Environmental Protection Agency Standards Research Articles

Assessing the feasibility of using a closed landfill for agricultural graze land.

Once landfills are closed and maintained according to the US Environmental Protection Agency's standards and regulations, they are potential sites for revitalization efforts, particularly via agricultural activities. This project was commissioned by the City of Tucson Environmental Services Department as part of an effort to explore ways to reuse one or more of the 16 landfills the department manages in the Tucson metropolitan area. The objective of this project was to assess the feasibility of using a closed landfill to support safe goat browsing. A site history and investigation was conducted at the Harrison Landfill in Tucson, Arizona, to characterize the soil quality and uptake of deleterious metals by the following plants observed at the landfill: Pennisetum ciliare (buffel grass), Baccharis sarothroides (desert broom), Salsola tragus L. (Russian thistle), Larrea tridentata (creosote), Tamarix ramosissima (salt cedar), and Atriplex canescens (fourwing saltbush). Site characterization data were combined with known goat browsing and plant consumption patterns to determine exposure risks. It was observed that soil concentrations of metals (Al, Ag, As, Be, Ba, Fe, Co, Cu, Cr, Cd, Fe, Mn, Ni, V, Se, Mo, Sn, Sb, Pb) did not exceed Arizona Department of Environmental Quality's soil remediation levels. Tamarix ramosissima, Baccharis salicifolia (willow baccharis), Pennisetum ciliare, Salsola tragus L., Baccharis sarothroides, Larrea tridentata, and Atriplex canescens contained metal concentrations that fell well within maximum tolerable levels. In general, this project determined that after soil and plant assessment, urban, arid landfills may be used effectively for economic development through agricultural grazing ventures.

Clinical Evaluation of a Chairside Amalgam Separator to Meet Environmental Protection Agency Dental Wastewater Regulatory Compliance.

The aim of this study was to evaluate the performance of a commercially available chairside amalgam separator (CAS) in a clinical setting in which a relatively high number of amalgam restorations are placed. Performance parameters investigated included service life, amalgam collected, mercury concentrations in effluent, and solids retention efficiency. CASs were tested per International Organization of Standardization (ISO) 11143:2008 prior to installation in a military dental treatment facility and after removal from service (n=4) in order to confirm compliance with the recently enacted United States Environmental Protection Agency (EPA) Effluent Limitations Guidelines and Standards for the Dental Category. During the units' time in service, biweekly effluent grab samples were collected from the high-volume evacuation system of each chair (n=6) and analyzed for total mercury concentration by inductively coupled plasma mass spectrometry (ICP-MS). The mean total accumulated solids at the end of service life (n=6) was determined for potential design optimization. The service life expectancy in a military dental treatment facility was determined in terms of calendar and workdays. Procedural data were collected to determine the daily mean number of amalgam surfaces placed during the service life of each chairside amalgam separator (n=9). The CAS evaluated met minimum EPA compliance requirements when used in a military dental treatment facility. The solids removal efficiency at the end of service life was 99.82% ± 0.14% (n=4). The mean service life (n=8) was 131.6 ± 45.1 calendar days (67.1±37.6 workdays). Effluent mercury concentrations ranged from 0.05 to 11.93 mg/L. Total solids accumulated in each CAS (n=6) at the end of service life was 195.4 ± 63.4 g. The mean number of amalgam surfaces placed per workday during the service life span of each CAS was 8.4 ± 1.4.

Removal of Nitrate and Ammonia from Wastewater

Ammonia and nitrate contamination of groundwater, surface water, and other water resources is considered a serious environmental and human health issue that causes several problems like algae bloom, fatal illnesses specially for the infant under 6 months. Electrochemical techniques for ammonia oxidation and nitrate reduction reactions are usually straightforward, energy-efficient, environmentally-friendly, and easy to control. Electrochemical techniques for separate removal of ammonia and nitrate has been extensively studied. However, in this work, we demonstrate a new process that addresses both water pollutants simultaneously in a single cell that leads to a considerable energy saving in the order of 90 % and 35-65 % less energy per grams of ammonia and nitrate removal, respectively. A new flow cell with novel electrode architectures is introduced to perform both ammonia/nitrate removal simultaneously. The concentration of nitrate and ammonia were measured according to the Environmental Protection Agency (EPA) standards which is a UV-vis spectrophotometric based technique, and ammonia Ion Selective Electrode (ISE-THERMO), respectively. Effect of electrode loading and other process variables on the ammonia and nitrate removal rates were evaluated. Findings of this work will be presented at the meeting.

Estimation of Radon gas concentration in soil and drinking water supply samples of Kirkuk governorate, Iraq

Radon gas is the second cause of lung cancer and it is found naturally in rocks, soil ground and surface water. In this study, Radon gas concentration measurements were performed in (39) drinking water and (29) soil samples for Kirkuk City. It is found that the value of Radon (Rn) concentration in drinking water ranged from ( 0.07 -5.01 ) Bq /L with an average of ( 0.97 ) Bq/L. These results showed that Radon concentration in Kirkuk City drinking water are within the United State Environmental Protection Agency(EPA) and World Health Organization(WHO) standards maximum contaminated level (MCL) of 11 Bq /L. The finding:- of this study refer that no risk from exposure to Radon gas in Kirkuk drinking water supply.From other hand, Radon in soil results showed that mean values was( 381.65± 189) Bq/m3,with maximum and minimum value 883and 87 Bq/m3 respectively. This results lied within the allowable standards adopted by International Commissions of Radon Protection(ICRP) which is (200-800) Bq/m3 . By comparing the results of present study with other local studies in different sites all over Iraq, it can be noticed that the finding of this study were greater than most of other studies results. That difference can be explained due to geological structure diversity of different governorate in Iraq, as Radon gas generated from soil and correlate strongly to soil structure and rock types.

Spatial and temporal dynamics of dissolved nutrients and factors affecting water quality of Chilika lagoon

Water quality of Chilika lagoon was assessed for pre- and post-monsoon seasons. A marked spatial and temporal variability in the water quality was observed in this study. Principal component analysis (PCA) reveals the influence of salinity, anthropogenic factors, as well as vegetation on the water quality. The higher concentration of nitrate (NO3−) and phosphate (PO43−) in certain pockets of the lagoon water was due to the prevalence of agricultural, municipal, and domestic waste. A positive correlation between PO43− and DSi indicates their terrigenous input from freshwater influx. Cyclone Phailin had profound impact on several water quality parameters. pH, dissolved oxygen (DO), and dissolved inorganic carbon (DIC) are governed largely by the presence of macrophytes. The impact of severe cyclone Phailin can be assessed from the very low salinity values persisting in the lagoon even 2.5 months after the cyclone hit Odisha coast. Some toxic heavy metals like Copper (Cu), Lead (Pb), Nickel (Ni), Cobalt (Co), Manganese (Mn), and Iron (Fe) exceeded the Environmental Protection Agency (EPA) standards at many locations in both the seasons. Non-conservative behavior of nutrients indicates well mixed nature of lagoon which is also indicative of good primary productivity. Northern sector (NS) of the lagoon is susceptible to eutrophication being riverine influenced region. Southern sector has more stable ion chemistry as a result of least freshwater discharge, constant supply of saline water, and lesser water renewal.

Impact of NOx Emissions Released from a Gas Turbine-Based Power Plant on the Ambient Air Quality

The number of gas turbine- (GT-) based power plants is rapidly increasing to meet the world’s power demands. Until a few years ago, fossil fuel, and specifically fuel oil, was considered the major energy source for gas turbine operation. Due to the high amount of pollution that fuel oil generates, natural gas has become a popular source of energy due to its lower emissions compared to fuel oil. As a result, many GTs have switched to natural gas as an alternative to fuel oil. However, pollutants expelled from GT-based power plants operating on natural gas impact surrounding air quality. The objective of this study was to examine the dispersion of nitrogen oxides (NOx) emitted from a GT-based power plant located in the Sultanate of Oman. Supported by CALPUFF dispersion modeling software, six scenarios were investigated in this study. The first four scenarios considered a case where the GT-based power plant was operating on natural gas during winter and summer and for open and combined cycle modes. The remaining two scenarios considered, for both open and combined cycle modes, the case where the GT-based power plant was operating on fuel oil. Whether run by natural gas or fuel oil, CALPUFF simulation results for both seasons showed that NOx concentrations were higher when GTs were used in the combined cycle mode. The concentrations were still lower than the allowable concentrations set by the United States Environmental Protection Agency (U.S. EPA) standards. In contrast, for the case where the power plant operated on fuel oil, the NOx one-hour average simulated results exceeded the allowable limits only when the combined cycle mode was activated.

Degradation of cyanide from gold processing effluent by H2O2, NaClO and Ca(ClO)2 combined with sequential catalytic process

This work investigates the removal of cyanide as a noxious pollutant in the gold processing effluent (Aq-Dara mine, Takab, Iran) using H2O2, H2O2+Fe(II) (Fenton), H2O2+Cu(II), NaClO and Ca(ClO)2 oxidants. Implementation of purification operation was carried out by varying the parameters including pH, oxidant dosage, temperature and time of the reaction. The results show that the oxidants have the highest efficacy at pH 10-12, while the Fenton process has the highest efficiency at pH 8. The results confirm that Ca(ClO)2 is the best oxidant due to the shorter time, low reaction rate, high degradation of cyanide and low cost. The obtained results of response surface methodology optimization show that cyanide degradation has a direct relation to temperature, amount of oxidant, time and catalyst dosage parameters and has an inverse relation to pH. Also, the cyanide elimination efficiency is more than 99.5% and residual cyanide less than Environmental Protection Agency standards and 40% of the consumed water can be compensated by the effluent treatment and its return to the factory's processing circuit. Keywords: Oxidation Process; Gold Processing Effluents Treatment; Cyanide Degradation; Non-linear Kinetic Modeling, Response Surface Method.

Inorganic Pollutants in the Water of Midland and Odessa, Permian Basin, West Texas

The objective of this study is to evaluate the public water contamination in the cities of Midland and Odessa, West Texas. Even though both cities are geographically close, their sources of water for public use are different. For this study, the copper-, lead-, arsenic-, nitrate-, and chromium-level reports in drinking water, provided by the cities from 2008 to 2017, were organized and analyzed using Cubic Hermite Interpolation. The results for each contamination per city were compared and contrasted with the Environmental Protection Agency (EPA) standards. Also, this study proposed possible risks to human health, as well as potential origins of the pollutants. Finally, conclusions about the quality of water for human consumption and possible reasons behind the difference of results between the 2 cities were made.

Trace metal concentrations in surface water and pore water sediment of coastal aquaculture ponds, Bangladesh

This study investigates contamination of surface water and pore water sediment by trace metals at the three coastal fish farms of Noakhali district in Bangladesh using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The World Health Organization (WHO) and United States Environmental Protection Agency (USEPA) standards were used as the baseline for the evaluation of surface water pollution and contamination of the sediments respectively. Cr and Cd concentrations in the surface water exceeded the reference limit, but there was no metal contamination of the pore water sediment. The average trace metals concentrations in both surface water and pore water sediment respectively showed similar trends Cr> Pb > Cu> Zn > Cd. All the metals studied exhibit negative Igeo values and CF<1 indicating uncontaminated sediment quality. The results of this study indicate that surface water of aquaculture ponds may be a possible source of trace metals which could be of health concern.

Lead Environmental Pollution and Childhood Lead Poisoning at Ban Thi Commune, Bac Kan Province, Vietnam.

Lead poisoning is a public health problem in many areas of the world. Children are at particularly high risk for adverse effects of lead exposure; even at low concentrations, lead can affect physical, mental, and behavioral development. Children living near lead-zinc mines are at high risk for environmental lead poisoning, especially the contaminated soil. We conducted a cross-sectional descriptive study in Ban Thi Commune, northern Vietnam. 195 children (92,9% participation) aged 3-14 years old (average: 7.69 ± 2.90) were randomly selected from a list of all children prepared by the village health collaborators. 109 (55.90%) were boys and 86 (44.10%) were girls. The research measures were the lead concentration in native soil and the children's total blood lead concentration determined by the inductively coupled plasma-mass spectrometry (ICP-MS) method. The results showed that lead content in soil was many times higher than American Environmental Protection Agency and Vietnam standards (average 2980.23 ± 6092.84 mg/kg dry weight of soil (range 80.05 – 33820.62)). Average blood lead levels for children were 15.42 ± 6.45 μg/dL (95% CI: 14.50 -16.33 μg/dL). The percentage of children with lead levels >10 μg/dL (value considered to be lead poisoning for children according to the Ministry of Health of Vietnam) was 79.49% of the total number of children. None of the children in this study had blood lead level (BLL) that required chelation treatment according to Vietnam MOH guideline (BLL ≥45 μg/dL). There is weakly evidence that lead exposure relates to the physical development of children. Children with low lead concentrations (less than 10 μg/dL) had height and weight of 1.47-3.51 cm and 1.19-2.81 kg, greater than those with BLL >10 μg/dL (p>0.05).

Dispersion and deposition estimation of fugitive iron particles from an iron industry on nearby communities via AERMOD.

Emission of fugitive iron particles from anthropogenic sources can have significant effects on the human health and the environment. In this study, a regulatory air pollutant dispersion model (AERMOD) was implemented to predict the dispersion and deposition of fugitive iron particles towards a mid-sized residential area in Sultanate of Oman. The performance of the model was validated using air, soil, and dust fall samples. PM10 was found as the most abundant iron particles in the soil samples. The results showed that the maximum daily concentration level of fugitive iron particles simulated through AERMOD was 7.19μg/m3. Statistical analysis, including fractional bias (FB), normalized mean square error (NMSE), and predicted/observed ratio (Pred./Obs.), showed a reliable agreement in accuracy and precision between the datasets (for air samples FB = 0.024, NMSE = 0.001, Pred./Obs. = 0.976; for dust fall samples FB = -0.004, NMSE = 0.000, Pred./Obs. = 1.004). However, uncertainties and differences were from the external sources, such as other industries in the region. The results presented that the concentration levels were below the national and international guidelines proposed by the US Environmental Protection Agency (USEPA) and Omani Ambient Air Quality Standards (OAAQS). The methodology followed and the developed dispersion model can be generalized to other industries from which the dispersion of fugitive metal particles need to be evaluated as a potential route for human exposure. Graphical abstract ᅟ.

Today's Hearing Technologies: Definitions, Regulations, Overlaps

Today's Hearing Technologies: Definitions, Regulations, Overlaps

Reuse of materials from a Sustainable Drainage System device: Health, Safety and Environment assessment for an end-of-life Pervious Pavement Structure

Pervious pavement systems can have a life span of about 20years but, at end-of-life, it becomes necessary to evaluate the state of the infrastructure to determine whether they pose a health and safety risk to workers during dismantling, and also determine potential reuse of the waste material generated. In this paper, we report of an investigation conducted to evaluate whether Pervious pavement systems are hazardous to human health at end-of-life and also to assess the mobility of the stormwater pollutants trapped in the system as a measure of their potential release to receiving systems such as water-bodies and groundwater systems. After decommissioning, the pervious pavement structure was sampled for analysis including Gas Chromatography, inductively coupled plasma spectroscopy and, leachate analysis. Results show that carcinogenic risks were significantly below the regulatory limit of 1×10–6 while, the hazard quotients and cumulative hazard indices were also below regulatory value of 1, based on United States Environmental Protection Agency standards. Furthermore, mean concentrations of benzene, toluene, ethylbenzene and xylene were significantly less than the UK soil guideline values. The results of the leachate analysis show that the metals of concern, Pb, Zn, Cr, Ni, Cd and Cu were all below the threshold for reuse applications such as irrigation purposes as they were all below the regulatory limits such as Food and Agriculture Organization and, United States Environmental Protection Agency standards. Finally, the evaluation of potential reuse and recycling purposes indicate that wastes generated from the dismantling of the PPS are within limits for recycling as aggregates for other civil engineering projects as per European Union standards. This has potential to enhance UK's drive to achieve the target of 70% level of construction & demolition waste recovery for reuse and recycling by the year 2020 as per European Union Water Framework Directive.

Investigation of the Concentration of Air Pollutants in Ambient Air of Babol City

Background: The air quality and its impact on the environment, especially on human health, are considered as a significant issue of concern by major public and governmental organizations. Therefore, monitoring of air pollutants is necessary to design control plans. This study aimed to evaluate the criteria for pollutants in the ambient air of Babol city. Methods: This descriptive and cross-sectional study was conducted on 136 samples obtained from 17 sampling stations during 2013, and the samples were collected using the respective devices on the site. The data were analyzed by ANOVA using Excel and SPSS software. Then, the results were compared with the national environmental protection agency (EPA) standards. Results: Among the samples obtained from 8 sampling stations, the maximum mean concentration of particulate matter (PM) was 0.0285 ± 0.007 μg/m3 in Shohada square, and the minimum was 0.024 ± 0.009 μg/m3 at the station at Mohammad Hassan Khan bridge; these are lower than the standard values. Also, the amount of carbon monoxide, nitrogen dioxide, and sulfur dioxide in all stations was zero, so the air quality index (AQI) was less than 50 in all cases. Conclusions: The findings of this research show that the measured concentration of particles and other pollutants was less than the EPA and WHO standards; therefore, Babol has clean and healthy air.

Fuel consumption for various driving styles in conventional and hybrid electric vehicles: Integrating driving cycle predictions with fuel consumption optimization

ABSTRACTImproving fuel economy and lowering emissions are key societal goals. Standard driving cycles, pre-designed by the US Environmental Protection Agency (EPA), have long been used to estimate vehicle fuel economy in laboratory-controlled conditions. They have also been used to test and tune different energy management strategies for hybrid electric vehicles (HEVs). This paper aims to estimate fuel consumption for a conventional vehicle and a HEV using personalized driving cycles extracted from real-world data to study the effects of different driving styles and vehicle types on fuel consumption when compared to the estimates based on standard driving cycles. To do this, we extracted driving cycles for conventional vehicles and HEVs from a large-scale U.S. survey that contains real-world GPS-based driving records. Next, the driving cycles were assigned to one of three categories: volatile, normal, or calm. Then, the driving cycles were used along with a driver-vehicle simulation that captures driver decisions (vehicle speed during a trip), powertrain, and vehicle dynamics to estimate fuel consumption for conventional vehicles and HEVs with power-split powertrain. To further optimize fuel consumption for HEVs, the Equivalent Consumption Minimization Strategy (ECMS) is applied. The results show that depending on the driving style and the driving scenario, conventional vehicle fuel consumption can vary widely compared with standard EPA driving cycles. Specifically, conventional vehicle fuel consumption was 13% lower in calm urban driving, but almost 34% higher for volatile highway driving compared with standard EPA driving cycles. Interestingly, when a driving cycle is predicted based on the application of case-based reasoning and used to tune the power distribution in a hybrid electric vehicle, its fuel consumption can be reduced by up to 12% in urban driving. Implications and limitations of the findings are discussed.

Health risk assessment model for lead contaminated soil in Bagega Community, Nigeria

The study developed health risk assessment model for lead contaminated soil in Bagega community using United States Environmental Protection Agency (US EPA) and Canadian Standards Association (CAS) standard procedures. Questionnaires were used to investigate the background causes and exposure pathways of lead contaminated soil. Soil samples were collected at five different sites and cancer health risk values were estimated using equations proposed by US EPA. The results show that 84.0 % of the respondents agreed that the causes of lead poisoning in the study area were due to the activities of artisanal gold miners. The major exposure pathways to lead contaminated soil are ingestion, dermal contact and inhalation while the soil ingestion generates high cancer risk, dermal contact generates low cancer risk and that of inhalation was insignificant when compared with 1.00E-06 (mg/kg/day) WHO cancer risk standard. The mean cancer health risk value for combined exposure pathway is ranged from 1.49E-03 mg/kg/day to 5.99E-03 mg/kg/day. The study established that lead contaminated soil posed cancer health risk to the people of the study area.

Evaluation of hospital infectious waste management in Bandung region

Hospital infectious waste (HIW) has become an important issue as it possesses potential health risk and damage to the environment. HIW, if not handled in a proper way, could be a potential source of diseases such as HIV, hepatitis B&C, and other bacterial diseases that cause serious threat to human health. Therefore, an extra attention is needed for its safe and proper disposal. The sustainable management of infectious waste requires a holistic approach to monitor and evaluate the implementation of hospital infectious waste handling. Based upon sample assessment, a brief overview of current implementation of hospital infectious waste management (HIWM) in Bandung region is provided. The assessment included a 50-point check list referring to the standard Environmental Protection Agency (EPA) Guideline. The assessment of HIW management was conducted in seven hospitals. In general hospitals in Bandung region conform 57 from 100% assessment score. This is a proof that HIWM was still conducted improperly in Bandung region. Private hospitals provide better score (68%) compared to government-owned hospitals (41%) whereas accredited hospitals provide a higher score (61%) compared to hospitals with non-accreditation (22%). In addition, specific hospitals provide better compliance performance (74%) compared to general hospitals (50%). Hospitals with health worker status provided a better score (68%) than hospitals with non-outsourcing health worker status (30%). Kruskal-Wallis test showed that the value of Asymp.sig 0.000 < 0.05, significant differences were found for evaluation of HIWM between 7 hospitals. In Bandung region, the HIW management was still conducted improperly; this study provides baseline data for further research into risk assessment of HIW management.

Utilization of graphene oxide for improving the environmental compatibility of cement-based materials containing waste cathode-ray tube glass

Abstract Utilization and processing of waste cathode ray tube (CRT) glass causes serious environmental damage due to its presence of lead and huge growing volume. The use of waste CRT glass in cement-based materials is an effective recycling method, whereas the huge amount of waste CRT glass usually results in severe lead leaching and weakened interfacial bonding. This paper presents an effective method for improving the lead immobilization and microstructure of the interfacial transition zone between cement paste and waste CRT glass (30 and 60 wt% of fine aggregates) using graphene oxide (GO) (up to 0.10 wt%). In order to investigate the environmental compatibility of the GO-waste CRT cement mortars, the standard toxicity characteristic leaching procedure (TCLP) was performed for lead leaching evaluation, and their mechanical properties were examined. Moreover, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) observation with backscattered electron mode were conducted. The results of TCLP indicate that the degrees of lead leaching from the waste CRT cement-based materials with both fine (0.075–0.15 mm) and coarse (8–9.5 mm) size containing 0.1 wt% GO were significantly lower than the regulatory limit specified by the United States Environmental Protection Agency and Chinese standard. The data obtained via mechanical testing revealed that the presence of 60 wt% waste CRT reduced its 28-day compressive and flexural strengths only slightly, whereas 0.1 wt% GO addition significantly increased their values. By analyzing the thermogravimetric and microstructural results, it was found that the increased formation of portlandite (CH) and calcium-silicate-hydrate (C S H) caused by GO addition reduced the number of interconnected cracks and pores and improved the properties of the interface between waste CRT glass and cement paste. This obtained improvement in environmental compatibility of the waste CRT cement mortars not only examines the reduced lead pollution caused by GO addition, but also sustainably promotes the industrial utilization of toxic waste CRT glass.

Probabilistic assessment of the potential indoor air impacts of vent-free gas heating appliances in energy-efficient homes in the United States

ABSTRACTUse of vent-free gas heating appliances for supplemental heating in U.S. homes is increasing. However, there is currently a lack of information on the potential impact of these appliances on indoor air quality for homes constructed according to energy-efficient and green building standards. A probabilistic analysis was conducted to estimate the impact of vent-free gas heating appliances on indoor air concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), carbon dioxide (CO2), water vapor, and oxygen in “tight” energy-efficient homes in the United States. A total of 20,000 simulations were conducted for each Department of Energy (DOE) heating region to capture a wide range of home sizes, appliance features, and conditions, by varying a number of parameters, e.g., room volume, house volume, outdoor humidity, air exchange rates, appliance input rates (Btu/hr), and house heat loss factors. Predicted airborne levels of CO were below the U.S. Environmental Protection Agency (EPA) standard of 9 ppm for all modeled cases. The airborne concentrations of NO2 were below the U.S. Consumer Product Safety Commission (CPSC) guideline of 0.3 ppm and the Health Canada benchmark of 0.25 ppm in all cases and were below the World Health Organization (WHO) standard of 0.11 ppm in 99–100% of all cases. Predicted levels of CO2 were below the Health Canada standard of 3500 ppm for all simulated cases. Oxygen levels in the room of vent-free heating appliance use were not significantly reduced. The great majority of cases in all DOE regions were associated with relative humidity (RH) levels from all indoor water vapor sources that were less than the EPA-recommended 70% RH maximum to avoid active mold and mildew growth. The conclusion of this investigation is that when installed in accordance with the manufacturer’s instructions, vent-free gas heating appliances maintain acceptable indoor air quality in tight energy-efficient homes, as defined by the standards referenced in this report.Implications: Probabilistic modeling of indoor air concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), carbon dioxide (CO2), water vapor, and oxygen associated with use of vent-free gas heating appliances provides new data indicating that uses of these devices are consistent with acceptable indoor air quality in “tight” energy-efficient homes in the United States. This study will provide authoritative bodies such as the International Code Council with definitive information that will assist in the development of future versions of national building codes, and will provide evaluation of the performance of unvented gas heating products in energy conservation homes.

Variation of United States environmental regulations on pesticide soil standard values

To specify the maximum allowable pesticide concentration in soil, pesticide residential soil regulatory guidance values (RGVs) have been promulgated by U.S. state regulatory jurisdictions to protect human health. A total of 12,451 RGVs for 456 identified pesticides adopted by 46 states were analyzed to evaluate whether there is the agreement among pesticide standard values regulated by the U.S.-related jurisdictions. Among them 62 pesticides with at least 50 RGVs were defined as the commonly regulated pesticides, and seven pesticides with at least 100 RGVs were defined as the most commonly regulated pesticides. A total of 12 states have provided over 500 pesticide soil RGVs and Texas alone has provided at least 1140 RGVs. Results indicate that these pesticide soil RGVs promulgated by the U.S. state jurisdictions for an individual pesticide could vary in a wide range of over six (DDT), seven (alpha-HCH), or even nine (Dieldrin) orders of magnitude. On the other hand, all of the seven most commonly regulated pesticides have a large RGV data cluster in which the state jurisdiction RGVs shared the U.S. Environmental Protection Agency (U.S. EPA) standards. To examine whether those pesticide soil RGVs could protect human health, cancer and non-cancer risk uncertainty bounds were calculated for the seven most commonly regulated pesticides. Results show that for the most commonly regulated pesticides, a total of 265 (41.8% of the total) soil RGVs exceeded the cancer risk uncertainty upper bounds and 30 (4.5% of the total) soil RGVs are above the non-cancer risk uncertainty bounds, which indicates that those RGVs cannot protect human health when exposing to the pesticides from soil.