An assessment of chemical contaminants in the marine sediments of southwest Puerto Rico

This report summarizes the results of a characterization of chemical contaminants in the sediments in southwest Puerto Rico. The report is part of a project to integrate various analytical specialties to assess linkages between chemical contaminants and the condition of coral reefs. In this phase of the project, over 120 chemical contaminants were analyzed in sediments collected, including a number of organic (e.g., hydrocarbons), inorganic (e.g., metals), and biological (bacterial) compounds/analytes. The report also provides a preliminary analysis of the association between sediment contaminants and coral species richness. Overall, the levels of chemical contaminants in the study area between Guanica Bay and the town of La Parguera were fairly low. At most of the sites sampled, particularly adjacent to the town of La Parguera, concentrations of organic and inorganic contaminants were below the median values from NOAA’s National Status and Trends Program, which monitors the Nation’s coastal and estuarine waters for chemical contaminants. Elevated levels of a number of contaminant classes were seen at the two sites sampled within Guanica Bay. An initial analysis of modeled PAH (hydrocarbon) data and coral species richness (reef building species) indicated a strong negative correlation between the presence of PAHs in the sediments and coral species richness. Additional work is needed to assess possible reasons for this observed pattern. (PDF contains 126 pages)

Fiber-Borne and Water-Borne Chemical Contaminants

The main idea behind this thesis is to work with recycled paper because this is the latest trend due to the environment. Therefore, after checking into an aspect that has little research completed, the idea of the effects of chemical contaminants on sizing of paper, AKD in particular, was developed. To allow for expansion on this thesis topic, another student will be looking at the effect of chemical contaminants on sizing of the recycled paper. The experiment contained water-borne chemical contaminants and fiber-borne chemical contaminants. Four different chemical contaminants were used including retention aid, defoamer, biocide, and wet strength. The water-borne chemical contaminants were added with the sizing and made into handsheets on the Noble and Wood. The fiber-borne chemical contaminants were added to the pulp, and washed and dried. Then the contaminated pulp was redispersed, sizing agent added and made into handsheets. The tests conducted were Hercules size test and contact angle. The results for the water-borne chemical contaminants mostly followed the expected results. The retention aid helped the sizing while the defoamer, biocide, and wet strength hindered the sizing. For the fiber-borne chemical contaminants, the retention aid, defoamer, biocide, and wet strength all increased the sizing above the control level. The contact angle determined that small amounts of AKD give high contact angles, showing full sizing. Plus, the water-borne chemical contaminants had high contact angles for the high HST values, and the fiber-borne chemical contaminants gave high contact angle for the low HST values. The objective behind this thesis was to determine if the chemical contaminants would adhere to the fiber before the AKD was added, and therefore help or hinder the sizing effect

Contamination control in hybrid microcircuit modules

The influence of chemical and particulate contamination upon the reliability and service life of hybrid microelectronic systems is documented. Several coating systems used include the parylene and Dow Corning silicone (DC90-711). These passivating coatings have potential for decreasing the degradation caused by particulate contaminants in hybrid systems as well as the possible deleterious effect of trapping chemical contaminants which have long term degrading influences upon the performance of the system. The reliability of a representative hybrid microcircuit is enhanced by the coating process

Airborne trace contaminants of possible interest in CELSS

One design goal of Closed Ecological Life Support Systems (CELSS) for long duration space missions is to maintain an atmosphere which is healthy for all the desirable biological species and not deleterious to any of the mechanical components in that atmosphere. CELESS design must take into account the interactions of at least six major components; (1) humans and animals, (2) higher plants, (3) microalgae, (4) bacteria and fungi, (5) the waste processing system, and (6) other mechanical systems. Each of these major components can be both a source and a target of airborne trace contaminants in a CELSS. A range of possible airborne trace contaminants is discussed within a chemical classification scheme. These contaminants are analyzed with respect to their probable sources among the six major components and their potential effects on those components. Data on airborne chemical contaminants detected in shuttle missions is presented along with this analysis. The observed concentrations of several classes of compounds, including hydrocarbons, halocarbons, halosilanes, amines and nitrogen oxides, are considered with respect to the problems which they present to CELSS

Analysis of sorbents and catalysts used during a 90-day manned test

Chemical analysis of organic trace contaminants in simulated space station atmospheres desorbed from molecular sieve, silicon gel, and catalyst bed

Chemical contaminants of indoor air quality (IAQ): a review

Chemical contaminants are mostly not easy to determine in terms of their source and effect. However, the chemical contaminants in indoor air were identified as gases and vapors (inorganic and organic), and particulates matter [1]. In the indoor air environment, the chemical contaminants access from outdoor or develop within the building. In addition, chemical contaminants can originate anywhere in a facility in excess of recommended amounts [2]. Nowadays all building has some collection of chemical around with potential to become a contaminant in the air. According to DOSH, 2010 [3] stated that the main factor chemical pollutants usually found in the indoor air are carbon monoxide, formaldehyde, respirable particulates, total volatile organic compounds (TVOC). This chapter also presents the basic knowledge of organic and inorganic pollutant as chemical contaminants of Indoor Air Quality (IAQ)

Analytical technique characterizes all trace contaminants in water

Properly programmed combination of advanced chemical and physical analytical techniques characterize critically all trace contaminants in both the potable and waste water from the Apollo Command Module. This methodology can also be applied to the investigation of the source of water pollution

Hybrid in vitro diffusion cell for simultaneous evaluation of hair and skin decontamination: temporal distribution of chemical contaminants

Most casualty or personnel decontamination studies have focused on removing contaminants from the skin. However, scalp hair and underlying skin are the most likely areas of contamination following airborne exposure to chemicals. The aim of this study was to investigate the interactions of contaminants with scalp hair and underlying skin using a hybrid in vitro diffusion cell model. The in vitro hybrid test system comprised “curtains” of human hair mounted onto sections of excised porcine skin within a modified diffusion cell. The results demonstrated that hair substantially reduced underlying scalp skin contamination and that hair may provide a limited decontamination effect by removing contaminants from the skin surface. This hybrid test system may have application in the development of improved chemical incident response processes through the evaluation of various hair and skin decontamination strategies.Peer reviewedFinal Published versio

Availability and information needs in the chemical contaminants domain – PortFIR assessment

Chemical contaminants (Chc) can be naturally present and/or be introduced in food and feed as result of the various stages of its production, processing and transport and/or due to environmental contamination. The analysis of Chc laboratory data allows to generate information for continuous improvement of food safety and protection of public health. In order to define priorities for development of the Contaminants Database of the Portuguese Food Information Resource (PortFIR), it was decided to identify and assess the availability and information needs on food and feed Chc of the main Portuguese stakeholders in the area.N/