Contaminated Soil Monitoring

Pornsri Suthanaruk, Ph.D

Pollution Control Department (PCD)Ministry of Natural Resources and Environment

Thailand

Workshop on Strengthening Contaminated Soil Monitoring in Vietnam, 29-30 November 2011

1. Introduction

2. Assessment• Preliminary Assessment - Land use history - Soil sampling - Health and safety requirement - Soil quality standard • Detailed Assessment - Determination of Field Sample Size

3. Soil monitoring Study case:

4. Management of contaminated areas

Common sources of soil contamination

• Illegal Dumping of chemicals • Chemicals accidental site• Industrial facility or chemicals warehouse• Gas Station• Mine• Agriculture• Landfill site• New landfill site that filled by contaminated soil• Areas nearby chemicals contaminated site

Soil Quality StandardSource : Notification of National Environmental Board No. 25, B.E. (2004) issued under the Enhancement and Conservation of National Environmental Quality Act B.E.2535 (1992) published in the Royal Government Gazette No. 121 Special Part 119 D dated October 20, B.E.2547(2004)

Objectives: Protected human health

Application: - Preliminary assessment - Health and ecological risk assessments are needed if contaminants are either directly or indirectly impact to people in and surrounding the contaminated areas.Information: - Standard vales /analytical technics/ soil collecting and sample preservation technics

Soil Quality Standards

Parameter

Standard value (not exceed)Habitat and Agriculture

(mg/kg)

Other Purposes(mg/kg)

1. Volatile Organic Compounds 1) Benzene 6.5 15

2) Carbon Tetrachloride 2.5 5.33) 1,2-Dichloroethane 3.5 7.64) 1,1-Dichloroethylene 0.5 1.25) cis-1,2-Dichloroethylene 43 1506) trans-1,2-Dichloroethylene 63 2107) Dichloromethane 89 2108) Ethylbenzene 230 2309) Styrene 1,700 1,70010) Tetrachloroethylene 57 19011) Toluene 520 52012) Trichloroethylene 28 6113) 1,1,1-Trichloroethane 630 1,40014) 1,1,2-Trichloroethane 8.4 1915) Total Xylenes 210 210

Soil Quality Standards

Parameter

Standard value (not exceed)

Habitat and Agriculture

(mg/kg)

Other Purposes(mg/kg)

2. Heavy metals

1) Arsenic 3.9 27

2) Cadmium and compounds 37 810

3) Hexavalent Chromium 300 640

4) Lead 400 750

5) Manganese and compounds 1,800 32,000

6) Mercury and compounds 23 610

7) Nickel, soluble salts 1,600 41,000

8) Selenium 390 10,000

Soil Quality Standards

Parameter

Standard value (not exceed)Habitat and Agriculture

(mg/kg)

Other Purposes(mg/kg)

3.Pesticides and herbicides1) Atrazine 22 1102) Chlordane 16 1103) 2,4-D 690 12,0004) DDT 17 1205) Dieldrin 0.3 1.56) Heptachlor 1.1 5.57) Heptachlor Epoxide 0.5 2.78) Lindane 4.4 299) Pentachlorophenol 30 110

4. Others 1) Benzo (a) pyrene 0.6 2.92) Cyanide and compounds 11 353) PCBs 2.2 104) Vinyl Chloride 1.5 8.3

Soil Sampling Methodology

Source : Notification of National Environmental Board No. 25, B.E. (2004) issued under the Enhancement and Conservation of National Environmental Quality Act B.E.2535 (1992) published in the Royal Government Gazette No. 121 Special Part 119 D dated October 20, B.E.2547(2004)

1. Dividing the area into small plots. The small size of the plot depends on the size of area and landscape, aiming to obtain a representative sample of the total area.

2. Numbers of the drilling hole, depending on the size of the area. For example, the area of 10-25 rais requiring 10-20 holes spread across the plot.

3. To drill a hole, a depth of approximately 12-18 inches (30-45 cm) is suitable to undisturbed the soil sample. Reference samples have to be collected.

Soil Sample Preservation

Parameter Container Preservative Holding Time

1.) Volatile Organic Compounds Glass 4° ±2 °C 14 Days

2) Heavy metals (Except Hexavalent Chromium and Mercury and compounds)

Plastic/Glass " 180 Days

3) Hexavalent Chromium" "

- 30 Days before sample preparation - 4 Days after sample preparation

4) Mercury and compounds " " 28 Days

5) PesticidesGlass "

- 14 Days before sample preparation - 40 Days after sample preparation

6) Benzo (a) pyrene" "

- 14 Days before sample preparation - 40 Days after sample preparation

7) Cyanide and compounds Plastic/Glass " 14 Days before sample preparation

8) PCBsGlass "

- 14 Days before sample preparation - 40 Days after sample preparation

9) Vinyl Chloride " " 14 Days

Source : Notification of National Environmental Board No. 25, B.E. (2004) issued under the Enhancement and Conservation of National Environmental Quality Act B.E.2535 (1992) published in the Royal Government Gazette No. 121 Special Part 119 D dated October 20, B.E.2547(2004)

1. Introduction

2. Assessment• Preliminary Assessment - Land use history - Soil sampling - Health and safety requirement • Detailed Assessment - Determination of Field Sample Size

3. Soil monitoring Study case:

4. Management of contaminated areas

Identify contaminated areaschemical accidents, illegal dumping of chemical wastes

(industrial facilities, location of waste disposal or mining)

Identify contaminated areaschemical accidents, illegal dumping of chemical wastes

(industrial facilities, location of waste disposal or mining)

Step 1: Preliminary assessment - Search of land used area and preliminary survey - compared to the environmental quality standards

Step 1: Preliminary assessment - Search of land used area and preliminary survey - compared to the environmental quality standards

Step 2 : Detailed assessment - Check for contaminants, exposure route and vulnerable populations - Assess the health risk

Step 2 : Detailed assessment - Check for contaminants, exposure route and vulnerable populations - Assess the health risk

Step 3 : Contaminated land management planningManagement of risks to health / to ecosystem - Treatment or detention of contaminants - Restricting the use of the area.

Step 3 : Contaminated land management planningManagement of risks to health / to ecosystem - Treatment or detention of contaminants - Restricting the use of the area.

Step 4 - Monitor the effectiveness of rehabilitation - Plan for implementation safety for workers in the contaminated areas - Continuous monitoring

Step 4 - Monitor the effectiveness of rehabilitation - Plan for implementation safety for workers in the contaminated areas - Continuous monitoring

DeclineAcceptable

No action taken

No action taken

Step 1 Preliminary Assessment

Preliminary Assessment of Contaminated site

Assessment processes

1. Find the land use history

2. Survey and interview local people

3. Soil, surface water and ground water sampling

4. Sampling handling and samples analysis

If the concentrations are higher than the standard values, go to….

Step 2 : Detailed assessment

Land Use history

Source of Information: 2008 Emergency Response Guidebook

Source : NIOSH (National Institute for Occupational Safety and Health)

Tool Kit for Hazardous waste measurement

pH paperRadioactive Meter

Toxic gas and VOC meters

O2 meter

Soil sampling

Step 1 : Preliminary AssessmentThe purpose of collecting soil samples is to identify the contamination.

If the contaminants exceed the environmental quality standards, we go the step 2 which is health risk and ecological risk assessments.

Soil Sampling

Soil sampling points will be selected by using information gathered from the land used history, survey and interview with local people in order to find the type of chemicals used, collected and/or disposed in the area.

Soil sampling should be conducted in the following cases.• The area adjacent to areas where the activities which may

cause contamination. This includes areas of the landfill and chemical storage tanks located or the location where its topography is lower that the contaminated area.

• Reference or background samples will be collected to compare the data with the contaminated sites.

It should be recorded the numbers and location of sampling point on the map.

Samples were collected at three depth form the serface as follows:

How to collect soil samples

• From the surface to 0.10 meter-depth• 0.4 to 0.5 meters• 0.9 to 1.0 meters

If soil is heterogeneous mixed, the samples will be collected from each layer/ soil type. If land was contaminated vertically, samples will be collected every 0.5 meters depth from the surface or collected to above the groundwater level.

1-2 inch

30 cm.

Surface soil sampling

Field record Form

Core sampling

Cleaning sampling equipments

Step 2 Detailed assessment

Detailed assessment

• Identify the scope and level of contamination

• Identify the source of contamination

• Assess the distribution of contaminant into soil and groundwater

• Identifying the impact and risk of external areas, environmental and public health

• Contaminated sites management plan

Determination of Field Sample Size

• Grid sampling were used to determine the scope and level of contamination by soil sampling at the same distance vertically and horizontally.

• Soil samples were collected every horizontal distance of 15 meters and at a depth of 5 meters. This should be cover the area of hazardous substances contamination and the areas of potential contamination.

• Grid site may be large or small depend upon the purpose of the assessment. In the case of a large area, grid size may be lager than that of the small contaminant area.

To calculate the number of sampling points

N = kA / awhen N = number of sampling points A = area of contamination (m2) a = area hotspot (m2) k = hotspot shape constant (Vary the shape of the contaminated area)

D = (A/N) ½when D = size of square (m) A = area (m2) N = number of sampling points

To calculate the size of the grid

Predicted hotspot shape

Hotspot shape constant

(k)

Circle 1.08

Oval 1.25

unpredictable 1.50

ExampleThe contaminated area is 20,000 square meters and the size of the hotspot is 500 square meters. Assuming that the hotspot shape is a circle. (k = 1.08)

1. To calculate the number of sampling points N = kA / a N = (1.08 x 20,000) / 500 = 43.2. A number of sampling points is 44

2. To calculate the size of the grid D = (A / N) ½ D = (20,000 / 44) ½ = 21.3 The grid size is 21 x 21 square meters.

1. Introduction

2. Assessment• Preliminary Assessment - Land use history - Soil sampling - Health and safety requirement • Detailed Assessment - Determination of Field Sample Size

3. Soil monitoring Study case:

4. Management of contaminated areas

1. Introduction

2. Assessment• Preliminary Assessment - Land use history - Soil sampling - Health and safety requirement - Soil quality standard • Detailed Assessment - Determination of Field Sample Size

3. Soil monitoring Study case:

4. Management of contaminated areas

Management of contaminated areas

Management of contaminated areasContaminated sites management plan must be possible, achieve the purpose, acceptable to society, not harmful to the environment and crate risks to human health and ecosystems from contaminants in the area, all of which can be managed by controlling the factors that cause is described below.

Chemicals : The main objective is to eliminate chemical contamination. However, some chemicals can not be cleaned up, such as heavy metals, etc.

Chemicals exposure pathway : The path that chemicals can enter the human body. The routes, through which chemicals enter the body , can be controlled by prevention.

Vulnerable populations : People, plants or animals may be affected by contamination. So, preventing the entry of contaminated sites is a best alterntive to avoid health risks.

Health risk assessmentNon-cancer

HQ (Hazard quotient) = Intake / RfD

Cancer

Risk = CSF x IntakeStandard Risk < 10-5

Standard HQ < 1

Intake = C x CR x EF x EDBW x AT

when C = concentration CR = contact rate EF = exposure frequency ED = exposure duration BW = body weight AT = averaging time

Recommendations to new technical

guidelines and contaminated soil

monitoring

Your Guideline Thailand Std.(Health Risk)

• 5 HMs• 39 pesticides

• 8 HMs• 9 pesticides • 15 VOCs• 4 Others

Comparing Information

Contaminants

Beneficial UseYour Guideline (Draft) Thailand Std.• Agricultural• Forestry • residential and recreational• commercial and service• Industrial

• Residential and agricultural• Others

Technical Survey

Your Guideline (Draft)

Thailand Std.

3 steps• Basic• Condition• Detailed

2 steps• Preliminary survey• Detailed assessment

Thank you for

Your Attention