Evaluating acute toxicity of methyl parathion application in constructed wetland mesocosms

Abstract Background Urban river pollution risks to environments and human health are emerging as a serious concern worldwide. With the aim to achieve the health of urban river ecosystem, numerous monitoring programs have been implemented to investigate the spectral characteristics of contamination. While due to the complexity of aquatic pollutants, the linkages between harmful effects and the spectral characteristics of contamination are still a major challenge for capturing main threats to urban aquatic environments. To establish these linkages, surface water (SW), sediment pore water (SDPW), and riparian soil pore water (SPW) were collected from five sites of the seriously polluted Qingshui Stream, China. The water-dissolved organic carbon (DOC), total nitrogen (TN), total phosphate (TP), fluorescence excitation–emission matrix, and specific ultraviolet absorbance were applied to analyze the spectral characteristics of urban river contamination. The Photobacterium phosphorem 502 was used to test the acute toxicity of the samples. Finally, the correlations between acute toxicity and concentrations of DOC, TN, TP, and the spectral characteristics were explored. Results The concentrations of DOC, TN, and TP in various samples amounted from 11.41 ± 2.31 to 3844.67 ± 87.80 mg/L, from 1.96 ± 0.06 to 906.23 ± 26.01 mg/L and from 0.06 ± 0.01 to 101.00 ± 8.29 mg/L, respectively. The florescence index (FI) amounted from 1.54 to 3.14, the biological index (BIX) were between 0.94 and 1.57. The distribution patterns of specific ultraviolet absorbance at 254 nm (SUVA254) showed that the highest aromaticity and hydrophobicity were found in SDPW and the lowest ones were in SW. All samples showed significantly inhibition on luminescent bacteria. Particularly, the highest acute toxicity was found in site 1 with an EC50 value of 6.023-fold dilution for the raw SDPW sample. In addition, the highest fluorescence intensity was also observed from SDPW of site 1. Conclusions Tryptophan-like and protein-like substances could be important DOC fractions contributing remarkably to the acute toxicity in the seriously polluted river. In addition, the significant reduction on acute toxicity was found with the treatment of surface water flow constructed wetland, revealing that constructed wetland could be an effective approach for toxicant degradation. These observations are useful for water treatments, and meaningful for urban sustainable development.

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Diel fluctuations of high level nitrate and dissolved organic carbon concentrations in constructed wetland mesocosms

Ecological Engineering ◽

10.1016/j.ecoleng.2019.04.027 ◽

2019 ◽

Vol 133 ◽

pp. 76-87 ◽

Cited By ~ 1

Author(s):

Tiffany L. Messer ◽

François Birgand ◽

Michael R. Burchell

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Constructed Wetland ◽

High Level ◽

Diel Fluctuations ◽

Carbon Concentrations ◽

Wetland Mesocosms

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TOXICIDADE AGUDA DO INSETICIDA PARATION METÍLICO E DO BIOPESTICIDA AZADIRACTINA DE FOLHAS DE NEEM (Azadirachta indica) PARA ALEVINO E JUVENIL DE PACU (Piaractus mesopotamicus)

Pesticidas Revista de Ecotoxicologia e Meio Ambiente ◽

10.5380/pes.v14i0.3127 ◽

2004 ◽

Vol 14 ◽

Cited By ~ 1

Author(s):

CLAUDINEI CRUZ ◽

JOAQUIM G. MACHADO-NETO ◽

MANOEL LIMA DE MENEZES

Keyword(s):

Body Weight ◽

Acute Toxicity ◽

Environmental Risk ◽

Azadirachta Indica ◽

Methyl Parathion ◽

Juvenile Fish ◽

Aquatic Environments ◽

Piaractus Mesopotamicus ◽

Neem Leaves

Os objetivos deste trabalho foram calcular a CL (I) 50-96h do inseticida organofosforado paration metílico e do biopesticida azadiractina para alevinos e juvenis de pacu ( P. mesopotamicus). Também pretendeu-se avaliar o efeito do peso corpóreo sobre a toxicidade aguda do paration metílico e do neem para o pacu, bem como classificar o risco ambiental do uso de paration metílico e do neem para o controle de parasitas e patógenos de pacu. Foram realizados dois experimentos, em condições laboratoriais, para a determinação da concentração letal (CL (I) 50-96h). A CL (I) 50-96h calculada do paration metílico foi de 3,97 mg/L para os alevinos e de 9,89 mg/L para os juvenis. Para a azadiractina foi de 1,20 mg/L para os alevinos e de 1,18 mg/L para os juvenis. As concentrações de 1,0 mg/L de paration metílico para os alevinos e de 7,5 mg/L para os juvenis e as de 0,29 e 0,59 mg/L de azadiractina não provocaram mortalidade nos animais expostos e podem ser utilizadas como referência em estudos de controle de parasitas em pacu . O paration metílico foi menos tóxico para os alevinos e para os juvenis de pacu do que a azadiractina, indicando a necessidade de cuidados com a utilização de extratos aquosos de neem no ambiente aquático. ACUTE TOXICITY OF THE INSECTICIDE METHYL PARATHION AND OF THE BIOPESTICIDE AZADIRACHTIN FROM NEEM LEAVES (Azadirachta indica) TO ALEVINE AND JUVENILE PACU (Piaractus mesopotamicus) Abstract The objectives of the present study were: to calculate the lethal concentration LC (I) 50-96 h of methyl parathion and of the biopesticide azadirachtin to alevine and juvenile pacu ( P. mesopotamicus). Also to determine the effect of body weight on acute toxicity of methyl parathion and of neem for pacu, as well as to classify the environmental risk of the methyl parathion and neem uses for the control of pacu parasites and pathogens. Two experiments were performed under laboratory conditions for the determination of the LC (I) 50-96 h. The LC (I) 50-96 h of methyl parathion was 3.97 mg/L for alevine and 9.89 mg/L for juvenile fish. The LC (I) 50-96 h of azadirachtin was 1.20 mg/L for alevine and 1.18 mg/L for juvenile pacu. Concentrations of 1.0 and 7.5 mg/L of methyl parathion and of 0.29 and 0.59 mg/L of azadirachtin for alevine and juvenile pacu, respectively, did not cause mortality in the exposed animals and can be used as references in studies on the control of parasites in pacu. Methyl parathion was less toxic to alevine and juvenile pacu than azadirachtin, indicating the need for careful utilization of aqueous neem extracts in aquatic environments.

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