Non Detection Research Articles

Characterization of the Selective Recording of Workplace Exposure Measurements into OSHA's IMIS Databank.

The Integrated Management Information System (IMIS) is the largest multi-industry source of exposure results available in North America. In 2010, the Occupational Safety and Health Administration (OSHA) released the Chemical Exposure Health Data (CEHD) that contains analytical results of samples collected by OSHA inspectors. However, the two databanks only partially overlap, raising suspicion of bias in IMIS data. We investigated the factors associated with selective recording of CEHD results into the IMIS databank. This analysis was based on personal exposure measurements of 24 agents from 1984 to 2009. The association between nine variables (level of exposure coded as detected versus non-detected (ND), whether a sampling result was part of a panel of chemicals, duration of sampling, issuance of a citation, presence of other detected levels during the same inspection, year, OSHA region, amount of penalty, and establishment size) and a CEHD sampling result being reported in IMIS was analyzed using modified Poisson regression. A total of 461900 CEHD sampling results were examined. The proportion of CEHD sampling results recorded into IMIS was 38% (51% for detected and 28% for ND measurements). In the models, the detected sampling results were associated with a higher probability of recording into IMIS than ND sampling results, and this difference was similar for panel versus non-panel samples. Probability of recording remained constant from 1984 to 2009 for sampling results measured on panels but increased for sampling results of single determinations of an agent. Some OSHA regions had probability of recording two times higher than others. No other variables that we examined were associated with a CEHD sampling result being reported in IMIS. Our results indicate that the under-reporting of sampling results in IMIS is differential: ND results (especially those determined from the panels) seem less likely to be recorded in IMIS than other results. It is important to consider both IMIS and CEHD data in order to reduce bias in evaluation of exposures in workplaces inspected by OSHA.

Distribution of Organohalogen Compounds in Surface Water and Sediments of Major River Systems Across South Korea

In this study, we assessed the occurrence, levels, and distribution patterns of hexachlorocyclohexanes (α-, β-, and γ-HCHs), endosulfans (α- and β-endosulfan, and endosufan sulfate), polybrominated diphenyl ethers (PBDEs), and perfluorinated compounds (PFCs) in major water systems across South Korea. We studied water and sediment in four major rivers (Han, Nakdong, Keum, and Yeongsan Rivers), six smaller rivers, and four reservoirs in South Korea. Results showed that these organohalogen compounds were widely distributed throughout the country. Relatively high concentration of γ-HCH was observed at the downstream of the highly populated areas, which indicates the current use of lindane for medical purposes. High concentrations of PFCs and endosulfans in water might reflect the current input of PFCs to the water systems through the release from PFC-containing products and the recent extensive use of endosulfans for pest control. Concentrations of organohalogen compounds in water and sediment were in the range of ND (nondetectable)–1.16 ng/L (average ± standard deviation: 0.342 ± 0.308 ng/L) and ND–0.30 ng/g (0.063 ± 0.093 ng/g) for HCHs (α-, β-, and γ-HCHs), 1.66–15.8 ng/L (6.36 ± 3.23 ng/L) and ND–6.85 ng/g (1.99 ng/g ± 1.04 ng/g) for endosulfans (α- and β-endosulfan, and endosufan sulfate), 0.019 ng/L–0.216 ng/L (0.097 ± 0.060 ng/L) and 0.091–12.13 ng/g (3.11 ± 4.21 ng/g) for 17 PBDEs, and ND–69.02 ng/L (14.06 ± 19.44 ng/L) and ND–3.715 ng/g (0.68 ± 1.16 ng/g) for PFCs (PFOA and PFOS), respectively. Different distribution of these POPs was observed between water and sediment even in the same locations, which might be due to the characteristics of continuously changing river water and stationary sediment as well as the different physicochemical properties of the POPs.

Polychlorinated naphthalenes (PCNs) in seafood: Estimation of dietary intake in Korean population

Polychlorinated naphthalenes (PCNs) were measured in 33 seafood species including fish, mollusks and crustaceans purchased from local markets in five Korean cities between 2012 and 2013. Five samples were collected from each species for the measurements. Thirty-seven PCN congeners from tetra-CN to octa-CN were measured. Octa-CN (octachloronaphthalene) was not detected in any of the samples. Tetra-CN and penta-CN were the predominant homologues of PCNs in seafood samples with PCN 51 and PCN 52/60 being the most abundant congeners in the samples. Total PCNs concentrations and their corresponding dioxin-like toxic equivalent (TEQ) values ranged from non-detection (ND) to 110pg/g on a wet weight (ww) basis and from ND to 0.14pg-TEQ/g ww, respectively. The estimated daily intake of total PCNs based on an absolute content and TEQ potency were estimated for the Koreans to be 570pg/day and 0.44pg-TEQ/day, respectively. However, the estimated TEQ value of PCNs intake from seafood, represented only a small fraction (3.0%) of the total TEQ intake from consumption of seafood in Korean population. This is the first report to exhibit the presence of PCNs in seafood samples collected from local markets in Korea and their intake by general population.

Contamination Characteristics and Human Exposure to Organophosphate Flame Retardants in Road Dust from Suzhou City

The contamination levels and distribution characteristics of four organophosphate flame retardants (OPFRs) in 25 outdoor dust samples collected in Suzhou were quantitatively analyzed by gas chromatography-mass spectrometry (GC-MS). The exposure to OPFRs via ingestion and inhalation of dust were also estimated for adults, children, and professional street sweepers. Four types of OPFRs were detected in all dust samples at different levels; the total OPFRs concentrations ranged from non-detected (ND) to 8901.66 ng·g-1, with a median of 1039.21 ng·g-1. The concentrations of TCPP, TBEP, TDCPP, and TCEP were in the range of 0-6931.46, 0-2021.15, 0-788.44, and 0-62.16 ng·g-1, respectively. The daily intake of ∑OPEs under a high dust ingestion scenario was 125.68, 915.78, and 6314.16 pg·kg-1 for adults, children, and professional street sweepers, respectively. The estimated exposure of children to ∑OPEs was six times higher than that of adults. However, the daily intake of OPFRs via dust inhalation was 3.07E-02, 1.89E-02, and 1.54E-01 pg·kg-1 for adults, children, and professional street sweepers, respectively. These findings indicated that the occurrence of OPFRs in the dust poses a significant risk to children and professional street sweepers.

Challenges of soil mixing using catalyzed hydrogen peroxide with rotating dual axis blending technology

AbstractAlthough known to be one of the most effective oxidants for treatment of organic contaminants, catalyzed hydrogen peroxide (CHP) is typically not used for soil mixing applications because of health and safety concerns related to vapor generation and very rapid rates of reaction in open excavations. In likely the first large‐scale in situ CHP soil mixing application, an enhanced CHP, modified Fenton's reagent (MFR), was applied during soil mixing at the Kearsarge Metallurgical Superfund Site in New Hampshire. An innovative rotating dual‐axis blender (DAB) technology was used to safely mix the MFR into low‐plasticity silt and clay soils to remediate residual 1,1,1‐trichloroethane (111TCA); 1,1‐dichloroethene (11DCE); and 1,4‐dioxane (14D). It was expected that the aggressive treatment approach using relatively “greener” hydrogen peroxide (HP) chemistry would effectively treat Site contaminants without significant byproduct impacts to groundwater or the adjacent pond. The remediation program was designed to treat approximately 3,000 cubic yards of residual source area soil in situ by aggressively mixing MFR into the soils. The subsurface interval treated was from 7 to 15 feet below ground surface. To accurately track the soil mixing process and MFR addition, the Site was divided into 109 10‐foot square treatment cells that were precisely located, dosed, and mixed using the DAB equipped with an on‐board GPS system. The use of stabilizing agents along with careful calculation of the peroxide dose helped to ensure vapor‐free conditions in the vicinity of the soil mixing operation. Real‐time sampling and monitoring were critical in identifying any posttreatment exceedences of the cleanup goals. This allowed retreatment and supplemental testing to occur without impacting the soil mixing/in situ chemical oxidation (ISCO) schedule. Posttreatment 24‐hr soil samples were collected from 56 random locations after ensuring that the HP had been completely consumed. The posttreatment test results showed that 111TCA and 11DCE concentrations were reduced to nondetect (ND) or below the cleanup goals of 150 μg/kg for 111TCA and 60 μg/kg for 11DCE. Supplemental posttreatment soil samples, collected six months after treatment, showed 100 percent compliance with the soil treatment goals. Groundwater samples collected one year after the MFR soil mixing treatment program showed either ND or low concentrations for 111TCA, 11DCE, and 14D. Successful stabilization and site restoration was performed after overcoming considerable challenges associated with loss of soil structure, high liquid content, and reduced bearing capacity of the blended soils.

Microplastics in a freshwater environment receiving treated wastewater effluent.

Small plastic fragments (microplastics or solid particles <5 mm in size or "microbeads" used in personal care products and cosmetics) may ultimately find their way into aquatic environments. We studied the presence of microplastics (particle sizes 53-105 μm and 106-179 μm) spatially and temporally in 3 connected urban lakes being fed by treated wastewater effluent in Lubbock, Texas. These lakes also serve as drainage during storm events. Water samples from drainage playa wetlands within the city were also collected. Our interest was in determining the presence or absence of microplastics in a freshwater environment as well as the source apportionment between personal care products (via wastewater) and discarded plastics (via runoff). Results showed that average concentrations of microplastics in samples collected from lakes ranged from 0.79 ± 0.88 mg/L to 1.56 ± 1.64 mg/L for the 53-105 μm size fraction and from 0.31 ± 0.72 mg/L to 1.25 ± 1.98 mg/L for the 106-179 μm size fraction. For samples collected from playa wetlands, average microplastic concentrations ranged from 0.64 ± 0.92 mg/L to 5.51 ± 9.09 mg/L for the 53-105 μm size fraction and from nondetectable (ND) to 1.79 ± 3.04 mg/L for the 106-179 μm size fraction. Our results (based on comparison of microplastic masses) suggest that urban runoff also contributes microplastics to surface water in addition to the treated wastewater effluent (in this particular case). The present findings may assist in adopting additional monitoring efforts and provide information on the potential contribution of secondary microplastic input into aquatic environments. Integr Environ Assess Manag 2017;13:528-532. © 2017 SETAC.

Diversity and activity of methanotrophic related bacteria in subsurface sediments of the Krishna-Godavari Basin, India

The present study assesses the distribution, diversity and activity of aerobic methanotrophic related bacteria (MRB) dwelling in Krishna-Godavari (KG) basin, India. The counts of MRB ranged from non-detectable (ND) to 8.6 × 10 4 CFU gram dry weight of the sediment, with maximum counts at 24.2 m below seafloor. Greater methanotrophic bacterial abundance was at the surface/subsurface sediments of the core at station MD161-8 than at the bottom sediments. Identification of these isolates by 16S rDNA sequence analysis showed their taxonomic affiliation to Alcanivorax, Methylophaga, Marinobacter, Joostella, Methylobacterium, Desulfovibrio species and other uncultured bacterial clones. The isolates grew under optimum pH of 8, temperature of 28°C and salinity of 35, and on different carbon sources like yeast extract, D-glucose, ethanol and methanol. The addition of nitrogen sources like amino acids and yeast extract improved methanotrophic activity by the isolates. These results add to our understanding of MRB and their activity in modulating the emission of methane from gas hydraterich ecosystems like the KG basin.

Influence of non-detect data-handling on toxic equivalency quantities of PCDD/Fs and dioxin-like PCBs: A case study of major fish species purchased in Korea

It has been known that substitution is not a suitable method to address non-detect (ND) data and can result in significant errors. However, reports of reliable statistical methods for handling ND data of polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in fish are rare. This work examines US-EPA's recommended statistical methods and traditional substitution-based methods for handling ND data in PCDD/F and DL-PCB datasets obtained from 240 fish samples. The Kaplan-Meier (KM) method was confirmed as a suitable statistical approach for dealing with our fish datasets. The results of the KM and substitution methods were compared; a significant difference was found in TEQs derived from KM and substitution for PCDD/Fs, suggesting that the handling of ND data is a critical issue for PCDD/Fs. For example, the substitution by ½LOD resulted in 20–25% overestimation of PCDD/F TEQs for fish samples with ND data (60–70%). In conclusion, the use of KM method is preferable for average TEQs, and if the use of KM is not applicable, substitution by zero is preferred. Based on this conclusion, the characteristics of fish contamination by PCDD/Fs and DL-PCBs in Korea were investigated.

Study on disinfection by-products formation according to kind of salt in on-site production

Although disinfection in drinking water treatment plants provides a safer water supply by inactivating pathogenic microorganisms, harmful disinfection by-products may be formed. In this study, the disinfectant, chlorine, was produced on-site from the electrolysis of salt (NaCl), and the by-products of the disinfection process, bromate and chlorate, were analyzed. The provisional guideline levels for bromate and chlorate in drinking water are and , in Korea, respectively. Bromide salt was detected at concentrations ranging from 6.0 ~ 622 mg/kg. Bromate and chlorate were detected at concentrations ranging from non-detect (ND) ~ 45.3mg/L and 40.5 ~ 1,202 mg/L, respectively. When comparing the bromide concentration in the salt to the bromate concentration in the chlorine produced by salt electrolysis, the correlation of bromide to bromate concentration was 0.870 (active chlorine concentration from on-site production: 0.6-0.8%, n=40). The correlation of bromate concentration in the chlorine produced to that in the treated water was 0.866.

Manganese Fractionation Using a Sequential Extraction Method to Evaluate Welders’ Shielded Metal Arc Welding Exposures During Construction Projects in Oil Refineries

The National Institute for Occupational Safety and Health has conducted an occupational exposure assessment study of manganese (Mn) in welding fume of construction workers rebuilding tanks, piping, and process equipment at two oil refineries. The objective of this study was to evaluate exposures to different Mn fractions using a sequential extraction procedure. Seventy-two worker-days were monitored for either total or respirable Mn during stick welding and associated activities both within and outside of confined spaces. The samples were analyzed using an experimental method to separate different Mn fractions by valence states based on selective chemical solubility. The full-shift total particulate Mn time-weighted average (TWA) breathing zone concentrations ranged from 0.013–29 for soluble Mn in a mild ammonium acetate solution; from 0.26–250 for Mn0,2+ in acetic acid; from non-detectable (ND) – 350 for Mn3+,4+ in hydroxylamine-hydrochloride; and from ND – 39 micrograms per cubic meter (μg/m3) for insoluble Mn fractions in hydrochloric and nitric acid. The summation of all Mn fractions in total particulate TWA ranged from 0.52–470 μg/m3. The range of respirable particulate Mn TWA concentrations were from 0.20–28 for soluble Mn; from 1.4–270 for Mn0,2+; from 0.49–150 for Mn3+,4+; from ND – 100 for insoluble Mn; and from 2.0–490 μg/m3 for Mn (sum of fractions). For all jobs combined, total particulate TWA GM concentrations of the Mn(sum) were 99 (GSD = 3.35) and 8.7 (GSD = 3.54) μg/m3 for workers inside and outside of confined spaces; respirable Mn also showed much higher levels for welders within confined spaces. Regardless of particle size and confined space work status, Mn0,2+ fraction was the most abundant followed by Mn3+,4+ fraction, typically >50% and ∼30–40% of Mn(sum), respectively. Eighteen welders’ exposures exceeded the ACGIH Threshold Limit Values for total Mn (100 μg/m3) and 25 exceeded the recently adopted respirable Mn TLV (20 μg/m3). This study shows that a welding fume exposure control and management program is warranted, especially for welding jobs in confined spaces.

국내에서 소비되는 상용 식품의 비타민 K1함량 분석

Vitamin K1 (phylloquinone) content of commonly consumed foods in Korea were determined by solvent extraction followed by reversed-phase liquid chromatography using post-column derivatization and fluorescence detection. Samples were obtained in the years of 2013 and 2015. In this study, 46 vegetables, 14 fruits, and 6 legumes were analyzed. Relatively higher amounts of vitamin K1 were found in sweet potato leaves, green kiwi, and mung beans among vegetables, fruits, and legumes, respectively. The content of vitamin K1 in vegetables including spinach, broccoli, and potato ranged from non-detectable (ND) to 1,467.3 μg/100 g. The content of vitamin K1 in fruits ranged from ND to 42.7 μg/100 g. The content of vitamin K1 in legumes, including soybeans, mung beans and peas ranged from 1.7 to 63.4 μg/100 g. In addition, the analytical method validation parameters including recovery, reproducibility, repeatability, peak purity, and linearity were calculated to ensure the method's validity. The results showed high linearity with a correlation coefficient of 0.9999. Overall recovery was close to 100% (n=5). This study revealed reliable vitamin K content in commonly consumed foods in Korea for a nutritional information and food composition database.

Legacy and emerging halogenated organic pollutants in marine organisms from the Pearl River Estuary, South China

A suite of legacy and emerging halogenated organic pollutants (HOPs) were measured in marine organisms (coastal fish and invertebrates) from the Pearl River Estuary, South China, to investigate the current contamination status after the Stockholm Convention was implemented in China. Dichlorodiphenyltrichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were detected in all samples at concentrations of 54–1500, 16–700, and 0.56–59ng/g lipid weight, respectively. Dechlorane Plus (DP), decabromodiphenyl ethane (DBDPE), 2,3,5,6-tetrabromo-p-xylene (pTBX), and pentabromotoluene (PBT) were also found at concentrations of ND (non-detectable) to 37ng/g lipid weight. The concentrations of these investigated contaminants in the present study were at moderate levels, as compared with those reported in other regions. Significant interspecies differences were found in the levels of DDTs, PCBs, PBDEs and the alternative halogenated flame retardants (AHFRs). DDTs were the predominant HOPs in those species and represented >50% of the total HOPs, followed by PCBs, PBDEs, and AHFRs. The total estimated daily intakes (EDIs) of DDTs, PCBs, PBDEs, and AHFRs were 28, 12, 1.0, and 0.18 (ng/kg)/d, respectively, via seafood consumption. These concentrations are not expected to pose health risks to humans.

Spatial Distribution of Methanesulphonic Acid in the Arctic Aerosol Collected during the Chinese Arctic Research Expedition

Methanesulphonic acid (MSA, mainly derived from marine biogenic emissions) has been frequently used to estimate the marine biogenic contribution. However, there are few reports on MSA over the Arctic Ocean, especially the central Arctic Ocean. Here, we analyzed MSA in aerosol samples collected over the ocean and seas during the Chinese Arctic Research Expedition (CHINARE 2012) using ion chromatography. The aerosol MSA concentrations over the Arctic Ocean varied considerably and ranged from non-detectable (ND) to 229 ng/m3, with an average of 27 ± 54 ng/m3 (median: 10 ng/m3). We found the distribution of aerosol MSA exhibited an obvious regional variation, which was affected by biotic and abiotic factors. High values were generally observed in the Norwegian Sea; this phenomenon was attributed to high rates of phytoplankton primary productivity and dimethylsulfide (DMS) fluxes in this region. Concentrations over the pack ice region in the central Arctic Ocean were generally lower than over the open waters at the ice edge in the Chukchi Sea. This difference was the mainly caused by sea ice. In addition, we found that higher MSA concentrations were associated with warmer sea surface temperature (SST).

Levels of perfluorinated compounds in human breast milk in Jordan: the impact of sociodemographic characteristics.

There is scarcity in literature in regards to the exact levels of such compounds in the Middle Eastern region including Jordan. This study was conducted to measure the presence and levels of perfluoroalkyl substances (PFASs) (perfluoroocane sulfonate (PFOS) and perfluorooctanoic acid (PFOA)) in human milk and local fresh cow milk in northern Jordan and also to investigate the relationship between levels of PFASs and some sociodemographic characteristics of breastfeeding mothers and their infants as well as usage of Teflon kitchenware products. Seventy-nine milk samples were collected from breastfeeding women and 25 samples from local fresh cow milk in northern Jordan. Levels of PFOS and PFOA were liquid/liquid extracted (LLE) by acetone followed by purification on an Oasis hydrophilic-lipophilic balance (HLB) solid-phase extraction (SPE). Separations and detections were performed by liquid chromatography-tandem mass spectrometry. Limits of quantitation (LOQs) were 10 ng/L for both PFOA and PFOS. The measured concentrations ranged between non-detectable (ND) and 178 ng/L for PFOS and between 24 and 1120 ng/L for PFOA in human milk and between ND-178 ng/L and LOQ-160 ng/L in fresh cow milk, respectively. Median concentrations of PFOS in human milk samples from Jordan in this study were lower than those found in a recent study from Italy. Moreover, mean concentrations of PFOA and PFOS were significantly higher in milk samples provided by older women. Also, mean concentrations of PFOA was much higher in multiparas and those who have younger infants. The mean rank of PFOA was twice as high in the milk of women who had older Teflon products in kitchen compared to those who had relatively new Teflon products.

Application of a portable infrared instrument for simultaneous analysis of sugars, asparagine and glutamine levels in raw potato tubers.

The level of reducing sugars and asparagine in raw potatoes is critical for potato breeders and the food industry for production of commonly consumed food products including potato chips and French fries. Our objective was to evaluate the use of a portable infrared instrument for the rapid quantitation of major sugars and amino acids in raw potato tubers using single-bounce attenuated total reflectance (ATR) and dial path accessories as an alternative to time-consuming chromatographic techniques. Samples representing a total of 84 experimental and commercial potato varieties harvested in two consecutive growing seasons (2012 and 2013) were used in this study. Samples had wide ranges of sugars determined by HPLC-RID (non-detectable (ND)-7.7mg glucose, ND-9.4mg fructose and 0.4-5.4mg sucrose per 1g fresh weight), and asparagine and glutamine levels determined by GC-FID (0.7-2.9mg and 0.3-1.7mg per 1g fresh weight). Infrared spectra collected from 64 varieties were used to create partial least squares regression (PLSR) calibration models that predicted the sugar and amino acid levels in an independent set of 16 validation potato varieties. Excellent linear correlations between infrared predicted and reference values were obtained. PLSR models had a high correlation coefficient of prediction (rPred >0.95) and residual predictive deviation (RPD) values ranging between 3.1 and 5.5. Overall, the results indicated that the models could be used to simultaneously predict sugars, free asparagine and glutamine levels in the raw tubers, significantly benefiting potato breeding, certain aspects of crop management, crop production and research.

Total petroleum hydrocarbons in sediments from the coastline and mangroves of the northern Persian Gulf

To provide baseline information for the marine ecosystem of Hormozgan province, the distribution of petroleum hydrocarbons was evaluated in 52 stations involved in the mangrove and coastline ecosystem. Coastline sampling sites included areas facing harbor, river, domestic and industrial discharge. Sediment samples were analyzed based on ultraviolet fluorescence spectroscopy. Petroleum hydrocarbons showed narrow variations ranging from non-detectable (ND) to 1.71 and from 0.2 to 0.63μg/g dry weight for coastline and mangrove sediments, respectively. The detected concentrations for total petroleum hydrocarbons were lower than guideline values for ecological risk. Furthermore, the minimum environmental risk was confirmed by background levels for the Persian Gulf, the Sea of Oman, and detected values for reference areas. The results were regarded as background data in the studied area, and, considering the rapid expansion of activities related to the petroleum industry in Hormozgan province, the continuous monitoring of pollutants is recommended.

FDG PET/CT imaging in prostate adenocarcinoma presenting as isolated brain metastases of unknown origin

In this study, we monitored the newly added Stockholm Convention persistent organic pollutants (POPs) HCHs, PeCBz, endosulfans, chlordecone, PBDEs, PBBs and PFCs in industrial, urban, and agricultural soils in South Korea, in order to evaluate their distributions and potential sources. These POPs were widely distributed throughout South Korea, and their concentrations and distributions were affected by land use, reflecting their sources. The overall concentrations of HCHs, PeCBz, endosulfans, PBDEs, and PFCs in soils were in the range of ND (non-detectable)–0.358 ng/g (average ± standard deviation: 0.060 ± 0.080 ng/g), ND–0.531 ng/g (0.083 ± 0.133 ng/g), 0.058–8.42 ng/g (2.19 ± 2.43 ng/g), 0.004–4.78 ng/g (0.68 ± 1.06 ng/g), and ND–1.62 ng/g (0.50 ± 0.46 ng/g), respectively. Agricultural soils showed the highest concentration of endosulfan, which was the most recently used pesticide monitored in this study. On the other hand, industrial soils contained the highest concentrations of PeCBz, PBDEs, and PFCs, which were mainly introduced to environment via the industrial activities.

Prediction of paralytic shellfish toxin based on a projected future climate scenario for South Korea

This study aimed to predict the seasonal patterns of paralytic shellfish poison (PSP) level in the next 90years based on a future climate scenario, Representative Concentration Pathway (RCP) 8.5. To achieve this goal, we constructed a censored regression model using seawater temperature, weekly change in seawater temperature, salinity, rainfall, insolation, shell species, and areas prone to red tide as potentially influential environmental factors on PSP level in the coastal areas of South Korea. The censored regression model is used instead of the ordinary regression model because the PSP data had a large portion of non-detectable (ND) data. All of the continuous environmental covariates had significant quadratic relationships with the PSP toxin level except insolation. These results indicated that there are favorable ranges of seawater temperature, weekly change in seawater temperature, salinity, and rainfall to PSP production. To predict the future PSP distribution, we plugged the environmental condition data under a future climate scenario, RCP 8.5 scenario, in the estimated regression model. In the future, it is expected that the highest frequency of shellfish poisoning outbreaks will occur during the earlier months in the year, such as February and March, whereas most outbreaks of shellfish poisoning have occurred in April and May during recent years in South Korea.

Human health risk assessment with spatial analysis: Study of a population chronically exposed to arsenic through drinking water from Argentina

Arsenic (As) is a ubiquitous element widely distributed in the environment. This metalloid has proven carcinogenic action in man.The aim of this work was to assess the health risk related to As exposure through drinking water in an Argentinean population, applying spatial analytical techniques in addition to conventional approaches. The study involved 650 inhabitants from Chaco and Santiago del Estero provinces. Arsenic in drinking water (Asw) and urine (UAs) was measured by hydride generation atomic absorption spectrophotometry. Average daily dose (ADD), hazard quotient (HQ), and carcinogenic risk (CR) were estimated, geo-referenced and integrated with demographical data by a health composite index (HI) applying geographic information system (GIS) analysis. Asw covered a wide range of concentration: from non-detectable (ND) to 2000μg/L. More than 90% of the population was exposed to As, with UAs levels above the intervention level of 100μg/g creatinine.GIS analysis described an expected level of exposure lower than the observed, indicating possible additional source/s of exposure to inorganic arsenic.In 68% of the locations, the population had a HQ greater than 1, and the CR ranged between 5·10−5 and 2,1·10−2. An environmental exposure area through ADD geo-referencing defined a baseline scenario for space-time risk assessment.The time of residence, the demographic density and the potential health considered outcomes helped characterize the health risk in the region. The geospatial analysis contributed to delimitate and analyze the change tendencies of risk in the region, broadening the scopes of the results for a decision-making process.

Insecticide residues in soil and water in coastal areas of vegetable production in Togo.

Some common organochlorine, organophosphorus and pyrethroid insecticides were analysed in agricultural soil samples (n = 35) and surface water and groundwater samples (n = 25) collected from coastal areas of vegetable production in Togo. Analytical methods included solvent extraction of the insecticide residues and their subsequent quantification using GC-ECD. δ-HCH, heptachlor epoxide, 4,4-DDE, endosulphan (α, β and sulphate), lambda-cyalothrin and chlorpyrifos were found in the soil samples with concentrations that varied from non-detectable (ND) to 26.93μgkg(-1) dry weight. For water samples, heptachlor epoxide, 2,4-DDD, 4,4-DDD, 4,4-DDE and endosulphan (α, β, and sulphate) were found at contamination levels that varied from ND to 0.116μgL(-1). The concentration of insecticide residues detected in the water samples was below the limits set by the World Health Organization (WHO) and also by the European Union (EU), with the exception of the concentration of endosulphan sulphate at the Aného site, which was 0.116μgL(-1).