Miami officials found significantly higher levels of soil contamination than earlier detected in a playground at a popular Coconut Grove park and for the first time discovered at least one of the toxic chemicals has seeped into the groundwater.
A report released Tuesday by the countys environmental office concludes that solid waste dumped years ago at Blanche Park at 3045 Shipping Ave. and buried beneath a layer of artificial turf has tainted soil in the playground with heavy metals, sometimes at 40 to 50 times acceptable levels. Two monitoring wells dug as part of the testing also revealed groundwater with elevated levels of antimony, a chemical used in paints, ceramics, glass and batteries, and which can cause lung and heart disease.
Despite the findings, officials have kept the park open and do not consider it dangerous because the artificial turf over the playground acts as a protective cap.
The results have been handed over to state health officials, who will determine whether any steps need to be taken to address health concerns, said Luis Espinoza, a spokesman for county environmental chief, Wilbur Mayorga, who was not available for comment.
Of the 11 spots tested in the playground, workers found heavy metals in 10 locations and dioxins, highly toxic carcinogens, in three. In the adjacent dog park, they found a handful of samples with elevated levels of arsenic, but at far lower amounts.
Because most of the contamination is two to four feet below ground and covered with turf, todays park users dont necessarily need to worry about exposure, said Gurpal S. Toor, a University of Florida associate professor of Environmental Soil Chemistry and Water Quality.
But these heavy metals are not going to disappear magically from the site, he said in an email. If the groundwater table increases, it can potentially mobilize the metals and contaminate water. Again, this is not a direct concern for park users, but important for protecting our sensitive groundwater/aquifer.
Sampling focused on the playground area, where workers found the largest deposits of waste typical of ash. The city purchased the site in 1943 to use as a dump and an ash pit from a nearby municipal incinerator. It converted the land to a park in 1962, but did not remediate the soil, as federal mandates on treating the soil werent established until much later.
Waste was first found on the parking lot surface as well as beneath the turf and in about nine inches of soil in the playground. Almost all the heavy metals were where ash was also found, the report said. The new tests show visible signs of solid waste and elevated levels of metals throughout the playground, including arsenic, barium, copper, iron and lead. Cadmium was found below exposure limits in soil, but above rates set for possible leaching into groundwater.
And while dioxins above acceptable levels were detected in the playground in both the southwest and northeast corners they were not high enough to pose any real danger to groundwater, Toor said.
Exposure to high amounts of dioxins are known to increase risks of cancer and may cause developmental and reproductive problems, according to the National Institute of Environmental Health Sciences.
Heavy metals, particularly arsenic, can cause skin disorders and increase the risk for diabetes, high blood pressure and certain cancers. Heavy exposure would produce immediate symptoms including nausea, vomiting, dehydration and shock.