Department of Biotechnology, Goa University, Taleigao Plateau, Goa, India.
Environ Monit Assess. 2013 May;185(5):3625-36. doi: 10.1007/s10661-012-2814-7. Epub 2012 Aug 16.
The Ribandar solar saltern, situated adjacent to the Mandovi estuary is influenced by the barge transport of ferromanganese ore to the Mormugao harbour (Arabian Sea). The current study focuses on the distribution of metals and related heterotrophic bacterial populations in the surface sediments (0-10 cm) of the Ribandar salterns (Goa, India) during the salt-making (January to May) and non salt-making seasons (August and November). The concentrations of heavy metals in the sediments ranged from 17.2 ± 2.8 to 26.3 ± 6.7 % Fe; 0.6 ± 0.2 to 0.9 ± 0.2 % Mn; 27.6 ± 7.3 to 51 ± 8.3 ppm Ni; 28.4 ± 8.9 to 35.2 ± 10.6 ppm Co; 44 ± 21.6 to 62.8 ± 23.6 ppm Zn; 0.1 ± 0.01 ppm Cd and 1.7 ± 0.1 to 2.6 ± 0.7 ppm Pb and were much higher than those reported at the same site in a previous study by Kerkar (2004). Hg concentrations were below detection limits. In general, computation of "geoaccumulation index" revealed the sediments as 'uncontaminated to moderately contaminated' with Fe, Mn, Ni, Co, Pb and Zn during the salt-making season. The abundance of metal-tolerant bacteria was comparatively restricted to the salt-making season and was higher than the non salt-making season. Fe-, Mn-, Ni-, Co- and Pb- (200 ppm) tolerant bacteria were retrieved and restricted to the surface sediments (0-5 cm), Cd and Fe being the two most regulatory elements governing bacterial populations in the non salt-making season. However, during the salt-making season, the concentration of Zn was found to be pivotal in regulating the counts of Fe-, Mn- and Ni-tolerant bacteria. In general, the strength of correlation of metals and microbes was higher in the non salt-making season as compared to the salt-making season. This would probably indicate metal-induced limitations in microbial populations in the non salt-making season and the absence of this effect during the salt-making season. In this study, we test the hypothesis that solar salterns behave as ecological sinks with a potential to transform native bacterial populations to metal-resistant strains, in relation to the dynamic changes in the surrounding metal concentrations.
里班达尔太阳能盐场位于芒多维河口附近，受到驳船运输铁锰矿石到 Mormugao 港（阿拉伯海）的影响。本研究重点关注里班达尔盐场（印度果阿邦）在制盐（1 月至 5 月）和非制盐季节（8 月和 11 月）期间表层沉积物（0-10cm）中金属和相关异养细菌种群的分布。沉积物中重金属的浓度范围为 17.2±2.8%至 26.3±6.7%的 Fe；0.6±0.2%至 0.9±0.2%的 Mn；27.6±7.3ppm 至 51±8.3ppm 的 Ni；28.4±8.9ppm 至 35.2±10.6ppm 的 Co；44±21.6ppm 至 62.8±23.6ppm 的 Zn；0.1±0.01ppm 的 Cd 和 1.7±0.1ppm 至 2.6±0.7ppm 的 Pb，均远高于 Kerkar（2004 年）在同一地点进行的先前研究报告的水平。Hg 浓度低于检测限。总体而言，“地质累积指数”的计算表明，在制盐季节，沉积物为“无污染到中度污染”，Fe、Mn、Ni、Co、Pb 和 Zn 含量较高。金属耐受细菌的丰度在制盐季节相对受限，高于非制盐季节。从盐场中分离出并仅限于表层沉积物（0-5cm）的耐受 200ppm 的 Fe、Mn、Ni、Co 和 Pb 的细菌，Cd 和 Fe 是控制非制盐季节细菌种群的两个最重要的调节元素。然而，在制盐季节，发现 Zn 浓度在调节 Fe、Mn 和 Ni 耐受细菌的数量方面起着关键作用。一般来说，与制盐季节相比，非制盐季节金属和微生物之间的相关性更强。这可能表明非制盐季节金属对微生物种群的限制作用，而在制盐季节则不存在这种影响。在这项研究中，我们检验了这样一个假设，即太阳能盐场作为生态汇，具有将原生细菌种群转化为金属抗性菌株的潜力，这与周围金属浓度的动态变化有关。
