Current Water Quality Standards Research Articles

Key Issues and Challenges in Establishing Regionally Differentiated Water Quality Standard in China

The goal of environmental management in China is transitioning from pollution control to the improvement of ecological quality. The establishment of regional differential water quality standards can better adapt to the ecological characteristics and development needs of different regions. Given the shortcomings of current water quality standards and the needs of technological development, this study analyzed the causes and influencing factors of regional differences in water quality standards and summarized China's regional variations in areas such as the characteristics of receiving water bodies, social attributes, climate conditions, physicochemical properties of water, and aquatic biotic populations. It also examined the impact of regional characteristics on the assessment of biological toxicity. Based on these analyses, the study identified key scientific questions that may arise in the development of regional differential water quality standards in China and outlined future critical research directions in this field. These directions include developing theories and methods for determining the effluent dilution coefficient, establishing methods for identifying regional key water quality indicators and assessing their impact on water quality standards, determining regional characteristic species and their influence on water quality standards, and formulating theories and methods for categorizing different regions across the country. The aim of the study was to provide a reference for the scientific establishment of water quality standards in China.

Porous Materials for Water Purification

AbstractWater pollution is a growing threat to humanity due to the pervasiveness of contaminants in water bodies. Significant efforts have been made to separate these hazardous components to purify polluted water through various methods. However, conventional remediation methods suffer from limitations such as low uptake capacity or selectivity, and current water quality standards cannot be met. Recently, advanced porous materials (APMs) have shown promise in improved segregation of contaminants compared to traditional porous materials in uptake capacity and selectivity. These materials feature merits of high surface area and versatile functionality, rendering them ideal platforms for the design of novel adsorbents. This Review summarizes the development and employment of APMs in a variety of water treatments accompanied by assessments of task‐specific adsorption performance. Finally, we discuss our perspectives on future opportunities for APMs in water purification.

Porous Materials for Water Purification.

Water pollution is a growing threat to humanity due to the pervasiveness of contaminants in water bodies. Significant efforts have been made to separate these hazardous components to purify polluted water through various methods. However, conventional remediation methods suffer from limitations such as low uptake capacity or selectivity, and current water quality standards cannot be met. Recently, advanced porous materials (APMs) have shown promise in improved segregation of contaminants compared to traditional porous materials in uptake capacity and selectivity. These materials feature merits of high surface area and versatile functionality, rendering them ideal platforms for the design of novel adsorbents. This Review summarizes the development and employment of APMs in a variety of water treatments accompanied by assessments of task-specific adsorption performance. Finally, we discuss our perspectives on future opportunities for APMs in water purification.

The impact of diet on wastewater treatment works phosphorus loading

ABSTRACT Phosphorus (P) is a building block for life in which the human body requires 0.55 g of per day. In some cases, this requirement is exceeded by 2 g per day, with P additives contributing to half of this exceedance. The use of P has become prominent as demand for processed convenience foods has increased. P can cause significant eutrophication once discharged to the environment. As of October 2019, 55% of assessed rivers and 73% of assessed lakes in England failed the current water quality standards. A survey was conducted to calculate the average P consumption of individuals who identify as meat eaters, flexitarians, vegetarians and vegans based on stated eating habits and reported P levels in foods, revealing an estimated P consumption of 1715, 1664, 1244, 1125 mg P/day respectively. It was estimated that current diets contribute 45% of the P load to UK wastewater treatment works (WwTW). If the UK population were to all convert to veganism this would decrease by 54% reducing the load to WwTW by over 15,000 tonnes of P per year, or 9000 tonnes of P per year if there was a move towards a 50% vegetarian or vegan population. Finally, the population needs to be better informed on what is in their food and the associated environmental impacts.

A method to determine water quality categories based on biotic index of macroinvertebrates in the Yangtze River Delta

China's current water quality standards (WQS) were first established in the 1980s referring the other countries' experience in setting environmental criteria and may not be suitable for the circumstances in China. Thus, it is necessary to improve the theories and methodologies of WQS. This paper provided a promising method to determine water quality categories based on biotic index of macroinvertebrates. Firstly, systematic ecological investigations were conducted and the biotic index of macroinvertebrates were used to assess the river health. Then, the statistical analyses and the driving effects of water quality factors on biological communities were identified. Futhermore, the relationship between cumulative mean of biotic index of macroinvertebrates and its derived factor was established. Finally, ecological thresholds for water quality base on biotic index of macroinvertebrates were obtained. The novel method was carried out in the Yangzhou city of the Yangtze River Delta, China. The biological samples were comprised of total 59 invertebrate taxa from 30 sites in Yangzhou city. Biotic index assessment shown that 16.7% of the sites were very healthy in summer and 8.3% of the sites were very healthy in winter. The most important hydrological factor affecting macroinvertebrate species was NH4-N in summer and CODMn in winter. Finally, the benchmark of NH4-N and CODMn deriving from macroinvertebrates tolerance values was obtained. This work can provide important information for pollution management in ambient aquatic ecosystem for decision makers.

The pathways influence of agricultural expansion on water quality of fish farming in Ilha Solteira reservoir, São Paulo, Brazil

It is widely accepted that fish farms (FF) have important contribution to input of nutrients into water, however fundamental knowledge regarding the influence of land use and land cover (LULC) on the water quality of fish farms is still lacking. The aim of this study was to assess the linkages between the LULC types and the water quality parameters in FFs. Three specific objectives were set: (1) to characterize the current water quality standards in four FFs (FF1, FF2, FF3, FF4) installed in the Ilha Solteira reservoir; (2) to delineate and analyze the LULC changes in sub-basins of tributaries where FFs are installed; (3) to elucidate the interactions between LULC and water quality in FFs. Results indicated signs of eutrophication in FF2 in both the dry and wet seasons. The mainly LULC was decrease of pasture and increase of sugarcane crops were observed in the four FFs' sub-basins between 2005 and 2018. Sugarcane land uses showed a significant positive correlation with SO4, Mg and K (r > 0.95, p < 0.005). The most likely source of these highlighted parameters may come from mineral fertilization, decomposition of the plinth in sugarcane and the application of vinasse to irrigate and fertilize crops. Concentrations of SO4, Mg and K observed in this present study do not cause direct toxic effects to Nile tilapia in fish farms. However, indirect impacts to water quality should be expected due to enhance primary production and promotes water eutrophication, as observed in FF2. Based on our results, we suggest that the criteria “basin characteristics”, including future sugarcane expansions, should be adopted to gather information in identifying areas more suitable for aquaculture parks that the Brazilian government intends to install in the large reservoirs.

National status of state developed and implemented forestry best management practices for protecting water quality in the United States

United States forestry best management practices (BMPs) were developed by U.S. states to protect water quality while enhancing the sustainability of forest management activities. Forestry BMPs are revised over time or new BMPs are written to meet current water quality standards. Properly implemented forestry BMPs have been found to minimize the impact of erosion and sediment that may occur during forest management activities. States developed implementation strategies to help determine if BMPs are being implemented correctly; however, these strategies can vary between regions and states making implementation results difficult to interpret. Few studies have compared monitoring strategies and implementation of BMPs on a national level. This study surveyed and received responses from state forestry agencies in all 50 states. Each state reported a documented BMP manual. Twenty states reported non-regulatory BMP guidelines, 19 reported quasi-regulatory BMP guidelines, and 11 reported regulatory BMP guidelines. Thirty-nine states have BMP monitoring programs with the state forestry agency as the lead agency in 35 states. BMP effectiveness studies were reported in 33 states with 19 states reporting current or future effectiveness studies. Thirty-two states reported that they have conducted BMP implementation studies resulting in a mean national BMP implementation rate of 91%. However, when evaluating implementation of individual BMP categories, the survey indicated potential deficiencies for some states, yet these states’ overall BMP implementation rate appear to be satisfactory. There was no significant difference between non-regulatory, quasi-regulatory, and regulatory BMP guidelines when compared by mean state BMP implementation rates (90.2%, 90.2%, and 93.4%, respectively). Mean BMP implementation rates for the western (93.2%) and southeastern (92.4%) regions were significantly higher than the northeastern region (86.4%). This assessment of state BMP programs indicates that BMP programs appear to be implemented at relatively high levels across the U.S. These findings should be useful globally for agency managers to improve program effectiveness and better understand BMP implementation and program structure among 50 diverse states.

Pelagic phytoplankton community change‐points across nutrient gradients and in response to invasive mussels

Summary Phytoplankton communities can experience nonlinear responses to changing nutrient concentrations, but the nature of species shifts within phytoplankton is not well understood and few studies have explored responses of pelagic assemblages in large lakes. Using pelagic phytoplankton data from the Great Lakes, we assessed phytoplankton assemblage change‐point responses to nutrients and invasive Dreissena, characterising community responses in a multi‐stressor environment and determine whether species responses to in situ nutrients can be approximated from nutrient loading. We demonstrate assemblage shifts in phytoplankton communities along major stressor gradients, particularly prominent in spring assemblages, providing insight into community thresholds at the lower end of the phosphorus gradient and species‐stressor responses in a multi‐stressor environment. We show that responses to water nutrient concentrations could not be estimated from large‐scale nutrient loading data likely due to lake‐specific retention time and long‐term accumulation of nutrients. These findings highlight the potential for significant accumulation of nitrates in ultra‐oligotrophic systems, nonlinear responses of phytoplankton at nutrient concentrations relevant to current water quality standards and system‐specific (e.g. lake or ecozone) differences in phytoplankton responses likely due to differences in nutrient co‐limitation and effects of dreissenids.

Response Behaviors of Heavy Metals at Tidal Currents Interface and Salinity Interface in the Estuary Area

In China, trace metals (such as dissolved Cu, Zn, Pb, Cd, and Cr) are the routine mandatory monitoring indicators in existing Freshwater Quality Standard (FWQS, 2002) and Seawater Quality Standard (SWQS, 1997). Using Daliao River estuary as an example, we tried to research the general response patterns of these metals in estuarine system. Firstly, we determined the location of FSI (freshwater-seawater interface) and TCI (tidal currents interface), which were based on biological, chemical and geographic similarities by descriptive and quantitative methods, respectively. Secondly, two hypotheses were proposed to explain the difference based on distribution coefficient Kd along salinity and SS (suspended solids) gradient, these results revealed that the indicators for As, Cd and Cr may be prone to be affected by salinity, and the ones in the second pattern may be more sensitive to SS. Finally, we classified the response behaviors into two patterns based on the changing trends along the distance and magnitudes affected by the FSI and TCI: 1the obvious boundary break point from FSI for As, Cd and Cr; 2 the boundary zones from TCI for Zn, Cu, Pb and Ni. The partitioning behaviors showed similar changing trends at particle and sediment phases, especially for particle phase, depending on the concentration of SS along the salinity. The difference between general behaviors for the two patterns mainly existed at water phase. In general, this paper highlighted the need to consider the background difference of trace metals and identified the sensitive indicators controlled by different environment factors (such as salinity and SS) based on the native estuarine characteristics. Our work will assist the implementation of updating the current water quality standards in China.

Molecular Alternatives to Indicator and Pathogen Detection: Real-time PCR

Microbial quality of water is a prime public health concern in today's world. To protect public health, the World Health Organization and the U.S. Environmental Protection Agency have established microbial pollution indicator standards and recommended routine monitoring of water for both total and fecal coliforms (Dufour, 1984, U.S. EPA 1986,1994, WHO 1993). However, the adequacy of current water quality standards to indicate the presence or absence of human pathogens is still questionable. For example, human viruses are more resistant to sewage treatment processes and environmental conditions than bacterial indicators and therefore may pose a substantial threat. It is now recognized that the absence, or a low concentration, of indicator organisms in water may not adequately reflect the absence of human viruses. In our previous study of southern California coastal waters, we found over 30% of coastal waters tested contained human viruses, and the presence of these viruses did not correlate with an elevated level of bacterial indicators (Jiang et al. 2000). The goal of this research is to develop and validate a molecular method for rapid and specific detection of microbial contaminants including human viruses and bacterial indicators in treated sewage effluents and receiving waters. This title belongs to WERF Research Report Series ISBN: 9781843397359 (Print) ISBN: 9781780404486 (eBook)

Ecotoxicity of Imidacloprid to Aquatic Organisms: Derivation of Water Quality Standards for Peak and Long-Term Exposure

ABSTRACTThe neonicotinoid insecticide imidacloprid is among the pesticides that most frequently exceed current water quality standards in Dutch surface waters. Recent research shows that effects of imidacloprid on water organisms occur at concentrations below these standards. Mayflies appear to be particularly sensitive with chronic No Observed Effect Concentrations in the nanogram per liter range. The aim of this study was to derive updated water quality standards in accordance with the methodology of the European Water Framework Directive by evaluating the available recent literature on acute and chronic ecotoxicity of imidacloprid to aquatic organisms in laboratory and semi-field experiments. It is concluded that the standard for long-term exposure should be lowered to 8.3 nanograms per liter; the standard for short-term concentration peaks can be maintained at the current value of 0.2 micrograms per liter. The European Commission set restrictions to the use of imidacloprid-based products to reduce the risks for bees and the Dutch national authorities issued emission reduction measures to protect aquatic life. Future monitoring data will ultimately reveal if these measures are sufficient to meet the newly proposed standards.

Development and implementation of surface water quality standards for protection of human health in Korea

Current water quality standards for the protection of human health in Korea include 17 substances found in rivers and streams. Due to increasing concern over the release of hazardous chemicals into the aquatic environment, there has been a demand for additional water quality standards. Therefore, the Korean Ministry of the Environment plans to gradually increase the number of water quality standards to 30 substances, including 22 substances for protection of human health and 8 substances for protection of aquatic ecosystems by 2015. In this study, new water quality standards for protection of human health were established for 1,4-dioxane, formaldehyde, and hexachlorobenzene. We selected candidate hazardous chemicals, conducted a human health risk assessment to determine priority chemicals, established water quality standards based on technical analyses and comparison with domestic and developed countries' water quality standards, and conducted an expert review. Water quality standards for protection of aquatic ecosystems will be derived in the near future. This study describes how the water quality standards for protection of human health were developed and implemented. Current status, recent expansion, and future plans for water quality standards in Korea are also covered.

Biotic Ligand Models for Metals—A Practical Application in the Revision of Water Quality Standards in China

T current water quality standards (WQS) in China were issued in 2002. 1 According to the surface water environmental function classification and protection target, all surface waters are divided into five classes. Class I waters generally have the most stringent WQS and Class V the least stringent. The WQS have played an important role in China. However, they need to be updated to better reflect the latest advances in research, and regional water quality characteristics of Chinese waters. Chinese regulators are planning to begin revisions to the national WQS by the end of year 2012. Because there is currently no scientific research being directed at the development of water quality criteria (WQC) or WQS that are specific to China, a common approach is to build upon the successful WQC experiences of other countries. 2 To some extent, current WQS for some chemicals might under-protect or overprotect freshwater aquatic species. 3 The reason is that many WQS fail to consider how site-specific water chemistry influences the bioavailability and toxicity of chemicals to aquatic life. So, it is imperative to carry out WQC research to support the updating of WQS in China. A bioavailability-based method should be used to harmonize the approach for setting WQS for metals in China with the current understanding of how water quality influences the effects of metals on aquatic organisms. Efforts to incorporate the influence of water chemistry on metal bioavailability into the derivation of updated WQC are ongoing throughout the world. One approach for doing so is to use the biotic ligand model (BLM). The BLM allows metal− organism interactions to be taken into account and, given sitespecific information on water chemistry, to evaluate the dissolved metal concentration associated with a critical level of metal accumulation that is toxic to an organism. The BLM serves as a powerful tool for predicting metal toxicity because it accounts for the concurrent influences of several environmental factors that alter site-specific metal bioavailability to an organism. The influence of water chemistry on metal bioavailability and effects has been reflected in updated regulations in several countries. For example, the U.S. Environmental Protection Agency (EPA) has already adopted a BLM-based WQC for copper. 4 The copper-BLM has been applied to several organisms at different trophic levels. Incorporation of the copper-BLM into EPA’s copper-WQC is based on an acute toxicity BLM. The European Union (EU) has launched a European Union Water Framework Directive. WQC for copper and other metals that have been developed for use within this regulatory framework are typically based on site-specific effect levels that are evaluated by means of chronic BLMs. To date, the BLM has not been widely used in WQC research in China, and only a few studies have attempted to use BLMs to predict metal toxicity in surface waters. Therefore, it is necessary for Chinese scientists to begin to apply currently available BLMs for metals to Chinese waters and to conduct the research that will be needed to implement updated WQC for metals, especially for nickel, copper and zinc, over concentration ranges that reflect water quality characteristics of Chinese waters. There are several reasons why it will be a great challenge to apply BLMs to Chinese waters. First, the physicochemical properties of Chinese surface waters are somewhat unique. As one example, eutrophication is a serious problem in some inland lakes and rivers, such as Lake Taihu, which means concentrations of dissolved organic carbon (DOC) and other parameters will likely be elevated. There are also other regional differences in water chemistry (e.g., pH and hardness), and these geochemical boundaries need to be considered when using the BLM as well. Given the relatively “clean”, less eutrophic characteristics of EU and U.S. freshwaters, it must be determined if BLM parameter values evaluated for concentration ranges of environmental constituents in those settings

Questions about the American Academy of Microbiology Report on Clean Water

The National Water Research Institute's January 9, 2008 Newsletter carried a reference to the report American Academy of Microbiology report “Clean Water: What Is Acceptable Microbial Risk?” (http://www.asm.org/ASM/files/ccLibraryFiles/Filename/000000003520/Clean%20Water%20Small.pdf). I looked this report over and noted some areas that lead to questions. I would appreciate some considered response to the following. I saw nothing on the issues related to transferring antibiotic (antimicrobial) resistance, although there was some discussion of virulence transfer. Thus at least there is the opening to discuss genetic transfer a bit further. I sit on a WERF/EPA panel looking at risk assessments and that group also is thin on looking at the issue of resistance. Both Joan Rose and Amy Pruden sit on this panel. Both note deficiencies in current water quality standards.

The Role of Receiving Water Models in CSO Long-Term Control Plan Decision-Making and Water Quality Standard Revisions

The Role of Receiving Water Models in CSO Long-Term Control Plan Decision-Making and Water Quality Standard RevisionsMany communities have or are developing Long-Term Control Plans (LTCPs) to address their combined sewer overflows (CSOs). Often, however, the most cost-effective strategy for controlling CSOs will still result in occasional violations of current water quality standards. Many states have provided relief to CSO communities through mechanisms that temporarily modify the designated use of the water...Author(s)Carrie TurnerAdrienne NemuraSourceProceedings of the Water Environment FederationSubjectSession 112: Featured Session – Addressing Water Quality Standards in Long- Term Control Plans or How to Stop Worrying and Love the UAA ProcessDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2008ISSN1938-6478SICI1938-6478(20080101)2008:7L.8269;1-DOI10.2175/193864708790893891Volume / Issue2008 / 7Content sourceWEFTECFirst / last page(s)8269 - 8289Copyright2008Word count165

Integrating sentinel watershed-systems into the monitoring and assessment of Minnesota’s (USA) waters quality

Section 303(d) of the Clean Water Act requires States and Tribes to list waters not meeting water quality standards. A total maximum daily load must be prepared for waters identified as impaired with respect to water quality standards. Historically, the management of pollution in Minnesota has been focused on point-source regulation. Regulatory effort in Minnesota has improved water quality over the last three decades. Non-point source pollution has become the largest driver of conventional 303(d) listings in the 21st century. Conventional pollutants, i.e., organic, sediment and nutrient imbalances can be identified with poor land use management practices. However, the cause and effect relationship can be elusive because of natural watershed-system influences that vary with scale. Elucidation is complex because the current water quality standards in Minnesota were designed to work best with water quality permits to control point sources of pollution. This paper presents a sentinel watershed-systems approach (SWSA) to the monitoring and assessment of Minnesota waterbodies. SWSA integrates physical, chemical, and biological data over space and time using advanced technologies at selected small watersheds across Minnesota to potentially improve understanding of natural and anthropogenic watershed processes and the management of point and non-point sources of pollution. Long-term, state-of-the-art monitoring and assessment is needed to advance and improve water quality standards. Advanced water quality or ecologically-based standards that integrate physical, chemical, and biological numeric criteria offer the potential to better understand, manage, protect, and restore Minnesota's waterbodies.

A review of technologies for rapid detection of bacteria in recreational waters

Monitoring of recreational beaches for fecal indicator bacteria is currently performed using culture-based technology that can require more than a day for laboratory analysis, during which time swimmers are at risk. Here we review new methods that have the potential to reduce the measurement period to less than an hour. These methods generally involve two steps. The first is target capture, in which the microbial group of interest (or some molecular/chemical/or biochemical signature of the group) is removed, tagged or amplified to differentiate it from the remaining material in the sample. We discuss three classes of capture methods: 1) Surface and whole-cell recognition methods, including immunoassay techniques and molecule-specific probes; 2) Nucleic acid methods, including polymerase chain reaction (PCR), quantitative PCR (Q-PCR), nucleic acid sequence based amplification (NASBA) and microarrays; and 3) Enzyme/substrate methods utilizing chromogenic or fluorogenic substrates. The second step is detection, in which optical, electrochemical or piezoelectric technologies are used to quantify the captured, tagged or amplified material. The biggest technological hurdle for all of these methods is sensitivity, as EPA's recommended bathing water standard is less than one cell per ml and most detection technologies measure sample volumes less than 1 ml. This challenge is being overcome through addition of preconcentration or enrichment steps, which have the potential to boost sensitivity without the need to develop new detector technology. The second hurdle is demonstrating a relationship to health risk, since most new methods are based on measuring cell structure without assessing viability and may not relate to current water quality standards that were developed in epidemiology studies using culture-based methods. Enzyme/substrate methods may be the first rapid methods adopted because they are based on the same capture technology as currently-approved EPA methods and their relationship to health risk can be established by demonstrating equivalency to existing procedures. Demonstration of equivalency may also be possible for some surface and whole-cell recognition methods that capture bacteria in a potentially viable state. Nucleic acid technologies are the most versatile, but measure nonviable structure and will require inclusion in epidemiological studies to link their measurement with health risk.

Quality and Quantity of Suspended Particles in Rivers: Continent-Scale Patterns in the United States

Suspended solids or sediments can be pollutants in rivers, but they are also an important component of lotic food webs. Suspended sediment data for rivers were obtained from a United States-wide water quality database for 622 stations. Data for particulate nitrogen, suspended carbon, discharge, watershed area, land use, and population were also used. Stations were classified by United States Environmental Protection Agency ecoregions to assess relationships between terrestrial habitats and the quality and quantity of total suspended solids (TSS). Results indicate that nephelometric determinations of mean turbidity can be used to estimate mean suspended sediment values to within an order of magnitude (r(2) = 0.89). Water quality is often considered impaired above 80 mg TSS L(-1), and 35% of the stations examined during this study had mean values exceeding this level. Forested systems had substantially lower TSS and somewhat higher carbon-to-nitrogen ratios of suspended materials. The correlation between TSS and discharge was moderately well described by an exponential relationship, with the power of the exponent indicating potential acute sediment events in rivers. Mean sediment values and power of the exponent varied significantly with ecoregion, but TSS values were also influenced by land use practices and geomorphological characteristics. Results confirm that, based on current water quality standards, excessive suspended solids impair numerous rivers in the United States.

Combined effects of copper and ultraviolet radiation on a microscopic green alga in natural soft lake waters of varying dissolved organic carbon content

Selenastrum capricornutum was grown in two lake waters of differing dissolved organic carbon content (1.8 vs. 9.1 mg DOC l −1) to determine the responses of population dynamics and photosynthesis to Cu, and to assess the modifying effects of varying ultraviolet radiation (UVR) exposure. In the absence of UVR, the mean EC 50 for Cu effect on population growth rate was 2.3–2.6 μg l −1 in the low DOC water and 17.4–26.2 μg l −1 in the high DOC water. The variable chlorophyll a fluorescence ratio, F v/ F m, decreased approximately in parallel with the diminished growth rates. Exposure of the higher DOC lake water to full spectrum artificial radiation caused an increase of Cu 2+ concentration, compared to samples held in darkness or in photosynthetically active radiation (PAR) only. Full spectrum exposures also resulted in a lower (although not significantly so) EC 50 for Cu effect on growth rate, consistent with response to the moderately elevated Cu 2+ concentration. Cu 2+ concentration was unaffected by radiation exposure in the low DOC water, and EC 50s for growth were also unaffected except in the most severe UVR treatment, which was >40% inhibited even in the absence of added Cu. Using F v/ F m as an end-point, there was no evidence of interactions between UVR and Cu under the relatively low PAR exposures used here. Algal growth and photosynthesis was extremely sensitive to Cu in these soft lake waters, with EC 50s close to current water quality standards in the low DOC water.

A LONG‐TERM, WATERSHED‐SCALE, EVALUATION OF THE IMPACTS OF ANIMAL WASTE BMPs ON INDICATOR BACTERIA CONCENTRATIONS1

ABSTRACT: Driven by increasing concerns about bacterial pollution from agricultural sources, states such as Virginia have initiated cost sharing programs that encourage the use of animal waste best management practices (BMPs) to control this pollution. Although a few studies have shown that waste management BMPs are effective at the field scale, their effectiveness at the watershed scale and over the long term is unknown. The focus of this research was to evaluate the effectiveness of BMPs in reducing bacterial pollution at the watershed scale and over the long term. To accomplish this goal, a 1,163 ha watershed located in the Piedmont region of Virginia was monitored over a ten‐year period. Fecal coliforms (FC) and fecal streptococci (FS) were measured as indicators of bacterial pollution. A pre‐BMP versus post‐BMP design was adopted. Major BMPs implemented were manure storage facilities, stream fencing, water troughs, and nutrient management. Seasonal Kendall trend analysis revealed a significant decreasing trend during the post‐BMP period for FC concentrations at the watershed outlet, but not at the subwatershed level. Implementation of BMPs also resulted in a significant reduction in the geometric mean of FS concentrations. FC concentrations in streamflow at the watershed outlet exceeded the Virginia primary standard 86 and 74 percent of the time during pre‐BMP and post‐BMP periods, respectively. Corresponding exceedances for the secondary standard were 50 and 41 percent. Violations decreased only slightly during the post‐BMP period. The findings of this study suggest that although BMP implementation can be expected to accomplish some improvement in water quality, BMP implementation alone may not ensure compliance with current water quality standards.