Notes from a meeting with Professor Jeznach on river microplastic sampling: contacts to follow up with, possible changes to the project's filtering and identification approach, and her sampling, collection, and laboratory methodology. Contact email addresses have been removed from this public copy.
Contacts
Sarah Davis
Davies
- Ask about recommended filter sizes.
Amaral
- Working on laser-based microplastic detection.
Questions / Possible Changes for Our Project
Filtering and Collection
- Consider targeting larger microplastics or potentially macroplastics.
- Investigate larger filter sizes.
- Follow up with contacts for filter recommendations.
Plastic Identification Methods
Potential approaches:
- Visual sorting.
- Density separation.
- Melting behavior.
Notes:
- Sand and glass typically sink.
- Many plastics float.
Professor Jeznach's Sampling Methodology
Sampling Schedule
- Sampled three times during the summer.
- Six sampling sites.
- Sampling continued through the end of July.
Sample Collection
- Four 200 mL samples collected at each site.
Site Selection Criteria
- Included both urban and rural locations.
- Sites were wadeable or accessible from a bridge.
- Sites had streamflow gauges.
- Included locations upstream and downstream of wastewater treatment plants.
- Chose straight sections of rivers rather than bends.
- Attempted to collect samples from the middle of the river.
Rivers Sampled
- Pawtuxet River
- Blackstone River
- Woonasquatucket River
Professor Jeznach's Collection Methods
Equipment
- Phytoplankton sampler.
- Metal sieve.
Low-Volume Sampling Method
- Collect 100 to 200 mL of water in a jar.
- Method effectively represents roughly 2,000 L of water filtered in about 5 minutes.
Professor Jeznach's Laboratory Procedures
Target Particle Size
- 300 μm to 5 mm.
Sample Processing
- Digest organic material with potassium hydroxide (KOH).
- Stain particles using Nile Red.
Common Findings
- Natural samples are predominantly fibers rather than fragments.
Plastic Verification
Hot Needle Test
- Simple identification method.
- Touch the particle with a heated needle.
- If it melts, it is likely plastic.
Reference: https://www.simcoastri.org/