Impact of long-term pesticide applications on some soil biological parameters.

The soil oxidative and anaerobic processes, as well as, the microbial biomass were followed during three years in a cotton farm (Tatuí) where the recommended pesticides have been used for several years, and in an experimental field (São Paulo) treated first time with the same pesticides. The oxidative process was monitored by the dehydrogenase (DHA)-activity using triphenyltetrazolium chloride (TTC) as substrate. The anaerobic process was followed by the iron-oxide reduction, and the microbial biomass was estimated by the substrate (glucose)-indiced respiration. Increases in DHA-activity and in the microbial biomass occurred only in the farm soil, with concomitant decreases in iron-reduction. In the experimental field soil, the increases in DHA-activity were followed only by decreases in iron-reduction. Soil characteristics were the determining factor for different biological parameters after pesticide inputs. All the pesticides produced at least one clear but transient effect.

An ecological study of the correlation between diet and tumour mortality rates in Italy.

Cancer is said to be due to nutrition in 35 cases out of 100, ranging from 10 to 70% by sites. Saturated fats show a positive relationship with cancer, while vitamins, vegetables and cereals show a negative relation with it. This work was aimed at studying the relationship between nutrition and cancer in different Italian areas. Cancer mortality rates collected in 94 National Health units over the period 1980-82 have been correlated with the average food consumption of individuals registered in the same units. All the nutrient groups have shown evidence of a correlation between nutrient intake and mortality rates. Fats, animal proteins and saturated fatty acids showed the strongest positive correlations; vegetable proteins, fibre, carbohydrates, oleic acid, vitamins C and B1 gave negative correlations. Thus, it can be concluded that (a) this ecological analysis has confirmed previous hypotheses concerning the role of vegetables in cancer prevention and (b) the relation between nutrition and cancer mortality could be even stronger if applied to the whole population, since a 1-g increase in vegetable protein consumption would result in a reduction of 2.5 cases out of 100, a 1-g increase in fibre would result in a reduction of four cases out of 100 and a 1-g increase in animal fat would result in an increase of one case out of 100.