1.3.1 Health, safety and environmental (HSE) monitoring

Negative effects on human health, plant or animal life are at riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event, if concentrations of hazardous substances (see 1.3.4) exceed critical concentrations. Thus, detection and monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions of concentrations in or surrounding protected subjects (see 1.1.2) is the main task of hseHealth, safety and environment monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions.

The impact magnitude of an incident is primarily related to the leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column rate, but subject to further factors:

flux density ⇒ concentration and concentration, vulnerability and value of subject Þ impact

Concentrations resulting from a leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column flux (mass flux per time) depend on the volume of the affected subject and on the intensity of mixing within this volume. Hazardous concentrations may accumulate, if mixing, dispersion or turbulence are low, if chemical reaction rates are fast or if sufficient time for accumulation is available, e.g.

1. CO2Carbon dioxide pipeline failure on a calm day in a lowland valley:
   large flux
   large affected volume ⇒ high concentrations ⇒ potential of high impact on life close little mixing to the ground

2. CO2Carbon dioxide flux into a non-ventilated, rarely used cellar:

   small flux rate
   small volume ⇒ high concentrations ⇒ localised potentially lethal impact little mixing long accumulation time

Within one protected subject, e.g. an ecosystem, the vulnerability of various species may differ significantly. For human safety, detailed relations between concentration, duration of exposure and effects caused by CO2Carbon dioxide have been established (Tab. 1-2). Human health can be at riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event in enclosed environments (cellars, caves etc.) or topographical depressions, where CO2Carbon dioxide may accumulate because CO2Carbon dioxide is denser than air (1.98 vs. 1.2 kg m^-3, respectively) and tends to build up on ground levels.

For other species more general, critical concentration thresholds have been published (e.g. Blackshaw et al., 19881988 - JK Blackshaw, DC Fenwick, AW Beattie, DJ AllanThe behaviour of chickens, mice and rats during euthanasia with chloroform, carbon dioxide and ethersee more; Zaller and Arnone, 19991999 - J. G. Zaller, J. A. Arnone, IIIEarthworm responses to plant species' loss and elevated CO2 in calcareous grasslandsee more; Loranger et al., 20042004 - Gladys I. Loranger, Kurt S. Pregitzer, John S. KingElevated CO2 and O3t concentrations differentially affect selected groups of the fauna in temperate forest soilssee more; Asshoff, 20052005 - Roman AsshoffIn situ effects of elevated CO2 on plants and insectssee more; LeachTo desolve a substance from a solid et al., 2002; Niel and Weary, 20062007 - Lee Niel, Daniel M. WearyRats avoid exposure to carbon dioxide and argonsee more). The impact of substances depends also on the environment. For example, saline formationUnderground rock where saline water occupies the tiny spaces between the grains of rock water leaking into the sea may be less dramatic than a comparable saltwater leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column into a freshwater environment. In addition, the value of the protected good matters: An acre of trees dying in a large plantation (subject to individual property rights) may not be as valuable, as an acre of the same tree species, being unique in a wider region.

The examples demonstrate that the classification of impacts in a riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event process cannot be directly linked to flux rates calculated for leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column scenarios in subsurface numerical models. Site-specific features have to be included into the assessment.