The U.S. EPA created a report called “Ecological Soil Screening Levels for Chromium” in March 2005 to quantify at what levels of chromium should prompt further investigation. The 106-page “Eco-SSL” document was revised in April 2008. On page 2, the description of the two valences gives insight into the environments they exist in:
In general, chromium (VI) is favored by higher pH, aerobic conditions, low amounts of organic matter and the presence of manganese and iron oxides which oxidize chromium (III). Transformation of chromium (VI) to the trivalent form tends to occur in acidic, anoxic soils with high organic content. Chromium (III) is cationic and adsorbs onto clay particles, organic matter, metal oxyhydroxides, and other negatively charged particles in contrast to chromium (VI) which does not interact significantly with clay or organic matter. As a result, chromium (VI) is more water-soluble and mobile than chromium (III).
Runkle Canyon soil contains low amounts of organic matter and the DTSC-tested white precipitate had extremely high levels of iron.
This same EPA report lists Eco-SSLs that show that the Runkle Canyon chromium, regardless of valence, could present a threat to plant and animal life.
Notably, the EPA Eco-SSLs indicate that trivalent chromium seems more dangerous to avian and mammal life than hexavalent chromium. The opposite is true as it relates to humans. For example, the mammalian Eco-SSL for Cr (III) is 34 mg/kg while the standard for Cr (VI) is 130 mg/kg. The Runkle Canyon white evaporate sample, if completely Cr (III), is 38.24 times over this limit while the Cr (VI) is 10 times over meaning the hexavalent chromium is a quarter as dangerous to mammals than the trivalent form.
Following is a list of species-specific Eco-SSLs for both trivalent and hexavalent chromium. The amount of related exceedances in the Runkle Canyon sample follow the numeric limits and are bolded.
P.9/106: Table 5.2 Calculation of the Avian Eco-SSLs for Trivalent Chromium
Avian herbivore (dove): 78 (16.66 times over Eco-SSL)
Avian ground insectivore (woodcock): 26 (50 times over Eco-SSL)
Avian carnivore (hawk): 780 (1.6 times over Eco-SSL)
P. 16/106: Calculation of the Mammalian Eco-SSLs for Trivalent Chromium
Mammalian herbivore (vole): 380 (3.42 times over Eco-SSL)
Mammalian ground insectivore (shrew): 34 (32.23 times over Eco-SSL)
Mammalian carnivore (weasel): 180 (7.22 times over Eco-SSL)
Calculation of the Mammalian Eco-SSLs for Hexavalent Chromium
Mammalian herbivore (vole): 1400 (92% of Eco-SSL)
Mammalian ground insectivore (shrew): 130 (10 times over co-SSL)
Mammalian carnivore (weasel): 870 (1.49 times over Eco-SSL)
Runkle Canyon is home to seven species of hawks which, according to these numbers, may be threatened by the levels of chromium in Runkle Canyon’s white evaporate. The specifically noted animals listed above that are confirmed to live in Runkle Canyon include ring-tailed weasels and doves which would also appear to be impacted at these levels, though no definitive study has been made regarding the canyon’s wildlife and chromium.
Here, there and everywhere – chromium precipitate in Dayton Canyon?
In a July 22, 2004 Los Angeles CityBeat/ValleyBeat cover story entitled “Two Mile Island,” we wrote about a development in the eastern San Fernando Valley, on the opposite side of Rocketdyne:
Another development in the works is Dayton Creek Estates, which is a mile downwind from SSFL in Los Angeles County. One hundred and fifty single-family homes are planned there on 64.2 acres out of the development’s 359.4 total acreage. Dayton Creek runs through the project and is fed by SSFL’s Happy Valley drainage, which has undergone massive excavation due to perchlorate contamination. The project’s 1999 Final Environmental Impact Report (FEIR), fully aware of SSFL’s proximity, doesn’t note impacts on the development from SSFL in its “areas of controversy” section. The Los Angeles Regional Water Quality Control Board (LARWQCB) estimates that 69 million gallons of discharges, from SSFL rocket engine tests alone, go down Dayton and an adjacent creek every year. The developers do note, however, that the FEIR is not a “definitive investigation of contamination.”
At the June 19, 2008 Santa Susana Field Laboratory (Rocketdyne) Workgroup Meeting in Simi Valley, a resident spoke during public comment about what he had found a three weeks earlier in Dayton Canyon. Dave Carey who lost a brother to cancer that he blames on Rocketdyne’s pollution, said that he saw a mysterious white evaporate, including white rocks, all along the upper reaches of the creek running through the property, some of which he had collected and had in his car outside in the parking lot. He wanted to know what this new stuff was and if DTSC would test it.
“I’m not sure how this wetness came about – there hadn’t been a rain since March or February” Carey said according to Adam Salkin who filmed the meeting and transcribed excerpts of it for EnviroReporter.com. Carey said that the rocks he found at Dayton had a “fresh salt” on them in the creek bed.
“This is Dayton Canyon – it’s a fresh salt and I’m more than willing to show you guys where this is. I had an emergency room doctor who accompanied me on this hike and saw this salt. My mother was there who saw this salt. I have it right here in my car in a box. Why isn’t the DTSC sampling this and how come other previous samples that I’ve given to your staff weren’t sampled to find out what this salt is?”
Jim Pappas, DTSC Chief of Northern California Permitting and Corrective Action Branch, sitting in on the Workgroup panel for Norm Riley, dismissed Carey’s concern yet what he said suggests what is in Runkle Canyon is in Dayton Canyon too.
“I’m familiar with your request about the salts, and we have sampled the [unintelligible] salts found on the rocks of Dayton – and the concern was…we looked for it for perchlorate and the samples for perchlorate came up “non detect,” Pappas said. “We were in Runkle canyon and observed a similar kind of salt – a crystal on the rocks there too, and um…had it analyzed and although they were different drainages obviously we checked the precipitate salt and found that it wasn’t a problem to public health.”
“I’d be more than happy to share with you the analytical results of our previous investigations,” Pappas continued. “In Runkle there were some metals and some calcium and other salts but it wasn’t uh… we didn’t find it a problem for public health.”
“I nearly fell out of my seat when I heard Carey say that he found the same thing in Dayton Canyon that we did in Runkle Canyon, which is miles away on the other side of Rocketdyne,” Rev. Southwick told EnviroReporter.com after the meeting. “But what really upset me was Pappas just dismissing the finding out of hand and saying the substance was some harmless stuff no one should be concerned about.”
“While it is laudable that DTSC would test the rock with white precipitate out of Runkle Canyon and then give the Radiation Rangers the results, it is unfathomable that these folks didn’t see that the stuff has so much chromium and is obviously not natural — just look at it!” Southwick said. “I am completely discouraged because we have so much faith in Norm Riley. That chromium has to be broken down to see what it is exactly. And with what the Rangers and the city found last year with the arsenic and heavy metals, DTSC has to take this stuff as seriously as we do and get the science right.”