Mixture risk assessment due to ingestion of arsenic, copper, and zinc from milkfish farmed in contaminated coastal areas

Evaluation of the Interaction-Based Hazard Index Formula Using Data on Four Trihalomethanes from U.S. EPA's Multiple-Purpose Design Study

The interaction-based hazard index (HIINT), a mixtures approach to characterizing toxicologic interactions, is demonstrated and evaluated by statistically analyzing data on four regulated trihalomethanes (THMs). These THMs were the subject of a multipurpose toxicology study specifically designed to evaluate the HIINT formula. This HIINT evaluation uses single, binary and quaternary mixture THM data. While this research is considered preliminary, the results provide insights on the application of HIINT when toxicology mixture data are available and on improvements to the method. The results for relative liver weight show the HIINT was generally not conservative but did adjust the additive hazard index (HI) in the correct direction, predicting greater than dose-additivity, as seen in the mixture data. For the liver serum enzyme endpoint alanine aminotransferase, the results were mixed, with some indices giving an estimated effective dose lower than the observed mixture effective dose and others higher; in general, the HIINT adjusted the HI in the correct direction, predicting less than dose-additivity. In addition, a methodological improvement was made in the calculation of maximum interaction magnitude. Suggested refinements to the HIINT included mixture-specific replacements for default parameter values and approaches for supplementing the usual qualitative discussions of uncertainty with numerical descriptions.

Determination of potential sources of heavy metals in patients with urothelial carcinoma in central Taiwan: a biomonitoring case-control study

The clarification of possible exposure sources of multiple metals to identify associations between metal doses and urothelial carcinoma (UC) risk is currently limited in the literature. We sought to identify the exposure sources of 10 metals (Vanadium, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, cadmium, and lead) using principal component analysis (PCA) and then linked various principal component (PC) scores with environmental characteristics, including smoking-related indices, PM2.5, and distance to the nearest bus station. In addition, urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and DNA hypomethylation markers (5-methyl-2'-deoxycytidine levels; %5-MedC) were investigated in combination with UC risks. We conducted this hospital-based case control study in 359 UC patients with histologically confirmed disease and 718 controls. All data were collected from face-to-face interviews and medical records. Approximately 6 mL blood was collected from participants for analysis of multiple heavy metal and DNA methylation in leukocyte DNA. Further, a 20 mL urine sample was collected to measure urinary cotinine and 8-OHdG levels. In addition, average values for PM2.5 for individual resident were calculated using the hybrid kriging/land-use regression model. In UC patients, significantly higher cobalt, nickel, copper, arsenic, and cadmium (μg/L) levels were observed in blood when compared with controls. Three PCs with eigenvalues > 1 accounted for 24.3, 15.8, and 10.7% of UC patients, and 26.9, 16.7, and 11.1% of controls, respectively. Environmental metal sources in major clusters were potentially associated with industrial activities and traffic emissions (PC1), smoking (PC2), and food consumption, including vitamin supplements (PC3). Multiple metal doses were linked with incremental urinary 8-OHdG and DNA hypomethylation biomarkers. For individuals with high PC1 and PC2 scores, both displayed an approximate 1.2-fold risk for UC with DNA hypomethylation.In conclusion, we provide a foundation for health education and risk communication strategies to limit metal exposure in environment, so that UC risks can be improved potentially.

A Pilot Survey of Potentially Hazardous Trace Elements in the Aquatic Environment Near a Coastal Coal-Fired Power Plant in Taiwan

BACKGROUND

A limited number of potentially hazardous trace elements were quantified in the aquatic environment near the world's second largest coal-fired power plant (CFPP) and the coal combustion residual (CCR) disposition sites in Central Taiwan. We postulated that contamination from specific trace elements would be present in the abovementioned aquatic environments.

METHODS

Cross-sectional sampling of trace elements was first performed between September 24, 2017 and October 3, 2017 outside the CFPP, in the effluent sampled from Changhua, a county south of metropolitan Taichung, and at the historical CCR disposal sites, using the intertidal zone surface seawater and the seawater in an oyster farm as controls. Aqueous samples were collected from 12 locations for analysis of 13 trace elements (Al, As, B, Cd, total Cr, Co, Fe, Pb, Mn, Se, Sr, Tl, and V). We used inductively coupled plasma (ICP) optical emission spectrometry to determine B and Fe levels, and ICP mass spectrometry for all other trace elements. The Spearman rank correlation coefficient (Rho) was calculated to examine the pairwise relation among the trace elements.

RESULTS

Al (50% of all samples), B (66.7%), Fe (25%), Mn (50%), Sr (8.3%), and V (25%) were identified as being above the Environmental Protection Agency (EPA) regulation limit. The oyster farm seawater had no concerns. Mn (96.4 μg/L) in the CFPP drainage effluent was 1.9-fold above the regulation limit. Fe, Mn, and V were detected from the cooling channel at 4379, 625, and 11.3 μg/L, respectively. The effluent and water from the areas surrounding the 2 CCR dump sites revealed similar magnitudes of trace element contamination. B is highly correlated with Sr (Rho = 0.94, 95% confidence interval [CI], 0.80-0.98). Meanwhile, Fe is highly correlated with Al (Rho = 0.77), Pb (Rho = 0.71), Co (Rho = 0.75), and V (Rho = 0.84).

CONCLUSIONS

The EPA must set an explicit regulation limit for aluminum, boron, iron, and strontium in the aquatic environment. This exploratory research will inform policymaking regarding certain trace elements that could potentially have an adverse impact on public health and wildlife.