Human health risk from arsenical pesticide contaminated soils: a long-term greenhouse study

Health Risk Assessment Based on Source Identification of Heavy Metal(loid)s: A Case Study of Surface Water in the Lijiang River, China

In this study, 24 surface water samples were collected from the main trunk/tributary of the Lijiang River during the wet season (April) and the dry season (December) in 2021. The total concentration of 11 heavy metal(loid)s (Al, Cu, Pb, Zn, Cr, Ni, Co, Cd, Mn, As, and Hg) was determined to investigate their physicochemical properties and spatial-temporal distribution characteristics. The heavy metal evaluation index (HEI) and the positive matrix factorization (PMF) model were employed to evaluate water quality and to reveal quantitatively identified pollution sources for further investigation to obtain a health risk assessment using the hazard index (HI) and carcinogenic risk (CR) of various pollution sources. The mean concentrations of heavy metal(loid)s in surface water in the wet and dry seasons were ranked as: Al > Mn > Zn > Ni > Cd > Cr > Cu > As >Hg = Pb > Co, with the mean concentration of Hg being higher than the national Class II surface water environmental quality standard (GB3838-2002). In terms of time scale, the concentration of most heavy metal(loid)s was higher in the wet season; most heavy metal(loid)s were distributed mainly in the midstream area. HEI index indicated that the main water quality status was “slightly affected” in the study area. Five potential sources of pollution were obtained from the PMF model, including industrial activities, traffic sources, agricultural activities, domestic waste emissions, and natural resources. The source-oriented risk assessment indicated that the largest contributions of HI and CR were agricultural sources in the Lijiang River. This study provides a “target” for the precise control of pollution sources, which has a broad impact on improving the fine management of the water environment in the basin.

Alteration in soil arsenic dynamics and toxicity to sunflower (Helianthus annuus L.) in response to phosphorus in different textured soils

Being analogue to arsenic (As), phosphorus (P) may affect As dynamics in soil and toxicity to plants depending upon many soil and plant factors. Two sets of experiments were conducted to determine the effect of P on As fractionation in soils, its accumulation by plants and subsequent impact on growth, yield and physiological characteristics of sunflower (Helianthus annuus L.). Experimental plan comprised of two As levels (60 and 120 mg As kg^-1 soil), four P (0-5-10-20 g phosphate rock kg^-1 soil) and three textural types (sandy, loamy and clayey) with three replications. Among different As fractions determined, labile, calcium-bound, organic matter-bound and residual As increased while iron-bound and aluminum-bound As decreased with increasing P in all the three textural types. Labile-As percentage increased in the presence of P by 16.9-48.0% at As60 while 36.0-68.1% at As120 in sandy, 19.1-64.0% at As60 while 11.5-52.3% at As120 in loamy, and 21.8-58.2% at As60 while 22.3-70.0% at As120 in clayey soil compared to respective As treatment without P. Arsenic accumulation in plant tissues at both contamination levels declined with P addition as evidenced by lower bioconcentration factor. Phosphorus mitigated the As-induced oxidative stress expressed in term of reduced hydrogen peroxide, malondialdehyde while increased glutathione, and consequently improved the achene yield. Although, P increased As solubility in soil but restricted its translocation to plant, leading to reversal of oxidative damage, and improved sunflower growth and yield in all the three soil textural types, more profound effect at highest P level and in sandy texture.

Health risk assessment based on source identification of heavy metals: A case study of Beiyun River, China

Long-term retention and accumulation of heavy metals in rivers pose a great threat to the stability of ecosystems and human health. In this study, Beiyun River was taken as the example to quantitatively identify pollution sources and assess the pollution source-oriented health risk. A total of 8 heavy metals (Mn, Ni, Pb, Zn, As, Cr, Cd, and Cu) in Beiyun River were measured. Ordinary kriging (OK) and inverse distance weight (IDW) methods were used to predict the distribution of heavy metals. The results showed that the OK method is more accurate, and heavy metal pollution in the midstream and downstream is much more serious than that in the upstream. Principal component analysis-multiple linear regressions (PCA-MLR) and positive matrix factorization (PMF) methods were used to quantitatively identify pollution sources. The coefficient of determination (R²) of PMF is closer to 1, and the analyzed pollution source is more refined. Furthermore, the result of source identification was imported into the health risk assessment to calculate the hazard index (HI) and carcinogenic risk (CR) of various pollution sources. The results showed that the HI and CR of As and Ni to local residents were serious in the Beiyun River. Industrial activities (23.0%) are considered to be the largest contribution of heavy metals in Beiyun River, followed by traffic source (17%), agricultural source (16%), and atmospheric deposition (16%). The source-oriented risk assessment indicated that the largest contribution of HI and CR is agricultural source in the Beiyun River, followed by industrial activities. This study provides a "target" for the precise control of pollution sources, which is of great significance for improving the fine management of the water environment in the basin.

Plant Nanobionic Sensors for Arsenic Detection

Arsenic is a highly toxic heavy-metal pollutant which poses a significant health risk to humans and other ecosystems. In this work, the natural ability of wild-type plants to pre-concentrate and extract arsenic from the belowground environment is exploited to engineer plant nanobionic sensors for real-time arsenic detection. Near-infrared fluorescent nanosensors are specifically designed for sensitive and selective detection of arsenite. These optical nanosensors are embedded in plant tissues to non-destructively access and monitor the internal dynamics of arsenic taken up by the plants via the roots. The integration of optical nanosensors with living plants enables the conversion of plants into self-powered autosamplers of arsenic from their environment. Arsenite detection is demonstrated with three different plant species as nanobionic sensors. Based on an experimentally validated kinetic model, the nanobionic sensor could detect 0.6 and 0.2 ppb levels of arsenic after 7 and 14 days respectively by exploiting the natural ability of Pteris cretica ferns to hyperaccumulate and tolerate exceptionally high level of arsenic. The sensor readout could also be interfaced with portable electronics at a standoff distance, potentially enabling applications in environmental monitoring and agronomic research.

Design and synthesis of biopolymer-derived porous graphitic carbon covered iron-organic frameworks for depollution of arsenic from waters

A series of alginate-derived porous graphitic carbon (PGC) wrapped iron-based organic frameworks (Fe-MIL-88B) composites were synthesized and checked their ability for the removal of arsenite (As(III)) and arsenate (As(V)) from water. Various amounts of PGC (5, 10, 20, and 50 wt/wt %) were utilized as a wrapping material for the development of composites with Fe-MIL-88B@PGCx% and optimized for As(III)/As(V) adsorption. The chemical functionalities, structure, morphology, porous properties and bonding nature of the adsorbents were analyzed using FTIR, PXRD, SEM, BET, and XPS, respectively. Fe-MIL-88B@PGC20% composite was explored to have maximum removal efficiency and fastest adsorption kinetics for As(III)/As(V), of all Fe-MIL-88B@PGCx% composites and pristine Fe-MIL-88B studied here. The developed adsorbents are highly pH dependent and selective in common co-existing anions except for F^-, PO₄^3- and humic acid. The Langmuir isotherm studies of As(III) and As(V) adsorption suggest maximum adsorption capacities of 1.6853 and 2.2636 mmol/g, at pH of 3.0 and 9.2, respectively. The XPS analysis of As(III)-sorbed Fe-MIL-88B@PGC20% composite reveals that a portion of As(III) has been oxidized into As(V) during the adsorption process. The continuous flow-bed column study indicates that bed volumes of 249.6 and 452.8 mL of As(III) and As(V) contaminated water was treated, respectively, also reduced the concentration of As(III)/As(V) to less than WHO standards (<10 μg/L).

Arsenic fractionation and its impact on physiological behavior of sunflower (Helianthus annuus L.) in three texturally different soils under alkaline calcareous conditions

Soil textural composition may be important to control arsenic (As) behavior in soil and movement to plant. Two independent parallel experiments comprising of five As levels (0, 50, 100, 150, and 200 mg As kg^-1 soil) and three soil textural types (sandy, loamy, and clayey) were designed for determining As fractionation in soils and its consequential effects on growth, yield, and physiological characteristics of sunflower (Helianthus annuus L.). Six As fractions, i.e., NH₄Cl-extractable, NH₄F-extractable, NaOH-extractable, H₂SO₄-extractable, H₂O₂-extractable, and HNO₃-extractable, were determined. On an average, NH₄Cl-extractable As (the most phytoavailable among the extracted fractions) was 48.9, 19.8, and 6.6% of the total As while the bioaccumulation factor for root ranged between 1.9 and 9.5, 1.8 and 4.4, and 0.8 and 2.1 for sandy, loamy, and clayey textured soils, respectively. There was an increase of 8.3, 5.6, and 6.0 times in malondialdehyde with a subsequent reduction in photosynthetic rate by 53.3, 42.7, and 38.0% and achene yield 90.0, 87.1, and 85.5% in sandy, loamy, and clayey textured soils, respectively at 200 mg As kg^-1 as compared with the control. Antioxidant enzyme activities were increased with increasing As addition, and maximum activities were found at 150 mg As kg^-1, where catalase activities were 377.7, 341.6, and 292.0%; peroxidase 788.5, 758.6, and 737.0%; and superoxide dismutase 235.7, 191.8, and 177.2% higher in sandy, loamy, and clayey textured soils, respectively as compared with the control. In conclusion, As fractionation was markedly influenced by soil texture, and toxic effects of As on growth, yield and physiological characteristics of sunflower were maximum in sandy followed by loamy and clayey textured soils in descending order.

Prenatal epigenetics diets play protective roles against environmental pollution

It is thought that germ cells and preimplantation embryos during development are most susceptible to endogenous and exogenous environmental factors because the epigenome in those cells is undergoing dramatic elimination and reconstruction. Exposure to environmental factors such as nutrition, climate, stress, pathogens, toxins, and even social behavior during gametogenesis and early embryogenesis has been shown to influence disease susceptibility in the offspring. Early-life epigenetic modifications, which determine the expression of genetic information stored in the genome, are viewed as one of the general mechanisms linking prenatal exposure and phenotypic changes later in life. From atmospheric pollution, endocrine-disrupting chemicals to heavy metals, research increasingly suggests that environmental pollutions have already produced significant consequences on human health. Moreover, mounting evidence now links such pollution to relevant modification in the epigenome. The epigenetics diet, referring to a class of bioactive dietary compounds such as isothiocyanates in broccoli, genistein in soybean, resveratrol in grape, epigallocatechin-3-gallate in green tea, and ascorbic acid in fruits, has been shown to modify the epigenome leading to beneficial health outcomes. This review will primarily focus on the causes and consequences of prenatal environment pollution exposure on the epigenome, and the potential protective role of the epigenetics diet, which could play a central role in neutralizing epigenomic aberrations against environmental pollutions.

Detecting and Mapping Harmful Chemicals in Fruit and Vegetables Using Nanoparticle-Enhanced Laser-Induced Breakdown Spectroscopy

Residues of harmful chemicals in fruit and vegetables pose risks to human health. Ordinary laser-induced breakdown spectroscopy (LIBS) techniques are unsatisfactory for detecting harmful chemicals in fruit and vegetables. In this study, we applied metal nanoparticles to fruit and vegetables samples to improve the ability of LIBS to detect trace pesticide and heavy metal residues in the samples. The nanoparticle-enhanced LIBS technique gave pesticide residue detection limits for fruit and vegetables two orders of magnitude lower than achieved using standard LIBS and heavy metal detection limits markedly better than achieved using standard LIBS. We used the nanoparticle-enhanced LIBS technique to study the distributions of harmful chemicals in vegetable leaves. We found that heavy metals are distributed unevenly in edible plant leaves, the heavy metal concentrations being higher in the veins than in the mesophyll.

Evaluation and determination of soil remediation schemes using a modified AHP model and its application in a contaminated coking plant

Soil remediation has been considered as one of the most difficult pollution treatment tasks due to its high complexity in contaminants, geological conditions, usage, urgency, etc. The diversity in remediation technologies further makes quick selection of suitable remediation schemes much tougher even the site investigation has been done. Herein, a sustainable decision support hierarchical model has been developed to select, evaluate and determine preferred soil remediation schemes comprehensively based on modified analytic hierarchy process (MAHP). This MAHP method combines competence model and the Grubbs criteria with the conventional AHP. It not only considers the competence differences among experts in group decision, but also adjusts the big deviation caused by different experts' preference through sample analysis. This conversion allows the final remediation decision more reasonable. In this model, different evaluation criteria, including economic effect, environmental effect and technological effect, are employed to evaluate the integrated performance of remediation schemes followed by a strict computation using above MAHP. To confirm the feasibility of this developed model, it has been tested by a benzene workshop contaminated site in Beijing coking plant. Beyond soil remediation, this MAHP model would also be applied in other fields referring to multi-criteria group decision making.

Heavy metals (lead, cadmium, methylmercury, arsenic) in commonly imported rice grains (Oryza sativa) sold in Saudi Arabia and their potential health risk

The levels of heavy metals (lead, cadmium, methylmercury and arsenic) were determined in 37 brands of imported rice commonly consumed in Saudi Arabia after soaking and rinsing with water, and their potential health risks to residents were estimated by three indices: hazard quotient (HQ), hazard index (HI) and cancer risk (CR). The mean levels of lead, cadmium, methylmercury and total arsenic in soaked (rinsed) rice grains were 0.034 (0.057), 0.015 (0.027), 0.004 (0.007) and 0.202 (0.183) μg/g dry weight, respectively. Soaking or rinsing rice grains with water decreased lead and cadmium levels in all brands to safe levels. All brands had total arsenic above the acceptable regulatory limits, irrespective of soaking or rinsing, and eight soaked and 12 rinsed brands contained methylmercury. The levels of all heavy metals except cadmium were above the acceptable regulatory limits when the rice was neither rinsed nor soaked. Weekly intakes of lead, cadmium, methylmercury and total arsenic from soaked (rinsed) grains were 0.638 (1.068), 0.279 (0.503), 0.271 (0.309) and 3.769 (3.407) μg/kg body weight (bw). The weekly intakes of lead and methylmercury from the consumption of one rinsed and two soaked rice brands respectively, exceeded the Provisional Tolerance Weekly Intake set by the Food and Agriculture Organization and the World Health Organization. The weekly intake of total arsenic for all brands was above the lowest benchmark dose lower confidence limit (BMDL₀₁) level of 0.3μg/kg bw/d for an increased cancer risk set by European Food Safety Authority. Either soaking or rinsing grains before consumption can minimize the non-carcinogenic health risks to residents from cadmium and lead (HQ<1). Our local consumers, though, may experience health consequences from rice contaminated mainly with arsenic (HQ>1 all brands) and to a lesser extent with methylmercury (HQ>1 in 4 brands), even when soaked or rinsed with water before consumption. The combined non-carcinogenic effect of all metals expressed as HI was >1, including soaked or rinsed rice, with total arsenic the major contributor followed by methylmercury. CR for total arsenic, whether consuming soaked, rinsed, un-soaked or unrinsed grains, exceeded the acceptable level of 10^-4. Long-term consumption of rice contaminated with heavy metals, particularly arsenic, can pose potential health risks to the local population, especially vulnerable groups (pregnant women, children, elderly and patients). More attention should thus be given to contaminated rice and preventive measures should be taken.

Environmental exposure to arsenic and chromium in an industrial area

Arsenic and chromium are widespread environmental contaminants that affect global health due to their toxicity and carcinogenicity. To date, few studies have investigated exposure to arsenic and chromium in a population residing in a high-risk environmental area. The aim of this study is to evaluate the exposure to arsenic and chromium in the general population with no occupational exposure to these metals, resident in the industrial area of Taranto, Southern Italy, through biological monitoring techniques. We measured the levels of chromium, inorganic arsenic, and methylated metabolites, in the urine samples of 279 subjects residing in Taranto and neighboring areas. Qualified health staff administered a standardized structured questionnaire investigating lifestyle habits and controlling for confounding factors. The biological monitoring data showed high urinary concentrations of both the heavy metals investigated, particularly Cr. On this basis, it will be necessary to carry out an organized environmental monitoring program, taking into consideration all exposure routes so as to correlate the environmental concentrations of these metals with the biomonitoring results.

Non-occupational exposure to heavy metals of the residents of an industrial area and biomonitoring

In areas at high environmental risk, a major issue is the assessment of the exposure of the general population to industrial pollutants. To date, few studies have investigated exposure to heavy metals in a population residing in a high risk environmental area. The aim of this study is to evaluate the exposure to heavy metals in the industrial area of Taranto, Southern Italy, through biological monitoring techniques. We measured the levels of inorganic arsenic and methylated metabolites, lead, cadmium, chromium, and manganese in the urine samples of 279 subjects residing in Taranto and neighboring areas. After obtaining informed consent from each participant, qualified health staff administered a standardized structured questionnaire investigating lifestyle habits and assessing any confounding factors. The biological monitoring data showed high urinary concentrations of nearly all of the heavy metals investigated. These findings could be related to the presence of industrial plants and is sufficient to warrant the expectation that local and national institutions should be required to adopt preventive measures to reduce the environmental exposure of the general population to heavy metals.

Chronic Arsenic Poisoning Probably Caused by Arsenic-Based Pesticides: Findings from an Investigation Study of a Household

In addition to naturally occurring arsenic, man-made arsenic-based compounds are other sources of arsenic exposure. In 2013, our group identified 12 suspected arsenicosis patients in a household (32 living members). Of them, eight members were diagnosed with skin cancer. Interestingly, all of these patients had lived in the household prior to 1989. An investigation revealed that approximately 2 tons of arsenic-based pesticides had been previously placed near a well that had supplied drinking water to the family from 1973 to 1989. The current arsenic level in the well water was 620 μg/L. No other high arsenic wells were found near the family's residence. Based on these findings, it is possible to infer that the skin lesions exhibited by these family members were caused by long-term exposure to well water contaminated with arsenic-based pesticides. Additionally, biochemical analysis showed that the individuals exposed to arsenic had higher levels of aspartate aminotransferase and γ-glutamyl transpeptidase than those who were not exposed. These findings might indicate the presence of liver dysfunction in the arsenic-exposed individuals. This report elucidates the effects of arsenical compounds on the occurrence of high levels of arsenic in the environment and emphasizes the severe human health impact of arsenic exposure.