Correlation Between Toxic Elements and Pesticide Residues in Medicinal Herbs Available in Pharmaceutical Market.

The use of medicinal plants for self-medication of minor health conditions has become a widespread practice in contemporary society. Few consumes, however, question the contamination of these products with toxic factors resulting from the planet's increasingly polluted environment. This paper presents the levels of five toxic elements (As, Cr, Pb, Cd, and Hg) and nine organochlorine pesticides (hexachlorobenzene (HCB), lindane, heptachor, aldrin, dieldrin, endrin, p,p'DDE, p,p'DDD, and p,p'DDT) in 14 brands of regularly consumed medicinal products in Romania. The toxic elements content was determined using energy-dispersive X-ray fluorescence (EDXRF) technique, and organochlorine pesticide residues (OPCs) were quantified using gas-chromatographic method, equipped with electron capture detector (GC-ECD). The results show that in the case of Cr, Cd, and Hg, the concentrations exceeded the limit values established by World Health Organisation (WHO) for raw herbal material. The higher level of OPCs (such as p,p'DDD, p,p'DDT, aldrin, and dieldrin) was found in the samples of Hypericum perforatum-St. John's wort, Crataegus monogyna-hawthorn, and Epilobium parviflorum-hoary willowherb. The correlations between the content of toxic elements and pesticides were determined by statistical analysis. Hierarchical clustering technique was used to detect natural grouping between the toxic elements and pesticides. For herb samples, four clusters were identified, the strongest correlated cluster consisting of Pb, HCB, Cr, and Hg. A further analysis within this cluster suggested that Cr levels are statistically different from the rest of the elements.

Assessment of the metal pollution in surface sediments of coastal Tasaul Lake (Romania).

Forty-three surface sediment samples were collected in September 2019 from Tasaul Lake (Black Sea coast, Romania) to examine the metal distribution patterns, assess the level of metal contamination, and identify the pollutant sources. The determined mean metal concentrations were as follows: Al 49,772 mg/kg, Zn 84.40 mg/kg, Cr 83.70 mg/kg, V 76.45 mg/kg, Ni 42.53 mg/kg, Cu 34.27 mg/kg, Pb 26.30 mg/kg, As 12.49 mg/kg, and Hg 0.06 mg/kg. The metals in the surface sediments of Tasaul Lake displayed moderate spatial variation, with higher metal concentrations mainly occurring in the south and southeast (As, Pb, and Hg), southwest (Cu and Zn), and west of the lake (Cr, Ni, and V). Heavy metal contamination in sediments is assessed using pollution indices such as enrichment factor, contamination factor, and pollution load index. The highest CFs and EFs were determined for As (moderate to high pollution), followed by Pb (low to moderate pollution). The Cu, Zn, and Hg pollution indices showed values corresponding to low pollution levels, while Ni, Cr, and V presented the lowest indices, suggesting unpolluted sediments. Multivariate statistical analyses were performed to identify the origin of the analyzed heavy metals. Cr was predominantly sourced from lithogenic components, Ni and V originated from both natural and anthropogenic sources, and As, Cu, Zn, Pb, and Hg showed mainly anthropogenic sources such as agricultural runoff, domestic and industrial wastewater discharges, and quarrying activities.

Environmental quality assessment of reservoirs impacted by Hg from chlor-alkali technologies: case study of a recovery.

Mercury (Hg) pollution legacy of chlor-alkali plants will be an important issue in the next decades with the planned phase out of Hg-based electrodes by 2025 within the Minamata convention. In such a context, the present study aimed to examine the extent of Hg contamination in the reservoirs surrounding the Oltchim plant and to evaluate the possible improvement of the environmental quality since the closure of its chlor-alkali unit. This plant is the largest chlor-alkali plant in Romania, which partly switched to Hg-free technology in 1999 and definitely stopped the use of Hg electrolysis in May 2012. Total Hg (THg) and methylmercury (CH3Hg) concentrations were found to decrease in the surface waters and sediments of the reservoirs receiving the effluents of the chlor-alkali platform since the closure of Hg units. Hence, calculated risk quotients (RQ) indicated no adverse effect of Hg for aquatic organisms from the ambient water exposure. RQ of Hg in sediments were mostly all higher than 1, showing important risks for benthic organisms. However, ecotoxicity testing of water and sediments suggest possible impact of other contaminants and their mixtures. Hg hotspots were found in soils around the platform with RQ values much higher than 1. Finally, THg and CH3Hg concentrations in fish were below the food safety limit set by the WHO, which contrasts with previous measurements made in 2007 revealing that 92 % of the studied fish were of high risk of consumption. Discontinuing the use of Hg electrodes greatly improved the surrounding environment of chlor-alkali plants within the following years and led to the decrease environmental exposure to Hg through fish consumption. However, sediment and soil still remained highly contaminated and problematic for the river reservoir management. The results of this ecological risk assessment study have important implications for the evaluation of the benefits as well as limits of the Minamata Convention implementation.