Fatma Beduk

Levels of Organochlorine Pesticides and Heavy Metals in Surface Waters of Konya Closed Basin, Turkey

The concentrations of organochlorine pesticides (OCPs), including α-, β-, γ-, and δ-hexachlorocyclohexane (HCH), heptachlor, heptachlor epoxide, dieldrin, aldrin, endrin, endrin aldehyde, endrin ketone, endosulfan I, endosulfan II, endosulfan sulfate, p,p′-DDE, p,p′-DDD, p,p′-DDT, methoxychlor, chlordane I, chlordane II, and heavy metals, such as As, Cr, Cu, Fe, Mn, and Ni in surface water samples from the Konya closed basin were determined to evaluate the level of contamination. Among all HCH isomers, β-HCH is the main isomer with a concentration range of 0.015–0.065 μg/L. DDE, DDD, and DDT were almost determined in all samples, in which DDE isomer had the highest concentration ranged from not detected to 0.037 μg/L. In all studied OCPs, aldrin showed the highest concentration at 0.220 μg/L. The concentrations of heavy metals in water samples were observed with order: Mn < Cu < Ni < As < Cr < Fe. In some samples, As, Fe, and Cr concentrations exceeded the drinking water quality recommended by EU, US EPA, WHO, and Turkish Regulation, while Cu, Ni, and Mn concentrations are below the guideline values. The levels of both OCPs and heavy metals were also compared with other previously published data.

Accumulation of Micropollutants in Aqueous Media and Sediment, A Risk Assessment for Konya Main Drainage Channel, Turkey

Human activities increase types and numbers of synthetic pollutants and their byproducts in the course of time. Synthetic Organic Chemicals (SOCs), so called micropollutants, present in very low concentrations in aquatic ecosystem, but likely accumulate in animal and human tissues and cells because of fat solubility. These persistent micropollutants have toxic effects in very low concentrations and resistant to biodegradation. SOCs can be adsorbed to sediments in surface water sources, so sediments have an important role in the accumulation of water contaminants. In the course of time, sediments become source of new contamination for aqueous media.

Analysis of diclofenac in water samples using in situ derivatization-vortex-assisted liquid-liquid microextraction with gas chromatography-mass spectrometry

Abstract A novel micro-extraction technique for a rapid and sensitive analysis of diclofenac (DCF) in water samples has been developed. DCF was derivatized and extracted simultaneously using vortex-assisted liquid-liquid micro-extraction (VALLME) prior to gas chromatography with mass spectrometry detection. The effects of extraction solvent volume, extraction and derivatization time and ionic strength of the sample were studied using 23 factorial experimental design. The optimum extraction conditions were as follows: 200 μL of chloroform, 25 μL of N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) derivatization reagent, vortex extraction and derivatization time 5 min at 3000 rpm. The extraction recovery for different fortification levels was 98 %. Also, the proposed micro-extraction method exhibited results comparable with the solid phase extraction of real water samples. The proposed one-step VALLME and derivatization method is simpler and faster than the conventional extraction and derivatization methods used for the determination of DCF in real water samples.

Acute Toxicity of Organophosphorus Pesticides and Their Degredation By-Products to Daphnia Magna, Lepidium Sativum and Vibrio Fischeri

Organophosphorus pesticides (OPPs) attained the growing importance in pests control because of their rapid decomposition and less likely accumulation in environment. They are still of great concern however, for water sources contamination because of their high solubility in water and excessive usage. Their usage amounts were elevated after they were introduced as replacements for the highly persistent organochlorine pesticides. They are classified into two main groups, organophosphates (P=O) and organothiophosphates (P=S) depending on whether oxygen or sulphur forms a double bond with the central phosphorous atom. They were found in environment with enough frequency (Ballesteros and Parrado, 2004) to constitute an ecotoxicological risk. Their concentration in water sources (Barcelo et al., 1990; Konstantinou et al., 2006), in air (Tuduri et al., 2006) and food (Bai et al., 2006; Darko and Akoto, 2008) can vary between a few ppb to ppm levels. The presence of these pesticides can directly affect the health of aquatic and terresterial organisms and may present a threat to humans through contamination of drinking water supplies. OPPs always pose acute toxicity but not chronic toxicity on organisms because of their quick degradation (Ye et al., 2010). OPPs are known to cause inhibition of acetylcholinesterase (AChE) in target tissues which leads to accumulation of acetylcholine. According to its key physiological role in nerve transmission, AChE is the target of various insecticides. AChE is an enzyme vital for normal nerve function and AChE inhibition leads to over stimulation of the central and peripheral nervous systems, resulting in neurotoxic effects in organisms. OPPs also produce oxidative stress in different tissues (Possamai et al., 2007) and shows genotoxic (Bolognesi, 2003; Cakir and Sarikaya, 2005, Arredondo et al., 2008) and immunotoxic (Yeh, et al., 2005; Day et al., 1995) effects. The majority of OPPs give rise to only slight inhibition of AChE by themselves, unless they undergo oxidative activation. This process involves the substitution of the sulfur atom in the P=S bond of the organophosphate pesticide with an oxygen atom resulting with formation of oxon derivatives (OPPs-oxons) (Fig. 1). This substitution is a result of advanced oxidation processes such as O3, O3/UV, H2O2/UV, fenton, photo-fenton, TiO2/UV, etc. in water treatment and natural oxidation processes such as UV radiation and microbial degradation. Combined oxidation systems decreases toxicity effects of by-products via enhancing mineralization. Kim et al. (2006) used Vibrio fischeri and