Novel Pesticide Extraction Method for River Water Samples

Researchers from the Harbin Institute of Technology, Harbin, China, have developed a simple method for the extraction of organochlorine pesticides (OCPs) from river water samples using magnetoliposomes as adsorbents and gas chromatography tandem mass spectrometry (GC–MS/MS) (1).

As an important form of pest control since the 1940s, OCPs were mass produced and widely applied to agriculture across the world. Their effectiveness in the fight against disease vectors such as mosquitoes to combat malaria and typhoid fever has been documented (2). However, as numerous studies identified the toxic effects OCPs have on aquatic organisms, their accumulation in the ecosystem, their negative effect on biodiversity, and potential threat to human health, a movement emerged to prohibit their use. Despite a ban beginning in the 1970s, developing nations continued to use the compounds because they were cost-effective and effective as a pest control substance (3–5).

As the world’s second largest pesticide manufacturer, China was estimated to have produced 203,000–381,000 metrics tons of technical-grade pesticides annually between 1985 and 1996 (6). Although today most OCPs have been banned, the legacy of those years can still be found within environments across China, and with numerous pollution pathways, aquatic environments are particularly at risk of OCP contamination. Continued research and monitoring of OCPs in these environments is key to China’s renewed commitment to repairing the damage to its environment, and several methods have been reported for the analysis of OCPs in environmental matrices including GC coupled to MS methods (1). However, it is difficult to detect OCPs in environmental water directly because most OCPs are lipophilic chemicals and are usually present at ultra-trace levels. Therefore, the inclusion of extraction and enrichment steps before GC–MS analysis is necessary.

Conventional sample preparation methods used for OCP analysis such as liquid–liquid extraction (LLE) are well-known to be laborious and time-consuming. Recently, solid-phase extraction (SPE) has also been used, but cumbersome sample loading issues continue to affect traditional SPE methods (7). As an alternative method, researchers developed a novel and fast method based on the use of magnetoliposomes as adsorbents to extract and enrich OCPs, analyzing surface water samples of the Songhua River, China, to test the method.

Researchers reported that the synthesized magnetoliposomes were successfully applied for the fast extraction and enrichment of OCPs. Total concentrations of OCPs at ten sampling sites were found in the range 0­–7.29 ng/L. Hexachlorobenzenes (HCBs) were the dominant pollutant found representing 50% of all OCPs identified, with significantly higher concentrations of the pollutant lindane in agricultural areas compared to urban areas.

References

1.     H. Wang et al., Sci. Total Environ.618, 70–79 (2018).

2.     D. Luo et al., Environ. Int.92–93, 276–283 (2016)

3.     A. Bajwa et al., Chemosphere152, 292–300 (2016).

4.     A.H.B Oliveira et al., Sci. Total Environ.542, 254–263 (2016).

5.     D. Wei et al., Environ. Int.33, 894–902 (2007).

6.     J. Huang et al., Farm pesticides, rice production, and human health. Research Report. Economy and Environment Program for Southeast Asia (2000).

7.     H. Chen et al., Environ. Sci. Pollut. Res.20, 8567–8578 (2013).