National Water Quality Research Articles

Comparison of detection limits estimated using single- and multi-concentration spike-based and blank-based procedures

Spike- and blank-based procedures were applied to estimate the detection limits (DLs) for example analytes from inorganic and organic methods for water samples to compare with the U.S. Environmental Protection Agency's (EPA) Method Detection Limit (MDL) procedures (revisions 1.11 and 2.0). The multi-concentration spike-based procedures ASTM Within-laboratory Critical Level (DQCALC) and EPA's Lowest Concentration Minimum Reporting Level were compared in one application, with DQCALC further applied to many methods. The blank-based DLs, MDLb99 (99th percentile) or MDLbY (= mean blank concentration + s × t), estimated using large numbers (>100) of blank samples often provide DLs that better approach or achieve the desired ≤1% false positive risk level compared to spike-based DLs. For primarily organic methods that do not provide many uncensored blank results, spike-based DQCALC or MDL rev. 2.0 are needed to simulate the blank distribution and estimate the DL. DQCALC is especially useful for estimating DLs for multi-analyte methods having very different analyte response characteristics. Time series plots of DLs estimated using different procedures reveal that DLs are dependent on the applied procedure, should not be expected to be static over time, and seem best viewed as falling over a range versus being a single value. Use of both blank- and spike-based DL procedures help inform this DL range. Data reporting conventions that censor data at a threshold and report “less than” that threshold concentration as the reporting level have unknown and potentially high false negative risk. The U.S. Geological Survey National Water Quality Laboratory's Laboratory Reporting Level (LRL) convention (applied primarily to organic methods) attempts to simultaneously minimize both the false positive and false negative risk when <LRL is reported and data between DL and the higher LRL are allowed to be reported.

Studi Perbandingan Efisiensi Perbaikan Mutu Air Limbah Domestik melalui Filtrasi Horizontal dengan Beton Porous Recycled Aggregate Berlapis

Domestic wastewater pollution is one of the reasons for the decline in the national Water Quality Index. The increasing number of people with inadequate sanitation facilities requires a solution. Porous concrete with RCA aggregate has the potential to improve domestic wastewater. Made of porous concrete, the filter is made with dimensions of 40×40×5 cm3 using RCA aggregate with 0.5-2.0 cm gradation. Two reactor models of the same size were prepared, containing 3 and 4 layers of filters. Domestic wastewater as a test object comes from Tlogomas Integrated Sewer System, flowed continuously into the model. The results of Test 1 show that the 3-Filters Reactor Model can improve the pH and COD values according to the quality standard, while the 4-Filters Reactor Model can only improve the pH value. The results of Test 2 show that the 3-Filters Reactor Model can improve the pH and TSS values according to the quality standard, while the 4-Filters Reactor Model can only improve the pH value. The average efficiency of the filtration against influent shows that the 3-Filters Reactor Model is better than the 4-Filters Reactor Model with the percentage of improvement in pH 11.54%, BOD 26.15%, COD 20.79%, and TSS 46.37%. However, in sediment trapping, the 4-Filters Reactor Model is superior with 112 mm compared to the 3-Filters Reactor Model which is 100.5 mm.

The Environmental Capacity of Hun River, Liaoning Province, China

Based on the environmental functional area allocation, point and non-point sources, hydrology and water quality data of Hun River, SWAT model is built and used to calculate the hydrological, water quality and environmental capacity processes in the river channel. The results showed: (1) When the upstream water quality concentration was limited to the grade III of the national surface water quality standard, the environmental capacity of total phosphorus (TP) in Hun River is about 582.01 t/a. (2) According to the results of water environmental capacity in different water periods, the environmental capacity of Hun River is seriously overloaded in the flood season, although annual value is satisfied the standard. For the strong driving effect on the pollutants transport in the river by the intense rainfall in flood season, the concentration in flood season exceeds the water quality standard of grade III. (3) To strengthen the environmental management of Hun River, it is necessary to monitor non-point sources in the cultivated land, standardize the fertilization measures, and improve the rural sewage pipe networks and related facilities.

The reduction process of petroleum content in marine oil spill in Jiaozhou Bay

According to the survey data about the waters of Jiaozhou Bay in May, September, and October 1993, this paper studies the content of PHC and its horizontal distribution in the surface waters of Jiaozhou Bay. The result shows that the range of PHC content in the waters of Jiaozhou bay is 4.16–51.00μg/L, which conforms to the national first, second and third water quality standards. In terms of PHC content, the water quality of Jiaozhou Bay is slightly polluted by PHC content in May, September and October. In May, the range of PHC content in the water of Jiaozhou Bay is 4.16–51.00μg/L, which is slightly polluted by PHC content. In the center of east waters, the water quality is slightly polluted by PHC content and the range of PHC content in other water fields of Jiaozhou Bay is 4.16–48.40μg/L which indicates that the water quality is not polluted by PHC content. In September, the range of PHC content in the waters of Jiaozhou Bay is 6.17–12.70μg/L, which is not polluted by PHC content. In October, the range of PHC content is 11.40–11.80μg/L, indicating that the waters of Jiaozhou Bay are not polluted by PHC. The content of PHC in the waters of Jiaozhou Bay only has one source, the transportation of marine oil spill, and the PHC content transported is 12.70–51.00μg/L. Therefore, as time changes, the ocean polluted by PHC content resulting from marine oil spill has gradually reduced over the course of the year. The marine oil spill has caused the waters in May to be slightly polluted by the PHC content. By September, the waters are not polluted by the PHC content. And then, in October, the marine oil spill has disappeared.

Low Cd content emitted by humans into the atmosphere

According to the data in May, September and October 1993, the variation range of Cd content in the water body of Jiaozhou Bay was 0.07-0.23μg/L, which conforms to the national water quality standard of Class I. It indicated that in May, September and October, the water in the entire water area of Jiaozhou Bay was not contaminated by Cd content. In May, the variation range of Cd content in the waters of Jiaozhou Bay was 0.09-0.18μg/L. In the coastal waters of the north of Jiaozhou Bay, the Cd content reached a relatively high value, which was 0.18μg/L. In September, the variation range of Cd content in the waters of Jiaozhou Bay was 0.07-0.23μg/L. In the coastal waters of the east of Jiaozhou Bay, the Cd content reached the highest value, 0.23μg/L. In October, the variation range of Cd content in the waters of Jiaozhou Bay was 0.08-0.18μg/L. In the coastal waters of the east of Jiaozhou Bay, the Cd content reached a relative high value, 0.18μg/L. In terms of Cd content, the water quality of Jiaozhou Bay had reached high quality. The water was clean, and it was not polluted by Cd content at all. The Cd content in the waters of Jiaozhou Bay mainly came from two sources, the transport of surface runoff and the transport of atmospheric deposition. The Cd content from surface runoff transportation was 0.18μg/L, and the Cd content from atmospheric deposition transportation was 0.18-0.23μg/L. The Cd content transported by atmospheric deposition was very close to the Cd content transported by surface runoff, and was very low, ranging from 0.18 to 0.23μg/L, far less than 1.00 μg/L. This revealed that the humans had realized the importance of environmental protection, and the emissions to the environment were very low. The atmosphere, land and sea were not polluted by Cd content. The Cd content transported by atmospheric deposition 0.18-0.23μg/L ≥ the Cd content transported by surface runoff 0.18μg/L, which indicated that the Cd content was mainly discharged into the atmosphere by humans and then deposited on the land.

Relationship between WQI, heavy metal and sedimentation in Sg Kenau, Kuantan, Pahang using WQ-HeMeS Model

The purpose of this study is to investigate the relationship between water quality of river with heavy metal and sediment content in Sungai Kenau at Pahang using new developed model named WQ-HeMeS. Through this study, water quality has been analysed by using Water Quality Index (WQI) & National Water Quality Standard for Malaysia (NWQS). Water quality of river in Sungai Kenau have been observed by several test which are Dissolve Oxygen, Biochemical Oxygen Demand, Chemical Oxygen Demand, Ammoniacal Nitrogen, Total Suspended Solid, Phosphorus and Nitrogen as Nitrate. Meanwhile, the sedimentation rate was determine using Schoklistch method and Duboy method. There are 2 condition for heavy metal considered in the analysis which are heavy metal in water and heavy metal in sediment. Heavy metal in water was tested using laboratory tools named as Atomic Absorption Spectroscopy (AAS) while heavy metal in sediment have been determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The classification of heavy metal in water have been done based on NWQS meanwhile heavy metal in sediment were observed based on Index of Geo-Accumulation and Metal Contamination Factor. After collecting all result from lab testing, the the relationship of water quality, sedimentation rate and heavy metal rate both in water and sediment was determine using generated model. Based on Malaysia WQI Standard, the result shown that water in Sungai Kenau is classified as Class I which means as for water supply, there are no treatment is necessary.

Hydrochemical assessment of the Beeshazar and associated lakes in Central Nepal

Water quality deterioration has threatened aquatic life around the world including Nepal, which has been a serious issue for environmental sustainability and economic development. This study evaluated and interpreted hydrochemical parameters of the Beeshazar and associated lakes in Central Himalaya, Nepal. The study revealed that the water in the lake was slightly alkaline as the average pH was 7.52. The correlation and principal component analysis (PCA) identified both geogenic and anthropogenic processes as the controlling factors of hydrochemistry whereas the cluster analysis (CA) showed relatively more pollution in the associated Laxmi Lake. Also, the water quality index (WQI) classified the water as “good” for drinking purposes (i.e., WQI = 33.90), while the pollution index (PI) values were characterized as sub-cleanness and slightly polluted. In general, both the WQI and PI signify that water in the lake complex is currently safe for drinking purposes. It is further confirmed from the comparative analysis of chemical variables with other lakes in the region, WHO and national water quality guidelines for aqua culture that the most of the analyzed water parameters exhibited relatively low concentrations and were within the prescribed guidelines. However, the elevated concentrations of NO3− and PO43− may pose serious problems for retaining water quality in the future. The results could be considered for future planning and management of the Ramsar Lakes of the lowland areas in the Himalaya and also as a valuable reference for the freshwater researchers at the national and international levels.

Determination of water quality in Universiti Malaysia Sabah (UMS), Kota Kinabalu: The effectiveness of stormwater management systems

Universiti Malaysia Sabah (UMS) campus in Kota Kinabalu consists of a large detention pond that stores the stormwater and limits the outflow rate into Likas' estuary. It is no doubt the detention pond has been designed per the Urban Stormwater Management Manual (USMM) requirement in terms of quantity control, however rapid development and changes in surrounding landscapes may affect the water quality. This study investigates the stormwater quality from the UMS detention pond and drainages within the campus. Water sampling was primarily taken during the dry period to justify worst-case scenarios without dilution from the rainfall season. Then the water quality parameters were tested using standard laboratory procedures mainly for Biochemical Oxygen Demand (BOD), Ammoniacal Nitrogen (AN), and Total Suspended Solids (TSS) with a minimum of a triplicate experimental run at the Environmental Laboratory, Faculty of Engineering, UMS. The determined water quality was compared with the National Water Quality Standards (NWQS) from the Department of Environment Malaysia. Overall the stormwater quality obtained for Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), AN and pH is within Class II to III, which is slightly polluted. However, the TSS from ponds near to main road and construction areas exceeds Class IV, indicating polluted conditions. There is a slight increase for BOD and AN parameters when comparing samples between June 2020 (post-MCO) and January 2017, which was suspected briefly due to fertilizing work for the campus landscapes. Although the TSS value is low, the TSS volume would increase over a period, raising the temperature while reducing the DO concentration and endanger the aquatic species and the ecosystem. Hence, it is recommended for a future study to emphasize TSS value as it would contribute significantly in designing sustainable stormwater management, particularly for the stormwater treatment, such as when optimizing for the utilization of alternative filter media, which reduces the maintenance and increasing the lifespan of the system.

A study of spatial and water quality index during dry and rainy seasons at Kelantan River Basin, Peninsular Malaysia

A study was conducted to identify the water quality status of Kelantan River Basin, Peninsular Malaysia, covering five sub-catchments (Nenggiri, Galas, Lebir, Pergau, and Kelantan downstream (DS)) during the dry and rainy seasons. Water samples were collected from 27 sampling stations along the Kelantan River at the years 2017 and 2018. The data consists of temperature, pH, total suspended solid (TSS), dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonia nitrogen (AN), nitrate (NO3), phosphorus (P), and manganese (Mn). The water quality status was identified by calculating the water quality index (WQI) based on the National Water Quality Standards for Malaysia (NWQS) using six parameters. The study explores the spatial approach in assessing water quality status to produce an assessment index. Results showed that water quality status during the dry season at Kelantan River Basin was in class III for all sub-catchments, where the water can only be used for livestock drinking and tolerant species of fishes. Meanwhile, the quality of the water during the rainy season was in class III for the sub-catchments of Lebir, Pergau, and Kelantan DS. The Galas’ sub-catchment was in class IV, and the Nenggiri’s sub-catchment was experiencing the worse condition (in class V). Overall, the water quality in the Kelantan River Basin is at a moderate level, whereby more focus on the Nenggiri’s and the Galas’ sub-catchments should be take it seriously to ensure that the river water pollution levels in Kelantan are well under control.

Water quality status of Sungai Petani River, Kedah, Malaysia

Water is one of crucial natural sources for all livings. However, as the burgeoning population growth and excessive development, the quality of water is deteriorated. Hence, assessing the quality of river water is pivotal not only for determining water quality condition but also identifying polluted areas. This study was conducted to determine water quality status of Sungai Petani River located in Kedah, Malaysia involving three sampling stations (S1, S2 and S3). Six water quality parameters were determined following APHA standard method. The results then assessed following Water Quality Index (WQI) assessment and evaluated based on National Water Quality Standards (NWQS) for Malaysia. Both dry and wet seasons shows increasing index value. In wet season the results were 51.33, 73.06 and 74.76 for S1, S2 and S3 respectively while for dry season index value of 47.97, 58.04 and 69.60 for S1, S2 and S3. Increasing index value from upstream to downstream (S1 to S3) indicates the water quality status was from polluted to slightly polluted (S1 to S3) due to pollutant load from nearby activities. The overall classification for the river water was in class III, the uses for this classification water are water supply with the need for an extensive water treatment and fishery and livestock drinking.

The Lowest Deposition of Hg Content is in the Jiaozhou Bay Center

Based on the investigation data of Jiaozhou Bay in 1992, this thesis studied the present situation and horizontal distribution of Hg content in the bottom of Jiaozhou Bay mouth. The results showed that in May, August and October, the range of Hg content in the bottom ofJiaozhou Bay was 0.007-0.040 μg/L, which was in line with the national water quality standard for class I seawater. This showed that in terms of Hg content, the bottom water of Jiaozhou Bay from the center of the bay to the south of the bay mouth was not polluted by any Hg content in May, August and October. In the bottom of Jiaozhou Bay, in May, the range of Hg content in Jiaozhou Bay was 0.013-0.019 μg/L. In August, the range of Hg content in Jiaozhou Bay was 0.021-0.025 μg/L. In October, the range of Hg content in Jiaozhou Bay was 0.007-0.040 μg/L. Therefore, in May, August and October, the water of Jiaozhou Bay was not polluted by any Hg content. In May, a high sedimentation of Hg contentwas in the coastal waters of the eastern part of the Bay. In August, a high sedimentationof Hg content was in the coastal waters and the estuary waters in the east of the Bay. In October, a high sedimentation of Hg content was in the south of the bay mouth. However, from May to August, and then to October, the lowest Hg content sedimentationwas in the central waters of the Bay.

Mapping the Soil Vulnerability Index across broad spatial extents to guide conservation efforts

<h3>THE NEED FOR TARGETED AGRICULTURAL CONSERVATION</h3> The 2008 Gulf of Mexico Hypoxia Action Plan was developed in response to national water quality impairments that were largely caused by agricultural land uses within and around the US Corn Belt (Alexander et al. 2008; Mississippi River Gulf of Mexico Watershed Nutrient Task Force 2008). The plan prompted states to create nutrient reduction strategies to achieve a 45% reduction in total nitrogen (N) and total phosphorus (P) loads into the Mississippi River, and thereby alleviate the hypoxic zone in the Gulf of Mexico (Mississippi River Gulf of Mexico Watershed Nutrient Task Force 2008). Similar to other state strategies, the Iowa Nutrient Reduction Strategy (INRS) promotes the widespread and voluntary adoption of best management practices (BMPs) to achieve nutrient reduction goals. The INRS establishes goals of 41% and 29% reductions in total N and total P, respectively, from nonpoint sources from a 1980 to 1996 baseline (Iowa Department of Agriculture and Land Stewardship et al. 2017). These goals are largely dependent on regional conservation funding and infrastructure to inform and incentivize BMP adoption at individual farm scales (Zimmerman et al. 2019a).

Trend Of Water Quality Status In Kelantan River Downstream, Peninsular Malaysia

The issues of freshwater pollutions and the high demand of clean freshwater for daily human activities have forced developing countries such as Malaysia to continuously monitor the quality of the freshwater. The present study objective is to present the trend of water quality status in the Kelantan River downstream, Peninsular Malaysia from 2005 to 2018. Water samples were collected during dry and monsoon seasons from a sampling station located at downstream of the Kelantan River. Water quality parameters such as temperature, pH and dissolved oxygen (DO) were measured in situ while other parameters were analysed in the laboratory based on retrieved water samples. Water quality status was determined based on National Water Quality Standard (NWQS) for River in Malaysia by calculating the water quality index (WQI) according to the concentration of six water quality parameters involving pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (TSS) and Ammonia Nitrogen (AN). The results showed that Kelantan River had good water quality during the dry season classified in Class II at 2005. The water quality was found to be slightly lower during the monsoon season in year 2006. In addition, increasing the number of construction, human activities in the land use areas, land use changes and the sewage water from domestic, industrial, wet market and food outlets in the Kelantan State have declined the water quality in Kelantan River from Class II (in 2005) to Class III (in 2010 and 2011) and to become Class IV in 2017 to 2018. The results of the present study are expected to give valuable information for the water managers in order to deal with better strategies in controlling the quality of freshwater at the Kelantan River and minimize the incidence of pollution-oriented problems, thus the water can be utilized for various water uses with appropriate quality.

Biochemical Oxygen Demand, Nitrogen, Phosphorus and Navigational Carrying Capacities of Bengoh Reservoir for Potential Aquaculture and Recreational Developments

This paper quantifies the biochemical oxygen demand (BOD), nitrogen (N), phosphorus (P) and navigational carrying capacities of Bengoh Reservoir for potential fish cage culture and recreational developments. The pollutant degradation coefficients (k) and pollutant carrying capacities (tons/day) of the reservoir were determined. The computed pollutant degradation coefficients were primarily based on the hydrological information of the catchment, hydraulic and operational details of the dam, and the targeted water quality standards of the river-connected Bengoh Reservoir. The maximum allowable pollutant loading rate (tons/year) defines the reservoir’s maximum Waste Assimilative Capacity (WAC) on specific pollutants (BOD, N and P), while in compliance to the targeted benchmark with the receivable pollutant loadings. It was found that the current BOD, TN and TP loading rates are 0.308 ton/day, 0.119 ton/day and 0.114 ton/day, respectively. To comply with Class I Standards of the National Water Quality Standards of Malaysia (NWQSM), the Maximum Allowable Loading Rates of BOD can be as high as 92.24 tons/day as compared to the current loading rate of 0.308 ton/day, maximum TN loading of 116.63 tons/day versus current 0.119 ton/day, and maximum TP loading at 125.54 tons/day versus current 0.114 ton/day. It was also found that the maximum number 218 cages (225 fish/cage) of Tilapia would be allowed in Bengoh Reservoir so as to comply with Class I of NWQSM. Based on the peak level of the reservoir recreational types of use in demand and the mix of public and private access, the navigational carrying capacity of the reservoir was estimated to be about 130 boats.

Calculating Aqueous Environmental Quality Standards to Protect Human Health: Derivation of a Predicted No-Effect Concentration.

Efforts to establish water quality standards for the protection of human health involve a calculation of the amount of fish that can be consumed without exceeding a predetermined safe dose. This article is protected by copyright. All rights reserved.

The influence of Cd Content Transported by Different Sources on Different Surface and Bottom Layers

According to the investigation data of Jiaozhou Bay in 1992, the vertical distribution, horizontal distribution and seasonal variation of Cd in the surface and bottom waters from the center of the bay to the south of the mouth of Jiaozhou Bay are studied, and the seasonal distribution, range of distribution and horizontal distribution trend are determined. The results show that in May, August and October, in the waters from southern mouth to the center of the bay, the Cd content of surface and bottom waters ranged from 0.12-1.19μg/L, in line with the national water quality standards for Class I and Class II seawater, which indicates that water quality was slightly polluted by the Cd content orwas not polluted. The surface levels of Cd vary seasonally from low to high: spring, summer, and fall, the same was true for Cd seasonal variation in bottom waters. In the surface and bottom waters of Jiaozhou Bay from the south of the bay mouth to the center of the bay, in May, August and October, when the Cd content in surface waters was relatively low, and the corresponding bottom layer was relatively low; when the Cd in surface waterswas relatively high, the corresponding bottom layer was relatively high; this shows that the loss of Cd content both from the surface and the bottom was relatively high. In May, August and October, in the waters from the southeast of the bay to the center of the bay, the horizontal distribution of Cd in the surface and the bottom waters have an opposite trend. From May to October, the seasonal variation of Cd content in surface waters in the southeast of the bay was mainly affected by the Cd content transported by main sea currents, while the bottom waters are mainly affected by river-transported Cd content. From May to October, in the central waters of Jiaozhou Bay, the seasonal changes of surface and bottom Cd content are not consistent withthat of Cd content transported by main sea currents. On the temporal scale, in the waters of Jiaozhou Bay from the south of the bay to the center of the bay, in May, August and October, the Cd content in the surface and bottom watersvariateswithin the same range, maintaining the consistency. On the spatial scale, in the waters from the southeast of the bay to the center of the bay, in May, August and October, according to the comparison between the Cd content transported by main sea currents and that transported by rivers, it can be proved that the horizontal distribution of Cd content in the surface waters was opposite to that of in the bottom waters.

Estimated prenatal exposure to nitrate in drinking water and birth defects: A population-based cohort study of over half a million births in Denmark

Background/Aim: Prior studies have yielded inconsistent evidence from prior studies of an association between nitrate in drinking water and an increased risk of birth defects (BDs). The aim of this study was to assess maternal exposure to nitrate in drinking water and BDs in a large population-based cohort with high-quality individual-level exposure estimates.Methods: A cohort of 564,232 singleton live births that occurred among Danish parents during 1994-2004 was identified from the Danish Birth Registry and information on BDs was obtained from ICD-10 codes within the Danish National Patient Register. Estimates of average nitrate concentrations in drinking water during each pregnancy were linked to these births using data from a national water quality registry. Logistic regression with generalized estimating equations was used to assess the relationship between nitrate exposure and BDs and account for multiple births to the same mother. Nitrate exposure was modeled as both a categorical and continuous variable.Preliminary Results: In total, 31,568 cases of BDs were identified, including 8,101 congenital heart defects, 2,581 urinary defects, 1,986 orofacial clefts, and 1,662 digestive system defects. An elevated risk of any birth defect [adjusted odds ratio: 1.05 (95% confidence interval: 1.01, 1.09)] was observed when comparing the highest quartile of exposure (≥4.9 mg/L NO3-) to the lowest (≤1.1 mg/L NO3-). There was also evidence of a positive exposure-response in models using categorical (p for trend=0.02) and to a lesser extent for continuous (p=0.06) nitrate exposure. No clear evidence of an association was observed between nitrate and specific BDs.Conclusions: Our study is the most statistically powerful study to date examining the relationship between nitrate in drinking water and BDs. Maternal nitrate exposure was associated with increased risk of BDs and at levels below current drinking water standards, adding to the evidence that the current standard is not sufficiently protective.

Monitoring of river and marine water quality at Sarawak baseline

The water quality for the shorelines of Kuching, Samarahan, and Betong divisions was assessed based on the primary and secondary data which was then compared to the National Water Quality Standards and Marine Water Quality Criteria and Standards for Malaysia. The Water Quality Index (WQI) and Marine Water Quality Index (MWQI) were generated where applicable. The results reveal that the baseline river monitoring locations portrayed slight pollution with WQI ranging from 60 to 80 except for Sg. Seblak station with polluted water quality, registering WQI of 42. Most of the baseline marine water monitoring stations recorded excellent to moderate MWQI apart from Btg. Samarahan and Sg. Sarawak stations with MWQI of 40, which might be due to the urban population of the Kuching city and Samarahan area. Moreover, MWQI of 48 was recorded at the estuary of Sg. Tabo and Sg. Buntal. The primary data revealed that the marine water samples had a dissolved oxygen (DO) concentration between 4.58 and 6.88 mg/L. The heavy metal ions and oil and grease parameters were below the detection limit. Hence, no industrial-related effluent was detected at the estuary and coastal waters along the shoreline of Kuching, Samarahan, and Betong. The present study concluded that the main pollutants along the shoreline of Kuching, Samarahan, and Betong include ammoniacal nitrogen (NH3–N), nitrate nitrogen (NO3–N), and phosphate (PO4). The high levels of NH3–N, NO3, and PO4 are attributed to the wastewater discharges originating from coastal settlements and commercial establishments, nutrient runoffs from large-scale agricultural activities, and aquaculture activities. In contrast, the secondary data revealed the presence of faecal pollution originating from untreated or partially treated sewage and sullage discharged by coastal settlements and commercial establishments.

Water quality evaluation of two urban streams in Northwest Uruguay: are national regulations for urban stream quality sufficient?

Poor water quality in urban streams places at risk the health of urban residents and the integrity of urban environments, ultimately leading to the "urban stream syndrome." In response to growing concerns regarding urban streams in Uruguay, we evaluated the spatiotemporal variation in water quality parameters in two urban streams, the Ceibal and La Curtiembre streams, over 12-18months. A proposal for an Urban Water Quality Index (UWQI) was developed based on national water quality standards for two stream classes to assess variability in overall stream condition over time. Both streams displayed extremely high levels of fecal coliform concentrations in mid-downstream sites and relatively high levels of total dissolved phosphorus and ammonia well above the national standards of 0.025mg/L and 0.02mg/L, respectively. Nitrate was consistently below the national maximum of 44.3mg/L, calling to question the adequacy of this standard for designated uses. Over 40% of samples had oxygen levels below the national standard of 5mg/L, and a dead zone (average 1.5mg/L) was detected in the downstream reach of the La Curtiembre stream. Despite differences in land use and urban context, monthly observations of nutrients and coliforms indicated high levels of contamination in mid-downstream reaches, which could present a health risk for the populations in Paysandú and Salto. This study highlights the degradation of urban streams in two major cities in Uruguay and the need for a comparative diagnosis of stream condition as a basis for decision-making regarding urban development and water resources.

Increased Transparency and Resource Prioritization for the Management of Pollutants From Wastewater Treatment Plants: A National Perspective From Australia

With increasing human populations in coastal regions, there is growing concern over the quality of wastewater treatment plant (WTP) discharge and its impacts on coastal biodiversity, recreational amenities, and human health. In Australia, the current system of WTP monitoring and reporting varies across states and jurisdictions leading to a lack of data transparency and accountability, leading to a reduced ability to comprehensively assess regional and national scale biodiversity impacts and health risks. The National Outfall Database (NOD) was developed to provide a centralized spatial data management system for sharing and communicating comprehensive, national-scale WTP pollutant data. This research describes the structure of the NOD and through self-organizing maps and principal component analysis, provides a comprehensive, national-scale analysis of WTP effluent. Such a broad understanding of the constituents and level of pollutants in coastal WTP effluent within a public database provides for improved transparency and accountability and an opportunity to evaluate health risks and develop national water quality standards.