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Organochlorine pesticide residues in sediment and fish samples collected from the east and west coasts of India are presented. HCH isomers and DDT and its metabolites are the predominantly identified compounds in most of the samples. Despite the higher quantity of consumption, HCH and DDT levels in fish in India were lower than those in temperate countries suggesting a lower accumulation in tropical fish, which could be due to rapid volatilization and degradation of these insecticides in the tropical environment. The predominance of alpha- and beta-HCH reflect the use of technical grade HCH in India. The high temperature in the tropics also enhances the elimination rate of chemicals in fish, as the biological half-lives of semivolatile compounds such as DDT are short at high temperature.

The daily intake of manganese (Mn) estimated through air, water and duplicate dietary analysis is found to range from 0.67 to 4.99 mg with a mean value of 2.21 mg. Ingestion through food contributed to the predominant fraction of the intake. The turnover rate of Mn through blood is approximately 2 h, based on the mean concentration of Mn in blood of 1.54 microg l(-1). The average concentrations of Mn in water and air were approximately 1.42 microg l(-1) and 37 ng m(-3), respectively. The daily intake of Mn by the adult population of Mumbai is closer to the lower bound of the recommended limit of 2-5 mg. Electro Thermal Atomic Absorption Spectrophotometry (ET-AAS), has been used for the determination of Mn in a variety of environmental and human biological fluids. The detection limit of Mn for a volume injection of 20 microl is 2 pg absolute. The precision of the method is established by analyzing a synthetic mixture containing various elements in different quantities (0.5-10 ppm) and is found to be within +/- 8%. The reliability of estimation is further assessed through the analysis of Standard Reference Materials (SRMs) of soil, hay, milk powder and fish tissue obtained from IAEA.

Heavy metal concentrations have been determined in maternal and cord blood samples collected from mothers in the age group 20-25 years with full-term neonates (37-40 weeks). The concentrations of Pb, Cd, Cu and Zn were found to be low in cord blood as compared to mother's blood and the ratio between cord blood and maternal blood for the respective elements was found to be approximately 0.80, 0.86, 0.47 and 0.40. On the other hand, the concentrations of Fe and Mg in the mother's blood were found to be lower than those in the cord blood. Prenatal exposure to lead in Mumbai, though low (5.1 microg/dl), is approximately 2-3 times higher than that observed in Canada or Italy. A strong correlation (r = 0.79) between the maternal and cord blood lead levels has been observed during the present study.

The study area Thane Creek, lies on the southern part of the Deccan belt of India between latitude 18 degrees 53'-19 degrees 04' N and longitude 72 degrees 48'-72 degrees 53' E and includes the Ulhas river estuaries. Lead-210 (half-life of 22.3 years) is used for an estimation of recent sedimentation rate in Thane Creek using radiochemical separation and alpha counting of its grand-daughter 210Po. The concentration of Hg and Ni in vertical depth profiles of sediment is estimated to assess the anthropogenic input of these nuclides due to large-scale industrialization which has taken place at this site during last two decades. Depth-wise concentration profiles of Hg and Ni indicate positive evidence of continued fresh inputs into the Airoli section of Thane Creek.

Concentrations of the essential elements Zn and Cu and potentially toxic elements Pb and Cd in different milk samples and baby food materials were measured, primarily to assess whether the intakes comply with recommended desired levels for essential and permissible levels for toxic elements. The geometric mean concentrations of Pb, Cd, Cu and Zn in different types of milk were found to vary from 1.70 to 3.35, 0.07 to 0.10, 43.2 to 195 and 1772 to 4230 micrograms/l, while the same in different baby foods had values from 39.5 to 77.7, 0.45 to 17.7, 1106.3 to 3157.3 and 9367 to 34,592 micrograms/kg, respectively. The concentration of Cd was found to be very low (0.1 microgram/l) and fairly constant in all types of milk. The lead content in cow milk was observed to be lowest even in comparison with breast milk. Concentrations of all these metals are approximately one order of magnitude higher in baby food products than those observed in different types of milk owing to higher fat content. The infant baby food Amul Spray contains low concentrations of toxic (Pb and Cd) and high concentrations of essential (Cu and Zn) elements. The daily intakes of Pb, Cd, Cu and Zn by infants through milk and baby foods marketed in Mumbai city have also been estimated. The daily intakes of Pb (1.1 micrograms/kg) and Cd (0.01 microgram/kg) for infants through baby foods are well below the recommended tolerable levels of 3.57 micrograms/kg and 0.8-1.0 microgram/kg, respectively. Similarly the daily intake levels of essential elements are also significantly lower than the recommended desirable levels of 3-5 mg and 0.5-1.0 mg for Zn and Cu, respectively. Milk from an Indian mother also does not provide adequate levels of essential elements to the infants and children.

Concentrations of heavy metals such as Pb, Cd, Cu and Zn have been estimated in air particulates, water and food samples collected from different suburbs in Bombay during 1991-1994. The concentrations of these metals are translated into intake rates through inhalation and ingestion pathways. Results indicate the highest concentration of Pb and Cu are in pulses (green gram), Cd in leafy vegetables (amaranth) and Zn in meat. Root vegetables and fruits contained a lower concentration of these metals. Total intakes of Zn, Cu, Pb and Cd through air, water and food were 10,500 micrograms/day, 1500 micrograms/day, 30 micrograms/day and 4.3 micrograms/day, respectively. Although the major contribution for the daily intake is the ingestion route, eventual uptake in the body stream is contributed through inhalation for Pb (41%) and Cd (16%) and ingestion for Cu (98.8%) and Zn (99.6%). The total intake of these elements through the duplicate diet study is 9500 micrograms/day for Zn, 1770 micrograms/day for Cu, 27 micrograms/day for Pb and 2.5 micrograms/day for Cd, respectively. The daily intake of these metals by the population of Bombay is well below the recommended dietary values.

Hydride generator atomic absorption spectrophotometry (HG-AAS) is employed for the determination of arsenic in air, duplicate diet and body fluids. The detection limit for arsenic is 0.02 ppb. The reliability of the analysis is assessed through analysis of Standard Reference Materials (SRMs) of soil and fish tissue obtained from IAEA. The concentration of arsenic in atmospheric air particulates collected from different suburbs showed geometric means in the range of 1.9-5.6 ng/m3. The total intake of arsenic through air and duplicate diet is approximately 10 micrograms/day for the adult population of Bombay (Mumbai) City. The dietary intake through food is the major contributor to the total intake. The turnover time of arsenic in blood is estimated to be approximately 33 days based on the observed mean concentration of arsenic in blood of 1 microgram/dl. The daily intake of arsenic by the adult population of Bombay is much lower than the WHO recommended value of 140 micrograms.

Reversed phase high performance liquid chromatography (HPLC) with ultra violet detection (UV) was optimised for separation and quantification of methyl mercury in coastal sediment and fish samples. The extraction efficiency of methyl mercury from sediment and biological samples was found to be 56% with a detection limit of 0.5 ng for a 200 microliters sample volume. The concentrations of methyl mercury and the relative fractions with respect to total mercury were distinctly lower, 5.9-65.5 ng/g (3-8%) in sediment compared to biological samples, 20.4-344.5 ng/g dry wt. (33-97%). The daily intake of methyl mercury by the Mumbai population through marine food is about 0.5 microgram forming 62% of the total mercury intake from this route.