Effect of environmental factors on the effectiveness of ammoniated bagasse in wicking oil from contaminated wetlands

Ammoniated bagasse is a plant-derived organic sorbent that can be used for capturing oil and for supplying slow-release nutrients to oil-degrading microorganisms. We investigated the oil-wicking behavior of this sorbent under various conditions for its effectiveness in remediating oil-contaminated wetlands. Abiotic microcosms simulating a wetland environment were used to assess the influence of sand particle sizes (20× 30 and 60× 80 U.S. mesh), degrees of oil saturation (25% and 75%), water table levels (on top of the clean sand layer, oiled-sand layer, and sorbent layer), and the presence of sorbent. Results indicated that oil wicking favors higher oil contamination, larger sand particle size, and low water coverage. Water coverage was the predominant factor limiting the effectiveness of sorbent. The most plausible explanation for this limitation was that sorbent captured more water than oil at higher water coverage.     

Survey of residential extremely-low-frequency magnetic field exposure among children in Taiwan

This survey estimated the extremely-low-frequency magnetic field (ELF-MF) exposure in households with children under the age of 7 years in Taiwan. To select a representative sample, we used the probability proportional to size sampling technique and simple random cluster sampling technique to select study districts in each city/county of Taiwan. A total of 40 districts were selected and all households with children aged less than 7 (n=4184) were visited and solicited for in-home measurements. Four trained interviewers carried out spot-measurements in rooms of each selected household during a two-year period. A questionnaire inquiring residential characteristics and nearby power facilities was also administered to a parent or caregiver. ELF-MF measurements were performed in a total of 2214 households (53% participation rate). Controlling for participation rate, the weighted overall mean magnetic field exposure was estimated at 0.121 (standard deviation 0.185) micro-Tesla (microT) (range 0.010-3.304 microT). Mean exposures were higher than 0.3 and 0.4 microT in an estimated 7.3% (n=159) and 5.4% (n=115) of the households, respectively. There was a substantial agreement between overall mean residential exposure and exposure measured in children's bedrooms. In a multivariate logistic regression model, we noted that buildings with advanced age, buildings for both residential and commercial uses, and buildings close to power facilities were more likely a to have mean exposure above 0.4 microT. Our survey results indicate that residential ELF-MF exposure is likely to be higher for children in Taiwan than for children in Europe and North America.     

Towards a control model for the highly cybernetic farming ecosystems

Abstract

A dynamic model based on the linear systems theory is developed in designing a highly cybernetic farming strategy to efficiently manage residuals generated in farm ecosystems. A linear cybernetic model would be used to describe the dynamic behavior of resource flow in the farm ecosystem in which the state variables are resource quantities, and the control variables are residual quantities. The controlled process is defined as the controlled management strategy change. Cybernetic mechanism shows the application of residuals as control measures have determinate effects on the controlled process as along as the farming system is observable and controllable in the control sense. To illustrate the model algorithm the idea is applied to simulate the dynamic response of residual phosphorus concentrations in an integrated pig/corn farming system located in the south Taiwan region. General results show that the residual phosphorous concentration is influenced by farming activities which are controlled by a system of gross input and net output parameters. This paper demonstrates using input‐output analysis technique that residuals generated in the farming system is the most important cybernetic variable, so that the proper management of residuals alone has the potential to maintain future productivity and sustainability.     

Biodegradable Chitosan-g-Poly(methacrylamide) Microspheres for Controlled Release of Hypertensive Drug

Chitosan-g-poly(methacrylamide) (CS-g-PMAAm) was synthesized by redox polymerization. The synthesized graft copolymers were used to prepare microspheres (MS) by water/oil (W/O) emulsion technique and cross-linked with glutaraldehyde (GA). Developed microspheres were encapsulated using enalapril maleate (ENAM) as a model drug (hypertension) and characterized by fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy. The physico-chemical properties of the microspheres were studied by calculating drug entrapment efficiency, and drug release kinetics. % of encapsulation efficiency (% EE) increased with increase in drug loading and methacrylamide (MAAm) content. The minimum % EE (65.2 ± 1.6) was observed in case of microsphere containing 40 % MAAm, 5 % ENAM and 10 mL glutaraldehyde. The release profiles indicate that formulation containing highest (10 mL) crosslinking agent microspheres has the slow release.     

Process plant safety information repository and support for safety applications

The consideration of safety of processing plants from design to operation involves many tasks. Different techniques and tools have been developed to assist in carry out those tasks. With the advances in computing technologies, both in hardware and software, there is the opportunity to bring together the vast amount of engineering, hazard and risk data and handle them in an efficient way to manage and improve safety throughout the life time of a plant. This paper proposes keeping such data in a process plant safety information repository which can be easily accessed by different safety-related tools to enhance the efficiency of safety identification and analysis tasks.     

Mutagenicity, genotoxicity and carcinogenic risk assessment of indoor dust from three major cities around the Pearl River Delta

The mutagenicity and genotoxicity of workplace dust including commercial office, secondary school, shopping mall, hospital, electronics factory and manufacturing plant in Hong Kong and settled house dust from Hong Kong, Shenzhen and Guangzhou were measured. Results indicated that indoor dust contained both frameshift and base pair substitution mutagens. Dust from manufacturing plant showed highest mutagenic potency on TA98±S9 and TA100±S9 activation, whereas, electronics factory showed highest genotoxicity with and without S9 activation. TA100 (-S9) mutagenic potency was significantly correlated with genotoxicity expressed as SOSIP (-S9) of workplace dust (r(2)=0.37, p<0.01). The total PAHs concentration of settled house dust from PRD ranged from 1.63 to 29.2μg/g. Linear regression analyses indicated that the PAHs likely accounted for about 45% of the TA98 with S9 mutagenic activity of workplace dust. TA98 (-S9) mutagenicity (r(2)=0.27, p<0.05) and SOSIP (-S9) of house dust (r(2)=0.41, p<0.01) were both significantly correlated with the number of inhabitants in the house. To achieve a more accurate cancer risk assessment, the oral bioaccessibility of B(a)A, Chry, B(b+k)F, B(a)P, D(ah)A and I(cd)P in different dust ranging from 1.3% to 17% was taken into account. Risk assessments indicated that about 26% of house dust samples resulted in unacceptable cancer risk (>1×10(-6)) for preschool children.     

Drought Resilience of the California Central Valley Surface‐Ground‐Water‐Conveyance System1

Abstract: A series of drought simulations were performed for the California Central Valley using computer applications developed by the California Department of Water Resources and historical datasets representing a range of droughts from mild to severe for time periods lasting up to 60 years. Land use, agricultural cropping patterns, and water demand were held fixed at the 2003 level and water supply was decreased by amounts ranging between 25 and 50%, representing light to severe drought types. Impacts were examined for four hydrologic subbasins, the Sacramento Basin, the San Joaquin Basin, the Tulare Basin, and the Eastside Drainage. Results suggest the greatest impacts are in the San Joaquin and Tulare Basins, regions that are heavily irrigated and are presently overdrafted in most years. Regional surface water diversions decrease by as much as 70%. Stream‐to‐aquifer flows and aquifer storage declines were proportional to drought severity. Most significant was the decline in ground water head for the severe drought cases, where results suggest that under these scenarios the water table is unlikely to recover within the 30‐year model‐simulated future. However, the overall response to such droughts is not as severe as anticipated and the Sacramento Basin may act as ground‐water insurance to sustain California during extended dry periods.     

Polybrominated diphenyl ethers and organochlorine pesticides in human breast milk from Massachusetts, USA

Concentrations of polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs; DDTs, HCHs, CHLs, and HCB) were measured in human breast milk samples collected across Massachusetts, USA, in 2004. Seventeen PBDE congeners were found in the samples, ranging in concentration from 0.06 to 1910 ng g(-1) lipid wt. BDE-47 (2,2',4,4'-tetraBDE), BDE-99 (2,2',4,4',5-pentaBDE), and BDE-100 (2,2',4,4',6-pentaBDE) were the major congeners detected in breast milk samples. Overall mean (+/-SD) concentrations of DDTs, HCHs, CHLs, and HCB were 64.5 +/- 75, 18.9 +/- 19, 32.4 +/- 36, and 2.3 +/- 2.2 ng g(-1) lipid wt, respectively. Concentrations of PBDEs were strongly correlated with concentrations of OCPs in the samples. Based on the concentrations of organohalogens and the intake rates of breast milk by infants in the United States, daily ingestion rates of contaminants were calculated. The median ingestion rates for PBDEs, HCHs, DDTs, CHLs, and HCB were 4.0, 212, 141, 44, and 5.79 ng kg(-1) body wt day(-1), respectively. The estimated daily intake of organohalogens by infants was compared with threshold reference values suggested by the United States Environmental Protection Agency (USEPA) and the Agency for Toxic Substances and Disease Registry (ATSDR), for calculation of hazard quotients (HQs). HQs for individual organohalogens and the sum of HQ for all organohalogens were calculated as HQ indices (HQI). The results suggest that one or more of the contaminants analyzed in this study exceeded the threshold reference values in at least 26% of the breast milk samples.