No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

A time series study was conducted to investigate the association between variations in daily levels of air pollution and health effects in the city of sao Paulo, Brazil. This study was prompted by positive associations reported in other time series studies, principally in North AmeriE:a and Europe, and preliminary results from some limited analyses reported for sao Paulo. Its aims were to examine specific causes of mortality and hospital admissions, to identify more vulnerable subgroups defined in terms of age, to assess the role of socio-economic conditions in modifying the association and to detail the impact of other potential risk factors, especially meteorological. Daily measurements of air pollutants (PM10, S02, N02, 0 3 and CO) for 12 monitoring stations across the city and several meteorological variables, along with daily counts of mortality for all ages during 3 years and hospitalisations for children during 23 months were available. The time series models used Poisson regression analysis and were adjusted for effects of trend, cyclical patterns (including season), weekday, holidays, meteorological factors, and autocorrelation. Increases in PM10 and S02 were associated with a 3-4% increase in daily deaths for all causes in the elderly (results are presented for an increase from the 10th to the 90th centile of pollution measurements). Cardiovascular deaths were additionally associated with CO (4% increase). Respiratory deaths in the elderly showed higher increases (6%) associated with PM10• No significant effects for children's mortality were observed. Nevertheless, respiratory or pneumonia hospital admissions for children showed significant increases associated with 0 3 (5-8%), N02 (9%), and to a lesser extent with PM10 (9%). There was a significant trend of increasing risk of death according to age with effects only evident for older subjects. However, this age effect was more evident for all cause mortality. There was a weak suggestion of larger effects on mortality for areas economically more affluent. Some indication was found of a harvesting effect occurring in the mortality and hospital admission series in sao Paulo. Results are broadly consistent with those previously reported but somewhat smaller in magnitude. In contrast with an earlier preliminary analysis in Sao Paulo, there were no effects on mortality for children. However, new analyses for hospital admissions indicated that children are at an increased risk of non-fatal illness in relation to air pollution.

An opportunistic study was carried out in central Mexico, where one of the world's largest wastewater reuse schemes for agricultural production is located. This scheme provided a unique opportunity to assess the health impact of exposure to wastewater of different qualities on intestinal parasitic infections and diarrhoeal diseases. The central objective of the study was to evaluate the effect of hydraulic retention on reducing the health risks associated with wastewater use. Exposure groups were defined according to eligibility procedures and to the quality of irrigation water. Microbiological quality was measured using nematode eggs and faecal coliforms as indicators. The exposure groups involved households: a) exposed to untreated wastewater; b) exposed to wastewater retained in a single reservoir; c) exposed to wastewater which had passed through two reservoirs in series, and been retained for some time in both; and d) nonwastewater-exposed households (controls). The study outcomes included risk of Ascaris lumbricoides, Entamoeba histolytica and Giardia lamblia infections, as well as the risk of diarrhoeal diseases. The study design was based on two cross-sectional surveys (rainy and dry seasons), and the analyses focused on both comparison of risks between the different exposure groups as well as the identification of at-risk groups. The two surveys involved different intermediate groups - (b) and (c) above - and the main purpose was to assess the effects of single versus double hydraulic retention. They are distinguished mainly for this purpose, rather than the evaluation of possible seasonal fluctuations of the study outcomes. Other variables (i.e. socioeconomic, hygiene and sanitation) were analysed as confounders using a multivariate model. In young children the prevalence rates of A. lumbricoides infection were considerably higher in the raw wastewater group (13.7%), and lower prevalences were observed with decreasing exposure (11.8% in the single reservoir group, 3.3% in the double reservoirs group, and 0.6 - 2.5% in the control group). A high prevalence rate of G.lamblia was observed in children (17 - 20.5%), but no association with untreated wastewater was found. The prevalence rates of E. histolytica infection in children from the various exposure groups ranged between 4.8 - 7.0%, but were considerably higher in older individuals: 15.7 and 16.5% in the two surveys among the raw wastewater group, compared with 13.2% and 14.7% respectively in the controls. In addition, a high prevalence of diarrhoeal diseases (two-weeks recall period) was found in the rainy season, particularly in young children from the raw wastewater exposure group, and lower prevalences were observed with decreasing exposure (29.0% in the raw wastewater group, 26.8% in the two reservoirs group, and 23.0 % in the control group, respectively). The overall prevalences of Cryptosporidium parvum and Trichuris trichiura infections were unexpectedly low (below 1% and 4%, respectively), and excluded from further consideration. The intensity of A. lumbricoides infection was evaluated in a parallel study, and is not reported here. The main findings of the present study can be summarised as follows: - Cropland irrigation with raw wastewater was strongly associated with A. lumbricoides infection in farmworkers and their families, with a risk of diarrhoeal diseases, and with a small but significant risk of E. histolytica infection in individuals aged over 5 years. - The differences observed in the prevalences of A. lumbricoides infection and diarrhoeal diseases were similar in both seasons, but the prevalences in the control group were lower in the dry season; thus, the relative effect of wastewater use was greater in the dry season. - Retention of wastewater in two reservoirs in series (2-6 months) reduced substantially the risk of A. lumbricoides infection, and to a lesser extent the risk of E. histolytica infection, and possibly the risk of diarrhoeal diseases in young children. - Retention of wastewater in a single reservoir (1 - 7 months) did not reduce the risk of A. lumbricoides or E. histolytica infection, but may reduce the ri sk of diarrhoeal diseases in children by 20%. - No association between exposure to raw wastewater and infection with G. lamblia was detected in this research. - Parasitic intestinal infections and diarrhoeal diseases showed significant associations with variables describing personal and domestic hygiene, basic sanitation and socioeconomic characteristics. These results are discussed in relation to local regulations and health protection measures, as well as in light of the WHO 1989 revised guidelines for restricted crop irrigation.

Benzene is a leukaemogenic and mutagenic agent, which may pose a risk to the general public even at low levels of exposure. Since petrol fuel contains a high concentration (1-5%) of benzene, there is the potential for exposure to man during car journeys. The main aim of this study was to develop and validate a sensitive method to detect urinary t,t-muconic acid (uMA) following low level environmental exposures to benzene. Subjects potentially exposed to benzene were divided into petrol (n= 9) and diesel groups (n= 7). The control group (n=14) consisted of individuals who were not exposed to benzene inside the car. The uMA method developed during this study involved butanol extraction instead of the traditional solid phase extraction followed by DV (259nm) detection. The method was reasonably precise (CV=1.5%) with >80% recovery from urIne. Air samples were collected on charcoal tubes and analysed for benzene, toluene, ethylbenzene, and xylenes by GCMS following extraction with purified carbon disulphide. The benzene concentration of ambient air samples taken from inside the cabins of petrol fuelled cars (7.5 ppb) was about triple that found from diesel-fuelled cars (2.6 ppb)(P=O.Ol). The uMA of volunteers exposed to petrol increased (p<0.01) post-sample in compared to pre-exposure level (0.66mgMA/gCr and 0.38mgMA/gCr, respectively). There was no increase in uMA for volunteers exposed to diesel. The uMA level of samples collected from individuals 2h-7h after exposure to petrol showed a significant association with the air benzene (p=0.012) and toluene (p=0.042) concentrations taken inside the car cabins. Half of the 24h-profiles of individuals exposed to petrol had at least one urine with 1 mgMA/gCr or higher, while all of the profiles of controls were below 1 mgMA/gCr. The technique developed in this study for the determination uMA showed promise as a tool for monitoring levels of benzene arising from low-level environmental exposures to petrol.