More surprises in the global greenhouse: Human health impacts from recent toxic marine aerosol formations, due to centennial alterations of world-wide coastal food webs

Environmental factors influencing DDT-DDE spatial distribution in an agricultural drainage system determined by using machine learning techniques

The presence and persistence of pesticides in the environment are environmental problems of great concern due to the health implications for humans and wildlife. The persistence of DDT-DDE in a Mediterranean coastal plain where pesticides were widely used and were banned decades ago is the aim of this study. Different sources of analytical information from water and soil analysis and topography and geographical variables were combined with the purpose of analyzing which environmental factors are more likely to condition the spatial distribution of DDT-DDE in the drainage watercourses of the area. An approach combining machine learning techniques, such as Random Forest and Mutual Information (MI), for classifying DDT-DDE concentration levels based on other environmental predictive variables was applied. In addition, classification procedure was iteratively performed with different training/validation partitions in order to extract the most informative parameters denoted by the highest MI scores and larger accuracy assessment metrics. Distance to drain canals, soil electrical conductivity, and soil sand texture fraction were the most informative environmental variables for predicting DDT-DDE water concentration clusters.

Harmful algal bloom aerosols and human health

Harmful algal blooms (HABs) are increasing across many locations globally. Toxins from HABs can be incorporated into aerosols and transported inland, where subsequent exposure and inhalation can induce adverse health effects. However, the relationship between HAB aerosols and health outcomes remains unclear despite the potential for population-level exposures. In this review, we synthesized the current state of knowledge and identified evidence gaps in the relationship between HAB aerosols and human health. Aerosols from Karenia brevis, Ostreopsis sp., and cyanobacteria were linked with respiratory outcomes. However, most works did not directly measure aerosol or toxin concentrations and instead relied on proxy metrics of exposure, such as cell concentrations in nearby waterbodies. Furthermore, the number of studies with epidemiological designs was limited. Significant uncertainties remain regarding the health effects of other HAB species; threshold dose and the dose-response relationship; effects of concurrent exposures to mixtures of toxins and other aerosol sources, such as microplastics and metals; the impact of long-term exposures; and disparities in exposures and associated health effects across potentially vulnerable subpopulations. Additional studies employing multifaceted exposure assessment methods and leveraging large health databases could address such gaps and improve our understanding of the public health burden of HABs.

Anthropogenic and Biogenic Contributions to the Organic Composition of Coastal Submicron Sea Spray Aerosol

The organic composition of coastal sea spray aerosol is important for both atmospheric chemistry and public health but remains poorly characterized. Coastal waters contain an organic material derived from both anthropogenic processes, such as wastewater discharge, and biological processes, including biological blooms. Here, we probe the chemical composition of the organic fraction of sea spray aerosol over the course of the 2019 SeaSCAPE mesocosm experiment, in which a phytoplankton bloom was facilitated in natural coastal water from La Jolla, California. We apply untargeted two-dimensional gas chromatography to characterize submicron nascent sea spray aerosol samples, reporting ∼750 unique organic species traced over a 19 day phytoplankton bloom experiment. Categorization and quantitative compositional analysis reveal three major findings. First, anthropogenic species made up 30% of total submicron nascent sea spray aerosol organic mass under the pre-bloom condition. Second, biological activity drove large changes within the aerosolized carbon pool, decreasing the anthropogenic mass fraction by 89% and increasing the biogenic and biologically transformed fraction by a factor of 5.6. Third, biogenic marine organics are underrepresented in mass spectral databases in comparison to marine organic pollutants, with more than twice as much biogenic aerosol mass attributable to unlisted compounds.

Inhalable particle-bound marine biotoxins in a coastal atmosphere: Concentration levels, influencing factors and health risks

Characterizing marine biotoxins (MBs) composition in coastal aerosol particles has become essential to tracking sources of atmospheric contaminants and assessing human inhalable exposure risks to air particles. Here, coastal aerosol particles were collected over an almost 3-year period for the analysis of eight representative MBs, including brevetoxin (BTX), okadaic acid (OA), pectenotoxin-2 (PTX-2), domoic acid (DA), tetrodotoxin (TTX), saxitoxin (STX), ciguatoxin (CTX) and ω-Conotoxin. Our data showed that the levels of inhalable airborne marine biotoxins (AMBs) varied greatly among the subcategories and over time. Both in daytime and nighttime, a predominance of coarse-mode AMB particles was found for all the target AMBs. Based on the experimental data, we speculate that an ambient AMB might have multiple sources/production pathways, which include air-sea aerosol production and direct generation and release from toxigenic microalgae/bacteria suspended in surface seawater or air, and different sources may make different contribution. Regardless of the subcategory, the highest deposition efficiency of an individual AMB was found in the head airway region, followed by the alveolar and tracheobronchial regions. This study provides new information about inhalable MBs in the coastal atmosphere. The coexistence of various particle-bound MBs raises concerns about potential health risks from exposure to coastal air particles.

An experimental method for efficiently evaluating the size-resolved sampling efficiency of liquid-absorption aerosol samplers

Aerosol samplers are critical tools for studying indoor and outdoor aerosols. Development and evaluation of samplers is often labor-intensive and time-consuming due to the need to use monodisperse aerosols spanning a range of sizes. This study develops a rapid experimental methodology using polydisperse solid aerosols to evaluate size-resolved aerosol-to-aerosol (AtoA) and aerosol-to-hydrosol (AtoH) sampling efficiencies. Arizona Test Dust (diameter 0.5-20 µm) was generated and dispersed into an aerosol test chamber and two candidate samplers were tested. For the AtoA test, aerosols upstream and downstream of a sampler were measured using an online aerodynamic particle sizer. For the AtoH test, aerosols collected in sampling medium were mixed with a reference sample and then measured by the laser diffraction method. The experimental methodology were validated as an impressive time-saving procedure, with reasonable spatial uniformity and time stability of aerosols in the test chamber and an acceptable accuracy of absolute mass quantification of collected particles. Evaluation results showed that the AGI-30 and the BioSampler sampler had similar size-resolved sampling efficiencies and that efficiencies decreased with decreasing sampling flow rate. The combined evaluation of AtoA and AtoH efficiency provided more comprehensive performance indicators than either test alone. The experimental methodology presented here can facilitate the design and choice of aerosol sampler.

Atmospheric Benzothiazoles in a Coastal Marine Environment

Organic emissions from coastal waters play an important but poorly understood role in atmospheric chemistry in coastal regions. A mesocosm experiment focusing on facilitated biological blooms in coastal seawater, SeaSCAPE (Sea Spray Chemistry and Particle Evolution), was performed to study emission of volatile gases, primary sea spray aerosol, and formation of secondary marine aerosol as a function of ocean biological and chemical processes. Here, we report observations of aerosol-phase benzothiazoles in a marine atmospheric context with complementary measurements of dissolved-phase benzothiazoles. Though previously reported dissolved in polluted coastal waters, we report the first direct evidence of the transfer of these molecules from seawater into the atmosphere. We also report the first gas-phase observations of benzothiazole in the environment absent a direct industrial, urban, or rubber-based source. From the identities and temporal dynamics of the dissolved and aerosol species, we conclude that the presence of benzothiazoles in the coastal water (and thereby their emissions into the atmosphere) is primarily attributable to anthropogenic sources. Oxidation experiments to explore the atmospheric fate of gas-phase benzothiazole show that it produces secondary aerosol and gas-phase SO₂, making it a potential contributor to secondary marine aerosol formation in coastal regions and a participant in atmospheric sulfur chemistry.

Occurrence of Pesticides Associated with an Agricultural Drainage System in a Mediterranean Environment

Surface water pollution (as a result of pesticides) is a major problem, due to the negative impact on human health and ecosystems. The excessive use and persistence of surface water pollution in the environment may present a notable risk. In this article, DDT and its metabolite DDE hereafter, DDT–DDE), and a commonly used pesticide (herbicide) glyphosate, were analyzed in agricultural drainage waters; afterward, a spatial analysis was applied to identify potential areas of high pesticide occurrence in an agricultural Mediterranean coastal floodplain. The spatial distribution of banned (Directive 79/117/EEC), yet highly persistent pesticides in the environment, such as DDT (and metabolites), was compared with the (currently and mostly used) glyphosate. A sequence of various point patterns, spatial analysis methods, and non-parametric statistics, were computed to elucidate the pesticide pollution hotspots. As a reference value, almost 70% of the water samples were above the World Health Organization (WHO) guideline for DDT (and metabolites) for drinking water (1 µg/L), with a maximum of 6.53 µg/L. Our spatial analysis approach revealed a significantly high concentration of DDT–DDE clusters close to wetlands in natural parks, where mosquitos are abundant, and pesticides persist and flow to the surface waters from soil and groundwater pools. Conversely, glyphosate concentrations were below WHO guidelines; their spatial patterns were related more toward current agricultural uses in the southern sector of the study area.

Levels of Phthalates, Bisphenol-A, Nonylphenol, and Microplastics in Fish in the Estuaries of Northern Taiwan and the Impact on Human Health

Due to the sparsity in knowledge, we investigated the presence of various estrogenic endocrine-disrupting chemicals (EEDCs), including phthalates (PAEs), bisphenol-A (BPA), and nonylphenol (NP), as well as microplastics (MPs) in samples of the most widely consumed fish collected from different estuaries in northern Taiwan. We then proceeded to determine the likely contribution that this exposure has on the potential for health impacts in humans following consumption of the fish. Six hundred fish caught from five river estuaries (producing 130 pooled samples) were analyzed to determine how different factors (such as the river, benthic, pelagic, and migratory species) influence EEDCs’ contamination and the possible impacts on human health following typical consumption patterns. The predominant EEDCs was diethyl phthalates (DEP), bis (2-ethylhexyl) phthalates (DEHP), and di-iso-nonylphthalate (DINP) in fish, present at 52.9 ± 77.3, 45.3 ± 79.8, and 42.5 ± 79.3 ng/g dry weight (d.w.), respectively. Residual levels of NP, BPA, and MPs in the fish were 17.4 ± 29.1 and 1.50 ± 2.20 ng/g d.w. and 0.185 ± 0.338 mg/g d.w., respectively. EEDCs and MPs levels varied widely among the five river estuaries sampled due, in part, to differences in habitat types and the associated diversity of fish species sampled. For DEP, the Lao-Jie River and pelagic environments produced the most severely contaminated fish species, respectively. DEP residues were also associated with the burden of MPs in the fish. Based on our analysis, we predict no substantial direct human health risk by EEDCs based on typical consumption rates of estuarine fish by the Taiwanese people. However, other sources of EEDC exposure cannot be ignored.

Toxic Cyanobacteria: A Growing Threat to Water and Air Quality

The global expansion of harmful cyanobacterial blooms (CyanoHABs) poses an increasing threat to public health. CyanoHABs are characterized by the production of toxic metabolites known as cyanotoxins. Human exposure to cyanotoxins is challenging to forecast, and perhaps the least understood exposure route is via inhalation. While the aerosolization of toxins from marine harmful algal blooms (HABs) has been well documented, the aerosolization of cyanotoxins in freshwater systems remains understudied. In recent years, spray aerosol (SA) produced in the airshed of the Laurentian Great Lakes (United States and Canada) has been characterized, suggesting that freshwater systems may impact atmospheric aerosol loading more than previously understood. Therefore, further investigation regarding the impact of CyanoHABs on human respiratory health is warranted. This review examines current research on the incorporation of cyanobacterial cells and cyanotoxins into SA of aquatic ecosystems which experience HABs. We present an overview of cyanotoxin fate in the environment, biological incorporation into SA, existing data on cyanotoxins in SA, relevant collection methods, and adverse health outcomes associated with cyanotoxin inhalation.

Reevaluation of the acute toxicity of palytoxin in mice: Determination of lethal dose 50 (LD50) and No-observed-adverse-effect level (NOAEL)

Palytoxin is an emergent toxin in Europe and one of the most toxic substances know to date. The toxin disrupts the physiological functioning of the Na⁺/K⁺-ATPase converting the enzyme in a permeant cation channel. Human intoxications by PLTX after consumption of contaminated fishery products are a serious health issue and can be fatal. Several reports have previously investigated the oral and intraperitoneal toxicity of PLTX in mice. However, in all cases short observation periods (24 and 48 h) after toxin administration were evaluated. In this work, single oral or intraperitoneal doses of PLTX were administered to healthy mice and surviving animals were followed up for 96 h. The data obtained here allowed us to calculate the oral and intraperitoneal lethal doses 50 (LD₅₀) which were in the range of the values previously described. Surprisingly, the oral NOAEL for PLTX was more than 10 times lower than that previously described, a fact that indicates the need for the reevaluation of the levels of the toxin in edible fishery products.

Oil Spills and Human Health: Contributions of the Gulf of Mexico Research Initiative

The Gulf of Mexico Research Initiative (GoMRI) was established in 2010 with $500 million in funding provided by British Petroleum over a 10-year period to support research on the impacts of the Deepwater Horizon oil spill and recovery. Contributions of the GoMRI program to date focused on human health are presented in more than 32 peer-reviewed papers published between 2011 and May 2019. Primary findings from review of these papers are (i) the large quantity of dispersants used in the oil cleanup have been associated with human health concerns, including through obesogenicity, toxicity, and illnesses from aerosolization of the agents; (ii) oil contamination has been associated with potential for increases in harmful algal blooms and numbers of pathogenic Vibrio bacteria in oil-impacted waters; and (iii) members of Gulf communities who are heavily reliant upon natural resources for their livelihoods were found to be vulnerable to high levels of life disruptions and institutional distrust. Positive correlations include a finding that a high level of community attachment was beneficial for recovery. Actions taken to improve disaster response and reduce stress-associated health effects could lessen negative impacts of similar disasters in the future. Furthermore, GoMRI has supported annual conferences beginning in 2013 at which informative human health-related presentations have been made. Based on this review, it is recommended that the Oil Pollution Act of 1990 be updated to include enhanced funding for oil spill impacts to human health.