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A comparative study has been made of the sensitivity of the acute Daphnia magna immobilization test and the Daphtoxkit F™ magna microbiotest for 30 household products of different categories (cleaning and degreasing products used in the industry, wash products for large laundries, household cleaning products and products for hygienic and personal care). The study revealed that the 48h EC50’s encompassed 3 orders of magnitude (from a few mg/1 up to 1000 mg/1) with large sensitivity differences between products “use” category. Median toxicities were very similar for the conventional D. magna test and the Daphtoxkit F™ microbiotest. Regression analysis revealed the excellent correlation between the 2 test methods (r value of 0.971). This study confirms the analogous findings made in several other recent studies with a variety of chemicals, wastes and natural samples and further validates the usefulness of the new "culture free" microbiotest technology, not only from the point of view of sensitivity, but also practicality and costefficiency.

Rad objašnjava potrebu primjene biotestova radi zaštite voda

Određena je biološka razgradnja četiri uzorka maziva primjenom Sturm metode u kojoj se mjeri ugljik(IV)-oksid nastao potpunom razgradnjom organske tvari. Dva maziva sadrže biljna ulja, a druga dva sintetičke estere. Pokusi su provedeni izravnim dodavanjem maziva u reakcijsku bocu uz intenzivno miješanje. U nekim je pokusima usporedno određena biološka razgradnja dodatkom maziva prethodno dispergiranog u ultrazvučnoj kupelji. Iz postignutih rezultata se može zaključiti da je primijenjena Sturm metoda prikladna za određivanje brzine i stupnja potpune biološke razgradnje maziva, što je jedan od osnovnih pokazatelja ekološke prihvatljivosti tih u vodi slabo topljivih tvari. Pri razmatranju rezultata treba uzeti u obzir da se tako intenzivno miješanje i dispergiranje kakvo se postiže u laboratoriju ne može očekivati u prirodi, pa se za što bolju procjenu biološke razgradnje maziva u vodenom okolišu preporuča usporedno određivanje izravnim dodatkom maziva na mješaču i prethodnim dispergiranjem u ultrazvučnoj kupelji.

Rad opisuje moguć utjecaj sredstava za čišćenje i odmašćivanje na onečišćenje voda

The paper compares the two tests related to ecotoxicological routine procedures

Few counties in the United States have played a more vital role in twentieth-century metropolitan affairs than Los Angeles County. The years from 1910 to World War II saw the county government enter into certain types of service contracts with cities, organize various special-purpose districts, and provide a wide range of services to unincorporated areas.' Rapid population growth in the postwar decade caused many outlying communities to seek incorporation as a means for control of land use policies. Fearful that new incorporations would reduce the size and quality of its service establishment, the county offered a plan by which cities could contract with it for a full set of municipal services. Suburban Lakewood embraced the scheme and provided a model for newly organized cities seeking to circumvent the bureaucracy and costs of local government. The Lakewood plan established a pattern of public decision-making that departed in important ways from urban governmental structure not only in California but also in American metropolitan areas generally. In so doing, it raised serious questions of local control, accountability, responsiveness, and metropolitan obligations. Resolving these issues demanded concessions on the part of both the county and Lakewood plan communities. Thousands of people migrated to southern California during the post World War II decade, for defense-related jobs in aircraft, aerospace, electronics, and scientific instrument industries. Los Angeles County's population rose from 4,151,000 in 1950 to 6,000,000 by 1960.2 Federal Housing Authority mortgage insurance and liberal loans from the Veterans Administration that required only small down payments enabled middle-class and workingclass families to buy homes in suburban districts. Applying mass production techniques to the housing industry, large-scale developers subdivided farmland throughout the county and built standardized units on tracts of fifty, a hundred, and several hundred acres.3 Lakewood was the most spectacular project. Developer Louis H. Boyar purchased 3,3 75 acres of farmland adjacent to Long Beach in 1950. His company, with the help of professional city planners, laid out a community of 17,500 homes for an ultimate population of more than 70,000. By 1953 Lakewood Park, advertised as 'The City as New as Tomorrow," had streets, side