Dioxin, Dioxin–Like PCBs and Indicator PCBs in Some Medicinal Plants Irrigated with Wastewater in Ismailia, Egypt

Abstract

Wastewater is often leaden with various contaminants that may accumulate in soils and can under some conditions enter the agricultural food chain. Concentrations of PCDD/Fs, DL-PCBs and NDL-PCBs have been determined using GC/HRMS in three of the commonly used medicinal plant (henna, rosemary, and moghat) grown on raw wastewater. In the case of henna and rosemary plants, all wastewater irrigated samples showed higher content of the studied contaminants than freshwater irrigated samples, while moghat samples, whether irrigated with freshwater or wastewater, had more or less the same content of the studied contaminants. Concentrations in plant samples ranged between 0.00004 and 0.865 pg WHO TEQ/g wet w for PCDDs, and between 0.03 and 1.86 pg WHO TEQ/g wet w for the PCDFs. Levels of PCB TEQ ranged from 0.005 to 0.76 pg/g wet w. In descending order, rosemary, henna, and moghat had the highest concentrations of total TEQ (PCDD/Fs + DL-PCBs). The congeners pattern in henna and rosemary samples was generally characterized by the dominance of PCDFs with a significant contribution from the lower (mono- to tri-) PCDFs. In moghat samples the profile was dominated by PCDDs, with OCDD contributing 100% to PCDDs. PCBs contribution to the total TEQ was on average 25%, 7% and 2% in rosemary, moghat and henna respectively. For NDL-PCBs, the sum concentration of 17 PCBs congeners increased from 2.65 to 4.13 ng/kg wet w in henna, and from 4.64 to 7.16 ng/ kg wet w in rosemary due to the irrigation with wastewater. Congener PCB 28 was the main contributor (60%) to sum 6 indicators in all samples, followed by PCB 52 (18%) and PCB 101 (6%).

Key Words:

• dioxins
• freshwater
• henna
• irrigation
• moghat
• PCBs
• rosemary
• wastewater

ACKNOWLEDGEMENT

This study was supported and the analytical part was conducted by Interuniversity Consortium of Chemistry for the Environment (INCA), Italy. Special thanks to Professor P. Tundo, and Dr. S. Raccanilli. Thanks are also due to Professor E. Qouraish from the Horticulture Department, Faculty of Agriculture, Suez Canal University, Ismailia, Egypt, for supplying medicinal plant samples.

Notes

∗Numbers with asterisk are the PCBs IUPAC no.

∗Six indicator PCBs: CB 28, 52, 101, 153, 138 and 180.