To remediate or to not remediate?
Pollution of coastal areas in marine and freshwater ecosystems is a direct consequence of the anthropogenic pressure on these areas. In addition, pollutants that are originated afar do enter aquatic ecosystems through a variety of processes, including atmospheric deposition and continental run-off. In aquatic environment, the sediment (i.e. the particle matter that covers seafloors, riverbeds and lake bottoms) is the final repository for contaminants, where they accumulate and reach concentrations that are much higher than in the water column. The proper management of contaminated aquatic sediments is a modern day issue of significant concern. Because of a variety of maintenance activities in commercial ports and other aquatic areas affected by industrial activities, thousands of tonnes of contaminated sediment are dredged worldwide per year. Integrative approaches are needed and strategies should include an accurate analysis of the possible environmental consequences.
In the search of viable alternatives to the high costs and impacts of conventional strategies, bioleaching has been often proposed as promising biotechnology for reclaiming dredged materials that are contaminated by metals. Through bioleaching approach, Fe/S oxidizing bacteria are exploited to solubilize metal contaminants and remove them from the sediment. Once decontaminated, the material could well suit the building industry, or could be used for beach nourishment.
Our work at Universita` Politecnica delle Marche has addressed the use of bioleaching techniques for the decontamination of dredged sediments, in view of their potential re-use. Our studies have highlighted that, although it can be successfully applied to remediate to metal contamination in dredged materials, bioleaching could not be the most suited approach. Sediments, especially the marine ones, are often characterized by high buffering capacity, which in field applications would results in the need of high volumes of acids, high consumes of water and CO2 emissions. The content of carbonates and aged organic matter are the main responsible for these problems. Then, sediment characteristics result to be a factor of primary relevance in the choice of bioleaching techniques as sediment cleanup tool. Dredged materials with high amount of carbonates and organic matter and middle-low contamination levels should be treated by alternative approaches, like phytoremediation, or be managed by conventional strategies, including capping.
Research efforts in the last four decades have generated a significant breakthrough in human understanding of environmental processes and on the consequence of human activities on the environment. There are several examples of environmental remediation actions that have successfully reclaimed polluted sites. However, there are also examples of remediation actions that have failed in their purposes and, not infrequently, have generated high environmental impacts for low-level environmental risk, generated hazardous by-products or increased exposure risk.
On the light of the knowledge that humans have gained, environmental remediation is not always the answer to environmental issues. Modern society should invest much more efforts in reducing pollution and environmental degradation instead of tempting to remediate after the die is cast.
Viviana Fonti
Dipartment of Life and Environmental Sciences (DISVA), Università Politecnica delle Marche,
via Brecce Bianche, Ancona, Italy
Publication
Does bioleaching represent a biotechnological strategy for remediation of contaminated sediments?
Fonti V, Dell’Anno A, Beolchini F
Sci Total Environ. 2016 Sep 1
Related Articles:
 | Ferrate technology: an innovative solution for… Sewers might be out of sight, but they play a huge role in shaping the well-being of a society. They quietly carry away all the wastewater from our homes, businesses,… |
 | Murburn concept explains why oxygen is acutely… Murburn concept (from “mured burning”, signifying a restricted uncontrolled oxidative process) provides a tangible rationale why oxygen is so quintessential for immediate maintenance of life-order. It postulates that oxygen-centered diffusible… |
 | Microbial community assembly and the microbiome revolution Microbial communities (i.e. groups of potentially interacting microbial populations that co-exist in space and time) most commonly represent complex and highly diverse assortments of microbial populations, each possessing different genomic… |
 | Campylobacter antimicrobial resistance in dogs and humans Campylobacteriosis has been the most frequently reported zoonotic disease in humans in Europe since 2005, and the annual number of notified campylobacteriosis cases has increased in many European countries in… |
 | Sustainable solutions: Tamarind Seed Kernel powder… The majority of petroleum-based adhesives applied in the wood industry today, particularly formaldehyde-based adhesives. Their application trend is increasing due to their wide availability, superior bonding, durability, and resistance to… |
 | Boosting chicken health with tea extract: a natural… In modern poultry farming, chickens often face stressful conditions such as overcrowding, poor air quality, and contaminated feed. These conditions can lead to oxidative stress, a state where an excess… |
Leave a Reply
You must be logged in to post a comment.