Adile Sari

The increasing use of pesticides in recent years is considered a threat to the environment and health. The current study intended to assess the potential phytotoxic impacts of tau-fluvalinate, a pyrethroid pesticide, on Lactuca sativa (Asteraceae) using germination and seedling development endpoints. For this purpose, germination percentage, relative seed germination, relative root growth, and germination index were determined for L. sativa seeds exposed to five different concentrations of tau-fluvalinate (12, 24, 48, 96, and 192 mg/L) for 48 h. Statistically significant differences were observed among the tested concentrations in terms of germination percentage, root and shoot length, relative seed germination, relative root growth, and germination index (p < 0.0001). Based on the calculated germination indices, the concentration of 12 mg/L was classified as non-phytotoxic but moderately inhibitory, 24 mg/L as moderately phytotoxic, and 48, 96, and 192 mg/L as highly phytotoxic. These findings indicate that tau-fluvalinate may pose environmental risks due to its acute toxic, sublethal, and phytotoxic effects, particularly at high concentrations. Furthermore, the results confirm that L. sativa is a sensitive and reliable bioindicator for assessing the phytotoxicity of synthetic pyrethroids.

As pesticides negatively affect non-target organisms, their excessive and indiscriminate use poses a threat to the environment and aquatic ecosystems. In this study, it was aimed to examine the lethal and sublethal effects of tau-fluvalinate, a pyrethroid pesticide, on the non-target organism Chironomus riparius. For this aim, acute toxicity of tau-fluvalinate was evaluated through a 96-h mortality test, and changes in the locomotor activity of C. riparius were examined after 72- and 144-h exposures to different sublethal concentrations. Mortality tests indicated that both concentration (F9, 240 = 133,80; P<0.0001; ηp2 = 0.83) and exposure duration (F3, 240 = 18,93; P<0.0001; ηp2 = 0.19) had statistically significant effects on mortality. In locomotor activity tests conducted at sublethal concentrations (2.75, 5.5, 11, and 22 µg/L) selected based on the calculated 96-h median lethal concentration (44.53 µg/L), concentration (F4, 60 = 236,7; P<0.0001; ηp2 = 0.94), exposure duration (F1, 60 = 35,48; P<0.0001; ηp2 = 0.37) and their interaction (F4, 60 = 3,629; P = 0.0103; ηp2 = 0.19) were found to have statistically significant effects on locomotor activity. As the first study to evaluate the effects of tau-fluvalinate on the non-target organism C. riparius, our findings demonstrate that tau-fluvalinate poses a considerable risk to C. riparius populations, largely due to its environmental persistence, and that its prolonged presence in aquatic ecosystems constitutes an environmental hazard.

This study aimed to examine the pollution level in the central part of the Büyük Menderes River (in both the main tributary and Çürüksu stream) in Denizli (Turkey) using water physicochemical parameters and biomarker responses in Chironomus riparius (Diptera: Chironomidae). In physicochemical parameter evaluations, Sığma, Korucuk, and Güzelköy stations were determined to have higher mean temperature, pH, salinity, conductivity, and total dissolved solids (TDS) values and lower dissolved oxygen (dO₂) and saturated oxygen (sO₂) values than Bekilli, Mahmutlu, and Sarayköy stations. In biomarker response evaluations, C. riparius larvae from Sarayköy, Sığma, Korucuk, and Güzelköy stations were found to exhibit inhibited acetylcholinesterase (AChE) activities (55%−68%) and elevated 7-ethoxyresorufin O-deethylase (EROD) activities (191%−281%), glutathione S-transferase (GST) activities (138%−187%), and metallothionein (MT) contents (155%−231%) when compared with the control values. This study proves that different stations are exposed to different pollution sources, the pollution level of a station varies depending on the season, and the stations on Çürüksu stream, among which Güzelköy appears to be the most contaminated, are exposed to more pollutants than those on the main tributary of the river.

Bu çalışma, mitokondriyal sitokrom c oksidaz alt birim I (COI) geni kullanılarak Türkiye’nin bazı bölgelerinden toplanan Paratanytarsus dissimilis’in (Diptera: Chironomidae) genetik çeşitliliğini, popülasyon yapısını ve demografik geçmişini incelemek için tasarlanmıştır. Bu amaçla, Türkiye’deki 7 popülasyonu temsil eden toplam 32 P. dissimilis larvası toplanmış, sekanslanmış ve analiz edilmiştir. Çalışma alanında toplam 15 haplotip tespit edilmiş ve bu haplotiplerin biri (H9) hariç hepsinin tek popülasyona özgü olduğu gözlenmiştir. Toplam popülasyon için nispeten yüksek haplotip çeşitliliği (h=0,95161) ve düşük nükleotid çeşitliliği (π=0,04624) bulunmuştur. Maksimum likelihood (ML) ve haplotip ağı incelemeleri bu 7 popülasyonun Doğu, Hatay ve Batı olmak üzere 3 gruba ayrılabileceğini göstermiştir. Moleküler varyans analizi (AMOVA) ve ikili FST karşılaştırmalarında, Türkiye’deki P. dissimilis’in farklı düzeylerde yüksek bir genetik yapılanma gösterdiği belirlenmiştir (p

This study was conducted to assess the acute toxicity of three previously synthesised 5-(3′-amino-4′-arylazo-1H-pyrazole-5′-ylazo) barbituric acid dyes (dyes 1–3) using Gammarus roeseli (Crustacea: Amphipoda) and Chironomus riparius (Insecta: Diptera) and to compare their sensitivities to these dyes. The toxicity of the tested dyes was found to increase with lengthened exposure period in both bioassays. The azo dye toxicity to both species was determined to increase due to the presence of the nitro and chloro groups in the structure. G. roeseli exhibited more tolerance to the nitro group containing azo dye (dye 2) than C. riparius, whereas C. riparius exhibited more tolerance to the chloro group containing azo dye (dye 3) than G. roeseli; however, the sensitivity of two species to the azo dye without these groups (dye 1) did not significantly differ. The results suggest that the sensitivity varies depending on the species and the azo dye structure and that both species are suitable for ecotoxicological tests of the azo dyes. Nevertheless, further studies are recommended to determine all aspects of the toxicity mechanisms of these azo dyes, to investigate their degradation products and to assess their actual risk in the environment based on the results of this study. GRAPHICAL ABSTRACT