Watershed group makes cloud seeding recommendations

M. Kate West
Chester Editor


The Almanor Basin Watershed Advisory Committee (ABWAC) met Tuesday, Nov. 15, and devoted the bulk of the meeting to the ongoing topic of cloud seeding in the Lake Almanor Basin.

The issue first surfaced when resident Lisa Marcus, at the urging of ABWAC member, David Durkin, attended the March 9 advisory committee meeting. During the public comment period she read a summary of her concerns that included questions she wanted answered by the Pacific, Gas & Electric Co.

As a first action step, ABWAC hosted a public forum in Chester May 25 that fielded a panel of seven scientists in response to stated community concerns.

Following the forum, ABWAC created a subcommittee to continue research efforts and Dick Daniel was selected to chair the effort.

Subcommittee members are Dr. Charley Plopper, Ryan Burnett, Nancy Ryan, Carl Felts and Emily Creely. Member Aaron Seandel also attended several meetings.

Daniel said the group met throughout the summer and fall to address the questions and concerns of the community.

“The members were given a number of assignments and conducted themselves very professionally,” Daniel said.

The end product of the work was a prepared paper in which the subcommittee made a number of recommendations to go forward to the Plumas County Board of Supervisors (BOS).

In accordance with ABWAC procedure, Daniel presented the recommendations to his peers Nov. 15.      He said the group work involved the studying of toxicity, public health, the fate and transport of chemicals used, the monitoring and research tied to cloud seeding and the quality control associated with the chemicals used.

He said the findings reported were broken down into related categories.

The first listed how often Pacific, Gas & Electric operates cloud seeding stations in the Lake Almanor Basin. It was reported that seeding occurs November through May of each year and, in the past 10 years, days of seeding ranged from a low of 16 days in 2010-11 and a high of 49 days in 2004-5.

The second and third categories in this section addressed the chemicals used in the operation and the subsequent presence of nano particles released by the cloud seeding generators.

The subcommittee published finding on these topics read, “It is well-recognized that chemicals in nano particle form require additional detailed information to clearly understand the hazards they pose to the environment and public health. Such detailed information is not currently available. Additionally, a lack of direct information exists on the hazards of silver iodide alone, or the hazards when silver iodide is in a complex mixture with other chemicals, especially in nano particle form.”

In the area of chemical fate and transport their studies found “Several multi-year studies, summarized in Cardno ENTRIX 2011, are unanimous in their conclusion that silver iodide used in cloud seeding is practically insoluble, does not tend to dissociate to its component ions of silver and iodine, and is not bioavailable in the aquatic environment but instead remains in soils and sediment.”

The study of toxicity produced several finds to include: “For toxic chemicals studied in any detail, including elemental and ionic silver, concentrations necessary to become toxic are much lower when in nano particle form”; “However, the potential hazards of silver iodide by itself, much less when it is mixed with other chemicals or in nano particle form, have not been studied”; and “Risks to human health are unknown for silver iodide in nano particle form.”

The findings in response to public health concerns contained two statements: “Plumas County’s age adjusted death rates for several health status indicators (specifically all cancers, lung cancers and chronic respiratory disease) fall below both the nation and state” and “There is no data currently collected that will allow a more local understanding of health trends in the cloud seeding area related to respiratory illnesses or cancers. In conclusion, there is a current lack of specific public health data to reach a scientific conclusion on whether or not residents within the cloud seeding area are experiencing any health effects as a result of cloud seeding.

The two remaining categories of the report addressed monitoring data collected that is pertinent to cloud seeding in the Almanor Basin and regulatory oversight.

Findings in the area of monitoring of silver contamination revealed a more detailed analysis of water, sediment and fish samples needs to be completed over an entire winter season.

In the final category of oversight, the subcommittee noted the responsible agency, the California Department of Water and Resources, does not include in cloud seeding a permitting and monitoring system.

In response, the finding read, “This lack of environmental review required for cloud seeding creates skepticism among the population, limits pubic awareness of the issue, and could result in delays in mitigating any significant impacts of programs.”

After Daniel’s briefing, ABWAC members weighed in on the full document and made a number of suggestions for change.

The draft contained seven recommendations.

After discussion the group reached consensus on a revised draft that will include two recommendations to the BOS.

The first recommendation may ask, when revised, for the BOS to open dialogue with PG&E about:

- Informing the county of any proposed changes to current cloud seeding programs in Plumas County, including changes in procedures, chemicals used or the frequency or duration of cloud seeding.

- Working with science staff and outside experts in the fields of ecotoxicology and atmospheric chemistry to develop a rigorous monitoring program focused on the monitoring of silver in Lake Almanor shortly after cloud seeding events throughout the winter for at least three years. Sampling should include fish, aquatic organisms and lake sediments.

- The analysis including methods that will determine whether the silver is in nano particle form and, if possible, the chemical nature of the compounds from which the silver is measured.

- Lastly, that PGE make available water quality monitoring results available to the public annually through pubic forums, presentations to ABWAC, the BOS or local newspaper.

The second recommendation asks the BOS to initiate dialogue with appropriate state representatives about regulating cloud seeding in California.

Selected members of ABWAC will present the final recommendations to the BOS during a December meeting.


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