Biogeochemical Approaches to Assess PAH Pollution in an Urban Waterway

Abstract

Biogeochemical approaches were applied to enhance the study on polycyclic aromatic hydrocarbon (PAH) pollution in an urban waterway. Chemical characterizations of PAHs in the studied area were identified, geochemical factors were revealed, and related mechanisms were discussed. It was found that, during summer, an early diagenetic process in the sediment could play a major role for the existence of high PAH concentrations, especially high molecular weight PAHs (≥ 4 rings), in the water column and sediment porewater. This effect could vary with tidal cycling, and higher PAH concentration in the water column would be expected during low tide. Other potential pollution sources were also evaluated in the studied creek. Results showed that pyrogenic sources dominated in the creek, generally. Nevertheless, petroleum products from a metal recycling plant could be an important point source to the waterway during wet weather. Comparing with previous studies in other waterways of the same watershed and published literature suggested that the limited toxicity to the ecosystem was only detected in sediments. More information needs to be collected during low tide for a more objective evaluation of PAH toxicity in the creek.

Multiresidue Determination of Six Pesticide Adjuvants in Characteristic Minor Crops Using QuEChERS Method and Gas Chromatography‐Mass Spectrometry

“…To date, several methods, including gas chromatography (GC),‐ gas chromatography‐mass spectrometry (GC‐MS),‐ and high performance liquid chromatography (HPLC),, have been developed for determining toluene, xylenes, DMF or DMSO in pharmaceuticals, cosmetics, food packaging, textile, architectural coating, urine, serum, water, and soil samples. However, the method for analyzing the six target pesticide adjuvants in characteristic minor crops has not been reported.…”

“…Sample pretreatment techniques that could concentrate trace analytes and prevent interferences is a key step in analytical procedure. Recently, several methods have been explored for the determination of the six target pesticide adjuvants, such as liquid‐liquid extraction (LLE),‐ headspace extraction (HS),, solid‐phase microextraction (SPME),,, and purge and trap (PT) ,. However, the traditional LLE using large volumes of toxic organic solvents is tedious, time consuming, and environmentally unfriendly.…”