A Critical Review on the Factors that Influence Opportunistic Premise Plumbing Pathogens: From Building Entry to Fixtures in Residences.

Residential buildings provide unique conditions for opportunistic premise plumbing pathogen (OPPP) exposure via aerosolized water droplets produced by showerheads, faucets, and tubs. The objective of this review was to critically evaluate the existing literature that assessed the impact of potentially enhancing conditions to OPPP occurrence associated with residential plumbing and to point out knowledge gaps. Comprehensive studies on the topic were found to be lacking. Major knowledge gaps identified include the assessment of OPPP growth in the residential plumbing, from building entry to fixtures, and evaluation of the extent of the impact of typical residential plumbing design (e.g., trunk and branch and manifold), components (e.g., valves and fixtures), water heater types and temperature setting of operation, and common pipe materials (copper, PEX, and PVC/CPVC). In addition, impacts of the current plumbing code requirements on OPPP responses have not been assessed by any study and a lack of guidelines for OPPP risk management in residences was identified. Finally, the research required to expand knowledge on OPPP amplification in residences was discussed.

Residential Water Softeners Release Carbon, Consume Chlorine, and Require Remediation after Hydrocarbon Contamination.

Water quality impacts of new ion exchange point-of-entry residential softeners and their ability to be decontaminated following hydrocarbon exposure were investigated. During startup, significant amounts of total sulfur (445 ± 815 mg/L) and total organic carbon (937 ± 119 mg/L) were released into the drinking water that flowed through the softeners. Particulate organic carbon was released until the third regeneration cycle, and resin may also have been released. After one week of device use, softeners continued to cause organic carbon levels to be four to five times greater than background levels. Leached materials from the ion-exchange resin contributed to chlorine decay. When resins were exposed to hydrocarbon-contaminated water, they sorbed benzene, toluene, ethylbenzene, and xylenes (BTEX) and then desorbed the contaminants into drinking water during a 15 day flushing decontamination period. On day 15, benzene exceeded the federal drinking water limit for two of the four resins. The aged resin contributed to the greatest chlorine decay rates and sorbed and then retained the least amount of BTEX. Scale and biofilm on the aged resin likely prompted disinfectant reactivity and inhibited BTEX diffusion into the resin. Study results show that softeners exposed to hydrocarbon-contaminated water may need to be repeatedly flushed to remove BTEX contamination or be replaced. Additional work is recommended to better understand softener impacts on drinking water quality.

Bystander chemical exposures and injuries associated with nearby plastic sewer pipe manufacture: public health practice and lessons.

Cured-in-place pipes (CIPPs) are plastic liners manufactured inside existing damaged sanitary sewer, storm sewer, and water pipes that extend the service life of host pipes. This process often is conducted in neighborhoods and near roadways. Before, during, and after plastic manufacture, waste materials that include volatile materials are released into the air. Emissions from this manufacturing process can affect outdoor air quality and indoor air quality for buildings connected to the sewer system. We identified key issues and solicited stakeholder feedback to estimate and manage public health risks of CIPP-generated chemical air pollution. A work group representing 13 U.S. agencies and public health associations provided feedback and prioritized public health issues for action. To mitigate potential public and occupational health risks, additional testing and public health educational efforts were recommended. An improved understanding of CIPP chemical exposure pathways, as well as stakeholder needs and interests, is essential.

Impacts of Municipal Water-Rainwater Source Transitions on Microbial and Chemical Water Quality Dynamics at the Tap.

When rainwater harvesting is utilized as an alternative water resource in buildings, a combination of municipal water and rainwater is typically required to meet water demands. Altering source water chemistry can disrupt pipe scale and biofilm and negatively impact water quality at the distribution level. Still, it is unknown if similar reactions occur within building plumbing following a transition in source water quality. The goal of this study was to investigate changes in water chemistry and microbiology at a green building following a transition between municipal water and rainwater. We monitored water chemistry (metals, alkalinity, and disinfectant byproducts) and microbiology (total cell counts, plate counts, and opportunistic pathogen gene markers) throughout two source water transitions. Several constituents including alkalinity and disinfectant byproducts served as indicators of municipal water remaining in the system since the rainwater source does not contain these constituents. In the treated rainwater, microbial proliferation and Legionella spp. gene copy numbers were often three logs higher than those in municipal water. Because of differences in source water chemistry, rainwater and municipal water uniquely interacted with building plumbing and generated distinctively different drinking water chemical and microbial quality profiles.

In vitro toxicity assessment of emitted materials collected during the manufacture of water pipe plastic linings.

Objectives: US water infrastructure is in need of widespread repair due to age-related deterioration. Currently, the cured-in-place (CIPP) procedure is the most common method for water pipe repair. This method involves the on-site manufacture of a new polymer composite plastic liner within the damaged pipe. The CIPP process can release materials resulting in occupational and public health concerns. To understand hazards associated with CIPP-related emission exposures, an in vitro toxicity assessment was performed. Materials and Methods: Mouse alveolar epithelial and alveolar macrophage cell lines and condensates collected at 3 worksites utilizing styrene-based resins were utilized for evaluations. All condensate samples were normalized based on the major emission component, styrene. Further, a styrene-only exposure group was used as a control to determine mixture related toxicity. Results: Cytotoxicity differences were observed between worksite samples, with the CIPP worksite 4 sample inducing the most cell death. A proteomic evaluation was performed, which demonstrated styrene-, worksite-, and cell-specific alterations. This examination of protein expression changes determined potential biomarkers of exposure including transglutaminase 2, advillin, collagen type 1, perilipin-2, and others. Pathway analysis of exposure-induced proteomic alterations identified MYC and p53 to be regulators of cellular responses. Protein changes were also related to pathways involved in cell damage, immune response, and cancer. Conclusions: Together these findings demonstrate potential risks associated with the CIPP procedure as well as variations between worksites regarding emissions and toxicity. Our evaluation identified biological pathways that require a future evaluation and also demonstrates that exposure assessment of CIPP worksites should examine multiple chemical components beyond styrene, as many cellular responses were styrene-independent.

Analysis of building plumbing system flushing practices and communications.

Drinking water distribution system contamination incidents can prompt public agencies and drinking water utilities to issue do-not-drink and do-not-use advisories. After the contaminant is cleared from distribution mains, consumers are often directed to flush their plumbing. However, little validated guidance and few evaluated communications strategies are available on using flushing to decontaminate building water systems. Additionally, limited data support the effectiveness of current practices and recommendations. In this study, expert elicitation was used to assess existing flushing guidance and develop validated flushing guidance and communications for single-family residences. The resulting guidance recommends progressively opening all cold-water taps from the closest to point of entry to the furthest and allowing the water to run for at least 20 minutes. Hot-water taps should be opened progressively and run for at least 75 minutes. The guidance language and format conformed to grade-level and readability scores within recommended health communication ranges. The readability of eight other flushing guidance documents was also evaluated for contamination incidents from 2008-2015. Seven were written at a 10th-12th grade level, above the 6th-7th grade level recommended for health communications.

Impact of dispersant on early life stages of the water flea Daphnia magna and the eastern oyster Crassostrea virginica.

In response to the 2010 Deepwater Horizon oil spill, over 1 million gallons of dispersant were applied in Gulf of Mexico offshore waters; Corexit 9500 was the most applied dispersant. The impact on organisms in nearshore and freshwaters has received little scrutiny. Acute 48 h toxicity of Corexit 9500 and a new hyperbranched polyethylenimine (HPEI) dispersant-like compound were evaluated for the freshwater indicator organism, Daphnia magna and for larval and early spat stages of the Eastern oyster, Crassostrea virginica. For D. magna, Corexit 9500 demonstrated toxicity (EC50 of 0.14 [0.13, 0.15] ppm) similar to the 10-kDa HPEI (EC50 of 0.16 [0.12, 0.19] ppm). HPEI toxicity increased as a function of molecular weight (1.2 to 750 kDa). The 10 kDa size HPEI was further investigated because it dispersed crude oil with equal effectiveness as Corexit. For Corexit, 100% oyster mortality was detected for the ≤0.2-mm size classes and mortality >50% for the 0.3- and 0.7-mm size classes at the two greatest concentrations (25 and 50 ppm). HPEI (10 kDa) exhibited low mortality rates (<30%) for all concentrations for all oyster size classes except the 0.1-mm class. Although mortality rates for this size class were up to 60%, mortality was still less than the mortality caused by Corexit 9500. The low toxicity of HPEI polymers for C. virginica in comparison with Corexit 9500 suggests that HPEI polymers warrant further study.

Enabling Science Support for Better Decision-Making when Responding to Chemical Spills.

Chemical spills and accidents contaminate the environment and disrupt societies and economies around the globe. In the United States there were approximately 172,000 chemical spills that affected US waterbodies from 2004 to 2014. More than 8000 of these spills involved non-petroleum-related chemicals. Traditional emergency responses or incident command structures (ICSs) that respond to chemical spills require coordinated efforts by predominantly government personnel from multiple disciplines, including disaster management, public health, and environmental protection. However, the requirements of emergency response teams for science support might not be met within the traditional ICS. We describe the US ICS as an example of emergency-response approaches to chemical spills and provide examples in which external scientific support from research personnel benefitted the ICS emergency response, focusing primarily on nonpetroleum chemical spills. We then propose immediate, near-term, and long-term activities to support the response to chemical spills, focusing on nonpetroleum chemical spills. Further, we call for science support for spill prevention and near-term spill-incident response and identify longer-term research needs. The development of a formal mechanism for external science support of ICS from governmental and nongovernmental scientists would benefit rapid responders, advance incident- and crisis-response science, and aid society in coping with and recovering from chemical spills.

Characterization of Disinfection By-Products from Chromatographically Isolated NOM through High-Resolution Mass Spectrometry.

As levels of natural organic matter (NOM) in surface water rise, the minimization of potentially harmful disinfection by-products (DBPs) becomes increasingly critical. Here, we introduce the advantage that chromatographic prefractionation brings to investigating compositional changes to NOM caused by chlorination. Fractionation reduces complexity, making it easier to observe changes and attribute them to specific components. Under the conditions tested (0.1-0.4 g of Cl to g of C without further additives), the differences between highly and less oxidized NOM were striking. Highly oxidized NOM formed more diverse Cl-containing DPB, had a higher propensity to react with multiple Cl, and tended to transform so drastically as to no longer be amenable to electrospray-ionization mass spectral detection. Less-oxidized material tended to incorporate one Cl and retain its humiclike composition. N-containing, lipidlike, and condensed aromatic structure (CAS)-like NOM were selectively enriched in mass spectra, suggesting that such components do not react as extensively with NaOCl as their counterparts. Carbohydrate-like NOM, conversely, was selectively removed from spectra by chlorination.

Residential tap water contamination following the Freedom Industries chemical spill: perceptions, water quality, and health impacts.

During January 2014, an industrial solvent contaminated West Virginia's Elk River and 15% of the state population's tap water. A rapid in-home survey and water testing was conducted 2 weeks following the spill to understand resident perceptions, tap water chemical levels, and premise plumbing flushing effectiveness. Water odors were detected in all 10 homes sampled before and after premise plumbing flushing. Survey and medical data indicated flushing caused adverse health impacts. Bench-scale experiments and physiochemical property predictions showed flushing promoted chemical volatilization, and contaminants did not appreciably sorb into cross-linked polyethylene (PEX) pipe. Flushing reduced tap water 4-methylcyclohexanemethanol (4-MCHM) concentrations within some but not all homes. 4-MCHM was detected at unflushed (<10 to 420 µg/L) and flushed plumbing systems (<10 to 96 µg/L) and sometimes concentrations differed among faucets within each home. All waters contained less 4-MCHM than the 1000 µg/L Centers for Disease Control drinking water limit, but one home exceeded the 120 µg/L drinking water limit established by independent toxicologists. Nearly all households refused to resume water use activities after flushing because of water safety concerns. Science based flushing protocols should be developed to expedite recovery, minimize health impacts, and reduce concentrations in homes when future events occur.

The cleaning method selected for new PEX pipe installation can affect short-term drinking water quality.

The influence of four different cleaning methods used for newly installed polyethylene (PEX) pipes on chemical and odor quality was determined. Bench-scale testing of two PEX (type b) pipe brands showed that the California Plumbing Code PEX installation method does not maximize total organic carbon (TOC) removal. TOC concentration and threshold odor number values significantly varied between two pipe brands. Different cleaning methods impacted carbon release, odor, as well the level of drinking water odorant ethyl tert-butyl ether. Both pipes caused odor values up to eight times greater than the US federal drinking water odor limit. Unique to this project was that organic chemicals released by PEX pipe were affected by pipe brand, fill/empty cycle frequency, and the pipe cleaning method selected by the installer.

Stormwater chemical contamination caused by cured-in-place pipe (CIPP) infrastructure rehabilitation activities.

Cured-in-place pipe (CIPP) is becoming a popular U.S. stormwater culvert rehabilitation method. Several State transportation agencies have reported that CIPP activities can release styrene into stormwater, but no other contaminants have been monitored. CIPP's stormwater contamination potential and that of its condensate waste was characterized. Condensate completely dissolved Daphnia magna within 24 h. Condensate pH was 6.2 and its chemical oxygen demand (COD) level was 36,000 ppm. D. magna mortality (100%) occurred in 48 h, even when condensate was diluted by a factor of 10,000 and styrene was present at a magnitude less than its LC50. Condensate and stormwater contained numerous carcinogenic solvents used in resin synthesis, endocrine disrupting contaminants such as plasticizers, and initiator degradation products. For 35 days, COD levels at the culvert outlets and downstream ranged from 100 to 375 ppm and styrene was 0.01 to 7.4 ppm. Although contaminant levels generally reduced with time, styrene levels were greatest 50 ft downstream, not at the culvert outlet. Cured CIPP extraction tests confirmed that numerous contaminants other than styrene were released into the environment and their persistence and toxicity should be investigated. More effective contaminant containment and cleaner installation processes must be developed to protect the environment.

Measurement Methods to Evaluate Engineered Nanomaterial Release from Food Contact Materials.

This article is one of a series of 4 that report on a task of the NanoRelease Food Additive project of the Intl. Life Science Inst. Center for Risk Science Innovation and Application to identify, evaluate, and develop methods that are needed to confidently detect, characterize, and quantify intentionally produced engineered nanomaterials (ENMs) released from food along the alimentary tract. This particular article focuses on the problem of detecting ENMs that become released into food indirectly from food contact materials. In this review, an in-depth analysis of the release literature is presented and relevant release mechanisms are discussed. The literature review includes discussion of articles related to the release phenomenon in general, as experimental methods to detect ENMs migrating from plastic materials into other (nonfood) complex matrices were determined to be relevant to the focus problem of food safety. From the survey of the literature, several "control points" were identified where characterization data on ENMs and materials may be most valuable. The article concludes with a summary of findings and a discussion of potential knowledge gaps and targets for method development in this area.

Four buildings and a flush: Lessons from degraded water quality and recommendations on building water management.

A reduction in building occupancy can lead to stagnant water in plumbing, and the potential consequences for water quality have gained increasing attention. To investigate this, a study was conducted during the COVID-19 pandemic, focusing on water quality in four institutional buildings. Two of these buildings were old (>58 years) and large (>19,000 m2), while the other two were new (>13 years) and small (<11,000 m2). The study revealed significant decreases in water usage in the small buildings, whereas usage remained unchanged in the large buildings. Initial analysis found that residual chlorine was rarely detectable in cold/drinking water samples. Furthermore, the pH, dissolved oxygen, total organic carbon, and total cell count levels in the first draw of cold water samples were similar across all buildings. However, the ranges of heavy metal concentrations in large buildings were greater than observed in small buildings. Copper (Cu), lead (Pb), and manganese (Mn) sporadically exceeded drinking water limits at cold water fixtures, with maximum concentrations of 2.7 mg Cu L-1, 45.4 µg Pb L-1, 1.9 mg Mn L-1. Flushing the plumbing for 5 min resulted in detectable residual at fixtures in three buildings, but even after 125 min of flushing in largest and oldest building, no residual chlorine was detected at the fixture closest to the building's point of entry. During the pandemic, the building owner conducted fixture flushing, where one to a few fixtures were operated per visit in buildings with hundreds of fixtures and multiple floors. However, further research is needed to understand the fundamental processes that control faucet water quality from the service line to the faucet. In the absence of this knowledge, building owners should create and use as-built drawings to develop flushing plans and conduct periodic water testing.

Diversity of organic components in airborne waste discharged from sewer pipe repairs.

Air-discharged waste from commonly used trenchless technologies of sewer pipe repairs is an emerging and poorly characterized source of urban pollution. This study reports on the molecular-level characterization of the atmospherically discharged aqueous-phase waste condensate samples collected at four field sites of the sewer pipe repairs. The molecular composition of organic species in these samples was investigated using reversed-phase liquid chromatography coupled with a photodiode array detector and a high-resolution mass spectrometer equipped with interchangeable atmospheric pressure photoionization and electrospray ionization sources. The waste condensate components comprise a complex mixture of organic species that can partition between gas-, aqueous-, and solid-phases when water evaporates from the air-discharged waste. Identified organic species have broad variability in molecular weight, molecular structures, and carbon oxidation state, which also varied between the waste samples. All condensates contained complex mixtures of oxidized organics, N- and S-containing organics, condensed aromatics, and their functionalized derivatives that are directly released to the atmospheric environment during installations. Furthermore, semi-volatile, low volatility, and extremely low volatility organic compounds comprise 75-85% of the total compounds identified in the waste condensates. Estimates of the component-specific viscosities suggest that upon evaporation of water waste material would form the semi-solid and solid phases. The low volatilities and high viscosities of chemical components in these waste condensates will contribute to the formation of atmospheric secondary organic aerosols and atmospheric solid nanoplastic particles. Lastly, selected components expected in the condensates were quantified and found to be present at high concentrations (1-20 mg L-1) that may exceed regulatory limits.

Regulatory Significance of Plastic Manufacturing Air Pollution Discharged into Terrestrial Environments and Real-Time Sensing Challenges.

Cured-in-place-pipe (CIPP) is an onsite plastic manufacturing technology used in the U.S. and has not been evaluated for regulatory compliance with federal air pollution laws. The practice involves the discharge of manufacturing waste into the environment. The study goal was to estimate the magnitude of volatile organic compounds (VOCs) discharged into the atmosphere for styrene and nonstyrene composite manufacture and examine low-cost air monitoring sensor reliability. Time-resolved emission analysis revealed that VOC emission was not only isolated to the thermal curing period but also occurred before and after curing. In addition to the styrene monomer, other gas-phase hazardous air pollutants regulated under the Clean Air Act were also emitted. Based on typical CIPP installations, 0.9 to 16.6 U.S. tons of emitted VOCs were estimated for styrene CIPPs, and 0.09 to 1.6 U.S. tons of emitted VOCs were estimated for nonstyrene CIPPs. Because the number and size of CIPPs manufactured in a single community can vary, the total air pollution burden will significantly differ across communities. Low-cost VOC sensors commonly utilized near CIPP manufacturing activities did not accurately quantify styrene and should not be relied upon for that purpose. Up to several thousand-fold detection differences were observed. Regulatory evaluation of CIPP air pollution and PID sensor reliability assessments are recommended.

Pulmonary and neurological health effects associated with exposure to representative composite manufacturing emissions and corresponding alterations in circulating metabolite profiles.

Cured-in-place pipe (CIPP) technology is increasingly being utilized to repair aging and damaged pipes, however, there are concerns associated with the public health hazards of emissions. CIPP installation involves the manufacture of a new plastic composite pipe at the worksite and includes multiple variable components including resin material, curing methods, and operational conditions. We hypothesize styrene-based composite manufacturing emissions (CMEs) will induce greater pulmonary inflammatory responses and oxidative stress, as well as neurological toxicity compared with nonstyrene CMEs. Further, these CME-toxicological responses will be sex- and time-dependent. To test the hypothesis, representative CMEs were generated using a laboratory curing chamber and characterized using thermal desorption-gas chromatography-mass spectrometry and photoionization detector. Styrene was released during staying, isothermal curing, and cooling phases of the process and peaked during the cooling phase. Male and female C57BL6/J mice were utilized to examine alterations in pulmonary responses and neurotoxicity 1 day and 7 days following exposure to air (controls), nonstyrene-CMEs, or styrene-CMEs. Serum styrene metabolites were increased in mice exposed to styrene-CMEs. Metabolic and lipid profiling revealed alterations related to CIPP emissions that were resin-, time-, and sex-dependent. Exposure to styrene-CMEs resulted in an influx of lymphocytes in both sexes. Expression of inflammatory and oxidative stress markers, including Tnfα, Vcam1, Ccl2, Cxcl2, Il6, Cxcl1, Tgfß1, Tgmt2, and Hmox1, displayed alterations following exposure to emissions. These changes in pulmonary and neurological markers of toxicity were dependent on resin type, sex, and time. Overall, this study demonstrates resin-specific differences in representative CMEs and alterations in toxicity endpoints, which can potentially inform safer utilization of composite manufacturing processes.

Chemical characterization of microplastic particles formed in airborne waste discharged from sewer pipe repairs.

Microplastic particles are of increasing environmental concern due to the widespread uncontrolled degradation of various commercial products made of plastic and their associated waste disposal. Recently, common technology used to repair sewer pipes was reported as one of the emission sources of airborne microplastics in urban areas. This research presents results of the multi-modal comprehensive chemical characterization of the microplastic particles related to waste discharged in the pipe repair process and compares particle composition with the components of uncured resin and cured plastic composite used in the process. Analysis of these materials employs complementary use of surface-enhanced Raman spectroscopy, scanning transmission X-ray spectro-microscopy, single particle mass spectrometry, and direct analysis in real-time high-resolution mass spectrometry. It is shown that the composition of the relatively large (100 µm) microplastic particles resembles components of plastic material used in the process. In contrast, the composition of the smaller (micrometer and sub-micrometer) particles is significantly different, suggesting their formation from unintended polymerization of water-soluble components occurring in drying droplets of the air-discharged waste. In addition, resin material type influences the composition of released microplastic particles. Results are further discussed to guide the detection and advanced characterization of airborne microplastics in future field and laboratory studies pertaining to sewer pipe repair technology.

School and childcare center drinking water: Copper chemistry, health effects, occurrence, and remediation.

The study goal was to better understand the risks of elevated copper levels at US schools and childcare centers. Copper health effects, chemistry, occurrence, and remediation actions were reviewed. Of the more than 98,000 schools and 500,000 childcare centers, only 0.2% had copper water testing data in the federal Safe Drinking Water Information System database. Of the facilities designated public water systems, about 13% had reported an exceedance. Schools that were not designated a public water system (PWS) also had exceedances. Few studies document levels in schools and childcare centers. Widely different sampling and remedial actions were reported. Flushing contaminated water was the most evaluated remedial action but was unreliable because copper quickly rebounded when flushing stopped. Building water treatment systems have been used, but some were not capable of making the water safe. The health risk was difficult to determine due to the limited occurrence data and lack of best management practice studies. A national drinking water testing campaign and field studies are recommended.

Prevalence of opportunistic pathogens in a school building plumbing during periods of low water use and a transition to normal use.

The spread of opportunistic pathogens via building water supply and plumbing is of public health concern. This study was conducted to better understand microbial water quality changes in a LEED-certified school building during low water use (Summer) and normal water use (Autumn). The copper plumbed building contained water saving devices, a hot water recirculation system, and received chloraminated drinking water from a public water system. Three separate sampling events were conducted during the summer break inside the building and another three sampling events were conducted after the school returned to session. Using quantitative PCR, Legionella spp. were detected in all water samples, followed by Mycobacterium spp. (99%). Mycobacterium avium (75%) and Acanthamoeba spp. (17.5%) throughout the building water system. Legionella pneumophila and Naegleria fowleri were not detected in any of the samples. The mean concentrations of Legionella spp., Mycobacterium spp., Mycobacterium avium, and Acanthamoeba spp. detected in water samples were 3.9, 5.7, 4.7, and 2.8 log10 gene copies per 100 ml, respectively. There was a statistically significantly difference in the mean concentrations of Legionella spp., Mycobacterium spp. and M. avium gene markers in water samples between school breaks and when school was in session. Cultivable Legionella were also detected in water samples collected during periods of low water use. This study highlights the need for routine proactive water quality testing in school buildings to determine the extent of drinking water quality problems associated with plumbing and direct action to remediate microbial colonization.