Ramesh C. Sharma

Contamination levels and spatial distribution of organochlorine pesticides in soils from India.

Organochlorine pesticides, dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH), are potential chemical pollutants extensively used for agriculture and vector control purposes due to low cost and high effectiveness. Concentrations of HCH and DDT were determined in 175 surface soil samples from different agricultural fields, fallow and urban lands of districts Nagaon and Dibrugarh, Assam, India. The mean concentrations of total HCH and total DDT were 825 ng/g (range: 98-1945 ng/g) and 903 ng/g (range: 166-2288 ng/g) in district Nagaon while 705 ng/g (range: 178-1701 ng/g) and 757 ng/g (range: 75-2296 ng/g) in district Dibrugarh, respectively. The soils from paddy fields contained highest amounts of HCH and DDT residues. Total organic carbon was found to be positively associated with soil HCH and DDT residues. Ratios of DDT/(DDD+DDE) were 1.25 and 1.82 while of α/γ HCH were 2.78 and 2.51 for districts Dibrugarh and Nagaon, respectively. Source identification revealed that soil residue levels have originated from long past and recent mixed source of technical HCH and Lindane for HCHs and mainly technical DDT for DDTs. Spatial distribution was also investigated to identify the areas with higher pesticide loadings in soil.

Assessment of organochlorine pesticides in human milk and risk exposure to infants from North-East India.

Despite the worldwide ban on use of persistent organochlorine pesticides, their usage continued until recently in India, for vector-borne disease eradication programs and agricultural purposes. The concentrations of organochlorine contaminants, DDT and HCH, have been determined in human breast milk from Dibrugarh and Nagaon districts of Assam state, North-East India. The results demonstrated that the mean levels of total DDT were 3210 ng/g lipid wt. and 2870 ng/g lipid wt. and total HCH were 2720 ng/g lipid wt. and 2330 ng/g lipid wt. in Nagaon and Dibrugarh respectively. There was no significant difference in the levels of investigated pollutants between the two districts. Significant differences in ADI (Average daily intake) for total DDT were found between the two districts. In addition, a positive correlation was observed between OCP levels in breast milk and age of mothers. Based on OCP levels in human breast milk, the ADI by the infants has been estimated. It has been found that high daily intake of DDTs and HCHs by the infants exceeded the TDI (Tolerable daily intake) which implied that infants of the region are potentially at high risk by these contaminants.

ANTICIPATED AIR POLLUTION TOLERANCE OF SOME PLANT SPECIES CONSIDERED FOR GREEN BELT DEVELOPMENT IN AND AROUND AN INDUSTRIAL/URBAN AREA IN INDIA: AN OVERVIEW

Vegetation naturally cleanses the atmosphere by absorbing gases and some particulate matter through leaves. Plants have a very large surface area and their leaves function as an efficient pollutant‐trapping device. Some plants have been classified according to their degree of sensitivity and tolerance towards various air pollutants. Sensitive plant species are suggested to act as bio‐indicators. Levels of air pollution tolerance vary from species to species, depending on the capacity of plants to withstand the effect of pollutants without showing any external damage. In this study, the air pollution tolerance index (APTI) of 30 plant species has been evaluated. High values of APTI were recorded in Mangifera indica, Moringa pterydosperma, Cassia renigera and Ailanthus excelsa. The anticipated performance index (API) of 30 plant species has also been evaluated for green belt (GB) development in and around an industrial urban area in India. Using APTI and this performance rating, the most tolerant plants have been identified.

Organochlorine pollutants in human blood and their relation with age, gender and habitat from North-east India

Organochlorine pesticides (OCPs) have been beneficial to man and environment but their inadvertent use has caused considerable harm to human health. Despite the proliferation of different types of pesticides, organochlorines such as HCH and DDT still account for two third of the total consumption in India because of their low cost and versatility in action again various pests. Since, Assam, a state in North-eastern part of India is an endemic area with perennial transmission where mosquito borne diseases are serious health problems; these pesticides are still being used in huge quantities in vector control as well as in agriculture. A total of 331 human blood samples were collected from district Nagaon and Dibrugarh of Assam to determine the residue levels of DDT and HCH in human blood. The concentrations of selected persistent organochlorine pollutants were measured with gas chromatography-electron capture detector. The results demonstrated that the mean levels of total DDT and HCH were 743 μg L(-1) and 627 μg L(-1) for district Nagaon while 417 μg L(-1) and 348 μg L(-1) for district Dibrugarh. The difference of total HCH and total DDT between these two districts was found to be highly significant (P<0.0001). Among DDT metabolites, the same trend was observed for both the districts as p,p-DDT was the principal component contributed 41% for Nagaon and 58% for Dibrugarh. In case of HCH residues, for Nagaon, β-HCH was the predominant contaminant comprised more than 34% while for Dibrugarh, it was α-HCH that was contributing 43% of total HCH concentration.

Biodiversity, ecological status and conservation priority of the fish of the River Alaknanda, a parent stream of the River Ganges (India)

1. The River Alaknanda is a tributary of the River Ganges, originating from the Garhwal Himalaya in India and sustaining about 39 fish species from 15 genera and five families. 2. A diversity index has been calculated for the fish communities ranging from 0.407 to 0.593; no significant difference in diversity was noted at the three sampling sites which is attributed to the homogeneity of the ecological conditions. A similarity index was found to be high between the sampling sites and ranged from 93.47 to 100. 3. The categories of threats to the fish and priority for species conservation have been determined. Fourteen species were assigned as Abundant, seven species as Vulnerable, 15 species at Lower Risk, one species as Data Deficient while two species were assigned as Endangered. 4. The conservation of fish has been given little attention in India. The options for the conservation of the fish dwelling in the Alaknanda include ex situ and in situ conservation, habitat restoration, translocation and captive breeding. 5. The creation of fish sanctuaries and public awareness of the importance of fish species and their conservation will be critical for the proper conservation and management of the Garhwal Himalayan fish. Significantly, there are some parts of the river where fish are preserved out of religious sentiments. Careful nurturing of such sentiments may prove to be highly beneficial.

Air pollution control by optimal green belt development around the Victoria Memorial Monument, Kolkata (India)

Mitigation of air pollution in developing countries like India has emerged as one of the challenging tasks for environmental management agencies. The status is likely to become more acute with the continued and enhanced rate of industrial expansion and the limitations of carrying capacity of the respective environmental basins. India being a developing country, end-of-pipe treatment/tail gas treatment alone is not techno-economically feasible in certain important industrial sectors. Fugitive/line sources and control emission at source is not feasible because of exorbitant costs. In the country as a whole, green belt development around the industrial/urban settlement will act as a cost effective solution for air pollution abatement. Green belt designing in an appropriate scientific manner not only reduces air pollution, but also attenuates noise pollution. This paper looks at the designing of an optimal green belt around the Victoria Memorial Monument based on ambient air quality, soil characterization, climatic condition and existing plant communities. The effectiveness of the green belt around the Victoria Memorial Monument has been assessed; and analyses of different parameters, viz. tree height ( h ), width of green belt ( X 2 ), distance of green belt from the source ( X 1 ) are shown.

Contamination of aquatic system by chlorinated pesticides and their spatial distribution over North-East India

Organochlorine pesticides, the potential chemical pollutants, are extensively used for agriculture and vector control purposes due to their low cost and high effectiveness. DDT and HCH residues were examined in different surface and groundwater resources of district Dibrugarh and Nagaon of Assam state, Northeast India. The mean HCH concentrations in surface water samples were 4403 ng/L and 4911 ng/L, while 5168 ng/L and 5574 ng/L in groundwater samples from Dibrugarh and Nagaon districts respectively. Total DDT levels were 5402 ng/L and 6121 ng/L in surface water while 6549 ng/L and 6904 ng/L in groundwater from Dibrugarh and Nagaon respectively. DDT levels in groundwater were found to be highest among the levels reported so far. The dominant OCPs were found to be β-HCH among HCHs and p,p′-DDT among DDTs. The ratios of DDT/(DDE+DDD) and α-HCH/γ-HCH revealed that residue levels in water were originated from long past to recent mixed source of technical HCH and lindane for HCHs and mainly technical DDT for DDTs. About 93% samples for DDT and 90% samples for HCH exceeded the WHO recommended drinking water limits which is a matter of great concern and posing a serious threat to aquatic ecosystem and human health. Spatial distribution was also investigated to identify the areas with higher pesticide loadings in groundwater. Present data on contamination profile of OCPs in this survey can be used as reference levels for future POPs monitoring programme.

Age and growth of a Himalayan teleost Schizothorax richardsonii (Gray) from the Garhwal Hills (India)

Abstract Scales from 313 specimens of a Himalayan teleost Schizothorax richardsonii from the Alaknanda hillstream in the Garhwal Himalayas were read for age determination and calculation of growth parameters. There was a strong linear relationship between fish length and lateral scale radius. Annuli formation occurred in August–September coinciding with spawning and the frequent flash floods in Garhwal. The growth constant parameter indicated that the fish enter ‘old age’ in the fifth year of life. Growth rate decreases successively at higher ages.

Traditional resource management practices for biodiversity conservation and their significance in Nanda Devi Biosphere Reserve, India

The Nanda Devi Biosphere Reserve is considered one of the most biologically diverse and socio-culturally rich biosphere reserves in India. From ancient times, the local community considered the entire biosphere area as a sacred landscape, and institutionalized a number of resource conservation and utilization practices through their customs/traditions and religious beliefs. Traditional Resource Management Practices (TRMPs) have evolved through co-existence, interactions, and a reciprocal responses between society and nature. These can be classified into four broad categories: (a) provision of a return to nature; (b) restraints on over-utilization or wastage of resources; (c) management of resources according to their use for subsistence; and (d) creation of opportunities for natural regeneration. In the last hundred years, the age-old TRMPs have been replaced by scientific management systems, which have led to alienation of the community from management of their resources. Conservation of the natural system while ignoring the social system has created severe imbalances in the overall ecosystem of the area. True participation of the local community in the scientific resource management can only be achieved by providing due credit to TRMPs. Therefore, planning of biodiversity conservation should be based on a healthy interaction between formal ecological science and traditional knowledge.