نوع مقاله : مقاله پژوهشی
نویسندگان
بخش تحقیقات خاک و آب، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان اصفهان، سازمان تحقیقات، آموزش و ترویج کشاورزی، اصفهان، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
ABSTRACT: Important environmental and health problems can be caused by heavy metals. Contamination of rice with cadmium is a serious risk for the quality and safety of this product. The objective of this study was to investigate the possibility of soil and rice grain contamination of some paddy fields of Isfahan Provence with heavy metals. A number of 105 soil samples were collected from 6 rice growing areas and the concentration of zinc, copper, iron, cadmium, and lead was measured. Contamination factor (CF) was used to determine soil contamination with heavy metals. Cadmium concentration was measured in the root, stem and grain of rice. The indices of hazard coefficient (HQ), bioaccumulation factor (BAF), and translocation factor (TF) of cadmium were calculated. The concentration of copper, zinc, and lead in the studied stations was lower than the permissible limit provided by the Iranian Environmental Organization for agricultural soils while the concentration of cadmium was higher than the permissible limit in about 21% of the studied samples. The trend of CF-Cd>CF-Fe>CF-Pb>CF-Cu>CF-Zn was observed. The rice grain cadmium concentration was lower than the national standard number 12968 in 36.4% of the samples. The value of HQ for adults and children was less than the permissible limit (HQ=1) in 54.5% and 18.2% of the studied samples, respectively. The average BAF was calculated as 0.03. According to the results, cadmium does not accumulate in the rice grain, but, it can threaten the health of both groups of adults and especially children in the near future.
کلیدواژهها [English]
EXTENDED ABSTRACT
Important environmental and health problems can be caused by heavy metals Heavy metals cannot be broken down into less harmful compounds due to chemical and biological processes. Therefore, they accumulate in soil and plants. Human health is directly affected by consuming crops grown in contaminated soils. Contamination of rice with cadmium is a serious risk for the quality and safety of this product.
The objective of this study was to investigate the possibility of soil and rice grain contamination of some paddy fields of Isfahan Provence with heavy metals.
A number of 105 soil samples were collected from 6 rice growing areas and the concentration of zinc, copper, iron, cadmium, and lead were measured in the samples. Contamination factor (CF) was used to determine soil contamination with heavy metals. Cadmium concentration was measured in the root, stem and grain of rice. Estimated daily intake (EDI) and reference value of cadmium were used to calculate the non-cancerous hazard coefficient of cadmium (HQ). The indices of bioaccumulation factor (BAF), and translocation factor (TF) of cadmium were calculated.
The concentration of copper, zinc, and lead in the studied stations was lower than the permissible limit provided by the Iranian Environmental Organization for agricultural soils while the concentration of cadmium was higher than the permissible limit in about 21% of the studied samples. The lowest lead contamination factor (CF-Pb) with a value of 0.32 was related to Qaleh Qasim station and the highest CF-Pb (2.15) was related to Jozdan station. The highest amount of CF-Cd was obtained in Jozdan station (1.75) and the lowest amount (0.96) was obtained in Chamgardan station. The trend of CF was observed as CF-Cd>CF-Fe>CF-Pb>CF-Cu>CF-Zn. The results showed that 11.4% of the CF-Cd values were in the low pollution class and 88.6% were in the medium pollution class. The amount of enrichment factor (EF) for heavy metals was obtained in the following order: cadmium > copper = iron > lead > zinc. The highest value of the enrichment factor for Cd was equal to 1.34 and the lowest value for Zn was equal to 1.02. The lowest amount of cadmium in rice grain was 0.24 mg kg-1 and the highest amount was 0.29 mg kg-1. The amount of the rice grain cadmium was lower than the national standard number 12968 in 36.4% of the samples. The amount estimated daily intake of cadmium through rice consumption (EDI) for adults ranged from 0.013 to 0.159 mg/kg/day, while for children it was in the range of 0.037 to 0.464 mg/kg/day. The value HQ for adults and children was less than the permissible limit of health index (HQ=1) in 54.5% and 18.2% of the studied samples, respectively. The lowest amount of HQ was related to the adults group (0.25) and the highest amount was 7.73 related to the children group. The amount of bioaccumulation factor of cadmium for rice grain was in the range of 0.011 to 0.053 in the stations investigated in this research. The highest value of BAF was related to Jozdan station. Comparing the amount of cadmium between different parts of the plant showed that the highest concentration of cadmium with an average of 1.85 mg kg-1 observed in the root. The amount of cadmium in the rice stem also varied from 0.09 (Chamgardan) to 0.32 (Jozdan) mg kg-1 between the studied stations. The values of translocation factor from stem to grain were higher than the values of TF from root to stem, although the values of bioaccumulation factor indicated no accumulation of cadmium in rice grains.
According to the results, rice grains consumption from some of the stations under study may threaten the health of both groups of adults and especially children in the near future. Therefore, in order to maintain food quality and safety, accurate management should be done. Also, it seems necessary to conduct such research in a planned and continuous manner.
Hamid Reza Rahmani conceived of the presented idea, developed the theory and carried out all stage of the experiment. Zahra Khanmohammadi carried out the statistical analysis, calculated the pollution indices and wrote the manuscript. All authors have read and agreed to the published version of the manuscript
Data is available on request from the authors.
The authors would like to thank the Rice Research Institute of Iran and Isfahan Agricultural and Natural Resources Research and Training Center for support of the present study.
The study was approved by the Ethics Committee of the Rice Research Institute of Iran (Ethical code: 2-38-04-88039). The authors avoided data fabrication, falsification, plagiarism, and misconduct.
The author declares no conflict of interest.