Accumulation of Arsenic by Plants Growing in the Sites Strongly Contaminated by Historical Mining in the Sudetes Region of Poland

Abstract

The uptake of As by various plants growing in highly enriched sites was examined in order to identify potential As accumulators and to assess the risk associated with As presence in plant shoots. Representative samples of 13 plant species, together with soil samples, were collected from various sites affected by historical As mining: mine and slag dumps, tailings and contaminated soils with As concentrations in a range 72–193,000 mg/kg. Potentially and actually soluble As forms, extracted with 0.43 M HNO3 and, 1M NH4NO3 were examined in relation to As concentrations in plant roots and shoots. The latter differed strongly among the species and within them and were in the ranges 2.3–9400 mg/kg and 0.5–509 mg/kg, respectively. The majority (over 66%) of plant samples had As shoot concentrations above 4 mg/kg, an upper safe limit for animal fodder. The uptake of As by plants correlated well with total and extractable soil As, though As concentrations in plants could not be predicted based on soil parameters. Equisetum spp. and C. epigejos indicated a particularly strong accumulation of As in shoots, while A. capillaris, and H. lanatus showed a limited As root-to-shoot transfer, apparently associated with species-related tolerance to As.

Arsenic pollution in Quaternary sediments and water near a former gold mine

“…6 ). Consequently, in croplands, bioaccumulation of As in plant shoots and roots of dry fodder has been found to exceed permissible content levels for animal feed 91 , 92 . Moreover, As content (72–451 mg/kg) in soils in allotment gardens suppling inhabitants of Złoty Stok with fruits and vegetables markedly exceeds soil quality limits 37 .…”

Arsenic Uptake by Two Tolerant Grass Species: Holcus lanatus and Agrostis capillaris Growing in Soils Contaminated by Historical Mining

“…The study was carried out in sites situated in three historical arsenic mining centers in the Sudetes: Złoty Stok, Radzimowice and Czarnów. More detailed characteristics of their locality were provided in previous papers [9,12,43]. The sites under study included typical hay meadows, wastelands and reclaimed mine waste dumps fully or partly covered by herbaceous and grassy vegetation.…”

“…Air-dried soil samples from the field and from the greenhouse study were homogenized, ground, sieved to 2 mm and analyzed using standard methods applied in soil science, as described previously [12,43]. "Pseudototal" concentrations of As in soils (called "total"), were determined after microwave soil digestion with aqua regia (HNO 3 + HCl), following ISO 14466.…”

“…Interpretation of data involved the calculations of transfer, bioaccumulation and bioconcentration factors (TF, BAF and BCF) that were defined and discussed in details in the previous papers [12,43]. Briefly, TF was calculated as the ratio of As concentration in grass shoots to roots.…”

“…Arsenic was produced there until 1962. Mine wastes and tailings that have remained in those areas contain high concentrations of As, up to 1 percent or even higher [9][10][11][12]. Consequently, the soils that developed in mine sites and in their surroundings are locally highly enriched in As.…”