Pollution

Electronic industry is one of the fastest growing manufacturing industry in India. But the increase in sales of electronic goods and their rapid obsolescence has resulted in generation of electronic waste, which is popularly known as E-waste. It includes discarded electronic and electrical equipment. Developing countries face enormous challenges which are related to the generation and management of E-waste which are either internally generated or imported illegally; India is no exception. However, the existing management practices related to E-waste in India are reasonably poor and have the potential to risk both human health and the environment. Moreover, the policy level initiatives are not being implemented appropriately. This paper reviews E-waste generation, present scenario in India, health and environmental implication of E-waste and E-waste management in India.

Heavy metals contamination was carried out with the aim to assess the levels of lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn) and chromium (Cr) in various fruits and vegetables sold in Ghanaian markets. A total of 350 fruits and vegetable samples were tested and analyzed by Atomic Absorption spectrometry. The test results showed that the average concentrations detected were ranged from below detection limit to 0.56, below detection limit to 0.08, 1.24 to 6.32, 2.32 to 21.4 and below detection limit to 1.06 mg/kg for Pb, Cd, Cu, Zn and Cr, respectively. The highest mean levels of Pb and Cd were detected in lettuce, Cu and Zn in cucumber and Cr in carrot samples. The daily intakes of Pb, Cd, Cu, Zn and Cr through fruits and vegetables have also been estimated. The levels of metals were all below the permissible limits by WHO/FAO. For there were heavy metals present in the fruits and vegetable samples, consumption of fruits and vegetables there was no zero risk. But the exposure of consumer did not exceed the acceptable daily intake (ADI). This study suggests that a yearly monitoring program for heavy metal in foodstuffs is necessity.

In this study, the Azadirachta Indica tree was evaluated as the biomonitors of heavy metals such as Fe, Mn, Zn and Cu contaminated in Madurai City. The soil samples at depth ( 0-20cm) and Azadirachta Indica leaves were taken from different sampling sites namely Kalavasal (S1), Palaganatham (S2), Periyar (S3), Simmakal (S4), Goripalayam (S5) and Mattuthavani (S6). Then, the concentrations of Fe, Mn, Zn and Cu were measured using Flame Atomic Absorption Spectrophotometer Perkin Elmer Model 1100. The result of this study showed that the concentration of Fe, Mn, Zn and Cu varied between 11.96µg/m3-21.6 µg/m3, 5.36 µg/m3 - 16.25 µg/m3, 4.38 µg/m3 - 7.22 µg/m3 and 1.58 µg/m3 - 5.03 µg/m3respectively at depth 0-20cm. The concentration of heavy metals such as Fe, Mn, Zn and Cu in Azadirachta Indica ranged between 206.92 µg/m3- 1661.3 µg/m3, 45.0 µg/m3 – 273.75 µg/m3, 112.67 µg/m3 – 345.67 µg/m3 and 15.0 µg/m3 - 23.25 µg/m3 respectively. According to these results the concentration of heavy metal Fe was found to be high in all the sampling sites at depth of soil 0-20cm. The mobility ratio value for heavy metals in Azadirachta Indica was found to be greater than one in all the sampling sites, thus Azadirachta Indica is said to be heavy metal accumulator. The variation in heavy metal concentrations is due to changes in traffic density and anthropogenic activities. It is concluded that Azadirachta Indica can be applied to monitor polluted sites.

Comparative study of the adsorption capacities of four calcareous shells for Pb(II), Cr(VI) and Fe(II) was investigated. The study was conducted at room temperature as a function of pH, initial concentration of the metals and contact time. Optimum sorption at pH of 2.0, 5.0 and 6.0 was observed for Fe (II), Cr (VI) and Pb (II) respectively. Adsorption removal efficiency increased proportionally to contact time and decreased as the initial concentration was increased. Langmuir and Freundlich isotherms were applied to model the process and good fitness was found for Langmuir R² > 9.5 with values of R_L<1. Pseudo second-order kinetic provided the best fit for the experimental data with calculated values of q_e almost equal to the experimental values. Chemical reaction was determined to be the primary mechanism of adsorption. Results indicated that animal shells could be employed as excellent adsorbents for the removal of heavy metals from wastewater pollutants.

Chinnalaptti a small village at Dindigul district of Tamil Nadu is famous for its Chungidi handllom sarees. Around 13 textile processing units are there in this village. This paper is an attempt to evaluate the physio-chemical characteristics of dye effluent such as Total Dissolved Solid TDS),Chemical Oxygen Demand (COD), Biological Oxygen Demand (COD) Total Hardness, Sulphate, Sodium, Potassium, Calcium, Magnesium, Copper, Zinc and Nickel.

Groundwater samples from the Ayensu Basin in the Central Region were investigated to ascertain the concentration of trace metals.  Twelve (12) trace metals were analysed in twenty nine (29) groundwater samples from the study area. Fe, Zn, Cd, Ni, Pb, Cr, Hg, and Ag were analysed using Atomic Absorption Spectrometer (AAS) whiles Cu, Al, Mn and As were determined by Instrumental Neutron Activation analysis (INAA). Cd, Ni, Pb, Cr, Hg, and Ag were found below detection limits of <0.002, <0.010, <0.010, <0.006, <0.001 and <0.002 respectively. The detectable trace metals measured mean concentrations in the order; Fe (1.136±0.336 mg/L) > Al (0.856±0.459 mg/L) > Cu (0.382±0.379 mg/L) > As (0.287±0.232 mg/L) > Mn (0.269±0.212 mg/L) > Zn(0.090±0.080 mg/L). Mean concentrations of Al, As and Fe exceeded the WHO limits of 0.2 mg/l, 0.01 mg/l and 0.3 mg/l for drinking water. The trace metals concentrations were found to be generally low and therefore the groundwater from the localities are suitable for domestic use.

Stable isotopes of ²H and ¹⁸O and physico-chemical data of groundwater and surface water from parts of the Ayensu Basin have been used to assess the origin of groundwater and the possible source of salinity in the groundwater. The pH of groundwaters ranges from 5.53-7.21; the groundwaters are between mildly acidic and slightly alkaline. Chloride concentration of the boreholes ranges between 49.985-399.876mg/L. The conductivity of groundwater samples also varied between 382-2140µS/cm while their total dissolved solids (TDS) varied between 164.9-913mg/L. The isotopic compositions of ? ¹⁸O versus ? ²H of the groundwaters plotted along the local meteoric water line indicating that the groundwaters do not undergo significant evaporation before recharge. The plot of ? ¹⁸O versus chloride indicates that processes for the increasing salinity could be due to enrichment by evaporation and possibly dissolution of soil salts. The study has also shown that the aquifers could be discontinuous.

The article extends, study on the removal of heavy metals such as Cr, Zn and Ni from tannery effluent by using macrofungi in the form of mycelial biomass. Mycelial biomass of cultivated mushrooms namely Pleurotus florida, Calocybe indica were collected and subjected for biosorption studies. Among the chosen two mushrooms Pleurotus florida showed the maximum biosorption. Both the mushrooms were found to have the biosorption efficiency of heavy metals namely Cr, Zn and Ni. Pleurotus florida has 88.5%biosorption efficiency of Cr; 68.4% Zn and 58.8%; while Calocybe indica has recorded 55%biosorption of efficiency of Cr;37.9% Zn and 49.1% Ni respectively. As biosorption of heavy metals using macrofungi is an ecofriendly method, it could be an excellent and viable method for the removal of heavy metals form tannery effluent.

The present investigation was carried in the experimental test organism, Mugil cephalus exposed to cadmium, copper, lead and zinc in acute and chronic toxicity test. The raw survival data from the acute toxicity test were utilized for the prediction of No Observed Effect Concentration (NOEC). The data obtained from the laboratory and the predicted endpoints were then compared with the heavy metal concentrations in the Ennore creek. Acute toxicity tests revealed that fingerlings were sensitive to copper, followed by cadmium, lead and zinc, and the 96-hour LC₅₀ values were 4.29 mg/l Cd, 2.29 mg/l Cu, 6.90 mg/l Pb and 7.92 mg/l Zn. Experimental NOEC had strong correlation with the predicted NOEC at P=0.0001 and P=0.005. Correlations were significant at P<0.01 (2-tailed), (? =0.05). The predicted and the experimental NOEC values were lower than the heavy metal concentrations in the Ennore creek. The concentrations of heavy metals in the Ennore creek were relatively higher than the NOEC values for juvenile marine organisms tested in the laboratory. Hence, there exists threat for survival and an urgent need for the enactment and enforcement of stringent laws to control the heavy metal pollution in the Ennore creek as well as to protect estuarine and marine bio-resources.

The environmental stable isotopic (oxygen-18 and hydrogen-2)  composition of groundwater  in the crystalline geological formation underlying the Accra Plains of South-east Ghana were studied to obtain information on the recharge process.  The groundwater had an average isotopic value of –3.19‰ ?¹⁸O and –14.36‰ ?²H. The groundwater recharge takes place in fractures with the occurrence of minor evaporation. The groundwater was also affected by the mixing of various rainfall events and or surface runoff. The groundwaters at Valley View University were more depleted than the other groundwaters in the Plains indicating that the groundwater was recharge at the Akwapim Togo Mountains through preferential channels.