INVESTIGATION OF Pb AND Ni LEVELS IN SUNFLOWER PLANT AGRICULTURE TWO DIFFERENT PH ENVIRONMENTS

OZ Bu calismada Kirklareli Ilinde bulunan iki farkli pH ortamina sahip tarim arazilerinden toplanan toprak orneklerinde agir metallerin (Pb ve Ni) iliskisinin incelenmesi amaclanmistir. Kirklareli ve Kavakli ilcesindeki ciftlik arazisinden calisma pH degerleri farkli ve 3 farkli donemde (bitkinin olusumundan sonra 1. ve 6. hafta, hasat zamani) btki ornekleri alindi. Pb ve Ni metallerinin konsantrasyonunu belirlemek icin okuma islemi Alevli Atomik Absorpsiyon Spektrofotometresi (FAAS) ile gerceklestirildi. Birinci bolgedeki topraklardaki Pb ve Ni metal konsantrasyonlari 36.3-43.7 mg / kg ve 12.6-14.9 mg / kg, ikinci bolgede ise toprak konsantrasyonlari 11.7-17.1 mg / kg, 0.09-0.24 mg / kg, 3.12 idi. Sirasiyla -4.353 mg / kg, 7.89-11.2 mg / kg, 56.3-9.54 mg / kg. Birinci bolge bitki bilesenlerindeki Pb ve Ni metal konsantrasyonlari sirasiyla 1.93-12.1 mg / kg ve 0.56-11.8 mg / kg, ikinci bolge ise sirasiyla 6.92-14.8 mg / kg ve 0.58-9.37 mg / kg idi. Bagil standart sapmanin (RSD)% 10'dan az oldugu bulundu. Numunelerin analizinin RSD'si tatmin edici bir hassasiyete sahip oldugu belirlenmistir. Abstract In this study, in the soil samples collected from farmland with two different pH environments located in Kirklareli Province, heavy metals (Pb and Ni) were aimed to investigate the relationship. The working pH values are took in 3 different periods (after the formation of the plant, week of 1 and 6, harvest time) from the farm land in the town of Kirklareli and Kavakli. In order to determine the concentration of Pb and Ni metals, the reading process was performed by the Flame Atomic Absorption Spectrophotometer (FAAS). The concentrations of Pb and Ni metals in soils in the first region were 36.3-43.7 mg/kg and 12.6-14.9 mg/kg, in the second region soil concentrations were 11.7-17.1 mg/kg, 0.09-0.24 mg/kg, 3.12-4.353 mg/kg, 7.89-11.2 mg/kg, 56.3-9.54 mg/kg, respectively. The concentrations of Pb and Ni metals in first region plant components were 1.93-12.1 mg/kg, and 0.56-11.8 mg/kg, the second region was 6.92-14.8 mg/kg and 0.58-9.37 mg/kg, respectively. The relative standard deviation (RSD) was found to be less than 10%. The RSD of analysis of samples have satisfying precision.


INTRODUCTION
In the world, there has been a great progress in the industrial and industrial fields with the technology to meet the basic needs of the people [1][2][3]. As a result of this progression, it should not be ignored that pollution poses a serious problem to the environment, and that pollution, especially to the agricultural land, air layer and the water resources used for irrigation purposes, cause serious damage. In this context, there is a significant decrease or extinction of living species and basic food products. The most important environmental problem in the world is heavy metal pollution. Heavy metals are an important area for the most widely used and monitored pollutants due to their common uses [3][4][5][6][7][8][9].
Lead (Pb) is the metal that causes the most damage to our environment with human activities. Pb is one of the most important heavy metals emitted as a metal or organo-metallic compound into the atmosphere and creates ecological pollution due to its toxic properties [7][8][9][10][11][12][13].
It was revealed that the nickel (Ni) was a nutritional element needed for the growth and development of plants since 1987 [14,15]. The need for nickel in plants is necessary in the germination period of the seed. In addition, nickel is a metal part of urease enzyme and many hydrogenase enzymes, which is a catalase enzyme that converts urea to ammonium and carbon dioxide [14][15][16].
Helianthus annuus L. (sunflower) is one of the most important oil plants produced and used today. Sunflower oil is among the most preferred vegetable oils in terms of food quality [8,[17][18][19][20].
For this reason, sunflower cultivation is also very common in the world. One of the factors affecting the transition of the necessary nutrients to the plant in plant development is undoubtedly the pH of the soil. As shown by the tolerance of the specific pH range of each plant, the sunflower plant can maintain its growth within the pH range of 6.0-7.2 [1,21]. In addition to the upper or lower values of these limits, there is a decrease in plant growth, decline and decrease in product efficiency. In recent years, various breeding studies have been carried out to take control of weed in sunflower.
In this study, the sunflower (Helianthus annuus L.) grown or grown in two different pH environments in Kırklareli province, the possible residual contents of the soil and its components (root, leaf, stem and seed) grown in sunflower plants, possibly possible Pb and Ni metal levels are aimed to determine the relationship between.

Study Area
This study was carried out in the farmland and the farmland in the Kavaklı District, which is located 10 km west of the province and in the agricultural land connected to the Atatürk Soil Water and Agricultural Metrology Research Institute, 4 km west of the city of Kırklareli on the Thrace side of the Marmara Region.

Sample Collection
In this study, soil and sunflower-parts (root, stem, leaf, head and seed) samples which taken from TUBITAK-113Y529 project were used. These samples were two different pH values in Kırklareli Merkez (7.28) and Kavaklı (4.95). The periods in which the samples were taken and the plant components taken were shown in Table 1. Research Institute, in the soil of the trial agricultural land has a clay soil structure and a neutral pH.
As the second location, land information of Kavaklı agricultural land, in the soil structure is sand and has the property of aciditiy pH.

Sample Preparation
Samples collected from specified points were brought to the laboratory and the sunflower plant was washed with tap water, then 3 times with pure water and then dried at 40 °C in the oven. The dried plant samples were ground by a titanium-coated blender and prepared for weighing. Soil samples were also dried at room temperature and passed through a 450 mesh sieve.

Dissolution process in the microwave
For heavy metal analysis of the samples, CEM-MARS 6 brand microwave was used during the solubilization process. Optimization studies were conducted for the appropriate solubilization process. Power and temperature scans were performed for the most suitable dissolution for plant and soil samples ( Table 2 and Table 3). The fourth method was chosen as the most suitable solubilization method for the plants and the third method was chosen for the soil.   1  600  20  100  180  5  40  2  600  20  100  200  5  40  3  600  20  100  220  5  40 Samples of plant components for microwave solubilization were weighed in an analytical precision balance of 0.5 g and transferred to 75 mL of teflon flasks. 1 mL of 35% H2O2 (Merck) and 9 mL of 65% concentrated HNO3 (Merck) were added to the vessels and digested (Table 2 fourth method) in the microwave, respectively. The dissolved samples were then taken to the falcon tubes and centrifuged at 15 °C at 5000 rpm for 7 minutes. The decanted supernatant was evaporated in a water bath at 40-45 °C until 2-3 mL remained and was completed with ultrapure water to a final volume of 50 mL. Soluble samples were prepared for reading by FAAS.
Samples of soil components for microwave solubilization were weighed in an analytical precision balance of 0.5 g and transferred to teflon flasks. 1 mL of 35% H2O2 (Merck) and 9 mL of 65%  (Table   3 thirth method) in the microwave, respectively. As in the plant sample, the soil samples were prepared for reading with same metod by FAAS.
The same methods were made to blind samples and blind absorbance values were calculated by subtracting the actual values from the absorbance values.

Preparation of standard solutions and reagents
For standard solutions of metals, 1000 mg/L NIST standard stock solutions were used. The standards of the metals for Pb and Ni to be analyzed were prepared for the appropriate working range of 0.025-2 mg/kg. Standard solutions were prepared by dissolving with 1 M HNO3.
Agilent 240 AA Duo model flame atomic absorption spectrophotometer (FAAS) was used for metal analyzes. Device parameters for metal analysis were given in Table 4.

RESULTS
The heavy metal contents of samples, which sunflower plant and soil were collected of the samples taken from 3 different periods in two different pH environments in Kırklareli, were determined by FAAS. The obtained results were compared with the national and international quality control standard limit values such as Turkish Food Codex and WHO/FAO (World Health Organization/Food and Agriculture Organization) [19,22,23]. The heavy metal concentration  Table 5.   between 12.6-14.9 mg/kg and 5.63-9.54 mg/kg, while, plant parts were found between 0.56-11.8 mg / kg and 0.58-9.37 mg/kg, respectively.
As a result of metal analysis were investigated in contents of Pb and Ni. When soil and plant samples were compared according to European Union standard, Turkish Food Codex and WHO limit values, only, Pb concentrations were found to be above the limit values.