Tests of plants at Warner Park have shown that some of the plants contained undesirable elements used in fireworks.

Plants were harvested for testing before and after Rhythm & Booms in 2012. Most of the plant species showed elevated concentrations of elements associated with fireworks 23 days following the event, according to a draft report.

Maximum concentrations of aluminum, barium, cobalt, iron, magnesium, sulfur, and some of the perchlorate values were either at critical levels or nearing toxicity levels for plants, according to the draft report by James P. Bennett, a member of the city of Madison's Committee on the Environment who recently retired from UW-Madison Institute of Environmental Studies.

"Based on this report, I propose that the fireworks used in the park be either low or no perchlorate. Perchlorate may have adverse health effects because ingestion can interfere with iodide uptake into the thyroid gland in mammals and aquatic vertebrates such as fish. Another option would be not to explode fireworks in a wetland area, as has been done at Warner Park for 20 years," stated Ald. Weier.

City hydrogeologist Brynn Bemis said in another draft report that included results of soil and water tests that there was a spike in perchlorate in lagoon surface water after R&B. She recommended that all fireworks debris be cleaned up to avoid leaching or contaminants and that fireworks with little or no perchlorate might be best. Perchlorate is also regarded as a potential threat to drinking water.

"Plant uptake provides a point of entry into the food chain for herbivorous animals," according to the US EPA's perchlorate toxicology fact webpage.

This is especially worrisome because residents of the Brentwood area near Warner Park have proposed a community garden in the park.

The city's Committee on Environment will consider the reports in March, but plans for Rhythm & Booms or an alternative smaller neighborhood celebration may be set by then. The tests were financed by the city of Madison and Wild Warner, a nonprofit that strives to protect the park.