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