Akarsulardaki Bakteriyolojik Su Kalitesinin Uzamsal-Zamansal Değerlendirmesi: Sansür Duyarlı Entegre Bir Yaklaşım (Harşit Çayı, Türkiye)

Yıl 2025, Cilt: 10 Sayı: 6, 913 - 922, 30.11.2025

Buse Eraslan Akkan , Cengiz Mutlu , Bülent Verep

https://doi.org/10.35229/jaes.1793470

Öz

Bu çalışma akarsulardaki bakteriyolojik kaliteyi değerlendirmek için tekrar üretilebilir, entegre bir çerçeve sunmaktadır. Sansür duyarlı Kaplan–Meier (KM) özetleri ile eşik olay yaklaşımını entegre ederek parametrik olmayan istatistiksel yöntemlerle uzamsal farklılıkları ve zamansal eğilimleri nicelleştirir. Bu amaç için Harşit Çayı’nın (Giresun, Türkiye) yedi farklı bölgesinden aylık yüzey suyu örnekleri steril koşullar altında toplanmış ve soğuk zincir protokolü kapsamında laboratuvara taşınmıştır. Su örneklerinin toplam koliform (TC), fekal koliform (FC), Escherichia coli (EC) ve fekal streptokok (FS) sayımları (MPN/100mL) bakteriyolojik kalitenin göstergeleri olarak kullanılmıştır. Bulgular, sağ sansürleme dikkate alınarak tanımlayıcı istatistikler ve KM özetleri kullanılarak incelenmiştir. Ayrıca, istasyon farklılıkları ve ilişkileri test edilmiştir. Dahası, çok değişkenli yapı ve kalite eğilimleri istatistiksel analizler kullanılarak değerlendirilmiştir. Bakteriyolojik kalite değerlendirmesi ulusal ve uluslararası kılavuzlara göre de yapılmıştır. Çalışmada KM özetleri, üst sınırda kümelenme nedeniyle sansürlemeye etkisini doğrulamıştır. Parametreler arasında geniş kapsamlı pozitif ve güçlü ilişkiler tespit edilmiştir (p<0,001). Tüm bakteriyel göstergelerde ortak bir gradyan tespit edilmiştir. Zaman içindeki eğilim, sadece İstasyon 2'de bir azalma göstermiştir. Ayrıca, istasyonlar açıkça yüksek yük (istasyonlar 6-7), düşük yük (istasyonlar 1-3) ve orta yük (istasyonlar 4-5; 2 daha yüksek ayrımla) kümelerine sınıflandırılmıştır. Sonuç olarak, KM tabanlı sansür duyarlı özetler ve eşik olay analizi bakteriyolojik akarsu verilerindeki sansürü bütüncül biçimde yönetmektedir. Bu sayede, karar vericiler ikameye dayalı yanlılıktan arındırılmış, eşik aşımı ne kadar sürede olacağını gösteren net risk göstergeleri görerek sürdürülebilir havza yönetiminde hızlı ve adil müdahaleleri kolayca gerçekleştirebilecektir. Bu uygulama, Türkiye’de akarsu bakteriyolojisine yönelik ilk sistematik KM uygulamalarından biridir ve farklı havzalara uygulanabilme potansiyeli taşımaktadır.

Anahtar Kelimeler

Su kalitesi , uzamsal-zamansal analiz , sansürlü veri , sağkalım analizi , çok değişkenli analiz , Harşit Çayı

Proje Numarası

BAP-C-250414-02

Spatiotemporal Assessment of Bacteriological Water Quality in Rivers: A Censoring-Aware Integrated Approach (Harşit Stream, Türkiye)

Öz

This paper presents an integrated, reproducible framework for assessing bacteriological quality in rivers. The aim is to quantify spatial variation and temporal trends with non-parametric statistics using censored Kaplan-Meier (KM) summaries and a threshold event approach. For this purpose, monthly surface water samples were collected under sterile conditions at seven stations on the Harşit Stream (Giresun, Türkiye), and transported to the laboratory under a cold chain protocol. Total coliform (TC), Fecal coliform (FC), Escherichia coli (EC), and fecal Streptococci (FS) counts (MPN/100mL) were used as indicators of bacteriological quality. Findings were examined using descriptive statistics and Kaplan–Meier summaries, considering right censoring. Furthermore, station differences and relationships were tested. Moreover, multivariate structure and quality trends were evaluated using statistical analyses. Furthermore, bacteriological quality assessment was performed according to national and international guidance. This study verified the effect of KM summaries on censoring due to clustering at the upper limit. Wide-ranging positive and strong relationships were detected between parameters (p<0.001). A common gradient was detected in all bacterial indicators. The trend over time showed a decrease only at Station 2. Furthermore, the stations are clearly classified into high load (stations 6–7), low load (stations 1–3), and intermediate load (stations 4–5; with 2 higher distinctions) clusters. In conclusion, KM-based censoring of sensitive summaries and threshold event analysis comprehensively manage censoring in bacteriological stream data. In this way, decision makers will realize the risk indicators that show how long it will take to exceed the threshold free from substitution-based bias. This will facilitate rapid and equitable interventions in sustainable basin management. This application is one of the first systematic KM applications for river bacteriology in Türkiye and has the potential to be applied to different watersheds.

Anahtar Kelimeler

Harşit Stream , spatiotemporal analysis , censored data , survival analysis , Water quality

Destekleyen Kurum

Giresun University

Proje Numarası

BAP-C-250414-02

Kaynakça

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