This review compiles different analytical methods reported by the researchers studying heavy metal contents in seaweed samples from a variety of natural and commercial sources. Heavy metals in seaweed affect environmental health and human health due to seaweed’s role in the aquatic food chain and human consumption. The potential for heavy metal presence in seaweed is due to industrial pollution and other human activities. There is an ongoing demand for evaluation of the presence of nutritional as well as hazardous metals in raw and processed seaweeds. This review article will look at the importance and usage of seaweed, the importance of measuring heavy metals in seaweed, seaweed’s ability to absorb heavy metals, the health risks of consuming seaweed, and reported atomic spectroscopy-based heavy metal analysis methods in research on seaweed.

Modern agricultural activities and concentrated animal feeding operations (CAFOs) are two of the major sources of groundwater contamination that affect the quality of drinking water. Conventional water quality improvement methods include direct filtration, coagulation/settling treatment techniques, membrane-based systems, and absorption-based systems. However, to date, there are no efficient and cost-effective processes available for water treatment. This study developed an innovative nanotechnology-based technique to improve groundwater quality. Magnetic nanosponges (MNSs) were synthesized and characterized using two different magnetic nanoparticles along with polymeric coagulants. The efficiency of MNSs in removing pollutants in wastewater collected from local diary and swine CAFO lagoons was investigated. Standard water quality evaluation parameters, such as the total organic content (TOC), turbidity, total suspended solids (TSS), and biological oxygen demand (BOD), were measured prior to and after treatment with MNSs. The results demonstrate the potential of MNSs to improve the quality of groundwater and support the development of a cost-effective best management practice (BMP) that also employs traditional coagulants at CAFOs and other wastewater treatment plants.

Since the 1950s, plastic production has skyrocketed. Various environmental and human activities are leading to the formation and accumulation of microplastics (MPs) in aquatic and terrestrial ecosystems, causing detrimental effects on water, soil, plants, and living creatures. Wastewater treatment plants (WWTPs) are one of the primary MP management centers meant to check their entry into the natural systems. However, there are considerable limitations in effectively capturing, detecting, and characterizing these MPs in the inlet and outlet of WWTPs leading to “unaccounted MPs” that are eventually discharged into our ecosystems. In order to assess the holistic picture of the MPs’ distribution in the ecosystems, prevent the release of these omitted MPs into the environment, and formulate regulatory policies, it is vital to develop protocols that can be standardized across the globe to accurately detect and account for MPs in different sample types. This review will cover the details of current WWTP adoption procedures for MP management. Specifically, the following aspects are discussed: (i) several processes involved in the workflow of estimating MPs in the outlet of WWTPs; (ii) key limitations or challenges in each process that would increase the uncertainty in accurately estimating MPs; (iii) favorable recommendations that would lead to the standardization of protocols in the workflow and facilitate more accurate analysis of MPs; (iv) research opportunities to tackle the problem of ‘missing MPs’; and (v) future research directions for the efficient management of MPs. Considering the burgeoning research interest in the area of MPs, this work would help early scientists in understanding the current status in the field of MP analysis in the outlet of WWTPs.

As a cost-effective sorbent, modified biochar has received increasing attention for the removal of heavy metal contaminants. Among several chemical modification methods, introducing thiol functional groups onto the surface of biochar has been identified as an effective enhancement approach for the heavy metal sorption and removal capacity of this porous adsorbent material. In general, chemical impregnation is a widely used method to graft thiol groups onto the surface of carbon-based materials. However, limited comparative data are available on the efficacy of the present biochar thiolation methods. In this study, the biochar of nine different organic sources was modified by two frequently used agents with distinct thiolation mechanisms: 3-Mercaptopropyltrimethoxysilane (3-MPTS) and β-mercaptoethanol. In addition to chemical impregnation, the ball milling method, a simple and environmentally friendly alternative thiolation method, was also evaluated. A comprehensive structural characterization of the biochar samples was completed before and after thiolation. A higher concentration of sulfur on the surface of the biochar was achieved through thiolation with β-mercaptoethanol, in which the thiolation mechanism is performed through an esterification reaction with the carboxylic acid functional groups of the activated biochar. Chemical impregnation was found to be a more effective thiolating method than ball milling using the same thiolating agent.