Lead, arsenic remediation at McGregor park site could cost $110,000

Mar 8, 2017 | News

By Jondi Gumz, Santa Cruz Sentinel

The discovery of lead and arsenic in the soil during the McGregor Park construction is boosting the cost to $111,000, doubling the price tag.

The City Council, which meets at 7 p.m. Thursday at City Hall, 420 Capitola Ave., will get a report on the contamination and vote on transferring funds set aside for utility undergrounding to pay for remediation.

About $34,000 of the extra cost is to pour concrete around ramps for skateboarders instead of asphalt, so as to avoid maintenance problems.

Steve Jesberg, the city’s public works director, recommends targeted excavation of three locations with elevated contamination and bringing in clean fill material for the park at 1560 McGregor Drive.

The plan, devised by Watsonville environmental engineering firm Weber, Hayes & Associates, calls for removing 231 tons of soil from an arsenic “hot spot” and 246 tons of soil from two lead “hot spots” for disposal at the Marina landfill.

Weber Hayes recommended this option as “the most reasonable and appropriate,” saying removing lead and reducing the arsenic risk would be “protective of human health” and “relatively cost effective.”

The firm estimates the remedial work would take eight weeks.

The other options were doing nothing, which would shut down the park project until remediation was completed, or excavating the entire site, nearly 52,000 tons of soil for $3.1 million.

The city was notified of the contamination last October by the county Environmental Health Service soon after Earthworks began work at the site.

The county ordered an assessment based on soil samples indicating elevated levels of lead and arsenic, taken in 2012 when the city sold part of the property to Soquel Creek Water District for a pump station.

Before 1964, the property was part of an apple orchard. Early pesticides were heavily based on arsenic and lead, according to historian Sandy Lydon.

Tests of 51 soil samples in 2014 found elevated lead at two shallow sites and arsenic exceeding the risk limits although Weber Hayes noted most areas locally have naturally occurring arsenic exceeding those levels.

In two samples, lead levels were 120 parts per million and 220 parts per million respectively, exceeding the state’s residential limit of 80 parts per million. In samples deeper than two feet, lead concentrations were 5.8 parts per million and 18 parts per million.

For more samples, arsenic concentrations were less than 9.6 parts per million, but two were at 31 parts per million and 40 parts per million, respectively.

Weber Hayes estimated arsenic concentration for the entire site to be 7.6 parts per million, concluding arsenic remediation was not necessary.

That is based on a health risk assessment Copeland and Associates toxicologists calculated to be 14 parts per million for a youth age 5 to 18, assuming exposure of six hours a day three days a week for 50 weeks a year for 14 years.

However, the city of Capitola plans to remediate the areas with the two highest arsenic levels as a “good faith effort,” Weber Hayes’ report said, “to provide extra assurances that the underlying fill is completely safe for users of this multiuse park.”

Tests did not find significant pesticides or fuel contaminants, leading Weber Hayes to conclude the higher levels of lead and arsenic came from imported fill, such as asphalt grindings from local public works projects.

Last year, the city allocated $100,000 for a skate park at the site, and Marc Monte of the Rudolph Monte Foundation committed $50,000. Family Cycling Center and CrossFit put in $15,000 for the bike pump track and the nonprofit Ozzi Dog Park and Plantronics made donations for the $8,000 dog park.

Three other properties that required remediation, according to county environmental health director John Hodges, include 14 Walker St., Watsonville, former manufactured gas plant, where elevated levels of arsenic and other chemicals were detected; 745 Ocean St., Santa Cruz, former gas station, where elevated arsenic was detected, and 2020 N. Pacific Ave., Santa Cruz, former gas station and auto repair shop, where elevated arsenic and other chemicals were detected.

SOIL CONTAMINATION

This chart shows the highest concentration of chemicals found in soil at the McGregor Drive property in Capitola slated for a multiuse park. Two of the 51 soil samples exceeded the residential lead limit of 80 parts per million and the commercial limit of 320 parts per million. Of 89 samples tested for arsenic, 83 contained a relatively low level of arsenic; two samples were at 31 and 40 parts per million.

Chemical Range in parts per million Depth Remedial goal

Lead .6 to 520 ppb 1.5 feet 80-320 ppm

Arsenic <.5 to 40 1 foot 14 ppm

Source: Weber, Hayes & Associates