Effects of repeated-low level sodium chlorate administration on ruminal and fecal coliforms in sheep

Abstract

The objective of this study was to evaluate the efficacy of oral sodium chlorate administration on reducing total coliform populations in ewes. A 30% sodium chlorate product or a sodium chloride placebo was administered to twelve lactating Dorper X Blackbelly or Pelibuey crossbred ewes averaging 65 kg body weight. The ewes were adapted to diet and management. Ewes were randomly assigned (4/treatment) to one of three treatments which were administered twice daily by oral gavage for five consecutive days: a control (TC) consisting of 3 g sodium chloride/animal/d, a T3 treatment consisting of 1.8 g of sodium chlorate/animal/d, and a T9 treatment consisting of 5.4 g sodium chlorate/animal/d; the latter was intended to approximate a lowest known effective dose. Ruminal samples collected by stomach tube and freshly voided fecal samples were collected daily beginning 3 days before treatment initiation and for 6 days thereafter. Contents were cultured quantitatively to enumerate total coliforms. There were no significant differences in total coliform numbers (log₁₀ cfu/g) in the feces between treatments (P = 0.832). There were differences (P < 0.02) in ruminal coliform counts (log₁₀ cfu/mL) between treatments (4.1, 4.3 and 5.0 log₁₀/mL contents in TC, T3 and T9 Treatments, respectively) which tended to increase from the beginning of treatment until the 5th day of treatment (P < 0.05). Overall, we did not obtain the expected results with oral administration of sodium chloride at the applied doses. By comparing the trends in coliform populations in the rumen contents in all treatments, there was an increase over the days. The opposite trend occurred in the feces, due mainly to differences among rumen contents and feces in ewes administered the T9 treatment (P = 0.06). These results suggest that the low chlorate doses used here were suboptimal for the control of coliforms in the gastrointestinal tract of ewes.     

Assessing chlorinated ethene degradation in a large scale contaminant plume by dual carbon-chlorine isotope analysis and quantitative PCR

The fate of chlorinated ethenes in a large contaminant plume originating from a tetrachloroethene (PCE) source in a sandy aquifer in Denmark was investigated using novel methods including compound-specific carbon and chlorine isotope analysis and quantitative real-time polymerase chain reaction (qPCR) methods targeting Dehaloccocoides sp. and vcrA genes. Redox conditions were characterized as well based on concentrations of dissolved redox sensitive compounds and sulfur isotopes in SO(4)(2-). In the first 400 m downgradient of the source, the plume was confined to the upper 20 m of the aquifer. Further downgradient it widened in vertical direction due to diverging groundwater flow reaching a depth of up to 50 m. As the plume dipped downward and moved away from the source, O(2) and NO(3)(-) decreased to below detection levels, while dissolved Fe(2+) and SO(4)(2-) increased above detectable concentrations, likely due to pyrite oxidation as confirmed by the depleted sulfur isotope signature of SO(4)(2-). In the same zone, PCE and trichloroethene (TCE) disappeared and cis-1,2-dichloroethene (cDCE) became the dominant chlorinated ethene. PCE and TCE were likely transformed by reductive dechlorination rather than abiotic reduction by pyrite as indicated by the formation of cDCE and stable carbon isotope data. TCE and cDCE showed carbon isotope trends typical for reductive dechlorination with an initial depletion of (13)C in the daughter products followed by an enrichment of (13)C as degradation proceeded. At 1000 m downgradient of the source, cDCE was the dominant chlorinated ethene and had reached the source δ(13)C value confirming that cDCE was not affected by abiotic or biotic degradation. Further downgradient (up to 1900 m), cDCE became enriched in (13)C by up to 8 ‰ demonstrating its further transformation while vinylchloride (VC) concentrations remained low (<1 μg/L) and ethene was not observed. The correlated shift of carbon and chlorine isotope ratios of cDCE by 8 and 3.9 ‰, respectively, the detection of Dehaloccocides sp genes, and strongly reducing conditions in this zone provide strong evidence for reductive dechlorination of cDCE. The significant enrichment of (13)C in VC indicates that VC was transformed further, although the mechanism could not be determined. The transformation of cDCE was the rate limiting step as no accumulation of VC occurred. In summary, the study demonstrates that carbon-chlorine isotope analysis and qPCR combined with traditional approaches can be used to gain detailed insight into the processes that control the fate of chlorinated ethenes in large scale plumes.     

Assessment of the trophic status of four coastal lagoons and one estuarine delta, eastern Brazil

Anthropogenic eutrophication of aquatic ecosystems continues to be one of the major environmental issues worldwide and also of Brazil. Over the last five decades, several approaches have been proposed to discern the trophic state and the natural and cultural processes involved in eutrophication, including the multi-parameter Assessment of Estuarine Trophic Status (ASSETS) index model. This study applies ASSETS to four Brazilian lagoons (Mundaú, Manguaba, Guarapina, and Piratininga) and one estuarine delta (Paraíba do Sul River), set along the eastern Brazilian coast. The model combines three indices based on the pressure–state–response (PSR) approach to rank the trophic status and forecast the potential eutrophication of a system, to which a final ASSETS grade is established. The lagoons were classified as being eutrophic and highly susceptible to eutrophication, due primarily to their longer residence times but also their high nutrient input index. ASSETS classified the estuary of the Paraíba do Sul river with a low to moderate trophic state (e.g., largely mesotrophic) and low susceptibility to eutrophication. Its nutrient input index was high, but the natural high dilution and flushing potential driven by river flow mitigated the susceptibility to eutrophication. Eutrophication forecasting provided more favorable trends for the Mundaú and Manguaba lagoons and the Paraíba do Sul estuary, in view of the larger investments in wastewater treatment and remediation plans. The final ASSETS ranking system established the lagoons of Mundaú as “moderate,” Manguaba as “bad,” Guarapina as “poor,” and Piratininga as “bad,” whereas the Paraíba do Sul River Estuary was “good.”     

Using fisher-contributed secondary fins to fill critical shark-fisheries data gaps

Developing-world shark fisheries are typically not assessed or actively managed for sustainability; one fundamental obstacle is the lack of species and size-composition catch data. We tested and implemented a new and potentially widely applicable approach for collecting these data: mandatory submission of low-value secondary fins (anal fins) from landed sharks by fishers and use of the fins to reconstruct catch species and size. Visual and low-cost genetic identification were used to determine species composition, and linear regression was applied to total length and anal fin base length for catch-size reconstruction. We tested the feasibility of this approach in Belize, first in a local proof-of-concept study and then scaling it up to the national level for the 2017–2018 shark-fishing season (1,786 fins analyzed). Sixteen species occurred in this fishery. The most common were the Caribbean reef (Carcharhinus perezi), blacktip (C. limbatus), sharpnose (Atlantic [Rhizoprionodon terraenovae] and Caribbean [R. porosus] considered as a group), and bonnethead (Sphyrna cf. tiburo). Sharpnose and bonnethead sharks were landed primarily above size at maturity, whereas Caribbean reef and blacktip sharks were primarily landed below size at maturity. Our approach proved effective in obtaining critical data for managing the shark fishery, and we suggest the tools developed as part of this program could be exported to other nations in this region and applied almost immediately if there were means to communicate with fishers and incentivize them to provide anal fins. Outside the tropical Western Atlantic, we recommend further investigation of the feasibility of sampling of secondary fins, including considerations of time, effort, and cost of species identification from these fins, what secondary fin type to use, and the means with which to communicate with fishers and incentivize participation. This program could be a model for collecting urgently needed data for developing-world shark fisheries globally. Article impact statement: Shark fins collected from fishers yield data critical to shark fisheries management in developing nations.     

Green Chemistry - Views and Strategies * (5 pp)

Background and Goal The object of Green Chemistry is the reduction of chemical pollutants flowing to the environment. The Chemistry and the Environment Division of EuCheMS has assumed Green Chemistry as one of its areas of interest, but one question to solve is where Green Chemistry should be placed within the context of Chemistry and the Environment. The concept of Green Chemistry, as primarily conceived by Paul Anastas and John Warner, is commonly presented through the Twelve Principles of Green Chemistry. However, these Twelve Principles, though fruit of a great intuition and common sense, do not provide a clear connection between aims, concepts, and related research areas of Green Chemistry. These two unsolved questions are the object of the present article.Discussion Green Chemistry is here placed as a part of Chemistry for the Environment, concerning the still non-existent pollutants. Indeed, the object of Green Chemistry is the reduction of pollution and risks by chemicals by avoiding their generation or their introduction into the biosphere. The distinction between pollutant chemicals and dangerous chemicals, along with the consideration of the exhaustion of fossil resources and the acknowledgement of the harmful effects of the chemicals employed in a great variety of activities, leads to the recognition of four general objectives for Green Chemistry. In order to accomplish these general objectives, a number of strategies, or secondary objectives and some fundamental concepts, namely, atomic economy, selectivity, potential harm or historical harm can be visualized. A connection is finally established between the strategies and current and future research areas of Green Chemistry.Conclusion The ultimate aim of green chemistry is to entirely cut down the stream of chemicals pouring into the environment. This aim seems unattainable at present, but progress in the green chemical research areas and their application through successive approaches will certainly provide safer specialty chemicals and much more satisfactory processes for the chemical industry.- * The basis of this peer-reviewed paper is a presentation at the 9th FECS Conference on ‘Chemistry and Environment’, 29 August to 1 September 2004, Bordeaux, France.     

Selection of woody species for wastewater enhancement and restoration of riparian woodlands

Growth and nutrient uptake of seven tree species were evaluated with the goal of selecting the species that can be used for wastewater enhancement by dendro-purification, or green tree filtering, and for restoration of riparian woodlands. Trees were grown in pots with an inert mixture of perlite and vermiculite and irrigated with either nutrient solution or treated wastewater We measured the effects of species and irrigation water on biomass and nutrient content of leaves, stems and roots. For most of the species, treated wastewater had a positive effect on final biomass and above ground: below ground ratio compared to that of nutrient solution. However, growth of Cupressus sempervirens and Populus nigra were inhibited by water sodium concentration. Nerium oleander, Tamarix africana and Vitex agnus-castus were the species with the greatest final biomass. Pistacia terebinthus had the highest nitrogen and phosphorus content in leaves, stems and roots, while N. oleander and V. agnus-castus showed the best potassium accumulation. In general, P. terebinthus, N. oleander, T. africana and V. agnus-castus were the best qualified species for purification of wastewater.     

Environmental impact assessment in the Philippines: 1977–1985

During 1977 a Philippine environmental impact statement (EIS) system was established and the National Environmental Protection Council (NEPC) was formed to develop environmental policy. Several months after its creation, NEPC was given responsibility to certify that proposed projects met EIS system regulations. With few exceptions, this requirement to gain NEPC's approval was not taken seriously by agencies. The poor record of agency compliance with the EIS system is explained by the absence of ‘controls’ to force thorough assessments. Judicial controls are absent. Procedural and evaluative controls are in place, but NEPC has neither the budget nor the political power to enforce them. Although the national EIS system is ineffective, agencies sometimes conduct informal, ad hoc environmental assessments in response to instrumental controls exercised by international funding organizations, professional controls exerted by planners, and public controls brought about by individuals and groups who would be adversely affected by projects.