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PRESENCE OF PHTHALATES,. BISPHENOL A, AND NONYLPHENOL IN PAPER. MILL WASTEWATERS IN SLOVENIA AND EFFICIENCY OF. AEROBIC AND ...
© by PSP Volume 20 – No 1. 2011

Fresenius Environmental Bulletin

PRESENCE OF PHTHALATES, BISPHENOL A, AND NONYLPHENOL IN PAPER MILL WASTEWATERS IN SLOVENIA AND EFFICIENCY OF AEROBIC AND COMBINED AEROBIC-ANAEROBIC BIOLOGICAL WASTEWATER TREATMENT PLANTS FOR THEIR REMOVAL Damjan Balabanič1,2 and Aleksandra Krivograd Klemenčič3* 1

Pulp and Paper Institute, Bogišićeva ulica 8, 1000 Ljubljana, Slovenia University of Nova Gorica, Vipavska 13, Rožna dolina, 5000 Nova Gorica, Slovenia 3 Department of Sanitary Engineering, Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, 1000 Ljubljana, Slovenia 2

1. INTRODUCTION

ABSTRACT Paper mills generate varieties of pollutants depending upon the type of the production process. Raw and biologically treated effluents from two paper mills with different production processes and different biological treatment plants were analysed by COD, BOD5, AOX as well as by phthalates, bisphenol A, and nonylphenol which are potential endocrine disrupting compounds. Removal efficiency of aerobic and combined aerobic/anaerobic wastewater treatment plants were studied for investigated compounds. The results indicated that dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di(2-ethylhexyl) phthalate, benzyl butyl phthalate, bisphenol A, and nonylphenol were present in raw and biologically treated paper mill effluents. The removal efficiencies of aerobic and combined aerobicanaerobic biological wastewater treatment plants were 87% and 87% for dimethyl phthalate, 79% and 91% for diethyl phthalate, 73% and 88% for dibutyl phthalate, 84% and 78% for di(2-ethylhexyl) phthalate, 86% and 76% for benzyl butyl phthalate, 74% and 79% for bisphenol A, and 71% and 81% for nonylphenol, respectively. Despite relative high removal efficiency of biological wastewater treatment plants for investigated compounds, the concentrations of nonylphenol in treated paper mill effluents exceeded limits of 0.3 µg/L according to Directive (2008/105/EC).

High water usage in pulp and paper industry, between 12.000 and 15.000 liters per ton of products, results in large amount of wastewater generation. Pulp and paper industry are significant contributors of pollutant discharges in the environment via wastewater [1]. The effluents from the paper mills can cause slime growth, thermal impact, colour problems, increase of the amount of toxic substances in the water, death of the zooplankton and fish, loss of aesthetic beauty in the environment and they can profoundly affect the terrestrial ecosystem [2]. Several authors have reported toxic effects on various fish species due to their exposure to paper mill effluents. Toxic pollutants were found in fishes and toxic effects were reported on fishes exposed to paper mill effluents such as liver damage, respiratory stress, mutagenicity, genotoxic and lethal effects [3-6]. Important pollutants in paper mill wastewaters are endocrine disrupting compounds (EDCs), which can have adverse effects on the living organism due their interference with the endocrine system [7]. One of the main reasons for concern is the possible effect of EDCs on human health. EDCs are suspected of causing abnormalities in sperm and increased hormone-related cancers in humans [8-11]. Other human health effects include increases in testicular and prostate cancer, cryptorchidism, hypospadias, and female breast cancer [8-13]. Some studies have also been published on the estrogen-like responses of EDCs in wildlife, such as birds, amphibians, reptiles and fish [14]. Chemicals known as human EDCs are phthalates, bisphenol-A (a chemical used in the manufacture of polycarbonate derived products and epoxy resins), some heavy metals (cadmium, lead, mercury), dioxins (by-products of paper bleaching), brominated flame retardants, PAHs (polyaromatic hydrocarbons), pesticides (e.g.

KEYWORDS: bisphenol A, industrial wastewaters, phthalates, nonylphenol

* Corresponding author

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pentachlorophenol, dieldrin, atrazine, chlordane), and alkylphenols [11, 15, 16]. Most of above listed chemicals are mutagenic and highly carcinogenic [11]. Some raw materials used for paper production contain phthalates; they are used also as softeners in additives, glues and printing inks. PAHs and heavy metals may also be found in printing inks, alkylphenols (nonylphenol) are constituents of widely used defoamers, cleaners, and emulsifiers while PCP (pentachlorophenol) is a major component of some biocides used in pulp and paper industry [17-19].

combined aerobic-anaerobic BWTP with retention time 30 hours for secondary treatment. Samples were collected in 5000 mL glass bottles prior and after both biological wastewater treatment plants. Altogether 120 samples were collected within four months in the year 2008 (August, September, October and November), of which 60 samples were collected at paper mill A and 60 at paper mill B. Sample bottles were refrigerated during transportation to the laboratory in order to prevent chemical changes.

Biological wastewater treatment plants (BWTPs) have been used to treat a wide variety of wastewaters. Numerous microorganisms, including bacteria, fungi and yeasts, predominantly aerobics, are known for their ability to degrade hydrocarbons to carbon dioxide, water and bacterial cells [20-22]. The biological treatment, particularly by the activated sludge process has been widely used for removal of organic compounds from paper mill wastewaters [1, 2]. The microbial composition of the activated sludge and its activity depend on the nature and availability of hydrocarbons, nutrient composition, and other environmental conditions such as temperature, pH and dissolved oxygen. The microbial degraders of organic compounds of contaminated areas are organotrophic species, which are able to use a huge number of natural and xenobiotic compounds as carbon sources [22].

2.2. COD, BOD5, AOX, and pH determination

Analyses of all effluent samples were performed in the laboratory immediately after collection according to the following standard methods: SIST ISO 6060:1996 (COD) [25], SIST 5815-1:2003 (BOD 5) [26], and SIST ISO 9562:2000 (AOX) [27]. pH was measured directly at the sampling sites according to SIST ISO 10523:1996 [28]. COD analyses were performed in three replicates; BOD5 and AOX analyses were performed in two replicates. COD was determined by dichromate method. 2.3. The procedure of the sample pre-treatment for gas chromatography-mass spectrometry (GC-MS) determination of phthalates, bisphenol A, and nonylphenol

For GC-MS determination of phthalates, bisphenol A, and nonylphenol all samples were filtered through 0.45 µm membrane filters and solid phase extracted (SPE) using Oasis HLB cartridges (200 mg/5 mL, flow rates 3-5 mL/ min). The SPE cartridges were conditioned with 3 mL of methanol (flow rates 10-20 mL/min) and equilibrated with 3 mL of deionised water (flow rates 10-20 mL/min). After sample extraction, the SPE cartridges were washed out to clean impurities with 3 mL of methanol/water (40/60) and eluted with 5 mL of methanol/methyl t-butyl ether (10/90) to collect analytes.

The pollution level of the effluents from the papermaking industry has been so far evaluated mainly by the cumulative parameters, such as chemical oxygen demand (COD), biochemical oxygen demand (BOD5), conductivity, total phosphorus, total nitrogen and adsorbable organic halogen compounds (AOX) [e.g. 23], however little is known about the types and concentrations of individual toxic compounds. Due to more and more stringent international environmental standards researchers are focused their attention on developing technologies for removal of pollutants from various industries such as pulp and paper, leather, and pharmaceutical [24].

2.4. GC-MS determination of phthalates, bisphenol A, and nonylphenol

For the determination of phthalates, bisphenol A, and nonylphenol an Agilent 7890 GC-MS system with an auto sampler was used. The injector was operated in splitless mode. Analytes were separated on a DB5-MS column (30 m x 0.25 mm ID x 0.25 µm) using a 1 mL/min helium flow and temperature program with initial temperature 50 ºC (4 min), heating rate 8 ºC/min and final temperature 270 ºC (5 min). An injection volume of 1 µL was used for all analyses. Phthalates, bisphenol A, and nonylphenol were identified by characteristic MS spectra while their concentrations were calculated from the calibration curves of standard solutions. All chemicals used were of standard and analytical quality.

The aim of our research was to determine the level of phthalates, bisphenol A, and nonylphenol in the paper mill effluents in Slovenia and to determine the efficiency of aerobic and combined aerobic-anaerobic BWTP for their removal from paper mill effluents. The results will be useful for further studies of pollution prevention. 2. MATERIALS AND METHODS 2.1. Sampling

Samples were collected from effluents of two paper mills: paper mill A (water consumption 286 m3/h, wastewater amount 277 m3/h) is manufacturing labelpapers and flexible packaging papers from fresh cellulose fibers and has on site aerobic BWTP with retention time 48 hours for secondary treatment; paper mill B (water consumption 287 m3/h, wastewater amount 273 m3/h) is manufacturing cartonboard from 100% recycled fibers and has on site

3. RESULTS AND DISCUSSION The aim of our research was chemical characterisation of typical papermaking effluents with the main intention to determine the levels of different phthalates, bisphe-

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in the papermaking process with more appropriate fiber bleaching agents, such as peroxide. pH in both paper mill effluents were at the time of measurement neutral or slightly alkaline, in the treated effluents pH values slightly decreased (see Table 1).

nol A, and nonylphenol in raw and biologically treated paper mill effluents and to determine the efficiency of two different BWTPs for their removal. The usual parameters, such as COD, BOD5, AOX, pH and seven potential endocrine disrupting compounds: dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di(2-ethylhexyl) phthalate, benzyl butyl phthalate, bisphenol A, and nonylphenol were determined in the investigated paper mill effluents.

The GC-MS analysis revealed that among seven potential endocrine disrupting compounds, all seven were confirmed in effluents from two paper mills with different production process in Slovenia. SPE proved to be an efficient method for preparation of water samples for GC-MS analysis, SPE is known as a very sensitive method for trace analyses of organic pollutants in different types of aqueous matrices. The ranges with standard deviations for all seven identified potential endocrine disrupters are presented in Table 1. Among identified compounds di(2-ethylhexyl) phthalate and nonylphenol are on the list of priority substances according to Directive (2008/105/EC) [32] and bisphenol A is identified as substance subject to review for possible identification as priority substance or priority hazardous substance. According to Directive (2008/105/EC) [32] the limit value for surface waters for di(2-ethylhexyl) phthalate is 1.3 µg/L and for nonylphenol 0.3 µg/L. Our results showed (see Table 1), that raw paper mill effluents from both paper mills exceeded the limit value for di(2ethylhexyl) phthalate and nonylphenol, however biologically treated effluents met the above mentioned standards for di(2-ethylhexyl) phthalate but not for nonylphenol. Average values for di(2-ethylhexyl) phthalate in recovered paper mill effluents were 0.21 µg/L for paper mill A and 0.38 µg/L for paper mill B. According to Bodzek et al. [33] di(2-ethylhexyl) phthalate content in tap water in Poland is