Assessment of organic pollution levels in the northern and middle parts of Shatt Al- Arab River by applying modified organic pollution index (OPI)

Abstract

Organic Pollution Index (OPI) was applied in this study to determine the levels of organic pollution in the northern and middle parts of Shatt AL-Arab River during the period from August (2011) to July (2012). Physical and Chemical variables were measured. The monthly variations in Organic Pollution Index for four stations were showed difference in values, The highest values 71 (Very Bad) was recorded in AL-Baradieah station and the lowest values 25 (Good) in Maaqal station. The seasonal variations in OPI ranged between (33-60) categorized between (Medium) and (Bad). Generally the mean value of OPI was 48 accordingly described as (Poor). Results of Principal Component Analysis (PCA) Showed that (temperature, dissolved oxygen, total suspended solids, chloride ion, electrical conductivity and pH) were the most effective variables on the levels of OPI, followed by (turbidity, nitrite and total organic carbon). there was no effect of chemical oxygen demand on OPI value.Key words: Shatt AL- Ara