Complex adaptive systems-based framework for modeling the health impacts of climate change.

Introduction: Climate change is a global phenomenon with far-reaching consequences, and its impact on human health is a growing concern. The intricate interplay of various factors makes it challenging to accurately predict and understand the implications of climate change on human well-being. Conventional methodologies have limitations in comprehensively addressing the complexity and nonlinearity inherent in the relationships between climate change and health outcomes. Objectives: The primary objective of this paper is to develop a robust theoretical framework that can effectively analyze and interpret the intricate web of variables influencing the human health impacts of climate change. By doing so, we aim to overcome the limitations of conventional approaches and provide a more nuanced understanding of the complex relationships involved. Furthermore, we seek to explore practical applications of this theoretical framework to enhance our ability to predict, mitigate, and adapt to the diverse health challenges posed by a changing climate. Methods: Addressing the challenges outlined in the objectives, this study introduces the Complex Adaptive Systems (CAS) framework, acknowledging its significance in capturing the nuanced dynamics of health effects linked to climate change. The research utilizes a blend of field observations, expert interviews, key informant interviews, and an extensive literature review to shape the development of the CAS framework. Results and discussion: The proposed CAS framework categorizes findings into six key sub-systems: ecological services, extreme weather, infectious diseases, food security, disaster risk management, and clinical public health. The study employs agent-based modeling, using causal loop diagrams (CLDs) tailored for each CAS sub-system. A set of identified variables is incorporated into predictive modeling to enhance the understanding of health outcomes within the CAS framework. Through a combination of theoretical development and practical application, this paper aspires to contribute valuable insights to the interdisciplinary field of climate change and health. Integrating agent-based modeling and CLDs enhances the predictive capabilities required for effective health outcome analysis in the context of climate change. Conclusion: This paper serves as a valuable resource for policymakers, researchers, and public health professionals by employing a CAS framework to understand and assess the complex network of health impacts associated with climate change. It offers insights into effective strategies for safeguarding human health amidst current and future climate challenges.

Planetary health & COVID-19: A multi-perspective investigation.

COVID-19 can be characterized as an outcome of degraded planetary health drivers in complex systems and has wide-reaching implications in social, economic and environmental realms. To understand the drivers of planetary health that have influences of emergence and spread of COVID-19 and their implications for sustainability systems thinking and a narrative literature review are deployed. In particular, sixteen planetary health drivers are identified, i.e., population growth, climate change, agricultural intensification, urbanization, land use and land cover change, deforestation, biodiversity loss, globalization, wildlife trade, wet markets, non-planetary health diet, antimicrobial resistance, air pollution, water stress, poverty and weak governance. The implications of COVID-19 for planetary health are grouped in six categories: social, economic, environmental, technological, political, and public health. The implications for planetary health are then judged to see the impacts with respect to sustainable development goals (SDGs). The paper indicates that sustainable development goals are being hampered due to the planetary health implications of COVID-19.

COVID-19's implications on agri-food systems and human health in Bangladesh.

The COVID-19 pandemic in Bangladesh has put agri-food systems and resultant human health under serious pressure and this has thus become a priority concern for the country and its development partners. To understand, describe and analyse the impacts of COVID-19 on agri-food systems, human health issues and related SDGs, this study used systematic rapid literature review, analysis of blogs and news and engagement with key informants. The analysis reveals impacts that can be addressed through a set of recommendations for a coordinated effort to minimize the effects of the COVID-19 pandemic on agri-food systems and related health issues in Bangladesh.

Emerging health risks associated with modern agriculture practices: a comprehensive study in India.

In order to enhance food production, India has adopted modern agriculture practices and achieved noteworthy success. This achievement was essentially the result of a paradigm shift in agriculture that included high inputs of agrochemicals, water, and widespread practice of monoculture, as well as bureaucratic changes that promoted these changes. There are very few comprehensive analyses of potential adverse health outcomes that may be related to these changes. The objective of this study is to identify health risks associated with modern agricultural practices in the southern Indian state of Karnataka. This study aims to compare high-input and low-input agricultural practices and the consequences for health of people in these communities. The fieldwork was conducted from May to August, 2009 and included a survey carried out in six villages. Data were collected by in-depth personal interviews among 240 households and key informants, field observations, laboratory analyses, and data from secondary sources. The study identified four major visible impacts: occupational hazards, vector borne diseases, changing nutritional status, and inequity in development. In the high-input area, mechanization has resulted in more occurrences of serious accidents and injuries. Ecological changes due to rice cultivation in this area have further augmented mosquito breeding, and there has been a surge in the incidence of Japanese encephalitis and malaria. The traditional coarse cereals (complex carbohydrates, high protein) have been replaced by mill-polished rice (simple carbohydrate, low protein). The prevalence of overweight (BMI>25) has emerged as a new public health challenge, and this is most evident in large-landholding households, especially in the high-input agriculture areas. In all agro-ecological areas, it was observed that women faced a greater risk of both extremes of under-nutrition and being overweight. Output-driven and market-oriented modern agricultural practices have changed the ecology and disease pattern in this area in India, and our survey indicated significant health effects associated with these changes. There is a need for more extensive epidemiological studies in order to know the full impact on diseases and to understand the complex causal relationships.

Degradation of the pesticide fenitrothion as mediated by cationic surfactants and alpha-nucleophilic reagents.

The reaction of fenitrothion with a series of alpha-nucleophile oximates having pK(a) values in the range of 7.7-11.8 was studied both in the absence and presence of cetyltrimethylammonium (CTA(+)) surfactants. Reaction with CTA-oximates was found to proceed through two pathways: S(N)2(P) and S(N)2(C); an S(N)Ar pathway was not observed. Accordingly, the observed rate constants were dissected into the two corresponding S(N)2(P) and S(N)2(C) pathways. Use of the pseudophase ion exchange (PPIE) model for micellar catalysis in the CTA(+) system allowed evaluation of micellar second-order rate constant (k(2m)) parameters and binding constants, (K(S)). K(S) values for CTA-oximates were found to vary with the counterion, and the rate enhancement depended on a combination of K(S) and k(2m) values. k(2m)/k(2w) values ranged from 0.0025 to 0.64, suggesting that a concentration effect is mainly responsible for the rate enhancement. In the absence of surfactant, an alpha-effect (i.e., k(alpha)/k(normal)) varying from 8 to 450 was observed for the oximate reaction, decreasing with increasing pK(a). It is proposed that differential solvation (transition-state imbalance) is a cause of the alpha-effect in this system.

Micellar catalyzed degradation of fenitrothion, an organophosphorus pesticide, in solution and soils.

We report on a study of the decomposition of fenitrothion (an organophosphorus pesticide that is a persistent contaminant in soils and groundwater) as catalyzed by cetyltrimethylammonium (CTA+) micelles. The CTA micelles were associated with two types of counterions: (1) inert counterions (e.g. CTABr) and (2) reactive counterions (e.g. CTAOH). The reactive counterion surfactants used were hydroxide anion (HO-) as a normal nucleophile and hydroperoxide anion (HOO-) and the anion of pyruvaldehyde oxime (MINA-) as two alpha-nucleophiles. The reactivity order followed: CTABr < CTAOH < CTAMINA << CTAOOH. Treatment of the rate data using the Pseudo-Phase Ion Exchange (PPIE) model of micellar catalysis showed the ratio k2M/k2w to be less than unity for all the surfactants employed. Rather than arising from a "true catalysis", we attributed the observed rate enhancements to a "concentration effect", where both pesticide and nucleophile were incorporated into the small micellar phase volume. Furthermore, the CTAOOH/CTAOH pair gave an alpha-effect of 57, showing that the alpha-effect can play an important role in micellar systems. We further investigated the effectiveness of reactive counterion surfactants in decontaminating selected environmental solids that were spiked with 27 ppb fenitrothion. The solids were as follows: the clay mineral montmorillonite and SO-1 and S0-2 soils (obtained from the Canadian Certified Reference Materials Project). The reactive counterion surfactant solutions significantly enhanced the rate of fenitrothion degradation in the spiked solids over that obtained when the spiked solid was placed in contact with either 0.02 M KOH or water. The rate enhancements followed the order CTAOOH >> CTAMINA approximately CTAOH > KOH >> water. We conclude that reactive counterion surfactants, especially with alpha-nucleophiles, hold great potential in terms of remediating soils contaminated by toxic organophosphorus esters.

Acceleration of nucleophilic attack on an organophosphorothioate neurotoxin, fenitrothion, by reactive counterion cationic micelles. Regioselectivity as a probe of substrate orientation within the micelle.

31P NMR and UV-vis spectrometric evidence has revealed an unexpected regioselectivity in the reaction of fenitrothion, 1, an organophosphorus pesticide, with the cetyltrimethylammonium (CTA) surfactants CTAOH and CTAMINA, that incorporate the reactive counterions OH- and MINA- (the anti-pyruvaldehyde 1-oximate anion). While both micellar solutions accelerate decomposition of 1 compared to aqueous OH- alone, CTAMINA produced the largest rate enhancement (ca. 10(5)) at a pH (8.39) appropriate for environmental applications. In the absence of surfactant, reaction proceeds solely via the SN2(P) pathway. In the presence of surfactant but below the critical micelle concentration (cmc), a competitive SN2(C) pathway was observed in addition to SN2(P). Above the cmc, however, the CTAOH reaction again proceeded solely via the SN2(P) pathway while both pathways were operative with CTAMINA. The changes in reactivity and mechanistic pathway are discussed in terms of premicellar and micellar influences on rates and regioselectivity. A proposal that would account for the observed regioselectivity in the micellar system is that the aromatic ring and aliphatic side-chains of 1 are oriented toward the micellar interior, while the P=S moiety faces the aqueous pseudophase.

Effects of raw water conditions on solution-state aluminum speciation during coagulant dilution.

The speciation of aluminum in solutions of alum and various prehydrolyzed, aluminum-based water treatment coagulants was investigated by 27Al NMR at 5 degrees C and 25 degrees C. Alum solutions were seen to contain only mononuclear species including an AlSO4(+) complex, while the prehydrolyzed coagulant solutions contained polynuclear aluminum species, as well. The relative proportions of both polynuclear species and AlSO4(+) complex decreased in cold water. The presence of organic matter had little effect on the speciation of aluminum in diluted alum, but markedly reduced the relative proportion of the tridecamer species in the prehydrolyzed coagulant solutions. The relationship between Al speciation in the coagulants and organic matter removal during jar tests was considered, and the possible role of sulfate in both the formation of the tridecamer species and the effect of organic matter on coagulation efficiency was discussed.

Degradation and sorption of pirimiphos-methyl in two Nigerian soils.

This research is a continuation of a study on the behavior of hydrophobic organic compounds in the environment and describes the simultaneous abiotic degradation and sorption of pirimiphos-methyl (O-2-diethylamino-6-methylpyrimidin-4-yl O,O-dimethylphosphorothioate) under controlled conditions in soil/water slurries. A microfiltration-HPLC technique was employed to follow these processes in two well-characterized soils from the Middle Belt region of Nigeria. Rapid sorption of the pesticide occurs during the first 10 min of equilibration and accounted for 37% of the original pirimiphos-methyl in the Rhodic Kandiustalf soil and for 41% of the original concentration in Aquic Ustropept soil. Subsequent slow processes were followed during the remaining 30 days of the experiment. During this time, first-order rate constants for disappearance from solution of pirimiphos-methyl were found to have values of 6.1 x 10(-)(7) and 9.8 x 10(-)(7) s(-)(1) for the Rhodic and Aquic soils, respectively. Similarly, rate constants for production of the product, pyrimidinol, were calculated to be 6.0 x 10(-)(7) and 9.4 x 10(-)(7) s(-)(1) for the Rhodic and Aquic soils, respectively, giving pesticide degradation half-lives of 13 and 8.5 days. Disappearance of the pesticide is discussed in terms of a scheme involving both sorptive uptake by the soil and degradation by hydrolysis in the presence of the soil matrix. The labile sorption capacities for pirimiphos-methyl in the Rhodic and Aquic soils were found to be 0.75 and 0.90 micromol g(-)(1), respectively.