Determination of lead and cadmium levels in soil-grown and hydroponically-grown lettuce

Date

4-2008

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Myrna S. Rodriguez

Abstract

The lettuce varieties (Lactuca sativa Lin): Denies Green, Green Rapids and Lollo Rosa grown in soil and nutrient solutions grown at two plant sites were analyzed the cadmium and lead contents using Flame Atomic Absorption Spectrophotometry (FAAS). Soil and nutrient solutions where the samples were grown were subjected to the same analysis.

Lead and cadmium concentrations in the soil samples fell within the normal range in soils.  The nutrient solution, on the other hand, had very low to non detectable levels in cadmium and lead.

Mean Pb concentrations in lettuce grown in soil and soilless medium ranged from 3.128 to 8.644 mg/kg dry weight.  Mean concentrations of cadmium in lettuce had values within 0.350 to 0.706 mg/kg dry weight.  Significant differences indicate Pb and Cd concentrations dependency on the variation in genetic make-up and environmental conditions.  The growth medium where the lettuce had been planted has no significant effect in the amounts of lead and cadmium in the lettuce.

values of metal levels in lettuce samples are below the maximum allowable limit set by ATSDR (1993) which are 1.00 mg/kg Cd and 4.00 mg/kg Pb, in fresh weight basis .  Based from these value an average of 2.5 and 8.1 kg of lettuce intake per week is allowed for a 50-kg individual without exceeding the PTWI set by JECFA (2000; 2005) for lead and cadmium, respectively.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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