نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
High potential of the Weiss region for agricultural production and consequently, the impact of urban wastewater and agricultural activities, such as the use of various chemical fertilizers and pesticides, on the quality of soil, plants, and ultimately human health, reveals the need to do this research. This study aimed to investigate the effect of urban wastewater on the accumulation of lead and cadmium metals in fields under coriander plants. Random soil and plant samples were taken from an area irrigated with ground water and an area irrigated with wastewater. Soil and plant samples were digested after harvesting and heavy metals were measured using an atomic absorption spectrometer. The results showed that wastewater did not have a significant effect on the accumulation of lead and cadmium metals in soil. Although the concentrations of lead and cadmium in the soil irrigated with wastewater were higher than in the control soil (soil irrigated with ground water), the average concentrations of these metals in the soil irrigated with wastewater were lower than the international standard (FAO/WHO). Also, the concentration of cadmium in plants in soil irrigated with wastewater was lower than the standard, and the concentration of lead in plants was higher than the international standard. Since the average concentration of lead in coriander in the area irrigated with wastewater is higher than the standard, in order to prevent problems and protect the health of citizens, necessary planning should be implemented to reduce heavy metals in wastewater.
کلیدواژهها English
Today, Iran is facing a shortage of renewable water resources, and as one of the government's socio-economic policies, the optimal use of renewable resources has been emphasized, especially water recycling and reuse, groundwater recharge, and the reuse of treated human and industrial wastewater. Due to the fact that the Weis region has a high potential for agricultural production and subsequently the impact of urban sewage and agricultural activities, such as the use of fertilizers and various chemical poisons on the quality of soil, plants and ultimately human health, it reveals the need to conduct research. This research was conducted with the aim of investigating the effect of urban wastewater on the accumulation of lead and cadmium metals in fields cultivated with coriander.
In this study, 20 soil samples were collected from different fields under coriander cultivation in the Weiss region, 15 km north of Ahvaz, which had been irrigated with urban wastewater for consecutive years. Soil samples were transported to the laboratory and tested after preparation. A soil sample from fields irrigated with groundwater was taken as a control. To prepare plant samples, we collected 20 plant samples from the fields from which soil sampling was conducted and one plant sample from the fields irrigated with groundwater from which control soil samples were collected. They were washed with distilled water, dried at 70 degrees, powdered, and stored for analysis. Soil and plant samples after harvesting were digested with a combination of acids and heavy metals were measured using an atomic absorption device. Physical and chemical properties of the soil, including soil texture by hydrometric method (Gee and Bauder, 1986), soil pH and EC in 1:2 extract (Thomas, 1996), calcium carbonate equivalent percentage by neutralizing calcium carbonate with hydrochloric acid and titrating excess acid with sodium (Loeppert and Sparks, 1996), organic carbon percentage by wet oxidation method (Nelson and Summers, 1996), available lead and cadmium content by DTPA-TEA method (Lindsey and Norwell, 1978), and total lead and cadmium content of the soil with 4 M nitric acid (Esposito et al., 1982) were measured. Finally, the obtained data were analyzed with SPSS 20 software.
The results showed that wastewater had no significant effect on the accumulation of lead and cadmium metals in the soil. Although the concentration of lead and cadmium in the treated soil was higher than that of the control soil, the average concentration of these metals in the soil irrigated with wastewater was lower than the international standard (FAO/WHO). Also, the cadmium concentration of the plant in the treated soil was lower than the standard and the lead concentration of the plant was higher than the international standard. The results of soil pollution indicators showed that according to the international shale standard, the soil of the region is in the non-contaminated category.
In this study, the findings from comparing cadmium and lead elements in soil with international standards showed that the amount of elements was less than the standard limit. But they were higher than the control soil. Based on soil pollution indices including enrichment index, pollution factor and accumulation index, the soil of the region is in the category of non-polluted soil and the use of wastewater has not increased the lead and cadmium metals in the soil to the level of pollution. Comparing the amount of cadmium and lead in the plant with the standard values showed that the amount of cadmium was lower and the amount of lead was higher than the international standard. One of the reasons for the increase in these elements in the plant could be the use of chemical fertilizers, especially phosphate fertilizers. Since the amount of lead in the plant exceeded the standard, and given that there is a possibility that these elements enter the body through other contaminated foods, water, and air, which can overall increase the risk of endangering the health of the community, environmental considerations in this regard must be properly observed.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
The study was funded by the Yasouj University, Iran, and Grant No. 991041029.
Iran Haydari, Department of Soil Science, College of Agriculture, Yasouj University, Yasouj, Iran.
Data curation; Formal analysis; Investigation; Resources; Software; Funding acquisition; Validation; Writing - original draft.
Mohamad Rahmanian (corresponding author), Department of Soil Science, College of Agriculture, Yasouj University, Yasouj, Iran.
Methodology; Project administration; Resources; Supervision; Writing - review & editing.
Nafiseh Rangzan, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Khuzestan, Iran
Formal analysis; Validation; Writing - original draft.
All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.
No artificial intelligence tools were used in the article writing process.
The data that support the findings of this study are available from the corresponding author upon reasonable request.
The authors wish to express their deep thanks and gratitude to the Vice President of Yasouj University, who kindly participated in sponsoring this work.
The authors confirm that the study was conducted in accordance with ethical principles, and no data fabrication, falsification, plagiarism, or misconduct occurred.
The author declares no conflict of interest.
