Halogenated flame retardants (HFRs) are ubiquitous in the environment, but little information is available about the bioaccumulation of HFRs in mangrove plants. In this study, three mangrove plant species were collected from Futian National Nature Reserve of Shenzhen City, South China to investigate the bioaccumulation of polybrominated diphenyl ethers (PBDEs) and several alternative halogenated flame retardants (AHFRs), including decabromodiphenyl ethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), hexabromobenzene (HBB), pentabromotoluene (PBT), tetrabromop-xylene (pTBX), pentabromoethylbenzene (PBEB) and dechlorane plus (DP). The mean concentrations of PBDEs, DBDPE, BTBPE, pTBX, PBT, PBEB, HBB and DP in mangrove plant species were 2010, 1870, 36.2, 18.7, 40.1, 17.8, 9.68 and 120 pg g⁻¹ dry weight, respectively. PBDEs were the dominant HFRs in mangrove plant tissues, followed by DBDPE. The relative abundance of BDE 209 in three mangrove plant tissues were much lower than those in sediments. Significant negative relationships between log root bioaccumulation factors and log Kₒw, and between log TFᵣ₋ₛ (from root to stem) and log Kₒw were observed, indicating that HFRs with low hydrophobicity were easily absorbed by mangrove roots and stems. A positive correlation between log TFₛ₋ₗ (from stem to leaf) and log Kₒw were found, suggesting that air-leaf exchange may occur in mangrove plants. This study highlights the uptake of HFRs by mangrove plants, which can be used as remediation for HFRs contamination in the environment.

Mosses are frequently used to monitor atmospheric metal contamination but few studies on metal adsorption under controlled conditions are available. Here, the accumulation of the heavy metals copper and zinc was studied in the acrocarp moss Atrichum undulatum. An in vitro culture of A. undulatum was established and the same line, size and equally old remets were exposed to six different treatments representing various metal exposure times and washing scenarios as rain simulation. The metal treatments were done in copper and zinc salts (Cu-acetate, CuSO4, ZnSO4 and ZnCl2, respectively). Energy-Dispersive X-ray microanalysis (EDX) was employed to detect bound heavy metals on the moss plantlets. Element distribution in stems and leaves was measured separately. The aqueous solution of metal salts facilitated an adsorption of both elements in the moss tissue as compared to solid medium. Furthermore, A. undulatum can tolerate pollution of zinc and copper in a distinctive extent; our data point towards a higher zinc tolerance whereas copper is rather harmful. However, semi-quantitatively, less zinc was detected within the moss tissue compared to copper. Interestingly, a strong positive correlation between the accumulation of copper/zinc and iron, and a strong negative correlation between copper/zinc and magnesium, respectively, was documented.

Herein, we investigated the effects of di-n-butyl phthalate (DBP) on photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) content, oxidative damage, and biomass accumulation of different tissues in wheat (Triticum aestivum L) planted in cinnamon soils. The photosynthetic or fluorescence parameters (except for the intercellular carbon dioxide concentration), chlorophyll content, RuBisCO content, and biomass of roots, stems, and leaves decreased at the seedling, jointing, and booting stages under the stress of DBP. Compared with the control, the content of superoxide anions and hydrogen peroxide in the roots, stems, and leaves increased with increasing DBP concentrations at the seedling, jointing, and booting stages. The activities of superoxide dismutase (SOD) and catalase (CAT) in the roots, stems, and leaves increased under the 10 and 20 mg kg−1 DBP treatments; however, no significant changes were observed under the 40 mg kg−1 DBP treatment at the seedling stage (except for the SOD activity in roots). The increase in SOD and CAT activities in the roots, stems, and leaves with increasing DBP concentration at the jointing and booting stages suggested that an increase in the activities of these antioxidant enzymes may play an important role in defending against excess reactive oxygen species under DBP stress. The biomass of wheat roots, stems, and leaves decreased with an increase in DBP concentration, which was presumably caused by a decrease in photosynthesis and RuBisCO. The effect of DBP on wheat roots, stems, and leaves decreased with wheat growth.

As the metabolites of tetrabromobisphenol A (TBBPA), tetrabromobisphenol A mono- and di-methyl ethers (TBBPA MME and TBBPA DME) have been detected in various environmental media. However, knowledge of the contribution of plants to their environmental fates, especially to the interactions between TBBPA DME and TBBPA, is quite limited. In this study, the metabolism and behaviors of TBBPA DME was studied with pumpkin plants through 15-day hydroponic exposure. The TBBPA were also studied separately using in-lab hydroponic exposure for comparison. The results showed that more TBBPA DME accumulated in pumpkin roots and translocated up to stems and leaves compared with TBBPA. Transformation of TBBPA DME occurred later and more slowly than that of TBBPA. Interconversion between TBBPA DME and TBBPA was verified in intact plants for the first time. Namely, TBBPA DME can be biotransformed to TBBPA MME (transformation ratio in mole mass, TRMM 0.50%) and to TBBPA (TRMM 0.53%) within pumpkin; and TBBPA can be biotransformed to TBBPA MME (TRMM 0.58%) and to TBBPA DME (TRMM 0.62%). In addition, two single benzene-ring metabolites, 2,6-dibromo-4-(2-(2-hydroxyl)-propyl)-anisole (DBHPA, TRMM 3.4%) with an O-methyl group and 2,6-dibromo-4-(2-(2-hydroxyl)-propyl)-phenetole (DBHPP, TRMM 0.57%) with an O-ethyl group, were identified as the transformation products in the TBBPA exposure experiments. The transformation and interconversion from TBBPA DME back to TBBPA is reported as a new pathway and potential source for TBBPA in the environment.

Little information exists concerning the long-term interactive effect of nitrogen (N) addition with phosphorus (P) and potassium (K) on Sphagnum N status. This study was conducted as part of a long-term N manipulation on Whim bog in south Scotland to evaluate the long-term alleviation effects of phosphorus (P) and potassium (K) on N saturation of Sphagnum (S. capillifolium). On this ombrotrophic peatland, where ambient deposition was 8 kg N ha−1 yr−1, 56 kg N ha−1 yr−1 of either ammonium (NH4+, Nred) or nitrate (NO3−, Nox) with and without P and K, were added over 11 years. Nutrient concentrations of Sphagnum stem and capitulum, and pore water quality of the Sphagnum layer were assessed. The N-saturated Sphagnum caused by long-term (11 years) and high doses (56 kg N ha−1 yr−1) of reduced N was not completely ameliorated by P and K addition; N concentrations in Sphagnum capitula for Nred 56 PK were comparable with those for Nred 56, although N concentrations in Sphagnum stems for Nred 56 PK were lower than those for Nred 56. While dissolved inorganic nitrogen (DIN) concentrations in pore water for Nred 56 PK were not different from Nred 56, they were lower for Nox 56 PK than for Nox 56 whose stage of N saturation had not advanced compared to Nred 56. These results indicate that increasing P and K availability has only a limited amelioration effect on the N assimilation of Sphagnum at an advanced stage of N saturation. This study concluded that over the long-term P and K additions will not offset the N saturation of Sphagnum.

Uptake and translocation of imidacloprid (IMI), thiamethoxam (THX) and difenoconazole (DFZ) in rice plants (Oryza sativa L.) were investigated with a soil-treated experiment at two application rates: field rate (FR) and 10*FR under laboratory conditions. The dissipation of the three compounds in soil followed the first-order kinetics and DFZ showed greater half-lives than IMI and THX. Detection of the three compounds in rice tissues indicated that rice plants could take up and accumulate these pesticides. The concentrations of IMI and THX detected in leaves (IMI, 10.0 and 410 mg/kg dw; THX, 23.0 and 265 mg/kg dw) were much greater than those in roots (IMI, 1.37 and 69.3 mg/kg dw; THX, 3.19 and 30.6 mg/kg dw), which differed from DFZ. The DFZ concentrations in roots (15.6 and 79.1 mg/kg dw) were much greater than those in leaves (0.23 and 3.4 mg/kg dw). The bioconcentration factor (BCF), representing the capability of rice to accumulate contaminants from soil into plant tissues, ranged from 1.9 to 224.3 for IMI, from 2.0 to 72.3 for THX, and from 0.4 to 3.2 for DFZ at different treated concentrations. Much higher BCFs were found for IMI and THX at 10*FR treatment than those at FR treatment, however, the BCFs of DFZ at both treatments were similar. The translocation factors (TFs), evaluating the capability of rice to translocate contaminants from the roots to the aboveground parts, ranged from 0.02 to 0.2 for stems and from 0.02 to 9.0 for leaves. The tested compounds were poorly translocated from roots to stems, with a TF below 1. However, IMI and THX were well translocated from roots to leaves. Clothianidin (CLO), the main metabolite of THX, was detected at the concentrations from 0.02 to 0.5 mg kg−1 in soil and from 0.07 to 7.0 mg kg−1 in plants. Concentrations of CLO in leaves were almost 14 times greater than those in roots at 10*FR treatment.

Many pharmaceutical and personal care products (PPCPs) and endocrine-disrupting chemicals (EDCs) are present in reclaimed water, leading to concerns of human health risks from the consumption of food crops irrigated with reclaimed water. This study evaluated the potential for plant uptake and accumulation of four commonly occurring PPCP/EDCs, i.e., bisphenol A (BPA), diclofenac sodium (DCL), naproxen (NPX), and 4-nonylphenol (NP), by lettuce (Lactuca sativa) and collards (Brassica oleracea) in hydroponic culture, using 14C-labeled compounds. In both plant species, plant accumulation followed the order of BPA > NP > DCL > NPX and accumulation in roots was much greater than in leaves and stems. Concentrations of 14C-PPCP/EDCs in plant tissues ranged from 0.22 ± 0.03 to 927 ± 213 ng/g, but nearly all 14C-residue was non-extractable. PPCP/EDCs, particularly BPA and NP, were also extensively transformed in the nutrient solution. Dietary uptake of these PPCP/EDCs by humans was predicted to be negligible.

The effects of the ionic liquid 1-octyl-3-methylimidazolium chloride ([OMIM]Cl) was studied in hydroponically grown rice seedlings. Observed effects included increased root length and weight at concentrations of 0.1 mg/L [OMIM]Cl, however, as concentrations increased a reversed response was observed where roots and stems grew shorter and the weight decreased. The inhibitory concentration 50 (IC50,5d) values for root length and stem length were 0.59 mg/L and 0.70 mg/L, respectively. The Hill reaction activity and root system activity in [OMIM]Cl-treated rice seedlings were observed to be lower than the controls, however, root membrane permeability increased. The antioxidant enzyme activity in roots decreased, while in leaves there was an initial stimulation followed by a decrease. Malondialdehyde (MDA) content was found to be greater in seedlings subjected to [OMIM]Cl treatment. The cellular structures, such as chloroplasts, mitochondria and rough endoplasmic reticulum in rice root and leaf cells were affected at concentrations of 0.6 mg/L [OMIM]Cl.

Rhizosphere soil and dominant plant samples were collected at a brownfield site in New Jersey, USA, during summer 2005 to evaluate plant metal uptake from the contaminated soils. Metal concentrations varied from 4.25 to 978 μg g⁻¹ for As, 9.68–209 μg g⁻¹ for Cr, 23.9–1870 μg g⁻¹ for Cu, and 24.8–6502 μg g⁻¹ for Zn. A wide range of metal uptake efficiencies in the roots, stems and leaves was found in this study. Data showed that (1) Betula populifolia has high Zn, Cu and As accumulations in the root, and high concentrations of Cu and Zn in the stem and the leaf; (2) Rhus copallinum has high accumulation of Zn and Cr in the leaf and Cu in the stem; (3) Polygonum cuspidatum has high accumulations of Cu and As in the root; and (4) Artemisia vulgaris shows high Cu accumulation in the leaf and the stem.

Consequences of irrigation by arsenic (As) enriched groundwater were assigned in the Hetao Plain, part of Chinas’ Inner Mongolia Autonomous Region. Examinations followed the As flow path from groundwater to soil and finally plants. A sunflower and a maize field were systematically sampled, each irrigated since three years with saline well water, characterized by elevated As concentrations (154 and 238μgL⁻¹). The annual As input per m² was estimated as 120 and 186mg, respectively. Compared to the geogenic background, As concentrations increased toward the surface with observed enrichments in topsoil being relatively moderate (up to 21.1mgkg⁻¹). Arsenic concentrations in plant parts decreased from roots toward leaves, stems and seeds. It is shown that the bioavailability of As is influenced by a complex interplay of partly counteracting processes. To prevent As enrichment and soil salinization, local farmers were recommended to switch to a less problematic water source.