MONITORING OF LEAD IN SOIL SAMPLES SELECTED FROM AGRICULTURAL FIELD AROUND LAHORE ZUHHA TAQDEES 2512
Jul 06, 2015
MONITORING OF LEAD IN SOIL SAMPLES SELECTED FROM AGRICULTURAL FIELD AROUND LAHORE
ZUHHA TAQDEES
2512
THINGS TO BE DISCUSSED
Soil monitoring and its importance.
How to do sampling in agricultural land.
Sources concentration and health effects of
lead.
Sample preparation from field.
Methods for detection of lead in soil.
SOIL MONITORING?
IMPORTANCE OF SOIL MONITORING
Key for sustainable crop production.
Tells soil nutrient level.
Helps maintaining nutrient levels.
Every 3 years.
Harm: results older than 3 years.
WHAT IS A GOOD SAMPLE?
Same time of year
When fields are dry enough to plough
Throughout the field
Right depth
Mixed in plastic container
No leaves rocks or other things
Properly labeled
SAMPLING IN AGRICULTURE
Unique environments; managed soil.
Plowing, fertilizers, irrigation water.
1 sample/4 hectares
Top 30 cm of soil profile
Random sampling
Grid sampling
SOURCES OF LEAD
Flaking lead paint on exterior
structures
Factory pollution, incinerators,
mining
Tetraethyl lead in gasoline
Lead arsenate insecticide
Naturally occurring lead in soil
Lead in plumbing
LEAD CONCENTRATIONS IN SOIL
Natural levels: 15-40 ppm
Contaminated soils: 100 ppm
Adjacent to lead-based paints:
<10,000 ppm
1000 ppm lead is hazardous
HEALTH EFFECTS ON CHILDREN
Damage to brain & nervous system
Behavior & learning problems, hyperactivity
Slowed growth
Hearing problems
Headaches
HEALTH EFFECTS ON ADULTS
Reproductive problems
High blood pressure & hypertension
Nerve disorders
Memory & concentration problems
Muscle & joint pain
Violent Actions
SAMPLING TOOLS
Bulk samplers
Augers
Tubes
SAMPLE PREPARATION FROM FIELD
DRYING Saturated soil: Oven drying
Air drying preferable (4 to 8 days)
STORING Zip lock type plastic bag
Cool dry place
SAMPLE PREPARATION FROM FIELD
LABELLING
Unique ID number
Identify ID
PROBLEMS
Contamination by tools
crushing of stones, chalk etc.
TRANSPORTATION
For chemical analysis
PROBLEMS IN SAMPLING
Limited no. of samples
Limited amount to samples
Limited accessibility of location
METHODS FOR LEAD DETECTION
Lead Soil Test Kit
Portable XRF Technology
Spike Recovery Test Method
LEAD SOIL TEST KIT
Convenient, easy onsite procedure
Ten minute test for lead soil
Uses reagents
Affordable
Small sample is required (0.14 gram)
LEAD SOIL TEST KIT3 steps
Soil in test tube
Add reagent (30s)
Dip test strip
Color change
PORTABLE XRF TECHNOLOGY
ADVANTAGES OF PORTABLE XRF
TECHNOLOGY
• Both for site and laboratory
• No waste
• Reduction in cost and time
WORKING OF PORTABLE XRF
TECHNOLOGY
• Placed directly on soil
• Metal content over 1cm square
• Depth 2 mm
• Lead content in ppm
• In situ and ex situ
• Ex situ better
SPIKED RECOVERY TEST METHOD
%Recovery=100(Cs-Cu)
K
Where:
Cs = concentration found testing spiked sample
Cu = concentration found testing un-spiked sample
K = concentration of spike added to sample