Approaches to Ecological Risk Characterization and Management: Selecting the Right Tools for the Job

Chemical-specific hazard quotient (HQ) risk characterization in ecological risk assessment (ERA) can be a value-added tool for risk management decision-making at chemical release sites, when applied appropriately. However, there is little consensus regarding how HQ results can be used for risk management decision-making at the population, community, and ecosystem levels. Furthermore, stakeholders are reluctant to consider alternatives to HQ results for risk management decisions. Chemical-specific HQs risk characterization should be viewed as only one of several approaches (i.e., tools) for addressing ecological issues; and in many situations, other quantitative and qualitative approaches will likely result in superior risk management decisions. The purpose of this paper is to address fundamental issues and limitations associated with chemical-specific HQ risk characterization in ERA, to identify when it may be appropriate, to explore alternatives that are currently available, and to identify areas that could be developed for the future. Several alternatives (i.e., compensatory restoration, performance-based ecological monitoring, ecological significance criteria, net environmental benefit analysis), including their limitations, that can supplement, augment, or substitute for HQs in ERA are presented. In addition, areas of research (i.e., wildlife habitat assessment/landscape ecology/population biology, and field validated risk-based screening levels) that could yield new tools are discussed.     

Toxicological evaluation of multi-class pesticide residues in vegetables and associated human health risk study for adults and children

This article describes, for the first time in 10 years, the toxicological evaluation of pesticide residues in highly consumed vegetables (35 commodities) and health risk studies. Among 1075 vegetable samples consisting mainly of tuber, root, fruiting, and Brassica, 20% of samples contained 38 pesticides in the range of 0.005–18.7 mg/kg and 1% > maximum residue limits (MRLs). Organophosphates and chloronitrile were most frequently found (20%) in the pesticide class. The highest concentration of 18.7 mg/kg was noted for dichlofluanid. Fruiting vegetables (8%), especially tomatoes (5%), were the most contaminated, while multi-residues were determined in 5% of the samples. Risk assessment was performed by analytical results and consumption on the 97.5 percentile expressed as hazard index (HI) and hazard quotient (HQ). The highest chronic HI was calculated for diazinon in lettuce (32% Acceptable Daily Intake (ADI) adults and 36% children) and for forbidden dieldrin in carrots (26%, 62% ADI). The highest acute HI was estimated for dichlofluanid in lettuce (69% Acute Reference Dose (ARfD)) for adults, whereas for children it was above the acceptance values of ARfD (168%). Organophosphate insecticides with common mode of action showed the greatest HQ (108% ADI). Vegetables may not be a serious problem for consumers, but investigations on pesticide residues are necessary to ensure food safety and the protection of human health, especially toward children who are more highly exposed to pesticides than adults.     

Human health risk assessment of arsenic in groundwater aquifers of Lahore,Pakistan

The present study was conducted to estimate As concentration in groundwater and resulting human health risk in terms of chronic daily intake, hazard quotient (HQ), hazard index (HI), and carcinogenic risk (CR) both for oral and dermal exposure to As. Groundwater samples (n = 100) were collected from ten different towns of Lahore District (Pakistan). Arsenic concentration ranged from 2 to 111 µg L^?1 in groundwater samples of the study area, which was significantly greater than the safe limit of As (10 µg L^?1) in drinking water set by the World Health Organization. Health risk assessment of As showed that HQ (0.1–11) for oral exposure and HI (0.1–11) values also exceeded the typical toxic risk index value of 1. 9.75 × E-05–4.59 × E-03 and 5.89 × E-07–2.77 × E-05 for oral and dermal As exposure, respectively. Both CR and cancer index (CIs) values were higher than United States Environmental Protection Agency limit (10^?6), suggesting that people are at high risk of As-induced carcinogenicity from oral and dermal exposure to As in drinking water. It was concluded that As contamination of groundwater causes carcinogenic and noncarcinogenic health effects to the people; therefore, urgent management and remedial actions are required to protect people from As poisoning.     

Can Ecological Receptors Really Be At Risk?

Birds and mammals at hazardous waste sites are routinely modeled for their potential to display harmful toxicological effects as a result of their exposures to contaminants. Although standard desktop measures of the potential for toxicological endpoints to be reached commonly suggest that these receptors should be at ill health (e.g., experiencing reproductive impairment), evidence is lacking from the field that such effects are occurring. Plausibly, the excessive time lapse (frequently several decades) from contaminant release event to site ecological risk assessment, can explain the disconnect. Aided by their relatively brief life spans, these modeled ecological receptors have produced multiple generations to date and may have outbred the chemical stress. In light of the absence of observed health impacts in birds and mammals since the creation of the U.S. Environmental Protection Agency's Superfund program, there may be no need to continue assessing the health of these species. Additionally, given the very few reported instances of observed health effects at terrestrial sites, it may be prudent to replace risk assessment with impact assessment as the essence of a revamped ecological assessment process.     

Evaluation of metal contamination and risk assessment to human health in a coal mine region of India: A case study of the North Karanpura coalfield

The present study aimed to evaluate metal contamination level in coal mine water of the North Karanpura coalfields and assess the possible health risk due to the intake of untreated mine water. Fourteen coal mine water samples were collected from the study area and analyzed for Al, As, Ba, Cr, Cu, Fe, Mn, Ni, Se, and Zn using inductively coupled plasma-mass spectroscopy (ICP-MS). The heavy metal pollution index (HPI) was used to calculate metal pollution level in the coal mine water. The hazard quotient (HQ) and hazard index (HI) were estimated for health risk to child and adult by using the United States Environmental Protection Agency (USEPA) methods. The concentrations of Al, Fe, Mn, and Ni in coal mine water were exceeding the acceptable as well as the maximum permissible limits specified for drinking and domestic uses. The HPI values were below the critical pollution index level of 100 except at one location. The estimated HQ and HI values for adult and children were greater than the standard limits in nearly half of the water samples. High HQ and HI values suggest that suitable treatment of coal mine water will require before its utilization in domestic and drinking purposes.     

区域生态风险评价的关键问题与展望

区域生态风险评价具有多风险因子、多风险受体、多评价终点、强调不确定性因素以及空间异质性的特点,它与传统的生态风险评价在风险源、胁迫因子和评价尺度上具有明显区别。尝试建立了一个基于陆地生态系统的区域生态风险评价框架,同时针对目前区域生态风险评价的研究现状,指出不确定性分析、尺度外推难、评价指标不统一、评价标准不统一、风险因子筛选及优先排序、区域内污染物复合、水生过渡到陆生生态系统风险评价、特殊的人为因素等是目前区域生态风险评价存在的关键问题及难点所在,并提出解决这些问题可能所需的工具、手段和理论方法突破。最后指出区域生态风险观测与数据采集加工、区域生态风险指标体系的统一与整合、区域生态风险评价方法论、区域生态风险的空间分布特征与表达以及区域生态风险评价反馈与管理机制5个方面是区域生态风险评价未来的研究重点。     

Bioaccumulation of Key Metals and Other Contaminants by Seaweeds from the Egyptian Mediterranean Sea Coast in Relation to Human Health Risk

This study examined the bioaccumulation of key metals and other contaminants (SO₄, F, Na, K, Ca, Mg, P, Si, Fe, Mn, Zn, Ni, Co, Cu, and Cd) by seaweeds from the Egyptian Mediterranean Sea coast and their risk to human health. Bioaccumulation factor calculations indicated that S, F, Na, K, Zn, Cu, and Cd had high seaweed uptake and this referred to the potential pollution of the coastal area. Multivariate analysis of the studied contaminants confirmed the bioaccumulation factor results as well as the physiological processes in seaweeds. Human health risk assessment of F, Mn, Zn, Ni, Cu, and Cd was conducted using hazard quotient (HQ) and incremental lifetime cancer risk (ILCR) analyses. The carcinogenic assessment of sediments and ingestion of seaweeds using ILCR calculations revealed that Mn, Ni, and Cd in sediments and F and Zn in seaweeds require remedial action in order to reduce their human health risks. Additionally, HQ calculations for the contaminants in seaweeds and reference to toxicological references values from different agencies revealed that F and Co present high human health risk effects. Consequently, the potential public health risks from dietary exposure to hazardous contaminants in seaweeds must be continually subjected to research, regulation, and debate.     

Health risk assessment due to exposure of arsenic contamination in drinking water of district Shiekhupura,Punjab, Pakistan

Abstract

The present study was conducted to assess the magnitude and health impacts of As in drinking water. Drinking water samples (n?=?60) were collected from twenty different sites of Shiekhupura District (Pakistan). Health risk assessment through average daily dose (ADD), hazard indices (HI), hazard quotient (HQ), carcinogenic risk (CR), and cancer indices (CI) for dermal and oral exposure were determined. Results revealed that As concentration ranged from 2 to 900?µg?L^?1 in water samples, which was significantly greater than the safe limit of As (10?µg?L^?1) in water. Health risk assessment of As showed that ADD (1.07E?02–9.85E?04), HQ (1.06E+01–9.85E+00), and CR (1.60E?02–9.85E?04) for oral exposure and ADD (1.03E?05–9.69E?06), HQ (1.19E?02–7.96E?03), and CR (1.11E?05–8.98E?05) for dermal exposure which were exceeded the toxic risk index value. Comparison of the two exposure pathways indicated that the oral exposure is much higher risk than the dermal contact. Both values of HI and CI were greater than WHO limit. It is concluded that residents of study area are at higher risk of As induced diseases and carcinogenicity.     

Human Health Risk from Metals in Fish from Saudi Arabia: Consumption Patterns for Some Species Exceed Allowable Limits

Fish are a healthful source of protein, but contaminants in some fish pose a risk. While there are multiple risk assessments from Europe and North America, there are far fewer for other parts of the world. We examined the risks from mercury, arsenic, lead, and other metals in fish consumed by people in Jeddah area, Saudi Arabia, using site-specific data on consumption patterns and metal levels in fish. The U.S. Environmental Protection Agency's Hazard Quotient (HQ) and cumulative Hazard Index (HI) for non-cancer endpoints and Carcinogenic Index for cancer were used to determine the health risk based on fish consumption rates. Of the 13 fish species examined, HQ was greater than 1 (indicating elevated risk) in two species for arsenic, and seven species for methylmercury. The cumulative HI for all metals was above 1 for all but three species of fish at the mean consumption rates. Generally, fish species with HI above 1 for one sampling location, had HI above 1 for all sampling locations. The implications of these findings are discussed in the light of strategies for reducing risk from fish consumption while encouraging dietary intakes of fish with low mercury and arsenic levels.     

污染场地土壤生态风险评估研究进展

随着我国快速城市化以及产业结构的调整,遗留下了大量的污染场地,发展和实施污染场地土壤生态风险评估是进行大规模污染场地修复行动的必要条件。本文围绕污染场地土壤生态风险评估的科学原理、框架构建及技术方法等方面的关键问题: 1)评估框架的场地实际针对性;2)概念模型的不确定性;3)土壤复合污染毒性机制;4)评估终点筛选;5)评估方法和框架构建等展开讨论,指出土壤复合污染的制毒机制,即污染物生物有效性和联合效应是污染场地土壤生态风险评估的关键科学问题。耦合美国环保局四步法和欧盟层级法的“证据-权重法”评估框架适用于野外复杂环境条件下的土壤污染生态风险评估。建议今后重点开展以下5个方面的工作: 1)污染场地土壤生态风险评估技术框架与风险管控技术框架之间的联合;2)概念模型研究;3)基于过程的场地土壤污染物反应运移模型研究;4)场地土壤复合污染生态毒理学机制研究;5)生态系统高水平生态风险评估终点研究。旨在为形成我国本土污染场地土壤生态风险评估技术指南提供理论基础和构架。     

Health Hazard Assessment of Pyridaben Residues in Egyptian Strawberries

Dissipation behavior and hazard assessment of the insecticide/acaricide pyridaben applied to strawberries were investigated under the climatic conditions of Egypt. A validated gas chromatographic method (GC-μECD) was used to determine pyridaben residues when applied at the recommended rate and twice this rate. The average recoveries were in the range between 95.8% and 103% with associated relative standard deviation not exceeding 14.5%. The estimated limit of quantification for pyridaben was 0.005 mg/kg. The field results showed that pyridaben dissipated rapidly in strawberries and had a half-life of approximately 2.3 days. The hazard assessment was evaluated by using the hazard quotient (HQ). The results showed that the HQ value was significantly less than HQ = 1. This result implied that the hazard of pyridaben use in strawberries even at double the recommended dosage was negligible to human. This study could provide guidance for the safe and reasonable use of pyridaben in strawberries and to prevent health problems to consumers; however, further hazard assessment studies are needed to ascertain the hazard of pyridaben residues on strawberries to vulnerable groups, including children, pregnant women, and elderly consumers.     

Human exposures and potential health hazard assessment of Hg and Pb in some major imported frozen fish species in Nigeria

The levels of mercury and lead in three major species of imported frozen fish—Atlantic mackerel (Scomber scombrus), sardine (Sardinella sindesis), and scumbera (Scumbria spp)—were determined and potential health hazard resulting from their ingestion by Nigerians was assessed. Sample digestion was carried out as prescribed in the Food and Agricultural Organisation/Swedish International Development Agency wet digestion method. Quantitation of the Hg and Pb content of the digested samples and blanks was carried out spectrophotometrically using thiozone as the ligand. The ranges of level of Hg in the samples in mg/Kg were: 0.03–0.42 for Scomber scombrus and 0.03–0.37 and 0.020–0.31 for Scumbria and Sardinella sindesis, respectively. Also, Pb had value ranges in mg/Kg of 0.20–0.28, 0.24–0.32, and 0.15–0.32 in Scomber scombrus, Scumbria, and Sardinella sindesis, respectively. Potential health hazard assessment that was carried out showed no risk status for children and adults consuming Sardinella sindesis and scumbera and adults consuming Scomber scombrus (HQ < 1). The results further showed a risk (HQ = 1.022 and THI = 1.036) for children taking Scomber scombrus.     

Bioaccessibility of heavy metals in rapa whelk Rapana venosa (Valenciennes, 1846): Assessing human health risk using an in vitro digestion model

Instead of total metal concentration measurements in seafood, bioaccessibility is a more important parameter for human health risk assessment. Therefore, bioaccessibility of Cd, Cr, Cu, Mn, Ni, Pb, and Zn in the edible soft tissues of rapa whelk (Rapana venosa Valenciennes, 1846) collected along the southern Black Sea coast were investigated using an in vitro digestion model. Zn was detected at the highest concentration, whereas Ni was the lowest for total metal concentrations. Total Cd and Pb concentration in the tissues were found to be higher than maximum permissible limits set by European Commission. The bioaccessibility of metals in the tissues was found to be decreased in the order: Cu (77.11%) > Cd (70.13%) > Zn (64.52%) > Ni (61.27%) > Pb (50.53%) > Cr (43.41%) > Mn (22.59%). While significant positive linear regressions were observed between the total and bioaccessible concentrations for Mn, Pb, and Ni, significant negative linear regressions were found for Cd in the tissues (p < 0.05). The hazard quotients (HQ) calculated using bioaccessible heavy metal amount were detected lower than the limit value (HQ < 1), which may not pose a potential hazard to humans declared by US Environmental Protection Agency. However, the consumption of rapa whelk may cause a potential risk concerning human health for the Cd and Pb levels in case of increased serving sizes and portions.     

Toxicological Considerations of Contaminants in the Terrestrial Environment for Ecological Risk Assessment

The terrestrial environment acts as a “sink” for contaminants that have been purposely or accidentally released into the environment. Science and policy that support protective measures for terrestrial ecosystems have run behind those of aquatic toxicology and water quality concerns. As a result ecological risk assessment (ERA) involving terrestrial environments tends to be conducted at a simplistic level, relying on numeric targets (soil quality criteria) as a basis for decision-making. However, soil criteria for ecological receptors are somewhat deficient in terms of the numbers available and the data that supports these numbers. Direct toxicity assessments (DTA) for terrestrial environments, such as those used for water quality evaluations, can provide additional useful information about the toxicity and bioavailability of mixtures of contaminants present in soils. This article outlines the approaches used for assessing the toxicity of soil contaminants in terrestrial environments and critiques their advantages and pitfalls.     

Issues in Ecological Risk Assessment of Inorganic Metals and Metalloids

Ecological risk assessment (ERA) is a process that evaluates the potential for adverse ecological effects occurring as a result of exposure to contaminants or other stressors. ERA begins with hazard identification/problem formulation, progresses to effects and exposure assessment, and finishes with risk characterization (an estimate of the incidence and severity of any adverse effects likely to occur). Risk management initially sets the boundaries of the ERA and then uses its results for decision-making. Key information required for an ERA includes: the emissions, pathways and rates of movement of contaminants in the environment; and, information on the relationship between contaminant concentrations and the incidence and (or) severity of adverse effects. Because of specific properties and characteristics of metals in general and of certain metals in particular, a generalized ERA process applicable to organic substances is inappropriate for metals. First, metals are naturally occurring and can arise, sometimes in very high concentrations, from non-anthropogenic sources; organisms can and do adapt to a wide range of metal concentrations. Second, certain metals (e.g., copper, zinc) are essential for biotic health, which means there is an effect threshold for both deficiency and excess, and that standard body burden indices such as bioaccumulation factors (BCFs) can be misleading. Third, metals can occur in the environment in a variety of forms that are more or less available to biota but adverse biological effects can only occur if metals are or may become bioavailable. Fourth, whereas the bioavailability and hence the possibility of toxicity of persistent organic substances are mainly dependent on their intrinsic properties (i.e., lipophilicity), those of metals are generally controlled by external environmental conditions. Examples include pH and ligands, which affect the metal speciation and coexisting cations (e.g., H⁺, Ca²⁺) which compete with the metal ions. ERAs involving metals must include the above four major considerations; other considerations vary depending on whether the ERA is for a site, a region, or is global in scope.     

基于生态系统服务的生态风险评价研究进展

生态风险评价对科学管理与保护生态系统具有重要的意义,为弥补传统生态风险评价方法的不足和提高风险管理的效率,将生态系统服务引入生态风险评价中进行发展和完善,成为了当前生态风险评价研究的前沿和热点。系统分析了生态系统服务在生态风险评价中的应用,指出生态系统服务在问题形成阶段中可明确保护对象和属性,在风险分析阶段可联系生态系统结构过程作用,在风险表征阶段及后续阶段能可提供清晰明确的评价结果,加强风险交流和管理,能有效地改进生态系统传统生态风险评价。在实践上,基于生态系统服务的生态风险评价可从3个不同层面开展:一是针对外界压力对某类特定功能或者系统中某些服务功能的影响,构建基于某种特定服务的实体属性评价方法;二是针对外界压力作用下生态系统结构与过程变化下对功能影响,构建基于复杂生态系统作用的评价方法,实现对生态风险的模拟评价;三是评价社会生态系统下外界驱动对人类福祉的影响时,可将DPSIR(Drive-Pressure-State-Impact-Response)理论模型运用到生态风险管理中,也可基于景观生态系统服务与压力源的空间作用关系,实现社会生态系统风险评价与管理。作为生态风险表征手段,可基于生态系统服务损失与不利服务进行表征,也可选取热力学等指标作为评估量纲。从理论、评价方法、风险管理等方面对基于生态系统服务生态风险评价给予展望。     

Preliminary Remediation Goals for Terrestrial Wildlife

Remediation of contaminated sites requires information on upper concentration limits of chemicals in environmental media that are protective of ecological receptors. These upper concentration limits can be considered ecological preliminary remediation goals (EcoPRGs). The motivation for developing EcoPRGs was to provide risk managers with a simple tool for evaluating remedial actions that would be protective of the environment. Hazard quotient calculations used to support ecological screening assessments were modified to derive soil EcoPRGs for terrestrial wildlife populations. The primary modification is a population area use factor that is the fraction of a terrestrial animal population potentially affected by the contaminated site. Wildlife assessment population boundaries are based on a receptor's dispersal distance; for mammals dispersal distance is strongly related to the linear dimension (square root) of home range. Assuming that wildlife are unlikely to disperse beyond some distance from their birth or natal site, dispersal distance can be thought of as the radius of the assessment population's boundaries. This general relationship is useful as a simple way to estimate assessment population areas for terrestrial animals and helps fill data gaps for wildlife without direct measurements of dispersal.     

生态风险研究述评

生态风险(ＥｃｏｌｏｇｉｃａｌＲｉｓｋ,ＥＲ),指一个种群、生态系统或整个景观的正常功能受外界胁迫,从而在目前和将来减小该系统健康、生产力、遗传结构、经济价值和美学价值的一种状况[20]。生态风险评估(ＥｃｏｌｏｇｉｃａｌＲｉｓｋＡｓｓｅｓｓｍｅｎｔ,ＥＲＡ)指受一个或多个胁迫因素影响后,对不利的生态后果出现的可能性进行的评估。美国环保局(ＥＰＡ)把这种尚不为人们所重视的领域叫做生态风险评估[20,48]。随着新技术和新方法的应用,ＥＲＡ的研究领域迅速扩展。早期的生态风险评估主要是针对人类健康而言的,也就是人类健康风险…     

Marsh wetland degradation risk assessment and change analysis: A case study in the Zoige Plateau,China

Wetlands play an important role in regional development and environmental protection. Under the impact of natural and artificial factors, the plateau wetlands have degenerated and even disappeared, resulting in serious problems for society and the ecological environment. It is necessary to establish a reasonable risk assessment method to evaluate the risk of wetland degradation, and then to analyze changes in the range and features of risk. For this work, the Zogie Plateau wetland was selected as the study area. For this site, a wetland degradation risk assessment method was established based on the conceptual model of Ecological Risk Assessment (ERA). The method included nine indicators used to analyze the wetland hazard index, wetland vulnerability index, and wetland degradation risk synthetically. From the spatial-temporal pattern, the wetland degradation risk was analyzed using data from 2000 to 2014. The calculated results revealed the following: (1) from 2000 to 2014, the wetland hazard index (WHI) showed a trend of increase, the value of which increased from 0.29 to 0.42, with a growth rate of 44.83%. Similarly, the wetland vulnerability index (WVI) significantly increased from 0.30 to 0.54, with a growth rate of 80%. Over the same time, the total wetland area decreased from 3910.25 km² to 2777.38 km², a reduction of 28.97%. (2) Using the equidistant method, the risk value was divided into three risk grades. The wetland degradation risk in the whole region is increasing, and the risk rank has changed from the low risk zone (0.092) to the medium risk zone (0.25). The degradation risk becomes greater with distance from the center to fringe areas.