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Allelochemicals from macrophytes or other organisms that inhibit microalgal growth have gained great interest due to their environmental potential as algaecides in controlling water blooms or red tide [1]. In aquatic ecosystems, varieties of submerged macrophytes were found to effectively inhibit the growth of blue-green algae [2]. For example, Myriophyllum spicatum [3][4][5], Vallisneria spiralis [2], Potamogeton crispus [6], Ceratophyllum demersum, and Najas marina [7] showed allelopathic effects on nuisance algae. Xian et al. [2] found that six allelochemicals (2-ethyl-3-methylmaleimide, dihydroactinidiolide, 4-oxo-β-ionone, 3-hydroxy-5, 6-epoxy-β-ionone, loliolide, and 6-hydroxy-3-oxo-α-ionone) and an unknown compound from V. spiralis had strong inhibitory effects on Microcystis aeruginosa Kütz. M. spicatum could release ellagic acid, gallic acid, pyrogallic acid, (+)-catechin, hydrolyzable tannin (eugeniin) and β-1,2,3-tri-O-galloyl-4,6-(S)-hexahydroxydiphenoyl-D-glucose (tellimagrandin II) into the culture solution, which inhibits the growth of M. aeruginosa Pol. J. Environ. Stud. Vol. 24, No. 1 (2015), [333][334][335][336][337][338] AbstractEutrophication of water due to pollution is one of the most serious environmental problems. The occurrence of toxic cyanobacterial blooms in eutrophic lakes, reservoirs, and recreational waters has become a worldwide problem. The inhibitory allelopathy of plants on harmful algae, which has drawn extensive attention recently, is low-cost and ecologically safe, and some good results have been reported. In this study, volatile organic compounds as major allelochemicals have been isolated from some aquatic plants and identified. The chemical compositions of essential oil isolated from Potamogeton cristatus, Potamogeton maackianus, Potamogeton lucens, Vallisneria spinulosa, Ceratophyllum demersum, and Hydrilla verticillata were analyzed by GC/MS. Thirty components were identified in the oils, mainly including fatty acids, ester, sterol, and ketone, etc. Inhibitory effects of essential oils on Microcystis aeruginosa were also investigated. The inhibition ratio of essential oils on M. aeruginosa was 30.2-41.7% when the treatment concentration of extracts was at a level of 50.0 mg/L. Hence, the essential oils isolated exhibited a significant anti-cyanobacterial activity.

A novel chitosan/aluminum sludge composite aerogel was fabricated. It's capacity was up to 434.64 mg g−1. It has good selectivity for U(vi) when multiple ions coexist. U(vi) uptake was due to surface complexation.

Eutrophication is a worldwide problem in aquatic ecosystems and cyanobacterial blooms can cause severe water quality deterioration due to toxin production, hypoxia, off-flavor problems that lead to illness in animals and humans [1][2][3]. Therefore, the removal of harmful cyanobacterial blooms is a crucial step for the maintenance of safe water supplies and for the safety of aquatic products [4]. Recent years have seen many studies relating to the isolation and identification of allelochemicals from aquatic plants [5][6][7][8], while the algicidal properties of terrestrial plants still get less attention [9]. Up to now, the extracts of many terrestrial plants also show inhibitory effects against cyanobacteria, such as barley straw [10][11][12][13], Chinese traditional medicines [9,14,15], and so on.Pomegranate (Punicagranatum), belonging to the family Punicaceae [16], is one of the oldest edible fruits. It has been cultivated extensively in Mediterranean countries, Iran, India, and to some extent in the U.S. (California), China, Japan, and Russia [17]. Pomegranate peels and seeds Pol. J. Environ. Stud. Vol. 24, No. 4 (2015), 1803-1807 AbstractMany studies have involved the isolation and identification of allelochemicals from aquatic plants, but the algicidal properties of terrestrial plants have received less attention. This study aims to identify allelochemicals of ethyl acetate extracts from three plant materials (shaddock peel, pomegranate peel, pomegranate seed) and to investigate their inhibitory effects on Microcystis aeruginosa. The ethyl acetate extracts of the three plant materials were identified by GC-MS. Finally, 19 kinds of compounds (including organic acids, ester, ketone, sterol, etc.) were obtained and eight kinds of organic acids and N-phenyl-2-Naphthalenamine were proved to be allelochemicals. The inhibitory effects of the ethyl acetate extracts were also explored by M. aeruginosa bioassay. This showed that the inhibition percentages of ethyl acetate extracts of the three plant materials on the growth of M. aeruginosa were 43.9%, 47.5%, and 40.3%, respectively, when the algae were treated at a dosage of 20 mg/L extracts.Keywords: allelopathic effect, shaddock peel, pomegranate peel, pomegranate seed, Microcystis aeruginosa *e-mail: zhanglieyu@163.com **e-mail: shpcheng@foxmail.com DOI: 10.15244/pjoes/36986 as a byproduct of pomegranate processing are about 26-30%, 20% (w/w) of the whole fruit weight, respectively [18,19], and are a good source of secondary products such as tannins, organic acid, polyphenol, and alkaloids [20][21][22]. Shaddock, like other citrus fruits, has a small edible portion and large amounts of waste materials such as peels and seeds, and peels contain considerable phenolic compounds [23]. At present, the polyphenols have shown significant inhibition to the growth of harmful algae. Therefore, these previous results indicate that the shaddock peel, pomegranate peel, and pomegranate seed could be used as an algicide.The objectives of this study are to identify the alle...

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