Environmental cancer in the Indian context--an overview.

Problems related to environmental carcinogenesis have begun to surface with increased industrial activity and diffusion of hazardous chemicals. Cancer Registries maintained in some of our cities can help in retrospectively analysing incidence and related aetiology. Even a casual analysis of the existing data related aetiology. Even a casual analysis of the existing data belies the oversimplicity of the WHO model used in developing countries to asign lower priority to cancer prevention and control than to communicable diseases. Exposure data to environmental inducers of cancer, radiations, chemicals and other stresses is urgently needed. Prevention strategy should be more and more on a scientific base for an early detection and risk estimates of chemical exposures. Sustained environmental monitoring for inducers and cofactors are required. The Factory Act must make provision for appropriate health surveillance of workers over a long period.

Biological effects of chemical disasters : Human victims

A conceptual model is persented for a systems approach to the study of the biological effects of massive chemical exposures. The effects on the pulmonary system and on the skin are of immediate concern in accidents where toxic gases are released into ambient air of the neighbourhood. Detoxification function will have to be assessed and manipulated for successful antidotal therapy mutagenic effects including cancer and behavioural disturbances have to be ploying epidemiological techniques.(AU)

Metabolic activity of lysosomes in tin-intoxicated regenerating rat liver.

The metabolic activity of lysosomes was monitored by assaying the lysosomal enzymes. DNase, RNase, acid phosphatase and cathepsin in rat liver regenerating after partial hepatectomy at various intervals after the operation. Results of the present study demonstrate that the activities of lysosomal enzymes are increased significantly during the process of rapid regeneration, especially at 24 h and 48 h. A small rise in enzymatic activities was noticed at 36 and 72 h of regeneration, leading towards normalisation at 168 h. Administration of tin(II) tartrate (25 mu mol Sn2+/100 gm body wt.) significantly increased the DNAse and RNAse activity at 24 h of the regeneration, while a decrease was noticed in acid phosphatase activity. An increase was also found in the catheptic activity of tin-treated hepatectomized rats. It can thus be concluded that an increased metabolic activity of lysosomes is reflected by the increased activity of its hydrolytic enzymes during the regeneration, and tin at low concentrations is helpful to this process. Further work is in progress to gain insight into the other metabolic activity of the lysosomes during the process of regeneration.

The water flea (Daphnia magna) as a sensitive indicator for the assessment of toxicity of synthetic detergents.

The water flea (Daphnia magna) was used as a sensitive indicator for assessing the toxicity due to synthetic detergents. Acute and chronic toxicity of detergents to the water flea was studied under laboratory conditions by following the median tolerance limit (TLM) at 48 hr and the rate of survival. A significant decrease in the rate of reproduction (number of hatching and neonates produced) were found at 21 days. During acute toxicity studies behavioural changes were also noticed.

Effect of mica dust and choline on the lymph nodes of rats.

Male albino rats given choline alone by intraperitoneal injection (40 doses of 25 mg/5 days a week over a period of 10 weeks), developed atypical lymphadenopathy at the end of the experiment (330 days). In a second group, the intratracheal instillation of single dose of 25 mg of respirable mica provoked proliferation of reticular cells and macrophages in the tracheobronchial lymph nodes. However, in a third group, the combined action of choline and mica caused marked lymphadenopathy with abnormal cells. The role of choline, an essential component of cell membrane, in enhancing the reaction to mica in the lymph nodes, is discussed.

45Ca uptake from water by snails (Lymnaea vulgaris) in control and detergent-polluted samples.

A biostatic assay method involving 45Ca uptake into shells and tissues of snails (Lymnaea vulgaris) in 72 hr was developed to follow the effect of detergent-polluted water on ecosystems. There was a marked decrease in the 45Ca uptake by shells and tissues of linear alkyl benzene sulfonate-exposed animals as compared to controls. No change in 45Ca uptake was observed in dead shells, thereby excluding the possibility of passive exchange.

Comparative studies on ecotoxicology of synthetic detergents.

To predict the comparative toxicological response of synthetic detergents on aquatic ecosystems, the effects of various concentrations of neutralized alkyl benzene sulfonate were studied. The median tolerance limit at 48 hr, 95% confidence limit, slope function, presumable harmless concentration, and rate of survival of different species of aquatic fauna such as water fleas (Daphnia magna), mosquito larvae (Culex pipiens), slug worms (Tubifex rivulorum), snails (Lymnaea vulgaris), tadpoles (Rana cyanophlyctis), and fish fingerlings (Cirrhina mrigala) were followed at 0, 24, 48, 72, and 96 hr. Any effect on quality of the water was also tested after the addition of various concentrations of detergents. The results showed that water fleas are more susceptible to detergent toxicity than fish fingerlings, tadpoles, slug worms, snails, and mosquito larvae. Behavioral changes were also observed as an index for detergent toxicity. The relative toxicity of the detergents to various species is discussed in relation to selective ecotoxicological response.