Potential Water Contamination Research Articles

Cost Effective and Natural Plant Based Coagulant for Removal of Chloride from Potable Water

In present study, water quality was assessed by collecting ten water samples in and around Tiruppur city of India. The physico-chemical characterisation of the water samples were analyzed using standard protocols. The samples with higher chloride content (3106 mg/L) was found in Ganapathy Palayam sample, the value was higher than the BIS prescribed limit. The sample was subjected to treatment with various dosages of the phyto coagulating agent Tamarindus indica L. seed powder and its polysaccharide. The maximum 51 % of chloride reduction was obtained with 0.3 g of seed polysaccharide, and it was taken as optimum dosage. The raw seed removed 47 % of chloride by the dosage 0.4 g. The seed powder was characterized by GC-MS and FT-IR analysis. The GC-MS chromatogram showed the presence of various phytocompounds such as lupanine, cyclopropane octanoic acid, ascorbic acid, octadecanoic acid in the plants. The functional groups found in the seed powder were characterized by FTIR analysis. The evaluated results confirmed the contamination of potable water in Tiruppur city by the dyeing industries located near the water sources. The present work concluded that tamarind seed coagulants are efficient, eco-friendly, low-cost and easily available material, which could be used for the treatment of potable water.

Norovirus outbreak in a natural playground: A One Health approach.

Norovirus constitutes the most frequently identified infectious cause of disease outbreaks associated with untreated recreational water. When investigating outbreaks related to surface water, a One Health approach is insightful. Historically, there has been a focus on potential contamination of recreational water by bird droppings and a recent publication demonstrating human noroviruses in bird faeces suggested this should be investigated in future water‐related norovirus outbreaks. Here, we describe a One Health approach investigating a norovirus outbreak in a natural playground. On social media, a large amount of waterfowl were reported to defecate near these playground premises leading to speculations about their potential involvement. Surface water, as well as human and bird faecal specimens, was tested for human noroviruses. Norovirus was found to be the most likely cause of the outbreak but there was no evidence for transmission via waterfowl. Cases had become known on social media prior to notification to the public health service underscoring the potential of online media as an early warning system. In view of known risk factors, advice was given for future outbreak investigations and natural playground design.

Comment on “ferroelectricity-free lead halide perovskites” by A. Gómez, Q. Wang, A. R. Goñi, M. Campoy-Quiles and A. Abate, Energy Environ. Sci., 2019, 12, 2537

This comment analyzes pitfalls when investigating piezoresponse and ferroelectricity in organic-metal halide perovskite thin films.

Cuprous Oxide- or Copper-Coated Jute Stick Pieces at an Air-Water Interface for Prevention of Aerial Contamination in Potable Water.

Cuprous oxide and copper have been synthesized via the solvothermal process using basic copper carbonate as the source of copper. Pure Cu2O or Cu could be afforded by simply varying the solvent while keeping the temperature and time constant. In this study, copper-based materials were coated on jute stick pieces (JSP) in situ. Cu2O-coated JSP (Cu2O-JSP) and Cu-coated JSP (Cu-JSP) were characterized by powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). Cu2O-JSP and Cu-JSP were found to be active against Escherichia coli NCIM 2931 (Gram-negative bacteria) and Staphylococcus aureus (Gram-positive bacteria). The antibacterial nature of the material and the buoyant nature of Cu2O-JSP and Cu-JSP were exploited to develop beaded necklace-like strands that could be floated on potable water to effectively prevent aerial contamination. Leaching of copper from both Cu2O-JSP and Cu-JSP into water was found to be below the permissible limit for copper in drinking water.

The application of rapid handheld FTIR petroleum hydrocarbon-contaminant measurement with transport models for site assessment: A case study

Conventional contaminated site assessment requires sophisticated sampling and laboratory analyses, which are costly and time consuming. There is a trend for soil analyses to shift from complex laboratory procedures to rapid, simple and non-destructive spectroscopic methods that can be used in the field. Handheld Fourier Transform Infrared (FTIR) spectroscopy has the advantage of providing information for rapid in situ site characterisation. To apply the infrared (IR) spectral application for petroleum hydrocarbon (PH) contamination site investigation, the coherent bands at locations from 3000 to 2800 cm−1 represent carbon (C) – hydrogen (H) bonding for long-chain alkanes due to –C–H stretching vibrations. The areas of the coherent bands at these locations can be used to quantify the total petroleum hydrocarbon (TPH) concentrations in soils. With additional spectral data from IR spectroscopy there is potential for predicting soil texture and water content, which are the basic inputs for modelling the migration of PH at contaminated sites. This study demonstrates the innovative coupling of spectral analytical models and a handheld FTIR instrument, with a soil erosion model, the Revised Universal Soil Loss Equation (RUSLE), and the Hydrus hydrological model. The integration of these models were used to investigate the potential downstream water and groundwater contamination risks from the migration of PH at a PH-contaminated site.

1227. Replacement and Rerouting of Pipes to Remediate Intractable Contamination of Potable Water Fixtures in a Pair of ICU Rooms

Background“Green” construction approaches may place hospitals at risk for long-term contamination of potable water, presenting hazards for immunosuppressed patients. Remediation may be needed to manage these unanticipated consequences. An indolent, 11-year cluster of Sphingomonas koreensis infections at the NIH Clinical Center was traced to potable water. During the investigation, 4 sinks in 2 ICU rooms were found to have intractable contamination. Despite replacement of sink fixtures, faucet swabs and water continued to grow S. koreensis, and mean free chlorine residual (FCR) from the sinks was 0.27 mg/L (goal > 0.5). We undertook a major project to replace and reroute sections of pipes leading to the sinks (Figures 1 and 2).MethodsHot and cold water pipes were removed from the sinks to the supply pipes and replaced. Pipes were rerouted so that hot and cold water supplying the sinks returned in a loop to the domestic hot water heater to eliminate 10-meter drop-down sections of dead-leg pipe. Automatic faucets were replaced with manual faucets. Faucet biofilm was swabbed and cultured monthly for S. koreensis. Environmental samples were cultured on sheep blood agar for 5 days. Yellow colonies were subcultured and identified by MALDI-TOF MS (Bruker).ResultsDemolition of the wall behind the sinks revealed hot and cold water piping containing stagnant water. Water pooled in cold water pipe had heavy growth of S. koreensis; water from the hot water pipe could not be collected. Hot and cold water FCR for the sinks after piping changes averaged 0.74 and 1.07 mg/L, respectively, compared with 0.27 mg/L simultaneously from automated faucets in unmodified ICU rooms. Faucet cultures were negative for S. koreensis after replumbing, and have remained negative for >6 months.ConclusionNew hospital construction strategies appear to increase potable water contamination risks; novel remediation approaches are needed. Replacing contaminated water pipes and rerouting pipes to minimize stagnation eradicated longstanding contamination of 2 ICU sinks. Although the experiment was conducted on a small scale, it demonstrates that plumbing flaws that jeopardize patient safety can be corrected through multidisciplinary collaboration and creative plumbing strategies. Disclosures All authors: No reported disclosures.

2451. Hospital-acquired Legionella Pneumonia Outbreak at an Academic Medical Center. A Case–control Study of Risk Factors

BackgroundAn outbreak of hospital-acquired Legionella pneumonia, associated with potable water contamination, occurred at our university hospital in November of 2018, despite a longstanding copper-silver ionization system. We conducted a case–control study to examine risk factors for Legionella pneumonia.MethodsWe matched controls to cases by dates of admission, hospital ward, and admitting service, in a 4:1 ratio. We reviewed patient charts for potential risk factors and exposures, and summarized demographic information using descriptive analyses. Univariate and multiple logistic regression analyses were also performed. We used pulsed-field gel electrophoresis for molecular typing of isolates from patient respiratory samples and hospital water samples.ResultsWe identified 13 cases of nosocomial legionella pneumonia over a one-month period (Figure 1), with 8 males, 5 females, and a mean age of 63 years. The average time to diagnosis was 19 days following admission. Six patients were transplant recipients – two had solid organ, and six had bone marrow transplant. Urinary Legionella antigen was positive in all cases. Table 1 shows predictors for Legionella pneumonia in univariate analyses. Current smoking (OR = 7.5, 95% CI [1.11 – 50.84], p = 0.03], pre-admission steroid prescription (OR = 6.5, 95% CI [1.65 – 26.20], p = 0.008], documentation of shower (OR = 6.2, 95% CI [1.54 – 25.82], p = 0.01], and number of showers prior to hyper-chlorination (OR = 1.45, 95% CI [1.03 – 2.04], p = 0.03] were significant risk factors on univariate analysis. The multiple regression model was also significant (P < 0.001) with all of the above-identified predictors (Table 2). Molecular typing found Legionella strains from patient respiratory samples and water samples to be identical. Multiple interventions, including restriction of showering, hyper-chlorination, and optimization of water flow through the copper-silver ionization system were implemented, and were successful in mitigating the outbreak.ConclusionWe found showering to be a modifiable risk factor for Legionella pneumonia in this outbreak. Interventions to reduce this risk might include point of use filters in showers in high-risk populations. Disclosures All authors: No reported disclosures.

Syndromic Surveillance of Communicable Diseases in Mobile Clinics During the Arbaeenia Mass Gathering in Wassit Governorate, Iraq, in 2014: Cross-Sectional Study.

BackgroundArbaeenia is the largest religious mass gathering organized annually in Karbala city, Iraq, and is attended by 8-14 million people. Outbreaks of communicable diseases are a significant risk due to overcrowding and potential food and water contamination. Syndromic surveillance is often used for rapid detection and response to disease outbreaks.ObjectiveThis study was conducted to identify the main communicable diseases syndromes among pilgrims during the Arbaeenia mass gathering in Wassit governorate, Iraq, in 2014.MethodsThis cross-sectional study was conducted in the 40 mobile clinics established within Wassit governorates along the road to Karbala during the Arbaeenia mass gathering. Six communicable disease syndromes were selected: acute watery diarrhea, bloody diarrhea, fever and cough, vomiting with or without diarrhea, fever and bleeding tendency, and fever and rash. A simple questionnaire was used to directly gather basic demographics and the syndromic diagnosis from the attendees.ResultsA total of 87,865 patients attended the clinics during the 10-day period, with an average of 219 patients/clinic/day. Approximately 5% (3999) of the attendees had communicable diseases syndromes: of these, 1693 (42%) had fever and cough, 1144 (29%) had acute diarrhea, 1062 (27%) presented with vomiting with/without diarrhea, and 100 (2%) had bloody diarrhea. The distribution of the syndromes did not vary by age or gender. Stool specimen cultures for Vibrio cholerae performed for 120 patients with acute diarrhea were all negative.ConclusionsSyndromic surveillance was useful in determining the main communicable diseases encountered during the mass gathering. Expansion of this surveillance to other governorates and the use of mobile technology can help in timely detection and response to communicable disease outbreaks.

Polyamide-Laccase Nanofiber Membrane for Degradation of Endocrine-Disrupting Bisphenol A, 17α-ethinylestradiol, and Triclosan.

Contamination of potable water by endocrine disrupting chemicals (EDCs) is a growing problem worldwide. One of the possible treatments is the utilization of laccase enzyme catalyzing oxidation of phenolic structures of EDC when anchored in a polymeric nanofiber membrane. Previous studies failed to develop a membrane with a sufficiently active enzyme, or the immobilization process was too complicated and time-consuming. Here, we established an elegant method for immobilizing Trametes versicolor laccase onto polyamide 6 nanofibers (PA6-laccase) via adsorption and glutaraldehyde crosslinking, promoting high enzyme activity and easier applicability in water treatment technology. This simple and inexpensive immobilization ensures both repeated use, with over 88% of initial activity retained after five ABTS catalytic cycles, and enhanced storage stability. PA6-laccase was highly effective in degrading a 50-µM EDC mixture, with only 7% of bisphenol A, 2% of 17α-ethinylestradiol, and 30% of triclosan remaining after a 24-h catalytic process. The PA6-laccase membrane can lead to the improvement of novel technologies for controlling of EDC contamination in potable water.

Alkali earth ratios differentiate conventional and unconventional hydrocarbon brine contamination

The large increase in unconventional shale gas extraction has raised concerns about potential water contamination from leaks and spills. Shale gas produced water is challenging to detect in areas impacted by legacy contamination, particularly from conventional sources. Previous studies have proposed combinations of Br, SO4, Ba, Cl, and other more specialized stable isotope systems to delineate shale gas produced water from 1) non-impacted waters and 2) other sources of water contamination. In general, the efforts that rely on relatively simple chemistry do not allow differentiation between conventional and unconventional brine chemistry. We examined variations in Ca/Mg and Ca/Sr ratios that seem to arise from variation in temperature with depth, to differentiate among conventional brines, unconventional brines, and non-impacted waters. This approach was applied to four sedimentary basins in the USGS produced water database: Williston, Michigan, Appalachian, and the Green River basin. In addition, the utility of the system was demonstrated with field samples taken during periods of known unconventional brine releases to surface waters. The Ca/Mg and Ca/Sr ratios allow distinction among these three water types in all basins, suggesting a relatively simple and direct way to evaluate water chemistries in landscapes dominated by unconventional shale gas extraction.

Occurrence of Cryptosporidium and Giardia in potable water sources in Chandigarh, Northern India

AbstractContamination with Cryptosporidium and Giardia from drinking water sources in a city in Northern India was assessed. A protocol modified from a standard ISO protocol, which includes filtration, concentration, separation and detection steps, was tested and showed comparable recovery efficiencies (Giardia mean = 77.4%, Cryptosporidium mean = 61.8% from the modified protocol, compared with Giardia mean = 61.6%, Cryptosporidium mean = 69% from the ISO protocol) at a substantial cost reduction. This protocol was used for analysing 71 samples of potable water from different areas of Chandigarh, where sampling locations were divided into groups according to the population density, which also partially equates with the level of infrastructure. Samples were collected during (n = 29) and outside the monsoon season (n = 42). Of all samples analysed, 16 (22.5%) were Cryptosporidium- and/or Giardia-positive. Parasites per sample were low (1–10 (oo)cysts per 10 L), although one sample contained large numbers of Giardia cysts (&gt;1,000). Polymerase chain reaction analyses on the small subunit ribosomal ribonucleic acid (SSU rRNA), triose-phosphate isomerase (tpi), glutamate dehydrogenase (gdh) and beta-giardin (bg) gene sequences on Giardia-positive samples and SSU rRNA on Cryptosporidium-positive samples tended to be unsuccessful, although Giardia cysts of Assemblages B and C were identified. No association with the season was detected, but an association with the location of water supply was identified. Samples from areas with the lowest infrastructure were not associated with higher levels of contamination, but samples from the middle level were significantly more likely to be contaminated than those from the highest level of infrastructure. Results indicate that even in a city with a well-developed infrastructure, the contamination of potable water with protozoan parasites remains a public health risk.

Effect of flavonoids isolated from Tridax procumbens on the growth and toxin production of Microcystis aeruginos

The excessive proliferation of toxin producing cyanobacteria constitutes a significant health risk to the environment and humans. This is due to the contamination of potable water and accumulation of cyanotoxins in plant and animal tissues. As a means of controlling bloom forming cyanobacteria, secondary metabolites with pro-oxidative activities from plants are used to treat water bodies contaminated with cyanobacterial blooms and their associated toxins. The objective of the present study was to evaluate the mechanism of action of extract, fractions and isolated flavonoids of Tridax procumbens L. on Microcystis aeruginosa (Kützing) Kützing. by monitoring changes in growth, oxidative stress, antioxidant response, and cyanatoxin microcystins (MCs) production. The extract, fraction 3 and the isolated flavonoids significantly reduced the cell density of the cyanobacterium. Furthermore, the extract and fraction 3 increased the production of reactive oxygen species, induced lipid peroxidation, and altered antioxidant enzyme activities of M. aeruginosa. The total MCs content of the cyanobacterium was negatively affected by the presence of the extract, fractions and isolated flavonoids. The present study show that T. procumbens has secondary metabolites that are capable of interfering with the physiology and microcystins production of M. aeruginosa. These characteristics are promising for the control of this noxious cyanobacterium in aquatic ecosystems.

Catalytic Converters for Water Treatment.

Fresh water demand is driven by human consumption, agricultural irrigation, and industrial usage and continues to increase along with the global population. Improved methods to inexpensively and sustainably clean water unfit for human consumption are desired, particularly at remote or rural locations. Heterogeneous catalysts offer the opportunity to directly convert toxic molecules in water to nontoxic products. Heterogeneous catalytic reaction processes may bring to mind large-scale industrial production of chemicals, but they can also be used at the small scale, like catalytic converters used in cars to break down gaseous pollutants from fuel combustion. Catalytic processes may be a competitive alternative to conventional water treatment technologies. They have much faster kinetics and are less operationally sensitive than current bioremediation-based methods. Unlike other conventional water treatment technologies (i.e., ion exchange, reverse osmosis, activated carbon filtration), they do not transfer contaminants into separate, more concentrated waste streams. In this Account, we review our efforts on the development of heterogeneous catalysts as advanced reduction technologies to treat toxic water contaminants such as chlorinated organics and nitrates. Fundamental understanding of the underlying chemistry of catalytic materials can inform the design of superior catalytic materials. We discuss the impact of the catalytic structure (i.e., the arrangement of metal atoms on the catalyst surface) on the catalyst activity and selectivity for these aqueous reactions. To explore these aspects, we used model metal-on-metal nanoparticle catalysts along with state-of-the-art in situ spectroscopic techniques and density functional theory calculations to deduce the catalyst surface structure and how it affects the reaction pathways and hence the activity and selectivity. We also discuss recent developments in photocatalysis and electrocatalysis for the treatment of nitrates, touching on fundamentals and surface reaction mechanisms. Finally, we note that despite over 20 years of growing research into heterogeneous catalytic systems for water contaminants, only a few pilot-scale studies have been conducted, with no large-scale implementation to date. We conceive of modular, on- or off-grid catalytic units that treat drinking water at the household tap, at a community well, or for larger-scale reuse of agricultural runoff. We discuss how these may be enhanced by combination with photocatalytic or electrocatalytic processes and how these reductive catalytic modules (catalytic converters for water) can be coupled with other modules for the removal of potential water contaminants.

Impact of Fly Ash Placement in an Abandoned Opencast Mine on Surface and Ground Water Quality: A Case Study

We investigated potential contamination of surface and ground water due to placement of fly ash in an abandoned area of an active opencast mine. Leachates from the fly ash and pond ash did not exceed the effluent discharge limits for inland surface water. Even though iron was one of the major components of the ash, it did not exceed 0.3 mg/L in the leachates. Water quality studies carried out at the coal mine indicated that fly ash disposal there, was not affecting the groundwater, but that the water discharged from the active portion of the mine contained high concentrations of total hardness, total dissolved solids (TDS), sulphate, manganese, and iron, exceeding India’s effluent discharge limits. The nearby Ajay River was not contaminated but the confluence point where the mine water met the Ajay River contained high levels of TDS, sulphate, and manganese. Groundwater in the area surrounding the mine was not significantly impacted. Multivariate statistical analysis was carried out to determine the relationships between the different water quality parameters.

Exploration of bacterial contaminants in reservoirs of Palamuru by PCR-DGGE method: household water treatment

Abstract This study is principally aimed at the exploration of the bacterial contaminants that are prevalent in the drinking water of different reservoirs in Mahabubnagar, TS, India, along with cost-effective water treatment using palatable leaves of Mentha piperita. Water samples from three different reservoirs of Palamuru, namely, Ramanpadu reservoir (RPR), Koilsagar reservoir (KSR) and Jurala reservoir (JUR), were collected and bacteriological and chemical parameters were assessed. Colony forming units (CFU) were determined by plate culture method using different media. The bacterial diversity concomitant with the three different reservoirs was examined and compared using a molecular approach coalescing fingerprinting by denaturing gradient gel electrophoresis (DGGE). Overall, 37 16S rDNA sequences were obtained. The sequencing dominant bands validated that the major phylogenetic groups identified by DGGE belonged to Bacillus, Brevibacillus, Exiguobacterium, Gammaproteobacteria, Acinetobacter sp. and some uncultured or unidentified bacteria. At household level, incubation of potable water with pudina leaves decreased the bacterial contamination showing its anti-bacterial effect and proving it to be an easy method to impede bacterial contamination in potable water.

CCS Risk Assessment: Groundwater Contamination Caused by CO2

The potential contamination of underground drinking water (UDW) caused by CO2 leakage is a critical decision input for risk assessment and management decision making. This paper presents an overview of the potential alterations to UDW quality caused by CO2 and the relevant quality guidelines on drinking water. Furthermore, a framework and numerical simulator have been developed to (i) predict and assess the potential consequences of CO2 leakage on the quality of UDW; and (ii) assess the efficiency of groundwater remediation methods and scenarios for various UDW leakage conditions and alterations. The simulator was applied to a Canadian CO2 disposal site to assess the potential consequences of CO2 leakage on groundwater quality. The information, framework, and numerical tool presented here are useful for successful risk assessments and the management of CO2 capture and sequestration in Canadian geological formations.

Cytological Effects of Bleaching Agent (Quneex) on Plant Cells and Plant DNA.

There have been a number of reported drawbacks and efficacy issues regarding the use of bleaching agents in the plant industry. This study was conducted to determine the cytological effects of the bleaching agent (Quneex) on the plant cells and plant DNA using the Allium cepa assay. It was subjected sixteen root meristems of A. cepa to different concentrations of the bleaching agent (0.1, 0.2, 0.3, 0.4 and 0.5%) with different periods of time (6, 12 and 24 h). Recovery was done for 6, 12 and 24 h after exposure. The mitotic index significantly decreased with time and also decreased with increase in the concentration of the bleaching agent. Abnormal chromosomal changes reflecting mutagenesis including stickiness, laggards, bridges, C-metaphase, star-metaphase, binucleation, polyploidy, disturbance and multinucleation were observed in the different concentrations and periods of time. After recovery, a slow increase in the mitotic index was observed. All treatments with or without recovery for 12 and 24 h resulted in reduction in the amount of DNA. Bleaching agents similar to Quneex containing sodium hypochlorite have mutagenic properties that can be potentially hazardous to the environment and also to humans. Thus, there is a need to regulate the use and disposal of such chemicals into the environment particularly to the sewers, to prevent contamination of potable water, plant and biodiverse aquatic animals.

Cerium dioxide and composites for the removal of toxic metal ions

The presence of contaminants in potable water is a cause of worldwide concern. In particular, the presence of metals such as arsenic, lead, cadmium, mercury, chromium can affect human health. There is thus a need for advanced techniques of water decontamination. Adsorbents based on cerium dioxide (CeO2), also named ‘ceria,’ have been used to remove contaminants such as arsenic, fluoride, lead and cadmium. Ceria and composites display high surface area, controlled porosity and morphology, and abundance of functional groups. They have already found usage in many applications including optical, semiconductor and catalysis. Exploiting their attractive features for water treatment would unravel their potential. We review the potential of ceria and its composites for the removal of toxic metal ions from aqueous medium. The article discusses toxic contaminants in water and their impact on human health; the synthesis and adsorptive behavior of ceria-based materials including the role of morphology and surface area on the adsorption capacity, best fit adsorption isotherms, kinetic models, possible mechanisms, regeneration of adsorbents; and future perspectives of using metal oxides such as ceria. The focus of the report is the generation of cost-effective oxides of rare-earth metal, cerium, in their standalone and composite forms for contaminant removal.

Life Cycle Environmental Impact Assessment on Different Modes of Greenhouse Vegetable Production in the North China Plain

Organic agriculture has a higher potential than traditional agriculture to reduce environmental emissions. However, heavy metals in organic manure inevitably exacerbate eco-toxicity. At present, there are few studies on systematically and comprehensively evaluating the effects of different production modes on the environmental impact of vegetable production in the North China Plain (NCP). The objective of this study is to provide a theoretical direction for reducing the negative impact of greenhouse vegetable production. In this study, we used a greenhouse eggplant production (2013-2016) as case study and conducted a field experiment in Quzhou County, Hebei Province, China. The life cycle assessment (LCA) approach was used to analyze and compare the production and environmental impacts of eggplant production under three modes:conventional, integrated, and organic. The results showed that the potential for water contamination, eutrophication, and soil contamination was high among the three modes, ranging from 82.05% to 84.02%, 10.29% to 12.32%, and 2.62% to 3.48%, respectively. This is occurred mainly in the arable farming subsystem and is attributed to the loss of nitrogen (N) and phosphorus (P), pesticide residues, and heavy metals in organic manure. The environmental impact index of the integrated mode is the lowest, with a value of 0.596, which is 30.3% and 6.7% lower than those of the conventional and organic modes. The integrated mode significantly reduces the emission of pollutants from the greenhouse vegetable production in the arable farming subsystem; therefore, it is the best management practice. In the integrated mode, the environmental costs of producing one ton of eggplant are 46.6 J for energy depletion, 81.9 m2 for land occupation, 0.0046 m3 for water depletion, 0.0054 kg (CO2-eq) for global warming, 0.0060 kg (SO2-eq) for acidification, 0.0735 kg (PO4-eq) for aquatic eutrophication, 2.84E-05 kg (1,4-DCB-eq) for human toxicity, 0.4892 kg (1,4-DCB-eq) for aquatic eco-toxicity, and 0.0174 kg (1,4-DCB-eq) for soil eco-toxicity. Optimizing field management measures such as the application of biological pesticides, using high quality organic fertilizer, and improving the efficiency of N and P use, can better control the negative environmental impacts in the life cycle of vegetable production and improve environmental sustainability in the NCP.

Human Health Impact of Cross-Connections in Non-Potable Reuse Systems.

We used quantitative microbial risk assessment (QMRA) to estimate the microbial risks from two contamination pathways in onsite non-potable water systems (ONWS): contamination of potable water by (treated) reclaimed, non-potable water and contamination of reclaimed, non-potable water by wastewater or greywater. A range of system sizes, event durations, fraction of users exposed, and intrusion dilutions were considered (chlorine residual disinfection was not included). The predicted annual microbial infection risk from domestic, non-potable reuse remained below the selected benchmark given isolated, short-duration intrusion (i.e., 5-day) events of reclaimed water in potable water. Whereas, intrusions of wastewater into reclaimed, non-potable water resulted in unacceptable annual risk without large dilutions or pathogen inactivation. We predicted that 1 user out of 10,000 could be exposed to a 5-day contamination event of undiluted wastewater in the reclaimed, non-potable water system each year to meet the annual benchmark risk of 10−4 infections per person per year; whereas, 1 user out of 1000 could be exposed to a 5-day contamination event of undiluted reclaimed water in the potable water each year. Overall, the predicted annual risks support the use of previously derived non-potable reuse treatment requirements for a variety of ONWS sizes and support the prioritization of protective measures to prevent the intrusion of wastewater into domestic ONWS.