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Southern California is a mega-metropolitan area with abundant air pollution, complex geology, and diverse Mediterranean ecosystems. The objective of this study was to evaluate trace metal and metalloids (TMMs) (As, Cd, Co, Cr Cu, Ni, Pb, U, V, Zn) in soils and foliage of peri-urban areas and explore potential effects from human-development, ecosystems, and geologic material. Foliage of dominant native vegetation, soil samples (0–20 cm), saprolite, and unweathered rock samples were collected across fifty-four sampling sites in foothills spanning coastal Los Angeles and Orange counties to inland San Bernardino and Riverside counties. Soil As, Cd, Cu, and Pb concentrations were regionally elevated, but not as elevated as point-source polluted sites elsewhere. Soil Cd, Cr, Cu, Pb, and Zn concentrations were above EPA Ecological Soil Screening Levels. Further, enrichment factors (EF) normalized to Ti concentrations in bedrock suggest minor to moderate As, Cd, Cr, Cu, Pb, and V accumulation in soils. Our foliar TMM concentrations and bioaccumulation factors (BAF) (foliar and soil ratio) indicate no bioaccumulation and limited effects across geologic, development intensity, and ecosystems groups. Sedimentary-derived soils affected soil TMMs, but likely not through inheritance of TMMs but by promoting clay and organic matter availability. Proximity to higher development intensity resulted in As, Cd, Cr, Cu, and Pb accumulation in peri-urban soils. Foliar TMM concentrations and BAFs suggest geologic materials, human development, and ecosystem properties were not important factors and TMMs were likely controlled by plant uptake or ecophysiology.

Fragmented ultramafic bodies in New England were important mineral resources until the early twentieth century, yet few studies have addressed their potential to release trace metals to terrestrial and aquatic environments. Here, we evaluate the release of four trace metals (Cr, Co, Mn, and Ni) from a historic serpentine–talc “soapstone” quarry in Blandford, MA, USA. Soil pits, sediment and rock samples, and stream water samples were collected from upslope undisturbed areas, within the mine spoils and mine face, and downslope of the mine. In order to provide a bottom-up approach for understanding metal release, careful petrographic analysis, electron-dispersive spectroscopy, and wavelength-dispersive spectroscopy were employed to provide first-order insight into the mineralogy of the deposit and a determination of potential metal-bearing phases. Trace metals were primarily observed in ultramafic sheet silicates, primary Fe-oxides, and interstitial weathering-related sulfates. Bulk rock concentrations were Cr (1550 mg kg−1), Co (230 mg kg−1), Mn (1100 mg kg−1), and Ni (1960 mg kg1); Cr, Co, and Ni were elevated relative to the surrounding country rock. However, soils and sediments total concentrations were comparable to background soil concentrations: Cr (119 mg kg−1), Co (73 mg kg−1), Mn (894 mg kg−1), and Ni (65 mg kg−1). Moreover

Shale is an important lithology globally due to its wide spatial abundance and potentially high trace metal and metalloid (TMM) geochemistry, which can be potentially inherited by its overlying soils. Unlike other soils, shale-derived soils inherit organic matter and oxides (Fe and Mn) which promote accumulation and retention of both geogenic and exogeneous TMMs. Here, we explore TMMs in seven grey shales weathering profiles along a north–south transect spanning the western flank of the Appalachian Mountains from New York to Tennessee. Overall, total TMM concentrations in the grey shales and their soils were below concentrations known to be toxic and below concentrations observed in black shales. Tau values show that shale-derived soils are net accumulators of many TMMs (As, Cd, Co, Cu, Ni, Pb, Sb, Sn and Zn) but others (Cr, W, and V) showed a net depletion. Many of the TMMs had high proportions (5–50%) that were sequestered in reducible phases (amorphous and crystalline Fe oxides) but few TMMs were associated with oxidizable phases (organic matter, reduced minerals). Sulfides and oxides (Mn nor Fe) were not detected by X-ray diffraction (