Environmental Impact, Risk and Life-Cycle Assessment

Introduction and context

Civil engineering projects transform land, water, energy systems and communities. A highway changes drainage and habitat patterns; a dam alters sediment transport and livelihoods; a wastewater plant consumes energy while reducing pollutant discharge; and a building generates impacts from material extraction through demolition. Environmental assessment therefore extends beyond checking whether an individual facility meets an emission limit. It asks whether a proposal is needed, which alternative is preferable, who bears the costs and benefits, what risks are acceptable, and how impacts accumulate over time.

This chapter presents an integrated framework for environmental impact assessment (EIA), social impact assessment (SIA), alternatives analysis, cumulative-impact evaluation, quantitative risk assessment (QRA), life-cycle assessment (LCA), and cost–benefit analysis (CBA). These tools are related but not interchangeable. EIA is primarily a decision and management process; QRA estimates the likelihood and consequences of hazardous events; LCA evaluates environmental burdens across a product or project life cycle; and CBA compares monetised benefits and costs, subject to important ethical and distributional limitations.

The professional task is not simply to produce a larger report. It is to develop credible evidence, expose uncertainty, engage affected people, compare realistic alternatives, and establish enforceable commitments. Good assessment is consequently both technical and institutional.

Learning objectives

After completing this chapter, a student should be able to:

1. Explain the purposes, stages and decision logic of EIA and SIA.

2. Define baseline conditions, impact significance, alternatives and cumulative impacts.

3. Apply screening, scoping, prediction, mitigation hierarchy and monitoring principles.

4. Conduct a basic quantitative risk assessment using frequency, probability and consequence.

5. Explain LCA goal and scope, functional units, system boundaries, inventories and impact interpretation.

6. Distinguish LCA from project EIA and CBA and select an appropriate combination of tools.

7. Apply discounted cash-flow and expected-value concepts in environmental CBA.

8. Critically evaluate uncertainty, equity, governance, ethical issues and emerging digital methods.

1. Environmental assessment as a decision framework

1.1 Environmental impact assessment

EIA is a systematic process for identifying, predicting, evaluating and managing the biophysical and social consequences of a proposed action before an irreversible decision is made. It normally includes legal screening, scoping, baseline studies, alternatives analysis, impact prediction, mitigation planning, public participation, decision-making, monitoring and audit.

A useful distinction is between an impact and a pressure. A pressure is a project action or emission, such as land clearing, abstraction or particulate release. An impact is the resulting change in an environmental or social receptor, such as habitat fragmentation, reduced river flow or respiratory exposure. A receptor is a valued environmental component, community, group or asset that may be affected.

EIA should be initiated early enough to influence project location, technology, scale and timing. If it begins after the design is effectively fixed, it becomes a compliance exercise rather than an alternatives-led decision process.

1.2 Social impact assessment

SIA examines effects on people, households, institutions, culture, livelihoods, health, access, identity and social relationships. It includes both adverse and beneficial effects. Distribution is central: an aggregate benefit may coexist with severe losses for a small, politically weak community. SIA should therefore identify vulnerable groups, gendered effects, Indigenous or customary rights, informal users, displaced people and workers, rather than treating the affected population as homogeneous.

Social impacts may be direct, indirect or induced. A reservoir may directly inundate land, indirectly affect downstream fisheries, and induce migration and new settlement. Some impacts are tangible and measurable; others, such as loss of cultural meaning, cannot be adequately represented by market prices.

1.3 Strategic and cumulative assessment

Project EIA evaluates a defined proposal. Strategic environmental assessment (SEA) considers policies, plans and programmes before individual projects are selected. It can prevent environmentally unsuitable development pathways and examine alternatives at a scale where major choices remain open.

Cumulative impact assessment (CIA) examines the combined effects of the proposal with past, present and reasonably foreseeable actions. Cumulative effects may be additive, synergistic, compensatory or threshold-based. For example, several individually compliant abstractions can collectively reduce a river below an ecological flow requirement. CIA requires a meaningful spatial and temporal boundary, a valued-component focus, and knowledge of other activities—not merely a longer list of project impacts.

2. The EIA process and analytical foundations

Screening and scoping

Screening determines whether assessment is required and at what level. Criteria commonly include project type and scale, sensitivity of the location, likely pollution, resource use, displacement and potential for significant or irreversible effects. Screening should avoid both under-assessment of risky small projects and over-assessment of routine low-risk activities.

Scoping establishes what matters, which alternatives will be assessed, the geographic and temporal boundaries, methods, stakeholders, data needs and significance criteria. A scoping report or terms of reference should be specific enough to prevent omission but flexible enough to accommodate evidence discovered during the study. Stakeholder participation is most valuable at scoping because it can identify local knowledge, seasonal uses, cultural sites and issues invisible in desktop data.

Baseline and counterfactual conditions

A baseline is not merely a collection of present measurements. It is a defensible description of environmental and social conditions and their trends in the absence of the proposal. The relevant comparison is often a future without project scenario, not a static current condition. Baseline surveys should address seasonal variability, spatial heterogeneity, data quality and existing pressures.

The with-project scenario predicts conditions under each alternative. Impact is conceptually the difference between the with-project and without-project conditions, although attribution may be difficult when climate change, urbanisation and other developments occur simultaneously. Monitoring design should preserve this distinction and, where possible, use reference sites, before–after comparisons or control-impact designs.

Impact pathways and significance

An impact pathway links source, pathway, receptor and consequence:

Source or activity → emission or disturbance → transport or exposure pathway → receptor → environmental or social consequence.

Significance is a professional judgement supported by evidence. Common dimensions include magnitude, extent, duration, reversibility, likelihood, sensitivity or value of the receptor, legal standards and stakeholder concern. A small change in a highly sensitive wetland may be more significant than a larger change in a resilient, already degraded area.

Significance matrices are useful communication devices but should not conceal assumptions. A matrix that multiplies arbitrary scores is not automatically quantitative. Where values are ordinal, mathematical operations such as averaging may be unjustified. Significance criteria should be transparent, justified and, where possible, linked to regulatory thresholds, ecological limits or socially established objectives.

Mitigation hierarchy

The preferred sequence is:

1. Avoid impacts through no-go areas, alternative locations, timing or project cancellation.

2. Minimise impacts through design, construction controls, efficient resource use and pollution prevention.

3. Restore or rehabilitate affected environments.

4. Offset or compensate residual, significant impacts only where technically feasible, measurable and ethically acceptable.

Offsets should not legitimise avoidable damage or the destruction of irreplaceable biodiversity and cultural heritage. A mitigation commitment should specify location, performance standard, responsible party, schedule, financing, monitoring indicator and corrective action.

Monitoring, management and audit

Environmental management plans convert predictions into responsibilities and controls. Monitoring should be hypothesis-driven: each indicator must relate to a predicted impact, a compliance requirement or an adaptive-management decision. Monitoring without action thresholds is data collection, not management. Environmental audits compare actual performance with approval conditions and predictions; they can reveal model bias, unforeseen effects and non-compliance.

3. Alternatives analysis and decision quality

Alternatives are the core of assessment. They may include demand management, different locations, alignments, scales, technologies, construction methods, operating regimes, timing, ownership arrangements and the no-project or do-minimum option. An alternative that is technically impossible or legally unavailable should not be presented as a serious option merely to make the preferred proposal appear favourable.

A defensible alternatives process follows these steps:

• Define the problem and service need independently of a favoured technology.
• Establish screening constraints, such as safety, land availability and minimum service performance.
• Generate a broad longlist, including non-build and nature-based options.
• Compare feasible options using consistent environmental, social, technical, economic and risk criteria.
• Document trade-offs, uncertainty and reasons for rejection.
• Revisit alternatives when new evidence changes the decision.

Multi-criteria analysis (MCA) can support comparison where effects cannot all be monetised. A simple weighted additive model is

S_j = Σ(w_i x_{ij}),

where S_j is the score of alternative j, x_{ij} is its normalised performance on criterion i, and w_i is the weight assigned to criterion i. The weights should be explicit, and the normalisation direction must be consistent (for example, higher emissions should receive a lower performance score). This model assumes compensability: a poor result on one criterion can be offset by good results on another. That assumption may be unacceptable for legal rights, safety limits or critical ecological thresholds. Sensitivity testing of weights and scores is therefore essential.

4. Quantitative environmental and social risk assessment

4.1 Risk concepts

Risk is commonly described as a combination of the likelihood of an event and its consequences. Hazard is the potential to cause harm; exposure describes contact with the hazard; vulnerability describes susceptibility; consequence is the resulting loss or harm. Risk assessment should distinguish uncertainty about the world from variability in real conditions. For example, uncertain toxicity data differ from naturally varying rainfall or population exposure.

A basic risk register identifies hazard, initiating event, pathway, receptor, consequence, existing controls, likelihood, severity, residual risk, owner and review date. Qualitative matrices are useful for prioritisation but are vulnerable to coarse categories, inconsistent scoring and false precision.

4.2 Quantitative risk

For discrete mutually exclusive scenarios, expected annual loss may be represented as

EAL = Σ(p_i C_i),

where p_i is the annual probability of scenario i and C_i is its consequence expressed in a common unit, such as monetary loss or fatalities. This is an expected value, not a prediction of the exact annual outcome. It is valid only when the scenarios are defined consistently and probabilities and consequences are estimated on compatible bases.

If an event occurs as a Poisson process with constant annual rate λ, the probability of at least one event in a period t is

P(N ≥ 1) = 1 − exp(−λt).

Here λ is measured in events per unit time and t uses the same time unit. The model assumes independent events and a constant rate; changing climate, ageing infrastructure or learning effects may violate these assumptions.

For health risk, a simplified individual lifetime excess risk can be expressed as the product of an average daily dose and a route-specific risk coefficient, subject to the coefficient’s units and applicable exposure assumptions. Such calculations must use authoritative toxicity values and must not combine incompatible regulatory databases. Non-cancer hazard quotients are often calculated as estimated exposure divided by a reference dose, but a quotient below one is not proof of zero risk and a quotient above one is not by itself a diagnosis of harm.

4.3 Risk treatment and communication

Risk reduction follows a hierarchy similar to mitigation: eliminate the hazard, substitute, engineer controls, administrative controls, and personal protective equipment. ALARP or similar principles require risks to be reduced as far as reasonably practicable, while legal tolerability criteria may define non-negotiable limits. Emergency planning should address credible worst cases, warning systems, evacuation, communication, vulnerable populations and recovery.

Risk communication must state what is known, what is uncertain, the time horizon, the affected population and the comparison being made. Presenting only a single number can mislead decision-makers; ranges, scenarios and sensitivity analysis are usually more informative.

5. Life-cycle assessment

5.1 Purpose and scope

LCA evaluates environmental inputs, outputs and potential impacts throughout a defined life cycle. It can be applied to materials, products, infrastructure systems or services. A project EIA is location-specific and focuses on effects of a proposed activity; LCA is system-oriented and can compare supply chains even when impacts occur in different countries. LCA may therefore reveal upstream burdens, such as cement production or steel manufacture, that a site EIA would not fully capture.

The four interrelated LCA phases are:

1. Goal and scope definition.

2. Life-cycle inventory analysis (LCI).

3. Life-cycle impact assessment (LCIA).

4. Interpretation.

The functional unit quantifies the service being compared, such as “one passenger-kilometre,” “one cubic metre of treated water meeting a specified quality,” or “one square metre of road providing a defined service for 30 years.” Comparing one tonne of two materials without ensuring equivalent function can produce a misleading result.

The system boundary determines included processes: raw-material extraction, manufacturing, transport, construction, operation, maintenance, end-of-life and possible recycling or reuse. Capital equipment, land-use change, infrastructure and user behaviour should be included or excluded deliberately and documented. Cut-off rules should not remove small but collectively important flows.

5.2 Inventory, allocation and impact assessment

An LCI records energy and material inputs and emissions to air, water and land for each unit process. Data may be measured, modelled, database-derived or estimated. Data quality should be assessed for time, geography, technology, completeness and uncertainty.

When a process produces multiple products, burdens may need allocation. Preferred approaches often include subdivision or system expansion; allocation by mass, energy or economic value is used when alternatives are not feasible. The selected method can materially change results and should be tested through sensitivity analysis.

LCIA converts inventory flows into impact indicators. Examples include climate change, acidification, eutrophication, photochemical ozone formation, particulate matter, water scarcity and resource use. Characterisation factors express the relative contribution of substances to a category; results across categories should not be casually added because they represent different environmental mechanisms. Normalisation and weighting can aid interpretation but introduce value judgements.

LCA is not a direct measure of local ecological damage. A global warming result does not describe exactly where habitat is lost, and generic water-scarcity factors may not represent a particular catchment. LCA should therefore complement, not replace, site-specific EIA and ecological assessment.

5.3 Interpretation and uncertainty

Interpretation identifies significant processes, checks completeness and consistency, tests sensitivity, and draws conclusions consistent with the goal and scope. Common uncertainties arise from parameter data, model structure, future operating conditions, recycling assumptions and allocation choices. Scenario analysis is particularly important for infrastructure with long lives. A result is robust only if the preferred option remains favourable across credible assumptions.

For a simple carbon comparison, total life-cycle emissions may be estimated as

E_total = E_materials + E_transport + E_construction + E_operation + E_maintenance + E_end-of-life − E_credits,

where each term is expressed in a consistent unit such as kilograms of CO₂-equivalent. This is an accounting framework, not a universal law. Credits for recycling or avoided products must avoid double counting and clearly state the reference product and substitution assumption.

6. Environmental cost–benefit analysis

CBA compares benefits and costs over time in monetary terms. It is useful for prioritising public investments but cannot by itself resolve rights, ecological limits or distributional justice. Monetisation methods include market prices, avoided costs, replacement costs, stated preference and revealed preference. Results depend on the chosen social discount rate, valuation assumptions and treatment of uncertainty.

The present value of a future amount X_t received or paid at year t is

PV_t = X_t/(1+r)^t,

where r is the discount rate per period. Net present value is

NPV = Σ_{t=0}^{T} (B_t − C_t)/(1+r)^t,

where B_t and C_t are benefits and costs in year t, T is the analysis horizon, and all monetary values are in the same price basis. A positive NPV indicates that monetised benefits exceed monetised costs at the selected discount rate; it does not prove that every group benefits.

Environmental projects often have long-term benefits and irreversible losses. A high discount rate can sharply reduce the present value of distant climate or ecosystem benefits. Analysts should report sensitivity to discount rates, include distributional effects, and consider safe-minimum standards or multi-criteria decisions where monetisation is ethically or technically inappropriate. Risk-adjusted analysis may use expected values, scenario ranges or Monte Carlo simulation, but simulation quality depends on defensible input distributions and correlations.

7. Integrated assessment workflow

A robust project assessment can be organised as follows:

1. Define the service need, decision authority, legal framework and affected rights-holders.

2. Screen the proposal and establish an interdisciplinary team.

3. Scope valued components, alternatives, boundaries, methods and participation arrangements.

4. Develop a baseline and future-without-project scenario.

5. Identify impact pathways, hazards, life-cycle stages and cumulative pressures.

6. Predict impacts using appropriate physical, ecological, social and risk models.

7. Compare alternatives using thresholds, MCA, LCA, QRA and CBA as appropriate.

8. Apply the mitigation hierarchy and design an environmental and social management plan.

9. Disclose uncertainty, residual impacts, compensation and grievance mechanisms.

10. Obtain a decision with enforceable conditions, then monitor, audit and adapt.

Integration should occur at the decision level. For example, LCA may favour a recycled material because of lower embodied emissions, while local EIA may identify toxic leaching or water scarcity at the proposed site. The correct response is not to select one tool as universally superior, but to investigate the conflict, improve the design and make the trade-off explicit.

8. Illustrative case: alternatives for a regional water-supply project

Background and problem

The following is a fictional illustrative case. A growing regional city requires an additional 60,000 m³/day of reliable water. The utility proposes a new reservoir in a forested valley. The reservoir would provide drought security but inundate farmland, affect a culturally important river reach and alter downstream sediment transport. Alternatives include demand reduction and leakage control, a smaller reservoir combined with reuse, and a desalination plant supplied by renewable electricity.

Analysis

The assessment team first defined the service as reliable water supply over a 30-year planning horizon rather than “construction of a reservoir.” This allowed non-build measures to enter the alternatives analysis. Baseline work included seasonal river flow, aquatic habitat, agricultural livelihoods, cultural sites, energy demand, greenhouse-gas emissions and existing leakage.

QRA considered dam failure, construction accidents, treatment-chemical releases and drought-related supply interruption. The reservoir alternative had a very low-probability but high-consequence dam-failure scenario, requiring independent safety review, emergency planning and downstream warning systems. The reuse alternative had lower inundation but required robust treatment barriers and health-risk management. Desalination reduced river impacts but increased energy demand and brine-management concerns.

LCA showed that desalination’s operational emissions were highly sensitive to the electricity mix and plant utilisation. The smaller reservoir plus reuse option had higher treatment energy than conventional surface water but avoided much of the land inundation. CBA included capital, operation, avoided shortage losses and environmental externalities; results were tested at several discount rates and under drought and electricity-price scenarios. MCA retained non-compensable criteria: no option could receive a favourable score by monetising away violation of a protected cultural site.

Approach and solution

The preferred programme was a portfolio: aggressive leakage reduction, water-efficiency measures, a smaller reservoir outside the culturally protected reach, and staged advanced reuse. The decision included minimum ecological-flow requirements, a drought operating rule, independent dam safety assurance, benefit-sharing with affected farmers, cultural-heritage monitoring, public reporting and a five-year review trigger.

Outcome and learning points

The portfolio reduced land acquisition and ecological disruption while diversifying supply. It also required stronger institutional capacity than a single reservoir. The case demonstrates that alternatives analysis can redefine the project, that risk is not limited to pollution, that LCA exposes upstream and operational burdens, and that CBA must be complemented by rights, thresholds and distributional analysis. It also shows why adaptive management is valuable when climate, demand and technology are uncertain.

9. Governance, ethics and professional practice

Assessment quality depends on independence, competence and traceability. Consultants should disclose conflicts of interest, data limitations, model assumptions and funding influences. Public participation should be accessible, timely and responsive; consultation is not meaningful if decisions are predetermined or technical information is inaccessible. Affected people should have grievance and appeal mechanisms, and resettlement should restore or improve livelihoods rather than merely pay for land.

Environmental justice requires attention to unequal exposure and unequal decision power. The polluter-pays principle can support accountability, but inability to pay should not determine the level of protection. Intergenerational equity is especially important for climate, biodiversity and radioactive or persistent contamination. Engineers have a duty to communicate serious risks honestly and not manipulate uncertainty to justify a preferred outcome.

Regulatory requirements differ by jurisdiction, but commonly address environmental authorisation, water and air pollution, waste, occupational and public safety, protected areas, cultural heritage, land acquisition and resettlement. International lenders may impose additional environmental and social standards. Practitioners must identify the applicable legal regime rather than assume that a generic international framework is legally binding.

10. Digital technology and contemporary developments

Geographic information systems support spatial screening, habitat mapping, exposure analysis and cumulative-impact visualisation. Remote sensing can provide repeated land-cover and water-quality observations, while sensors and digital twins can support operational monitoring. Machine learning may detect patterns or accelerate scenario analysis, but it does not remove the need for causal understanding, representative data and human accountability. Biased training data can underrepresent informal settlements or marginalised groups.

Contemporary practice increasingly addresses climate resilience, nature-related dependencies, circular economy strategies, embodied carbon, biodiversity net gain, just transition and supply-chain transparency. Product environmental declarations and infrastructure carbon assessments can inform procurement, but comparability depends on consistent functional units, boundaries and verification. Climate projections should be incorporated into design life, hazard frequency, water availability and ecosystem response rather than treated as a separate appendix.

Challenges and limitations

Major limitations include incomplete baselines, uncertain future conditions, model error, weak cumulative data, inconsistent valuation, institutional fragmentation and consultation fatigue. EIA can become procedural, LCA can shift burdens between impact categories or locations, QRA can create false precision, and CBA can undervalue non-market and future interests. No tool is neutral: system boundaries, discount rates, weights, risk tolerability and significance criteria embody choices.

Best practice is to use proportional but rigorous methods, triangulate quantitative and qualitative evidence, maintain an assumptions register, conduct sensitivity analysis, use independent review for high-consequence decisions, and commit to adaptive management. The strongest assessment is not the one with the most pages; it is the one that improves the decision, protects rights and makes residual uncertainty governable.

Chapter Summary

Environmental and social assessment is a decision process that links project activities to receptors, consequences, mitigation and monitoring. EIA should begin early and compare realistic alternatives, including demand management and the no-project option. Baselines must describe trends and future-without-project conditions. Cumulative assessment considers interactions among multiple activities, while SEA addresses policies and plans.

Quantitative risk assessment combines likelihood and consequence, but expected values and probability models depend on clear scenarios and assumptions. LCA evaluates environmental burdens across a defined life cycle using a functional unit, system boundary, inventory and impact-assessment method. CBA discounts future monetised benefits and costs, yet requires sensitivity, distributional analysis and safeguards for non-market values. MCA can structure trade-offs but must not compensate away legal rights or critical thresholds.

Effective professional practice integrates these tools with public participation, environmental justice, transparent uncertainty, enforceable mitigation, monitoring, audit and adaptive management. Digital technologies improve evidence and surveillance but do not replace judgement, accountability or ethical governance.

Key Terms

Environmental impact assessment: Systematic process for predicting and managing effects of a proposed action.

Social impact assessment: Analysis of effects on people, livelihoods, culture, health and institutions.

Strategic environmental assessment: Assessment of policies, plans and programmes before projects are selected.

Cumulative impact: Combined effect of a proposal with other past, present or foreseeable activities.

Baseline: Description of existing conditions and trends used for comparison.

Counterfactual: Expected future condition in the absence of the proposal.

Receptor: Environmental, social or cultural component that may be affected.

Impact pathway: Link from activity or source through exposure to consequence.

Mitigation hierarchy: Sequence of avoidance, minimisation, restoration and offsets.

Residual impact: Impact remaining after mitigation.

Quantitative risk assessment: Numerical estimation of likelihood and consequence of hazards.

Expected annual loss: Probability-weighted consequence across defined scenarios.

Life-cycle assessment: Evaluation of inputs, outputs and potential impacts over a system’s life cycle.

Functional unit: Quantified service used as the basis for comparison in LCA.

System boundary: Definition of processes included in an LCA.

Life-cycle inventory: Compilation of material, energy and emission flows.

Life-cycle impact assessment: Conversion of inventory flows into impact indicators.

Cost–benefit analysis: Comparison of monetised benefits and costs over time.

Net present value: Discounted benefits minus discounted costs over an analysis period.

Adaptive management: Management that uses monitoring and predefined triggers to revise action.

Review Questions

Short Answer Questions

1. Distinguish an environmental pressure from an environmental impact.

2. Why is the future-without-project scenario important in baseline assessment?

3. State the four levels of the mitigation hierarchy.

4. What is the purpose of a functional unit in LCA?

5. Why should monitoring indicators be linked to decision thresholds?

Long Answer Questions

1. Explain the stages of EIA from screening through post-approval monitoring, and discuss how public participation can influence each stage.

2. Compare project EIA, strategic environmental assessment and cumulative-impact assessment.

3. Explain QRA, including hazard, exposure, consequence, uncertainty and the interpretation of expected annual loss.

4. Describe the four phases of LCA and critically discuss system boundaries, allocation and uncertainty.

5. Discuss the strengths and limitations of CBA and MCA for infrastructure decisions involving biodiversity, cultural heritage and intergenerational effects.

Analytical / Application Questions

1. A proposed road passes near a wetland and several settlements. Develop an impact-pathway table, identify key alternatives, and propose a monitoring and mitigation plan.

2. Two water-supply alternatives have different energy, land, social and reliability effects. Design an integrated assessment using EIA, QRA, LCA and CBA, specifying which issues should not be reduced to a single monetary score.

3. A flood-defence scheme has a low-probability catastrophic failure mode and more frequent minor nuisance flooding. Explain how you would represent both risks, communicate uncertainty and establish adaptive-management triggers.

Multiple Choice Questions with Answers

Question 1

Which statement best distinguishes LCA from project EIA?

A. LCA is limited to construction-site noise, whereas EIA covers supply chains.

B. LCA evaluates life-cycle burdens using a defined functional unit, whereas EIA is generally location- and project-specific.

C. LCA is legally binding in every jurisdiction, whereas EIA is always voluntary.

D. LCA evaluates only social impacts, whereas EIA evaluates only financial costs.

Correct Answer: B. LCA evaluates life-cycle burdens using a defined functional unit, whereas EIA is generally location- and project-specific.

Question 2

What is the preferred first step in the mitigation hierarchy?

A. Offset residual impacts

B. Pay compensation

C. Avoid the impact

D. Restore the site after construction

Correct Answer: C. Avoid the impact

Question 3

If an event has an annual rate λ = 0.02 and follows a constant-rate Poisson process, its probability of occurring at least once in one year is approximately:

A. 0.02%

B. 0.20%

C. 1.98%

D. 20.00%

Correct Answer: C. 1.98%

Question 4

Which item is essential for a valid comparison in LCA?

A. Identical construction contractors

B. A common functional unit representing equivalent service

C. Exclusion of maintenance activities

D. Use of monetary values for every impact category

Correct Answer: B. A common functional unit representing equivalent service

Question 5

A positive net present value means that, at the selected discount rate:

A. Every affected group receives a benefit

B. Environmental impacts are zero

C. Discounted monetised benefits exceed discounted monetised costs

D. The project has no uncertainty

Correct Answer: C. Discounted monetised benefits exceed discounted monetised costs

Question 6

Which situation is a cumulative impact?

A. Noise from one machine considered in isolation

B. The combined reduction in river flow caused by several individually compliant abstractions

C. A laboratory measurement of one pollutant

D. A project's initial capital cost

Correct Answer: B. The combined reduction in river flow caused by several individually compliant abstractions

Question 7

Why should a significance matrix be treated cautiously?

A. It can never include stakeholder values

B. Ordinal scores may not justify arithmetic operations or imply precise probabilities

C. It cannot display qualitative information

D. It automatically excludes legal thresholds

Correct Answer: B. Ordinal scores may not justify arithmetic operations or imply precise probabilities

Question 8

In an LCA, allocation is required when:

A. A process produces multiple products and burdens must be assigned among them

B. A project has no environmental impacts

C. All data are collected from field sensors

D. The functional unit is expressed in physical units

Correct Answer: A. A process produces multiple products and burdens must be assigned among them

Question 9

Which statement about expected annual loss is correct?

A. It predicts the exact loss that will occur every year

B. It is the sum of probability-weighted consequences for defined scenarios

C. It applies only to greenhouse-gas emissions

D. It eliminates the need to identify scenarios

Correct Answer: B. It is the sum of probability-weighted consequences for defined scenarios

Question 10

What is a key ethical limitation of relying solely on cost–benefit analysis?

A. It cannot discount future values

B. It cannot use market prices

C. Monetisation may obscure rights, distributional injustice and irreplaceable values

D. It always favours environmental protection

Correct Answer: C. Monetisation may obscure rights, distributional injustice and irreplaceable values