Many pharmaceuticals and personal care products (PPCPs) are commonly found in biosolids and effluents from wastewater treatment plants. Land application of these biosolids and the reclamation of treated wastewater can transfer those PPCPs into the terrestrial and aquatic environments, giving rise to potential accumulation in plants. In this work, a greenhouse experiment was used to study the uptake of three pharmaceuticals (carbamazepine, diphenhydramine, and fluoxetine) and two personal care products (triclosan and triclocarban) by an agriculturally important species, soybean (Glycine max (L.) Merr.). Two treatments simulating biosolids application and wastewater irrigation were investigated. After growing for 60 and 110 days, plant tissues and soils were analyzed for target compounds. Carbamazepine, triclosan, and triclocarban were found to be concentrated in root tissues and translocated into above ground parts including beans, whereas accumulation and translocation for diphenhydramine and fluoxetine was limited. The uptake of selected compounds differed by treatment, with biosolids application resulting in higher plant concentrations, likely due to higher loading. However, compounds introduced by irrigation appeared to be more available for uptake and translocation. Degradation is the main mechanism for the dissipation of selected compounds in biosolids applied soils, and the presence of soybean plants had no significant effect on sorption. Data from two different harvests suggest that the uptake from soil to root and translocation from root to leaf may be rate limited for triclosan and triclocarban and metabolism may occur within the plant for carbamazepine.

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Soil organisms are useful for quantification of ecological impact of chemical contamination of soils. This study examined the effects of creosote (complex mixture of polycyclic aromatic hydrocarbons) on composition and abundance of soil invertebrates (nematodes, collembolans and mites) and decomposition processes. Thirty intact soil cores and adjacent litter samples were collected each of three times during the 1998 growing season from soil contaminated with creosote for 50 years. Each core was divided evenly into two subsamples. Abundance of nematodes (by family), Collembola (by family), mites (by Oribatida and others), total bacterial biomass, and active fungal biomass were quantified in the first subsample; soil properties including polycyclic aromatic hydrocarbon (PAH) concentration, organic carbon, pH, electrical conductivity (EC), bulk density, soil moisture and soil texture were measured in the second subsample. Creosote affected soil food webs and decomposition more by altering habitat of microinvertebrates and their prey, fungi and bacteria, than by direct toxicity. We hypothesize that nematodes were affected directly by PAH, more than collembolans or mites, because of their intimate contact with contaminated soil particles and permeable cuticles. Collembola and mites explained decomposition of 100% cellulose and mixed cellulose/lignin substrates better than nematodes because of their co-location in the litter layer. This is the first study to examine effects of PAH contamination on soil food webs and ecological processes.

Triclosan and triclocarban are antibacterial agents that are widely used in numerous personal care products. Limited information is available on their environmental behavior in soils and soils land applied with wastewaters and biosolids. In this study, laboratory experiments were performed to investigate their adsorption and degradation in soils. Both antibacterial agents adsorbed strongly to the sandy loam and silty clay soils with and without addition of biosolids, with distribution coefficients (K(d)) ranging from 178 to 264 L kg(-1) for triclosan and from 763 to 1187 L kg(-1) for triclocarban. Sorption of triclosan decreased with increase in soil pH from 4 to 8, whereas triclocarban sorption showed no effect within the tested pH range. Competitive sorption was observed when triclosan and triclocarban coexisted, but the cosolute effect was concentration dependent. Biosolids amendment increased the sorption of triclosan and triclocarban, likely due to the addition of soil organic matter, but displayed no significant effect on degradation.

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Laboratory experiments were conducted to investigate the sorption and degradation of six antibiotics including Ciprofloxacin (CIP), Tetracycline (TC), Doxycycline (DTC), Sulfamethazine (SMZ), Sulfamethoxazole (SMX) and Clindamycin (CLD) in an aerobically digested biosolid. In the sorption experiment, CIP, TC, and DTC sorbed strongly, followed by CLD, while SMZ and SMX were only weakly sorbed to particles. An adsorption/desorption hysteresis was observed for nearly all the antibiotics to some extent. In the degradation experiment, the elimination of antibiotics, except CIP for which no degradation was observed, was found primarily attributed to biological degradation. For the degradation of TC, DTC, and CLD, a stable phase was achieved after preliminary degradation. We hypothesize that the nondegradable residuals are nondesorbable portions of sorbed antibiotics. From the results, other than SMX, all tested antibiotics can potentially survive biosolids storage periods and can be introduced into the environment following biosolids land application.

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