Residues crawl-slab constructed

Tables III and IV show residue levels of chlordane and heptachlor in soils and air, respectively, from crawl-slab constructed houses built on clay soils. Soil residues of chlordane averaged 1545 ppm (15 samples) from the 0 to 10-cm depth and 861 ppm (five samples) from the 10 to 20 cm depth. Heptachlor levels for the upper and lower soil layers were, respectively 441 ppm (11 samples) and 314 ppm (two samples). As was seen in crawl-space dwelling on clay soils, residues of chlordane were highest in air of the crawl space...

When residues in crawl-space constructed houses were compared with those in houses built on a crawl-slab foundation, residues were equivalent in soils but higher in air samples of rooms. The average house size of the crawl-space constructed house was 135 m2 and an average of 533 L of diluted termiticide were applied. The average size of the crawl-slab constructed house was 172 m2 and an average 734 L of the emulsion were applied. It is possible that more termiticide was applied in a smaller area in the crawl-slab constructed houses than in crawl-space constructed ones which could produce the higher residue levels. 

Chlordane and Heptachlor Residues in Clay Soils from Crawl-Slab Constructed Houses ... 

Slab-constructed dwellings were treated prior to the foundation being poured, and soil samples could not be taken. The data for airborne concentrations of termiticides are shown in Table VI. No residues were detected in five of the houses sampled and although the average amount of termitlcide applied was greater than that applied to the crawl-space houses (613 L vs 574 L), average residues in air in the kitchen and bedroom were lower. Residues of chlordane and heptachlor in the kitchens averaged 2.3 and 0.7 pg/m and those for bedrooms were 2.6 and 0.5 pg/m, respectively. 

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