Occurrence, distribution and risk assessment of phthalate esters in dust deposited in the outdoor environment of Yazd industrial park using Monte Carlo simulation.

In this study, the distribution of eight phthalate esters (PAEs), namely (dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), bis (2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP)) were examined across fifteen sampling stations in Yazd industrial Park. All the PAEs in dust deposited in the outdoor environment were analyzed using a Gas-mass chromatography (GC-MS/MS) device. Both probabilistic and deterministic approaches were utilized to assess the non-carcinogenic and carcinogenic health risks for adult occupational population groups. These risks were associated with three exposure pathways: inhalation, ingestion, and dermal exposure to six phthalates in the dust samples. The findings revealed, among the fifteen sampling stations, highest and lowest concentrations of the PAEs in dust deposited in the outdoor environment were observed in S8 and S6, with BEHP (326.21 ± 4.35) µg/g and DMP (0.00 ± 0.02) µg/g, respectively. The total hazard index (HI) values were below one in all samples, indicating that the combined non-carcinogenic health risk from exposure to phthalates via inhalation, ingestion, and dermal pathways is within acceptable levels in each studied area. The total cancer risk (CR) values for BBP across all exposure routes were consistently low, with magnitudes ranging from 10- x 10-15to 10 x 10-11. The order of cancer risk from phthalate exposure in outdoor environments was ingestion > dermal > inhalation. The sensitivity analysis (SA) results indicated that the influential parameters in the carcinogenic risk in adult occupational population groups were concentration for inhalation and dermal pathways, as well as ingestion rate for the ingestion pathway. The result of this study provides new insight in to PAEs pollution and risk assessments related to the dust deposited in the outdoor environment of industrial Park. Furthermore, this finding is beneficial to the controlling the exposure and promoting steps to reduce PAEs contamination and manage health in the industrial area.

Introducing heterotrophic iron ore bacteria as new candidates in promoting the recovery of e-waste strategic metals.

Electrical instruments are an integral part of human life resulting in a vast electronic waste generation (74.7 Mt by 2030), threatening human life and the environment due to its hazardous nature. Therefore, proper e-waste management is a necessity. Currently, bio-metallurgy is a sustainable process and an emerging research field. Simultaneous leaching of metals using two groups of indigenous heterotrophs and autotrophs was an exciting work done in this study. Bioleaching experiments using pre-adapted cultures were investigated at three e-waste densities: 5, 10, and 15 g/L. Statistical analysis was done using two-way ANOVA. Copper (93%), zinc (21.5%), and nickel (10.5%) had the highest recovery efficiencies. There was a significant difference between copper, nickel, tin, and zinc concentrations and the bacterial group (P < 0.05); Iron-oxidizing bacteria showed the most weight decrease and recovered 46-47% of total metals, mainly copper and nickel, while sulfur oxidizers were more capable of zinc leaching. The heterotrophs solubilized tin preferably and substantially decreased e-waste weight. Using heterotrophs alongside autotrophs is proposed to promote metal recovery.

Remediation of metals and plastic from e-waste by iron mine indigenous acidophilic bacteria.

The growing consumption of electrical and electronic equipment leads to high amounts of electronic waste (e-waste), which is now considered the fastest-growing waste stream at the national and international levels. As well as being a potential secondary resource due to its precious metals content, e-waste also contains strategic metals and plastics. For instance, mobile phones have about 25-55% plastic substances. A few studies have been performed to investigate the potential of indigenous bacteria in metals' bioleaching from the polluted environment. Heterotrophic bioleaching potential in acidic conditions had been preliminarily investigated. Two soil types of iron ore were considered the source of indigenous bacteria. Despite the acidophilic nature of the bacterial consortium, they continued their leaching activity regardless of alkaline conditions. Maximum biorecovery rate related to copper (4%) responding to the main soil, owing to the higher copper content of mobile phone waste. Chromium had the least recovery rate (⩽0.002%). Overall, the maximum metal recovery rate was 4.7%, achieved by tailing heterotrophs at an e-waste loading of 10 g l-1. Statistical analysis had shown that there was no significant difference between the metal recovery rates and soil type or even the solid-liquid ratio (p > 0.05). Although acidophilic indigenous heterotrophs could not be an appropriate alternative for a large amount of metal recovery process, they might have considerable potential in the bioremediation of e-waste plastic fractions and metals in low concentrations simultaneously.