Water compositional evolution around a historic asbestos mine, Troodos mountains, Cyprus

The historic Amiantos chrysotile asbestos mine (closed 1988) in the Troodos mountains, is hosted in serpentinites that constitute the Artemis Diapir. Host rocks were extensively sheared and brecciated during Pleistocene-Holocene diapiric uplift, enabling penetration of meteoric waters. Veins of serpentine minerals, especially fibrous chrysotile, have formed throughout this uplift history with accompanying carbonates, and carbonate surface precipitates that form at spring sites. The Artemis Diapir is juxtaposed by faults against less-permeable partially serpentinised peridotites of the Olympus Diapir that forms the highest elevation (1952 m) of the Troodos Mountains. Streams and shallow groundwater draining the Artemis Diapir have high concentrations of Mg²⁺ and dissolved inorganic carbon (DIC), minor Ca²⁺, and pH 8–10. In addition, these waters have high concentrations of Na⁺, K⁺, Cl⁻, SO₄²⁻ and trace elements Cs, Ba, Br, B, and Li sourced from the dissolution of mineral inclusions in the host serpentinites. These dissolved constituents overprint low levels of marine aerosols that occur in local meteoric precipitation. Passage of surficial waters through asbestos mine tailings have locally enhanced dissolution of these elements because of even higher permeability and small particle size that resulted from mine-related comminution. All surficial waters are strongly supersaturated with respect to chrysotile (log Q/K = 3–9) and carbonate minerals, especially magnesite (log Q/K = 1–2). Evaporative carbonate precipitates form episodically on stream beds and tailings surfaces during dry seasons. Erosion of mine tailings and friable host rocks by rain events in the steep mountain environment contributes detrital chrysotile asbestos to stream sediments, with potential for aeolian remobilization. The relatively high abundance of carbonates already in the rocks and mine residues, combined with carbonate and chrysotile supersaturation in surficial waters, limits the efficacy of these materials for CO₂ capture through enhanced weathering and mineral carbonation.