MGBECHI CLETUS E.

Department of Science Laboratory Technology, School of Applied Sciences, Federal Polytechnic, Oko. Tel: 08038964699, Email: cletus.ekene@yahoo.com

ABSTRACT

Tricyclazole is melanin biosynthesis inhibitors. Because of the increase in people’s attention to food safety, monitoring the residue of pesticide in rice is becoming more and more important. Commercial and home processing techniques have been used to transform paddy rice into rice products for human or animal consumption, which may reduce the pesticide content in rice. The degradation of tricyclazole during different stages of commercial and home processing and storage was assessed in this paper. Many researches studying the occurrence and distribution of pesticide during rice cropping and processing have been reported. Rice samples were extracted with acetonitrile, the extracts were enriched and then residues were analyzed by the analytical methods 6 (15), 5934 – 5941, 2014 (colorimetric sensor method). The dissipation dynamics of tricyclazole in rice plant, soil and paddy water fitted the first–order kinetic equations. Under optimal conditions, the linear range of the method was 1.0 x 100 µM. The limit of the detection was 1.8 x 10^-7M. The feasibility of this method has been demonstrated by the selective and sensitive measurement of tricyclazole in rice samples with good recoveries and relative standard deviation (RSD) > 20%.

Degradation dynamic equations of tricyclazole in the raw rice and polished rice were based on the first-order reaction dynamic equations. The results provide information regarding the fate of tricyclazole in the rice food chain, while it provides a theoretical basis for systematic evaluation of the potential residual risk of tricyclazole.

Keywords: Fungicide, Biochemical, Dietary, Rice, Tricyclazole.

INTRODUCTION

Improving knowledge on the dietary risk of pesticides is one of the major challenges to public health, especially for a vulnerable population. Pesticides are used to keep crops healthy and prevent them from being destroyed by disease and infestation.

Tricyclazole belong to melanin biosynthesis inhibitors, which are novel systemic triazole fungicide used widely in the Agricultural industry with wide spectrum of actions against fungal pathogens.^8-9 This  pesticides offers the benefits of protection, treatment and absorption and can prevent the growth and reproduction of fungi by interfering with ergosterol biosynthesis and inhibiting steroid demethylation.^2-3 It is widely used to control fungal disease, such as rice blast, grey mould, anthracnose and powdery mildew on fruits, cereals, vegetables and other field crops.^5-6 This fungicides is usually sprayed twice to control rice-blast on rice^7. Like other pesticides, it is difficult to prevent the release of tricyclazole into the surrounding environment after application, which might be harmful to human health.

In the previous literature, a number of studies on the residual behaviour of tricyclazole in rice, wheat, banana, grape, and pomegranate have been reported.^10-11 However, there has been no systemic study conducted on biochemical effects, residues distribution and dietary risk of tricyclazole in rice field. The maximum residue limits (MRLs) of tricyclazole in rice have not been formulated in Nigeria. The potential risks to the environment and human health has aroused much public concern. Therefore, it is significant to investigate and examine dietary exposure of tricyclazole in rice based on supervised field trial data and relevant toxicological parameters. The scientific data will offer guidance for the establishment of suitable MRLs of tricyclazole in rice and safe application in the field ecosystem for Nigeria.

MATERIALS AND METHOD

SAMPLE COLLECTION

The Rice samples were collected from Omor, Ayamelum L.G.A Anambra State, Nigeria.

The samples were extracted with acetonitrile, and then cleaned up by primary/secondary amine.

The extracts were enriched, and then residues were analyzed by a colorimetric sensor method. 5-sulfo anthranilic acid dithiocarbamate functionalized silver nanoparticles as a colorimetric probe for the simple and selective detection of tricyclazole fungicide in rice.

MATERIALS / METHOD

A sensitive and selective colorimetric sensor for the detection of tricyclazole fungicide was proposed. The characteristics surface Plasmon resonance (SPR) peak of 5-sulfo anthranilic acid dithiocarbomate functionalized silver nanoparticles (SAADTC-Ag NPs) at 400nm was drastically reduced by the addition of tricyclazole fungicides, and yielding a new SPR peak at 550nm, which can be observed by the discernible color change of the solution from yellow to pink. This detection mechanism was based on the tricyclazole-induced aggregation of the SAADTC – Ag NPs via election donor–acceptor interactions. other pesticides such as hexaconazole, propiconazole, tebuconazole and difenoconazole, do not interfere with the sensing of tricyclazole.

RESULT

Under optimal conditions, the linear range of the method was 1.0 – 100 UM. The limit of detection was 1.8×10^-7 M. The feasibility of this method has been demonstrated by the selective and sensitive measurement of tricyclazole in rice samples with good recoveries and a relative standard deviation (RSD) < 2%.

This distinct and rapid colorimetric response enables us to readily probe tricyclazole in food samples without more analytical technical demand.

DISCUSSION

These result provides information regarding the fate of tricyclazole in the rice food chain, while it provides a theoretical basis for systematic evaluation of the potential residual risk of tricyclazole. The dietary risks, assessed as hazard quotients, were far below 100%. The results showed that tricyclazole pesticides applied to rice crops were comparably unsafe for the consumer.

CONCLUSIONS

The colorimetric sensor method used provides full considerations of the rice consumed within a day for the estimation of the total exposure.

However, short-term exposure results are difficult to compare with the colorimetric sensor-methodology.

Further investigations of the exposure of tricyclazole in rice under field application are recommended before final conclusions on the dietary consumer risk can be drawn.

RECOMMENDATION

The result could be utilized for the assessment of the environmental risk associated with the use of tricyclazole in rice cultivation and the determination of potential mitigation measures for minimizing the risk for contamination of neighboring natural water resources. Further investigations on chronic and acute cumulative risks arising from tricyclazole are in the future to improve the assessment of dietary risk for consumers exposed to pesticides residues.

ACKNOWLEDGEMENT

The author would like to thank all the contributors  for their significant collaborations.

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