Persistent organic pollutants in breast milk of mothers residing around an open dumping site in Kolkata,India: Specific dioxin-like PCB levels and fish as a potential source

Concentrations of persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and organochlorine pesticides were measured in human breast milk collected from mothers residing near an open dumping site and a reference site in Kolkata, India during 2004–2005. POPs were detected in all the human milk samples analyzed, suggesting that residents of Kolkata are widely exposed to these contaminants. Concentrations of dioxin-like PCBs in the samples from the dumping site were significantly higher than in the reference site samples, whereas no such difference was found for PCDDs and PCDFs. In addition, significantly higher concentrations of total PCBs were also observed in the samples from the dumping site than the reference site. Interestingly, concentrations of total and dioxin-like PCBs in the breast milk of mothers from the dumping site significantly increased with the number of years of residence near the dumping site. These results indicate that significant pollution sources of PCBs are present in the dumping site of Kolkata and the residents living around are exposed to relatively higher levels of PCBs. When the residue levels of dioxins and related compounds in fish collected from ponds near the Kolkata dumping site and the reference site were measured, it was found that dioxin-like PCB and TEQ levels in fish from the dumping site were notably higher than those from the reference site. This result indicates that fish is a potential source of PCBs for residents living near the Kolkata dumping site.     

Photolysis of oxyfluorfen in aqueous methanol

Photolysis of oxyfluorfen, an herbicide of the nitrodiphenyl ether class, was studied in aqueous methanol under UV and sunlight. UV irradiation was carried out in a borosilicate glass photoreactor (containing 250 ppm oxyfluorfen in 50% aqueous methanol) equipped with a quartz filter and 125 watt mercury lamp (maximum output 254 nm) at 25 ± 1°C. Sunlight irradiation was conducted at 28 ± 1°C in borosilicate Erlenmeyer flasks containing 250 ppm oxyfluorfen in 50% aqueous methanol. The samples from both the irradiated conditions were withdrawn at a definite time interval and extracted to measure oxyfluorfen content by gas chromatography-flame ionization detector for rate study. The half-life values were 20 hours and 2.7 days under UV and sunlight exposure, respectively. Photolysis of oxyfluorfen yielded 13 photoproducts of which three were characterized by infrared spectrophotometer and ¹H NMR and ¹³C NMR spectroscopy. The rest of the photoproducts were identified by gas chromatography-mass spectrometry (GC-MS) and thin layer chromatography (TLC). An ionization potential 70 eV was used for electron impact-mass spectrometry (EI-MS) and methane was used as reagent gas for chemical ionization-mass spectrometry (CI-MS). Two of the photoproducts were also synthesized for comparison. The main phototransformation pathways of oxyfluorfen involved nitro reduction, dechlorination, and hydrolysis as well as nucleophiles displacement reaction.     

Physiological and chemical response of the lichen, Flavoparmelia caperata (L.) Hale, to the urban environment of Kolkata, India

The present study was focused on the effect of increasing urbanization including industrial and traffic activity on the accumulation of heavy metals and possible damage of selected physiological parameters (composition of assimilation pigments, membrane lipid peroxidation, and membrane integrity) of an epiphytic foliose lichen, Flavoparmelia caperata (L.) Hale. The lichen samples were collected from three different localities in and around Kolkata, India, two sites being from the urban area and one from the relatively non-polluted sub-urban area. The results showed that thalli from the urban sites have significantly higher concentrations of Fe, Cr, Cu, Zn, and Pb compared to those collected from the sub-urban site. Physiological parameters of damage also exhibited stress symptoms in thalli from the urban sites—decreased chlorophyll a indicating less photosynthetic efficiency, and increase in lipid peroxidation and electrolyte conductivity indicating cell membrane injuries. Correlation studies among metals pinpointed vehicular traffic as the main source of pollution in this area.     

Assessment of the impact of pesticide residues on microbiological and biochemical parameters of tea garden soils in India

The main aim of this study was to assess the impact of pesticidal residues on soil microbial and biochemical parameters of the tea garden soils. The microbial biomass carbon (MBC), basal (BSR) and substrate induced respirations (SIR), β -glucosidase activity and fluorescein diacetate hydrolyzing activity (FDHA) of six tea garden soils, along with two adjacent forest soils (control) in West Bengal, India were measured. The biomass and its activities and biochemical parameters were generally lower in the tea garden soils than the control soils. The MBC of the soils ranged from 295.5 to 767.5 μ g g^{? 1}. The BSR and SIR ranged from 1.65 to 3.08 μ g CO₂-C g^{? 1} soil h^{? 1} and 3.08 to 10.76 μ g CO₂-C g^{? 1}h^{? 1} respectively. The β -glucosidase and FDHA of the soils varied from 33.3 and 76.3 μ g para-nitrophenol g^{? 1} soil h^{? 1} and 60.5 to 173.5 μ g fluorescein g^{? 1}h^{? 1}respectively. The tea garden soils contained variable residues of organophosphorus and organochlorine pesticides, which negatively affected the MBC, BSR, SIR, FDHA and β -glucosidase activity. Ethion and chlorpyriphos pesticide residues in all the tea garden soils varied from 5.00 to 527.8 ppb and 17.6 to 478.1 ppb respectively. The α endosulfan, β endosulfan and endosulfan sulfate pesticide residues in the tea garden soils ranged from 7.40 to 81.40 ppb, 8.50 to 256.1 ppb and 55 to 95.9 ppb respectively. Canonical correlation analysis shows that 93% of the total variation was associated with the negative impact of chlorpyriphos, β and α endosulfan and endosulfan sulfate on MBC, BSR and FDHA. At the same time ethion had negative impact on SIR and β -glucosidase. Data demonstrated that the pesticide residues had a strong impact on the microbial and biochemical components of soil quality.     

Effects of unregulated anthropogenic activities on mixing ratios of volatile organic air pollutants—A case study

During the months of October to November, many important festivals are celebrated in India. Celebration of these festivals are marked by extensive use of fireworks or pyrotechnics, bonfire, incense burning, open air community cooking, and temporary eateries using crude fuel such as coal, wood, kerosene, cow dung, burning of raw/semiwood, and coconut shells. The present study deals with the influence of these unregulated anthropogenic activities on ambient mixing level of volatile organic compounds (VOCs), especially some carbonyl compounds. The study was undertaken in the metropolitan city of Kolkata, India, with very high population density, which is even higher during festival period. The average total carbonyl level at different sites in Kolkata varied from 134.8 to 516.5 μg m^?3 in pre-festival season, whereas in post-festival season the same varied from 252.2 to 589.3 μg m^?3. Formaldehyde to acetaldehyde ratio altered from 0.62 in pre-festival season to 1.78 in post-festival season. Diurnal variation also altered, indicating variation in source composition of carbonyls. The total ozone forming potential calculated for all 14 carbonyls in pre-festival season increased by 35% in post-festival season. The effect of anthropogenic activities typical to the event of Diwali night characterized by intense execution of pyrotechnics resulted in significantly high level of carbonyl VOCs. Principal component analysis study for the event of Diwali shows clear contribution of the event on certain carbonyl VOCs. The results indicate elevated primary emissions of these pollutants and also their effect on formation of secondary pollutants. The study emphasizes the need of generating awareness among the communities in society as well as need for regulations to minimize the emissions and related hazards to the extent possible.

Implications: Altered anthropogenic activities typical of festival season including extensive use of pyrotechnics affect ambient level of volatile organic compounds, especially some carbonyls. Such activities have considerable effect on interspecies ratio and diurnal variation. They also affect formation of secondary pollutants such as tropospheric ozone. Principal component analysis (PCA) study shows clear contribution of the pyrotechnics execution on certain carbonyl VOCs. The findings emphasize the need of generating awareness in society and need for regulations to minimize the emissions.     

L-asparaginase and L-glutaminase activities in submerged rice soil amended with municipal solid waste compost and decomposed cow manure

The field study was conducted to evaluate the effect of municipal solid waste compost (MSWC) as a soil amendment on L-asparaginase (LA) and L-glutaminase (LG) activities. Experiments were conducted during the wet seasons of 1997, 1998 and 1999 on rice grown under a submerged condition, at the Agriculture Experimental Farm, Calcutta University at Baruipur, West Bengal, India. The treatments consisted of control, no input; MSWC, at 60 Kg N ha(- 1); well-decomposed cow manure (DCM), at 60 Kg N ha(- 1); MSWC (30 Kg N ha(- 1)) + Urea (U) (30 Kg N ha(- 1)); DCM (30 Kg N ha(- 1)) + U (30 Kg N ha(- 1)) and Fertilizer, (at 60:30:30 NPK kg ha(- 1)) through urea, single superphosphate and muriate of potash respectively). LA and LG activities alone and their ratio with organic-C (ratio index value, RIV), straw and grain yield were higher in DCM than MSWC-treated soils, due to higher amount of biogenic organic materials like water-soluble organic carbon, carbohydrate and mineralizable nitrogen in the former. The studied parameters were higher when urea was integrated with DCM or MSWC, compared to their single applications. The heavy metals in MSWC did not detrimentally influence the above-measured activities of soil. In the event of long term MSWC application, changes in soil quality parameters should be monitored regularly, since heavy metals once entering into soil persist over a long period.     

Assessment of thermal stress adaptation by monitoring Hsp70 and MnSOD in the freshwater gastropod,Bellamya bengalensis (Lamark 1882)

Expression of the stress biomarkers 70-kDa heat shock proteins (Hsp70) and manganese superoxide dismutase (MnSOD) was measured as the molecular basis of adaptive response against increased experimental temperatures (32–40 °C for a span of 24–72 h) on the fresh water molluscan species, Bellamya bengalensis (Lamark 1882). The experimental snail specimens were collected during summer and winter seasons from two contrasting wetlands: an ecorestored (free from human interference) site (SI) and other experiencing anthropogenic stresses (SII). The mortality rate of the B. bengalensis and the immunoblotting of MnSOD and Hsp70 of their digestive glands were performed at regular intervals during the period of heat stress. The SI provided a lower stress environment based on physicochemical parameters such as pH, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), and alkalinity for the survival of test species, although both sites experienced mortality due to thermal stresses. The parity in protein expressions displayed a uniform mode of adaptive impact to temperature elevations in both field and laboratory exposure. The Hsp70 expression was minimal at lower thermal stress, but increased with a rise in temperature. It is very likely that higher Hsp70 levels are not directly related to survival or adaptation. In contrast, MnSOD levels appeared to be an indicator of adaptive responses vis-a-vis survival of the animals. So, the expression levels of a universal free radical scavenger like MnSOD are recognized as a potential biomarker in a bioindicator species like Bellamya.     

L-asparaginase and L-glutaminase activities in submerged rice soil amended with municipal solid waste compost and decomposed cow manure

The field study was conducted to evaluate the effect of municipal solid waste compost (MSWC) as a soil amendment on L-asparaginase (LA) and L-glutaminase (LG) activities. Experiments were conducted during the wet seasons of 1997, 1998 and 1999 on rice grown under a submerged condition, at the Agriculture Experimental Farm, Calcutta University at Baruipur, West Bengal, India. The treatments consisted of control, no input; MSWC, at 60 Kg N ha^{? 1}; well-decomposed cow manure (DCM), at 60 Kg N ha^{? 1}; MSWC (30 Kg N ha^{? 1}) + Urea (U) (30 Kg N ha^{? 1}); DCM (30 Kg N ha^{? 1}) + U (30 Kg N ha^{? 1}) and Fertilizer, (at 60:30:30 NPK kg ha^{? 1}) through urea, single superphosphate and muriate of potash respectively). LA and LG activities alone and their ratio with organic-C (ratio index value, RIV), straw and grain yield were higher in DCM than MSWC-treated soils, due to higher amount of biogenic organic materials like water-soluble organic carbon, carbohydrate and mineralizable nitrogen in the former. The studied parameters were higher when urea was integrated with DCM or MSWC, compared to their single applications. The heavy metals in MSWC did not detrimentally influence the above-measured activities of soil. In the event of long term MSWC application, changes in soil quality parameters should be monitored regularly, since heavy metals once entering into soil persist over a long period.