Phytotoxicity of sediment from Gölcük Lake (İzmir, Turkey) on Desmodesmus (=Scenedesmus) dimorphus

Abstract

Gölcük Lake (Bozdağ-İzmir) is polluted by the touristic activities and agricultural and domestic sources. Gölcük Lake also adversely impacts human health as the lake water is used for irrigation in agriculture, and the fish caught from the lake is used for nutrition by the community around it. For this purpose, "OECD 201 Algal Growth Inhibition Test", the standard test protocol was evaluated with cultures of green algae Desmodesmus dimorphus as the representative of the first trophic level. This test was used to assess the toxicity of sediment samples collected from five sampling sites in Gölcük Lake. Extracts of sediment samples were assayed in four different concentrations (20, 40, 100, and 200 mg/ml). The effects on the growth of D. dimorphus were examined by scoring cell numbers under the light microscope with a Neubauer haemocytometer counting chamber. According to the results, all extracts, except those from Station 3, inhibited growth of D. dimorphus in increasing concentrations of sediment samples, and inhibition was observed in the following order of stations: 2>5>4>1. Additionally, an increase in the number of algae (hormesis) was observed in the Station 3, depending on time and concentrations. Keywords: Algal Growth Inhibition Test, Pollution, Freshwater, Gölcük LakeÖz: Gölcük Gölü (Bozdağ-İzmir) turizm aktiviteleri, evsel ve tarımsal kaynaklar nedeniyle kirlenmektedir. Gölcük Gölü'nün suyu tarımda sulama amaçlı kullanılmakta ve gölden beslenme amacıyla balık avlandığı için göl suyu, civarındaki halkın sağlığını da olumsuz yönde etkilemektedir. Bu amaçla, "OECD 201 Algal Büyüme İnhibisyon Testi" kısa zamanlı phytotoxicity test yöntemi için standart bir test protokolüdür ve yeşil alglerden olan Desmodesmus dimorphus kültürü birinci trofik seviye temsilcisi olarak değerlendirilmektedir. Bu test, gölden daha önceden belirlenmiş 5 örnekleme yerinden toplanan sediment örneklerinin toksisitesini değerlendirmek için kullanıldı. Sediment örneklerinin ekstraktları dört farklı konsantrasyonda (20, 40, 100 ve 200 mg/ml) test edildiler. Desmodesmus dimorphus'un büyümesi üzerindeki etkiler, sayma kamarası Neubauer hemositometre ile ışık mikroskopu altında hücre sayımı yapılarak değerlendirilmiştir. Sonuçlara göre, 3 numaralı istasyon dışında tüm sediment ekstraktları artan konsantrasyona bağlı olarak Desmodesmus dimorphus büyümesini engellemiştir ve bu istasyonlar sırasıyla 2>5>4>1 nolu istasyonlardır. Ayrıca 3 nolu istasyonda zamana ve konsantrasyona bağlı olarak alg sayısında artış (hormesis) gözlenmiştir.

A mutagenicity investigation of sediment from İzmir Inner Bay using Ames genotoxicity assay

“…When results of the present study were compared to those from the mutagenicity study conducted by Boyacıoğlu (1999) using TA100 strain of S. typhimurium, the mutagens responding to TA100 strain of S. typhimurium were observed to change from mutagenic to toxic characteristics (Dugan et al, 1990) in sediments from all 6 stations (Table 3, Figure 2).…”

“…There is a scarcity of ecotoxicological studies sediment of İzmir Bay sediment (Boyacıoğlu, 1999;Boyacıoğlu, 2004;Kutlu et al, 2008, Arslan et.al., 2010. The mutagenicity study of Ames conducted by Boyacıoğlu on İzmir Bay in 1999, is the first study conducted before the establishment of the Treatment Facility (2000) in the bay.…”

“…The first study on mutagenic characteristics of sediment from İzmir Bay was conducted by Boyacıoğlu as a doctoral dissertation along with BAP project in 1999 followed by a few genotoxicity studies (Boyacıoğlu, 2004;Arslan et al, 2010;Boyacıoğlu et al, 2011). Pollution status of the sediment which was a complex mixture hasn't been explored mutagenically in İzmir Inner Bay since the treatment facility (Big Canal Project) was launched in 2000.…”

A preliminary investigation of the effects of surface waters of the Bakırçay River on the growth of green algae Scenedesmus dimorphus

“…Another study was performed on sediment and water samples from Gölcük Lake; in that study, S. dimorphus was used in "Algal Growth Inhibition Assay" (OECD, 2011) to determine phytotoxic effect (Boyacıoğlu et al, 2017).…”