Estimating arsenic biotransfer factors from feed to chicken: a viable approach to animal feed risk assessment.

Reliable biotransfer factor (BTF) data are critical for animal-feed studies in human risk assessment. A wide range of BTF values have been reported (0.0015-0.83 d/kg), expressed as the ratio of total arsenic (tAs) concentration (µg/kg) in chicken to daily intake rate (µg/d) of tAs in feed (tAs/tAs). Data on inorganic As (iAs) for chicken meat and tAs concentrations for feed were obtained from our related study. Using the linear regression technique developed in this study, we estimated the BTF as 0.016 d/kg, as iAs/tAs (R2 > 0.7702) and 0.55 d/kg as tAs/tAs (R2 = 0.9743) for whole chicken meat. From a mass-balance perspective, we suggest that tAs be used as the denominator for the BTF unit. To illustrate our feed-risk assessment method, we analyzed commercial feeds for tAs concentration (n = 79). Consumption data for the general population (n = 2479) were obtained from a Taiwanese total diet study. Bivariate Monte Carlo simulations (n = 10,000) showed that the 95th percentile (P95) of estimated daily intake (EDI) was 0.002 µg/kg body weight (bw)/d as iAs (< the benchmark dose lower limit of 3.0 µg/kg bw/d). Our results thus show that the commercial chicken feeds assessed in this study are of low health concern for the general Taiwanese population. We discuss the factors that may have affected the assessment, such as the type of animals investigated, type of feeds, feed tested, type of chemical species used for BTF estimation and statistical approach.

Establishment of optimal QuEChERS conditions of various food matrices for rapid measurement of heterocyclic amines in various foods.

The optimal conditions for QuEChERS (quick, easy, cheap, effective, rugged and safe) with superior performance were established to rapidly extract 21 heterocyclic amines (HAs) from 9 categories of food matrices including meat and poultry, eggs, soy beans and products, composite foods, fish and seafood, grains, beer, dairy foods, and coffee. The QuEChERS conditions and the developed ultra-high performance liquid chromatography-tandem mass spectrometry analysis conditions were then applied to the determination of HAs in popular food products sold in the Taiwan market. The conditions comply with the food chemical analysis specifications of Taiwan Food and Drug Administration. Coffee products and braised products that require a longer cooking time contained relatively high content of HAs (mainly Harman and Norharman), and their consumption is relatively high resulting in relatively high intake of HAs from these products. The dietary intake of HAs in plant-based protein food products should also be of concern.

Establishment of an appropriate method for determining multiple heterocyclic amines in soy products processed with various methods.

A method using UPLC-MS/MS and a core-shell C18 column was developed to simultaneously determine 21 heterocyclic amines (HAs) in 15 min. Appropriate QuEChERS conditions were also established to conveniently extract HAs from soy products cooked with various methods. These conditions presented good analytical performance; limit of detection, limit of quantification, recovery (%), repeatability (coefficient of variation (CV) %) and intermediate precision (CV%) were 0.008 âˆ¼ 0.150 ng/g, 0.025 âˆ¼ 0.500 ng/g, 62 âˆ¼ 91%, ≤ 28% and ≤ 23% for tofu sample, and 0.003 âˆ¼ 0.100 ng/g, 0.010 âˆ¼ 0.350 ng/g, 64 âˆ¼ 93%, ≤ 19% and ≤ 20% for soy milk sample, respectively. HAs contents in the samples increased with cooking temperature and time. The tofu samples cooked by frying had much higher HAs content than those cooked by boiling and roasting. Norharman and Harman mainly contributed HAs content in all samples. For the general population in Taiwan, the highest estimated level of HAs consumed from the samples is 373.67 ng/day.

Human health risk simulation and assessment of heavy metal contamination in a river affected by industrial activities.

The human health risks caused by heavy metal contamination (As, Cd, Cr, Cu, Hg, Pb, Ni, and Zn) in the surface water of the Houjing River, the most contaminated river in southern Taiwan, were assessed in this study. Firstly, heavy metal contamination was evaluated by the contamination factors (CF) and the metal indexes (MI). Secondly, the human health risks due to heavy metal contamination were simulated using the Adaptive Risk Assessments Modeling System (ARAMS) through three scenarios; fish ingestion, dermal water contact, and incidental water ingestion during swimming. The hazard quotient (HQ) and the hazard index (HI) were used to evaluate non-carcinogenic risks, while carcinogenic risks were estimated by the lifetime cancer incidence risk index (CR) and the cumulative cancer risk (CCR). The results showed that the synergistic contamination of heavy metals in the surface water was severe (MI = 12.4), with the highest contribution from Cu, Ni, and Pb. Copper had the highest non-carcinogenic risk at the "adverse effect" level, while Ni and Cr had the highest carcinogenic risk at an "unacceptable" level. In addition, the cumulative risks of fish ingestion (HIFI = 6.75 and CCRFI = 1.25E-03) were significantly higher than those of the swimming scenarios (HI(DC + WI) = 1.94E-03 and CCR(DC + WI) = 9.32E-08). The results from this study will be beneficial for immediate and future contamination control measures and human health management plans for this study area. This study has also demonstrated the effectiveness of using ARAMS in human health risk assessment.

Evaluation of optimal QuEChERS conditions of various food matrices for rapid determination of EU priority polycyclic aromatic hydrocarbons in various foods.

Optimal QuEChERS (quick, easy, cheap, effective, rugged and safe) conditions with good accuracy, repeatability and precision were established to rapidly extract the European Union (EU) priority polycyclic aromatic hydrocarbons (PAHs) from various food matrices (Category: Poultry and Meat, Fish and seafood, Grains, Soy beans and products, Root vegetables and Coffee). The QuEChERS conditions combined with the established high performance liquid chromatography-fluorescence detection conditions were used to rapidly determine the PAHs in 19 popular cooked foods in Taiwan and their corresponding original materials. These conditions also meet the EU and Taiwan Food and Drug Administration specifications. Charcoal grilled, gas stove grilled and smoked foods had higher PAHs contents, while fried and electric oven-baked/baked foods had lower PAHs contents. In addition to the effects of cooking methods, the contamination of original materials by PAHs in the environment should also have an important impact on the contents of PAHs in these cooked foods.

Dietary exposure assessment of methylmercury and polyunsaturated fatty acids in saltwater fish and processed foods among Taiwanese women of child-bearing age and children: A novel core food-matching approach.

Saltwater fish is rich in health-promoting polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Excessive fish intake may also cause health hazards due to methylmercury (MeHg). A novel dose estimation method was proposed in this study to improve the quality of food matching by considering the usage ratio of cooking and processing methods in sampling design. In total, 39 table-ready samples were specified according to 2-3 common cooking methods, and MeHg and total mercury (THg) were analyzed. The results showed that mercury was detected in 20 samples (LOD = 0.01 µg/g). High MeHg samples included fried-Spanish mackerel (1.23 µg/g), non-cooked shredded swordfish (0.325 µg/g), pan-fried Spanish mackerel (0.248 µg/g), and non-cooked shredded salmon (0.208 µg/g). Consumption data (n = 166,911) were obtained from 24-h recalls in the 2005-2008 Nutrition and Health Surveys in Taiwan (NAHSIT). The average whole-group estimated daily intake (EDI_WG) was 0.018 (7.9% tolerable daily intake, TDI) for women of child-bearing age and 0.031 µg/day per kg body weight (13.6% TDI) for children. However, 95th percentile values (P95) of 90.4% TDI and 185% TDI were estimated for the two consumer-only populations, which have raised public health concerns. The ratio of % TDI to % daily reference intake (% DRI) was used as a risk-benefit (R/B) indicator. The top 4 R/B foods were: tuna sashimi (0.089 and 0.14), non-cooked shredded swordfish (0.033 and 0.052), fried-Spanish mackerel (0.027 and 0.043) and deep-fried fish balls (0.022 and 0.035) in the two perspective populations.

Comparison and establishment of appropriate methods to determine EU priority PAHs in charcoal-grilled chicken drumsticks with different treatments and their dietary risk assessments.

Three major polycyclic aromatic hydrocarbons (PAHs) analytical methods, gas chromatography-mass spectrometer (GC-MS), high performance liquid chromatography-photodiode-array detector (HPLC-PDA) and HPLC-fluorescence detector (FLD) were compared to analyze the European Union (EU) priority PAHs. In addition to the highest sensitivity, HPLC-FLD could be developed to rapidly determine the PAHs. A QuEChERS method was also established to rapidly extract the PAHs from chicken drumsticks. The method detection limits (0.004-0.25 ng/g), method quantification limits (0.01-0.75 ng/g), recoveries (67-114%), and coefficients of variations for intra- (1-15%) and inter- (1-21%) assays for the determination of the PAHs were in compliance with the EU and Taiwan Food and Drug Administration (TFDA) requirements. The PAHs contents in charcoal-grilled chicken drumsticks (without skin, with skin, and skin removal after processing) at different processing times were also determined by the developed methods. Although the risk assessment results for all samples showed a low level of concern, the presence of skin and long-term grilling had a greater impact on PAHs levels and dietary risks. Therefore, excessive processing should be avoided, and the skin of chicken drumsticks should be removed before and after charcoal-grilling to reduce the risk of PAHs intake.

Analyzing transient respirometric data by analytical algorithm for Monod kinetic parameters.

This study aims to develop an analytical algorithm with oxygen update (Ou) data obtained from transient respirometric measurement. Based on Monod kinetics, this study formulates a novel two-phase analytical model for an oxygen uptake rate plot (OUR vs. Ou) obtained by respirometric techniques. The first phase is a hyperbolic equation relating to exogenous and endogenous respiration, while the second phase is a linear equation for endogenous respiration only. An algorithm was therefore developed to analyze four Monod parameters by locating the best phase-separating point at which the absolute average relative error (ARE) of OUR is minimized. An analysis using test data on acetate verified that the algorithm is capable of transient kinetic parameter estimation with an ARE below 5-10%. A sensitivity analysis on domestic wastewater coupled with a Monte Carlo simulation concluded that the kinetic test must be conducted at a relatively high initial substrate level (So/Xo ≧ 1 and So/Ks ≧ 10) for reliable parameter estimation. Moreover, it is crucial to conduct the kinetic test with sufficient and acclimated seed culture for the degradation of substrate. The results of this study can be used to develop an automatic transient kinetic analyzer with modern programmable respirometers.

Environmental monitoring and benchmarking of VCM airborne emissions for a major PVC plant in Taiwan with 15 PVC plants in the USA.

Vinyl chloride monomer (VCM) is classified as group 1 carcinogenic to humans by the International Agency for Research for Cancer (IARC). In 2012, USEPA promulgated a new VCM emission standard as part of National Emission Standards for Hazardous Air Pollutants (NESHAP) for polyvinyl chloride (PVC) and copolymer plants. The standard was set by benchmarking of peer plants with maximum achievable control technology (MACT). This study performs an emission assessment of a world-class PVC plant in Taiwan according to the MACT analysis. The emission data obtained were then benchmarked with baseline emission estimates of 15 PVC plants in the USA. Results of this study show seven types of VCM emissions: stripped resin of suspension/dispersion, wastewater, process vent, heat-exchange system, storage tank, equipment leaks, and other sources (gasholder). All the emission factors are complied with their MACT emission limitations (MEL) and ranked either #1 or #2 among the 15 plants. They are also summed and benchmarked against the production capacity of each plant, showing a negative power function with a fair correlation (R2 = 0.73). Among seven types of emissions, stripped resin contributes the highest (51.7%) by average emission factor of the 15 plants plus this study plant.

Core food model of the Taiwan food supply for total diet study.

Following the core food (CF) models of the USA and France reported in the 2000s, this study presents the first oriental CF model, for total diet studies in Taiwan. First, we combined the four latest national dietary recall surveys from 2005 to 2012, data sets from the Nutrition and Health Survey in Taiwan (NAHSIT) covering all ages (1 to 65+ years old). In total, 3,098 NAHSIT food codes from 349,497 records of responses from 7,580 individuals were aggregated within a three-tiered scheme into 237 CFs in 54 subcategories and 16 categories. As with Western foods, Taiwanese foods were mainly aggregated by food type and major ingredient, processing method, cooking method or serving habit. In addition, we propose several categories typical to Taiwanese foods: (1) processed foods (e.g. rice paste, rice noodle, bean curd); (2) mixed foods (e.g. tomato fried with egg, Guangdong porridge) and stuffed staple foods (e.g. rice cake, zongzi); (3) Chinese Dim Sum (e.g. dumpling, salted bun); and (4) animal offal (e.g. pig liver, chicken kidney) and by-products (e.g. chicken head, pig foot). Systematic nomenclature and coding methods are also proposed. A computerised web model was developed using a graphical user interface (GUI) for automatic CF aggregation and inquiry of various consumption estimates according to the residing area, age group, and gender of consumers. Point estimates of weighted means were calculated for consumption rates (CR) based on the whole group (WG) or consumers only (CO). The CR and body weight (BW) of each individual were matched to calculate mean intake per unit body weight (g/kg bw/day). A general sample design procedure with the CF model is suggested for a total diet study (TDS) on target hazards. Strategies are also discussed for improving the quality of food matching in sample designs.

Environmental health risks perception, attitude, and avoidance behaviour toward municipal solid waste incinerator.

This study aims to assess the relationship between risk perception, attitude, and avoidance among residents toward an urban incinerator in Taichung, Taiwan. A cross-sectional study was conducted and three schools were enrolled. The case group was composed of 514 residents who live near an incinerator. The control group was composed of 264 people nearly the same age and who have lived in that area basically the same period of time. All participants were interviewed using a structured questionnaire. Results of this study showed that there was no significant difference between the exposure group and the control group in risk perception and attitude regarding the incinerator. However, the exposure group showed a significantly higher desire to move within one year or move sometime in the future than the control group. Therefore, these people should encourage the Environmental Protection Administration (EPA) to do everything it can to make sure that the incinerator operates safely.

Sampling design by the core-food approach for the Taiwan total diet study on veterinary drugs.

The core-food (CF) approach, first adopted in the United States in the 1980s, has been widely used by many countries to assess the exposure to dietary hazards at a population level. However, the reliability of exposure estimates (C × CR) depends critically on sampling methods designed for the detected chemical concentrations (C) of each CF to match with the corresponding consumption rate (CR) estimated from the surveyed intake data. In order to reduce the uncertainty of food matching, this study presents a sampling design scheme, namely the subsample method, for the 2016 Taiwan total diet study (TDS) on veterinary drugs. We first combined the four sets of national dietary recall data that covered the entire age strata (1-65+ years), and aggregated them into 307 CFs by their similarity in nutritional values, manufacturing and cooking methods. The 40 CFs pertinent to veterinary drug residues were selected for this study, and 16 subsamples for each CF were designed by weighing their quantities in CR, product brands, manufacturing, processing and cooking methods. The calculated food matching rates of each CF from this study were 84.3-97.3%, which were higher than those obtained from many previous studies using the representative food (RF) method (53.1-57.8%). The subsample method not only considers the variety of food processing and cooking methods, but also it provides better food matching and reduces the uncertainty of exposure assessment.

Screening procedure for airborne pollutants emitted from a high-tech industrial complex in Taiwan.

Despite the modernization of computational techniques, atmospheric dispersion modeling remains a complicated task as it involves the use of large amounts of interrelated data with wide variability. The continuously growing list of regulated air pollutants also increases the difficulty of this task. To address these challenges, this study aimed to develop a screening procedure for a long-term exposure scenario by generating a site-specific lookup table of hourly averaged dispersion factors (χ/Q), which could be evaluated by downwind distance, direction, and effective plume height only. To allow for such simplification, the average plume rise was weighted with the frequency distribution of meteorological data so that the prediction of χ/Q could be decoupled from the meteorological data. To illustrate this procedure, 20 receptors around a high-tech complex in Taiwan were selected. Five consecutive years of hourly meteorological data were acquired to generate a lookup table of χ/Q, as well as two regression formulas of plume rise as functions of downwind distance, buoyancy flux, and stack height. To calculate the concentrations for the selected receptors, a six-step Excel algorithm was programmed with four years of emission records and 10 most critical toxics were screened out. A validation check using Industrial Source Complex (ISC3) model with the same meteorological and emission data showed an acceptable overestimate of 6.7% in the average concentration of 10 nearby receptors. The procedure proposed in this study allows practical and focused emission management for a large industrial complex and can therefore be integrated into an air quality decision-making system.

Background levels of persistent organic pollutants in humans from Taiwan: perfluorooctane sulfonate and perfluorooctanoic acid.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have recently received attention due to their widespread contamination of the environment. PFOS and PFOA are stable in the environment and resistant to metabolism, hydrolysis, photolysis and biodegradation. PFOS and PFOA have been found in human blood and tissue samples from both occupationally exposed workers and the general worldwide population. This study aimed to determine the background levels of PFOS and PFOA in the Taiwanese population, investigate related factors, and compare exposure in Taiwan to that in other countries. The concentration of PFOS in the 59 serum samples collected from the general population in Taiwan ranged from 3.45 to 25.65ngmL(-1) (median: 8.52), and the concentration of PFOA ranged from 1.55 to 7.69ngmL(-1) (median: 3.22). There was a significant positive correlation (r=0.51; p<0.0001) between PFOS and PFOA concentrations. Males had higher concentrations of PFOA and PFOS than females. PFOS levels in serum increased with age. This study is the first investigation to reveal the PFOS and PFOA levels of serum samples in the general population of Taiwan. The levels of PFOS and PFOA in Taiwanese serum samples were comparable with those from other countries (PFOS: 5.0-35ngmL(-1), PFOA: 1.5-10ngmL(-1)).

Clinical characteristics and electrodiagnostic features in patients with carpal tunnel syndrome, double crush syndrome, and cervical radiculopathy.

Similar unilateral neck and upper limb symptoms are often due to various entrapment neuropathies; carpal tunnel syndrome (CTS) and cervical radiculopathy (CR) are common causes among them. Therefore, we investigated the clinical characteristics and electrodiagnostic features of patients with carpal tunnel syndrome, cervical radiculopathy, and both conditions, called double crush syndrome (DCS). The medical records and electrodiagnostic reports of 866 patients with suspected CTS and CR visited a tertiary-care hospital were retrospectively analyzed. After excluding 101 patients with confounding conditions, 151 (20%) patients were diagnosed to have sole cases of CTS; 362 (47%) patients were diagnosed to have sole cases of CR; 198 (26%) patients were diagnosed to have DCS, while 54 (7%) patients had mere symptoms. Sole cases of CR had the highest incidences of neck pain, upper back pain, wrist and hand weakness. Female patients had the highest incidences of all the diseases in their sixth decade. Male patients had comparably distinguished high occurrence of all the diseases in their fifth to sixth decades. Although comparison of nerve conduction studies between patients with mere symptoms and patients with sole cases of CTS or DCS showed statistical differences, comparison between the latter two revealed no difference. We found most patients referred for electrodiagnostic studies had cervical radiculopathy. High concomitant occurrence of CTS and CR suggests cautious evaluation of patients with upper limb symptoms is important, because the management of these conditions is quite different.

The effect of prenatal perfluorinated chemicals exposures on pediatric atopy.

BACKGROUND: The role of perfluorinated compounds (PFCs) in the immune system and allergic diseases is not well-known. This study examined the effects of pre-natal exposure to PFCs on immunoglobulin E (IgE) levels and atopic dermatitis (AD). METHODS: In Taiwan Birth Panel cohort study, newborns with cord blood and peri-natal factors (i.e. birth body weight, weeks of gestation, and type of delivery) gathered at birth were evaluated. At the age of 2 years, information on the development of AD, environmental exposures, and serum total IgE were collected. The AD and non-AD children were compared for the concentration of cord blood serum PFCs measured by Ultra-performance liquid chromatography/triple-quadrupole mass (UPLC-MS/MS). Correlations among cord blood IgE, serum total IgE at 2 years of age, and cord blood PFC levels were made. RESULTS: Of 244 children who completed the follow-up and specimen collections, 43 (17.6%) developed AD. Concentrations of cord blood serum perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonic acid (PFHxS) were median (range) 1.71 (0.75-17.40), 5.50 (0.11-48.36), 2.30 (0.38-63.87), and 0.035 (0.035-0.420)ng/mL, respectively. PFOA and PFOS levels positively correlated with cord blood IgE levels (per ln-unit: ß=0.134 KU/l, p=0.047 for PFOA; ß=0.161 KU/l, p=0.017 for PFOS). Analyses stratified by gender revealed that PFOA and PFOS levels positively correlated with cord blood IgE levels only in boys (per ln-unit: ß=0.206 KU/l, p=0.025 for PFOA; ß=0.175 KU/l, p=0.053 for PFOS). When dividing cord blood serum PFCs into quartiles in the fully adjusted models, AD had no significant association with PFOS. CONCLUSIONS: Pre-natal PFOA and PFOS exposures positively correlated with cord blood IgE levels.

Exploring the background features of acidic and basic air pollutants around an industrial complex using data mining approach.

Air pollution data around a monitored site are normally difficult to analyze due to highly inter-related meteorological and topographical factors on top of many complicated atmospheric chemical interactions occurred in local and regional wind fields. The challenge prompts this study to develop a comprehensive data-mining algorithm of cluster analysis followed by meteorological and interspecies correlations to mitigate the inherent data complexity and dissimilarity. This study investigated the background features of acidic and basic air pollutants around a high-tech industrial park in Taiwan. Monthly samplings were taken at 10 sites around the park in a year. The temporal distribution plots show a baseline with two characteristic groups of high and low peaks. Hierarchical cluster analysis confirms that high peaks were primarily associated with low speed south wind in summer for all the chemical species, except for F(-), Cl(-), NH(3) and HF. Crosschecking with the topographical map identifies several major external sources in south and southwest. Further meteorological correlation suggests that HCl is highly positively associated with humidity, while Cl(-) is highly negatively associated with temperature, both for most stations. Interestingly, HNO(3) is highly negatively associated with wind speed for most stations and the hotspot was found in summer and around the foothill of Da-Tu Mountain in the northwest, a stagnant pocket on the study site. However, F(-) is highly positively associated with wind speed at downwind stations to the prevailing north wind in winter, indicating an internal source from the north. The presence of NH(4)(+) stimulates the formation of NO(3)(-), SO(4)(-2) (R=0.7), and HNO(3), H(2)SO(4), NH(3) (R=0.3-0.4). As H(2)SO(4) could be elevated to a level as high as 40% of the regulated standard, species interactions may be a dominate mechanism responsible for the substantial increase in summer from external sources.

Characterization of volatile organic compounds in the vicinity of an optoelectronics industrial park in Taiwan.

This study aimed to determine the concentration of volatile organic compounds (VOCs) and investigate the impacts of traffic and industrial activities on the concentration of VOCs near the Central Taiwan Science Park (CTSP) in Taiwan during 2005. Twelve-hour canister sampling was performed at 10 sites near CTSP every season. Samples were analyzed by gas chromatography with a mass-selective detector. The traffic flow rate, industrial production rates, and meteorological information were also collected to assess their impacts on VOC concentrations using multiple linear regression models. The major components determined in the atmosphere were toluene (29.4-218.8 microg m(-3)), acetone (30-71.3 microg m(-3)), m/p-xylene (7.8-51.7 microg m(-3)), and ethanol (16.4-47.8 microg m(-3)); only ethanol revealed a pattern of increasing concentration from spring to winter. The log-transformed mean concentrations of toluene, acetone, and ethanol were significantly associated with the production rates of the optoelectronic companies after adjustment for traffic flow and meteorological factors (P < 0.05). There was no significant association between the total traffic flow rate and any log-transformed mean concentrations of VOCs. Each $1 million (U.S.) increase in optoelectronic sales was significantly associated with increasing mean concentrations of 1.29 +/- 1.08 microg m(-3) for toluene, 1.13 +/- 1.05 microg m(-3) for acetone, and 1.25 +/- 1.09 microg m(-3) for ethanol. The authors' findings suggest that optoelectronic industrial activities are still the predominant source for VOC emissions surrounding this industrial park.

Respirometric evaluation by graphical analysis for microbial systems.

Analysis of respirometric graphs for system diagnosis has recently drawn much attention due to the nature of the test being a fast method with reliable oxygen uptake (Ou) data. In this study, a new graphical analysis procedure is proposed, using the oxygen uptake rate (OUR) vs. Ou respirogram because of its distinct characteristics that provides easy visual inspection. The OUR plot is typically divided into two respiration phases, and each one of these phases can be simulated by a previously derived analytical equation. Based on the 2-phase model, five characteristic parameters (CPs) were derived for the OUR respirogram. Mathematically the 5 CPs can be related to the system parameters (SPs), including the four Monod kinetic parameters and two operating conditions (initial substrate and biomass concentration). Sensitivity analyses were then conducted to assess the 5 CPs for the level of effect caused by system parameters (SPs). This study also conducted respirometric tests under batch operation to evaluate the applicability of the graphical analysis method. Based on the 5 CPs estimated from the OUR respirogram of the tests, it can be concluded that respirometric tests normally experience the problems associated with initial lag, non-uniform seeding, and inadequate mixing.

Disinfection of hospital wastewater by continuous ozonization.

The disinfection of hospital wastewaters using the ozonization process was studied. The concentrations of ozone required to reach a sudden drop of coliform and Pseudomonas aeruginosa in the wastewater are 4.0-7.0 and 3.0-5.0 mg L(-1), respectively. For the hospital wastewater, the disinfection efficiencies were 0.518S(-1.1) for coliforms, 0.509S(-1.06) for Pseudomonas aeruginosa and 0.254S-(1.54) for total count, respectively. As to the effects of ozone input methods on the disinfection efficiency, the continuous ozonization process was ten times higher than the batch input process. The low COD removal rate was obtained at 25.0 mgL(-1) of ozone concentration for hospital wastewater. However, more biodegradable compounds resulted in the treated mixture.