Interaction of Organisms in Abandoned Tin Mining Pits: Perspective of Life in Acid Mine Drainage Environment

Acid Mine Drainage (AMD) occurred after mining activity exposes metal sulfides to oxidizing conditions that impact acidic conditions with low pH values in the waters and heavy metals contamination. These conditions have also occurred in abandoned tin mining pits, one of places in Bangka Belitung Archipelago Province. This review aimed to elaborate information of micro-and macro-organism’ life in acid mi ne drainage to be associated with the possibility of life in abandoned tin mining pits. Acidophilic and acidotolerant organisms such as bacterial, phyto-and zooplankton, and some macroorganisms including invertebrate or vertebrate like fishes and also water plants were found in these waters. Their presence developed a symbiosis interaction in aquatic environment. Phytoplankton was an autotroph organism, despite being considered an autotroph organism, many phytoplankton require exogenous organic cofactors and nutrients for their life. These cofactors were often served by heterotroph bacterial to sustain the growth of phytoplankton. Instead, bacterial obtained dissolved organic matter derived from phytoplankton to survive in the aquatic environment. Furthermore, phytoplankton was consumed by zooplankton; zooplankton and/or insect on the water surface were consumed by surface feeder or small fish to big fish in the waters. In addition, water plants also support the interaction of organisms in the water by supplying dissolved oxygen, also anorganic and organic material for their life. The symbiosis and quorum sensing played an important role in structuring the aquatic food web and creating a life in the acidic water-polluted heavy metal in biogeochemical cycle. This review only focused on the role of bacterial in biogeochemical cycles in the acid mining environment. Research or review of other biogeochemical mechanisms was needed to reveal the entire biogeochemical cycles in acid mining waters.


Introduction
Nowadays, acid mine drainage (AMD) problem in abandoned mines have become a global environmental concern (Wang et al., 2021).Acid mine drainage is a waste from industry or activity of mining (Kaur et al., 2018).Abandoned mines and mine wastes are often acidic, sometimes extremely so and they often contain high concentrations of metals and possibly other heavy metals and also metalloids.This condition is also found on abandoned mining pits, include such as in Bangka Island and other producers of tin in the world.
Industrial waste and mining activities such as tin are one of the main sources of metal contamination (Guan et al., 2014;Kurniawan, 2016).Postactivity of tin mining produce metal contaminants such as Pb, Zn, Mn, Fe, Cr, Cu, Ni, and Cd as found in Heipang Nigeria (Daniel et al., 2014); Sn, Pb, Zn, Cr, Cu, and as in Bestari Jaya, Malaysia (Ashraf et al., 2011a;Ashraf et al. 2012a); and Fe, Pb, Cu, and Zn detected at tin mining sites in Bangka Island, Indonesia (Henny, 2011;Rosidah and Henny, 2012).
Other ecological changes can also be seen from the change in the acidity value (pH) of soil and water at the post-tin mining site.Characteristics of relatively acidic to neutral pH values (4.8-7.2) (Ashraf et al., 2013) and can be even lower than pH 4 as well as nutritional deficiencies and low dissolved oxygen values (Kurniawan, 2016).Tin mining activity in soil ecosystems leads to low ion exchange capacity, organic matter, total nitrogen, phosphorus availability, macro nutrients, and clay soil content (Oktavia et al., 2014).Mining activities cause ecological imbalances and damage, including physical, chemical, and biological changes within macro-and microecosystems (Fan et al., 2002;Vyas and Pancholi, 2009;Ashraf et al., 2010;Ahmad, 2013;Singh et al., 2013;Giri et al., 2014;Lad and Samant, 2015).
Therefore, the main objective of this review is to summarize the scientific literature related to AMD water, especially abandoned tin mining pits and its effects on organisms thriving in the heavy metalcontaminated and acidic water, their metabolism in the habitat, and their interactions on biogeochemical mechanism that support their life and succession in the environment.This review focused to role of bacterial in biogeochemical cycle in the acidic water of abandoned tin mining pits.

Perspective of Life in Acid Mine Drainage Environment A. Acid Mine Drainage
Acid mine drainage (AMD) forms when sulfide minerals are exposed to oxidizing condition during metal mining, highway construction, and other largescale excavations (Skuosen et al., 2000).The formation of AMD is a sequence of complex biogeochemical and mineral dissolution processes (Dold, 2014), characterized by acidic effluents with a high content of sulfide mineral and heavy metal ions in water (Pozo-Antonio et al. 2014).A number of sulfide minerals found in the waters acids are categorized as Potentially Acid Forming (PAF) or materials that can cause the formation of acidic pH conditions in the environment such as pyrite (FeS2), chalcopyrite (CuFeS2), galena (PbS), sphalerite ((Zn,Fe)S) (Celebi and Oncel, 2016).These minerals undergo oxidation to produce the final product in the form of H + ions (Gonzalez-Toril et al., 2006;Mejia et al., 2009;Heidel and Tichomirowa, 2011;Dopson and Johnson, 2012).
Many researches have shown that the exposed pyrite in metal mining is the main cause of acid mine drainage.When pyrite reacts with oxygen and water, the products are Fe ions and sulfuric acid.
The general chemical reaction that describes the oxidation of pyrite and the formation of acid is given by the following equation.There are four generally accepted chemical reactions that represent the weathering chemistry of pyrite that forms AMD.Here is an overview of the overall reactions (Gaikwad and Gupta, 2007;Byrne et al. 2012): 4FeS2 + 15O2 + 14H2O → 4Fe(OH)3↓ + 8H2SO4 (1) Pyrite + Oxygen + Water → "Yellowboy" + Sulfuric Acid The first reaction in pyrite weathering involves the oxidation of pyrite by oxygen.Sulfur is oxidized to sulfate and iron is released.This reaction produces two moles of acidity per mole of pyrite oxidized.2FeS2 + 7O2 + 2H2O → 2Fe 2+ + 4SO4 2-+ 4H + (2) (pyrite oxidation process) Pyrite + Oxygen + Water → Ferrous Iron + Sulfate +

Acidity
The second reaction involves the conversion of ferrous iron to ferric iron.To convert ferrous iron (Fe(II)) to Ferric iron (Fe(III)) need one mol of acidity.Certain bacterial increase the rate of iron (II) oxidation to iron (III).This reaction rate is pH dependent, and the reaction proceeds slowly under acidic conditions (pH 2-3) in the absence of bacterial, and is several orders of magnitude faster at pH values close to 5.This reaction is called "velocity".The "restriction steps" for overall acid production indicate the order.4Fe 2+ + O2 + 4H + → 4Fe 3+ + 2H2O (3) (ferrous iron oxidation process) Ferrous Iron + Oxygen + Acidity → Ferric Iron + Water The third possible reaction is the hydrolysis of iron.Hydrolysis is a reaction that breaks down water molecules.As a by-product, three moles of acidity are produced.Many metals can be hydrolyzed.The formation of ferric hydroxide precipitates (solids) depends on pH.When the pH is above about 3.5, solids are formed, but below pH 3.5, the solids hardly or at all precipitate.
4Fe 3+ + 12H2O → 4Fe(OH)3 ↓ + 12H + (4) (ferric iron hydrolisis process) Ferric Iron + Water → Ferric Hydroxide (yellow boy) + Acidity The fourth reaction is the oxidation of additional pyrite by ferric iron.Iron (III) is produced in reactions steps 1 and 2. This is a periodic, self-propagating part of the entire reaction that occurs very quickly and continues until either ferric or pyrite is exhausted.Note that in this reaction, iron is an oxidizer, not oxygen.
2FeS2 + 14Fe 3+ + 8H2O → 15Fe 2+ + 2SO4 2-+ 16H + (5) (ferric iron oxidation process) Pyrite + Ferric Iron + Water → Ferrous Iron + Sulfate + Acidity Equation describes about producing ferric iron as the primary oxidant of pyrite.Under abiotic conditions the rate of oxidation of pyrite by ferric iron is controlled by the rate of oxidation of ferrous iron, which decreases rapidly with decreasing pH.Below about pH 3, the oxidation of pyrite by ferric iron is about ten to a hundred times faster than by oxygen (Dold, 2014).
Oxidation and hydrolysis reactions that occur to elements such as S, Fe, Cu, Zn, Ni, Cr, Pb, into cations such as Cu 2+ , Zn 2+ , Ni 2+ , Cr 3+ , Pb 2+ , and other elements in the mining environment cause an increase in the number of H + protons that are produced, contribute to an increase in environmental acidity conditions.The more H + ions in an environment, the more acidic the pH conditions in the environment (Gaikwad and Gupta, 2007;Hatar et al., 2013).The increase in the value of H + also occurs in organic and inorganic materials such as ammonia and carbon dioxide.The acidity caused by the ammonium nitrification process takes place through the reaction of NH4 + + 2O2 → NO3 - + 2H + + H2O and then dissolved nitrate (NO3 -) (Goulding, 2016).The chemical interaction between carbon dioxide and water produces a weak acid through the reaction of CO2 + H2O → H2CO3 and then carbonate ions (HCO3 -) and protons (H + ) are formed (Stallinga, 2018).
The increase of H + ions is responsible for lowering the pH and degrading the quality of the water and disturbing the aquatic organism's life.Increased acidity has a particularly harmful effect on organisms from their early life stages such as fish larvae, impact in their respiration and oxygen consumption, depressing effect on the growth rate and survival rate (Srineetha et al., 2014;Ndubuisi et al., 2015) and also disturb on photosynthesis of water plants (Long et al., 2017).However, some organisms "extremophiles" can thrive under multiple extremes conditions (Merino et al., 2019).

B. Abandoned Tin Mining Pit in Bangka Belitung Archipelago Province
The existence of former mining pit-like a lake, particularly tin mining in Bangka Belitung Archipelago Province, Indonesia (in local language called kolong) presents a significant impact from abandoned mining activities (Kurniawan et al., 2020).Abandoned tin mining pits become a new ecological model for studying of biological life, metabolism, and organisms' interaction in this habitat, especially tin producers in the world such as Indonesia, Malaysia, and others.Some studies result information about this environment such as water quality (Ashraf et al. 2012b;Hashim et al., 2018), heavy metal contamination (Ashraf et al., 2011a;Ashraf et al., 2011b;Ashraf et al. 2012a;Kurniawan, 2020), microorganism and molecular diversity (Sow et al., 2014a(Sow et al., , 2014b)), and also extremophile fishes (Kurniawan et al., 2020;Kurniawan and Mustikasari, 2021).The morphological view of some abandoned pits in Bangka Island of Indonesia were shown in Figure 1.Tin mining activities carried out on land in Bangka Belitung Island have led to the formation of pits by a spray mining method.This process is carried out through the stripping stage in the form of dismantling soil layers to a certain depth, spraying stages to disassemble or dissolve soil or rocks containing tin seeds so that they turn into mud, and washing stages to separate lead seeds from other materials through the deposition process (Harahap, 2016).Tin mining activitiy does not use chemicals, but elements or minerals such as Fe, Sn, Pb, Cu, and so on in nature can undergo oxidation and other chemical reactions that cause changes in water quality and potential heavy metal pollutant residues (Kurniawan et al., 2019;Kurniawan and Mustikasari, 2019).The authors have found in the before research some elements, bacterials, and fishes in abandoned tin mining pits, resumed in Table 1.
Tin mining activity doesn't use chemical materials during the exploration process, but the effect of mining activity is the elements contained in nature can undergo oxidation and chemical reactions.The consequence of pyrite and other sulfide oxidation can cause severe acidification of mine water, accelerate erosion of basins, promote heavy metal migration and threaten local ecosystems such as aquatic life and human health (Li et al., 2018).Authors observe onshore mining activity impact to ecological changes such as deforestation, biodiversity recuding, water flow damages, decrease of environmental stability, also macro-and microorganism structure alteration.Furthermore, for a long chronosequence, it may drive the changes of organisms' metabolism to survive in the environment.

C. Organisms in Acid Mine Drainage-Polluted Heavy Metals
Acid mine drainage (AMD) is a highly acidic wastewater rich in heavy metals and metalloids (Plaza-Cazón et al., 2021).In this condition, only selected organisms can survive and life normally.Known as extremophiles, these organisms breed in habitats that are intolerably hostile or even deadly to other terrestrials.One of them thrive in acidic conditions and some can grow in toxic waste, low nutrient content, and also heavy metals pollution.Extremophiles can be broadly divided into two categories; extremophilic organisms that require one or more extreme conditions to grow optimally and extremotolerant organisms which can tolerate extreme values of one or more physicochemical parameters (Rampelotto, 2013).The organisms may be described as acidophilic (optimal growth between pH 1 and pH 5), oligotrophic (growth in nutritionally limited condition), and metallophiles/ metallotolerants (resistant to high concentration of metals).
However, in this review, we only deal with extremophile organisms related with acidic waterpolluted heavy metal as well as abandoned tin mining pits conditions, which can categorized as polyextremophiles due to these extremophiles are adapted simultaneously to multiple stresses, as an acidophilic and metallophilic or metallotolerant.
Environmental pH values are an important factor in acidophiles identification so they are grouped into two, namely true or extreme acidophiles and moderate acidophiles.True acidophiles (extreme acidophiles) can live at a pH of 2.7 and even some can live at a pH < 1.0 with an optimum pH of growth of < 3.0.Moderate acidophiles are able to live in the wider pH range, which is 3.0-7.2with an optimum pH of growth of 3.0-5.0(Johnson and Hallberg, 2008;Mendez et al., 2008;Oren, 2010).The acidophilic group has a fairly wide growth range, but optimum growth takes place between a pH of 1.0 and a pH of 5.0.This characteristic distinguishes from other groups such as neutrophiles that live tolerant in the pH range of 5.0-9.0 with the optimum pH for growth being 7.0 as well as alkaliphilic tolerant live at pH 6.0-12.0 with optimum pH above 9.0 or often between pH 10.0 and pH 12.0 (Gupta et al., 2014;Horikoshi, 2016).
In addition, in this review we use term acidotolerant to desctribe organisms which can live in acidic condition, while metallotolerant to describe organisms which can survive in environmentcontaminated heavy metals, especially in abandoned tin mining pit.We tend to agree with Maltman and Yurkov (2019) that explained organisms that can withstand high concentrations of metals (metalloids) are called metallophile.However, this description can be a bit misleading.The suffix "phile" means that it is highly compatible in the presence of metals (metalloids).This is because even highly resistant microorganisms do not always grow well at such high levels and also it does not require oxyanions to survive.Therefore, term of metallophile/metallophilic is not used in this review and a more appropriate term is metallotolerant.
In this review, authors do references approach to elaborate some acidophilic and metallotolerant organisms found in other mining site or extreme environment to reveal potential of these organisms existing, which might be found in abandoned tin mining pits.In this perspective, we highlight acidophile-metallotolerant as our term to disclose these organisms.Furthermore, it will becomes information as a guide for researching the presence of these organisms in this water.Some researchers has discovered the ability of some organisms to survive in extreme conditions of acidic and heavy metal contamination where some of them are resumed in Table 2.
All of them develop self-abality to survive so they can play an important role in this environment.Metallotolerant microorganism as well as acidophile have been found to be capable of efficiently accumulating heavy by the mechanisms of acidolysis, transport across cell membrane, complexation, ion exchange, precipitation, physical adsorption, accumulation, chelate, redoxolysis, and leaching which are carried out through physical mechanism, chemical modification or by influencing chemical bioavailability (Rao et al., 2002;Siswati et al., 2009;Damodaran et al. 2011;Harms et al., 2011, Javanbakht et al., 2014;Chaturvedi et al., 2015;Dixit et al., 2015;Dusengemungu et al., 2021).
In principle, acidophile, acidotolerant, and metallotolerant which do acidolysis, they can exchange metal oxide and decrease H + ion by metal oxide detachment and react oxygen with water, as shown in the reaction MeO + 2H + → Me 2+ + H2O.Protons attach and react to the metal and then reduce the strength of chemical bonds so metal ions are removed from the metal surface (Srichandan et al., 2019).Furthermore, Me 2+ as a metal cation will be processed as well as microbe capability such as accumulate or precipitate the cation ion become solid, as exampled in this reaction Me 2+ + HO2C.CO2H → (Me(O2C.CO2)(s) + 6H + and Me 2+ + SO4 2− → MeSO4(s) (Dusengemungu et al., 2021).In addition, they can play oxidation and reduction reactions to use the metal as their nutrition or detoxification of the metal to make sure their environment.For example, they are capable of both reactions, that reduction, and oxidation such as reduce Fe 3+ with H2 as an electron donor or oxidize Fe 2+ with NO3 -as an electron acceptor (Zhang et al., 2009).Some of aquatic plants do their role as phytoremediator with mechanisms such as phytoextraction, rhizofiltration, phytovolatilization, and phytostabilization during the process of uptaking or accumulating of heavy metals from the environment (Ali et al., 2020).Phytoextraction (phytoaccumulation) refers to the uptake and translocation of metal in the environment by plant roots to above-ground plant parts.The plants can harvest and burn metals for energy, and the pollutants can be recovered/recycled from the ashes as needed by phytoextraction process (Erakhrumen, 2017;Chandra et al., 2018;Sukono et al., 2020).Roots play a very important role for rhizofiltration to absorb or adsorb the pollution, resulting in restricted movement of these contaminants in the environment (Abhilash et al., 2009;Benavides et al. 2018;Sukono et al., 2020).Phytovolatilization is the process in which a plant converts pollutants into a different volatile nature and then transfer them into the atmosphere by the plant' stomata (Ghosh and Singh, 2005;Leguizamo et al. 2017;Sukono et al., 2020).Phytostabilization also known as in place deactivation, using plants to reduce heavy metal bioavailability and to restrict the movement of contaminants in the environment (Abhilash et al., 2009;Benavides et al., 2018;Yan et al., 2020).

D. Life in Acidic-Heavy Metals Water: Perspective of Tin Mining Pit
Interactions of organisms play a critical role in existence and prospects of life in acid-heavy metals waters as formed as acid mine drainage.In addition, we elaborated many papers to construct a life in a perspective of tin mining pit based on life approach in the acid mine drainage.Hui (2012) explained the food chain is an important for ecological concept, especially in a life concept, organisms' interaction, nutritional relationships, and energy flow or transfer, which begins with autotrophs (known as the grazing food chain) and which begins with dead organic matter (known as the harmful food chain).Meanwhile, through this theory, we present a concept of thought about a food chain scheme that might occured in a tin mining pit (Figure 2).The food chain of this habitat offers important informations for studies of the ecological interactions that define energy flows and the relationship of producer and consumer in an ecosystem, directly impact to nutrient cycling and biological life.
An essential part of a food chain is that each organism or their group are of equal importance to the ecosystem and play important role in an environment.We focused to constructed role of some microbes of abandoned tin mining pit, especially phylum of bacterial which affect to its characteristics and ecological exchange in a biogeochemical process (Figure 3).
Bacterial is a group of microorganisms have the highest ability of all life forms to adapt to extreme and stressful environments due to the ability to transfer genetic information as a major factor in adaptation to environment changes.The population genetic diversity also contribut as one of the major factors determining the adaptation ability of a species to environmental variations (Jump et al. 2009).Bacterial, part of microbes can do their activity absolutely in aerobic and anaerobic conditions or facultative between aerob or anaerob conditions depending on the environment they are in.
Furthermore, some of them can do photosynthesis process.The photosynthetic bacterial used sun' light to produce energy in a process similar with plants.Instead of using the chlorophyll, they use bacteriochlorophyll compounds to capture the sun' light and do the photosynthesis (Emmyrafedziawati and Mohd Aziz, 2016).
The aerobic phototrophic bacterial are a recently discovered group capable of producing a photosynthetic apparatus like the purple phototrophic bacterial.These bacterial have bacteriochlorophyll (BChl) a incorporated into light harvesting (LH) and reaction center (RC) complexe capable of transforming light into electrochemical energy under aerobic conditions (Rathgeber et al., 2004).To date, thera are six bacterial phyla namely Cyanobacteria, Proteobacteria, Chlorobi, Chloroflexi, Firmicutes, and Acidobacteria that using (bacterio)chlorophyll-based photosynthetic reaction centers (chlorophototrophs) (Zeng et al. 2014).There are four known phylogenetic groups of anoxygenic phototrophs: the green sulfur bacterial, the green non-sulfur bacterial, the heliobacteria, and the purple bacterial which consist of purple sulphur and purple non-sulphur bacterial (Emmyrafedziawati and Mohd Aziz, 2016).These microorganisms use reduced sulfur (S) compounds as electron donors in the process of anoxygenic photosynthesis (Kushkevych et al., 2021).Kurniawan (2020) has explained the phyla of bacterial found in acid mine drainage, especially abandoned tin mining pits.We assumed that occurred the biogeochemical process in this habitat that involved bacterial so cause characteristic changes in this environment (Figure 3).
The oxidation of sulfide minerals and heavy metals found in abandoned tin mining water make acidic condition in the water.Biologically, Acidophile bacterial such as Actinobacteria, Firmicute, and Chloroflexi oxidized sulfide minerals and heavy metals so accelerate acidic forms in abandoned tin mining pit and increase ion H + that cause acid condition in this water.While, the physically and chemically oxidation process also occurs to sulfide minerals and heavy metals (Bao et al., 2022) so cause pit water has acidic characteristic.
Chronosequently, within a certain time, organic matter from bacterial, archaea, microfungi, planktonic organisms were degradated and composed in this water.For quite of while, the organic matters and the degradating or composting product of organic matters were accumulated and caused increasing of c-organic.This organic material and its products were used Bacteroidetes as an energy source for their life and biochemical activity, include to decompost organic matters.Bacteroidetes play important role in decomposition process as a key of carbon cycle in an environment (Herzog et al., 2019).
We analyzed that the presence of organic material implicates to two major mechanisms: (1) carboxylix bond (COOH -) of organic matters bound H + ions of sulfide minerals and heavy metals and (2) CO2 and H2O as decomposition products can be reacted to produce H2CO3, while bicarbonate ion (HCO3 -) also bound H + ions of sulfide minerals and heavy metals.These mechanisms caused H + ions in abandoned tin mining water will be decreased and the implication was increasing pH value, changes from acid to be a neutral or base.Vijayakumar et al. (2019) explained that a solution with a high concentration of hydrogen ions have a low pH (acid) and solution with low concentrations of H+ ions have a high pH concentration (neutral to base).
The pH changes contributed to ability of the other bacterials to life in this habitat such as Cyanobacteria, Proteobacteria, and Planctomycetes.The presence of Cyanobacteria as a primary producer contributes to photosynthesis by fixation of inorganic carbon (CO2) to organic carbon ((CH2O)n) and releasing oxygen (Prieto-Barajas et al., 2018).Thereby, dissolved oxygen in this habitat will be increase and impact to other organisme, involved bacterial (e.g Proteobacteria and Planctomycetes), plankton, water plants, and fishes.
In addition, degradation organic matter produced ammonia (NH3) that can be used by group of ammonia oxidizing bacterial (AOB), nitrit oxidizing bacterial (NOB), anaerobic ammoniua oxidation, and complete ammonia oxidation (commamox) to produced nitrogen.Guignard et al., (2017) explained the presence of nitrogen impact to increasing of plant and animal abundances; trophic interactions and population dynamics; and ecosystem dynamics and productivity.
Therefore, the presence of bacterials and they work together, called quorum sensing (Kurniawan and Asriani, 2020) can create a habitable zone for many waters organisms, from micro to macroorganisms and revive the food or web chains in the environment, include abandoned tin mining water.

Conclusion
We have disclosed about the interaction of organisms in abandoned tin mining pits by the perspective of life in acid mine drainage environment.We believed some bacterial of abandoned tin mining water as part of acid mine drainage played important role in biogeochemical process to change water quality and create a food or web chains by a creating habitable environment for all organisms, including micro-to macroorganisms.Some groups of bacterial played important role in organic matter cycle and another played in anorganic cycle of biogeochemical mechanisms.This review was only limited to reveal the role of bacterial in abandoned acid mining waters.Further researches were needed to explain about the food chain and energy transfer that occurs in these waters.

Figure 2 Figure 3
Figure 2 Food chain and energy flow in a pit environment