Organotin compounds are ubiquitous contaminants in the environment. The high biological activity of some compounds toward aquatic organisms lead to deleterious impacts in aquatic ecosystems. Here, the aquatic ecotoxicology of organotins is reviewed based on a multidisciplinary approach involving environmental chemical, toxicological, and ecological aspects. Basic results were obtained both with field and laboratory studies, and some of the most important recent results and conclusions are critically reviewed. The contamination of and fate in aquatic systems is reported and linked with effects at different levels of biological organization. Major emphasis is placed on the development of a concept of ecotoxicology that encompasses not only effect assessment alone, but also integrates environmental chemistry with aquatic toxicology. Thereby, the influence of speciation for bioavailability, basic modes of toxic action, and aquatic toxicity are discussed. This case study on organotins allows to a certain extent generalizations to ecotoxicology in general.

Ecotoxicology of organotin compounds.

The removal of dyes from textile wastewater: a study of the physical characteristics and adsorption mechanisms of diatomaceous earth

This public health statement tells you about manganese and the effects of exposure to it.The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites are then placed on the National Priorities List (NPL) and are targeted for long-term federal clean-up activities. Manganese has been found in at least 869 of the 1,699 current or former NPL sites. Although the total number of NPL sites evaluated for this substance is not known, the possibility exists that the number of sites at which manganese is found may increase in the future as more sites are evaluated. This information is important because these sites may be sources of exposure and exposure to this substance may harm you.When a substance is released either from a large area, such as an industrial plant, or from a container, such as a drum or bottle, it enters the environment. Such a release does not always lead to exposure. You can be exposed to a substance only when you come in contact with it. You may be exposed by breathing, eating, or drinking the substance, or by skin contact.If you are exposed to manganese, many factors will determine whether you will be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with it. You must also consider any other chemicals you are exposed to and your age, sex, diet, family traits, lifestyle, and state of health.

Toxicological Profile for Manganese

Amino acid analysis : Hydrolysis, ion-exchange cleanup, derivatization, and quantitation by gas—liquid chromatography

Nanoparticles (NPs), due to their unique physical and chemical properties, especially their minute particle size (⩽100 nm), find applications in numerous industrial, commercial and consumer products. After their end-user applications, these NPs find their way into the environment and food products. The NPs so discharged need to be quantified accurately to determine their toxicity and exposure levels. At this time, there is a need to develop a unified method for their determination. There are plenty of techniques available in the market that were initially used for colloidal particles (e.g., microscopy, spectroscopy and the recent addition of magnetic resonance), but each of these techniques has a certain degree of uncertainty. Further, sample homogeneity, sample preparation, instrument-operating procedures, and statistical practices are likely to add to the complexity of the problem. In this context, this review attempts to understand the widely-used light-scattering techniques, including their theory, practice and real-world use in determination of NPs in environmental and food applications.

Measurement of nanoparticles by light-scattering techniques

Signals from a dual-channel flame photometric detector (FPD) can be digitaly processed by a conditional-acces algorithm (CONDAC) to yield chromatograms that are specific (meaning infinitely selective) for any chosen FPD-active element.

Elemental specificity in dual-channel flame photometric detection of gas chromatographic peaks

A simple dual-channel detector was constructed from a regular FID and a spectrometer. The response of this system was studied with compounds of iron, lead, and tin, as well as phosphorus and sulfur, under air-rich and hydrogen-rich conditions. Both emission and ionization responses can be used to determine the metals in the nanogram and picogram ranges, respectively; while the response to carbon is repressed by several orders of magnitude. Despite its obvious wealth of sensitive and selective detectors, gas chromatography is still in need of some improvement in the area of organometallics. The determination of metals as chelates, the detection of volatile environmental contaminants, and the monitoring of agricultural and industrial chemicals would all benefit from detection systems specific for certain hetero-elements. This paper describes studies on a simple dual-channel GC detector based on the ionization and emission processes occurring in a hydrogen flame. The small flames of the air-rich FID and the hydrogen-rich Brody-Chaney detector (1) have been remarkably successful in their respective areas; yet, one may justifiably argue that neither should be particularly applicable to the detection of typical metals. The air-rich flame can be made selective to phosphorus (and, to a lesser degree, nitrogen, chlorine, bromine, and iodine) by the addition of alkali-but responses to typical metals are not particularly noteworthy in this ionization mode (2). The hydrogen-rich flame is very sensitive to phosphorus and sulfur (I), also to boron (3), in the photometric mode-but this mode depends on molecular emission bands which are prevalent in (or especially above) “cool” flames (POH, Sz, BO).

Walter A. Aue

Papers

Elemental specificity in dual-channel flame photometric detection of gas chromatographic peaks

Selective determination of heteroorganics by a dual-channel detector based on flame conductivity and emission

Selective detection of organometallics in gas chromatographic effluents by flame photometry

A search for amino acids in Apollo 11 and 12 Lunar fines

Novel flame photometric detector for gas chromatography based on counter-current gas flows.