APPENDIX 1
Field format for assessing soil contamination

Step 1
Determining the relevant pesticides

Use Table A to list all the pesticides that have been spilled at the site.

TABLE A

Now use Table B to determine which of the spilled pesticides are relevant.

TABLE B

Conclusion

Are some of the spilled pesticides to be considered relevant?   Yes/No

If yes, list the relevant pesticides in Table C and proceed with steps 2 through 6 for each pesticide considered relevant.

TABLE C

Step 2
Assessing contamination caused by infiltration

Use Tables D and E to calculate C₀ (the concentration of the pesticide in the soil at the point of the spillage).

TABLE D

TABLE E

Conclusion

C₀ pesticide = ……kg/m³

Step 3
Assessing contamination in groundwater

Use Table F to predict the transport of pesticides towards the groundwater.

TABLE F

Conclusion

Groundwater always reached. Proceed with Step 3.

Groundwater never reached. Proceed to Step 4.

Now use table G to determine C₁, the pesticide concentration in the groundwater.

TABLE G

Conclusion

C₁ pesticide = …… kg/m³

Step 4
Determining distribution by wind

Use Table H to determine whether the relevant pesticides can be distributed by wind.

TABLE H

Conclusion

Since the relevant pesticide is not available as a powder, distribution by wind will not take place.

Since the relevant pesticide is available as a powder, distribution by wind may take place.

Now use Table I to characterize the store.

TABLE I

Conclusion

The store is considered closed.

The store is considered half-open.

The store is considered open.

Now use Figure A determine whether or not emissions from the store are likely to be high.

FIGURE A
Decision tree determining the likelihood of distribution by wind

Conclusion

High emission have occurred at the site.

Intermediate emissions have occurred at the site.

Low emissions have occurred at the site.

Step 5
Identifying exposure points

GROUNDWATER

Draw up a list of vulnerable objects in the immediate surroundings of the store (within a radius of 300 metres) that might be influenced by groundwater contamination. Objects vulnerable to contamination by pesticides via groundwater are wells, springs, rivers, lakes, reservoirs and ponds.

TABLE J

Determine the principal direction of groundwater flow. In the absence of groundwater level measurements, use the direction of steepest descent of the regional topography.

Subsequently, determine the downstream quadrant by drawing two lines at an angle of 45° with the principal direction of groundwater flow, as shown in Figure B.

Check if any exposure points or vulnerable objects are located inside the downstream quadrant. Mark these objects as “at risk”.

FIGURE B
Delineation of the downstream quadrant

Conclusion

There are no relevant points exposed to groundwater contamination.

Identified exposure points are ................. at ................. metres from the store.

WIND

Use Table K to list the vulnerable objects in the immediate surroundings of the store (within a radius of 300 metres) where the topsoil might be contaminated by wind.

TABLE K

Conclusion

There are no relevant points exposed to contamination by wind.

Identified exposure points are ................. at ................. metres from the store.

Step 6
Predicting concentrations at the exposure points

POINTS EXPOSED TO GROUNDWATER CONTAMINATION

First, use Table L to calculate the relative distance (d) for each relevant pesticide.

TABLE L

If one of the exposure points is a well, spring or river, calculate the mixing ratio m_g. If other exposure points are lakes, reservoirs or ponds, calculate the mixing ratio m_s. See page 53.

pesticide: (R × A)/Q = .................

The mixing ratio m_g pesticide = .................

Now calculate a correction factor (f_g) that takes into account hydrodynamic dispersion. Use Figure C to look up the value for f_g corresponding to the relative distance d (calculated in Table L).

FIGURE C
The correction factor f_g as a function of the relative distance d

f_g pesticide = .................

Next, use Table M to calculate concentrations at the relevant exposure points (C_g).

TABLE M

Conclusion

The calculated concentration of pesticides in the well/spring/river (C_g) is C_g = C₁ × f_g × m_g = ................. kg/m³ × 1 000 000 = ................. μg/l. Notrelevant. There are no relevant points exposed to groundwater contamination.

For a lake, reservoir or pond with water volume V, calculate the mixing ratio (m_s):

pesticide: R × A/Q = .................

The mixing ratio m_g pesticide = .................

Then, calculate a correction factor (f_s) that takes into account hydrodynamic dispersion. Use Figure D to look up the value for f_s corresponding to the relative distance d (calculated in Table L).

FIGURE D
The correction factor f_s as a function of the relative distance d

f_s pesticide = .................

Next, use Table N to calculate concentrations at the relevant exposure points (C_s).

TABLE N

Conclusion

The calculated concentration of pesticides in the lake/reservoir/pond (C_s) is C_s = C_l × f_s × m_s = ................. kg/m³ × 1 000 000 = .................μg/l. Not relevant. There are no relevant points exposed to groundwater contamination.

POINTS EXPOSED TO CONTAMINATION BY WIND

In Step 4 (Figure A) the level of emissions by wind were determined (as high, intermediate or low). Now use Figure E, F or G to determine the deposition at the exposure points.

FIGURE E

High emission

FIGURE F

Intermediate emission

FIGURE G
Low emission

Conclusion

The expected deposition at the exposure points (based on Figure E,F or G) at ................. metres from the store is ................. g/m²/year. Not relevant. There are no relevant points exposed to wind contamination.

Step 7
Identifying exposure routes

Use Table O to choose the relevant exposure routes.

TABLE O

Conclusion

The relevant exposure route at the location for ................. is ................. Proceed with Step 8.

There are no relevant points exposed to groundwater contamination.

There are no relevant points exposed to wind contamination.

Step 8
Determining when permissible exposure levels have been exceeded

PERMISSIBLE EXPOSURE LEVELS FOR GROUNDWATER

Use Table P to compare the predicted concentrations found in Step 6 with the permissible concentrations.

TABLE P

Conclusion

The permissible exposure level for ....................... (full exposure route) is exceeded for ....................... (name of pesticide). Contamination poses risks to human health.

The permissible exposure level for ....................... (full exposure route) is not exceeded for ....................... (name of pesticide).

Not relevant. There are no relevant points exposed to groundwater contamination

PERMISSIBLE EXPOSURE LEVELS FOR WIND

With the help of Appendix 3, select the permissible concentrations for the relevant exposure routes. List them in Table Q.

TABLE Q

Next use Table R to determine the permissible deposition.

TABLE R

Use Table S to compare the actual deposition found in Step 6 with the permissible deposition.

TABLE S

Conclusion

The deposition ....................... metres from the store is below the permissible deposition level.

The deposition ....................... metres from the store is above the permissible deposition level. Contamination of the topsoil poses risks to human health.

Step 9
Determining follow-up measures

Use Table T to determine which situation applies.

TABLE T

Conclusion

Follow-up measures are needed.

Follow-up measures are not needed.

Field format for assessing soil contamination: Example 1

Description of a storage site with obsolete pesticides¹

A large quantity of obsolete pesticides, mainly DDT, received from a European government but never used has been stored at this site, presumably since the 1960s. Although the obsolete pesticides have been properly stored since 1996, they were poorly stored before then. The DDT was originally packed in sacks and plastic, and the store consisted of a corrugated iron roof placed over four wooden poles. There were no walls. A farmhouse is situated nearby, at a distance of around 80 metres. The total amount of DDT stored is estimated at about 25 tons in powder form.

STEP 1
DETERMINING THE RELEVANT PESTICIDES

Use Table A to list all pesticides that have been spilled at the site.

TABLE A

Second, use Table B to determine which of the spilled pesticides are relevant.

TABLE B

¹ Data in boldface type are the responses for this hypothetical store.

Conclusion

Are some of the spilled pesticides to be considered relevant? Yes/No

If yes, list the relevant pesticides in Table C and proceed with steps 2 through 6 for each pesticide considered relevant.

TABLE C

STEP 2
ASSESSING CONTAMINATION CAUSED BY INFILTRATION

Use Tables D and E to calculate C₀ (the concentration of the pesticide in the soil at the point of the spillage).

TABLE D

TABLE E

8.3>0.0033 = > C_o = S

Conclusion

C_o pesticide = 0.0033 kg/m³

STEP 3
ASSESSING CONTAMINATION IN GROUNDWATER

Use Table F to predict the transport of pesticides towards the groundwater.

TABLE F

Conclusion

Groundwater always reached. Proceed with step 3.

Groundwater never reached. Proceed with Step 4.

Now use Table G to determine C₁, the pesticide concentration in the groundwater.

TABLE G

R × √A /q × b = 3.8 > 1, then C₁ = 0.0033

Conclusion

C₁ pesticide = 0.0033 kg/m³

STEP 4
DETERMINING DISTRIBUTION BY WIND

First, use Table H to determine whether the relevant pesticides can be distributed by wind.

TABLE H

Conclusion

Since the relevant pesticide is not available as a powder, distribution by wind will not take place.

Since the relevant pesticide is available as a powder, distribution by wind may take place.

Next, use Table I to characterize the store.

TABLE I

Conclusion

The store is considered closed.

The store is considered half-open.

The store is considered open.

Now use Figure A to determine whether or not emissions from the store are likely to be high.

FIGURE A
Decision tree determining emission by wind

Conclusion

High emissions have occurred at the site.

Intermediate emissions have occurred at the site.

Low emissions have occurred at the site.

STEP 5
IDENTIFYING EXPOSURE POINTS

Groundwater

Draw up a list of vulnerable objects in the immediate surroundings of the store (within a radius of 300 metres) that might be influenced by groundwater contamination. Objects vulnerable to contamination by pesticides via groundwater are wells, springs, rivers, lakes, reservoirs and ponds.

TABLE J

Determine the principal direction of groundwater flow. In the absence of groundwater level measurements, use the direction of steepest descent of the regional topography.

Subsequently, determine the downstream quadrant by drawing two lines atr an angle of 45° with the principal direction of groundwater flow, as shown in Figure B.

Check if any exposure points or vulnerable objects are located inside the downstream quadrant. Mark these objects as “at risk”.

FIGURE B
Delineation of the downstream quadrant

Conclusion

There are no relevant points exposed to groundwater contamination.

Identified exposure points are …… at …… metres from the store.

Wind

Use Table K to list the vulnerable objects in the immediate surroundings of the store (within a radius of 300 metres) where the topsoil might be contaminated by wind.

TABLE K

Conclusion

There are no relevant points exposed to contamination by wind.

Identified exposure points are houses 80 metres from the store.

STEP 6
PREDICTING CONCENTRATIONS AT THE EXPOSURE POINTS

Points exposed to groundwater contamination

First use Table L to calculate the relative distance (d) for each relevant pesticide.

TABLE L

If one of the exposure points is a well, spring or river, calculate the mixing ratio m_g. If other exposure points are lakes, reservoirs or ponds, calculate the mixing ratio m See page 53.

pesticide: (R × A)/Q = .................

The mixing ratio m_g pesticide = .................

Now calculate a correction factor (f_g) that takes into account hydrodynamic dispersion. Use Figure C to look up the value for f_g corresponding with the relative distance d (calculated in Table L).

FIGURE C
The correction factor f_g as a function of the relative distance d

f_g pesticide = .................

Next, use Table M to calculate the concentrations at the relevant exposure points (C_g).

TABLE M

Conclusion

The calculated concentration of pesticides in the well/spring/river (C_g) is C_g = C₁ × f_g × m_g = ................. kg/m³ 1 000 000 = ................. ug/l.

Not relevant. There are no relevant points exposed to groundwater contamination.

For a lake, reservoir or pond with water volume V, calculate the mixing ratio (m_s):

pesticide: R × A/Q = .................

The mixing ratio m_g pesticide = .................

Then, calculate a correction factor (f_s) that takes into account hydrodynamic dispersion. Use Figure D to look up the value for f_s corresponding with the relative distance d (calculated in Table L).

FIGURE D
The correction factor f_s as a function of the relative distance d

f_s pesticide = .................

Next, use Table N to calculate concentrations at the relevant exposure points (C_s).

TABLE N

Conclusion

The calculated concentration of pesticides in the well/spring/river (C_s) is C_s = C₁ × f_s × m_s = ................. kg/m³ 1 000 000 = ................. ug/l.

Not relevant. There are no relevant points exposed to groundwater contamination.

Points exposed to contamination by wind

In Step 4 (Figure A) the level of emissions by wind were determined (as high, intermediate or low). Now use Figure E, F or G to determine the deposition at the exposure points.

FIGURE E
High emission

FIGURE F
Intermediate emission

FIGURE G
Low emission

Conclusion

The expected deposition at the exposure points (based on Figure E, F or G) at the distance of 80 metres from the store is 150 g/m²/year.

Not relevant. There are no relevant points exposed to wind contamination.

STEP 7
IDENTIFYING EXPOSURE ROUTES

Use Table O to choose the relevant exposure routes.

TABLE O

Conclusion

The relevant exposure route at the location for houses is direct contact. Proceed with Step 8.

There are no relevant points exposed to groundwater contamination.

There are no relevant points exposed to wind contamination.

STEP 8
DETERMINING WHEN PERMISSIBLE EXPOSURE LEVELS HAVE BEEN EXCEEDED

Permissible exposure levels for groundwater

Use Table P to compare the predicted concentrations found in Step 6 with the permissible concentrations.

TABLE P

Conclusion

The permissible exposure level for ................. (full exposure route) is exceeded for ................. (name of pesticide). Contamination poses risks to human health.

The permissible exposure level for ................. (full exposure route) is not exceeded for ................. (name of pesticide).

Not relevant. There are no relevant points exposed to groundwater contamination

Permissible exposure levels for wind

With the help of Appendix 3, select the permissible concentrations for the relevant exposure routes. List them in Table Q.

TABLE Q

Next use Table R to determine the permissible deposition.

TABLE R

Use Table S to compare the actual deposition found in Step 6 with the permissible deposition.

TABLE S

Conclusion

The deposition at 80 metres from the store is below the permissible deposition level.

The deposition ................. metres from the store is above the permissible deposition level. Contamination of the topsoil poses risks to human health.

STEP 9
DETERMINING FOLLOW-UP MEASURES

Use Table T to determine which situation applies.

TABLE T

Conclusion

Follow up measures are needed.

Follow-up measures are not needed.

Field format for assessing soil contamination: Example 2

Description of a storage site with obsolete pesticides²

A vast range of used materials such as cars, tyres, desks, typewriters, barrels and batteries are stored at the ministerial depot Dar es Salaam. Outside this depot are also “obsolete” pesticides. The current supplies are stored inside.

The building in which the pesticides are stored is made of brick. The floor is of concrete and without drains or raised edges. Liquids could flow from the floor directly into the soil. The roofing material seems intact, since there are no leaks.

The supply is stored three pallets high, placing excessive weight on many of the boxes on the bottom pallets, thus increasing the risk of collapse. This could damage the primary packing material, creating a potential risk of spillages onto other packaging and on the floor. There is no first-in-first-out system, meaning that new supplies are being stacked onto old supplies, a system that could produce obsolete supplies.

Outside the building is a three-metre-long covering made of corrugated metal sheets. Under it are obsolete supplies and usable pesticides (boxes in Clingfilm) that cannot be stored inside. Among the pesticides are tyres, batteries, etc. There is no flooring, only sand.

Some of the pesticides are covered with canvas. Under this canvas are also broken jerrycans from which liquid has spilled or evaporated, leaving a solid substance. Over time, the jerrycans have become brittle and cracked.

A possible soil contamination by pesticides could not be established. There is, however, a quantity of oil on the soil.

The depot lies in the vicinity of a residential area and a market, and there is a well 100 metres from the building.

STEP 1
DETERMINING THE RELEVANT PESTICIDES

Use Table A to list all the pesticides that have been spilled at the site.

TABLE A

¹ Data in boldface type are the responses for this hypothetical store.

Now use Table B to determine which of the spilled pesticides are relevant.

TABLE B

Conclusion

Are some of the spilled pesticides to be considered relevant?   Yes/No

If yes, list the relevant pesticides in Table C and proceed with Steps 2 through 6 for each pesticide considered relevant.

TABLE C

STEP 2
ASSESSING CONTAMINATION CAUSED BY INFILTRATION

Use Tables D and E to calculate C₀ (the concentration of the pesticide in the soil at the point of the spillage).

TABLE D

TABLE E

atrazine: 1> 0.03 => C₀ = S
dimethoate: 0.7> 0.025 => C₀ = S

Conclusion

C₀ atrazine = 0.03 kg/m³

C₀ dimethoate = 0.025 kg/m³

STEP 3
ASSESSING CONTAMINATION IN GROUNDWATER

Use Table F to predict the transport of pesticides towards the groundwater.

TABLE F

Conclusion

Groundwater reached because groundwater is <5 metres. Proceed with Step 3.

Groundwater never reached. Proceed to Step 4.

Now use Table G to determine C₁, the pesticide concentration in the groundwater.

TABLE G

atrazine: (R × √A)/(q × b) = 1.73 > 1, then C₁ = 0.03
dimethoate: (R × √A)/(q × b) = 3.00 > 1, then C₁ = 0.025

Conclusion

C₁ atrazine = 0.03 kg/m³

C₁ dimethoate = 0.025 kg/m³

STEP 4
DETERMINING DISTRIBUTION BY WIND

First, use Table H to determine whether the relevant pesticides can be distributed by wind.

TABLE H

Conclusion

Since the relevant pesticide is not available as a powder, distribution by wind will not take place.

Since the relevant pesticide is available as a powder, distribution by wind may take place.

Next, use Table I to characterize the store.

TABLE I

Conclusion

The store is considered closed.

The store is considered half-open.

The store is considered open.

Now use Figure A to determine whether or not emissions from the store are likely to be high.

FIGURE A
Decision tree determining emission by wind

Conclusion

High emissions have occurred at the site.

Intermediate emissions have occurred at the site.

Low emissions have occurred at the site.

STEP 5
IDENTIFYING EXPOSURE POINTS

Groundwater

Draw up a list of vulnerable objects in the immediate surroundings of the store (within a radius of 300 metres) that might be influenced by groundwater contamination. Objects vulnerable to contamination by pesticides via groundwater are wells, springs, rivers, lakes, reservoirs and ponds.

TABLE J

Determine the principal direction of groundwater flow. In the absence of groundwater level measurements, use the direction of steepest descent of the regional topography.

Subsequently, determine the downstream quadrant by drawing two lines at an angle of 45° with the principal direction of groundwater flow, as shown in Figure B.

Check if any exposure points or vulnerable objects are located inside the downstream quadrant. Mark these objects as “at risk”.

FIGURE B
Delineation of the downstream quadrant

Conclusion

There are no relevant points exposed to groundwater contamination.

Identified exposure point is a well 100 metres from the store.

Wind

Use Table K to list the vulnerable objects in the immediate surroundings of the store (within a radius of 300 metres) where the topsoil might be contaminated by wind.

TABLE K

Conclusion

There are no relevant points exposed to contamination by wind.

Identified exposure points are ................. at ................. metres from the store.

STEP 6
PREDICTING CONCENTRATIONS AT THE EXPOSURE POINTS

Points exposed to groundwater contamination

First, use Table L to calculate the relative distance (d) for each relevant pesticide.

TABLE L1

Atrazine

TABLE L2

Dimethoate

If one of the exposure points is a well, spring or river, calculate the mixing ratio m_g. If other exposure points are lakes, reservoirs or ponds, calculate the mixing ratio m_s. See page 53.

atrazine: R × A/Q = (2 × 10) / 2000 = 0.01 dimethoate: R × A/Q = 2 × 30 / 2000 = 0.03

The mixing ratio m_g atrazine = 0.01 The mixing ratio m_g dimethoate = 0.03

Now calculate a correction factor (f_g) that takes into account hydrodynamic dispersion. Use Figure C to look up the value for f_g corresponding with the relative distance d (calculated in Table L).

FIGURE C
The correction factor f_g as a function of the relative distance d

f_g atrazine = 0.7

f_g dimethoate = 0.6

Next, use Table M to calculate concentrations at the relevant exposure points (C_g).

TABLE M

Conclusion

The calculated concentration of atrazine in the well (C_g) is C_g = C₁ × f_g × m_g = 0.00021 kg/m³ × 1 000 000 = 210 μg/l.
The calculated concentration of dimethoate in the well (C_g) is C_g = C₁ × f_g × m_g = 0.00045 kg/m³ × 1 000 000 = 450 μg/l.

Not relevant. There are no relevant points exposed to groundwater contamination.

For a lake, reservoir or pond with water volume V, calculate the mixing ratio (m_s):

pesticide: R × A/Q = .................

The mixing ratio m_g pesticide = .................

Then calculate a correction factor (f_s) that takes into account hydrodynamic dispersion. Use Figure D to look up the value for f_s corresponding with the relative distance d (calculated in Table L).

FIGURE D
The correction factor f_s as a function of the relative distance d

f_s pesticide = .................

Next, use Table N to calculate the concentrations at the relevant exposure points (C_s).

TABLE N

Conclusion

The calculated concentration of pesticides in the lake/reservoir/pond (C_s) is C_s = C₁ × f_s × m_s = ................. kg/m³ × 1 000 000 = ................. μg/l.

Not relevant. There are no relevant points exposed to groundwater contamination.

Points exposed to contamination by wind

In Step 4 (Figure A) the level of emissions by wind were determined (as high, intermediate or low). Now use Figure E, F or G to determine the deposition at the exposure points.

FIGURE E
High emission

FIGURE F
Intermediate emission

FIGURE G
Low emission

Conclusion

The expected deposition at the exposure points (based on Figure E, F or G) ......... metres from the store is ................. g/m²/year.

Not relevant. There are no relevant points exposed to wind contamination.

STEP 7
IDENTIFYING EXPOSURE ROUTES

Use Table O to find the relevant exposure routes.

TABLE O

Conclusion

The relevant exposure route at the location for a well is drinking-water. Proceed with Step 8.

There are no relevant points exposed to groundwater contamination. There are no relevant points exposed to wind contamination.

STEP 8
DETERMINING WHEN PERMISSIBLE EXPOSURE LEVELS HAVE BEEN EXCEEDED

Permissible exposure levels for groundwater

Use Table P to compare the predicted concentrations found in Step 6 with the permissible concentrations.

TABLE P1

Atrazine

TABLE P2

Dimethoate

Exposure point	Exposure route	Predicted concentration (μg/l)	Permissible exposure level (μg/l) (see Appendix 3)	Permissible levels exceeded? (yes/no)
Well	drinking-water	450	200	Yes

Conclusion

The permissible exposure level for drinking-water is exceeded for atrazine and dimethoate. Contamination poses risks to human health.

The permissible exposure level for ................. (full exposure route) is not exceeded for ................. (name of pesticide).

Not relevant. There are no relevant points exposed to groundwater contamination

Permissible exposure levels for wind

Consult Appendix 3 to find the permissible concentrations for the relevant exposure routes. List them in Table Q.

TABLE Q

Next, use Table R to determine the permissible deposition.

TABLE R

Use Table S to compare the actual deposition found in Step 6 with the permissible deposition.

TABLE S

Conclusion

The deposition ................. metres from the store is below the permissible deposition level.

The deposition ................. metres from the store is above the permissible deposition level. Contamination of the topsoil poses risks to human health.

STEP 9
DETERMINING FOLLOW-UP MEASURES

Use Table T to determine which situation applies.

TABLE T

Conclusion

Follow-up measures are needed.

Follow-up measures are not needed.