1. Year “7” and Year “8” Studies Focusing on Mulch

2. Mulch – Buffer Materials
Early research has shown that mulches made from recycled dimensional wood can be contaminated with CCA (Townsend et al. 2003).
Follow-up study -> Year 7 – South Florida Year 8 – Rest of Florida

3. Mulch made from C&D Wood

4. Mulch Analysis Methods
Visual Inspection
Size Distribution
Sample
Ash for total Metals
SPLP Analysis

5. Not Positive for Arsenic: 8 Not Positive for Arsenic: 5
Mulch Ashing Results
Ashed Samples: 20
Colored: 14
Not Colored: 6
Positive for Arsenic: 6
Not Positive for Arsenic: 8
Positive for Arsenic: 1
Not Positive for Arsenic: 5
All 6 samples contained plywood
indicating that they contained recycled dimensional wood.

6. Concentration Range of Arsenic Samples

7. Arsenic vs. Chromium

8. Not Positive for Arsenic: 9 Not Positive for Arsenic: 10
Mulch SPLP Results
SPLP Samples: 32
Colored: 17
Not Colored: 15
Positive for Arsenic: 8
Not Positive for Arsenic: 9
Positive for Arsenic: 5
Not Positive for Arsenic: 10
All 8 samples contained plywood indicating that they contained recycled dimensional wood.

9. Concentration Range of Arsenic Samples

10. Arsenic vs. Chromium

11. Conclusion Engineered wood was found in 28% of consumer mulches
Arsenic was found in 35% consumer mulches
SPLP tested showed that arsenic leached from 37 % of consumer mulches
26% of these samples leached over 50 μg/L

12. Effect of Iron Oxides on Leaching of CCA
Mulch Leaching Study
Effect of Iron Oxides on Leaching of CCA