Environmental Risk Assessment of Dams by Using Multi-Criteria Decision-Making Methods: A Case Study of the Polrood Dam,Guilan Province,Iran

A dam's construction always imposes some risks to the environment. In this article, the environmental risks of the Polrood dam, located in a northern province of Iran, during its construction phase, were identified, ranked, and evaluated. The risk factors were initially identified by Delphi questionnaire and then rated using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Subsequently, the Analytical Hierarchy Process (AHP) was applied to classify the risk factors into four major categories, and Expert Choice software was used to weight them. Based on the obtained results, Physicochemical; Biological; Economic, Social, and Cultural; and Health and Safety risks were rated by the weights of 0.124, 0.080, 0.048, and 0.021, respectively. Among the physicochemical risks, Erosion and Sedimentation weighted 0.061 and 0.047, respectively, were identified as the most serious risks. Among the biological risks, the highest negative impact was assigned to Land Cover with the weight of 0.189. In the third category, the most important risk was Population Displacement, weighted 0.114. Workers’ Falls with the weight of 0.109 was also determined as the highest risk in the last category. A comprehensive risk response plan will be required for dealing with the identified risks and their mitigation.     

A Novel Approach Toward Natural and Anthropogenic Risk Assessment of Gas Power Plants

The current study focuses on identification and prioritization of the most important risks affecting a gas power plant located in southern Iran that was selected as a case study. After identifying risky activities, plant operations, and natural disasters, a Delphi questionnaire was prepared to specify crisis and accident-prone centers that could lead to the plant's destruction. After analyzing the questionnaires, the final criteria were determined. Subsequently, multi-criteria decision-making methods including technique for order preference by similarity to ideal solution (TOPSIS) and analytical hierarchy process (AHP) were applied to prioritize the identified criteria. The relative weights of the criteria were calculated using the eigenvector method in the environment of MATLAB and EXPERT CHOICE. In some cases, there was no correlation between the obtained results, resulting in a novel integrated technique consisting of three methods: average, Borda, and Copeland was used to reach a consensus for prioritizing the criteria. The risk assessment results indicate that gas and oil pipes, dust storm, and terrorism have the first to third priorities among the other risks. Some strategies are proposed to control and mitigate the identified risks.     

A New Approach Toward Natural and Anthropogenic Risk Assessment of Gas Power Plants

The current study focuses on identification and prioritization of the most important risks affecting a gas power plant located in southern Iran that was selected as a case study. After identifying risky activities, plant operations, and natural disasters, a Delphi questionnaire was prepared to specify crisis and accident-prone centers that could lead to the plant's destruction. After analyzing the questionnaires, the final criteria were determined. Subsequently, multi-criteria decision-making methods including the technique for order preference by similarity to ideal solution (TOPSIS) and analytical hierarchy process (AHP) were applied to prioritize the identified criteria. The relative weights of the criteria were calculated using the eigenvector method in the environment of MATLAB and Expert Choice. In some cases, there was no correlation between the obtained results, resulting in a novel integrated technique consisting of three methods: average, Borda, and Copeland were used to reach a consensus for prioritizing the criteria. The risk assessment results indicate that gas and oil pipes, dust storm, and terrorism have the first to third priorities among the other risks. Some strategies are proposed to control and mitigate the identified risks.     

Fuzzy Multi-Objective Optimization of a Green Supply Chain Network with Risk Management that Includes Environmental Hazards

Among the leading environmental risks, global climate alteration has become one of the most important controversial issues. Greenhouse gas emissions (CO₂, methane, etc.) and air pollution have motivated a need to develop and improve environmental management strategies. As a consequence, environmental sanctions are forcing commercial enterprises to re-consider and re-design supply chain processes in a green way. This article provides a multi-objective model to design a closed-loop supply chain (CLSC) network in a green framework. Our first and second objectives are to minimize all the transportation costs for the supply chain's forward and reverse logistics; the third objective is to minimize total CO₂ emissions; the fourth objective is to encourage customers to use recyclable materials as an environmental practice. To provide more realistic modeling by treating the uncertainty in decision-makers’ objectives, fuzzy modeling is used in this study. The model is explained and tested via fulfilling a numerical example. In scenario analyses, analytic hierarchy process (AHP), fuzzy AHP (F-AHP), and fuzzy TOPSIS (F-TOPSIS) approaches were applied and compared to evaluate different objectives to guide decision-makers.     

Risk Assessment of Human Activities on Protected Areas: A Case Study

No study has been done on the impact of anthropogenic risks on protected areas. This may be due to complexity and diversity of risk assessment indices. In this research, using multicriteria decision-making methods, qualitative and complex indices were converted to simple and quantitative indices by which anthropogenic risks affecting the Helleh Protected Area in Iran were analyzed. To this end, a questionnaire was prepared and delivered to Delphi panelists consisting of environmental expertise. In order to prioritize the identified risks, Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), Analytical Hierarchy Process (AHP), and Simple Additive Weighting Technique (SAW) were used as a subset of Multiple Attribute Decision-making methods (MADM). In this study, risk factors were evaluated using three criteria of severity, probability of occurrence, and sensitivity of the recipient environment. In order to reach enough transcendence (consensus on priority of risks), an integrated approach comprising average, Borda, and Copeland methods was used. The obtained results suggested that “dam inundation upstream of the study area” is a top-priority risky factor threatening the wetland. “Stopping water pumps from the wetland” and “use of modern irrigation systems” were recommended as the most effective managerial strategies to control the identified risk.     

Safety,Health, and Environmental Risk Assessment of a Gas Power Plant: A Case Study from Southern Iran

This research was conducted to assess health, safety, and environmental risks of a gas power plant in southern Iran. In order to identify the subject risks of the power plant at operational phase a questionnaire was designed using the Delphi method. The questionnaires were put at the disposal of 99 electricity industry experts. Risk assessment was done using multicriteria decision-making methods such as technique for order of preference by similarity to ideal solution (TOPSIS), entropy, and Eigenvector technique. Following prioritization of risks at each power plant unit, top-priority risks were determined by one-way ANOVA. The obtained results indicated that the risk of working with medium voltage boards with a weight of 0.879 at the power plant's Electricity Unit is the most important safety and health risk in the studied power plant while risk of servicing the unit with fuel of gas weighting 0.807 and delivery of gas fuel with weight of 0.630 in the Exploiting Unit and work on liquid fuel clutch with weight of 0.603 in the Mechanical Unit are the most important environmental risks in the gas power plant. In conclusion, this study concludes that health, safety, and environmental risk assessment can be a structured and used as a systematic approach to plan for environmental protection and personnel health.     

Integrated environmental risk assessment approach for transportation modes

Abstract

The main aim of this study is to develop and implement new integrated environmental risk assessment for transportation activities. With this purpose, environmental risks occur from transportation activities from different transportation modes which are air, road, sea and rail are determined. Transportation modes are compared with the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) approach in order to obtain importance weights and impact categories of air, soil and water are used as criteria where the weights are determined with Analytical Hierarchy Process (AHP). For the risk assessment process, Failure Mode and Effect Analysis (FMEA) has been used and prioritizations of risks are calculated with weights of the calculated transportation modes. In the study, integrated multi-criteria decision-making methods with the classic FMEA method with different categories of impacts reveal new multidimensional perspective to classic environmental risk assessment methods.     

TOPSIS-Based Screening Method of Soil Remediation Technology for Contaminated Sites and its Application

A soil remediation technology screening system has not yet been established in China, and the existing supporting conditions for soil remediation technology cannot meet the supervision needs of contaminated sites’ remediation. Considering the soil remediation technology screening methods for contaminated sites in developed countries and the supervision requirements of contaminated sites in China, this article briefly introduces the main characteristics of decision-making methods, and the screening indices, including technical, economic, social, and environmental factors, are suggested. The technique for order performance by similarity to ideal solution (TOPSIS) was used to establish a screening process for soil remediation technology, and the analytic hierarchy process (AHP) method was utilized to obtain the weights of the screening indices. Tthe suggested screening method was then applied in a chromite ore-processing residue site in China, and suitable remediation technology (in-situ chemical reduction-oxidation) was proposed. The research results could provide scientific and technological support for the supervision of contaminated sites in China.     

Environmental risk assessment of dams at constructional phase using VIKOR and EFMEA methods (Case study: Balarood Dam,Iran)

Abstract

The purpose of this study was to assess the environmental risk of Balarood Dam in Iran at constructional phase. The scientific methods used in this research were the Environmental Failure Mode and Effects Analysis (EFMEA) and VIKOR. In the process of environmental risk assessment, the EFMEA method was used first to calculate the risk priority number (RPN) for each environmental aspect. The identified risks were ranked based on RPN values in the next stage. Comparison of the RPN values showed that the risk of pollution of Balarood River, with a RPN of 125, is in the first priority. In addition, the environmental risks, identified during the follow-up phase, were weighted by entropy method based on severity, occurrence probability, and extent of pollution.Then, the VIKOR method, as one of the multicriteria decision-making (MCDM) methods, was run to evaluate and prioritize the potential environmental risks. The risk of water pollution under high, medium and low conditions, with a weight of 1,300, 1,000 and 700, was identified as the most important risk of dam construction. Accordingly, the most important corrective action, proposed to mitigate the high priority environmental risks, is to prevent the discharge of sanitary and industrial wastewater into the river.     

Effect of product recovery and sustainability enhancing indicators on the location selection of manufacturing facility

The inclusion of economical, environmental, and societal issues in all stages of doing business helps to bring about sustainable development. A business begins or expands by establishing new facilities, so selecting a facility location is a strategic and crucial decision. In the context of sustainability, the selection of location for different facilities can be a critical problem, especially for manufacturing firms that endorse the wide footprint of Extended Producer Responsibility policies. This study aims at prioritizing alternative potential locations for manufacturing firms with respect to the three dimensions of sustainability identified above. The three dimensions are assessed by factors obtained through a factor analysis and are grouped by corresponding invariable sub criteria. These sub criteria are chosen from the extant literature review. Then, the preferred order of alternative potential location is obtained by Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) based on each location's overall performance. The performance of each alternative potential location is assessed on the basis of overall weights of alternatives, evaluating factors, and triple bottom line attributes, which were obtained by Analytical Hierarchical Process (AHP). The multi criteria decision making technique, AHP, calculates the weights of the qualitative and quantitative criteria impacting the location selection problem. Then the approach of the study is validated by applying a case from real life; the results are justified by completing a sensitivity analysis on the relative importance weights of the three primary attributes (economical, environmental, and social). The results of the sensitivity analysis demonstrate an effective decision making technique for the optimal selection of sustainable manufacturing locations.     

Evaluating Environmental Performance of Pulp and Paper Manufacturing Using the Analytic Hierarchy Process and Life-Cycle Assessment

This article addresses the need for a structured and compre-hensive methodology for assessing the environmental perfor-mance of manufacturing processes. The analytic hierarchy pro-cess (AHP) is used as the basic framework for analyzing environmental impacts and improvement options following a streamlined life-cycle assessment (LCA) approach that is fo-cused on the manufacturing operation. The multicriteria de-cision analysis approach of the AHP is consistent with the LCA concept because the environmental factors can be hierarchi-cally structured into impacts and improvement options. Its po-tential as a valuation tool for impact and improvement assess-ment addresses both qualitative and quantitative issues in environmental decision making.
Through application to a pulp and paper manufacturing case study, the viability of the AHP for evaluating environmen-tal impacts and prioritizing process improvement options rela-tive to these impacts is demonstrated. AHP was used to pro-vide a quantitative tool for the design of a set of weighting factors for impact and improvement analyses.     

Dynamic successive assessment method of water environment carrying capacity and its application

Water environment carrying capacity (WECC) is an important foundation of sustainable socioeconomic development and may be affected by many factors such as water resources, water quality, economy, population and environmental protection. This article focuses on the temporal and spatial variability of WECC to explore a method of dynamic successive assessment. First, the Pressure-State-Response (PSR) framework is used to develop a systematic and causal indicator system representing the three aspects of water environment pressure carrying capacity (WEPCC), water environment state carrying capacity (WESCC) and water environment response carrying capacity (WERCC). The Variable Fuzzy Pattern Recognition (VFPR) model and an analytic hierarchy process (AHP) model are combined to successively and dynamically assess WEPCC, WESCC and WERCC, and after that the weighting method is used to calculate WECC. Furthermore, WECC is divided into 27 classes on the basis of WEPCC, WESCC and WERCC contributions. The proposed method is applied to the dynamic successive assessment of WECCs in China, including inter-province comparisons. The results show that the dynamic successive WECC assessment method is reasonable, and it can be used not only to accurately understand the changes of WECC through time but also to distinguish qualitative differences masked by similar WECC values.     

A method for determining weights for excess relative risk and excess absolute risk when applied in the calculation of lifetime risk of cancer from radiation exposure

Radiation-related risks of cancer can be transported from one population to another population at risk, for the purpose of calculating lifetime risks from radiation exposure. Transfer via excess relative risks (ERR) or excess absolute risks (EAR) or a mixture of both (i.e., from the life span study (LSS) of Japanese atomic bomb survivors) has been done in the past based on qualitative weighting. Consequently, the values of the weights applied and the method of application of the weights (i.e., as additive or geometric weighted means) have varied both between reports produced at different times by the same regulatory body and also between reports produced at similar times by different regulatory bodies. Since the gender and age patterns are often markedly different between EAR and ERR models, it is useful to have an evidence-based method for determining the relative goodness of fit of such models to the data. This paper identifies a method, using Akaike model weights, which could aid expert judgment and be applied to help to achieve consistency of approach and quantitative evidence-based results in future health risk assessments. The results of applying this method to recent LSS cancer incidence models are that the relative EAR weighting by cancer solid cancer site, on a scale of 0–1, is zero for breast and colon, 0.02 for all solid, 0.03 for lung, 0.08 for liver, 0.15 for thyroid, 0.18 for bladder and 0.93 for stomach. The EAR weighting for female breast cancer increases from 0 to 0.3, if a generally observed change in the trend between female age-specific breast cancer incidence rates and attained age, associated with menopause, is accounted for in the EAR model. Application of this method to preferred models from a study of multi-model inference from many models fitted to the LSS leukemia mortality data, results in an EAR weighting of 0. From these results it can be seen that lifetime risk transfer is most highly weighted by EAR only for stomach cancer. However, the generalization and interpretation of radiation effect estimates based on the LSS cancer data, when projected to other populations, are particularly uncertain if considerable differences exist between site-specific baseline rates in the LSS and the other populations of interest. Definitive conclusions, regarding the appropriate method for transporting cancer risks, are limited by a lack of knowledge in several areas including unknown factors and uncertainties in biological mechanisms and genetic and environmental risk factors for carcinogenesis; uncertainties in radiation dosimetry; and insufficient statistical power and/or incomplete follow-up in data from radio-epidemiological studies.     

环境足迹的核算与整合框架——基于生命周期评价的视角

环境足迹及其与生命周期评价(LCA)的关系是工业生态学关注的新热点。从探讨环境足迹与LCA的关系入手,以碳足迹、水足迹、土地足迹和材料足迹为例,分别对每一项足迹指标两个版本的核算方法进行了比较。根据清单加和过程的特点,将所有足迹指标划分为基于权重因子和基于特征因子两类,总结了两者的适用性和局限性。在此基础上提出了一个环境足迹核算与整合的统一框架。该框架基于LCA视角建立,但对系统边界和清单数据的要求相对灵活,因而也适用于生命周期不甚明确的情形。研究在一定程度上揭示了足迹指标的方法学实质,同时也为环境影响综合评估提供了一条规范化的途径。     

Impact of normalisation,elicitation technique and background information on panel weighting results in life cycle assessment

Purpose

Weighting in Life Cycle Assessment (LCA) is a much-debated topic. Various tools have been used for weighting in LCA, Multi-Criteria Decision Analysis (MCDA) being one of the most common. However, it has not been thoroughly assessed how weight elicitation techniques of MCDA with different scales (interval and ratio) along with external and internal normalisation affect weighting and subsequent results. The aim of this survey is to compare different techniques in an illustrative example in the building sector.

Methods

A panel of Nordic LCA experts accomplished six weighting exercises. The different weight elicitation techniques are SWING which is based on the interval scale; Simple Multi-Attribute Rating Technique (SMART) and Analytic Hierarchy Process (AHP) which is based on the ratio scale. Information on the case study was provided for the panellists, along with characterised or normalised impact assessment scores. However, in the first weighting exercise, the panellists were not provided with any scores or background information, but they had to complete the weighting at a more general level. With the weights provided by the panel, the environmental impacts of three alternative house types were aggregated. The calculations were based on three well-grounded aggregation rules, which are commonly used in the field of LCA or decision analysis.

Results and discussion

In the illustrative construction example, the different aggregation rules had the biggest impact on the results. The results were different in the six calculation methods: when externally normalised scores were applied, house type A was superior in most of the calculations, but when internal normalisation was accomplished, house type C was superior. By using equal weights, similar results were obtained. None of the panellists intuitively considered A as the superior house type, but in some of the calculations, this was indeed the case. Furthermore, the results refer to the fact that the panellists completed the weighting on the basis of their general knowledge, without taking the features of different weight elicitation techniques into account.

Conclusions

External normalisation provides information on a magnitude of impacts, and in some cases, external normalisation may be a more influential factor than weighting. Based on the results, it cannot be stated which different weight elicitation technique is the most suitable for LCA. However, the method should be selected based on the aims and purpose of the study. Moreover, the elicitation questions should be explained with care to experts so that they interpret the questions as intended.     

Composite Subsidence Vulnerability Assessment Based on an Index Model and Index Decomposition Method

The threat of damage to buildings and other infrastructures resulting from land subsidence associated with groundwater pumping in urbanized areas is an ongoing problem requiring assessment. An important goal of subsidence vulnerability assessment is to construct a composite subsidence vulnerability index (SVI) that is represented by a set of indicators that focuses on four different thematic factors: physical, social, economic, and environmental vulnerability. These indicators are evaluated on the basis of indicator selection principles and then weighted by their contribution rate to the overall index. The weights reflect different measures assigned to the township-specific conditions. A complete and composite subsidence vulnerability assessment is developed in which future vulnerability management decision-making processes can be readily made. The vulnerability assessment includes not only the construction of the SVI, which involves selecting, assigning value to, weighting, and aggregating the vulnerability indicators, but also the presentation of the SVI decomposition. Research results demonstrate that a composite subsidence vulnerability assessment method can be made by first constructing and then decomposition-presenting the overall SVI. This allows for the relative comparison of subsidence vulnerability and the identification of the main vulnerable indicators; thus providing subsidence risk, which represents an important step toward vulnerability management of water resources.     

基于物种运动路径识别的动物通道选址——以武深高速为例

动物通道是缓解高速公路对其周边野生动物生境隔离的有效措施,通道的位置是影响其使用效率的关键因素,然而现有研究对通道的选址却甚少涉及。以武深高速为例,推荐一种基于物种运动路径识别的通道选址方法,选取影响动物生境选择的环境因子构建评价体系,借助GIS手段对公路周边野生动物生境适宜性进行分析,在此基础上借鉴水文分析原理快速准确地刻画出物种在生境中的潜在活动路径,从而确定了5处高速公路上建设动物通道的理想位置。结果表明,该方法能定量地反映出生境的质量格局对于物种运动的影响,准确定位出物种运动受到阻碍的关键区域,在景观层次上,提出的通道位置能有效地缓解栖息地破碎化造成的生态压力;研究不但能弥补目前研究的不足,同时亦为道路网设计、城市生态规划等相关领域研究提供科学参考。     

Development of weighting factors for G20 countries—explore the difference in environmental awareness between developed and emerging countries

Purpose

Weighting is one of the steps involved in LCIA. This enables us to integrate various environmental impacts and facilitates the interpretation of environmental information. Many different weighting methodologies have already been proposed, and the results of many case studies with a single index have been published. LIME2 (Itsubo et al. Int J Life Cycle Assess 17(4):488-498, 2012) developed weighting factors for four different areas of protection that reflect environmental awareness among the Japanese public. This method has already been widely used in Japan, but difficulties exist universally using the Japanese weighting factors around the world. It is presumed that the weighting varies depending on economic, cultural, and social conditions, and there are still few cases in which weighting factors have been specifically invented or studied in consideration of variance in these elements. This study attempted to develop weighting factors applicable to the Group of Twenty (G20) countries with a view toward developing those that could be used in different countries. In the study, a survey was conducted with a uniform questionnaire in G20 countries to compare the weighting factors calculated for different countries, along with an investigation on development and utilization of global weighting factors.

Methods

A conjoint analysis was conducted to give a weighting between the four areas of protection defined by LIME: human health, social assets, biodiversity, and primary production. The analysis is suitable for measuring the value of each of the multiple attributes of the environment. This study conducted a questionnaire in all the G20 member states. The survey puts priority on making the questions understood by the respondents and minimizing bias, adopting interviews, visiting surveys, and surveys in venues in the 11 emerging countries. In the developed countries, Internet surveys were conducted after confirming that their results are statistically significant from the pretest results in these states. In both surveys, random sampling was performed to take 200–250 samples (households) in each of the emerging countries and 500–600 samples in each of the developed countries. The surveys collected a total of 6400 responses. Statistical values based on this model can be considered to reflect the variability between each individual’s environmental thoughts. The calculated results can then be used to compare the variety of environmental thoughts in developed and emerging countries.

Results and discussion

The study was able to obtain two different kinds of results: dimensionless weighting factors and economic indicators using the amount of willingness to pay. This paper solely presents the former. The weighting factors in the entire G20 community, in the group of developed countries (G8) and in the group of emerging countries (G20 states excluding the G8) and those in the individual G20 countries, were estimated. The calculated values were significant statistically at the 1 % level (all p values for the safeguard subject coefficients were less than 0.0001), with the exception of monetary attributes for several emerging countries. Converted into dimensionless values, so that the total sum for the four subjects equals 1, the weighting factor was the highest for human health in the entire G20 circles, at 0.34, followed by biodiversity at 0.29, and primary production at 0.23. The weighting for social assets was relatively poor, at 0.13. In the G8 developed states, the figures of biodiversity and primary production were relatively higher than those of the same two subjects in the full G20. Biodiversity had the highest value, at 0.34, and was followed by human health at 0.30. On the other hand, in emerging countries, the weighting of health impacts was particularly significant, at 0.44, whereas the three other subjects had almost equivalent weightings—biodiversity at 0.19, social assets at 0.18, and primary product at 0.18. The weighting factors by country and the variance of preference intensities by country showed minor differences among developed countries while they reflected considerable differences among emerging countries.

Conclusions

Accurate weighting factors representing the environmental attitudes of the world and national public are needed in order to conduct general purpose LCA. This study is the world’s first to conduct surveys with the use of the same questionnaire not only in developed countries but also in emerging countries, and to compare the findings. A total of 6400 responses were obtained via interviews and Internet surveys. The survey thus gained a statistically significant result on all the environmental attributes including the weighting factors for the G20 circles, G8 states, emerging countries exclusive of the G8 states, and individual countries in which surveys took place. The results have revealed a relatively minor difference in weighting factors and variation coefficients between the areas of protection in the developed countries whereas a considerable difference was observed between those subjects in emerging countries.

     

Integrating Multiple Toxicological Endpoints in a Decision-Making Framework for Contaminated Sediments

Contaminated sediment has been identified as one of the major impediments to ecosystem restoration, but there has been little progress made in the management of sediment contaminants. Four primary lines of evidence are generally required for informed assessments yet the integration of these various lines of evidence is problematic. Using data from 220 reference sites located in the nearshore zone of the Laurentian Great Lakes the normal response of four species of laboratory organisms to sediments representing a wide range of sediment characteristics was examined. The toxicity data from the reference sites were used to establish categories of responses to test sediments. The delineations for the three categories were developed from the standard statistical parameters of population mean and standard deviation (mean ± SD) of an endpoint measured in all reference sediments. Three approaches for integrating information were examined; the first two are score based, the third approach uses a multivariate statistical method to integrate the responses. The methods were examined using both artificial and real test site data and from this it was concluded that ordination is the superior of the three. It is the least subjective within the context of the integration of the endpoints, is quantitative, and also provides appropriate weighting based on the variation observed within reference sites.     

EFFECTS OF AN OFFSHORE OIL DEVELOPMENT ON LOCAL ABUNDANCE AND DISTRIBUTION OF RINGED SEALS (PHOCA HISPIDA) OF THE ALASKAN BEAUFORT SEA1

This study investigates how densities of ringed seals were affected by construction and oil production activities at Northstar, an artificial island built in the nearshore Alaskan Beaufort Sea. Intensive and replicated aerial surveys of seals on landfast ice were conducted during six spring seasons: for three seasons before island construction began (1997–1999); after a winter of intensive island construction (2000); and after more limited construction plus drilling (2001) and drilling plus oil production (2002). A Poisson regression model was used to examine seal densities relative to distance from Northstar after allowance for environmental covariates. Post hoc power analysis indicated that the study design and Poisson regression approach had high power to detect small‐scale changes in seal densities near Northstar if such changes had occurred. However, seal densities during spring were not significantly affected by proximity to Northstar in 2000–2002. Habitat, temporal, and weather factors did have significant effects on seal densities. This study shows that effects of the Northstar oil development on local distribution of basking ringed seals are no more than slight, and are small relative to the effects of natural environmental factors. An understanding of environmental effects is essential when assessing potential impacts of industrial activity on ringed seals.