The aim of wood preservation is to extend the service life of non-durable wood species under conditions conducive to destruction by wood-destructing organisms. The efficacy of any preservative treatment depends, among other factors, on the concentration of the preservative in the treated zone and the depth of penetration. Wood preservatives are often complex mixtures of toxic chemicals which in most cases penetrate the wood differentially. The paper discusses the use of absorption spectrophotometer to determine not only the amount of preservative in a particular section of the wood but also the amount of the various toxic components in various parts of the treated wood.

Marked differences were observed in proximate biochemical compositions of the skin and muscle of white pomfret. The skin showed comparatively higher content of extractable lipids and was more susceptible to radiation-induced oxidative changes like development of rancid odours and yellow discolouration than the muscle. Irradiation of skin samples under vacuum suppressed these changes. The present paper also reports on the efficacy of vacuum packaging in controlling oxidative rancidity and yellow discolouration in white pomfret skin subjected to irradiation and subsequent storage at 0-2°C. | Pt. 2: Precursors of yellow discolouration in irradiated white pomfret (Stromateus cinereus). Fishery Technology, 9(1), pp. 17-24. - Pt. 3: Storage properties of white pomfret (Stromateus cinereus) fillets. Fishery Technology, 9(1), pp. 25-30.

In the absence of analytical methods, the half-life of biological activity of a chemical can be estimated by bioassays. The methods presented require the determination of the LC50 values (concentration providing 50% mortality) for organisms in aged solutions containing unknown residual concentrations, and concurrent tests of solutions containing known concentrations. The half-life of biological activity is determined by plotting (1) the percent concentrations remaining in aged solutions or (2) the deactivation indices against aging time on cyclic semilogarithmic graph paper. These methods could be used also to determine the half-life of antimycin at different pH's, temperatures, and light intensities, the factors thought to influence the toxicant's efficacy. The methods are not limited to fish and fish toxicants.

Coal mining produces a variety of environmental problems -- acid drainage, sedimentation, surface subsidence and surface scars. The study reviews the response of legal institutions to those problems in Maryland, Ohio, Pennsylvania and West Virginia. Technological and economic concerns are also taken into account. The study discusses the antecedents of today's Appalachian coal industry and the environmental problems it has created. It examines the way in which the property system allocates rights in coal and coal lands, the efficacy of litigation and present laws and regulations for preventing environmental damage, and constitutional limitations on the ability of states to effectively respond to the problems. A case study of the economics of the Maryland coal industry is also presented. Model legislation giving the states the necessary powers to respond to environmental problems, is proposed.

Leaf-feeding mites are one of the most J severe pest problems for growers of deciduous fruits and nuts in California. The mites primarily responsible for these problems include the European red mite, Panonychus ulmi (Koch), the two-spotted mite, Tetranychus urticae Koch, and the Pacific mite, T. pacificus McGregor. Control of these and other species of mite pests has depended upon the use of pesticides that may be harmful to non-target species of insects and mites, and may also lose their efficacy against target species because of a build-up of resistance. In an attempt to find those materials that are effective against the target species, and the least harmful to non-target species, new chemicals are continually being evaluated for their effect on both pest and beneficial species of mites and insects. This report presents the results of field trials of new, but as yet unregistered, pesticides that were evaluated as miticides on the European red mite and Pacific mite during 1971.

A comparative trial was made of five fire retardants, viz. (a) a 60 : 40 mixture of borax and boric acid; (b) a Na-silicate solution of 40 deg Be density (defined); (c) a 70 : 30 mixture of (b) and kaolin; (d) a 70 : 30 mixture of (b) and limestone; and (e) concentrated Na-silicate solution (applied after preliminary impregnation with Na silicate diluted with water in the ratio 1 : 1). The timbers treated (by procedures described) were Nauclea diderrichii, Khaya ivorensis, Chlorophora excelsa and Entandrophragma cylindricum. The results showed that: the efficacy of the fire retardants tested was directly related to the quantities used; (a) gave moderate fire resistance at 42-49 kg/m3 retention; two coatings of (b), (c) or (d) gave satisfactory protection; (e) was highly effective, and when used on external timber should resist severe weathering for 1-2 years; and N. diderrichii was the most and C. excelsa the least fire-resistant of the four timbers. It is concluded that (a) can be recommended as a fire retardant for interior use and (e) for external use, while (b), (c) and (d) are suitable where only temporary protection is required or where the protective coating can be renewed frequently.