Towards Simazine Monitoring in Agro-Zootechnical Productions: A Yeast Cell Bioprobe for Real Samples Screening.

Gerardo Grasso,Giulia Cocco,Roberto Dragone,Ludovico Caracciolo,Chiara Frazzoli

doi:10.3390/bios8040112

Abstract

Simazine is an herbicide that is able to contaminate surface waters, ground waters, and milk/dairy products, thus posing concerns in both environmental health and food safety. A yeast-based bioprobe was utilized to detect simazine in spiked real samples of livestock drinking water and raw cow’s milk. Yeast aerobic respiration was taken as short-term toxicological endpoint. We carried out comparative measures of yeast oxygen consumption between simazine-spiked samples and blank samples. Percentage interference (%ρ) on yeast aerobic respiration was calculated through the comparison of aerobic respiration of simazine-exposed and non-exposed yeast cells. The method was optimized for raw cow’s milk samples by using boric acid as fungistatic agent in order to avoid cellular proliferation. Overall, the results have shown that simazine can be detected up to concentrations five times below the EU legal concentration limits for drinking water (0.02 ppb) and cow’s milk (2 ppb) (%ρ values of 18.53% and 20.43% respectively; %RSD ≤ 15%). Dose-effect relationships of simazine were assessed. The findings of the bioassays match reasonably well with known mechanisms of toxicity and intracellular detoxification in yeast. A correlation between fat content in milk samples and analytical performance of the bioprobe was established. Results suggest the involvement of a matrix effect, presumably due to lipid sequestration of simazine. The yeast-based bioprobe has proved to be sensitive and suitable for the detection of simazine in real samples in concentrations of interest.

Highlights

The chloro-s-triazines is an important family of pre-emergence herbicides extensively used for weed control in crop areas of e.g., corn, sorghum, sugarcane, orchards, and perennial crops, well as in non-crop areas
Even though simazine use as herbicide was banned in the European Union [2], it is still utilized in many countries, including the United States
During the 12 h O2 consumption monitoring, signal fluctuations registered from milk samples containing 0.16% w/v boric acid were less than 0.10 ppm

Summary

Introduction

The chloro-s-triazines is an important family of pre-emergence herbicides extensively used for weed control in crop areas of e.g., corn, sorghum, sugarcane, orchards, and perennial crops, well as in non-crop areas. Simazine (6-chloro-N,N 0 -diethyl-1,3,5-triazine-2,4-diylamine) is one of the most relevant members of chloro-s-triazines, as it is an herbicide used as a desiccant, defoliant and as algaecide for the aquatic weed control [1]. Even though simazine use as herbicide was banned in the European Union [2], it is still utilized in many countries, including the United States Simazine is moderately persistent in the environment [5], and due to its water solubility (6.2 mg/L). Simazine is the second most commonly detected pesticide in surface and ground waters in the United States, Europe, and Australia [1]. Since 2005, simazine is no more in production in Italy, but it is still present in Italian natural waters [6]

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Conclusion