Search

The uptake and distribution of copper, zinc, arsenic, and lead was examined in two rare Australian saltmarsh species, Tecticornia pergranulata and Wilsonia backhousei. The bioconcentration factors and translocation factors were generally much lower than one, except for the Zn translocation factors for T. pergranulata. When compared to other Australian saltmarsh taxa, these species generally accumulated the lowest levels observed among taxa, especially in terms of their BCFs. Essential metals tended to be regulated, while non-essential metals increased in concentration with dose during transport among compartments, a pattern not previously observed in Australian saltmarsh taxa. The uptake of metals into roots was mainly explained by total sediment metal loads as well as more acidic pH, increased soil organic matter, and decreased salinity. The low uptake and limited translocation observed in these rare taxa may offer a competitive advantage for their establishment and survival in the last urbanised populations, where legacy metal contamination acts as a selective pressure., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Halophytes residing in metal-contaminated saltmarsh habitats may employ strategies to enhance fitness of the next generation. We aimed to test the hypothesis that Juncus acutus individuals inhabiting metal-contaminated locations would experience elevated tolerance of offspring to metals compared to plants residing in locations with no metal contamination history. J. acutus seeds (F 1 generation) were collected from F 0 parent plants residing at eight locations of a contemporary sediment metal gradient (contaminated to uncontaminated) across the coast of NSW, Australia (Hunter river, Lake Macquarie and Georges River). Seeds were exposed in the laboratory to incremental Zn (0.0-1.6 mM) and Pb (0.0-0.50 mM) for nine (9) days, and % germination, germination rate, root elongation and vigour index were assessed for the determination of tolerance. Greater root accumulation (BCF = 1.01) of Zn and subsequent translocation to aerial parts (culm BCF = 0.58 and capsule BCF = 0.85) were exhibited in parents plants, whereas Pb was excluded from roots (BCF = 0.60) and very little translocation to aerial portions of the plant was observed (culm BCF = 0.02 and capsule BCF = 0.05). F 1 offspring exhibited tolerance to Zn with EC 50 (% germination) significantly correlated with their parents' culm (R 2  = 0.93, p = 0.00) and capsule (R 2  = 0.57; p = 0.03) Zn. No correlations were observed between offspring Pb tolerance and Pb in parents' plant tissues. Enhanced tolerance to the essential metal Zn may be because Zn is very mobile in the parent plant and seeds experience greater Zn load as a significant portion of sediment Zn reaches capsules (85%). Thus, Zn tolerance in J. acutus seeds is likely attributable to acclimation via maternal transfer of Zn; however, further manipulative experiments are required to disentangle potential acclimation, adaptation or epigenetic effects in explaining the tolerance observed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

This study assessed the appropriate sampling design required for quantifying variability in metal accumulation in the leaf tissues of A. marina, a dominant mangrove inhabiting Australian estuaries, by applying a hierarchical nested sampling design to sample mangroves at various levels of biological and spatial hierarchies (leaf, branch, tree, site). It was revealed that most variation in metal accumulation occurred among trees and branches, with insignificant variation between sites and among leaves. We also examined the accumulation of metal (loid)s in the leaf tissues collected from six locations across the Georges River estuary in southern Sydney, which differ in metal contamination history. Prospect Creek and Salt Pan Creek were the most contaminated locations, which exceeded sediment quality guideline values for Cu (66.71 ± 2.18 μg/g), Zn (317.14 ± 46.14 μg/g) and Pb (81.02 ± 2.79 μg/g). All metal(loid) concentrations in leaf tissues were much lower than their concentrations in sediment, but essential metals exhibited greater mobility. Out of 10 metal(loid)s, Mn, Co and Pb in leaves showed linear relationships (R 2  = 0.28-0.47) with sediment, indicating that mangrove leaves may be used as a bioindicator of environmental loads for these metals., (Copyright © 2022 Elsevier Inc. All rights reserved.)

We examined the patterns of uptake and partitioning of metal(loid)s in Suaeda australis from three highly urbanised estuaries (Sydney Olympic Park, Hunter Wetlands and Lake Macquarie) in NSW, Australia. Of these, Sydney Olympic Park was found to be the most contaminated estuary in terms of combined sediment metal(loid) load, followed by Hunter Wetlands and lowest in Lake Macquarie (via PERMANOVA). Uptake in roots was greater for the essential metals Cu and Zn along with the non-essential metal Cd and the metalloid Se (root BCFs >1) and lower for Pb and As (root BCFs <1). Substantial barriers for translocation from roots to stems were identified for all metal(loid)s (stem TFs; 0.07-0.68). Conversely, unrestricted flow from stems to leaves was observed for all metal(loid)s at unity or higher (leaf TFs ≥ 1). Strong linear relationships between sediment and root for Zn and Pb were observed, indicating roots as a useful bioindicator., (Copyright © 2021 Elsevier Ltd. All rights reserved.)