Flow,Organic, and Inorganic Sediment Yields from a Channelized Watershed in the South Carolina Lower Coastal Plain

Many small streams in coastal watersheds in the southeastern United States are modified for agricultural, residential, and commercial development. In the South Carolina Lower Coastal Plain, low‐relief topography and a shallow water table make stream channelization ubiquitous. To quantify the impacts of urbanization and stream channelization, we measured flow and sediment from an urbanizing watershed and a small forested watershed. Flow and sediment export rates were used to infer specific yields from forested and nonforested regions of the urbanizing watershed. Study objectives were to: (1) quantify the range of runoff‐to‐rainfall ratios; (2) quantify the range of specific sediment yields; (3) characterize the quantity and quality of particulate matter exported; and (4) estimate sediment yield attributable to agriculture, development, and channelization activities in the urbanizing watershed. Our results showed that the urban watershed exported over five times more sediment per unit area compared with the forested watershed. Sediment concentration was related to flow flashiness in the urban watershed and to flow magnitude in the forested watershed. Sediments from the forested watershed were dominated by organic matter, whereas mineral matter dominated sediment from the urban stream. Our results indicated that a significant shift in sediment quality and quantity are likely to occur as forested watersheds are transformed by urbanization in coastal South Carolina.     

Distribution of lindane in plasma and brain after a single administration to cats

The distribution of lindane and its metabolites in the plasma and brain of the cats after 30 minutes, 1, 2, 4 and 8 hours of administration of lindane (2mg/kg, i.v.) was investigated. The compound distributes differentially in the CNS and this pattern changes with time. The pattern of distribution shows that although lindane concentration is higher in areas with a high myelin content, it disappears more rapidly from gray matter. The plasma levels were also high at 30 minutes interval and then gradually decreased. The rate of formation of the metabolite 2,4,6‐Trichlorophenol appeared to be maximum in the first 4 hours. The accumulation of the compound and its metabolite in brain during the experimental period was not evident.     

Influence of cadmium on the storage and metabolism of HCH in rats

Male albino rats were administered Cd and HCH daily for six weeks to study the effect of Cd on storage and metabolism of HCH. The results indicated a marked inhibition of the metabolism of HCH in the group dosed with HCH + Cd. The metabolic rate of HCH in the group dosed with HCH + Cd was also significantly lower than that in the group dosed with HCH alone. The hepatic content of Cd and Zn was significantly increased whereas a marked depletion of Cu and Fe was observed in the groups exposed to Cd and HCH + Cd. A high level of free Cd and Zn or a low level of Fe and Cu in liver seemed to play an important role in the metabolic inhibition observed in this study.     

Biotechnological methods to remove microplastics: a review

Environmental Chemistry Letters - Microplastics pollution is major threat to ecosystems and is impacting abiotic and biotic components. Microplastics are diverse and highly complex...     

Patterns of insect communities along a stress gradient following decommissioning of a Cu-Ni smelter

The diversity, estimated richness and abundance of terrestrial insect communities were examined along a stress gradient of past pollution in the region of Sudbury, Ontario, Canada. This gradient represents the natural recovery and lingering effects of a decommissioned copper-nickel smelting complex. Ant genera and sixteen higher taxonomic groups (family and order) had the highest abundance at the sites with intermediate stress. Eight families increased in abundance with distance from the decommissioned source of pollution and eleven families decreased reflecting a complex response of diversity to pollution. Carabid beetles show an increase in diversity further from the smelter; however, examination of the species composition reveals a distinct carabid community closest to the smelter, emphasizing the unique habitat created by severe pollution. Although almost forty years since decomissioning of the smelter complex, the terrestrial insect community in the vicinity remains significantly impacted suggesting slow recovery.     

Biosorption kinetics of heavy metals by leaf biomass of Jatropha curcas in single and multi-metal system

Biosorption of Cu²⁺, Zn²⁺, and Cr⁶⁺ from aqueous solutions by leaf biomass of Jatropha curcas was investigated as a function of biomass concentration, initial metal ion concentration, contact time, and pH of the solution systematically. The aim of this study was to optimize biosorption process and find out a suitable kinetic model for the metal removal in single and multi-metal system. The experimental data were analyzed using two sorption kinetic models, viz., pseudo-first- and pseudo-second-order equations, to determine the best fit equation for the biosorption of metal ions Cu²⁺, Zn²⁺, and Cr⁶⁺ onto the leaf biomass of J. curcas in different metal systems. The experimental data fitted well the pseudo-second-order equation and provided the best correlation for the biosorption process. The findings of the present investigation revealed that J. curcas leaf biomass was an eco-friendly and cost-effective biosorbent for the removal of heavy metal ions from wastewater.     

Tropical storm off Myanmar coast sweeps reefs in Ritchie’s Archipelago, Andaman

The reefs in some islands of Andaman and Nicobar suffered severe damage following a tropical storm in the Bay of Bengal off Myanmar coast during 13–17 March 2011. Surveys were conducted at eight sites in Andaman, of which five were located in the Ritchie’s Archipelago where maximum wind speeds of 11 m?s^-1 was observed; and three around Port Blair which lay on the leeward side of the storm and had not experienced wind speeds of more than 9 m?s^-1. Corals in the shallow inshore reefs were broken and dislodged by the thrust of the waves. Significant damage in the deeper regions and offshore reefs were caused by the settlement of debris and sand brought down from the shallower regions. The fragile branching corals (Acropora sp.) were reduced to rubbles and the larger boulder corals (Porites sp.) were toppled over or scarred by falling debris. The reefs on the windward side and directly in the path of the storm winds were the worst affected. The investigation exposes the vulnerability of the reefs in Andaman to the oceanographic features which generally remain unnoticed unless the damage is caused to the coastal habitats.     

Effect of hypobaric hypoxia on visual evoked potential at high altitude

The effect of hypobaric hypoxia on visual evoked potential (VEP) was studied in 27 male volunteers at sea level (SL), during the 1st and 3rd weeks of their stay at high altitude (HA) of 3,500 m and in the 1st week of their return to the sea level (RSL). Exposure to high altitude (HA) led to significant changes in VEP. The N1 wave latency of both right and left eye was significantly increased (P<0.05) during 3rd week of stay at the altitude which persisted even after the return to the sea level. The latency of P1 wave of both right and left eye was higher in 3rd week at high altitude but not significant statistically. But the delay in P1 latency persisted in 1st week of their return to sea level which was significant (p<0.05) statistically as compared to sea level. The latency of N2 wave was significantly decreased (P<0.05) during the 1st week of stay at HA and returned back to basal value in the 3rd week of stay at HA in both right and left eye. However, the changes observed in NPN complex in terms of wave latencies were within the physiological limits. The amplitude of wave N1-P1 of both the right and left eye did not show any change. The changes observed reflect the process of acclimatisation to 3500m high altitude.     

Methodology for identifying vulnerability hotspots to tropical cyclone hazard in India

Vulnerability indices are commonly used for characterizing the impacts on a region or comparing relative vulnerability across regions. Such indices are usually computed as a composite/aggregate across different components of vulnerability. Though such a single numerical value can be useful in many situations, a major disadvantage is that it leads to loss of information about how the different factors that went into making the composite index interact with each other, and contribute to making a place vulnerable. In this paper we develop an alternative approach for identifying hotspots, based on cluster analysis that seeks to address this problem by considering the different components of vulnerability separately. We compute different indices for each of the components of vulnerability. Cluster analysis helps in identifying the most vulnerable districts based on different combinations of the components of vulnerability. In addition to being methodologically more robust than the index approach, the clustering approach may have greater policy-relevance as it provides information about which aspects of vulnerability, policy needs to address in the most vulnerable districts. An erratum to this article can be found at     

Evaluation of the mutagenic potential of chlorpyrifos (CPF) using polytene chromosomes of Anopheles mosquito

Diverse cytogenetic tests are employed for short term screening of suspect environmental mutagens by using insects and mammals as models. In the present paper the polytene chromosomes of a mosquito Anopheles maculatus were used to evaluate the mutagenic potential of a widely used organophosphate pesticide chlorpyrifos-[o, o-diethyl-o-(3, 5, 6-trichloro-2-pyridyl) phosphothioate]. The results are based on the frequency of various structural aberrations encountered in the polytene chromosomes of the larvae treated with LC20 of chlorpyrifos (CPF). These aberrations were dominated by inversions, stickiness of the chromosomes, heterochromatinization of the bands and lack of polyteny. The frequency of various aberrations was highest in the left arm of chromosome number 2L followed by 2R, 3L, 3R, and X-chromosomes i.e. 2.10 +/- 0.44, 1.84 +/- 0.44, 1.57 +/- 0.54, 1.31 +/- 0.50, and 0.22 +/- 0.27 respectively. The susceptibility of different chromosomal arms to this pesticide was 2L > 2R > 3L > 3R > X and the regions prone to these aberrations have been marked on the polytene chromosome map of Anopheles maculatus.