RESUMO
Groundwater quality analyses included pH, EC, cations (Ca2+, Mg2+, Na+, K+, Zn2+, Cu2+, Mn2+, Fe3+ and As3+), anions (CO32-, HCO3-, NO3-, SO42-, PO43- and Cl-) and TDS of northwestern Bangladesh. The samples contained Ca2+, Mg2+ and Na+ as the dominant cations and HCO3- and Cl- were the dominant anions. Ratios of major cations and anions of water samples suggest the predominance of Ca and Mg-containing minerals over Na-containing minerals. According to TDS and SAR values, all samples were classed as 'freshwater' and 'excellent' categories. The SSP of all waters was under 'excellent' and 'good' classes. All samples were within 'soft' class regarding hardness with 'suitable' RSC. Based on As3+, Zn2+, Mn2+, Fe3+, SO42-, NO3- and Cl- all groundwater samples were within the 'safe' limit for drinking but unsuitable for some industries for specific ions.
As análises de qualidade de Lençol de Água incluíram pH, EC, e os cations,(Ca2+, Mg2+, Na+, K+, Zn2+, Cu2+, Mn2+, Fe3+ e As3+), aníons ( CO32-, HCO3-, NO3-, SO42-, PO43- e Cl-e TDS do noroeste do Bangladesh. As amostras continham Ca2+, Mg2+ e Na+ e como o cations dominante HCO3- e Cl foram os aníons dominantes. Segundo o TDS e valores de SAR, todas as amostras foram classificadas como categorias 'de água doce' e 'excelentes'. O SSP de todas as águas foi nas classes 'excelentes' e 'boas'. Todas as amostras foram dentro da classe 'suave' quanto à dureza com RSC 'conveniente'. Baseado As3+, Zn2+, Mn2+, Fe3+, SO42-, NO3- e Cl- - todas as amostras de lençol de água foram dentro do limite 'seguro' como água de bebida mas impróprias para algumas indústrias que emprega íons específicos.
RESUMO
How might we overcome the lack of archival resources while doing the history of science in India? Offering reflections on the nature of archival resources that could be collected for scientific institutions and the need for new interpretative tools with which to understand these resources, this essay argues for the use of oral history in order to understand the practices of science in the postcolonial context. The oral history of science can become a tool with which to understand the hidden interactions between the world of scientific institutions and the larger world of the postcolonial nation.
