Determining toxicity of leachates from Florida municipal solid waste landfills using a battery‐of‐tests approach

Abstract

The toxicity and physicochemical parameters of municipal solid-waste (MSW) landfill leachates from six sites in north and north-central Florida, United States, were determined. Landfill leachates are complex mixtures of organic and inorganic constituents. Leachate toxicity was assayed using the acute C. dubia (48-h) and Microtoxtrade mark (15-min) assays and the chronic S. capricornutum (96-h) assay. The landfill leachates were shown to be highly toxic to both C. dubia and S. capricornutum with an EC(50) < 10% and < 15%, respectively. However, Microtoxtrade mark was not as sensitive to the leachates. Based on these results, the assays were ranked for their sensitivities to the landfill leachates; C. dubia > S. capricornutum > Microtoxtrade mark. Chemical analyses showed high concentrations of un-ionized ammonia and salts in the landfill leachates but low concentrations of heavy metals. The toxicity of the landfill leachates varied between the sites sampled and within each of the landfill sites. A significant relationship was found between the total ammonia content of the leachates and toxicity as determined by the C. dubia and S. capricornutum assays. Although the chemical constituents in Florida MSW landfill leachates may be more dilute, the toxicity of the leachates is equivalent to that from industrial waste landfills.

Bioassays for the Evaluation of Landfill Leachate Toxicity

“…Of interest was that the biologically treated leachate from the mixed Industrial-MSW site showed no toxicity to V. fischeri. Similar sensitivities were reported by Isidori et al (2003) and Ward et al (2002) when using V. fischeri as a test species. All these authors had different strength leachates and all showed low toxicities toward V. fischeri.…”

“…The decrease was from 4 to 1 toxicity units after 13 d of treatment with activated sludge. Ward et al (2002) concluded that C. dubia was the most sensitive test for bioassays landfill leachate samples from Florida. Ward et al (2002) formed a battery of tests with Microtox, S. capricornutum, and C. dubia.…”

“…Ward et al (2002) concluded that C. dubia was the most sensitive test for bioassays landfill leachate samples from Florida. Ward et al (2002) formed a battery of tests with Microtox, S. capricornutum, and C. dubia. A range of 10-33 TU was found, thus showing the high sensitivity of the test species to landfill leachate.…”

Seasonal alterations of landfill leachate composition and toxic potency in semi-arid regions

“…Although genotoxic and endocrine-disrupting components which could merely affect leachate toxic potency [67,68] were not investigated in the current study, the occurrence of seasonal alterations of leachate parameters, such as Cond, TDS, and N-derived parameters are significantly related with the observed toxic effects in all species tested, thus indicating the deleterious effects of leachate. Similar findings were also observed by other studies, concerning the important role of leachate physicochemical parameters in the enhancement of its toxicity [27,37,69,70]. In particular, Pablos et al [37] reported that NH 3 and COD could affect leachate toxicity, while Tatsi and Zouboulis [27] reported significant correlations among various leachate parameters, such as Cond, TDS, NH 3 , COD and BOD 5 with leachate strength and its toxic potential.…”

“…Nitrogen derived components, such as NH 4 -N, could be responsible for most of the leachate acute toxicity observed in different species, since there is evidence that high levels of NH 4 -N are able to mask the toxic effects of other leachate components [6,37,69]. According to the latter, the involvement of this parameter in the enhancement of leachate toxicity may become crucial [1,47].…”