بررسی غلظت نیترات و فسفات در برخی گیاهان حاشیه رودخانه کال شور سبزوار

Investigation of nitrate and phosphate concentrations in some plants
along the Kal-e-Shor river in Sabzevar

Document Type: Research Paper
Authors
Ali DolatabadiGhasem Zolfaghari, Nasrin Osmani
 Graduate of Environmental Science and Engineering. Department of Environmental Science and Engineering, Hakim Sabzevari University
Associate Professor of Environmental Science and Engineering, Department of Environmental Science and Engineering, Hakim Sabzevari University
 Graduate of Environmental Science and Engineering-Environmental Pollution, Department of Environmental Science and Engineering, Hakim Sabzevari University
Email of the corresponding author: g.zolfaghari@hsu.ac.ir


Abstract

The growing population of the world, along with the expansion of agricultural and industrial activities to provide food on the one hand and successive droughts in recent years on the other, has led to the availability of fresh surface and groundwater resources in most countries in the arid zone. Reach the peak of its exploitation and consequently put too much pressure on water resources. These conditions have been prevalent in Iran for a long time. On the other hand, the development of urbanization and industrialization has led to the production of a huge volume of wastewater, the main problem in this field is how to dispose of wastewater, so that it did not lead to environmental and health risks. In this regard, one of the best methods of wastewater disposal is its use in agriculture, this requires special management that while using it optimally, does not have environmental and health risks to soil, plants and surface and groundwater resources. One of the main solutions to deal with the water crisis is the use of water chain in proportion to changing its quality in various sectors of consumption. Another solution is the optimal use of existing conventional and non-conventional water and the use of efficient and high-efficiency irrigation systems. ا Since wastewater is considered as fresh but polluted water and its treatment cost is much lower than other methods of water supply, wastewater reuse is proposed to compensate for the lack of some water needs. In addition, municipal effluents are rarely affected by drought. Therefore, reuse of effluent can be a reliable source for use in dry and low rainy years.
The use of low quality water, including municipal wastewater, for agricultural production in arid and semi-arid regions of the world, including Iran, is increasing. Pollution caused by such waters, including nitrate and phosphate, accumulates in agricultural products and causes various diseases when it enters the human body. Methemoglobin (a disease of children) caused by the entry of nitrate into the human body and osteoporosis caused by the entry of phosphate. The general purpose of this study is to investigate the concentration of nitrate and phosphate in some plants along the Kal-e-Shor river in Sabzevar. The study population in this study is some crops and non-crops in the lands of Dolatabad and Aliabad regions that are irrigated using the water of Kalshur river. Due to the diversity of the crop in the region, two agronomic species (wheat and pistachio) and two non-agronomic species (straw and turmeric) have been selected for the study, which have been collected in three samples and examined for nitrate and phosphate concentrations. According to the results, the phosphate concentration in the green of the plants was as follows: Wheat leaf irrigated with effluent> Control wheat leaf> Kalshour turmeric leaf> Irrigated pistachio leaf> Control turmeric leaf> Kalshour straw leaf> Control straw leaf> Control pistachio leaf The greenery of the wheat field of the farm has the highest concentration of phosphate and the greenery of turmeric has the lowest concentration of phosphate. Nitrate concentration in greenery of plants was as follows: Wheat leaf irrigated with effluent> Wheat leaf control> Kalshour turmeric leaf> Pistachio leaf irrigated with effluent> Control turmeric leaf> Kalshour straw leaf> Control straw leaf> Control pistachio leaf, which Wheat leaves irrigated with effluent had the highest concentration of nitrate and pistachios of control fields (irrigated with well water) had the lowest concentration of nitrate. The higher phosphate concentration in the experimental farms compared to the control farms was due to the use of chemical fertilizers in the fields and poor field management. Nitrate concentration in the greenery of plants irrigated with wastewater (experimental farms) was higher than the greenery of control plants, which is due to the presence of nitrate in the effluent or poor farm management.
According to the results, the concentration of phosphate in the effluent of the study area is 0.610 mg/l, while the standard concentration of phosphate in the effluent for discharge to surface waters by the Environmental Protection Organization is 6 mg/l. The concentration of phosphate in the effluent is less than the allowable limit with a probability of 99%.
The concentration of nitrate in the effluent is 9.266 mg/l and the standard limit announced by FAO for irrigation is 5 mg/l and for discharge to surface water is 50 mg/l.
The concentration of nitrate in the effluent for irrigation is 95% higher than the standard, but for entering surface water is less than the allowable limit, so the concentration of nitrate for irrigation should be monitored.
Higher phosphate concentration in the leaves of experimental farms compared to control farms is due to the use of chemical fertilizers in farm management.
Nitrate concentration in the leaves of experimental field plants is higher due to the presence of nitrate in the effluent or poor field management.
There was no significant difference between the mean concentrations of nitrate and phosphate in wheat, straw and turmeric plants of Kalshour and control fields. The average concentration of nitrate in wheat leaves irrigated with effluent is 13.24 and in control wheat is 12.76. Also, the permissible concentration of nitrate in wheat (maximum concentration of nitrate in wheat) according to EU standards is 50 mg/kg, which indicates the measured values. Nitrate content in wheat irrigated with effluent is higher than allowed. The average concentration of nitrate and phosphate in the pistachio plant irrigated with effluent is higher than the pistachio plant in the control fields, this is probably due to the use of more fertilizer in the experimental pistachio fields.
Keywords
"Municipal wastewater effluent", "Nitrate in vegetable greenery", "Phosphate in vegetable greenery", "Water quality"