| 1 | Mercury removal using ground and calcined mussel shell显示文摘We determined mercury retention on calcined and ground mussel shell, in presence and absence of phosphate, using batch and stirred flow chamber experiments. In batch experiments the calcined shell exhibited higher Hg adsorption, with good fitting to Freundlich equation(R2: 0.925–0.978); the presence of phosphate increased Hg adsorption; mercury desorption was 13% or lower, diminishing up to 2% under the presence of phosphates. In stirred flow chamber experiments calcined shell retained more Hg than ground shells(6300 vs. 4000–5200 μmol/kg); Hg retention increased an additional 40% on calcined shell and up to an additional 70% on ground shells when phosphates were present; mercury desorption was quite similar in all shell types(20%–34%), increasing up to 49%–60% in ground shells when phosphates were present. The higher Hg adsorption on calcined shell would be related to its calcite and dolomite concentrations; mercury-phosphate interactions would cause the increase in Hg retention when phosphates are present. Data on Hg desorption suggest that Hg retention was not easily reversible after batch experiments, increasing in the stirred flow chamber due to convective flow. Calcined and ground mussel shells could be recycled removing Hg from water, with the presence of phosphates in solution improving efcacy. | Susana Pea-Rodríguez Alipio Bermúdez-Couso Juan Carlos Nóvoa-Muoz Manuel Arias-Estvez María J.Fernndez-Sanjurjo Esperanza lvarez-Rodríguez Avelino Núez-Delgado | 2013 | Journal of Environmental Sciences2013，25，12： | 3 |
| 5 | Abundance and harvest strategy of three species of clam (BivalviaVeneridae) located in new fishing banks in the Gulf of California显示文摘Clams of the family Veneridae in northwest Mexico have traditionally been exploited by small-scale fisheries.Despite their socioeconomic importance for coastal communities in the region,most catch zones are currently in decline due to a lack of harvest control regulations that would impede the depletion of local fishing banks.In Puerto Libertad,in the northern reaches of the Gulf of California,banks of commercially unexploited clam species,including Megapitaria aurantiaca,M.squalida and Dosinia ponderosa,were discovered.The adequate management and exploitation of these banks requires developing basic knowledge regarding the abundance of the species and establishing reference points to determine clear,simple harvest regulations.The goal of this study was to identify population abundance in these banks and ascertain the parameters of the life history of the species found there in order to propose a harvest strategy that will allow the sustainable exploitation of this resource.A total of 288 transects were conducted in the two clam banks to identify species density.Abundance was determined using a geostatistical method.The relative cohort biomass-at-length was estimated to evaluate the effect of different lengths of first capture on the remaining biomass.Based on these data,two harvest control regulations were proposed:a maximum catch(Cmax)of 10%of the total estimated biomass,and a minimum optimal catch size(Lc).The abundance estimates were M.squalida(266,293-381,881 individuals);D.ponderosa(2,779,100-3,455,597);and M.aurantiaca(408,783-447,391).The harvest control regulations proposed are:M.squalida,Cmax=2.98 t and Lc=50.33 mm;D.ponderosa,Cmax=49.67 t and Lc=103.44 mm;and M.aurantiaca,Cmax=15.87 t and Lc=80.85 mm.These results are important as reference information for implementing harvest strategies in clam-fishing banks,and as a contribution to the management and sustainable exploitation of fisheries in the region. | Jorge A.López-Rocha Francisco J.Fernández-Rivera Melo Ernesto Gastélum-Nava Estefani Larios-Castro | 2021 | Aquaculture and Fisheries2021，6，5： | 0 |
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