Distribution of phthalic acid esters in agricultural plants and soil

ZORNIKOVA, G. , JAROSOVA, A. , HŘIVNA, L. : Distribution of phthalic acid esters in agricultural plants and soil. Acta univ. agric. et silvic. Mendel. Brun. , 2011, LIX, No. 3, pp. 233–238 The study observed the occurrence of di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) in the soil and agricultural crops (Triticum aestivum, Brassica napus, Zea mays) and their distribution to the individual parts. For the experiment were selected 4 locations in central Moravia. At two locations (L1, L2) winter wheat (Triticum aestivum) was grown, at the third location (L3) winter oilseed rape (Brassica napus), and at the fourth location (L4) fl int corn (Zea mays). The soil samples (n = 72) and whole plant samples (n = 78) were collected during the vegetation. The aboveground and underground parts of plants, ears, siliques and seeds were analyzed separately. The values of DBP in soil at all areas ranged from 0.28 to 1.59 mg.kg−1 of dry matter and DEHP < 0.03 to 0.73 mg.kg−1 of dry matter. The soil at the L4 site, which was the most fertilized with organic fertilizers, especially manure, was detected signifi cantly (P < 0.05) to show the highest values of both the PAEs (phthalic acid esters) observed (DBPL4 1.59 ± 0.07 mg.kg −1 of dry matter, DEHPL4 0.73 ± 0.18 mg.kg −1 of dry matter). Average concentrations measured in underground parts of monitored crops ranged from 1.68 to 14.26 mg.kg−1 of dry matter for DBP, and 0.12 to 10.34 mg.kg−1 of dry matter for DEHP. Values detected in aboveground parts were 0.03 to 8.84 mg.kg−1 of dry matter for DBP, and 0.25 to 4.59 mg.kg−1 of dry matter for DEHP. Average values of DBP in fi nal products ranged from 0.05 to 0.83 mg.kg−1 of dry matter, and < 0.06 to 0.98 mg.kg−1 of dry matter for DEHP. phthalic acid esters, di-n-butyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP) Phthalic acid esters (PAEs) have long been used as plasticizers of polymer materials. These materials gain fl exible features, improve adhesion and solubility. They are most o en added to paints, varnishes, adhesives, sealants, coatings, fl oor coverings, wire insulation, or dialysis equipment, and blood transfusion bags. In order to produce the above mentioned products, most used are the esters of di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP). In 2007, the EU produced about 10,000 tons of DBP and 341,000 tons of DEHP, while in the last decade the production has dropped by about one-third (ECHA, 2009). Phthalates are released to the environment during their production and processing of plasticizer, particularly through wastewater. However, a greater degree of contamination of the environment is caused by their release from the goods or landfi ll leachate. The contamination of agricultural soils can occur through fallout from the air, oil leakages from farm machinery or frequent fertilization with organic fertilizers (Vikelsoe et al., 2002; Cai et al., 2006). A plant receives nutrients, including toxic substances, particularly through the root system as well as above-ground green parts of plants. For some types of crops, a greater accumulation of phthalates in stems was demonstrated (Yin et al., 2003). Species specifi city in the sensitivity of crops to the income of phthalic acid esters is an important factor (Dueck et al., 2003; Yin et al., 2003; Kato et al., 1980). 234 G. Zornikova, A. Jarosova, L. Hřivna Incidence of di-n-butyl phthalate (DBP) and di-(2ethylhexyl) phthalate (DEHP) in agricultural crops and their distribution in various parts of plants were observed in this study. The emphasis was placed on the transport of phthalates in plant crops which were further processed for food production or from feeding livestock. During the growing period, plants and soil were collected from four locations in central Moravia. MATERIAL AND METHODS Investigations were carried out at 4 locations in central Moravia selected on the basis of preliminary analyses of phthalates in soil. At two locations (L1, L2) winter wheat (Triticum aestivum) was grown, at the third location (L3) winter oilseed rape (Brassica napus), and at the fourth location (L4) fl int corn (Zea mays). It the L1 and L2 locations in April, June and July (I–III. sampling) soil samples (n = 18) from arable layer by a probe rod and plant samples (n = 18) were collected. At the L3 site soil samples (n = 18) and plant samples (n = 24) were also collected in April, May, June and July (period I.–IV.). Samples of fl int corn plants (n = 18) and soil samples (n = 18) from the site of L4 were obtained in June, September and November (period I.–III.). The sampled plants were properly cleaned, aboveground and underground biomasses were separated and lyophilization was implemented. The aboveground and underground parts of plants, ears, siliques and seeds were analyzed separately. Lyophilized samples were extracted three times through a mixture of n-hexane:acetone (1:1). Solvent was evaporated on a rotary evaporator and dried with nitrogen from united extracts. For samples of winter oilseed rape, from the obtained extract lipid fraction was separated using gel permeation chromatography Bio Beads S-X3 column. As a mobile phase a mixture of dichloromethane:cyclohexane (1:1) was applied. For the purifi cation of samples, hydrated sulfuric acid was used. Sample purifi ed in this way was dissolved in 1ml of acetonitrile and analyzed by HPLC in harmony with protocols by Jarosova et al. (1999). Detection and quantifi cation was performed by HPLC analysis with a Cogent e-Column C18 (grain 5 μm, length 150 mm, mobile phase of acetonitrile:water 99:1) and UV detection at a wavelength of 224 nm. Chromatograms obtained were evaluated on a fi ve-point calibration curve in the so ware of Agilent Chemstation for LC and LC / MS systems. For statistical evaluation the so ware of Statistica 9.0 was used. The results were evaluated by Student’s distribution methods.