Integrated management of pesticides in an intensive agricultural area: a case study in Altinova, Turkey

A combined approach for the estimation of groundwater leaching potential and environmental impacts of pesticides for agricultural lands

Pesticide pollution can degrade the quality of land, water, and air, and imposes risks on people, flora and fauna. Pesticides are frequently chosen based on their agricultural effectiveness and cost, rather than their potential environmental impacts. The aim of this study is to present a combined approach to estimate the leaching potential and environmental impacts of pesticides for agricultural lands. The pilot study area (PSA) is the agricultural plain of the Lower Aksu Stream Basin in Antalya - Turkey. The groundwater of the agricultural plain contributes to around half of the flow rate of the stream. The first phase of the combined approach involved pesticide monitoring to screen the target pesticides, the second phase involved evaluating the physicochemical properties of the target pesticides and estimating their leaching potential using several indices, and the third phase involved environmental impact analysis of the target pesticides using the Environmental Impact Quotient (EIQ) risk indicator. Additionally, Principal Component Analysis was conducted to examine the correlations between physicochemical parameters of pesticides and the leaching potential index results. By the application of the combined approach, 45 target pesticides were identified for the PSA and the indices were consistent to estimate similar leaching potentials for the same pesticides. Moreover, the computed EIQ-Field Use Rates provided valuable information to rank target pesticides according to their environmental impacts on consumer, farmworker and ecology. The applied methodology provided a practical approach to select pesticides with the least leaching potential and environmental impacts to protect water quality and ecosystem health.

Evaluation of alternations in DNA methylation of CYP3A4 gene upstream regulatory elements in gastric cancer and in response to Diazinon treatment

BACKGROUND

Little is known about cytochrome P450 3A4 (CYP3A4) DNA methylation and transcription alterations in gastric cancer.

OBJECTIVE

In this paper, we initially aimed to address the effect of diazinon pesticide on DNA methylation and transcription changes of the CYP3A4 gene in a human gastric cell line. In the next step, we studied the methylation differences of CpG sites within the upstream regulatory regions of the CYP3A4 gene among human gastric cancerous and healthy tissues.

METHODS

For the in vitro assay, the methylation changes of the C/EBP response element and transcript level of the CYP3A4 gene were studied following treatment of the AGS cell line with various concentrations of diazinon pesticide. In the next phase, the methylation percentages of 24 CpG sites within or around the upstream regulatory elements including near promoter, C/EBP binding site, XREM, and CLEM4 in 11 specimens of human gastric cancer tissue were compared to their adjacent healthy tissues.

RESULTS

Treatment with 10 µM Diazinon significantly increased the CYP3A4 gene transcription by approximately 27-fold, which was correlated with the hypermethylation of 3 CpGs in C/EBP binding sites including -5998, -5731 and -5725 (p<0.001 for all comparisons). Results of bisulfite sequencing revealed that the CpG sites which are located in -1521 (p=0.003), -1569 (p=0.027), -10813 (p=0.003), -10851 (p=0.001) and -10895 (p=0.0) bp from transcription start site, were significantly hypermethylated in cancerous tissues comparing to their healthy cohort.

CONCLUSION

Hypermethylation of CLEM4 and a region near the core promoter may have a significant association with gastric cancer incidence.