Organic pollutants in the coastal marine environment off San Diego, California. 3. Using linear alkylbenzenes to trace sewage‐derived organic materials

Abstract

Abstract-Linear alkylbenzenes (LABs) were detected in the Point Loma Wastewater Treatment Plant (PLWTP) effluent, Tijuana River runoff, microlayer, water column particulates, and sediments collected off the coast of San Diego in 1994. The distributions of LABs in various media and sampling locations suggested that these compounds were essentially derived from domestic waste discharges. The PLWTP outfall is a major source for LAB inputs, while the Tijuana River runoff discharges much lower amounts of LABs. However, the contents of sewage-derived organics can be enhanced in the sea surface microlayer near the mouth of the Tijuana River. In addition, the I/E ratios indicated that 30-55% of the LABs were degraded in the water column particulates and sediments. Other processes (e.g., dilution, evaporation, bioaccumulation, etc.) may also be important in removing LABs from the discharge zone. Sewage-derived organic materials can be carried into remote areas via suspension of fine particulates.

Assessment of aquatic wastewater pollution in a highly industrialized zone with sediment linear alkylbenzenes

“…As a result of incomplete sulfonation, trace amounts of LABs (13%) remain in the final products and are discharged to aquatic systems along with surfactant wastewater [6]. Because of the widespread use of detergents, LABs have been detected ubiquitously in municipal wastewater effluents [6,7], wastewater-polluted areas [6,[8][9][10], and organisms near impacted points [11][12][13]. Due to high hydrophobicity (log K OW $7-10) [5], LABs tend to sorb strongly to particulate matter in wastewater and settle to the bottom sediment.…”

“…In addition, LABs have been seen under anaerobic conditions for more than 20 years [14,15]. Therefore, sedimentary LABs have often been employed as molecular markers of municipal wastewater impacts [10,16,17].…”

Tracking anthropogenic influences on the continental shelf of China with sedimentary linear alkylbenzenes (LABs)

“…Sample extraction and fractionation procedures used in the current study were detailed previously (Zeng et al, 1997). Briefly, each freeze-dried sample ($20 g) was spiked with the surrogate standard, and Soxhlet-extracted with 200 mL of dichloromethane and acetone (1:1 in volume) mixture for 48 h. The extract was concentrated, solvent-exchanged to hexane, and purified on a glass column filled with alumina/silica gel (1:2 in volume).…”

“…Linear alkylbenzenes (LABs) have been utilized as markers of domestic waste, as they are raw materials in manufacture of linear alkylbenzene sulfonates, a widely used anionic surfactant (Eganhouse et al, 1983), and may be disposed to the environment as residues (1-3%) of commercial detergents (Eganhouse et al, 1983;Chalaux et al, 1995;Zeng et al, 1997). In fact, LABs have been ubiquitously detected in various environmental matrices, such as sediment (Eganhouse et al, 1983;Ishiwatari et al, 1983;Zhang et al, 2012;Liu et al, 2013a), municipal wastewater effluent (Eganhouse et al, 1983;Peterman and Delfino, 1990), river runoff (Takada and Ishiwatari, 1987;Ni et al, 2008), and biota (Murray et al, 1991;Phillips et al, 2001;Tsutsumi et al, 2002).…”

Utility of soil linear alkylbenzenes to assess regional anthropogenic influences with special reference to atmospheric transport

“…The procedures of sample extraction and purification/fractionation used in the present study were detailed previously (Zeng et al, 1997;Ni et al, 2008). Briefly, freeze-dried soil samples (~25 g), loaded GF/F filters, and PUF plugs were spiked with the surrogate standard, and Soxhlet-extracted with 200 mL of a mixture of dichloromethane and acetone (1:1 in volume) for 48 h, separately.…”