Contaminated land in Colombia: A critical review of current status and future approach for the management of contaminated sites

Developing an institutional control framework for contaminated sites in China: An analytical case study

Institutional controls, as an important measure for risk management of contaminated sites, is widely used in site management by the United States, Canada and European countries. At present, some regions in China have also begun to explore the implementation of institutional controls, but its path, safeguard mechanism, and tracking evaluation are still unclear. Based on China's unique contaminated site remediation control system and land management system, this paper proposes a framework for the whole life cycle institutional controls of China's contaminated sites: (1) evaluate the need for institutional controls; (2) establish the objectives of institutional controls; (3) identify the restrictive requirements of institutional controls; (4) establish the implementation form of institutional controls; and (5) regularly review the effectiveness of institutional controls. To demonstrate the applicability of the institutional control framework, a case demonstration study was conducted at a petrochemical contaminated site in China. By analyzing the information on residual pollutants after the implementation of risk management measures at the site, the exposure pathways and hazards in case of re-release, and the engineering facilities, we proposed eight restrictive requirements, including the prohibition of disturbing and damaging the clean and planted soil layers of the site and the protection of long-term monitoring wells. At the same time, we constructed a multi-departmental pathway to implement institutional controls in conjunction with ecological environment, natural resources and housing departments to ensure effective implementation of institutional controls. Eventually, we summarized a set of replicable and generalizable institutional controls application models, which provide valuable theoretical and practical support for China and other local governments in the implementation of institutional controls at contaminated sites.

Unravelling arsenic bioavailability in floodplain soils impacted by mining activities

Gold mining not only introduces mercury (Hg) contamination to soils but also facilitates the mobilization of other toxic substances, including arsenic (As). This study assessed the total content, chemical species, and bioavailable fraction of As in surface soils impacted by mining residues during frequent flooding. Analysis of 207 soil samples across the floodplain region of La Mojana, Colombia, screened to 2 mm with polyethylene mesh, revealed significant correlations (p < 0.05) between inorganic As, the residual phase, sulphur (S), iron (Fe), manganese (Mn), and aluminum (Al), indicating associations with sulfides and oxyhydroxides of Fe and Mn. The origin of toxicity was linked to suspended materials transported by rivers during flooding in areas with intense mining activity. Sites with better oxidizing conditions exhibited a higher presence of phases associated with amorphous and crystalline oxides in non-flooded areas. Although the bioavailable fraction was minimal in flooded sites, reducing conditions facilitated As mobility, resulting in higher concentrations in deeper soil layers, particularly as As(III). The contamination factor (CF) ranged from 1.3 to 11.1, and the geochemical index (Igeo) ranged from -0.2 to 2.9, indicating a moderate to high As contamination level in soils. This poses potential health risks, considering the agricultural use of these soils.

Occurrence and toxicological relevance of pesticides and trace metals in agricultural soils, sediments, and water of the Sogamoso River basin, Colombia

Historical pesticide use in agriculture and trace metal accumulation have long term impact on soil, sediment, and water quality. This research quantifies legacy and current-use pesticides and trace metals, assessing their occurrence and toxicological implications on a watershed scale in the Sogamoso River basin, tributary of the Magdalena River in Colombia. Organochlorine pesticides (22), organophosphates (7), and azole fungicides (5), as well as trace metals cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn) were analyzed in croplands and along the river. Toxic units (TU) and hazard quotients (HQ) were calculated to assess the mixture toxicity. Organochlorines were detected in 84% of soils, 100% of sediments, and 80% of water samples. Organophosphates were found in 100% of soil and sediment samples, as well as in 70% of water samples. Azole fungicides were present in 79% of soils, 60% of sediments, and in 10% of water samples. Total pesticide concentrations ranged from 214.2 to 8497.7 μg/kg in soils, 569.6-12768.2 μg/kg in sediments, and 0.2-4.1 μg/L in water. In addition, the use of partition coefficient (Kd) and organic carbon fraction (foc) allowed the distribution analysis for most of the pesticides in sediments, suspended particulate matter (SPM), and water systems, but not for soils. Concentrations of trace metals Cu, Zn, Pb, and Zn exceeded international quality guidelines for agricultural soils in 16% of the samples. Furthermore, Cu and Zn concentrations exceeded sediment quality guidelines in 50 and 90% of the samples, respectively. These findings demonstrate the broad distribution of complex mixtures of trace metals, legacy organochlorines, and current-use pesticides across the basin, indicating that conventional agriculture is a significant source of diffuse pollution. Sustainable agricultural practices are needed to mitigate adverse impacts on ecosystems and human health.

Assessing the cadmium content of cacao crops in Arauca, Colombia

The district of Arauca is the second-largest producer of cacao in Colombia. However, despite its quality, it faces issues for export due to levels of cadmium (Cd) higher than the regulatory thresholds. A central question is how it may impact agricultural performance in the presence of Cd in cacao and chocolates. This study quantified Cd in cacao plantations from Arauca. Thus, 180 farms were assessed in the municipalities of Arauquita, Fortul, Saravena, and Tame. Five sample types (soil, irrigation channel sediment, soil litter, cacao seeds, and chocolates) were assessed for Cd. As a technological innovation, the new MXRF technology was used for Cd in chocolates. The sequence of Cd content was soil litter > chocolate > soils > cacao seeds > irrigation-channel sediment. A gradient north-south of Cd content in soil was observed, where highest content was found in farms near the Arauca River, and lower farther away. In irrigation channel sediment, Cd levels averaged 0.07 mg kg-1. The Cd content in cacao seeds was 0.78 mg kg-1 on average. Cd content in chocolates was above the threshold (1.10 mg kg-1 on average, including several cacao mass percentages). These artisanal chocolate bars produced by single farms were near the limit of Cd set by the European Union (up to 0.8 mg kg-1). Therefore, mixing beans from different farms could reduce their Cd content. The present study underscores the complexity of Cd distribution, emphasizing the importance of integrating soil, crop, and landscape features in managing and mitigating Cd levels in cacao.

Responses of microbial communities subjected to hydrodynamically induced disturbances in an organic contaminated site

Organic contaminated sites have gained significant attention as a prominent contributor to shallow groundwater contamination. However, limited knowledge exists regarding the impact of hydrodynamic effects on microbially mediated contaminant degradation at such sites. In this study, we investigated the distribution characteristics and community structure of prokaryotic microorganisms at the selected site during both wet and dry seasons, with a particular focus on their environmental adaptations. The results revealed significant seasonal variations (P < 0.05) in the α-diversity of prokaryotes within groundwater. The dry season showed more exclusive OTUs than the wet season. The response of prokaryotic metabolism to organic pollution pressure in different seasons was explored by PICRUSt2, and enzymes associated with the degradation of organic pollutants were identified based on the predicted functions. The results showed that hormesis was considered as an adaptive response of microbial communities under pollution stress. In addition, structural equation models demonstrated that groundwater level fluctuations can, directly and indirectly, affect the abundance and diversity of prokaryotes through other factors such as oxidation reduction potential (ORP), dissolved oxygen (DO), and naphthalene (Nap). Overall, our findings imply that the taxonomic composition and functional properties of prokaryotes in groundwater in organic contaminated sites is influenced by the interaction between seasonal variations and characteristics of organic pollution. The results provide new insights into microbiological processes in groundwater systems in organic contaminated sites.

Vertical and seasonal dynamics of bacterial pathogenic communities at an aged organic contaminated site: Insights into microbial diversity, composition, interactions, and assembly processes

Under the background of the Coronavirus Disease 2019 (COVID-19) pandemic, research on pathogens deserves greater attention in the natural environment, especially in the widely distributed contaminated sites with complicated and severe organic pollution. In this study, the community composition and assembly of soil pathogens identified by the newly-developed 16S-based pipeline of multiple bacterial pathogen detection (MBPD) have been investigated on spatiotemporal scales in the selected organic polluted site. We demonstrated that the richness and diversity of the pathogenic communities were primarily controlled by soil depth, while the structure and composition of pathogenic communities varied pronouncedly with seasonal changes, which were driven by the alterations in both physiochemical parameters and organic contaminants over time. Network analysis revealed that the overwhelmingly positive interactions, identified multiple keystone species, and a well-organized modular structure maintained the stability and functionality of the pathogenic communities under environmental pressures. Additionally, the null-model analysis showed that deterministic processes dominated the pathogenic community assembly across soil profiles. In three seasons, stochasticity-dominated processes in spring and summer changed into determinism-dominated processes in winter. These findings extend our knowledge of the response of the bacterial pathogenic community to environmental disruptions brought on by organic contaminated sites.

Marine Pollution and Advances in Biomonitoring in Cartagena Bay in the Colombian Caribbean

Coastal zones sustain extensive biodiversity, support key processes for ocean dynamics, and influence the balance of the global environment. They also provide resources and services to communities, determine their culture, and are the basis for their economic growth. Cartagena Bay in the Colombian Caribbean is the place of the establishment of one of the country's main cities, which has a great historical and tourist attraction, and it is also the location of the main commercial port and a great variety of industries. Historically, it has been affected by several environmental impacts and intense pollution. This situation has gained the attention of different researchers, so herein is presented a literature review with a systematic approach using RStudio's bibliometrix on the presence of pollutants and the impact on biodiversity in recent decades, providing a critical analysis of the state of Cartagena Bay and its future needs to ensure its recovery and conservation. In addition, the socioeconomic dynamics related to the environmental state of Cartagena Bay are presented from the framework drivers, pressures, status, impacts, and responses (DPSIR). The update and critical understanding of the sources, fate, and effects of pollution are important not only for the knowledge of the status of this singular ecosystem but also to encourage future research and entrench evidence to support decision makers' actions. This review highlights that several pollutants that have been detected exceeding sediment quality guidelines, like As, Cd, Hg, and PAH, are also reported to bioaccumulate and cause damage throughout the trophic levels of the coastal environment. In addition, the potential use of sentinel species and biomarkers for their monitoring is discussed. Finally, the factors that cause pollution and threaten the state of the bay continue to exert pressure and impact; thus, there is a call for the further monitoring of this ecosystem and the strengthening of policies and regulations.

Changes in Lolium perenne L. rhizosphere microbiome during phytoremediation of Cd- and Hg-contaminated soils

The contamination of soil and water by metals such as mercury (Hg) and cadmium (Cd) has been increasing in recent years, because of anthropogenic activities such as mining and agriculture, respectively. In this work, the changes in the rhizosphere microbiome of Lolium perenne L. during the phytoremediation of soils contaminated with Hg and Cd were evaluated. For this, two soil types were sampled, one inoculated with mycorrhizae and one without. The soils were contaminated with Hg and Cd, and L. perenne seeds were sown and harvested after 30 days. To assess changes in the microbiome, DNA isolation tests were performed, for which samples were subjected to two-step PCR amplification with specific 16S rDNA V3-V4 primers (337F and 805R). With mycorrhizae, changes had been found in the absorption processes of metals and a new distribution. While with respect to microorganisms, families such as the Enterobacteriaceae have been shown to have biosorption and efflux effects on metals such as Hg and Cd. Mycorrhizae then improve the efficiency of removal and allow the plant to better distribute the absorbed concentrations. Overall, L. perenne is a species with a high potential for phytoremediation of Cd- and Hg-contaminated soils in the tropics. Inoculation with mycorrhizae modifies the phytoremediation mechanisms of the plant and the composition of microorganisms in the rhizosphere. Mycorrhizal inoculation and changes in the microbiome were associated with increased plant tolerance to Cd and Hg. Microorganism-assisted phytoremediation is an appropriate alternative for L. perenne.

Health risk assessment for human exposure to mercury species and arsenic via consumption of local food in a gold mining area in Colombia

The risk to human health from exposure to certain pollutants through the consumption of fruits, tubers, and fish were evaluated in a settlement located in a Colombian area highly impacted by gold mining activities. The concentrations of mercury (Hg) and arsenic (As) in edible food tissues and methylmercury (MeHg) in fish were determined for risk assessment. A questionnaire-based dietary survey was answered by 178 residents of three population groups: children (CHD), women of childbearing age (WCBA), and the rest of the population (RP). The estimated weekly intake (EWI) of MeHg presented values of 1.9 and 2.4 times higher than the provisional tolerable weekly intake (1.6 μg/kg BW/week) recommended by the FAO/WHO for CH and WCBA, respectively. The results of the HQ values of As and Hg for different food were above the safety level (HQ < 1) for most of the groups. For Hg, the highest HQ values correspond to fish, whereas for As in most of the food, but specially in fruits. The total target hazard quotients (HI) were higher than 1, in all the groups (except for CHD that consume tubers) indicating potential non-carcinogenic health risks. The values of carcinogenic risk (CR) for As through exposure to food ranged from 1.2·10^-4 to 7.7·10^-4, well above than the safety level of US EPA risk (10^-4-10^-6), suggesting the probability of carcinogenic risk for the entire population via ingestion. Therefore, safety control mechanisms and environmental education strategies should be applied to address food intake, associated with good agricultural practices to provide solutions to protect the health of the residents in areas affected by gold mining activities.

Pollution pressure and soil depth drive prokaryotic microbial assemblage and co-occurrence patterns in an organic polluted site

Organic polluted sites have become a global concern of soil contamination, yet little is known about microbial vertical distribution and community assembly in organic polluted sites. Here, high-throughput sequencing technology was employed to investigate prokaryotic microbial diversity and community assembly along soil profile in an abandoned chemical organic contaminated site. Results showed that there was no significant difference (P > 0.05) observed in microbial alpha diversity among different soil layers, whereas the structure of microbial communities presented significantly different (P < 0.05) in the superficial layer (0-0.5 m) compared with intermediate (1-1.5 m) and bottom (2.5-3 m) layers. Soil prokaryotic microbial community evolved to possess the potential of degrading organic pollutants under long-term organic pollution stress. A relatively homogeneous environment created by the organic polluted site mainly induced the ecological process of homogeneous selection driving community assembly, while dispersal limitation gained importance with the increase of soil depth. Organic contaminants were identified as the key driver of destabilizing co-occurrence networks, while the frequent cooperative behaviors among species could combat organic pollution stress and sustain prokaryotic community stability. Collectively, pollution pressure and soil depth jointly affected prokaryotic microbial assemblage and co-occurrence that underpinned the spatial scaling patterns of organic contaminated sites microbiota.

Pollution assessment and mapping of potentially toxic elements (PTE) distribution in urban wastewater fed natural wetland, Kolkata, India

East Kolkata Wetland (EKW) is one of the largest sewage-fed wetlands in the world, which support the livelihood of thousands of peoples. However, at present, EKW system has become ecologically vulnerable due to the discharge of toxic waste through the sewage canal from the Kolkata metropolitan city. Hence, it becomes very important to understand the inflow and load of potentially toxic elements (PTE) in the sediment, water, and fish of sewage-fed wetland used for aquaculture activities. In this study, one of the polluted wetland from EKW, Sardar bherry, was selected as the study area. Sediment samples (45) were collected from 15 sites to characterize the PTEs concentrations levels utilizing inductively coupled plasma mass spectrometry, and their spatial distribution pattern and pollution quality indices were estimated. Water (45) and fish (7) samples were also analyzed to understand the distribution pattern of PTEs from sediment to water and water to fish. The geostatistical prediction map showed that the concentration range of Cr, Fe, Cu, Co, Zn, Cd, Ni, Pb, and Mn in sampling stations were 27.3-84.1 μg g^-1, 7281-30193 μg g^-1, 50.6-229.7 μg g^-1, 4.8-15.3 μg g^-1, 113.4-776.9 μg g^-1, 10.0-26.9 μg g^-1, 23.8-55.7 μg g^-1, 9.5-39.3 μg g^-1, and 188.6-448.5 μg g^-1 respectively. Pollution is alarming in sediment as all of the studied PTEs exceed the threshold effect level according to Sediment Quality Guidelines. Cd levels in sediments were found to be upper than the lowest effect level (LEL), probable effect level (PEL), threshold effect level (TEL), and severe effect level (SEL) for all sample locations. Several pollution assessment indexes (contamination factor, geo-accumulation index, ecological risk index, etc.) also showed that sediment samples were severely polluted by Cd. PTEs status in water and fish is within permissible limits. The study emphasizes that attention should be paid to controlling the excessive accumulation of PTEs in sediment that would further harm the ecological environment and ultimately human health.

Human health risk-based soil environmental criteria (SEC) for park soil in Beijing, China

Urban parks are important places that allow urban residents to experience nature but are also associated with the risk of exposure to contaminated soil. Therefore, it is necessary to establish appropriate soil environment criteria (SEC) to manage park soil quality. Studies on the demographic characteristics and behavioral patterns of urban park visitors are helpful for the selection of sensitive receptors and the determination of parameters in the establishment of SEC. This study explored the park visitors' demographic characteristics and behavioral patterns, and applied the results to derive SEC. Eighty-six parks in Beijing were selected, and mobile phone data were obtained to analysis the demographic characteristics and residence time of the visitors. Kruskal-Wallis test, kernel density estimation and random forest model were used for data analysis. The CLEA model was used to derive SEC. The results showed that the demographic characteristics and behavioral patterns of visitors in different types of parks were quite different. Parks were mostly used by males and visitors aged 31-45. Most visitors stayed in the park for 1-2 h, and the distance from a given visitor's home to the park was the most important factor affecting stay time. Then, several parameters such as the parameters related to the receptors and occupation period were optimized, and the SEC of sensitive parks and non-sensitive parks were derived. Exposure frequency may be the main reason for the difference of SEC between the two types of parks. The SECs of sensitive parks were higher than the soil screening values (SSVs) for class 1 land in GB36600-2018, indicating that the current SSVs for some parks may be too conservative. This study provides a reference for the formulation and revision of soil environmental standards for park land, and suggests strengthening research on human behavioral patterns.

Cement kiln co-processing promotes the redevelopment of industrially contaminated land in China: Spatio-temporal features and efficiency analysis

The cleanup and redevelopment of industrially contaminated land are essential for sustainable urban development, both from economic and environmental perspectives. Remediation efforts in developed countries have incurred high decontamination costs and administrative, monitoring, and enforcement requirements that are beyond the capabilities of many developing nations. Here, we reviewed the development of cement kiln co-processing of contaminated soils, a commonly used remediation strategy in China, and discussed the spatio-temporal features, benefits and efficiency of co-processing. Our results show that urbanization, the real estate market, and policies have impacts on the development of technology. By June 2021, cement kiln co-processing has disposed of approximately 2,633, 823 m³ of contaminated soils, and the average feed rates of organic pollutants, combined pollution, and heavy metals are 6%, 4%, and 3%, respectively. The average cost of co-processing contaminated soil is US$167.2 per cubic meter, which is lower than that of other conventional remedies. Based on the pollution status and cement production capacity, it is most likely that the co-processing strategy will be adopted by three countries of India, Indonesia, and Vietnam in the next few years. In the future, more data will be needed to quantify and assess the technology diffusion at the provincial level and the technological details of adopting this strategy.

Remediation of soil cadmium pollution by biomineralization using microbial-induced precipitation: a review

In recent years, with industrial pollution and the application of agricultural fertilizers with high cadmium (Cd) content, soil Cd pollution has become increasingly serious. A large amount of Cd is discharged into the environment, greatly endangering the stability of the ecological environment and human health. The use of microorganisms to induce Cd precipitation and mineralization is an important bioremediation method. Itis highly efficient, has a low cost, enables environmental protection, and convenient to operate. This article summarizes the pollution status, pollution source, biological toxicity and existing forms of Cd, as well as the biomineralization mechanism of microbial induced Cd(II) precipitation, mainly including microbial-induced carbonate precipitation, microbial-induced phosphate precipitation and microbial-induced sulfide precipitation. Factors affecting the bioremediation of Cd, such as pH, coexisting ions, and temperature, are introduced. Finally, the key points and difficulties of future microbe-induced Cd(II) biomineralization research are highlighted, providing a scientific basis and theoretical guidance for the application of microbe-induced Cd(II) immobilization in soil.

Seven potential sources of arsenic pollution in Latin America and their environmental and health impacts

This review presents a holistic overview of the occurrence, mobilization, and pathways of arsenic (As) from predominantly geogenic sources into different near-surface environmental compartments, together with the respective reported or potential impacts on human health in Latin America. The main sources and pathways of As pollution in this region include: (i) volcanism and geothermalism: (a) volcanic rocks, fluids (e.g., gases) and ash, including large-scale transport of the latter through different mechanisms, (b) geothermal fluids and their exploitation; (ii) natural lixiviation and accelerated mobilization from (mostly sulfidic) metal ore deposits by mining and related activities; (iii) coal deposits and their exploitation; (iv) hydrocarbon reservoirs and co-produced water during exploitation; (v) solute and sediment transport through rivers to the sea; (vi) atmospheric As (dust and aerosol); and (vii) As exposure through geophagy and involuntary ingestion. The two most important and well-recognized sources and mechanisms for As release into the Latin American population's environments are: (i) volcanism and geothermalism, and (ii) strongly accelerated As release from geogenic sources by mining and related activities. Several new analyses from As-endemic areas of Latin America emphasize that As-related mortality and morbidity continue to rise even after decadal efforts towards lowering As exposure. Several public health regulatory institutions have classified As and its compounds as carcinogenic chemicals, as As uptake can affect several organ systems, viz. dermal, gastrointestinal, peptic, neurological, respiratory, reproductive, following exposure. Accordingly, ingesting large amounts of As can damage the stomach, kidneys, liver, heart, and nervous system; and, in severe cases, may cause death. Moreover, breathing air with high As levels can cause lung damage, shortness of breath, chest pain, and cough. Further, As compounds, being corrosive, can also cause skin lesions or damage eyes, and long-term exposure to As can lead to cancer development in several organs.

A coupled optimization of groundwater remediation alternatives screening under health risk assessment: An application to a petroleum-contaminated site in a typical cold industrial region in Northeastern China

Contaminated sites have been recognized as posing serious comprehensive social and environmental issues and have earned worldwide attention. China is becoming one of the largest contaminated sites remediation markets in the world and the contaminated sites in northeastern China need to rehabilitate urgently. However, remediation planning is often hindered by high financial costs resulting from incomplete assessments of pollution and inappropriate remediation plans. In-depth contaminated site assessments can provide the necessary baseline data for remediation alternatives screening. Therefore, risk assessments and remediation decisions will play crucial roles in the rehabilitation and reconstruction of contaminated sites in China. The main objectives of this study were to present a novel method for health risk assessment (HRA) and to demonstrate a multicriteria decision analysis (MCDA) based on this method to select the most suitable remediation alternatives of groundwater and to prioritize management of contaminated site. To demonstrate the HRA and MCDA processes, a typical contaminated site in Longtan, Jilin province, China, was used. The results of this research indicated that Benzene (PhH) and 1,2-Dichloroethylene (1,2-DCE) were the main organic pollutants and the vanillin plant in the north of the site was main pollution source. Pollution migrated from the north to the south and the health risk range in winter was significantly greater than in summer. Four remediation alternatives were proposed on the basis of the HRA results. The MCDA results showed that PRB was the most suitable technology for integrating the relevant environmental, social, economic, and technical aspects required for remediation. This study may help responsible agencies to strengthen local risk-based program screening frameworks for contaminated sites, to promote reconstruction projects, and to increase local public confidence of contaminated sites remediation.

Spatio-Econometric Analysis of Urban Land Use Efficiency in China from the Perspective of Natural Resources Input and Undesirable Outputs: A Case Study of 287 Cities in China

The rapid urbanization in China has had a huge impact on land use and the scarcity of land resources has become a constraint for sustainable urban development. As urban land is an indispensable material basis in economic development, measuring its use efficiency and adopting effective policies to improve urban land use efficiency (ULUE) are important links in maintaining sustainable economic growth. By establishing a comprehensive ULUE evaluation index system that emphasizes on incorporating the natural resources input and the undesirable output, ULUE from 2010 to 2016 was calculated based on super efficiency SBM model, and its potential influencing factors were explored using a spatial econometric model. The results show that: (1) temporally, the overall ULUE in China is upward growing, and the gap among regions is becoming gradually convergent. (2) Spatially, the ULUE of Chinese cities are positively correlated. (3) Economic agglomeration and industrial structure significantly improve ULUE in China, but the intensity of energy consumption has a negative impact on ULUE. We suggest that: (1) differentiated industrial development strategies should be formulated; (2) the economic growth pattern should be changed from energy-consuming to energy-saving; (3) priority should be given to innovation on science and education, so as to increase in clean energy input and cleaner production.

Determination of organochlorine and organophosphorus residues in surface waters from the coffee zone in Quindío, Colombia

The aim of this study was to identify organochlorine (OC) and organophosphorus (OP) pesticides levels in water samples collected in secondary water bodies in agricultural area planted with coffee and plantain. A descriptive cross-sectional study was carried out. A validated method for microwave-assisted extraction and gas chromatography with electron microcapture detector (MAE-GC-μECD) was used to analyze pesticide residues in samples. The determinations were based on certified reference material, Organochlorine Pesticide Mix AB #3, Canadian Drinking Organophosphorus Pesticides Mix, and pentachloronitrobenzene (ISTD) Internal Standard Mix 508.1. Pesticide residues were found in 81.3% of the samples, including OCs: 4.4'-DDT (38%), endosulfan II (19.7%), endosulfan sulfate, and endrin (11.7% and 8.8%), and others identified as 4.4'-DDE, Delta-HCB, parathion, chlorpyrifos, endrin aldehyde, heptachlor, heptachlor epoxide, endrin ketone, and methoxychlor. Parathion and/or chlorpyrifos were found in 5.8-8% of samples; the water bodies most heavily affected were those in Filandia and Quimbaya in which 100% of samples were contaminated, followed by those in Calarcá, Córdoba, Pijao, and Génova, with contamination found in over 75% of samples. The results indicated that surface waters from Quindío municipalities are contaminated with pesticide residues hazardous to human health, which are still in use despite being either restricted or prohibited.

AISLAMIENTO E IDENTIFICACIÓN DE Lactobacillus spp. (LACTOBACILLACEAE) RESISTENTES A Cd(II) Y As(III) RECUPERADOS DE FERMENTO DE CACAO

El objetivo de este estudio fue aislar e identificar a partir de cacao fermentado en Caldas Colombia, bacterias con potencial de aplicación en procesos biotecnológicos, como la detoxificación de cadmio (Cd(II)) y arsénico (As(III)) en el organismo humano. En total se recuperaron 36 aislados de los cuales se recuperaron 11 en presencia de 1,0 mg/L de Cd(II) y 25 en presencia de 0,1 mg/L de As(III). Su identificación molecular determinó que la mayoría de los aislados son del género Lactobacillus. Los ensayos de crecimiento en presencia de diferentes concentraciones de los elementos evaluados permitió determinar que gran parte de los aislamientos presentan resistencia a mayores concentraciones de As(III) (300 mg/L) que de Cd(II) (10 mg/L). En ensayos de tolerancia a la acidez (pH 2,5) se encontró que la cepa tipo Lactobacillus plantarumJCM 1055, junto con los aislamientos nativos L. plantarumA19, A26 y C16, mostraron la mayor tolerancia, por lo que se seleccionaron para evaluar su tolerancia a condiciones de salinidad. Las bacterias evaluadas mostraron crecimiento en concentraciones de hasta 4 g/L de sales biliares. Se concluye que los L. plantarumevaluados en este trabajo tienen un gran potencial para futuros ensayos en los que se busque demostrar la disminución de la bioaccesibilidad de Cd(II) y As(III) en condiciones in vitro del sistema digestivo humano debido a su resistencia a altas concentraciones de estos elementos y su tolerancia a condiciones de acidez y salinidad. Esto, junto con el reconocido potencial probiótico que tienen estos microorganismos, permitirá a futuro su uso en procesos biológicos de mitigación de Cd(II) y As(III).

Greening the Browns: A Bio-Based Land Use Framework for Analysing the Potential of Urban Brownfields in an Urban Circular Economy

The Circular Economy (CE) is expected to accelerate the use of resources with bio-based origin. Cities have an important role in such an economy, not only as main consumers but also because vegetation provides numerous ecosystem services essential for the well-being of urban dwellers. Urban lands are, however, heavily burdened with both past and present activities and ongoing urbanization. Retrofitting obsolete and potentially contaminated brownfields provides an opportunity to engage with bio-based land uses within the city. At the same time, plants are an important part of Gentle Remediation Options (GROs), a more sustainable alternative for managing contamination risks and restoring soil health. This paper (1) provides a tentative selection of Urban Greenspaces (UGSs) relevant for brownfields, and a compilation of ecosystem services provided by the selected UGSs, and (2) presents a framework covering the 14 selected bio-based land uses on brownfields, including GRO interventions over time. This framework provides three practical tools: the conceptualization of linkages between GROs and prospective UGS uses, a scatter diagram for the realization of 14 UGS opportunities on brownfields, and a decision matrix to analyze the requirements for UGS realization on brownfields.

Fish as bioindicators: coal and mercury pollution in Colombia's ecosystems

Mining in Colombia affects 488,672 ha (298,391 in coal mining and 190,281 in gold mining). However, Colombia has insufficient studies on mining and its repercussions, which limits estimates of mining impacts on ecosystems and the human population. Due to the rise of mining activities in Colombia, the negative impacts generated by coal and Hg will also continue to increase. This review analyzes national information levels on coal and Hg in island/coastal/marine as well as freshwater ecosystems and human groups using fishery resources as a framework. This is because fish are the main source of animal protein in marine coastal-island and mainland communities. Here, 15 of 32 Colombian departments have records on total mercury (THg) in water, sediments, fish, and human communities. Around 205 ton/year of mercury is discharged into the ecosystem. In human hair for example (15.3 to 50.15 μg/g), mercury exceeds the international maximum levels allowed (ILA) and the national standard (5.0 μg/g). Mercury levels in freshwater fish show 3.3 μg/g of THg and levels in marine and coastal-island fish are 1.2 μg/g THg exceeding the ILA (0.5 μg/g) standard for fish that will be consumed. Carnivorous species have a THg between 0.04 and 2.55 μg/g suggesting bioaccumulation and magnification of heavy metals. These findings were then compared with available international information.

Assessment of mining activity on arsenic contamination in surface water and sediments in southwestern area of Santurbán paramo, Colombia

The current emphasis of developing countries on policies that favor the intensification of mining exploitation as the main source of incomes, has generated negative consequences for ecosystems and rural communities, mainly due to the release of highly toxic elements into the environment. This study was carried out to evaluate the effect of the Vetas-California gold mining district on As distribution in stream sediments and surface water samples from Suratá River, located in the southwestern area of Santurbán paramo, Colombia. With this aim, samples distributed along the high Suratá River basin in areas near and far from mining areas were selected. Samples were chemically characterized. The As mobility, enrichment and sources were evaluated using sequential and single extractions, enrichment factor (EF), geoaccumulation index (I_geo), and hierarchical cluster analysis (HCA). The results highlight high As content (reaching up to 484 mg/kg) in stream sediment sampled near the gold mining district. For both sediment and water, the relative As content along the Suratá River exceeded the background content by 220 and 64.9 times, respectively. From the single-stage extractions performed, the reducible fractions found in As(NaOH) and As(HCl) were higher in all cases, meaning a high level of mobility and lixiviation of the As content in water samples by changes in pH and redox potentials. The correlations estimated using Spearman coefficients show that most of the bioavailable fraction of As(Exch) is related to main sediment constituents such as S, Fe₂O₃, SiO₂, and Al₂O₃ and the relative As content. Calculation of the enrichment factor (EF) confirms high enrichments around active sites of gold mining such as the municipalities of Vetas, California and Matanza with EF values of 285, 204, and 133, respectively. In addition, the I_geo values suggest moderate to strong As pollution due to the high I_geo found at the major mining effect points. The findings from this study are valuable for providing effective management options for risk prevention and control of the persistent As accumulation in Santurbán paramo.

Synergistic effect of Lysinibacillus sphaericus and glyphosate on temephos-resistant larvae of Aedes aegypti

BACKGROUND

Glyphosate-based herbicides are one of the most commonly used compounds to control perennial weeds around the world. This compound is very persistent in the environment and tends to filter into aquatic ecosystems, affecting non-target species such as mosquito larvae. Aedes aegypti mosquitoes are vectors of multiple arboviruses such as dengue and Zika. Glyphosate can be degraded into non-harmful environmental compounds by Lysinibacillus sphaericus, a spore forming bacterium which can also kill Ae. aegypti larvae. In this study, we assessed the effect of glyphosate concentrations, typically used in Colombia, on the entomopathogenic activity of L. sphaericus against Ae. aegypti larvae.

METHODS

Bioassays and toxicity curves were performed to compare the larval mortality between different treatments with and without bacteria and glyphosate (Roundup 747®). Larvae were exposed to both bacteria and glyphosate by adding the compound on chloride-free water. Comparisons were made using both probit regression and ANOVA analysis.

RESULTS

ANOVA showed a significant difference in larval mortality when adding glyphosate and L. sphaericus at the same time. Thus, a positive synergic effect on larval mortality was found when L. sphaericus and glyphosate were mixed. According to probit analysis, median lethal dose (LD50) for bacterial mixture was of 106.23 UFC/ml and for glyphosate was 2.34 g/l.

CONCLUSIONS

A positive synergic effect on the mortality of larval Ae. aegypti when exposed to L. sphaericus mixture and glyphosate was found. Molecular studies focusing on the toxin production of L. sphaericus are required to understand more about this synergistic effect.

Legal measures to prevent and manage soil contamination and to increase food safety for consumer health: The case of Spain

This article contains a brief overview of the European and Spanish environmental law framework for the prevention of soil contamination, for the management of contaminated soils and for consumers health protection in relation to agricultural crops. Some important aspects of the legislative framework for the prevention and management of soil contamination include recognising the possible risk to both human health and ecosystems that certain agricultural and industrial activities pose given the use of organic and inorganic chemical substances of a hazardous nature and pathogenic microorganisms. It is worth highlighting the milestone that many national constitutions include about the right to the environment. This right entails the obligation to protect it and to, therefore, protect soil from any degradation, including contamination. Legislation that protects soil from contamination and, consequently human health and ecosystems, is related mainly to agricultural activities (use of sewage sludge on farmlands, use of wastewater for irrigation, use of organic fertilisers and pesticides), and to industrial and commercial soil-contaminating activities. Consumer protection may be achieved through a legal system of environmental liability, specific measures to prevent contaminants entering soil, managing contaminated soils and a food traceability system. It is crucial to make the penalties for soil contamination offenses, and for violators of protective prohibitions, effective, proportionate and dissuasive. Global standards and guidelines on soil contamination could provide national legislative systems with substantive and procedural legal mechanisms to help prevent and manage soil contamination.

Enhancement of gasworks groundwater remediation by coupling a bio-electrochemical and activated carbon system

Here, we show the electrical response, bacterial community, and remediation of hydrocarbon-contaminated groundwater from a gasworks site using a graphite-chambered bio-electrochemical system (BES) that utilizes granular activated carbon (GAC) as both sorption agent and high surface area anode. Our innovative concept is the design of a graphite electrode chamber system rather than a classic non-conductive BES chamber coupled with GAC as part of the BES. The GAC BES is a good candidate as a sustainable remediation technology that provides improved degradation over GAC, and near real-time observation of associated electrical output. The BES chambers were effectively colonized by the bacterial communities from the contaminated groundwater. Principal coordinate analysis (PCoA) of UniFrac Observed Taxonomic Units shows distinct grouping of microbial types that are associated with the presence of GAC, and grouping of microbial types associated with electroactivity. Bacterial community analysis showed that β-proteobacteria (particularly the PAH-degrading Pseudomonadaceae) dominate all the samples. Rhodocyclaceae- and Comamonadaceae-related OTU were observed to increase in BES cells. The GAC BES (99% removal) outperformed the control graphite GAC chamber, as well as a graphite BES and a control chamber both filled with glass beads.