Health risk assessment of organochlorine pesticides with emphasis on DDTs and HCHs in abandoned agricultural soils

The aim of this study was to evaluate the consequence of changing land use from agriculture land to other use purposes with respect to OCPs non-cancer and cancer risk on human health, based on concentrations of DDTs and HCHs in soils collected from 55 locations representing 12 different land use types. There were no non-cancer risks of DDTs and γ-HCHs on adults and children, and there were very low cancer risks of DDD, o,p'-DDE, DDT, α-HCH, β-HCH, γ-HCH based on their total concentrations in all samples. Nonetheless, there were significant correlations of DDT to its metabolites (DDE and DDD) (r = 0.506 and r = 0.648) and DDE to DDD (r = 0.438) both at p < 0.01. OCP levels should be routinely monitored in different environmental media and food in order to verify whether there is fresh input. Their potential risks on human health should also be assessed.     

Spatial analysis and land use regression of VOCs and NO2 in Dallas, Texas during two seasons

Passive air sampling for nitrogen dioxide (NO(2)) and select volatile organic compounds (VOCs) was conducted at 24 fire stations and a compliance monitoring site in Dallas, Texas, USA during summer 2006 and winter 2008. This ambient air monitoring network was established to assess intra-urban gradients of air pollutants to evaluate the impact of traffic and urban emissions on air quality. Ambient air monitoring and GIS data from spatially representative fire station sites were collected to assess spatial variability. Pairwise comparisons were conducted on the ambient data from the selected sites based on city section. These weeklong samples yielded NO(2) and benzene levels that were generally higher during the winter than the summer. With respect to the location within the city, the central section of Dallas was generally higher for NO(2) and benzene than north and south. Land use regression (LUR) results revealed spatial gradients in NO(2) and selected VOCs in the central and some northern areas. The process used to select spatially representative sites for air sampling and the results of analyses of coarse- and fine-scale spatial variability of air pollutants on a seasonal basis provide insights to guide future ambient air exposure studies in assessing intra-urban gradients and traffic impacts.     

Prenatal diagnosis of Myhre syndrome with a heterozygous pathogenic variant in SMAD4 gene presented with thick nuchal translucency and cardiac abnormalities

Prenatal testing was performed in a 39-year-old Chinese pregnant woman referred for increased nuchal translucency measuring 5.7 mm. Non-invasive prenatal testing and SNP array study on amniotic fluid samples were normal. Whole exome sequencing (WES) was initiated further as the fetus had pericardial effusion of 1.2 mm, thickened myocardium over the right ventricular lateral wall and aberrant right subclavian artery. A detailed fetal echocardiogram also revealed persistent left superior vena cava and dilated coronary sinus at 20 weeks. From whole exome sequencing of the trio, a de novo heterozygous variant NM_005359.5(SMAD4): c.1499T>C (p.Ile500Thr) was detected. This pathogenic variant has been reported in the postnatal case cohort of Myhre syndrome. This condition is characterized by facial dysmorphism, intellectual disability, hearing loss, skeletal abnormalities and potential life threatening respiratory or cardiovascular manifestations. Termination of pregnancy was performed at 23 weeks. Small chins, pre-axial polydactyly, brachydactyly and clinodactyly were noted in the abortus. Ultrasound findings of increased nuchal translucency, thickened myocardium and pericardial effusion prompted further genetic evaluation for the prenatal diagnosis of Myhre syndrome by whole exome sequencing.     

Conceptual design of pressure relief systems

Conceptual design of pressure relief systems is an important stage in the design of a safe process plant. The conceptual design stage consists of the following steps: deciding on the location of pressure relief devices, selecting the general type of pressure relief device for each identified location, i.e. safety valve and/or bursting disc (rupture disc), or other relief device, and selecting the special features for the chosen device type. Some regulations, codes and standards, and a decision tree for the selection of a relief device have been described in the literature. This paper presents four decision trees that have been developed for the different steps in the conceptual design stage. Only positive pressure in pressure vessels is considered here.     

Leaching characteristics of paraffin waste forms generated from Korean nuclear power plants

Leaching tests of paraffin waste forms including boric acid, cobalt, strontium and cesium were performed to investigate the leaching characteristics of paraffin waste forms which had been generated in Korean nuclear power plants. The leaching tests were conducted according to ANSI/ANS-16.1 test procedure and the cumulative fractions leached (CFLs) of boric acid, cobalt, strontium and cesium were obtained. The compressive strength before and after the leaching test was measured for various waste forms with different mixing ratios of boric acid to paraffin. It was observed that boric acid and other nuclides immobilized within paraffin waste forms were congruently released and the leaching rates were influenced by reacted layer depth as the dissolution reaction progressed. A shrinking core model based on the diffusion-controlled dissolution kinetics was developed in order to simulate the test results. The CFLs and the leaching rates were well expressed by the shrinking core model and the cross-sectional view of specimen after the test demonstrated the applicability of this model with the shrinking dissolution front to the leaching analysis of paraffin waste forms.     

Pyrolysis of low-density polyethylene using synthetic catalysts produced from fly ash

Catalytic pyrolysis of low-density polyethylene (LDPE) was investigated using various fly ash-derived silica–alumina catalysts (FSAs). FSAs were prepared by a simple activation method that basically includes NaOH treatment of fly ash by a fusion method, followed by an aging process. A series of LDPE pyrolysis experiments was conducted and the catalytic performance of FSAs was assessed in terms of the degradation temperature and the simulated boiling point distribution of the liquid products. The effects of synthesis conditions such as NaOH/fly ash weight ratio and aging time were examined by X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET) surface area analyzer, and scanning electron microscope to clarify the controlling factors affecting the catalytic activity. To obtain catalyst with high activity, it is necessary to produce sufficient silica and alumina species that can be easily co-precipitated into solid acid catalyst by destruction of the fly ash structure and to optimize the activation time for catalyst synthesis to prevent the transformation into inactive phases. The catalytic performance of FSA obtained from optimal conditions was equivalent to that of commercial catalysts, demonstrating the effectiveness of the catalyst.     

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.     

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.