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911.
Prawn aquaculture industry is one of the developing economic activities in the Philippines. Generally, a wide range of microalgae typically grow and proliferate in many aquaculture ponds. However, certain species of microalgae have the ability to form harmful algal blooms (HABs) which often bring damaging consequences to the aquaculture industry, food safety, and the environment. The study aims to identify and characterize the composition of microalgae (particularly Cyanophyta) that are capable of forming HABs in selected freshwater prawn culture ponds in Central Luzon, Philippines, using morphological, ultrastructural, and molecular characterizations. From water samples collected in ten selected ponds across Central Luzon (Bulacan, Nueva Ecija, Pampanga, Tarlac, and Zambales), potential HAB formers such as Oscillatoria agardhii, O. princeps, Microcystis aeruginosa, and M. wesenbergii were observed to have occurred mostly, while Anabaena circinalis was only observed in one site. Both morphological and ultrastructural methods brought upon some challenges and limitations while molecular methods using 16S rRNA gene and phylogenetic analysis which were optimized in this study offered better and more efficient ways of identification and were helpful in resolving genus-level and species-level relationships. The influence of physicochemical properties of pond water, especially nutrient levels (nitrate, nitrite, and orthophosphate) on the occurrence of these cyanobacteria was also analyzed. As a pioneering study on freshwater HABs in aquaculture ponds in the country, results of the study can provide information to improve the knowledge in bloom occurrence and prediction, and to develop freshwater HAB prevention and control methods.  相似文献   
912.
Despite the often mentioned environmental benefits associated with transition from fossil fuels to renewable energy sources, their use for electricity production has non-negligible negative environmental impacts. The most commonly mentioned in surveys concern different types of landscape impacts, impacts on the fauna and flora, and noise. These impacts differ by size and location of plants, and by source of energy, rendering the policy decision complex. In addition, there are other welfare issues to take into consideration, as positive and negative environmental impacts are not evenly distributed among population groups. This paper proposes to compare the welfare impacts of renewable energy sources controlling for the type of renewable as well as the specific environmental impact by source. To this end, two discrete-choice experiments are designed and applied to a national sample of the Portuguese population. In one case, only individual negative impacts of renewables are used, and in another case, the negative impacts interact with a specific source. Results show the robustness of discrete-choice experiments as a method to estimate the welfare change induced by the impacts of renewable energy sources. Overall, respondents are willing to pay to reduce the environmental impacts, thus making compensation for local impacts feasible. Moreover, the estimations reveal that respondents are significantly sensitive to the detrimental environmental effects of specific renewable energy sources, being willing to pay more to use these sources of energy relative to others.  相似文献   
913.
914.
On-line in-tube solid phase microextraction (in-tube SPME) coupled to high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS) was successfully applied to the determination of selected triazines in water samples. The method based on the employment of a packed column containing graphene oxide (GO) supported on aminopropyl silica (Si) showed that the extraction phase has a high potential for triazines extraction aiming to its physical-chemical properties including ultrahigh specific surface area, good mechanical and thermal stability and high fracture strength. Injection volume and loading time were both investigated and optimized. The method validation using Si-GO to extract and concentrate the analytes showed satisfactory results, good sensitivity, good linearity (0.2–4.0 µg L?1) and low detection limits (1.1–2.9 ng L?1). The high extraction efficiency was determined with enrichment factors ranging from 1.2–2.9 for the lowest level, 1.3–4.9 intermediate level and 1.2–3.0 highest level (n = 3). Although the analytes were not detected in the real samples evaluated, the method has demonstrated to be efficient through its application in the analysis of spiked triazines in ground and mineral water samples.  相似文献   
915.
Winter manure application elevates nutrient losses and impairment of water quality as compared to manure applications in other seasons. In conjunction with reviewing global distribution of animal densities, we reviewed worldwide mandatory regulations and voluntary guidelines on efforts to reduce off-site nutrient losses associated with winter manure applications. Most of the developed countries implement regulations or guidelines to restrict winter manure application, which range from a regulative ban to guidelines based upon weather and field management conditions. In contrast, developing countries lack such official directives, despite an increasing animal production industry and concern over water quality. An analysis of five case studies reveals that directives are derived from a common rationale to reduce off-site manure nutrient losses, but they are also affected by local socio-economic and biophysical considerations. Successful programs combine site-specific management strategies along with expansion of manure storage to offer farmers greater flexibility in winter manure management.  相似文献   
916.
One of the highest self-reported incidence rates of acute gastrointestinal illness (AGI) in the global peer-reviewed literature occurs in Inuit communities in the Canadian Arctic. This high incidence of illness could be due, in part, to the consumption of contaminated water, as many northern communities face challenges related to the quality of municipal drinking water. Furthermore, many Inuit store drinking water in containers in the home, which could increase the risk of contamination between source and point-of-use (i.e., water recontamination during storage). To examine this risk, this research characterized drinking water collection and storage practices, identified potential risk factors for water contamination between source and point-of-use, and examined possible associations between drinking water contamination and self-reported AGI in the Inuit community of Rigolet, Canada. The study included a cross-sectional census survey that captured data on types of drinking water used, household practices related to drinking water (e.g., how it was collected and stored), physical characteristics of water storage containers, and self-reported AGI. Additionally, water samples were collected from all identified drinking water containers in homes and analyzed for presence of Escherichia coli and total coliforms. Despite municipally treated tap water being available in all homes, 77.6% of households had alternative sources of drinking water stored in containers, and of these containers, 25.2% tested positive for total coliforms. The use of transfer devices and water dippers (i.e., smaller bowls or measuring cups) for the collection and retrieval of water from containers were both significantly associated with increased odds of total coliform presence in stored water (ORtransfer device = 3.4, 95% CI 1.2–11.7; ORdipper = 13.4, 95% CI 3.8–47.1). Twenty-eight-day period prevalence of self-reported AGI during the month before the survey was 17.2% (95% CI 13.0–22.5), which yielded an annual incidence rate of 2.4 cases per person per year (95% CI 1.8–3.1); no water-related risk factors were significantly associated with AGI. Considering the high prevalence of, and risk factors associated with, indicator bacteria in drinking water stored in containers, potential exposure to waterborne pathogens may be minimized through interventions at the household level.  相似文献   
917.
A thermal/optical carbon analyzer (TOA), normally used for quantification of organic carbon (OC) and elemental carbon (EC) in PM2.5 (fine particulate matter) speciation networks, was adapted to direct thermally evolved gases to an electron impact quadrupole mass spectrometer (QMS), creating a TOA-QMS. This approach produces spectra similar to those obtained by the Aerodyne aerosol mass spectrometer (AMS), but the ratios of the mass to charge (m/z) signals differ and must be remeasured using laboratory-generated standards. Linear relationships are found between TOA-QMS signals and ammonium (NH4+), nitrate (NO3?), and sulfate (SO42-) standards. For ambient samples, however, positive deviations are found for SO42-, compensated by negative deviations for NO3?, at higher concentrations. This indicates the utility of mixed-compound standards for calibration or separate calibration curves for low and high ion concentrations. The sum of the QMS signals across all m/z after removal of the NH4+, NO3?, and SO42- signals was highly correlated with the carbon content of oxalic acid (C?H?O?) standards. For ambient samples, the OC derived from the TOA-QMS method was the same as the OC derived from the standard IMPROVE_A TOA method. This method has the potential to reduce complexity and costs for speciation networks, especially for highly polluted urban areas such as those in Asia and Africa.

Implications: Ammonium, nitrate, and sulfate can be quantified by the same thermal evolution analysis applied to organic and elemental carbon. This holds the potential to replace multiple parallel filter samples and separate laboratory analyses with a single filter and a single analysis to account for a large portion of the PM2.5 mass concentration.  相似文献   
918.
Selection of appropriate residue application method is essential for better use of biomass for soil and environmental health improvement. A laboratory incubation experiment was conducted for 75 days to investigate C and N mineralization of residues of soybean (Glycine max L.), chickpea (Cicer arietinum L.), maize (Zea mays L.), and wheat (Triticum aestivum L.) placed on the soil surface and incorporated into the soil. The residue of soybean and chickpea had a greater decomposition rate than that of maize and wheat, despite of their placements. Higher rate of decomposition of the residue of soybean and chickpea was recorded when it was kept on the soil surface while soil incorporation of residue of wheat and maize resulted in faster decomposition. Therefore, these findings could be used as guidelines for management of crop residue application in farmland to improve soil and environmental quality.  相似文献   
919.
Copper mine tailings pose many threats to the surrounding environment and human health, and thus, their remediation is fundamental. Coal spoil is the waste by-product of coal mining and characterized by low levels of metals, high content of organic matter, and many essential microelements. This study was designed to evaluate the role of coal spoil on heavy uptake and physiological responses of Lolium perenne L. grown in copper mine tailings amended with coal spoil at rates of 0, 0.5, 1, 5, 10, and 20%. The results showed that applying coal spoil to copper mine tailings decreased the diethylenetriaminepentaacetic acid (DTPA)-extractable Cd, Cu, Pb, and Zn contents in tailings and reduced those metal contents in both roots and shoots of the plant. However, application of coal spoil increased the DTPA-extractable Cr concentration in tailings and also increased Cr uptake and accumulation by Lolium perenne L. The statistical analysis of physiological parameters indicated that chlorophyll and carotenoid increased at the lower amendments of coal spoil followed by a decrease compared to their respective controls. Protein content was enhanced at all the coal spoil amendments. When treated with coal spoil, the activities of superoxide dismutases (SOD), peroxidase (POD), and catalase (CAT) responded differently. CAT activity was inhibited, but POD activity was increased with increasing amendment ratio of coal spoil. SOD activity increased up to 1% coal spoil followed by a decrease. Overall, the addition of coal spoil decreased the oxidative stress in Lolium perenne L., reflected by the reduction in malondialdehyde (MDA) contents in the plant. It is concluded that coal spoil has the potential to stabilize most metals studied in copper mine tailings and ameliorate the harmful effects in Lolium perenne L. through changing the physiological attributes of the plant grown in copper mine tailings.  相似文献   
920.
Seven years (2010–2016) of data on the basic physicochemical properties of seawater, temperature, salinity, dissolved oxygen (DO), nutrients, chlorophyll a (Chl a), and hydrocarbons from two lagoons were used to evaluate the impact of the anthropogenic activities inside the lagoon on the water quality and to explore the relationship of any impact from the lagoons’ design. Statistical analysis shows the modification in water quality inside the lagoon compared to the ambient seawater is particularly evident for nitrate, silicate, and Chl a. The modification is attributed to the extensive boat activities in the lagoons and the limited water exchange between the lagoons and ambient seawater. However, the impact to both lagoons is generally limited to inside the lagoons. The oligotrophic state of the two lagoons was evaluated and it was found that the most marked code violations were found in DIN inside both lagoons. In order to explore the design importance, the water exchange and overall water quality was compared between the two lagoons. This study highlights the importance of an environmental design study before the construction of any lagoon project. Proper design would maintain acceptable water quality inside the lagoons, critical for environmental health and supporting continued recreational activities.  相似文献   
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