Twelve Mediterranean hydrophyte species collected inLebanon were evaluated for their potential asbioindicator species for heavy metal pollution innutrient cultures enriched with 1 ppm Cr, Ni and Cd.These were: Nasturtium officinale R.Br, Apium nodiflorum L., Veronica beccabunga L., Veronica anagallis aquatica L., Veronicalysimachioides L., Veronica anagalloides L., Mentha longifolia L., Mentha aquatica L., Mentha pulegium L., Potentilla reptansL., Mentha sylvestris L., and Cardamine uliginosa L.. Large variability in responseto exposure to the heavy metals was observed. Growthrates remained high during the experimental period,indicating that the plants were little affected by thepresence of the metal at the experimentalconcentration. Metal accumulation and bioconcentrationvaried within at least one order of magnitude, andranged from less than 10 to over 200. Cr waspreferentially accumulated in the roots. All speciesbut M. pulegium, P. reptans and V. anagallisaquatica accumulated and bioconcentrated sufficientCr to qualify as bioindicator species. Five of thespecies that accumulated Cr also accumulated Ni, withthe same partitioning into the root. These were: N. officinale, C. uliginosa sp., M. longifolia, M. aquatica and M. sylvestris, all of which mayalso be used as bioindicators of Ni pollution. Onlyone species, M. aquatica, accumulated Cdsignificantly, and may, therefore, be used as abioindicator for all three metals.

In this work, we investigated the degradation of the mixture of acid yellow 36 and acid blue 80 via photoperoxidation (PP/UV-C) and via electrochemical oxidation (EAOP). After optimization, the best results were obtained using [H₂O₂] = 80 mg‧L⁻¹ for PP/UV-C and concentrations of 0.05 mol∙L⁻¹ of the electrolytes (Na₂SO₄ and KCl) for EAOP/UV-C. For PP/UV-C, complete degradation of the monitored groups was obtained for all 3 λ. For the electrochemical systems, the higher degradation efficiency was achieved by using UV-C radiation associated with the electrochemical absorption process (EAOP/UV-C), reaching 75% for 267 nm and 100% for the other λ from 180 min. A kinetic monitoring by HPLC analytical technique was performed in order to visualize the possible reaction intermediates, as well as the consumption of H₂O₂ and the production of chlorine compounds as oxidizing agents of the applied processes. The toxicity evaluation against Nasturtium officinale, Daucus carota subsp. Sativus, and Thymus vulgar seeds and for Escherichia coli showed the presence of intermediate species of the dyes due to a certain degree of post-treatment toxicity. It was concluded that the use of the PP/UV-C and EAOP processes was efficient for the degradation of the dyes studied, although the system must be further improved to achieve better mineralization.

This study aimed to evaluate the health risks of cadmium (Cd), lead (Pb), inorganic arsenic (As), and nitrate exposure through the consumption of bivalves and vegetables collected from local markets in Ho Chi Minh City. The present study analyzed four favorite bivalve species (Meretrix lyrate; Perna viridis; Anadara subcrenata; Anadara granosa) for concentrations of Cd, Pb, and inorganic As and 9 vegetable species (Brassica juncea; Brassica integrifolia; Brassica rapa chinensis; Nasturtium officinale; Lactuca sativa; Ipomoea aquatica; Amaranthus gangeticus; Ipomoea batatas; Spinacia oleracea) for concentrations of Pb and nitrate. The target hazard quotient (THQ) and target cancer risk (TR) were calculated to estimate non-carcinogenic and carcinogenic health risks, respectively. For bivalves, Cd and inorganic As were present at relatively lower concentrations, whereas a relatively higher accumulation of Pb was recorded. The THQ for Cd, Pb, or inorganic As was below the threshold of 1, suggesting no potential health risks. In the case of vegetables, Pb was present at relatively low concentrations, while nitrate accumulation was at relatively high concentrations. The THQ for nitrate was higher than the threshold of 1, suggesting a potential health risk. The combined effects are estimated according to the hazard index (HI), which shows the health risks associated with the consumption of these bivalves and vegetable species. Therefore, continuous and excess consumption for a lifetime of more than 70 years has a probability of target cancer risk.

Biomarkers such as oxidase enzyme activity from flora exposed to chemicals in the water column and sediments have been widely used by ecotoxicologists to assess the quality of an environment. Biomarkers such as oxidase enzymes are especially useful indicators because they represent a direct biological response to environmental toxicity. A luminometer was used to quantify oxidase enzyme production in watercress (Nasturtium officinale) due to toxic chemical exposure of E85 (85% ethanol and 15% gasoline blend), gasoline, and 99% pure ethanol over a 72-h period in aquatic root exposure and volatile leaf exposure experiments. Aquatic exposure to E85 caused an increase in oxidative enzyme production while gasoline and ethanol caused no significant changes in oxidase concentrations. Aquatic root exposure results were compared to volatile leaf exposures where effects of E85, gasoline, and ethanol caused increases in oxidase production. Morphometric measurements were also conducted as plant stress comparisons to oxidative enzyme analyses. Measurements of root length showed increases in root growth at some concentrations of fuels with only the highest concentration of E85 resulting in a decrease in root growth when compared to the control.

Copper is an active component of some commercial algaecides and is commonly found in low concentrations in contaminated aquatic systems. Unintended consequences of algaecide application include macrophyte bioaccumulation and possible trophic level bioamplification especially by specialist herbivores. Trophic level effects of copper contamination were observed through feeding trials using the mustard beetle (Phaedon viridis). Several metals, including copper, interfere with the myrosinase enzyme system responsible for the watercress (Nasturtium officinale) allelopathic defense against herbivory. The mustard beetle is a specialist herbivore that has evolved a detection system that is stimulated by the products of the glucosinolate-myrosinase system. Because copper interferes with myrosinase enzymes, mustard beetles were expected to avoid copper-contaminated plants. While larvae exhibited a slight preference for contaminated plants, adult mustard beetles in this experiment exhibited a statistically significant preference for plants uncontaminated with copper.

This study investigated the potential of horizontal subsurface flow constructed wetlands (HSSF-CWs) and open raceway ponds (RWPs) operated under different regimes (plants, impregnated activated charcoal (IAC), and algae) for long-term nitrogen removal to control eutrophication problems. For experimental purposes, five mesocosms HSSF-CWs and two RWPs were set up in Wuxi, China, a temperate climate zone. Three HSSF-CW units were cultivated with different regions’ plant species including Nasturtium officinale, Juncus effusus, and Brassica juncea, whereas the one unit packed with IAC and the fifth was left as a control, while two species of algae (Spirogyra and C. pyrenoidosa) were cultured in RWPs. All the amendments tested in this study were almost equally effective for long-term nitrogen removal. The results demonstrated that more than 75.7, 88, and 66%, removal of TN, [Formula: see text]–N, and [Formula: see text]–N was achieved by the HSSF-CWs, packed with IAC and N. officinale. Concerning RWPs, both algal species showed almost similar results but slightly lower than others, which may be attributed to the less compatibility with the environment. It was observed that nitrogen removal performance was higher in the winter-spring (March–April) season as compared with winter (January–February). Moreover, all plants, particularly N. officinale growth, were quite steadier than others. The present study validates the impression that both treatment systems were potentially effective in long-term nitrogen removal from sewage and could be considered beneficial to control the eutrophication. Graphical Abstract

The growth and cadmium (Cd) accumulation of emergent plant Nasturtium officinale R. Br. cuttings taken from plants grafted onto rootstocks of four terrestrial Cruciferae species were studied in a pot experiment. Scions from N. officinale seedlings were grafted onto rootstocks of Brassica chinensis L., Raphanus sativus L., Brassica napus L., and Rorippa dubia (Pers.) H. Hara. Cuttings were taken after 1 month and grown in Cd-contaminated soil (10 mg Cd kg⁻¹) for 60 days. Compared with non-grafted N. officinale, grafting onto R. sativus and B. napus rootstocks increased the root, shoot, and whole plant biomasses of N. officinale cuttings. Brassica napus rootstock was more effective than R. sativus rootstock for increasing the biomass of N. officinale cuttings. The four rootstocks decreased or had no significant effect on photosynthetic pigment contents in N. officinale cuttings compared with non-grafted N. officinale. Only grafting onto B. napus rootstock enhanced antioxidant enzyme activities. Compared with non-grafted N. officinale, R. sativus and B. napus rootstocks decreased the Cd contents in roots and shoots of N. officinale cuttings, whereas the other rootstocks had no significant effect on the shoot Cd content. The four rootstocks had no increase effects on Cd extraction by N. officinale cuttings. Therefore, cutting after grafting did not enhance the phytoremediation ability of N. officinale for growth in Cd-contaminated soil. However, R. sativus and B. napus rootstocks decreased the Cd content in N. officinale cuttings, which offers a potential approach for N. officinale safety production as a wild vegetable in Cd-contaminated soils.

Choosing native vascular plants as nutrient and toxic element accumulators for passive biomonitoring of urban river quality is not an easy task in Mediterranean rivers, due to the particular climate determining high variations in river hydrology. To identify potential biomonitors for this area, the roots of seven species (Angelica sylvestris, Apium nodiflorum, Tradescantia fluminensis, Nasturtium officinale, Persicaria lapathifolia, Arctium lappa, Typha latifolia), growing in seven sites along the River Irno (Southern Italy), were collected in July 2010 and analyzed regarding their capability to accumulate Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, and Zn through atomic absorption spectrometry. Notwithstanding the expected different accumulation degree among the species, they highlighted similar spatial contamination gradients, and all of them appeared suitable, alone or in combination, for river passive biomonitoring. A. nodiflorum, in particular, appeared the best biomonitor for the River Irno, where severe anthropogenic impacts were detected: high Cu and Cd contamination from vine cultivation in the upper stretch, and Pb, Zn, and Mn contamination in the medium stretch from airborne dusts coming from a cast iron foundry.

Many studies have demonstrated the effectiveness of algicidal compounds produced by macrophytes against microalgae. The aim of this study was to assess the algicidal activity of seven Moroccan macrophyte ethyl acetate extracts (MEA) to control harmful algal blooms (HABs). The response and sensitivity of prokaryotic toxic cyanobacteria (Microcystis aeruginosa) and eukaryotic microalgae (Chlorella sp.) were highlighted. The algicidal effect of MEA extracts against the two microalgae was assessed using both the paper disc diffusion and microdilution methods. This last was used in order to evaluate the minimum inhibitory concentrations (MIC) and minimum algicidal concentrations (MAC). Results showed that the growth of both microalgae was significantly inhibited by all MEA extracts. Myriophyllum spicatum organic extract shows the highest growth inhibition activity against M. aeruginosa (35.33 ± 1.53) and Chlorella sp. (30.33 ± 1.15 mm). This stronger inhibitory activity was confirmed by the low MIC (6.25, 12.5 mg/L) and MAC (6.25, 12.5 mg/L) values. Furthermore, results showed different sensitivity between the prokaryotic and eukaryotic microalgae into MEA extracts. Based on the MIC and MAC values, we can distinguish two groups of plants. The first one, including M. spicatum, Ranunculus aquatilis, and Enteromorpha sp., can be considered as a preferable anti-prokaryotic group with a stronger inhibitory activity on M. aeruginosa growth. The second group, constituted by Potamogeton natans, Nasturtium officinale, Elodea sp., and Ceratophyllum sp., has a preferable and stronger inhibitory effect against eukaryotic algae (Chlorella sp.). Overall the results reveal the potential algicidal activity of macrophytes and suggested that MEA extracts could play an important role in biocontrol of HABs.

The purpose of this study is to determine whether the allelopathy of living Myriophyllum aquaticum and its straw has the same effects; two pot experiments were conducted to study the effects of intercropping using M. aquaticum and its straw on the growth and cadmium (Cd) accumulation of Nasturtium officinale. Different planting ratios (1:3, 2:2 and 3:1) of N. officinale and M. aquaticum led to an increase in the biomass of both plant species and increased the Cd content in roots and shoots of N. officinale, but led to a reduction in the Cd content in roots and shoots of M. aquaticum. When the intercropping ratio of N. officinale and M. aquaticum was 3:1, the Cd amount in whole plants reached the maximum of 293.96 μg pot⁻¹. Mulching the straw of M. aquaticum roots on the soil surface increased the biomass of N. officinale, but mulching the straw of M. aquaticum stems and leaves led to a decrease. Mulching the straw of roots, stems and leaves of M. aquaticum reduced Cd content and amounts in roots and shoots of N. officinale. Intercropping with M. aquaticum can improve the Cd uptake ability of N. officinale, but mulching M. aquaticum straw can reduce its Cd uptake ability.