Approve agreement with Darell G. Slotton in the amount of $600,000 for the period of July 1, 2022, through June 30, 2025, for mercury monitoring services in the off-channel aggregate wet pits regulated by the Cache Creek Area Plan. (No general fund impact) (Lindbo/Sabatini)

Approve agreement with Darell G. Slotton in the amount of $600,000 for the period of July 1, 2022, through June 30, 2025, for mercury monitoring services in the off-channel aggregate wet pits regulated by the Cache Creek Area Plan.

Section 10-5.517 (Mercury Bioaccumulation in Fish) of the County’s Surface Mining Reclamation Ordinance specifies that off-channel aggregate wet pits approved for eventual reclamation to permanent pond, lake, or water feature be evaluated for conditions that could result in significant methylmercury production. The mercury monitoring program requires sampling of mercury concentrations of fish found in the wet pits; measurements of chemical and physical parameters of each wet pit through "water column profiling," and an analysis of the bottom sediments in each wet pit to identify and assess potential factors that may be causing any elevated methylmercury concentrations; and an establishment of the "baseline" fish mercury level in Cache Creek every 10 years.  Since it's inception, the County’s mercury monitoring program has been conducted by Dr. Darell G. Slotton and his research team from the University of California, Davis through contracts with the County.

The agreement subject to this staff report covers the annual fish mercury monitoring (Task 1) for 2022 through 2024, and any water column profiling (Task 2) and bottom sediment (Task 3) sampling that may be required during the contract term (through June 30, 2025). Additionally, the agreement includes establishing a new 10-year "baseline" fish mercury level in Cache Creek (Task 4). Lastly, the agreement includes two tasks for as-needed assistance with developing pit lake mercury control options (Task 5) and any as-needed support services with implementing the Off-Channel Mining Program (Task 6).

It should be noted that the agreement's not-to-exceed amount was calculated by estimating the number of pits that may be subject to the various sampling events. There are a variety of factors that go into determining which pits are sampled each year and which of the sampling events occur.  The not-to-exceed amount is a conservative estimate for three years' worth of sampling costs. The bulk of the estimated costs is associated with Task 1 (approximately $350,000). For Task 1, the County's mercury protocols call for target sample numbers for the size and age of the fish to be tested. Due to the varying availability of the fish present in each wet pit, these target numbers may not be fully achieved in each Task 1 sampling event.  

To ensure that the sampling conducted in each of the subject wet pits is consistent, and the results can be adequately compared between each pit and also each sampling event, it is imperative that a single entity conducts the sampling. As a result, staff proposes that the County administer the agreement with Dr. Slotton, and then seek reimbursement from the participating gravel producers for their respective shares of the sampling costs in a similar fashion as to what has been done previously with prior contracts with Dr. Slotton related to the mercury monitoring testing.

The agreement has been reviewed and approved as to form by the Office of County Counsel.

Natural Resources Division staff intend to procure this agreement via a Sole Source as Dr. Slotton is the only vendor that can provide the mercury monitoring services required by the County's Surface Mining Reclamation Ordinance. 

Dr. Slotton has directed applied research projects addressing heavy metal contamination and bioaccumulation issues in California for over 30 years, with a primary focus on mercury. He has led several mercury-related projects in the Cache Creek watershed since the 1980’s, developing a strong understanding of mercury dynamics in the Cache Creek Area Plan's programmatic area. Dr. Slotton has also conducted mercury bioaccumulation and source assessment studies in the Lake Titicaca watershed of Peru, the Ayeyarwaddy River system in Burma, and the Peruvian Amazon.

Additionally, Dr. Slotton has played an integral role in the development of the County's mercury monitoring program when the Cache Creek Area Plan was adopted in 1996.  More recently, he was involved in the updating of the mercury monitoring program during the Cache Creek Area Plan's 20-year programmatic update (2017-2019).  Throughout the program's existence, Dr. Slotton and his team have provided the County with updated research, recommendations, and scientific opinions. Lastly, Dr. Slotton has access to all of the high-level scientific equipment needed to conduct the various sampling services, as well as a local mercury analytical and research laboratory at UC Davis.