scholarly journals Modeling coliform-bacteria concentrations and pH in the salt-wedge reach of the Duwamish River Estuary, King County, Washington

1976 ◽  
Author(s):  
W.L. Haushild ◽  
Edmund A. Prych
Author(s):  
Lani Febriana Safitri ◽  
Niniek Widyorini ◽  
Oktavianto Eko Jati

Perairan Muara Sungai Sayung terletak di wilayah Kabupaten Demak sebelah barat. Perairan ini telah dipengaruhi oleh berbagai aktivitas manusia yang menyebabkan terjadinya penurunan kualitas perairan. Bakteri Coliform merupakan bakteri gram negatif yang berbentuk batang dan tidak membentuk spora. Bakteri ini merupakan bakteri indikator terjadinya pencemaran perairan maupun indikator keberadaan bakteri patogen lainnya. Perhitungan total bakteri Coliform perlu dilakukan untuk mengetahui adanya pencemaran limbah organik yang terjadi di Perairan Muara Sungai Sayung, Morosari, Demak. Tujuan dari penelitian ini adalah untuk mengetahui kelimpahan total bakteri Coliform, dan status perairan di Perairan Muara Sungai Sayung, Morosari, Demak. Penelitian ini juga bertujuan untuk mengetahui hubungan dari jumlah total bakteri Coliform dengan bahan organik terlarut dan oksigen terlarut (DO). Pelaksanaan penelitian ini dilakukan pada bulan Mei 2018. Metode yang digunakan dalam penelitian ini adalah metode survei dan teknik pengambilan sampel menggunakan metode random sampling yang dilakukan pada lima stasiun. Hasil penelitian menunjukkan bahwa kelimpahan rata-rata total bakteri Coliform yang diperoleh berkisar antara 4 x 103 – 550 x 10 3/100ml. Kelimpahan rata-rata total bakteri Coliform yang diperoleh pada setiap stasiun menunjukkan bahwa kandungan total bakteri Coliform telah melebihi baku mutu air menurut Keputusan Menteri Lingkungan Hidup Nomor 51 Tahun 2004. Keberadaan total bakteri Coliform memiliki hubungan yang lemah dengan kandungan bahan organik terlarut, sedangkan keberadaan total bakteri Coliform memiliki hubungan yang cukup dengan oksigen terlarut (DO) di perairan Muara Sungai Sayung Morosari, Demak. Sayung River Estuary is located in the western part of Demak Regency. This estuary has been affected by various human activities which have led to a decline in water quality. Coliform bacteria are a gram-negative bacteria that are rod-shaped and do not form spores. This bacterium is an indicator bacteria of water pollution and an indicator of the presence of other pathogenic bacteria. Total Coliform bacteria calculation needs to be carrid out to find out if there any contamination of organic waste in Sayung River Estuary, Morosari, Demak.. The purpose of this research was to determine total abundance of Coliform bacteria, water quality in Sayung River Estuary, Morosari, Demak and relationship between the total abundance of Coliform bacteria with dissolved organic matter and dissolved oxygen (DO). This research was carried out in May 2018. The method that used in this research were survey method and the sampling technique was random sampling method in five stations. The results showed that the average abundance of total Coliform bacteria obtained ranged between 4 x 103 - 550 x 103 / 100ml. Average abundance of total Coliform bacteria obtained at each station shows that the total content of Coliform bacteria has exceeded the water quality standard according to Minister of Environment Decree number 51 of 2004. The total presence of Coliform bacteria has a weak relationship with the content of dissolved organic matter, while the total number of Coliform bacteria have sufficient relationship with dissolved oxygen (DO) in the Sayung River Estuary,Morosari, Demak.


2017 ◽  
Vol 52 (4) ◽  
pp. 469-487 ◽  
Author(s):  
Jin Hwan Hwang ◽  
Dongmin Jang ◽  
Yong Hoon Kim

2014 ◽  
Vol 18 (4) ◽  
pp. 1397-1411 ◽  
Author(s):  
L. C. Bruce ◽  
P. L. M. Cook ◽  
I. Teakle ◽  
M. R. Hipsey

Abstract. Oxygen depletion in coastal and estuarine waters has been increasing rapidly around the globe over the past several decades, leading to decline in water quality and ecological health. In this study we apply a numerical model to understand how salt wedge dynamics, changes in river flow and temperature together control oxygen depletion in a micro-tidal riverine estuary, the Yarra River estuary, Australia. Coupled physical–biogeochemical models have been previously applied to study how hydrodynamics impact upon seasonal hypoxia; however, their application to relatively shallow, narrow riverine estuaries with highly transient patterns of river inputs and sporadic periods of oxygen depletion has remained challenging, largely due to difficulty in accurately simulating salt wedge dynamics in morphologically complex areas. In this study we overcome this issue through application of a flexible mesh 3-D hydrodynamic–biogeochemical model in order to predict the extent of salt wedge intrusion and consequent patterns of oxygen depletion. The extent of the salt wedge responded quickly to the sporadic riverine flows, with the strength of stratification and vertical density gradients heavily influenced by morphological features corresponding to shallow points in regions of tight curvature ("horseshoe" bends). The spatiotemporal patterns of stratification led to the emergence of two "hot spots" of anoxia, the first downstream of a shallow region of tight curvature and the second downstream of a sill. Whilst these areas corresponded to regions of intense stratification, it was found that antecedent conditions related to the placement of the salt wedge played a major role in the recovery of anoxic regions following episodic high flow events. Furthermore, whilst a threshold salt wedge intrusion was a requirement for oxygen depletion, analysis of the results allowed us to quantify the effect of temperature in determining the overall severity and extent of hypoxia and anoxia. Climate warming scenarios highlighted that oxygen depletion is likely to be exacerbated through changes in flow regimes and warming temperatures; however, the increasing risk of hypoxia and anoxia can be mitigated through management of minimum flow allocations and targeted reductions in organic matter loading. A simple statistical model (R2 > 0.65) is suggested to relate riverine flow and temperature to the extent of estuary-wide anoxia.


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