Enumeration and enzymatic activity of microorganisms in water and sediment of the Zarqa river

Abstract

The self-purification capacity and the water quality of the polluted Zarqa river and the non-polluted control Bahhath stream were assessed by comparing several physico-chemical and microbiological parameters in water and sediment. During the period April 1982 to April 1983 chemical para-meters such as biological oxygen demand, particulate organic carbon, ammonia and phosphate decreased 29 2, 10 and 5-fold respectively from Wadi Hajar to the Jarash bridge down along the river course. At the same time an increase in dis-solved oxygen was observed. Viable bacterial counts in water and sediments also decreased with down stream flow of the Zarqa river and were significantly higher than counts in the Bahhath stream. Amylolytic, lipolytic and proteolytic bacterial activities in water and sediments proved to be useful indicators for the self-purification capacity of the Zarqa river. Strong positive coorelations were obtained between total viable counts in water and sediments at all stations. Similar strong correlations were also obtained with hydrolytic counts at the polluted Wadi Hajar and Sukhna Stations but not at the Jarash bridge and Bahhath stations. This may indicate the autochthonous bacterial origin in the latter stations. Amylase and alkaline phosphatase activities in sediments were suitable for comparative purposes while lipase and protease activities were unreproducible, thus unreliable for making judgement about the self-purification capacity of the Zarqa river.