From Consulting Services
Risk management serves to prioritise the risks to which a system is exposed, so that practices and policies can be put into place, such that:
- Risk is measured and monitored.
- Risk is reduced to acceptable levels.
- Reactive measures are put into place to respond to off-specification or accidental events.
- Preventive measures are adopted to control and/or reduce the level of risk.
The most direct procedure for evaluating environmental risk attendant to contaminants in recipient waters is a field study in which the aquatic ecosystem is monitored for damage, causal factors delineated, and the results extrapolated or generalised.
By way of thorough biological assessments, environmental impact analysis, toxicity evaluations and physicochemical analyses, EnviroGulf Consulting offers technically sound solutions to complex environmental issues.
EnviroGulf Consulting provides risk assessments tailored to our clients' specific area of interest following assessment techniques approved by regulatory authorities to which their reports are submitted. This procedure ensures the greatest chance of receiving a favourable review.
The following services are available:
- Contaminated site assessment of impacts on receiving waters:
- surface water quality
- aquatic sediments
- aquatic biological resources
- cumulative toxicity, bioaccumulation and biomagnification
- Analytical services:
- PAH, volatile aromatics, cyanides, phenols, BTEX, TPH, etc.
- general water quality determinands
- Preliminary risk assessment:
- background information and data review
- initial site inspection
- need for further investigation
- Risk assessment:
- hazard identification
- dose-response assessment
- exposure assessment
- risk characterisation
- uncertainty analysis
- Ecological risk assessment.
A review of background information and data coupled with an initial site inspection and perhaps limited sampling form part of a preliminary risk assessment that EnviroGulf Consulting undertakes on behalf of clients. The objective is either to terminate an investigation because no risk is shown or to confirm contamination and firm up subsequent site investigations to identify exposure pathways and target populations.
Risk is a measure of the probability that an adverse effect will occur. In the case of a chemical contaminant, it is a function of the intrinsic capacity of the contaminant to cause an adverse effect and the concentration (or dose).
Hazard identification as part of the risk assessment process defines the toxicological hazards posed by chemical contaminants. These hazards are summarised in a toxicity profile for each contaminant of concern.
Toxicity databases are accessed by computer to determine the relationships between observed doses or concentrations of contaminants and specified biological responses. The scientific literature is also critically appraised.
Exposure assessment as part of risk evaluation implies the need to estimate frequency of exposure. The assessment evaluates the nature and magnitude of potential exposures of receptor populations to contamination via various environmental media. Site-specific exposure scenarios are generated and environmental concentrations are presented.
Risk characterisation estimates the impact of these exposures on environmental and human health. The best estimate of potential risk as well as the highest plausible risk are presented. The weight of evidence approach is used to identify the most defensible value.
Sensitivity and uncertainty analyses are performed to quantify the uncertainty of risk assessments made. The techniques used include quantification of the effects of changing individual assumptions on the results and probability analyses.
Ecological risk assessment methodology is based on ecotoxicological approach consisting of the following components:
- Statistical analysis of contaminant concentrations.
- Probabilistic risk assessment.
Time-varying contaminant concentrations are statistically analysed and their frequency and duration in receiving waters determined. Risk is then assessed by multiplying the probability of an event by the event's consequential effects. Due to the nature of toxicological tests (LC50s, etc.), the consequential effects are presently limited to the direct effects of dissolved contaminant species.
This simplified approach allows comparison of various contaminants and determines whether concentrations exceed known toxic thresholds. EnviroGulf Consulting recognises the limitations of toxicity test data and therefore evaluates the results in light of such factors as the presence of other water quality parameters, life phase, food web, bioconcentration, bioaccumulation and biomagnification.