D3974-09 – Standard Test Method Technical Guide

ASTM D3974-09 (Reapproved 2023) provides standardized practices for the partial extraction of trace elements from soils, bottom sediments, suspended sediments, and waterborne materials. These practices are essential for environmental monitoring and pollution detection, focusing on extractable concentrations rather than total metal analysis.

📐 Extraction Practices Overview

These practices include two extraction methods: Practice A and Practice B. Practice A is a more vigorous and complicated extraction capable of determining multiple elements including aluminum, boron, barium, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, potassium, sodium, strontium, vanadium, and zinc. Practice B is less vigorous and less complicated, extracting aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, nickel, and zinc. Both practices involve acid digestion to dissociate elements complexed in precipitated hydroxides, carbonates, sulfides, oxides, and organic materials.

⚙️ Sample Preparation Methods

The standard specifies three sample preparation methods prior to digestion: freeze-drying, air-drying at room temperature, and accelerated air-drying at 95°C. These methods ensure consistency in sample preparation for accurate extraction results.

📊 Key Technical Specifications

Table 1 summarizes the elements extractable by each practice. The detection limit and linear concentration range depend on the analytical technique used, such as atomic absorption spectrophotometry. The sensitivity can be adjusted by varying the sample size or dilution.

❓ Frequently Asked Questions