Indoor and outdoor formaldehyde concentrations in homes in residential areas in Greater Cairo

Indoor and outdoor measurements of formaldehyde were conducted at seven flats located in residential areas in Greater Cairo, during spring and summer seasons 1999. The mean daytime formaldehyde concentrations in kitchens, bedrooms and living rooms were 89, 100 and 100 ppb, respectively, in the seven flats. Significant positive correlations were found between the concentrations of formaldehyde found in these three rooms. On the other hand, no significant differences were found between the mean formaldehyde concentrations in these three rooms. The maximum mean concentration of formaldehyde (147 ppb) was recorded in a new flat, while the minimum concentration (43 ppb) was observed in an old flat. The maximum hourly and daytime concentrations were 350 and 225 ppb, respectively. Air temperature, relative humidity and the age of the flat are factors affecting the emission and concentration of formaldehyde. The maximum indoor and outdoor formaldehyde concentrations were recorded during the summer season. During the spring, 38% of the samples indicated that the concentration of formaldehyde in the seven flats exceeded 0.1 ppm, the American Society of Heating, Refrigerating, and Air Conditioning Engineers' (ASHRAE) standard; in the summer, this figure increased to 53%.     

Evaluation of airborne lead in the welding working environment

Manual and automatic welding machines (which use leaded alloys) are considered to be important sources of the emission of lead fumes into the general air of the working environment. Three workplaces at a television factory were selected for the present study, to determine the control class of the working unit. The concentrations of conventional measurements ("A" sampling points) were lower than the administrative control level (statutory standard of lead, 150 microg m(-3)), whereas the maximum concentration of 264.1 microg m(-3) ("B" sampling point) was higher at one working unit than the administrative control level. However, the control classes varied between class III (bad) and class I (good).     

Young northern pike,yellow perch and crayfish as bioindicators in a mercury contaminated watercourse

Young-of-the-year and yearling northern pike (Esox lucius), yearling yellow perch (Perca flavescens) and adult crayfish (Orconectes virilis) were collected in the mercury-contaminated Wabigoon/English/Winnipeg River System, Ontario, and analyzed for total mercury. Analysis of mercury concentrations in these organisms produced consistent geographical trends; i.e. mercury concentrations in biota downstream of Dryden > English River system > Winnipeg River system > control sites. In the Wabigoon River system the bioavailability of mercury increases with distance downstream of the historical point source. Mercury concentrations in the biota studied were highly correlated with mercury concentrations in fish species which are of sport and commercial interest. The locations where young fish obtain their bodyburdens are known typically within 100 m. The biota studied compare favourably with the criteria proposed by Phillips (1980) as prerequisites for biological indicators. The wide distribution of young pike, perch and crayfish in North America, Europe and Asia may enhance their appeal as biomonitors.The views expressed are those of the authors and do not necessarily reflect the views of the Ontario Ministry of the Environment. No endorsement should be inferred.     

Temporal variation in a coral reef community at Pattaya Bay,Gulf of Thailand

Changes in the fringing coral reef community of a small island (Ko Nok) at Pattaya Bay, Gulf of Thailand, were examined at the beginning and at the end of a 3-year period using 7m×7m permanent quadrats for benthic organisms, and visual census along 100m transects for fish. The coral community was dominated by Porites lutea in terms of colony number and areal cover throughout the period. Variations in the community structure parameters on opposite sides of the island indicated increasing dissimilarity with time. Little variation in live coral cover was noted, but colony number and species diversity declined on both sides. The abundance of edible fish species dropped while that of non-edible species increased over the 3-year period, indicating selective removal of the former category through fishing. Impacts from both human and natural influences are implicated in these changes.     

Organochlorine contaminants in seabird eggs from the Pacific coast of Canada, 1971–1986

Eggs were collected from seven seabird species at colonies on the British Columbia coast from 1983 to 1986 and analyzed for organochlorine contaminants. Total PCB levels (wet weight) were highest in double-crested cormorants (Phalacrocorax auritus) from the Fraser estuary (2.91 mg kg^-1) and the Strait of Georgia (3.79 mg kg^-1). Highest DDE levels were in fork-tailed storm-petrels (Oceanodroma furcata) from the Queen Charlotte Islands (1.68 mg kg^-1). Organochlorine levels were generally lower in eggs from the mid 1980s than in those collected in the early 1970s. Organochlorine levels in Pacific alcids and hydrobatids foraging in offshore locations were compared to those in the same or ecologically similar species from the Canadian Atlantic coast. DDT- and HCH-related compounds were higher in Pacific populations while levels of dieldrin, oxychlordane, and HCB were generally lower. With the exception of -HCH, levels of all measured organochlorines were lower in cormorants breeding in the Fraser River estuary than in cormorants from the St. Lawrence River estuary on the Atlantic coast.     

Information needs for marine pollution studies

Information needed for the resolution of environmental problems is a commodity with an economic value. The minimum necessary information implies minimal costs. The formulation of the information is considered for the case of biocides that can disrupt marine ecosystems.     

Organochlorine and mercury residues in Swainson's and ferruginous hawk eggs collected in North and South Dakota, 1974–79

Residues of organochlorine pesticides, polychlorinated biphenyls (PCBs), and mercury were measured in eggs of Swainson's hawks (Buteo swainsoni) and ferruginous hawks (B. regalis) collected in North and South Dakota during 1974–79. DDE was the most common compound detected in the eggs, but residues were below levels known to have adverse effects on reproduction. Other organochlorine compounds and mercury were found at low levels. Eggs of ferruginous hawks tended to contain more compounds with higher residues than eggs of Swainson's hawks.     

The characteristics of size distribution of suspended particulates in the air for sulphates and selected metals in different areas and seasons

The characteristics of the distribution of particles by size were investigated for sulphates and selected metals (Pb, Fe, Mn, and Cu) in the air in two urban and an industrial area during the winter and summer periods using an Andersen cascade impactor.In the case of metals, but not sulphates, the character of the area affected the value of mass median diameter. Lowest values were obtained in a sparsely populated urban area, whereas in a densely populated urban area and in the industrial area the values were higher.In the industrial area a high correlation coefficient was found between sulphate and manganese, and between sulphate and lead, as well as a high value of the equivalent Mn²⁺/SO _inf4 ^sup2- ratio for the total sample. It may therefore be assumed that in the industrial area manganese produces a catalytic effect on SO₂ conversion to sulphate. Among the investigated metals lead stands out as a dominant cation which binds to the sulphate ion in the industrial and densely populated areas.     

Population monitoring for genetic damage induced by environmental physical and chemical agents

The short-term tests performed in vitro on different systems, from phage to human cells, or in vivo, on laboratory animals, allow only a qualitative estimate of the action of mutagenic agents, and the extrapolation of such experimental results to man may encounter many difficulties.Direct biomonitoring of populations exposed to chemicals could represent a more realistic approach for an evaluation of the hazards to man. Certain methods are still under development. Nevertheless, other ones can already by used routinely, e.g. the cytogenetic observations on peripheral blood lymphocytes and the Ames test for mutagenic substances in urine, and can provide useful suggestions how to set threshold limits for chemical substances encountered in the working environment.