Applications of chitosan in food,pharmaceuticals, medicine,cosmetics, agriculture,textiles, pulp and paper,biotechnology, and environmental chemistry

Environmental Chemistry Letters - Chitosan is a biopolymer obtained from chitin, one of the most abundant and renewable materials on Earth. Chitin is a primary component of cell walls in fungi, the...     

Seaweed for climate mitigation,wastewater treatment,bioenergy, bioplastic,biochar, food,pharmaceuticals, and cosmetics: a review

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

     

Regulator reputation, enforcement, and environmental compliance

This paper explores empirically the impact of enforcement efforts on environmental compliance, focusing on the role of regulator reputation spillover effects. We find that, on the margin, the impact of a fine for water pollutant violations is about a two-thirds reduction in the statewide violation rate in the year following a fine. This large result obtains through the regulator's enhanced reputation; the deterrence impact on other plants in a state is almost as strong as the impact on the sanctioned plant. Focusing only on the response of the sanctioned plant, as in previous studies, may therefore seriously underestimate the efficacy of fines and other sanctions. This paper also examines the relative effectiveness of monitoring and enforcement instruments. Non-monetary sanctions contribute no detected impact on compliance, and the marginal fine induces substantially greater compliance than the marginal inspection.     

Crime,weather, and climate change

This paper estimates the impact of climate change on the prevalence of criminal activity in the United States. The analysis is based on a 30-year panel of monthly crime and weather data for 2997 US counties. I identify the effect of weather on monthly crime by using a semi-parametric bin estimator and controlling for state-by-month and county-by-year fixed effects. The results show that temperature has a strong positive effect on criminal behavior, with little evidence of lagged impacts. Between 2010 and 2099, climate change will cause an additional 22,000 murders, 180,000 cases of rape, 1.2 million aggravated assaults, 2.3 million simple assaults, 260,000 robberies, 1.3 million burglaries, 2.2 million cases of larceny, and 580,000 cases of vehicle theft in the United States.     

Research progress on distribution,sources, identification,toxicity, and biodegradation of microplastics in the ocean,freshwater, and soil environment

• Microplastics are widely found in both aquatic and terrestrial environments. • Cleaning products and discarded plastic waste are primary sources of microplastics. • Microplastics have apparent toxic effects on the growth of fish and soil plants. • Multiple strains of biodegradable microplastics have been isolated. Microplastics (MPs) are distributed in the oceans, freshwater, and soil environment and have become major pollutants. MPs are generally referred to as plastic particles less than 5 mm in diameter. They consist of primary microplastics synthesized in microscopic size manufactured production and secondary microplastics generated by physical and environmental degradation. Plastic particles are long-lived pollutants that are highly resistant to environmental degradation. In this review, the distribution and possible sources of MPs in aquatic and terrestrial environments are described. Moreover, the adverse effects of MPs on natural creatures due to ingestion have been discussed. We also have summarized identification methods based on MPs particle size and chemical bond. To control the pollution of MPs, the biodegradation of MPs under the action of different microbes has also been reviewed in this work. This review will contribute to a better understanding of MPs pollution in the environment, as well as their identification, toxicity, and biodegradation in the ocean, freshwater, and soil, and the assessment and control of microplastics exposure.     

Metal passivity as mechanism of metal carcinogenesis: Chromium,nickel, iron,copper, cobalt,platinum, molybdenum

For the transition metals chromium, nickel, iron, copper, cobalt, platinum, and molybdenum, mechanisms of stable bonding in biochemistry (emphasis on carcinogenic mechanisms), chemistry, industrial chemistry, as well as epidemiological, occupational, orthopedic (implant devices) effects related to carcinogenesis, were reviewed. Hypothetically, the propensity to stable bonding (inertness), which ensures the metals’ performance capacity for consumers and industrial application, relates to their carcinogenicity. For chromium, a relationship between industrial/chemical and biological reactivity was noted for the tendency of Cr(III) ions to cause hydrolysis previous to stable bonding, as occurs during anodic passivation, leather tanning, and as indicated in biochemical studies pertaining to a mechanism of DNA condensation, which was suggested as a carcinogenic mechanism. The involvement of metal hydrolysis in both anodic passivation and biochemistry was noted also for nickel, iron, and platinum; the DNA interaction of platinum (cis-platin) is known to depend on hydrolysis. For nickel, issues of potential (V) were found important in both passivation and carcinogenicity. Comparably, the passivity behavior of cobalt and copper was found atypical, and their carcinogenicity yet unclear. Molybdenum, contained in passivated metallic implants, may relate to implant-associated carcinogenesis. Occupational carcinogenic effects were indicated for chromium, nickel, iron, and cobalt as caused by both reactive and passivated metal species. Exposure to acids and chronic respiratory irritation/infection/inflammation in workers were important cofactors in metal carcinogenesis. For wood and leather workers exposed to dust, the assumed presence in dust of metal particles abraded from alloys (sawing or cutting blades) may be a carcinogenic exposure hazard.     

Climatic Change, Wildfire, and Conservation

Abstract:  Climatic variability is a dominant factor affecting large wildfires in the western United States, an observation supported by palaeoecological data on charcoal in lake sediments and reconstructions from fire-scarred trees. Although current fire management focuses on fuel reductions to bring fuel loadings back to their historical ranges, at the regional scale extreme fire weather is still the dominant influence on area burned and fire severity. Current forecasting tools are limited to short-term predictions of fire weather, but increased understanding of large-scale oceanic and atmospheric patterns in the Pacific Ocean (e.g., El Niño Southern Oscillation, Pacific Decadal Oscillation) may improve our ability to predict climatic variability at seasonal to annual leads. Associations between these quasi-periodic patterns and fire occurrence, though evident in some regions, have been difficult to establish in others. Increased temperature in the future will likely extend fire seasons throughout the western United States, with more fires occurring earlier and later than is currently typical, and will increase the total area burned in some regions. If climatic change increases the amplitude and duration of extreme fire weather, we can expect significant changes in the distribution and abundance of dominant plant species in some ecosystems, which would thus affect habitat of some sensitive plant and animal species. Some species that are sensitive to fire may decline, whereas the distribution and abundance of species favored by fire may be enhanced. The effects of climatic change will partially depend on the extent to which resource management modifies vegetation structure and fuels.     

Pharmaceuticals,endocrine disruptors,personal care products,nanomaterials and perfluorinated pollutants: a review

The presence of emerging micropollutants such as pharmaceuticals, endocrine disruptors, personal care products, nanomaterials and perfluorinated substances in the environment remains a great threat to the health and safety of humans and aquatic species. These micropollutants enter the environment via anthropogenic activities and have been detected in surface water, groundwater and even drinking water at nanogram per litre to microgram per litre concentration. To date, limited information exists on the fate, behaviours, and pathways of these micropollutants in the environment. The potential ecotoxicological effects on the receptors due to exposure to individual or mixture of these chemicals still remain unknown. This review provides an overview on pharmaceuticals, endocrine disrupting compounds, personal care products, nanomaterials and perfluorinated pollutants, with emphasis on their occurrences, effects, environmental fates, and potential risk of exposure in water, soil or sediment. Based on the literature survey, it was found that in spite of an extensive research and different developmental efforts on the challenges of emerging micropollutants, the solution to the problem of emerging micropollutants in the environment is far from being solved. The needs for behavioural change among citizens, strong political will and policy formulation on the part of government are identified as possible panacea for combating the growing influence of these potential damaging substances. Suggestions on proactive and precautionary measures that must be taken to protect the environment as well as guarantee the health and safety of humans and aquatic species are provided. Future research should concentrate on the development of a risk based screening models and framework that can predict the sources, fate and behaviours of emerging contaminants in the environment is recommended.     

Fragmentation of Phragmites Habitats, Minimum Viable Population Size, Habitat Suitability, and Local Extinction of Moths, Midges, Flies, Aphids, and Birds

Results from populations of insects and birds inhabiting Phragmites habitats were used to analyze effects of fragmentation. Flush-crash cycles of the stem-boring moth Archanara geminipuncta (Lepidoptera, Noctuidae) showed regionally concurrent, local extinctions despite an originally enormous population size (more than 180,000 adults), emphasizing the importance of metapopulation dynamics. Further, A. geminipuncta could be considered a keystone species, since shoot damage facilitated more than twenty species of herbivores, saprovores (of the caterpillars' feces), and their parasitoids. The gall midge Lasioptera arundinis could survive only in side shoots induced by shoot damage of A. geminipuncta .
Small Phragmites stands had thinner shoots (due to a water or nutrient deficiency) and shoots with more leaves (due to a better light supply) than large stands, thereby influencing species-specific demands for habitat suitability and nutritiousness of reed tissue. In other words significance of habitat fragmentation could not be assessed by area alone. For example, two chloropid flies depending on thin, yellowish shoots survived only in small habitats or in the unmown edges of large habitats.
Local persistence of Phragmites herbivores depended on much larger population sizes than could be expected from a population size sufficient to maintain genetic variation. At least 11,000 adults of the gall midge Giraudiella inclusa (or more than 84,000 galls) were necessary to avoid local extinction.
With regard to conservation management of reed habitats, nature reserves should consist of old and unmown reeds, have fewer disturbed (particularly, fewer mown) habitat edges, measure more than two hectares (priority should go to the largest remaining fragments), and be surrounded by nearby reed habitats providing reservoir populations and diverse shoot types.     

Plant vintage, technology, and environmental regulation

We use data on productivity and pollution abatement costs at individual pulp and paper mills to test whether the impact of environmental regulation on productivity differs by plant vintage and technology. Plants with higher pollution abatement costs have significantly lower productivity levels. This relationship differs greatly based on a plant's technology, with productivity at integrated mills being greatly affected by abatement costs, while the impact at non-integrated mills is negligible. Plant vintage does not seem to matter, with older and newer plants showing similar impacts. Reported abatement costs appear to substantially understate the true costs of abatement. Accounting for the impact of technology differences makes some difference in the estimated overall impact of environmental regulation.     

Externalities, pigouvian corrections, and risk attitudes

We examine the influence of risk attitudes on the provision of an externality and on the proper size of Pigouvian correction when the externality is a random variable whose distribution is affected by an observable externality-generating activity. An intervening technology relates changes in this observable activity to the probability distribution of the relevant externality. Unlike the now-standard result in the theory of the firm involving the influence of risk attitudes on output levels, we cannot conclude that increases in risk aversion will lead necessarily to a reduction in the level of the externality. Our results are applied to a wide range of market failures.     

Concentrations of V,Cr, Mn,Fe, Ni,Co, Cu,Zn, As and Cd in mesopelagic crustaceans from the North East Atlantic Ocean

Specimens of oceanic decapods, mysids and euphausiids, collected from the North East Atlantic Ocean during July 1985, were analysed for V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As and Cd. Measurement of the metals was carried out using two techniques: inductively-coupled plasma-source mass spectrometry (ICP-MS) and atomic absorption (AAS). With the exception of the iron data, good agreement was observed between the data from the two techniques. Baseline-metal data are presented for the species measured, along with any effects of animal size on metal concentration. The data presented for oceanic animals from different trophic levels are important in studies of metal fluxes and for the assessment of markers within the food web in the oceans.     

Conservation and the 4 Rs,which are rescue,rehabilitation, release,and research

Vertebrate animals can be injured or threatened with injury through human activities, thus warranting their “rescue.” Details of wildlife rescue, rehabilitation, release, and associated research (our 4 Rs) are often recorded in large databases, resulting in a wealth of available information. This information has huge research potential and can contribute to understanding of animal biology, anthropogenic impacts on wildlife, and species conservation. However, such databases have been little used, few studies have evaluated factors influencing success of rehabilitation and/or release, recommended actions to conserve threatened species have rarely arisen, and direct benefits for species conservation are yet to be demonstrated. We therefore recommend that additional research be based on data from rescue, rehabilitation, and release of animals that is broader in scope than previous research and would have community support.     

Stochastic bycatch, informational asymmetry, and discarding

The existing literature (i) examines bycatch and discard behavior in a static framework and (ii) treats bycatch as a deterministic process uniform across vessels. Using a dynamic representative agent model in a two-stock resource, this paper explores strategic interactions between a social planner and two groups of harvesters, one of which imposes a stochastic “technological externality” (bycatch) on the other. In addition to limitations on entry and the number of trips taken in each industry, three bycatch control instruments are compared to the unconstrained case: taxes, trip limits, and value-based quotas. Implementation and enforcement costs aside, taxes dominate both types of quota, and value limits outperform trip limits by eliminating one type of discarding. In simulations, relative performance depends upon variance in the bycatch process, differences in the ex vessel prices of stocks, relative efficiency of the harvester types, and fixed costs on the trip and industry margins.     

El Niño, Expectations, and Fishing Effort in Monterey Bay, California

This article uses vector autoregressions (VARs) and a dynamic linear rational expectations model to analyze the effects of sea surface temperatures and catch prices on fishing effort for albacore tuna, Chinook salmon, sablefish, and squid in Monterey Bay, California. The VAR results show that fluctuations in sea surface temperatures, including El Niño events, have significant effects on effort and prices for these fisheries. Estimation of the model shows that El Niño has positive effects on the abundance in Monterey Bay of albacore and negative effects on Chinook, sablefish, and squid. Testing of the model supports rational expectations by harvesters of albacore, Chinook, and sablefish but not squid. Test results also suggest that dynamic adjustment costs are not significant for albacore, Chinook, or sablefish fisheries.     

Hydrogen sulfide, bacteria, and fish: a unique, subterranean food chain

Photoautotrophs are generally considered to be the base of food webs, and habitats that lack light, such as caves, frequently rely on surface-derived carbon. Here we show, based on analysis of gut contents and stable isotope ratios of tissues (13C:12C and 15N:14N), that sulfur-oxidizing bacteria are directly consumed and assimilated by the fish Poecilia mexicana in a sulfide-rich cave stream in Tabasco state, Mexico. Our results provide evidence of a vertebrate deriving most of its organic carbon and nitrogen from in situ chemoautotrophic production, and reveals the importance of alternative energy production sources supporting animals in extreme environments.     

Hunting, law enforcement, and African primate conservation

Abstract: Primates are regularly hunted for bushmeat in tropical forests, and systematic ecological monitoring can help determine the effect hunting has on these and other hunted species. Monitoring can also be used to inform law enforcement and managers of where hunting is concentrated. We evaluated the effects of law enforcement informed by monitoring data on density and spatial distribution of 8 monkey species in Taï National Park, Côte d’Ivoire. We conducted intensive surveys of monkeys and looked for signs of human activity throughout the park. We also gathered information on the activities of law‐enforcement personnel related to hunting and evaluated the relative effects of hunting, forest cover and proximity to rivers, and conservation effort on primate distribution and density. The effects of hunting on monkeys varied among species. Red colobus monkeys (Procolobus badius) were most affected and Campbell's monkeys (Cercopithecus campbelli) were least affected by hunting. Density of monkeys irrespective of species was up to 100 times higher near a research station and tourism site in the southwestern section of the park, where there is little hunting, than in the southeastern part of the park. The results of our monitoring guided law‐enforcement patrols toward zones with the most hunting activity. Such systematic coordination of ecological monitoring and law enforcement may be applicable at other sites.     

Sensitivity of gametes, fertilization, and embryo development of the Japanese pearl oyster, Pinctada fucata martensii, to the harmful dinoflagellate, Heterocapsa circularisquama

Blooms of the toxic dinoflagellate Heterocapsa circularisquama cause massive bivalve kills in Japan. Mariculture of the Japanese pearl oyster, Pinctada fucata martensii, is the industry most affected by these blooms, especially in Ago Bay, Mie Prefecture, where they are frequent, cause mass mortality of oysters, and overlap with their spawning season. The goal of this August 2009 study was to assess the effects of a toxic strain of H. circularisquama isolated from Ago Bay on gametes, fertilization, and embryo development of pearl oysters. Spermatozoa, eggs, spermatozoa and eggs, and fertilized eggs of pearl oysters from Ago Bay were exposed to H. circularisquama at cell densities reported during the bloom (10–10⁴ cells mL^?1) for different periods of time. The concentration of H. circularisquama, exposure duration, and their interactions all had significant effects on gamete quality, fertilization, and embryo development. The motility and swimming velocity of spermatozoa, egg viability, fertilization, and embryo development rate were significantly reduced in all concentrations, with a cell density of 10 cells mL^?1 determined to be the critical density of H. circularisquama for deleterious effects. This is the first evidence of inimical effects of an HAB species on bivalve spermatozoa upon direct exposure. Further field and laboratory studies are required to investigate the potential effects of H. circularisquama blooms on the reproduction and recruitment of Japanese pearl oysters and other bivalves.     

Cardenolide content,emetic potency,and thin-layer chromatography profiles of monarch butterflies,Danaus plexippus,and their larval host-plant milkweed,Asclepias humistrata,in Florida

Summary This paper is the fourth in a series on cardenolide fingerprints of monarch butterflies (Danaus plexippus, Danainae) and their host-plant milkweeds (Asclepiadaceae) in the eastern United States. Cardenolide concentrations ofAsclepias humistrata plants from north central Florida ranged from 71 to 710 µg/0.1 g dry weight, with a mean of 417 µg/0.1 g. Monarchs reared individually on these plants contained cardenolide concentrations ranging from 243 to 575 µg/0.1 g dry weight, with a mean of 385 µg/0.1 g. Cardenolide uptake by butterflies was independent of plant concentration, suggesting that sequestration saturation occurs in monarchs fed cardenolide-rich host plants. Thinlayer chromatography resolved 19 cardenolides in the plants and 15 in the butterflies. In addition to humistratin,A. humistrata plants contained several relatively non-polar cardenolides of the calotropagenin series which are metabolized to more polar derivatives in the butterflies. These produced a butterfly cardenolide fingerprint clearly distinct from those previously established for monarchs reared on otherAsclepias species. In emetic assays with the blue jay,Cyanocitta cristata, the 50% emetic dose (ED₅₀) per jay was 57.1 µg, and the average number of ED₅₀ units per butterfly was 13.8, establishing that this important south eastern milkweed produces highly emetic, chemically defended monarchs. Our data provide further support for the use of cardenolide fingerprints of wild-caught monarchs to make ecological predictions concerning defence against natural enemies, seasonal movement and larval host-plant utilization by monarch butterflies during their annual cycle of migration, breeding and overwintering.     

苯、氯苯、苯酚、4-氯酚对斑马鱼、孔雀鱼、剑尾鱼的急性毒性

以斑马鱼（Zebra fish）Danio rerio、剑尾鱼Xiphophorus hellerii、孔雀鱼（Guppy）Poecilia reticulata为受试鱼种,采用半静态试验,考察苯、苯酚、氯苯、4-氯苯酚对3种鱼的急性毒性,结果表明,上述4种有机物对斑马鱼的96 h LC50分别为132.22、28.86、9.66、4.29 mg.L-1;对剑尾鱼的96 h LC50分别为123.76、27.25、8.86、4.29 mg.L-1;对孔雀鱼的96 h LC50分别为131.25、27.88、9.33、4.59 mg.L-1,都属于高毒物质。毒性大小为苯〈苯酚〈氯苯〈4-氯苯酚。毒性大小与取代基的类型有关,-Cl的毒性要大于-OH,-Cl和-OH的联合毒性大于单独的-Cl和-OH。孔雀鱼和剑尾鱼对上述有机污染物具有较好的敏感性,结果稳定,重现性好,可以作为急性毒性试验的受试鱼种。