施用环境总风险指数处于0.48~0.69,存在不同程度增加。与延续现状情景相比,四川在完成化肥施用零增长行动的任务规划前提下,2016—2018年政策干预情景的化肥施用环境总风险呈现下降趋势。以关键时间点2018年来看,川东北经济区化肥施用环境总风险下降最明显,较2015年执行化肥零增长时下降4.24%。但四川省多数地区仍存在不同程度的化肥施用环境污染风险,当地生态环境具有明显压力。建议省级部门加强对成都平原经济区和川东北经济区的化肥面源污染监测,根据各地区差异特征制定不同施肥方案,协调粮食增产和生态保护间的关系。