The San Francisco Bay Branch is pleased to present:
"Geology and Geochemistry of Chromium Sources in California's Groundwater"
William E. Motzer, PhD, PG, CHG,
Senior Geochemist, TODD Groundwater
Wednesday, March 15th
Chromium (Cr) including Cr(VI) species occur in California’s groundwater from both anthropogenic and geogenic (natural sources). Past investigations largely focused on anthropogenic sources (e.g., added to water as a biocide) popularized by the 2000 movie Erin Brokovitch. More recently, groundwater investigations have considered geogenic sources with California having a unique geologic framework, including numerous areas of ultrabasic and serpentinized ultrabasic rocks. These contain abundant Cr and Cr minerals, which when weathered, can undergo transformation in the critical zone to Cr(VI) complex oxyanions.
Groundwater in alluvial aquifers derived from ultrabasic and serpentinized terrain can contain Cr(VI) oxyanions, particularly chromate (CrO42–) and dichromate (Cr2O72–), generally forming under alkaline pH and oxidizing (+Eh) conditions. In other areas, Cr(VI) oxyanions can sorb to hydrous ferrous oxide (HFO) coatings on quartz grains. For projects in which recycled water (RW) is introduced to replenish depleted groundwater supplies, changes in pH and Eh have the potential for liberating Cr(VI), arsenic, and lead. Leaching tests with stabilized RW and geochemical modeling, using USGS PHREEQC and PHAST models can be used to assess possible impacts to groundwater by these constituents.
William E. (Bill) Motzer is a registered California Professional Geologist (PG) and Certified Hydrogeologist (CHG), with PG registrations in five other states. Bill has extensive experience in conducting surface and subsurface water quality chemistry and environmental forensic investigations. Bill is a recognized expert in water quality and forensic geochemistry, with particular expertise in stable and other isotopic “fingerprinting” and age dating techniques, water quality/contaminants, and emerging contaminant geochemistry. He has conducted numerous environmental projects, throughout California and other western states. He is a past President of the San Francisco Bay Branch of the Groundwater Resources Association of California (GRA), past Vice President for the International Society of Geochemistry and Health, and contributing editor to the California Section of the American Chemical Society’s (ACS) newsletter – the Vortex (www.calacs.org).
SCHEDULE OF EVENTS:
5:30 - 6:30 p.m. - No-Host Social and Registration
6:30 - 7:30 p.m. - Dinner and Announcements
7:45 - 8:30 p.m. - Speakers
8:30 - 8:45 p.m. - Questions and Answers
Fish – Baked fresh Atlantic salmon with herb butter, served with rice pilaf and fresh seasonal vegetables
Meat – Rosemary chicken, garlic mash potatoes and fresh vegetables
Vegetarian – Portobello mushroom ravioli with an Alfredo pesto sauce
$45 for Members
$50 for Non-Members
$10 for Student attendees
THIS MONTH'S SPONSOR:
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For additional information contact:
Sr. Account Executive
1220 Quarry Lane
Pleasanton, CA 94566
ANNOUNCING SCHOLASTIC SPONSORSHIP OPPORTUNITIES - ALL PROCEEDS TO BENEFIT SCIENCE STUDENTS:
GRA San Francisco Bay Branch is interested in supporting university science students. Our Scholastic Sponsorship Program is an opportunity to publicize your business while contributing toward a good cause. Your sponsorship will be acknowledged in the announcement, at the meeting, and space will be provided for a small display and brochures. Please contact Abigail Madrone at email@example.com or at 530-756-5905 for details.
If you have any announcements or questions, please contact the Branch President, Eric Sandberg (firstname.lastname@example.org) at 415-786-7244, or Branch Treasurer David W. Abbott (email@example.com) at 510-928-4543.
We are actively looking for potential speakers. If you have a topic or suggestion, please contact the Branch President, Eric Sandberg (firstname.lastname@example.org) at 415-786-7244