A pilot simulation study of arsenic tracked from CCA-treated decks onto carpets.

A controlled simulation experiment was performed to assess whether dislodgeable arsenic can be tracked onto carpets via foot traffic from chromated copper arsenate (CCA) pressure-treated decks. The pilot simulation study demonstrated that it is possible to track arsenic from CCA-decks onto carpets under the test conditions evaluated. A total of nine CCA-decks and two non-CCA-treated control surfaces were tested under wet and dry conditions. Five participants walked in a controlled manner (60 cycles, 11 steps per cycle) across decks and then walked over various lanes of carpet to simulate the tracking of arsenic indoors on the bottoms of shoes under heavy foot traffic conditions. To determine if arsenic was transferred from the CCA-treated wood to the carpet via shoes, laboratory analysis was performed on three different types of samples: (1) wipe samples of dislodgeable arsenic from a 46 cm(2) area of carpet, (2) dust samples obtained from vacuuming a 7442 cm(2) area of carpet, and (3) extractions of 13 cm(2) carpet samples. Wipe samples were also taken directly from the deck lumber. Following digestion and extraction, the amount of arsenic in each sample was measured using Graphite Furnace Atomic Absorption Spectrometry. The mean arsenic concentration measured on the carpets was 2.52 microg/(100 cm(2)) and 2.05 microg/(100 cm(2)) with wipes for the dry and wet conditions, respectively, 4.69 microg/(100 cm(2)) and 0.68 microg/(100 cm(2)) with vacuumed dust for the dry and wet conditions, respectively, and 15.56 microg/(100 cm(2)) and 12.31 microg/(100 cm(2)) with carpet extractions for the dry and wet conditions, respectively. The mean arsenic concentration measured on the decks was 22.2 microg/(100 cm(2)) with wipes. Further research is needed to determine if indoor exposure to arsenic due to track-in from outdoor decks via foot traffic is significant compared to exposures from other sources.

Effects of fluoridation and disinfection agent combinations on lead leaching from leaded-brass parts.

This study concerns effects on water-borne lead from combinations of chlorine (CL) or chloramines (CA) with fluosilicic acid (FSA) or sodium fluoride (NaF). CL is known to corrode brass, releasing lead from plumbing devices. It is known that CA and CL in different ratios with ammonia (NH) mobilize copper from brass, which we have found also enhances elution of lead from leaded brass alloys. Phase I involved leaded-brass 1/4 in. elbows pre-conditioned in DI water and soaked in static solutions containing various combinations of CL, CA, FSA, NaF, and ammonium fluosilicate. In Phase II 20 leaded-brass alloy water meters were installed in pipe loops. After pre-conditioning the meters with 200 flushings with 1.0 ppm CL water, seven different solutions were pumped for a period of 6 weeks. Water samples were taken for lead analysis three times per week after a 16-h stagnation period. In the static testing with brass elbows, exposure to the waters with CA+50% excess NH3+FSA, with CA and ammonium fluosilicate, and with CA+FSA resulted in the highest estimated lead concentrations. In the flow-through brass meter tests, waters with CL+FSA, with CL+NaF, and with CL alone produced the highest average lead concentration for the first 3-week period. Over the last 3 weeks the highest lead concentrations were produced by CL+NaF, followed by CL alone and CA+NH3+FSA. Over the first test week (after CL flushing concentrations were increased from 1.0 to 2.0 ppm) lead concentrations nearly doubled (from about 100 to nearly 200 ppb), but when FSA was also included, lead concentrations spiked to over 900 ppb. Lead concentrations from the CL-based waters appeared to be decreasing over the study period, while for the CA+NH3+FSA combination, lead concentrations seemed to be increasing with time.

Reducing lead exposure from drinking water: recent history and current status.

This article discusses the issue of lead contamination of drinking water, noting the various regulatory-driven measures that have been adopted in the U.S. since 1986 to address this public health issue. The article summarizes the literature on the dynamics of tap water lead contamination and discusses this widespread source of lead exposure in the context of the latest research evidence.

Determination of the solids retainment effectiveness of disposable swim diapers.

In light of recent and increasing incidences of pathogenic E. coli outbreaks at public bathing facilities attributable to non-toilet-trained infants and toddlers, many such facilities are restricting water contact for this age group. A number of manufacturers are now offering disposable "swim diapers," which claim to effectively retain fecal material under typical pool play conditions. The study reported here examined the solids retention effectiveness of three major brands of swim diapers as well as of conventional disposable diapers, under simulated water play conditions. Swim diapers of all three brands exhibited an approximately equal fine-solids retention capability of about 98 to 99 percent over 30 minutes of water immersion activity. Conventional disposable diapers invariably fell down or came apart during the experiments, resulting in very limited solids retention. This study indicates that commercially available swim diapers represent a vast improvement in reducing the potential for fecal material release in public pool facilities, but that some release will still generally occur with these products.

Artificial Christmas trees: how real are the lead exposure risks?

Exposure to lead has long been recognized as a major public health issue in the United States and other industrialized nations. The health risks associated with low lead levels mean that consumer products (such as those made from polyvinyl chloride [PVC] plastic, which often incorporates lead as a stabilizer) with even moderate lead exposure risks could be dangerous. The purpose of the experiments reported in this article was to test for lead exposure from artificial Christmas trees made of PVC, which are now present in an estimated 50 million U.S. households. The first phase of experimentation tested artificial Christmas trees in the laboratory for lead content in branches, lead transfer from hand contact, and lead dust levels under the tree. The second phase was based on a field-testing survey of households with artificial Christmas trees. Results from these experiments show that, while the average artificial Christmas tree does not present a significant exposure risk, in the worst-case scenarios a substantial health risk to young children is quite possible.

An assessment of lead exposure potential from residential cutoff valves.

It is increasingly recognized that even very low lead exposure can result in measurable and permanent neurologic damage, especially to infants and young children. Although lead exposure from tap water continues to decline in the United States as a result of various regulatory and corrosion control measures, tap water continues to represent a significant (about 14 to 20 percent) source of total lead exposure. As of March 2002, nearly all valves used in residential plumbing systems continue to be made with 5 to 7 percent leaded brass. In this study, the authors measured the amount of lead discharged by these parts under laboratory conditions and found that the typical resident would be exposed to small amounts of lead, particularly from gate and ball valves. Typically, water passes through three to six such valves before reaching the tap. Thus, these leaded-brass valves represent a significant, widespread, and needless source of lead exposure to the U.S. public, especially given that numerous models of no-lead valves are now commercially available.