Transcript Groundwater and soil protection

Environmental remediation
GROUNDWATER AND SOIL
PROTECTION
Hydrologic cycle
When rain falls to
the ground, the
water does not
stop moving.
Some of it flows
along the surface
in streams or
lakes, some of it
is used by plants,
some evaporates
and returns to the
atmosphere, and
some sinks into
the ground
Groundwater flow
Groundwater is water that is found
underground in cracks and spaces
in soil, sand, and rocks. The area
where water fills these spaces is
called the saturated zone. The top
of this zone is called the water
table...just remember the top of
the water is the table. The water
table may be only a foot below the
ground’s surface or it may be
hundreds of feet down.
Groundwater is stored in—and moves slowly through—layers of soil, sand, and
rocks called aquifers. The speed at which groundwater flows depends on the size
of the spaces in the soil or rock and how well the spaces are connected. Aquifers
typically consist of gravel, sand, sandstone, or fractured rock like limestone. These
materials are permeable because they have large connected spaces that allow
water to flow through.
Aquifers
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Aquifers are soil or rock
layers that are good
reservoirs that are easy to
produce
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High porosity: lots of pore
space between grains to
store water
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High permeability: good
connectivity between pore
spaces so water can easily
flow into and out of the
reservoir.
Above and below the water table
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The Water Table is the depth to the part of the
soil or rock that is saturated with water
Storage capacity (also related to specific yield)
is how much water we can drain from an
aquifer
Saturated zone: a portion of the soil profile
where all pores are filled with water. Aquifers
are located in this zone. There may be
multiple saturation zones at different soil
depths separated by layers of clay or rock.
Unsaturated zone: a portion of the soil profile
that contains both water and air; the zone
between the land surface and the water table.
The soil formations do not yield usable
amounts of freeflowing water. It is also called
zone of aeration and vadose zone
Capillary Zone – the transition between
vadose & phreatic (only a few cm thick, at
most). Water can be “wicked” from phreatic to
vadose zone. Deep phreatic zone can keep a
shallower vadose zone productive in drought
The contamination of
groundwater and soil
Legislative background
Important international legislation on groundwater
 The Water Framework Directive of EU:
maintain the balance of withdrawal and recharge and to prevent or reverse the deterioration of
the qualitative status of groundwater
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Groundwater Protection Directive (80/68/EEC): deals with the protection of
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The Nitrate Directive (911676/EEC): covers the protection of waters against pollution
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The directive 85/337/EEC on the assessment of the effects of certain
public and private projects on the environment
The directive 96/61/EC concerning integrated pollution prevention
and control
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groundwater against pollution caused by certain dangerous substances. It classifies
dangerous substances into List I and List II depending on the level of danger caused by the
relevant substances
caused by nitrates from agricultural sources.
The most important home legislation regarding the groundwater
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Act LIII of 1995 on the general rules of environmental protection
The Government Decree No. 219/2004. (VII. 21.) on the protection of groundwater
And in your country how does it works?
Remediation process
Remediation is a procedure including technical, economic and administrative
activities aimed at gaining knowledge about threatened, polluted and damaged
groundwater and geological media as well as at ceasing or reducing contamination,
damage and risk, and at the monitoring thereof
Environmental remediation
Site investigation
Technical intervention
Risk assessment
Remedial monitoring
Remained risk after the
technical intervention
The remediation target limit value
Quantitative risk assessment means a detailed assessment procedure based on the
sitespecific investigations of a given contaminated site. The result is represented by
risk ratio value, expressing the proportion of the actual level of pollution in the
environmental elements (especially in groundwater) and the levels of pollution
acceptable for the environment, ecosystem and human beings
Site investigation
In the course of site-specific investigations:
the
spatial occurrence of any such pollutant shall
be investigated that may likely to be present as a
result of activities and technologies applied on the
site;
detailed
chemical investigations shall be carried
out in both the geological medium and groundwater
to enable the detection of the occurrence of each
pollutant causing the contamination.
Report on site investigation
Presentation of the affected area
Methodology of site investigation
Findings of the investigation
Results of the risk assessment
Presentation, characterisation of possible options for technical
Results of the cost-benefit and cost-effectiveness analyses
interventions
Presentation and justification of the proposed option
Plan of monitoring for the period following the site investigation
Technical intervention
Treatment of soils, sediments and sludge
In situ technologies
Bioventing , Enhanced bioremediation , Landfarming , Natural attenuation , Phytoremediation , Electrokinetic remediation,
Fracturing , Soil flushing , Soil vapour extraction, Solidification/Stabilisation , Soil vapour extraction thermally enhanced
Ex situ technologies
Biopiles , Composting , Degradation by fungi , Agrotechnical soil treatment , Slurry phase bioremediation , Chemical
extraction , Chemical oxidation-reduction , Dehalogenation, Separation , Soil washing , Soil vapour extraction , Solar
detoxification , Solidification, stabilisation , Hot gas decontamination , Incineration , Open burning/Open detonation ,
Pyrolysis , Thermal desorption , Capping , Capping, drainage and recultivation , Excavation, transport and deposition with soil
replacing
Treatment of shallow groundwater, surface water and leachate
In situ technologies
Cometabolic degradation, Enhanced bioremediation , Natural attenuation , Phytoremediation , Soil vapour extraction , Air
sparging , Vacuum-enhanced free-product recovery and bioventing , Directional wells , Dual phase extraction , In-well air
stripping , Hot water or gas stripping , Hydrofracturing, Passive/active treatment walls
Ex situ technologies
Bioreactor , Constructed wetlands , Adsorption, absorption , Air stripping , Activated carbon adsorption , Ion exchange,
Precipitation, coagulation , Separation , UV oxidation, Groundwater pumping , Barriers
Treatment of exit gas (emission into air)
Biofiltration , High energy destruction , Membrane separation , Oxidation , Activated carbon adsorption
After the technical
intervention
Report on technical intervention
 Presentation of the completed technical intervention and remedial
technology/technologies applied
 Results of the technical intervention
 Presentation of the remediation monitoring operated in the course of
technical Intervention
 Draft proposal for remedial monitoring
The responsible authority shall make a decision upon:
 continuing the technical intervention if it is considered inefficient;
 additional investigation; or
 completion of the technical intervention and adoption of the final
report; also
 remedial monitoring; and/or
 termination of remediation.
Remedial monitoring
Determination of the installations of the monitoring systems
Scope of the monitored parameters in different environmental
elements.
Frequency of monitoring.
Methodology of the measurements, observations, detection and
sampling.
Registration of the measured, detected and observed data, and
order of data processing.
Order of data evaluation and reporting. Results of the evaluation
shall include outcomes on the following:
the condition of the monitoring installations;
sampling regularity;
sampling reliability;
the reliability of field analyses;
the reliability of laboratory analyses;
the correlation between data and the relevant limit values;
trend analyses and the identifiability of trends;
proposal for eventual modifications.
Short overview of monitoring results, specifically detailing as to what
part of the polluted area was spatially delimited by monitoring.
Effect:
Environmental risk
Exposure:
Source:
Location and content of priority
pollutants in the ground, supplied by
deposition
or
contamination
from
anthropogenic activities. The source refers to
the original placement and contents of the
contaminant, independent of distribution and
degradation.
Source
Contact
between
a
chemical
substance and a receptor
(human beings or the
ecosystem).
Exposure
In this instance, the influence
of soil contamination on human beings
and the environment. The effect can be
a measurable change in the soil or
recipient in relation to the expected
condition as a result of the influence
from the contaminated site. The effect
includes concentrations above the
natural background level and the
influence on life generally. Effects may
be negative, positive or neutral with
respect to life and health.
Receptors
Effect
Transport
Risk:
Transport (mechanism):
The different mechanisms leading to
the migration of the contaminant (for
example in the air, soil or water
phase).
Receptors:
General
description of human beings,
animals, birds, plants, fungi,
algae,
fish,
crustaceans,
shellfish and bacteria.
Risk
Risk designates the
danger that undesirable events
represent for humans, the
environment (ecosystem) or
material values. Risk is
expressed as the probability
and consequences of the
undesirable events.
Risk assessment investigation
The following parameters
must be determined:
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all relevant exposure pathways.
expected contaminant concentrations
in all the different exposure pathways
(load/dosage).
which receptors (humans, animals, fish,
shellfish, birds, plants, mushrooms,
algae, bacteria, etc.) are most likely
exposed to the contaminant and those
whose
protection
is
desired
(environmental objective).
which
tolerance
concentrations
(acceptance criteria) exist for the
relevant receptors.
the probability that the contaminant
may spread such that other receptors
or additional exposure pathways must
be considered
This
tiered
approach
for
assessments makes it possible
provide the same degree of safety
protection to humans and
environment when determining
course of action, even when
available information is limited.
risk
to
and
the
the
the
Tiered risk assessment
Tier 1: Simplified risk assessment
(use of soil quality guidelines)
Tier 2: Expanded risk assessment
(calculation of exposure)
Tier 3: Expanded risk assessment
(measurement of exposure)
Problem description
Information about the site
 Description of the source (expected contaminants)
 Migration/transport related information
 Effect related information (based on the present land use
and planned land use)
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Description of the source
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Primary sources (based on present and
earlier land use)
Contaminant (amount, environmentally
related substance information)
Secondary sources (contaminated surface
soil (< 1 m deep), mineral soil (> 1 m deep),
groundwater, free-phase, surface water,
sediment (freshwater/marine))
Possible location of primary and secondary
sources
Other relevant information (time aspects
for possible contamination and other
activities that may have influenced primary
and secondary sources)
References/uncertainty
in
available
information
Migration/transport related
information
Possible migration routes (soil, water, air)
Migration/transport related
information
Site specific data
Migration/transport related
information
Pollutant specific data regarding the transport process
Molar weight
 Analytical detection limit
 Density
 Mobility (diffusion factors in water and air)
 Solubility
 Vapor pressure
 Henry’s constant
 Sorption parameters (Kd, Kp, Koc, Kow)
 Degradability
 Viscosity
 Bioconcentration factors

Effect related information
Land use and
existing
conditions
Exposure
pathways
Receptors
Toxicitiy parameters
Ecotoxicological data:
LC50/LD50
EC50/ED50
NOEC
PNEC
Human toxicological data:
RfC
RfD
SF
UR
Exposure and effect
• ingestion of soil or dust.
• dermal contact to soil or dust.
continuous
periodic
• inhalation of dust.
• inhalation of soil vapour through indoor air
time
stochastic
• intake of drinking water from a groundwater well
time
concentrated
• consumption of vegetables and crops grown at the contaminated site.
• consumption of fish or shellfish from a nearby recipient contaminated by gw
time
• dermal contact to drinking water (by showering).
time
• inhalation during showering.
• dermal contact during outdoor bathing.
Effect
%
Extrapolated
range
Effect
%
Maximum
effect
Observed range
Extrapolation
Dose
mg/kg/day
Dose-effect curve of the
carcinogenic pollutants
No
effect
Dose
Limit dose
mg/kg/day
Dose-effect curve of the noncarcinogenic pollutants
Calculation of human risk for
non-carcinogenic materials
The exposure can be expressed with average
daily dose (ADD)
ADD= (C × ADI × fexp) / BW [mg/kg×d]
Where:
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C: the pollutant concentration in the media [mg/kg], [mg/l]
ADI: average daily intake [kg/d], [l/d]
fexp: fraction exposure time [d/d]
BW: body weight [kg]
Calculation of human risk for
non-carcinogenic materials
In case of dermal contact:
ADI = SA × AF × DA
Where:
 SA: Surface Contact Area [cm2]
 AF: Soil Adherence Factor [mg/cm2/d]
 DA: Dermal Adsorption Factor [-]
In case of inhalation we determine the Average Inhalated
Exposure Concentration:
AIEC = C × fexp
Where:
 C: the pollutant concentration in the media [mg/m3]
 fexp: fraction exposure time [d/d]
Evaluation of the calculated
risk for non carcinogenic
materials
RQ = ADD / Rfdo
Risk quotient (RQ)
Scale of the risk
<0,01
negligible
0,01-0,1
small
0,1-1
medium
1-10
high
>10
very high
RQ = AIEC / Rfc
RQ = ADD / Rfdd
Calculation of human risk for
carcinogenic materials
 As for the carcinogenic materials we are
taking into account the life-span dose:
LADD = ADD × ED/AL
LAIEC= AIEC × ED/AL
Where:
 ED: exposure duration [year]
 AL: average life [year]
Calculation of human risk for
carcinogenic materials
CR=1-exp-(SF×LADD)
Where:
SF: slope factor [1/(mg/kg×d)]
LADD: life-span average daily
dose[mg/kg×d]
Evaluation
For one substance
CR>10-5 /yr
(10 µrisk/yr) → risk
CR=1-exp-(UF×LAIEC)
Where:
UF: unit of risk [-]
LAIEC: life- span average inhalated
exposure concentration[-]
Cumulative value
CR>10-6 /yr
(1 µrisk/yr) → risk
Thank you for your
attention !
The next time:
Petroleum Hydrocarbons in groundwater and
soil and the applicable remediation
technologies thereof